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OpenCloudOS-Kernel/fs/btrfs/extent-tree.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/sort.h>
#include <linux/rcupdate.h>
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/percpu_counter.h>
#include <linux/lockdep.h>
#include <linux/crc32c.h>
#include "tree-log.h"
#include "disk-io.h"
#include "print-tree.h"
#include "volumes.h"
#include "raid56.h"
#include "locking.h"
#include "free-space-cache.h"
#include "free-space-tree.h"
#include "math.h"
#include "sysfs.h"
#include "qgroup.h"
#include "ref-verify.h"
#include "space-info.h"
#include "block-rsv.h"
#include "delalloc-space.h"
#include "block-group.h"
#undef SCRAMBLE_DELAYED_REFS
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node, u64 parent,
u64 root_objectid, u64 owner_objectid,
u64 owner_offset, int refs_to_drop,
struct btrfs_delayed_extent_op *extra_op);
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
struct extent_buffer *leaf,
struct btrfs_extent_item *ei);
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
u64 flags, u64 owner, u64 offset,
struct btrfs_key *ins, int ref_mod);
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op);
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key);
static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
{
return (cache->flags & bits) == bits;
}
/*
* this adds the block group to the fs_info rb tree for the block group
* cache
*/
static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
struct btrfs_block_group_cache *block_group)
{
struct rb_node **p;
struct rb_node *parent = NULL;
struct btrfs_block_group_cache *cache;
spin_lock(&info->block_group_cache_lock);
p = &info->block_group_cache_tree.rb_node;
while (*p) {
parent = *p;
cache = rb_entry(parent, struct btrfs_block_group_cache,
cache_node);
if (block_group->key.objectid < cache->key.objectid) {
p = &(*p)->rb_left;
} else if (block_group->key.objectid > cache->key.objectid) {
p = &(*p)->rb_right;
} else {
spin_unlock(&info->block_group_cache_lock);
return -EEXIST;
}
}
rb_link_node(&block_group->cache_node, parent, p);
rb_insert_color(&block_group->cache_node,
&info->block_group_cache_tree);
if (info->first_logical_byte > block_group->key.objectid)
info->first_logical_byte = block_group->key.objectid;
spin_unlock(&info->block_group_cache_lock);
return 0;
}
int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 num_bytes)
{
u64 end = start + num_bytes - 1;
set_extent_bits(&fs_info->freed_extents[0],
start, end, EXTENT_UPTODATE);
set_extent_bits(&fs_info->freed_extents[1],
start, end, EXTENT_UPTODATE);
return 0;
}
void btrfs_free_excluded_extents(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
u64 start, end;
start = cache->key.objectid;
end = start + cache->key.offset - 1;
clear_extent_bits(&fs_info->freed_extents[0],
start, end, EXTENT_UPTODATE);
clear_extent_bits(&fs_info->freed_extents[1],
start, end, EXTENT_UPTODATE);
}
static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
u64 bytenr;
u64 *logical;
int stripe_len;
int i, nr, ret;
if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
cache->bytes_super += stripe_len;
ret = btrfs_add_excluded_extent(fs_info, cache->key.objectid,
stripe_len);
if (ret)
return ret;
}
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
ret = btrfs_rmap_block(fs_info, cache->key.objectid,
bytenr, &logical, &nr, &stripe_len);
if (ret)
return ret;
while (nr--) {
u64 start, len;
if (logical[nr] > cache->key.objectid +
cache->key.offset)
continue;
if (logical[nr] + stripe_len <= cache->key.objectid)
continue;
start = logical[nr];
if (start < cache->key.objectid) {
start = cache->key.objectid;
len = (logical[nr] + stripe_len) - start;
} else {
len = min_t(u64, stripe_len,
cache->key.objectid +
cache->key.offset - start);
}
cache->bytes_super += len;
ret = btrfs_add_excluded_extent(fs_info, start, len);
if (ret) {
kfree(logical);
return ret;
}
}
kfree(logical);
}
return 0;
}
struct btrfs_caching_control *btrfs_get_caching_control(
struct btrfs_block_group_cache *cache)
{
struct btrfs_caching_control *ctl;
spin_lock(&cache->lock);
if (!cache->caching_ctl) {
spin_unlock(&cache->lock);
return NULL;
}
ctl = cache->caching_ctl;
refcount_inc(&ctl->count);
spin_unlock(&cache->lock);
return ctl;
}
void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
{
if (refcount_dec_and_test(&ctl->count))
kfree(ctl);
}
#ifdef CONFIG_BTRFS_DEBUG
void btrfs_fragment_free_space(struct btrfs_block_group_cache *block_group)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
u64 start = block_group->key.objectid;
u64 len = block_group->key.offset;
u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
fs_info->nodesize : fs_info->sectorsize;
u64 step = chunk << 1;
while (len > chunk) {
btrfs_remove_free_space(block_group, start, chunk);
start += step;
if (len < step)
len = 0;
else
len -= step;
}
}
#endif
/*
* This is only called by btrfs_cache_block_group, since we could have freed
* extents we need to check the pinned_extents for any extents that can't be
* used yet since their free space will be released as soon as the transaction
* commits.
*/
u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
u64 start, u64 end)
{
struct btrfs_fs_info *info = block_group->fs_info;
u64 extent_start, extent_end, size, total_added = 0;
int ret;
while (start < end) {
ret = find_first_extent_bit(info->pinned_extents, start,
&extent_start, &extent_end,
EXTENT_DIRTY | EXTENT_UPTODATE,
NULL);
if (ret)
break;
if (extent_start <= start) {
start = extent_end + 1;
} else if (extent_start > start && extent_start < end) {
size = extent_start - start;
total_added += size;
ret = btrfs_add_free_space(block_group, start,
size);
BUG_ON(ret); /* -ENOMEM or logic error */
start = extent_end + 1;
} else {
break;
}
}
if (start < end) {
size = end - start;
total_added += size;
ret = btrfs_add_free_space(block_group, start, size);
BUG_ON(ret); /* -ENOMEM or logic error */
}
return total_added;
}
static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
{
struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_key key;
u64 total_found = 0;
u64 last = 0;
u32 nritems;
int ret;
bool wakeup = true;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
#ifdef CONFIG_BTRFS_DEBUG
/*
* If we're fragmenting we don't want to make anybody think we can
* allocate from this block group until we've had a chance to fragment
* the free space.
*/
if (btrfs_should_fragment_free_space(block_group))
wakeup = false;
#endif
/*
* We don't want to deadlock with somebody trying to allocate a new
* extent for the extent root while also trying to search the extent
* root to add free space. So we skip locking and search the commit
* root, since its read-only
*/
path->skip_locking = 1;
path->search_commit_root = 1;
path->reada = READA_FORWARD;
key.objectid = last;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;
next:
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
while (1) {
if (btrfs_fs_closing(fs_info) > 1) {
last = (u64)-1;
break;
}
if (path->slots[0] < nritems) {
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
} else {
ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
if (ret)
break;
if (need_resched() ||
rwsem_is_contended(&fs_info->commit_root_sem)) {
if (wakeup)
caching_ctl->progress = last;
btrfs_release_path(path);
up_read(&fs_info->commit_root_sem);
mutex_unlock(&caching_ctl->mutex);
cond_resched();
mutex_lock(&caching_ctl->mutex);
down_read(&fs_info->commit_root_sem);
goto next;
}
ret = btrfs_next_leaf(extent_root, path);
if (ret < 0)
goto out;
if (ret)
break;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
continue;
}
if (key.objectid < last) {
key.objectid = last;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;
if (wakeup)
caching_ctl->progress = last;
btrfs_release_path(path);
goto next;
}
if (key.objectid < block_group->key.objectid) {
path->slots[0]++;
continue;
}
if (key.objectid >= block_group->key.objectid +
block_group->key.offset)
break;
if (key.type == BTRFS_EXTENT_ITEM_KEY ||
key.type == BTRFS_METADATA_ITEM_KEY) {
total_found += add_new_free_space(block_group, last,
key.objectid);
if (key.type == BTRFS_METADATA_ITEM_KEY)
last = key.objectid +
fs_info->nodesize;
else
last = key.objectid + key.offset;
if (total_found > CACHING_CTL_WAKE_UP) {
total_found = 0;
if (wakeup)
wake_up(&caching_ctl->wait);
}
}
path->slots[0]++;
}
ret = 0;
total_found += add_new_free_space(block_group, last,
block_group->key.objectid +
block_group->key.offset);
caching_ctl->progress = (u64)-1;
out:
btrfs_free_path(path);
return ret;
}
static noinline void caching_thread(struct btrfs_work *work)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_fs_info *fs_info;
struct btrfs_caching_control *caching_ctl;
int ret;
caching_ctl = container_of(work, struct btrfs_caching_control, work);
block_group = caching_ctl->block_group;
fs_info = block_group->fs_info;
mutex_lock(&caching_ctl->mutex);
down_read(&fs_info->commit_root_sem);
if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
ret = load_free_space_tree(caching_ctl);
else
ret = load_extent_tree_free(caching_ctl);
spin_lock(&block_group->lock);
block_group->caching_ctl = NULL;
block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
spin_unlock(&block_group->lock);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(block_group)) {
u64 bytes_used;
spin_lock(&block_group->space_info->lock);
spin_lock(&block_group->lock);
bytes_used = block_group->key.offset -
btrfs_block_group_used(&block_group->item);
block_group->space_info->bytes_used += bytes_used >> 1;
spin_unlock(&block_group->lock);
spin_unlock(&block_group->space_info->lock);
btrfs_fragment_free_space(block_group);
}
#endif
caching_ctl->progress = (u64)-1;
up_read(&fs_info->commit_root_sem);
btrfs_free_excluded_extents(block_group);
mutex_unlock(&caching_ctl->mutex);
wake_up(&caching_ctl->wait);
btrfs_put_caching_control(caching_ctl);
btrfs_put_block_group(block_group);
}
int btrfs_cache_block_group(struct btrfs_block_group_cache *cache,
int load_cache_only)
{
DEFINE_WAIT(wait);
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_caching_control *caching_ctl;
int ret = 0;
caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
if (!caching_ctl)
return -ENOMEM;
INIT_LIST_HEAD(&caching_ctl->list);
mutex_init(&caching_ctl->mutex);
init_waitqueue_head(&caching_ctl->wait);
caching_ctl->block_group = cache;
caching_ctl->progress = cache->key.objectid;
refcount_set(&caching_ctl->count, 1);
btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
caching_thread, NULL, NULL);
spin_lock(&cache->lock);
/*
* This should be a rare occasion, but this could happen I think in the
* case where one thread starts to load the space cache info, and then
* some other thread starts a transaction commit which tries to do an
* allocation while the other thread is still loading the space cache
* info. The previous loop should have kept us from choosing this block
* group, but if we've moved to the state where we will wait on caching
* block groups we need to first check if we're doing a fast load here,
* so we can wait for it to finish, otherwise we could end up allocating
* from a block group who's cache gets evicted for one reason or
* another.
*/
while (cache->cached == BTRFS_CACHE_FAST) {
struct btrfs_caching_control *ctl;
ctl = cache->caching_ctl;
refcount_inc(&ctl->count);
prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&cache->lock);
schedule();
finish_wait(&ctl->wait, &wait);
btrfs_put_caching_control(ctl);
spin_lock(&cache->lock);
}
if (cache->cached != BTRFS_CACHE_NO) {
spin_unlock(&cache->lock);
kfree(caching_ctl);
return 0;
}
WARN_ON(cache->caching_ctl);
cache->caching_ctl = caching_ctl;
cache->cached = BTRFS_CACHE_FAST;
spin_unlock(&cache->lock);
if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
mutex_lock(&caching_ctl->mutex);
ret = load_free_space_cache(cache);
spin_lock(&cache->lock);
if (ret == 1) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_FINISHED;
cache->last_byte_to_unpin = (u64)-1;
caching_ctl->progress = (u64)-1;
} else {
if (load_cache_only) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_NO;
} else {
cache->cached = BTRFS_CACHE_STARTED;
cache->has_caching_ctl = 1;
}
}
spin_unlock(&cache->lock);
#ifdef CONFIG_BTRFS_DEBUG
if (ret == 1 &&
btrfs_should_fragment_free_space(cache)) {
u64 bytes_used;
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
bytes_used = cache->key.offset -
btrfs_block_group_used(&cache->item);
cache->space_info->bytes_used += bytes_used >> 1;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
btrfs_fragment_free_space(cache);
}
#endif
mutex_unlock(&caching_ctl->mutex);
wake_up(&caching_ctl->wait);
if (ret == 1) {
btrfs_put_caching_control(caching_ctl);
btrfs_free_excluded_extents(cache);
return 0;
}
} else {
/*
* We're either using the free space tree or no caching at all.
* Set cached to the appropriate value and wakeup any waiters.
*/
spin_lock(&cache->lock);
if (load_cache_only) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_NO;
} else {
cache->cached = BTRFS_CACHE_STARTED;
cache->has_caching_ctl = 1;
}
spin_unlock(&cache->lock);
wake_up(&caching_ctl->wait);
}
if (load_cache_only) {
btrfs_put_caching_control(caching_ctl);
return 0;
}
down_write(&fs_info->commit_root_sem);
refcount_inc(&caching_ctl->count);
list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
up_write(&fs_info->commit_root_sem);
btrfs_get_block_group(cache);
btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
return ret;
}
static u64 generic_ref_to_space_flags(struct btrfs_ref *ref)
{
if (ref->type == BTRFS_REF_METADATA) {
if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
return BTRFS_BLOCK_GROUP_SYSTEM;
else
return BTRFS_BLOCK_GROUP_METADATA;
}
return BTRFS_BLOCK_GROUP_DATA;
}
static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
struct btrfs_ref *ref)
{
struct btrfs_space_info *space_info;
u64 flags = generic_ref_to_space_flags(ref);
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
percpu_counter_add_batch(&space_info->total_bytes_pinned, ref->len,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
}
static void sub_pinned_bytes(struct btrfs_fs_info *fs_info,
struct btrfs_ref *ref)
{
struct btrfs_space_info *space_info;
u64 flags = generic_ref_to_space_flags(ref);
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
percpu_counter_add_batch(&space_info->total_bytes_pinned, -ref->len,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
}
/* simple helper to search for an existing data extent at a given offset */
int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
{
int ret;
struct btrfs_key key;
struct btrfs_path *path;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = start;
key.offset = len;
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
btrfs_free_path(path);
return ret;
}
/*
* helper function to lookup reference count and flags of a tree block.
*
* the head node for delayed ref is used to store the sum of all the
* reference count modifications queued up in the rbtree. the head
* node may also store the extent flags to set. This way you can check
* to see what the reference count and extent flags would be if all of
* the delayed refs are not processed.
*/
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 offset, int metadata, u64 *refs, u64 *flags)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_path *path;
struct btrfs_extent_item *ei;
struct extent_buffer *leaf;
struct btrfs_key key;
u32 item_size;
u64 num_refs;
u64 extent_flags;
int ret;
/*
* If we don't have skinny metadata, don't bother doing anything
* different
*/
if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
offset = fs_info->nodesize;
metadata = 0;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (!trans) {
path->skip_locking = 1;
path->search_commit_root = 1;
}
search_again:
key.objectid = bytenr;
key.offset = offset;
if (metadata)
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
if (ret < 0)
goto out_free;
if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
if (path->slots[0]) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == fs_info->nodesize)
ret = 0;
}
}
if (ret == 0) {
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (item_size >= sizeof(*ei)) {
ei = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
num_refs = btrfs_extent_refs(leaf, ei);
extent_flags = btrfs_extent_flags(leaf, ei);
} else {
ret = -EINVAL;
btrfs_print_v0_err(fs_info);
if (trans)
btrfs_abort_transaction(trans, ret);
else
btrfs_handle_fs_error(fs_info, ret, NULL);
goto out_free;
}
BUG_ON(num_refs == 0);
} else {
num_refs = 0;
extent_flags = 0;
ret = 0;
}
if (!trans)
goto out;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (head) {
if (!mutex_trylock(&head->mutex)) {
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's released and try
* again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
goto search_again;
}
spin_lock(&head->lock);
if (head->extent_op && head->extent_op->update_flags)
extent_flags |= head->extent_op->flags_to_set;
else
BUG_ON(num_refs == 0);
num_refs += head->ref_mod;
spin_unlock(&head->lock);
mutex_unlock(&head->mutex);
}
spin_unlock(&delayed_refs->lock);
out:
WARN_ON(num_refs == 0);
if (refs)
*refs = num_refs;
if (flags)
*flags = extent_flags;
out_free:
btrfs_free_path(path);
return ret;
}
/*
* Back reference rules. Back refs have three main goals:
*
* 1) differentiate between all holders of references to an extent so that
* when a reference is dropped we can make sure it was a valid reference
* before freeing the extent.
*
* 2) Provide enough information to quickly find the holders of an extent
* if we notice a given block is corrupted or bad.
*
* 3) Make it easy to migrate blocks for FS shrinking or storage pool
* maintenance. This is actually the same as #2, but with a slightly
* different use case.
*
* There are two kinds of back refs. The implicit back refs is optimized
* for pointers in non-shared tree blocks. For a given pointer in a block,
* back refs of this kind provide information about the block's owner tree
* and the pointer's key. These information allow us to find the block by
* b-tree searching. The full back refs is for pointers in tree blocks not
* referenced by their owner trees. The location of tree block is recorded
* in the back refs. Actually the full back refs is generic, and can be
* used in all cases the implicit back refs is used. The major shortcoming
* of the full back refs is its overhead. Every time a tree block gets
* COWed, we have to update back refs entry for all pointers in it.
*
* For a newly allocated tree block, we use implicit back refs for
* pointers in it. This means most tree related operations only involve
* implicit back refs. For a tree block created in old transaction, the
* only way to drop a reference to it is COW it. So we can detect the
* event that tree block loses its owner tree's reference and do the
* back refs conversion.
*
* When a tree block is COWed through a tree, there are four cases:
*
* The reference count of the block is one and the tree is the block's
* owner tree. Nothing to do in this case.
*
* The reference count of the block is one and the tree is not the
* block's owner tree. In this case, full back refs is used for pointers
* in the block. Remove these full back refs, add implicit back refs for
* every pointers in the new block.
*
* The reference count of the block is greater than one and the tree is
* the block's owner tree. In this case, implicit back refs is used for
* pointers in the block. Add full back refs for every pointers in the
* block, increase lower level extents' reference counts. The original
* implicit back refs are entailed to the new block.
*
* The reference count of the block is greater than one and the tree is
* not the block's owner tree. Add implicit back refs for every pointer in
* the new block, increase lower level extents' reference count.
*
* Back Reference Key composing:
*
* The key objectid corresponds to the first byte in the extent,
* The key type is used to differentiate between types of back refs.
* There are different meanings of the key offset for different types
* of back refs.
*
* File extents can be referenced by:
*
* - multiple snapshots, subvolumes, or different generations in one subvol
* - different files inside a single subvolume
* - different offsets inside a file (bookend extents in file.c)
*
* The extent ref structure for the implicit back refs has fields for:
*
* - Objectid of the subvolume root
* - objectid of the file holding the reference
* - original offset in the file
* - how many bookend extents
*
* The key offset for the implicit back refs is hash of the first
* three fields.
*
* The extent ref structure for the full back refs has field for:
*
* - number of pointers in the tree leaf
*
* The key offset for the implicit back refs is the first byte of
* the tree leaf
*
* When a file extent is allocated, The implicit back refs is used.
* the fields are filled in:
*
* (root_key.objectid, inode objectid, offset in file, 1)
*
* When a file extent is removed file truncation, we find the
* corresponding implicit back refs and check the following fields:
*
* (btrfs_header_owner(leaf), inode objectid, offset in file)
*
* Btree extents can be referenced by:
*
* - Different subvolumes
*
* Both the implicit back refs and the full back refs for tree blocks
* only consist of key. The key offset for the implicit back refs is
* objectid of block's owner tree. The key offset for the full back refs
* is the first byte of parent block.
*
* When implicit back refs is used, information about the lowest key and
* level of the tree block are required. These information are stored in
* tree block info structure.
*/
/*
* is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
* is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
* is_data == BTRFS_REF_TYPE_ANY, either type is OK.
*/
int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
struct btrfs_extent_inline_ref *iref,
enum btrfs_inline_ref_type is_data)
{
int type = btrfs_extent_inline_ref_type(eb, iref);
u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
type == BTRFS_SHARED_BLOCK_REF_KEY ||
type == BTRFS_SHARED_DATA_REF_KEY ||
type == BTRFS_EXTENT_DATA_REF_KEY) {
if (is_data == BTRFS_REF_TYPE_BLOCK) {
if (type == BTRFS_TREE_BLOCK_REF_KEY)
return type;
if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
ASSERT(eb->fs_info);
/*
* Every shared one has parent tree
* block, which must be aligned to
* nodesize.
*/
if (offset &&
IS_ALIGNED(offset, eb->fs_info->nodesize))
return type;
}
} else if (is_data == BTRFS_REF_TYPE_DATA) {
if (type == BTRFS_EXTENT_DATA_REF_KEY)
return type;
if (type == BTRFS_SHARED_DATA_REF_KEY) {
ASSERT(eb->fs_info);
/*
* Every shared one has parent tree
* block, which must be aligned to
* nodesize.
*/
if (offset &&
IS_ALIGNED(offset, eb->fs_info->nodesize))
return type;
}
} else {
ASSERT(is_data == BTRFS_REF_TYPE_ANY);
return type;
}
}
btrfs_print_leaf((struct extent_buffer *)eb);
btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
eb->start, type);
WARN_ON(1);
return BTRFS_REF_TYPE_INVALID;
}
static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
{
u32 high_crc = ~(u32)0;
u32 low_crc = ~(u32)0;
__le64 lenum;
lenum = cpu_to_le64(root_objectid);
high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
lenum = cpu_to_le64(owner);
low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
lenum = cpu_to_le64(offset);
low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
return ((u64)high_crc << 31) ^ (u64)low_crc;
}
static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
struct btrfs_extent_data_ref *ref)
{
return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
btrfs_extent_data_ref_objectid(leaf, ref),
btrfs_extent_data_ref_offset(leaf, ref));
}
static int match_extent_data_ref(struct extent_buffer *leaf,
struct btrfs_extent_data_ref *ref,
u64 root_objectid, u64 owner, u64 offset)
{
if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
btrfs_extent_data_ref_offset(leaf, ref) != offset)
return 0;
return 1;
}
static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid,
u64 owner, u64 offset)
{
struct btrfs_root *root = trans->fs_info->extent_root;
struct btrfs_key key;
struct btrfs_extent_data_ref *ref;
struct extent_buffer *leaf;
u32 nritems;
int ret;
int recow;
int err = -ENOENT;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_DATA_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_EXTENT_DATA_REF_KEY;
key.offset = hash_extent_data_ref(root_objectid,
owner, offset);
}
again:
recow = 0;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0) {
err = ret;
goto fail;
}
if (parent) {
if (!ret)
return 0;
goto fail;
}
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
while (1) {
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
err = ret;
if (ret)
goto fail;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
recow = 1;
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr ||
key.type != BTRFS_EXTENT_DATA_REF_KEY)
goto fail;
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (match_extent_data_ref(leaf, ref, root_objectid,
owner, offset)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
err = 0;
break;
}
path->slots[0]++;
}
fail:
return err;
}
static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid, u64 owner,
u64 offset, int refs_to_add)
{
struct btrfs_root *root = trans->fs_info->extent_root;
struct btrfs_key key;
struct extent_buffer *leaf;
u32 size;
u32 num_refs;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_DATA_REF_KEY;
key.offset = parent;
size = sizeof(struct btrfs_shared_data_ref);
} else {
key.type = BTRFS_EXTENT_DATA_REF_KEY;
key.offset = hash_extent_data_ref(root_objectid,
owner, offset);
size = sizeof(struct btrfs_extent_data_ref);
}
ret = btrfs_insert_empty_item(trans, root, path, &key, size);
if (ret && ret != -EEXIST)
goto fail;
leaf = path->nodes[0];
if (parent) {
struct btrfs_shared_data_ref *ref;
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
if (ret == 0) {
btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
} else {
num_refs = btrfs_shared_data_ref_count(leaf, ref);
num_refs += refs_to_add;
btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
}
} else {
struct btrfs_extent_data_ref *ref;
while (ret == -EEXIST) {
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (match_extent_data_ref(leaf, ref, root_objectid,
owner, offset))
break;
btrfs_release_path(path);
key.offset++;
ret = btrfs_insert_empty_item(trans, root, path, &key,
size);
if (ret && ret != -EEXIST)
goto fail;
leaf = path->nodes[0];
}
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (ret == 0) {
btrfs_set_extent_data_ref_root(leaf, ref,
root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
} else {
num_refs = btrfs_extent_data_ref_count(leaf, ref);
num_refs += refs_to_add;
btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
}
}
btrfs_mark_buffer_dirty(leaf);
ret = 0;
fail:
btrfs_release_path(path);
return ret;
}
static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
int refs_to_drop, int *last_ref)
{
struct btrfs_key key;
struct btrfs_extent_data_ref *ref1 = NULL;
struct btrfs_shared_data_ref *ref2 = NULL;
struct extent_buffer *leaf;
u32 num_refs = 0;
int ret = 0;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
btrfs_print_v0_err(trans->fs_info);
btrfs_abort_transaction(trans, -EINVAL);
return -EINVAL;
} else {
BUG();
}
BUG_ON(num_refs < refs_to_drop);
num_refs -= refs_to_drop;
if (num_refs == 0) {
ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
*last_ref = 1;
} else {
if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
btrfs_mark_buffer_dirty(leaf);
}
return ret;
}
static noinline u32 extent_data_ref_count(struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref)
{
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_extent_data_ref *ref1;
struct btrfs_shared_data_ref *ref2;
u32 num_refs = 0;
int type;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
if (iref) {
/*
* If type is invalid, we should have bailed out earlier than
* this call.
*/
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
ASSERT(type != BTRFS_REF_TYPE_INVALID);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else {
ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
}
} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
} else {
WARN_ON(1);
}
return num_refs;
}
static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid)
{
struct btrfs_root *root = trans->fs_info->extent_root;
struct btrfs_key key;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_TREE_BLOCK_REF_KEY;
key.offset = root_objectid;
}
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
return ret;
}
static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid)
{
struct btrfs_key key;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_TREE_BLOCK_REF_KEY;
key.offset = root_objectid;
}
ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
path, &key, 0);
btrfs_release_path(path);
return ret;
}
static inline int extent_ref_type(u64 parent, u64 owner)
{
int type;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
if (parent > 0)
type = BTRFS_SHARED_BLOCK_REF_KEY;
else
type = BTRFS_TREE_BLOCK_REF_KEY;
} else {
if (parent > 0)
type = BTRFS_SHARED_DATA_REF_KEY;
else
type = BTRFS_EXTENT_DATA_REF_KEY;
}
return type;
}
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key)
{
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path->nodes[level])
break;
if (path->slots[level] + 1 >=
btrfs_header_nritems(path->nodes[level]))
continue;
if (level == 0)
btrfs_item_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
else
btrfs_node_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
return 0;
}
return 1;
}
/*
* look for inline back ref. if back ref is found, *ref_ret is set
* to the address of inline back ref, and 0 is returned.
*
* if back ref isn't found, *ref_ret is set to the address where it
* should be inserted, and -ENOENT is returned.
*
* if insert is true and there are too many inline back refs, the path
* points to the extent item, and -EAGAIN is returned.
*
* NOTE: inline back refs are ordered in the same way that back ref
* items in the tree are ordered.
*/
static noinline_for_stack
int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref **ref_ret,
u64 bytenr, u64 num_bytes,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int insert)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
u64 flags;
u64 item_size;
unsigned long ptr;
unsigned long end;
int extra_size;
int type;
int want;
int ret;
int err = 0;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
int needed;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
want = extent_ref_type(parent, owner);
if (insert) {
extra_size = btrfs_extent_inline_ref_size(want);
path->keep_locks = 1;
} else
extra_size = -1;
/*
* Owner is our level, so we can just add one to get the level for the
* block we are interested in.
*/
if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = owner;
}
again:
ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
if (ret < 0) {
err = ret;
goto out;
}
/*
* We may be a newly converted file system which still has the old fat
* extent entries for metadata, so try and see if we have one of those.
*/
if (ret > 0 && skinny_metadata) {
skinny_metadata = false;
if (path->slots[0]) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes)
ret = 0;
}
if (ret) {
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
btrfs_release_path(path);
goto again;
}
}
if (ret && !insert) {
err = -ENOENT;
goto out;
} else if (WARN_ON(ret)) {
err = -EIO;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
err = -EINVAL;
btrfs_print_v0_err(fs_info);
btrfs_abort_transaction(trans, err);
goto out;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
flags = btrfs_extent_flags(leaf, ei);
ptr = (unsigned long)(ei + 1);
end = (unsigned long)ei + item_size;
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
ptr += sizeof(struct btrfs_tree_block_info);
BUG_ON(ptr > end);
}
if (owner >= BTRFS_FIRST_FREE_OBJECTID)
needed = BTRFS_REF_TYPE_DATA;
else
needed = BTRFS_REF_TYPE_BLOCK;
err = -ENOENT;
while (1) {
if (ptr >= end) {
WARN_ON(ptr > end);
break;
}
iref = (struct btrfs_extent_inline_ref *)ptr;
type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
if (type == BTRFS_REF_TYPE_INVALID) {
err = -EUCLEAN;
goto out;
}
if (want < type)
break;
if (want > type) {
ptr += btrfs_extent_inline_ref_size(type);
continue;
}
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
struct btrfs_extent_data_ref *dref;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (match_extent_data_ref(leaf, dref, root_objectid,
owner, offset)) {
err = 0;
break;
}
if (hash_extent_data_ref_item(leaf, dref) <
hash_extent_data_ref(root_objectid, owner, offset))
break;
} else {
u64 ref_offset;
ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
if (parent > 0) {
if (parent == ref_offset) {
err = 0;
break;
}
if (ref_offset < parent)
break;
} else {
if (root_objectid == ref_offset) {
err = 0;
break;
}
if (ref_offset < root_objectid)
break;
}
}
ptr += btrfs_extent_inline_ref_size(type);
}
if (err == -ENOENT && insert) {
if (item_size + extra_size >=
BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
err = -EAGAIN;
goto out;
}
/*
* To add new inline back ref, we have to make sure
* there is no corresponding back ref item.
* For simplicity, we just do not add new inline back
* ref if there is any kind of item for this block
*/
if (find_next_key(path, 0, &key) == 0 &&
key.objectid == bytenr &&
key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
err = -EAGAIN;
goto out;
}
}
*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
out:
if (insert) {
path->keep_locks = 0;
btrfs_unlock_up_safe(path, 1);
}
return err;
}
/*
* helper to add new inline back ref
*/
static noinline_for_stack
void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
unsigned long ptr;
unsigned long end;
unsigned long item_offset;
u64 refs;
int size;
int type;
leaf = path->nodes[0];
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
item_offset = (unsigned long)iref - (unsigned long)ei;
type = extent_ref_type(parent, owner);
size = btrfs_extent_inline_ref_size(type);
btrfs_extend_item(path, size);
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
refs += refs_to_add;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
ptr = (unsigned long)ei + item_offset;
end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
if (ptr < end - size)
memmove_extent_buffer(leaf, ptr + size, ptr,
end - size - ptr);
iref = (struct btrfs_extent_inline_ref *)ptr;
btrfs_set_extent_inline_ref_type(leaf, iref, type);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
struct btrfs_extent_data_ref *dref;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
btrfs_set_extent_data_ref_offset(leaf, dref, offset);
btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
struct btrfs_shared_data_ref *sref;
sref = (struct btrfs_shared_data_ref *)(iref + 1);
btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
} else {
btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
}
btrfs_mark_buffer_dirty(leaf);
}
static int lookup_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref **ref_ret,
u64 bytenr, u64 num_bytes, u64 parent,
u64 root_objectid, u64 owner, u64 offset)
{
int ret;
ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
num_bytes, parent, root_objectid,
owner, offset, 0);
if (ret != -ENOENT)
return ret;
btrfs_release_path(path);
*ref_ret = NULL;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
ret = lookup_tree_block_ref(trans, path, bytenr, parent,
root_objectid);
} else {
ret = lookup_extent_data_ref(trans, path, bytenr, parent,
root_objectid, owner, offset);
}
return ret;
}
/*
* helper to update/remove inline back ref
*/
static noinline_for_stack
void update_inline_extent_backref(struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_mod,
struct btrfs_delayed_extent_op *extent_op,
int *last_ref)
{
struct extent_buffer *leaf = path->nodes[0];
struct btrfs_extent_item *ei;
struct btrfs_extent_data_ref *dref = NULL;
struct btrfs_shared_data_ref *sref = NULL;
unsigned long ptr;
unsigned long end;
u32 item_size;
int size;
int type;
u64 refs;
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
refs += refs_to_mod;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
/*
* If type is invalid, we should have bailed out after
* lookup_inline_extent_backref().
*/
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
ASSERT(type != BTRFS_REF_TYPE_INVALID);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
refs = btrfs_extent_data_ref_count(leaf, dref);
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
sref = (struct btrfs_shared_data_ref *)(iref + 1);
refs = btrfs_shared_data_ref_count(leaf, sref);
} else {
refs = 1;
BUG_ON(refs_to_mod != -1);
}
BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
refs += refs_to_mod;
if (refs > 0) {
if (type == BTRFS_EXTENT_DATA_REF_KEY)
btrfs_set_extent_data_ref_count(leaf, dref, refs);
else
btrfs_set_shared_data_ref_count(leaf, sref, refs);
} else {
*last_ref = 1;
size = btrfs_extent_inline_ref_size(type);
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ptr = (unsigned long)iref;
end = (unsigned long)ei + item_size;
if (ptr + size < end)
memmove_extent_buffer(leaf, ptr, ptr + size,
end - ptr - size);
item_size -= size;
btrfs_truncate_item(path, item_size, 1);
}
btrfs_mark_buffer_dirty(leaf);
}
static noinline_for_stack
int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 num_bytes, u64 parent,
u64 root_objectid, u64 owner,
u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_extent_inline_ref *iref;
int ret;
ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
num_bytes, parent, root_objectid,
owner, offset, 1);
if (ret == 0) {
BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
update_inline_extent_backref(path, iref, refs_to_add,
extent_op, NULL);
} else if (ret == -ENOENT) {
setup_inline_extent_backref(trans->fs_info, path, iref, parent,
root_objectid, owner, offset,
refs_to_add, extent_op);
ret = 0;
}
return ret;
}
static int insert_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add)
{
int ret;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
BUG_ON(refs_to_add != 1);
ret = insert_tree_block_ref(trans, path, bytenr, parent,
root_objectid);
} else {
ret = insert_extent_data_ref(trans, path, bytenr, parent,
root_objectid, owner, offset,
refs_to_add);
}
return ret;
}
static int remove_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_drop, int is_data, int *last_ref)
{
int ret = 0;
BUG_ON(!is_data && refs_to_drop != 1);
if (iref) {
update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
last_ref);
} else if (is_data) {
ret = remove_extent_data_ref(trans, path, refs_to_drop,
last_ref);
} else {
*last_ref = 1;
ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
}
return ret;
}
static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
u64 *discarded_bytes)
{
int j, ret = 0;
u64 bytes_left, end;
u64 aligned_start = ALIGN(start, 1 << 9);
if (WARN_ON(start != aligned_start)) {
len -= aligned_start - start;
len = round_down(len, 1 << 9);
start = aligned_start;
}
*discarded_bytes = 0;
if (!len)
return 0;
end = start + len;
bytes_left = len;
/* Skip any superblocks on this device. */
for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
u64 sb_start = btrfs_sb_offset(j);
u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
u64 size = sb_start - start;
if (!in_range(sb_start, start, bytes_left) &&
!in_range(sb_end, start, bytes_left) &&
!in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
continue;
/*
* Superblock spans beginning of range. Adjust start and
* try again.
*/
if (sb_start <= start) {
start += sb_end - start;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
continue;
}
if (size) {
ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
GFP_NOFS, 0);
if (!ret)
*discarded_bytes += size;
else if (ret != -EOPNOTSUPP)
return ret;
}
start = sb_end;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
}
if (bytes_left) {
ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
GFP_NOFS, 0);
if (!ret)
*discarded_bytes += bytes_left;
}
return ret;
}
int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
u64 num_bytes, u64 *actual_bytes)
{
int ret;
u64 discarded_bytes = 0;
struct btrfs_bio *bbio = NULL;
/*
* Avoid races with device replace and make sure our bbio has devices
* associated to its stripes that don't go away while we are discarding.
*/
btrfs_bio_counter_inc_blocked(fs_info);
/* Tell the block device(s) that the sectors can be discarded */
ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
&bbio, 0);
/* Error condition is -ENOMEM */
if (!ret) {
struct btrfs_bio_stripe *stripe = bbio->stripes;
int i;
for (i = 0; i < bbio->num_stripes; i++, stripe++) {
u64 bytes;
struct request_queue *req_q;
if (!stripe->dev->bdev) {
ASSERT(btrfs_test_opt(fs_info, DEGRADED));
continue;
}
req_q = bdev_get_queue(stripe->dev->bdev);
if (!blk_queue_discard(req_q))
continue;
ret = btrfs_issue_discard(stripe->dev->bdev,
stripe->physical,
stripe->length,
&bytes);
if (!ret)
discarded_bytes += bytes;
else if (ret != -EOPNOTSUPP)
break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
/*
* Just in case we get back EOPNOTSUPP for some reason,
* just ignore the return value so we don't screw up
* people calling discard_extent.
*/
ret = 0;
}
btrfs_put_bbio(bbio);
}
btrfs_bio_counter_dec(fs_info);
if (actual_bytes)
*actual_bytes = discarded_bytes;
if (ret == -EOPNOTSUPP)
ret = 0;
return ret;
}
/* Can return -ENOMEM */
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_ref *generic_ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int old_ref_mod, new_ref_mod;
int ret;
ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
generic_ref->action);
BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
generic_ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID);
if (generic_ref->type == BTRFS_REF_METADATA)
ret = btrfs_add_delayed_tree_ref(trans, generic_ref,
NULL, &old_ref_mod, &new_ref_mod);
else
ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0,
&old_ref_mod, &new_ref_mod);
btrfs_ref_tree_mod(fs_info, generic_ref);
if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
sub_pinned_bytes(fs_info, generic_ref);
return ret;
}
/*
* __btrfs_inc_extent_ref - insert backreference for a given extent
*
* @trans: Handle of transaction
*
* @node: The delayed ref node used to get the bytenr/length for
* extent whose references are incremented.
*
* @parent: If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
* BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
* bytenr of the parent block. Since new extents are always
* created with indirect references, this will only be the case
* when relocating a shared extent. In that case, root_objectid
* will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
* be 0
*
* @root_objectid: The id of the root where this modification has originated,
* this can be either one of the well-known metadata trees or
* the subvolume id which references this extent.
*
* @owner: For data extents it is the inode number of the owning file.
* For metadata extents this parameter holds the level in the
* tree of the extent.
*
* @offset: For metadata extents the offset is ignored and is currently
* always passed as 0. For data extents it is the fileoffset
* this extent belongs to.
*
* @refs_to_add Number of references to add
*
* @extent_op Pointer to a structure, holding information necessary when
* updating a tree block's flags
*
*/
static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_extent_item *item;
struct btrfs_key key;
u64 bytenr = node->bytenr;
u64 num_bytes = node->num_bytes;
u64 refs;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
path->leave_spinning = 1;
/* this will setup the path even if it fails to insert the back ref */
ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
parent, root_objectid, owner,
offset, refs_to_add, extent_op);
if ((ret < 0 && ret != -EAGAIN) || !ret)
goto out;
/*
* Ok we had -EAGAIN which means we didn't have space to insert and
* inline extent ref, so just update the reference count and add a
* normal backref.
*/
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, item);
btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, item);
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
path->reada = READA_FORWARD;
path->leave_spinning = 1;
/* now insert the actual backref */
ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
owner, offset, refs_to_add);
if (ret)
btrfs_abort_transaction(trans, ret);
out:
btrfs_free_path(path);
return ret;
}
static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
int insert_reserved)
{
int ret = 0;
struct btrfs_delayed_data_ref *ref;
struct btrfs_key ins;
u64 parent = 0;
u64 ref_root = 0;
u64 flags = 0;
ins.objectid = node->bytenr;
ins.offset = node->num_bytes;
ins.type = BTRFS_EXTENT_ITEM_KEY;
ref = btrfs_delayed_node_to_data_ref(node);
trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
if (node->type == BTRFS_SHARED_DATA_REF_KEY)
parent = ref->parent;
ref_root = ref->root;
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
if (extent_op)
flags |= extent_op->flags_to_set;
ret = alloc_reserved_file_extent(trans, parent, ref_root,
flags, ref->objectid,
ref->offset, &ins,
node->ref_mod);
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
ref->objectid, ref->offset,
node->ref_mod, extent_op);
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
ret = __btrfs_free_extent(trans, node, parent,
ref_root, ref->objectid,
ref->offset, node->ref_mod,
extent_op);
} else {
BUG();
}
return ret;
}
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
struct extent_buffer *leaf,
struct btrfs_extent_item *ei)
{
u64 flags = btrfs_extent_flags(leaf, ei);
if (extent_op->update_flags) {
flags |= extent_op->flags_to_set;
btrfs_set_extent_flags(leaf, ei, flags);
}
if (extent_op->update_key) {
struct btrfs_tree_block_info *bi;
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
bi = (struct btrfs_tree_block_info *)(ei + 1);
btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
}
}
static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_extent_item *ei;
struct extent_buffer *leaf;
u32 item_size;
int ret;
int err = 0;
int metadata = !extent_op->is_data;
if (trans->aborted)
return 0;
if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
metadata = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = head->bytenr;
if (metadata) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = extent_op->level;
} else {
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = head->num_bytes;
}
again:
path->reada = READA_FORWARD;
path->leave_spinning = 1;
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
if (ret < 0) {
err = ret;
goto out;
}
if (ret > 0) {
if (metadata) {
if (path->slots[0] > 0) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == head->bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == head->num_bytes)
ret = 0;
}
if (ret > 0) {
btrfs_release_path(path);
metadata = 0;
key.objectid = head->bytenr;
key.offset = head->num_bytes;
key.type = BTRFS_EXTENT_ITEM_KEY;
goto again;
}
} else {
err = -EIO;
goto out;
}
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
err = -EINVAL;
btrfs_print_v0_err(fs_info);
btrfs_abort_transaction(trans, err);
goto out;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
__run_delayed_extent_op(extent_op, leaf, ei);
btrfs_mark_buffer_dirty(leaf);
out:
btrfs_free_path(path);
return err;
}
static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
int insert_reserved)
{
int ret = 0;
struct btrfs_delayed_tree_ref *ref;
u64 parent = 0;
u64 ref_root = 0;
ref = btrfs_delayed_node_to_tree_ref(node);
trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
parent = ref->parent;
ref_root = ref->root;
if (node->ref_mod != 1) {
btrfs_err(trans->fs_info,
"btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
node->bytenr, node->ref_mod, node->action, ref_root,
parent);
return -EIO;
}
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
BUG_ON(!extent_op || !extent_op->update_flags);
ret = alloc_reserved_tree_block(trans, node, extent_op);
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
ref->level, 0, 1, extent_op);
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
ret = __btrfs_free_extent(trans, node, parent, ref_root,
ref->level, 0, 1, extent_op);
} else {
BUG();
}
return ret;
}
/* helper function to actually process a single delayed ref entry */
static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
int insert_reserved)
{
int ret = 0;
if (trans->aborted) {
if (insert_reserved)
btrfs_pin_extent(trans->fs_info, node->bytenr,
node->num_bytes, 1);
return 0;
}
if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
node->type == BTRFS_SHARED_BLOCK_REF_KEY)
ret = run_delayed_tree_ref(trans, node, extent_op,
insert_reserved);
else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
node->type == BTRFS_SHARED_DATA_REF_KEY)
ret = run_delayed_data_ref(trans, node, extent_op,
insert_reserved);
else
BUG();
if (ret && insert_reserved)
btrfs_pin_extent(trans->fs_info, node->bytenr,
node->num_bytes, 1);
return ret;
}
static inline struct btrfs_delayed_ref_node *
select_delayed_ref(struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_ref_node *ref;
if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
return NULL;
/*
* Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
* This is to prevent a ref count from going down to zero, which deletes
* the extent item from the extent tree, when there still are references
* to add, which would fail because they would not find the extent item.
*/
if (!list_empty(&head->ref_add_list))
return list_first_entry(&head->ref_add_list,
struct btrfs_delayed_ref_node, add_list);
ref = rb_entry(rb_first_cached(&head->ref_tree),
struct btrfs_delayed_ref_node, ref_node);
ASSERT(list_empty(&ref->add_list));
return ref;
}
static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
spin_lock(&delayed_refs->lock);
head->processing = 0;
delayed_refs->num_heads_ready++;
spin_unlock(&delayed_refs->lock);
btrfs_delayed_ref_unlock(head);
}
static struct btrfs_delayed_extent_op *cleanup_extent_op(
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
if (!extent_op)
return NULL;
if (head->must_insert_reserved) {
head->extent_op = NULL;
btrfs_free_delayed_extent_op(extent_op);
return NULL;
}
return extent_op;
}
static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_extent_op *extent_op;
int ret;
extent_op = cleanup_extent_op(head);
if (!extent_op)
return 0;
head->extent_op = NULL;
spin_unlock(&head->lock);
ret = run_delayed_extent_op(trans, head, extent_op);
btrfs_free_delayed_extent_op(extent_op);
return ret ? ret : 1;
}
void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
int nr_items = 1; /* Dropping this ref head update. */
if (head->total_ref_mod < 0) {
struct btrfs_space_info *space_info;
u64 flags;
if (head->is_data)
flags = BTRFS_BLOCK_GROUP_DATA;
else if (head->is_system)
flags = BTRFS_BLOCK_GROUP_SYSTEM;
else
flags = BTRFS_BLOCK_GROUP_METADATA;
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-head->num_bytes,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
/*
* We had csum deletions accounted for in our delayed refs rsv,
* we need to drop the csum leaves for this update from our
* delayed_refs_rsv.
*/
if (head->is_data) {
spin_lock(&delayed_refs->lock);
delayed_refs->pending_csums -= head->num_bytes;
spin_unlock(&delayed_refs->lock);
nr_items += btrfs_csum_bytes_to_leaves(fs_info,
head->num_bytes);
}
}
btrfs_delayed_refs_rsv_release(fs_info, nr_items);
}
static int cleanup_ref_head(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
int ret;
delayed_refs = &trans->transaction->delayed_refs;
ret = run_and_cleanup_extent_op(trans, head);
if (ret < 0) {
unselect_delayed_ref_head(delayed_refs, head);
btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
return ret;
} else if (ret) {
return ret;
}
/*
* Need to drop our head ref lock and re-acquire the delayed ref lock
* and then re-check to make sure nobody got added.
*/
spin_unlock(&head->lock);
spin_lock(&delayed_refs->lock);
spin_lock(&head->lock);
if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
return 1;
}
btrfs_delete_ref_head(delayed_refs, head);
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
if (head->must_insert_reserved) {
btrfs_pin_extent(fs_info, head->bytenr,
head->num_bytes, 1);
if (head->is_data) {
ret = btrfs_del_csums(trans, fs_info, head->bytenr,
head->num_bytes);
}
}
btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
trace_run_delayed_ref_head(fs_info, head, 0);
btrfs_delayed_ref_unlock(head);
btrfs_put_delayed_ref_head(head);
return 0;
}
static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
struct btrfs_trans_handle *trans)
{
struct btrfs_delayed_ref_root *delayed_refs =
&trans->transaction->delayed_refs;
struct btrfs_delayed_ref_head *head = NULL;
int ret;
spin_lock(&delayed_refs->lock);
head = btrfs_select_ref_head(delayed_refs);
if (!head) {
spin_unlock(&delayed_refs->lock);
return head;
}
/*
* Grab the lock that says we are going to process all the refs for
* this head
*/
ret = btrfs_delayed_ref_lock(delayed_refs, head);
spin_unlock(&delayed_refs->lock);
/*
* We may have dropped the spin lock to get the head mutex lock, and
* that might have given someone else time to free the head. If that's
* true, it has been removed from our list and we can move on.
*/
if (ret == -EAGAIN)
head = ERR_PTR(-EAGAIN);
return head;
}
static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *locked_ref,
unsigned long *run_refs)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_extent_op *extent_op;
struct btrfs_delayed_ref_node *ref;
int must_insert_reserved = 0;
int ret;
delayed_refs = &trans->transaction->delayed_refs;
lockdep_assert_held(&locked_ref->mutex);
lockdep_assert_held(&locked_ref->lock);
while ((ref = select_delayed_ref(locked_ref))) {
if (ref->seq &&
btrfs_check_delayed_seq(fs_info, ref->seq)) {
spin_unlock(&locked_ref->lock);
unselect_delayed_ref_head(delayed_refs, locked_ref);
return -EAGAIN;
}
(*run_refs)++;
ref->in_tree = 0;
rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
/*
* When we play the delayed ref, also correct the ref_mod on
* head
*/
switch (ref->action) {
case BTRFS_ADD_DELAYED_REF:
case BTRFS_ADD_DELAYED_EXTENT:
locked_ref->ref_mod -= ref->ref_mod;
break;
case BTRFS_DROP_DELAYED_REF:
locked_ref->ref_mod += ref->ref_mod;
break;
default:
WARN_ON(1);
}
atomic_dec(&delayed_refs->num_entries);
/*
* Record the must_insert_reserved flag before we drop the
* spin lock.
*/
must_insert_reserved = locked_ref->must_insert_reserved;
locked_ref->must_insert_reserved = 0;
extent_op = locked_ref->extent_op;
locked_ref->extent_op = NULL;
spin_unlock(&locked_ref->lock);
ret = run_one_delayed_ref(trans, ref, extent_op,
must_insert_reserved);
btrfs_free_delayed_extent_op(extent_op);
if (ret) {
unselect_delayed_ref_head(delayed_refs, locked_ref);
btrfs_put_delayed_ref(ref);
btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
ret);
return ret;
}
btrfs_put_delayed_ref(ref);
cond_resched();
spin_lock(&locked_ref->lock);
btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
}
return 0;
}
/*
* Returns 0 on success or if called with an already aborted transaction.
* Returns -ENOMEM or -EIO on failure and will abort the transaction.
*/
static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
unsigned long nr)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *locked_ref = NULL;
ktime_t start = ktime_get();
int ret;
unsigned long count = 0;
unsigned long actual_count = 0;
delayed_refs = &trans->transaction->delayed_refs;
do {
if (!locked_ref) {
locked_ref = btrfs_obtain_ref_head(trans);
if (IS_ERR_OR_NULL(locked_ref)) {
if (PTR_ERR(locked_ref) == -EAGAIN) {
continue;
} else {
break;
}
}
count++;
}
/*
* We need to try and merge add/drops of the same ref since we
* can run into issues with relocate dropping the implicit ref
* and then it being added back again before the drop can
* finish. If we merged anything we need to re-loop so we can
* get a good ref.
* Or we can get node references of the same type that weren't
* merged when created due to bumps in the tree mod seq, and
* we need to merge them to prevent adding an inline extent
* backref before dropping it (triggering a BUG_ON at
* insert_inline_extent_backref()).
*/
spin_lock(&locked_ref->lock);
btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
&actual_count);
if (ret < 0 && ret != -EAGAIN) {
/*
* Error, btrfs_run_delayed_refs_for_head already
* unlocked everything so just bail out
*/
return ret;
} else if (!ret) {
/*
* Success, perform the usual cleanup of a processed
* head
*/
ret = cleanup_ref_head(trans, locked_ref);
if (ret > 0 ) {
/* We dropped our lock, we need to loop. */
ret = 0;
continue;
} else if (ret) {
return ret;
}
}
/*
* Either success case or btrfs_run_delayed_refs_for_head
* returned -EAGAIN, meaning we need to select another head
*/
locked_ref = NULL;
cond_resched();
} while ((nr != -1 && count < nr) || locked_ref);
/*
* We don't want to include ref heads since we can have empty ref heads
* and those will drastically skew our runtime down since we just do
* accounting, no actual extent tree updates.
*/
if (actual_count > 0) {
u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
u64 avg;
/*
* We weigh the current average higher than our current runtime
* to avoid large swings in the average.
*/
spin_lock(&delayed_refs->lock);
avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
spin_unlock(&delayed_refs->lock);
}
return 0;
}
#ifdef SCRAMBLE_DELAYED_REFS
/*
* Normally delayed refs get processed in ascending bytenr order. This
* correlates in most cases to the order added. To expose dependencies on this
* order, we start to process the tree in the middle instead of the beginning
*/
static u64 find_middle(struct rb_root *root)
{
struct rb_node *n = root->rb_node;
struct btrfs_delayed_ref_node *entry;
int alt = 1;
u64 middle;
u64 first = 0, last = 0;
n = rb_first(root);
if (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
first = entry->bytenr;
}
n = rb_last(root);
if (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
last = entry->bytenr;
}
n = root->rb_node;
while (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
WARN_ON(!entry->in_tree);
middle = entry->bytenr;
if (alt)
n = n->rb_left;
else
n = n->rb_right;
alt = 1 - alt;
}
return middle;
}
#endif
static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
{
u64 num_bytes;
num_bytes = heads * (sizeof(struct btrfs_extent_item) +
sizeof(struct btrfs_extent_inline_ref));
if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
num_bytes += heads * sizeof(struct btrfs_tree_block_info);
/*
* We don't ever fill up leaves all the way so multiply by 2 just to be
* closer to what we're really going to want to use.
*/
return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
}
/*
* Takes the number of bytes to be csumm'ed and figures out how many leaves it
* would require to store the csums for that many bytes.
*/
u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
{
u64 csum_size;
u64 num_csums_per_leaf;
u64 num_csums;
csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
num_csums_per_leaf = div64_u64(csum_size,
(u64)btrfs_super_csum_size(fs_info->super_copy));
num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
num_csums += num_csums_per_leaf - 1;
num_csums = div64_u64(num_csums, num_csums_per_leaf);
return num_csums;
}
/*
* this starts processing the delayed reference count updates and
* extent insertions we have queued up so far. count can be
* 0, which means to process everything in the tree at the start
* of the run (but not newly added entries), or it can be some target
* number you'd like to process.
*
* Returns 0 on success or if called with an aborted transaction
* Returns <0 on error and aborts the transaction
*/
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
unsigned long count)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct rb_node *node;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *head;
int ret;
int run_all = count == (unsigned long)-1;
/* We'll clean this up in btrfs_cleanup_transaction */
if (trans->aborted)
return 0;
if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
return 0;
delayed_refs = &trans->transaction->delayed_refs;
if (count == 0)
count = atomic_read(&delayed_refs->num_entries) * 2;
again:
#ifdef SCRAMBLE_DELAYED_REFS
delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
#endif
ret = __btrfs_run_delayed_refs(trans, count);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
return ret;
}
if (run_all) {
btrfs_create_pending_block_groups(trans);
spin_lock(&delayed_refs->lock);
node = rb_first_cached(&delayed_refs->href_root);
if (!node) {
spin_unlock(&delayed_refs->lock);
goto out;
}
head = rb_entry(node, struct btrfs_delayed_ref_head,
href_node);
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
/* Mutex was contended, block until it's released and retry. */
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
cond_resched();
goto again;
}
out:
return 0;
}
int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, u64 flags,
int level, int is_data)
{
struct btrfs_delayed_extent_op *extent_op;
int ret;
extent_op = btrfs_alloc_delayed_extent_op();
if (!extent_op)
return -ENOMEM;
extent_op->flags_to_set = flags;
extent_op->update_flags = true;
extent_op->update_key = false;
extent_op->is_data = is_data ? true : false;
extent_op->level = level;
ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
if (ret)
btrfs_free_delayed_extent_op(extent_op);
return ret;
}
static noinline int check_delayed_ref(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset, u64 bytenr)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_node *ref;
struct btrfs_delayed_data_ref *data_ref;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_transaction *cur_trans;
struct rb_node *node;
int ret = 0;
spin_lock(&root->fs_info->trans_lock);
cur_trans = root->fs_info->running_transaction;
if (cur_trans)
refcount_inc(&cur_trans->use_count);
spin_unlock(&root->fs_info->trans_lock);
if (!cur_trans)
return 0;
delayed_refs = &cur_trans->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head) {
spin_unlock(&delayed_refs->lock);
btrfs_put_transaction(cur_trans);
return 0;
}
if (!mutex_trylock(&head->mutex)) {
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's released and let
* caller try again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
btrfs_put_transaction(cur_trans);
return -EAGAIN;
}
spin_unlock(&delayed_refs->lock);
spin_lock(&head->lock);
/*
* XXX: We should replace this with a proper search function in the
* future.
*/
for (node = rb_first_cached(&head->ref_tree); node;
node = rb_next(node)) {
ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
/* If it's a shared ref we know a cross reference exists */
if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
ret = 1;
break;
}
data_ref = btrfs_delayed_node_to_data_ref(ref);
/*
* If our ref doesn't match the one we're currently looking at
* then we have a cross reference.
*/
if (data_ref->root != root->root_key.objectid ||
data_ref->objectid != objectid ||
data_ref->offset != offset) {
ret = 1;
break;
}
}
spin_unlock(&head->lock);
mutex_unlock(&head->mutex);
btrfs_put_transaction(cur_trans);
return ret;
}
static noinline int check_committed_ref(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset, u64 bytenr)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *extent_root = fs_info->extent_root;
struct extent_buffer *leaf;
struct btrfs_extent_data_ref *ref;
struct btrfs_extent_inline_ref *iref;
struct btrfs_extent_item *ei;
struct btrfs_key key;
u32 item_size;
int type;
int ret;
key.objectid = bytenr;
key.offset = (u64)-1;
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0); /* Corruption */
ret = -ENOENT;
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
goto out;
ret = 1;
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
if (item_size != sizeof(*ei) +
btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
goto out;
if (btrfs_extent_generation(leaf, ei) <=
btrfs_root_last_snapshot(&root->root_item))
goto out;
iref = (struct btrfs_extent_inline_ref *)(ei + 1);
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
if (type != BTRFS_EXTENT_DATA_REF_KEY)
goto out;
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (btrfs_extent_refs(leaf, ei) !=
btrfs_extent_data_ref_count(leaf, ref) ||
btrfs_extent_data_ref_root(leaf, ref) !=
root->root_key.objectid ||
btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
btrfs_extent_data_ref_offset(leaf, ref) != offset)
goto out;
ret = 0;
out:
return ret;
}
int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
u64 bytenr)
{
struct btrfs_path *path;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
do {
ret = check_committed_ref(root, path, objectid,
offset, bytenr);
if (ret && ret != -ENOENT)
goto out;
ret = check_delayed_ref(root, path, objectid, offset, bytenr);
} while (ret == -EAGAIN);
out:
btrfs_free_path(path);
if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
WARN_ON(ret > 0);
return ret;
}
static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
int full_backref, int inc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 num_bytes;
u64 parent;
u64 ref_root;
u32 nritems;
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
struct btrfs_ref generic_ref = { 0 };
bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
int i;
int action;
int level;
int ret = 0;
if (btrfs_is_testing(fs_info))
return 0;
ref_root = btrfs_header_owner(buf);
nritems = btrfs_header_nritems(buf);
level = btrfs_header_level(buf);
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
return 0;
if (full_backref)
parent = buf->start;
else
parent = 0;
if (inc)
action = BTRFS_ADD_DELAYED_REF;
else
action = BTRFS_DROP_DELAYED_REF;
for (i = 0; i < nritems; i++) {
if (level == 0) {
btrfs_item_key_to_cpu(buf, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(buf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(buf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
if (bytenr == 0)
continue;
num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
key.offset -= btrfs_file_extent_offset(buf, fi);
btrfs_init_generic_ref(&generic_ref, action, bytenr,
num_bytes, parent);
generic_ref.real_root = root->root_key.objectid;
btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
key.offset);
generic_ref.skip_qgroup = for_reloc;
if (inc)
ret = btrfs_inc_extent_ref(trans, &generic_ref);
else
ret = btrfs_free_extent(trans, &generic_ref);
if (ret)
goto fail;
} else {
bytenr = btrfs_node_blockptr(buf, i);
num_bytes = fs_info->nodesize;
btrfs_init_generic_ref(&generic_ref, action, bytenr,
num_bytes, parent);
generic_ref.real_root = root->root_key.objectid;
btrfs_init_tree_ref(&generic_ref, level - 1, ref_root);
generic_ref.skip_qgroup = for_reloc;
if (inc)
ret = btrfs_inc_extent_ref(trans, &generic_ref);
else
ret = btrfs_free_extent(trans, &generic_ref);
if (ret)
goto fail;
}
}
return 0;
fail:
return ret;
}
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int full_backref)
{
return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
}
int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int full_backref)
{
return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
}
static int write_one_cache_group(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_root *extent_root = fs_info->extent_root;
unsigned long bi;
struct extent_buffer *leaf;
ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto fail;
}
leaf = path->nodes[0];
bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
btrfs_mark_buffer_dirty(leaf);
fail:
btrfs_release_path(path);
return ret;
}
static int cache_save_setup(struct btrfs_block_group_cache *block_group,
struct btrfs_trans_handle *trans,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_root *root = fs_info->tree_root;
struct inode *inode = NULL;
struct extent_changeset *data_reserved = NULL;
u64 alloc_hint = 0;
int dcs = BTRFS_DC_ERROR;
u64 num_pages = 0;
int retries = 0;
int ret = 0;
/*
* If this block group is smaller than 100 megs don't bother caching the
* block group.
*/
if (block_group->key.offset < (100 * SZ_1M)) {
spin_lock(&block_group->lock);
block_group->disk_cache_state = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);
return 0;
}
if (trans->aborted)
return 0;
again:
inode = lookup_free_space_inode(block_group, path);
if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
ret = PTR_ERR(inode);
btrfs_release_path(path);
goto out;
}
if (IS_ERR(inode)) {
BUG_ON(retries);
retries++;
if (block_group->ro)
goto out_free;
ret = create_free_space_inode(trans, block_group, path);
if (ret)
goto out_free;
goto again;
}
/*
* We want to set the generation to 0, that way if anything goes wrong
* from here on out we know not to trust this cache when we load up next
* time.
*/
BTRFS_I(inode)->generation = 0;
ret = btrfs_update_inode(trans, root, inode);
if (ret) {
/*
* So theoretically we could recover from this, simply set the
* super cache generation to 0 so we know to invalidate the
* cache, but then we'd have to keep track of the block groups
* that fail this way so we know we _have_ to reset this cache
* before the next commit or risk reading stale cache. So to
* limit our exposure to horrible edge cases lets just abort the
* transaction, this only happens in really bad situations
* anyway.
*/
btrfs_abort_transaction(trans, ret);
goto out_put;
}
WARN_ON(ret);
/* We've already setup this transaction, go ahead and exit */
if (block_group->cache_generation == trans->transid &&
i_size_read(inode)) {
dcs = BTRFS_DC_SETUP;
goto out_put;
}
if (i_size_read(inode) > 0) {
ret = btrfs_check_trunc_cache_free_space(fs_info,
&fs_info->global_block_rsv);
if (ret)
goto out_put;
ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
if (ret)
goto out_put;
}
spin_lock(&block_group->lock);
if (block_group->cached != BTRFS_CACHE_FINISHED ||
!btrfs_test_opt(fs_info, SPACE_CACHE)) {
/*
* don't bother trying to write stuff out _if_
* a) we're not cached,
* b) we're with nospace_cache mount option,
* c) we're with v2 space_cache (FREE_SPACE_TREE).
*/
dcs = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);
goto out_put;
}
spin_unlock(&block_group->lock);
/*
* We hit an ENOSPC when setting up the cache in this transaction, just
* skip doing the setup, we've already cleared the cache so we're safe.
*/
if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
ret = -ENOSPC;
goto out_put;
}
/*
* Try to preallocate enough space based on how big the block group is.
* Keep in mind this has to include any pinned space which could end up
* taking up quite a bit since it's not folded into the other space
* cache.
*/
num_pages = div_u64(block_group->key.offset, SZ_256M);
if (!num_pages)
num_pages = 1;
num_pages *= 16;
num_pages *= PAGE_SIZE;
ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
if (ret)
goto out_put;
ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
num_pages, num_pages,
&alloc_hint);
/*
* Our cache requires contiguous chunks so that we don't modify a bunch
* of metadata or split extents when writing the cache out, which means
* we can enospc if we are heavily fragmented in addition to just normal
* out of space conditions. So if we hit this just skip setting up any
* other block groups for this transaction, maybe we'll unpin enough
* space the next time around.
*/
if (!ret)
dcs = BTRFS_DC_SETUP;
else if (ret == -ENOSPC)
set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
out_put:
iput(inode);
out_free:
btrfs_release_path(path);
out:
spin_lock(&block_group->lock);
if (!ret && dcs == BTRFS_DC_SETUP)
block_group->cache_generation = trans->transid;
block_group->disk_cache_state = dcs;
spin_unlock(&block_group->lock);
extent_changeset_free(data_reserved);
return ret;
}
int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache, *tmp;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_path *path;
if (list_empty(&cur_trans->dirty_bgs) ||
!btrfs_test_opt(fs_info, SPACE_CACHE))
return 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/* Could add new block groups, use _safe just in case */
list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
dirty_list) {
if (cache->disk_cache_state == BTRFS_DC_CLEAR)
cache_save_setup(cache, trans, path);
}
btrfs_free_path(path);
return 0;
}
/*
* transaction commit does final block group cache writeback during a
* critical section where nothing is allowed to change the FS. This is
* required in order for the cache to actually match the block group,
* but can introduce a lot of latency into the commit.
*
* So, btrfs_start_dirty_block_groups is here to kick off block group
* cache IO. There's a chance we'll have to redo some of it if the
* block group changes again during the commit, but it greatly reduces
* the commit latency by getting rid of the easy block groups while
* we're still allowing others to join the commit.
*/
int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
struct btrfs_transaction *cur_trans = trans->transaction;
int ret = 0;
int should_put;
struct btrfs_path *path = NULL;
LIST_HEAD(dirty);
struct list_head *io = &cur_trans->io_bgs;
int num_started = 0;
int loops = 0;
spin_lock(&cur_trans->dirty_bgs_lock);
if (list_empty(&cur_trans->dirty_bgs)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
return 0;
}
list_splice_init(&cur_trans->dirty_bgs, &dirty);
spin_unlock(&cur_trans->dirty_bgs_lock);
again:
/*
* make sure all the block groups on our dirty list actually
* exist
*/
btrfs_create_pending_block_groups(trans);
if (!path) {
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
}
/*
* cache_write_mutex is here only to save us from balance or automatic
* removal of empty block groups deleting this block group while we are
* writing out the cache
*/
mutex_lock(&trans->transaction->cache_write_mutex);
while (!list_empty(&dirty)) {
bool drop_reserve = true;
cache = list_first_entry(&dirty,
struct btrfs_block_group_cache,
dirty_list);
/*
* this can happen if something re-dirties a block
* group that is already under IO. Just wait for it to
* finish and then do it all again
*/
if (!list_empty(&cache->io_list)) {
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
}
/*
* btrfs_wait_cache_io uses the cache->dirty_list to decide
* if it should update the cache_state. Don't delete
* until after we wait.
*
* Since we're not running in the commit critical section
* we need the dirty_bgs_lock to protect from update_block_group
*/
spin_lock(&cur_trans->dirty_bgs_lock);
list_del_init(&cache->dirty_list);
spin_unlock(&cur_trans->dirty_bgs_lock);
should_put = 1;
cache_save_setup(cache, trans, path);
if (cache->disk_cache_state == BTRFS_DC_SETUP) {
cache->io_ctl.inode = NULL;
ret = btrfs_write_out_cache(trans, cache, path);
if (ret == 0 && cache->io_ctl.inode) {
num_started++;
should_put = 0;
/*
* The cache_write_mutex is protecting the
* io_list, also refer to the definition of
* btrfs_transaction::io_bgs for more details
*/
list_add_tail(&cache->io_list, io);
} else {
/*
* if we failed to write the cache, the
* generation will be bad and life goes on
*/
ret = 0;
}
}
if (!ret) {
ret = write_one_cache_group(trans, path, cache);
/*
* Our block group might still be attached to the list
* of new block groups in the transaction handle of some
* other task (struct btrfs_trans_handle->new_bgs). This
* means its block group item isn't yet in the extent
* tree. If this happens ignore the error, as we will
* try again later in the critical section of the
* transaction commit.
*/
if (ret == -ENOENT) {
ret = 0;
spin_lock(&cur_trans->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
list_add_tail(&cache->dirty_list,
&cur_trans->dirty_bgs);
btrfs_get_block_group(cache);
drop_reserve = false;
}
spin_unlock(&cur_trans->dirty_bgs_lock);
} else if (ret) {
btrfs_abort_transaction(trans, ret);
}
}
/* if it's not on the io list, we need to put the block group */
if (should_put)
btrfs_put_block_group(cache);
if (drop_reserve)
btrfs_delayed_refs_rsv_release(fs_info, 1);
if (ret)
break;
/*
* Avoid blocking other tasks for too long. It might even save
* us from writing caches for block groups that are going to be
* removed.
*/
mutex_unlock(&trans->transaction->cache_write_mutex);
mutex_lock(&trans->transaction->cache_write_mutex);
}
mutex_unlock(&trans->transaction->cache_write_mutex);
/*
* go through delayed refs for all the stuff we've just kicked off
* and then loop back (just once)
*/
ret = btrfs_run_delayed_refs(trans, 0);
if (!ret && loops == 0) {
loops++;
spin_lock(&cur_trans->dirty_bgs_lock);
list_splice_init(&cur_trans->dirty_bgs, &dirty);
/*
* dirty_bgs_lock protects us from concurrent block group
* deletes too (not just cache_write_mutex).
*/
if (!list_empty(&dirty)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
goto again;
}
spin_unlock(&cur_trans->dirty_bgs_lock);
} else if (ret < 0) {
btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
}
btrfs_free_path(path);
return ret;
}
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
struct btrfs_transaction *cur_trans = trans->transaction;
int ret = 0;
int should_put;
struct btrfs_path *path;
struct list_head *io = &cur_trans->io_bgs;
int num_started = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/*
* Even though we are in the critical section of the transaction commit,
* we can still have concurrent tasks adding elements to this
* transaction's list of dirty block groups. These tasks correspond to
* endio free space workers started when writeback finishes for a
* space cache, which run inode.c:btrfs_finish_ordered_io(), and can
* allocate new block groups as a result of COWing nodes of the root
* tree when updating the free space inode. The writeback for the space
* caches is triggered by an earlier call to
* btrfs_start_dirty_block_groups() and iterations of the following
* loop.
* Also we want to do the cache_save_setup first and then run the
* delayed refs to make sure we have the best chance at doing this all
* in one shot.
*/
spin_lock(&cur_trans->dirty_bgs_lock);
while (!list_empty(&cur_trans->dirty_bgs)) {
cache = list_first_entry(&cur_trans->dirty_bgs,
struct btrfs_block_group_cache,
dirty_list);
/*
* this can happen if cache_save_setup re-dirties a block
* group that is already under IO. Just wait for it to
* finish and then do it all again
*/
if (!list_empty(&cache->io_list)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
spin_lock(&cur_trans->dirty_bgs_lock);
}
/*
* don't remove from the dirty list until after we've waited
* on any pending IO
*/
list_del_init(&cache->dirty_list);
spin_unlock(&cur_trans->dirty_bgs_lock);
should_put = 1;
cache_save_setup(cache, trans, path);
if (!ret)
ret = btrfs_run_delayed_refs(trans,
(unsigned long) -1);
if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
cache->io_ctl.inode = NULL;
ret = btrfs_write_out_cache(trans, cache, path);
if (ret == 0 && cache->io_ctl.inode) {
num_started++;
should_put = 0;
list_add_tail(&cache->io_list, io);
} else {
/*
* if we failed to write the cache, the
* generation will be bad and life goes on
*/
ret = 0;
}
}
if (!ret) {
ret = write_one_cache_group(trans, path, cache);
/*
* One of the free space endio workers might have
* created a new block group while updating a free space
* cache's inode (at inode.c:btrfs_finish_ordered_io())
* and hasn't released its transaction handle yet, in
* which case the new block group is still attached to
* its transaction handle and its creation has not
* finished yet (no block group item in the extent tree
* yet, etc). If this is the case, wait for all free
* space endio workers to finish and retry. This is a
* a very rare case so no need for a more efficient and
* complex approach.
*/
if (ret == -ENOENT) {
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
ret = write_one_cache_group(trans, path, cache);
}
if (ret)
btrfs_abort_transaction(trans, ret);
}
/* if its not on the io list, we need to put the block group */
if (should_put)
btrfs_put_block_group(cache);
btrfs_delayed_refs_rsv_release(fs_info, 1);
spin_lock(&cur_trans->dirty_bgs_lock);
}
spin_unlock(&cur_trans->dirty_bgs_lock);
/*
* Refer to the definition of io_bgs member for details why it's safe
* to use it without any locking
*/
while (!list_empty(io)) {
cache = list_first_entry(io, struct btrfs_block_group_cache,
io_list);
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
}
btrfs_free_path(path);
return ret;
}
int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
{
struct btrfs_block_group_cache *block_group;
int readonly = 0;
block_group = btrfs_lookup_block_group(fs_info, bytenr);
if (!block_group || block_group->ro)
readonly = 1;
if (block_group)
btrfs_put_block_group(block_group);
return readonly;
}
static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = chunk_to_extended(flags) &
BTRFS_EXTENDED_PROFILE_MASK;
write_seqlock(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
fs_info->avail_data_alloc_bits |= extra_flags;
if (flags & BTRFS_BLOCK_GROUP_METADATA)
fs_info->avail_metadata_alloc_bits |= extra_flags;
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
fs_info->avail_system_alloc_bits |= extra_flags;
write_sequnlock(&fs_info->profiles_lock);
}
/*
* returns target flags in extended format or 0 if restripe for this
* chunk_type is not in progress
*
* should be called with balance_lock held
*/
static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
{
struct btrfs_balance_control *bctl = fs_info->balance_ctl;
u64 target = 0;
if (!bctl)
return 0;
if (flags & BTRFS_BLOCK_GROUP_DATA &&
bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
} else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
} else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
}
return target;
}
/*
* @flags: available profiles in extended format (see ctree.h)
*
* Returns reduced profile in chunk format. If profile changing is in
* progress (either running or paused) picks the target profile (if it's
* already available), otherwise falls back to plain reducing.
*/
static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 num_devices = fs_info->fs_devices->rw_devices;
u64 target;
u64 raid_type;
u64 allowed = 0;
/*
* see if restripe for this chunk_type is in progress, if so
* try to reduce to the target profile
*/
spin_lock(&fs_info->balance_lock);
target = get_restripe_target(fs_info, flags);
if (target) {
/* pick target profile only if it's already available */
if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
spin_unlock(&fs_info->balance_lock);
return extended_to_chunk(target);
}
}
spin_unlock(&fs_info->balance_lock);
/* First, mask out the RAID levels which aren't possible */
for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
if (num_devices >= btrfs_raid_array[raid_type].devs_min)
allowed |= btrfs_raid_array[raid_type].bg_flag;
}
allowed &= flags;
if (allowed & BTRFS_BLOCK_GROUP_RAID6)
allowed = BTRFS_BLOCK_GROUP_RAID6;
else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
allowed = BTRFS_BLOCK_GROUP_RAID5;
else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
allowed = BTRFS_BLOCK_GROUP_RAID10;
else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
allowed = BTRFS_BLOCK_GROUP_RAID1;
else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
allowed = BTRFS_BLOCK_GROUP_RAID0;
flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
return extended_to_chunk(flags | allowed);
}
static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
{
unsigned seq;
u64 flags;
do {
flags = orig_flags;
seq = read_seqbegin(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
flags |= fs_info->avail_data_alloc_bits;
else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
flags |= fs_info->avail_system_alloc_bits;
else if (flags & BTRFS_BLOCK_GROUP_METADATA)
flags |= fs_info->avail_metadata_alloc_bits;
} while (read_seqretry(&fs_info->profiles_lock, seq));
return btrfs_reduce_alloc_profile(fs_info, flags);
}
static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 flags;
u64 ret;
if (data)
flags = BTRFS_BLOCK_GROUP_DATA;
else if (root == fs_info->chunk_root)
flags = BTRFS_BLOCK_GROUP_SYSTEM;
else
flags = BTRFS_BLOCK_GROUP_METADATA;
ret = get_alloc_profile(fs_info, flags);
return ret;
}
u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
{
return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
}
u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
{
return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
}
u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
{
return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
}
static void force_metadata_allocation(struct btrfs_fs_info *info)
{
struct list_head *head = &info->space_info;
struct btrfs_space_info *found;
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
found->force_alloc = CHUNK_ALLOC_FORCE;
}
rcu_read_unlock();
}
static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *sinfo, int force)
{
u64 bytes_used = btrfs_space_info_used(sinfo, false);
u64 thresh;
if (force == CHUNK_ALLOC_FORCE)
return 1;
/*
* in limited mode, we want to have some free space up to
* about 1% of the FS size.
*/
if (force == CHUNK_ALLOC_LIMITED) {
thresh = btrfs_super_total_bytes(fs_info->super_copy);
thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
if (sinfo->total_bytes - bytes_used < thresh)
return 1;
}
if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
return 0;
return 1;
}
static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
{
u64 num_dev;
num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
if (!num_dev)
num_dev = fs_info->fs_devices->rw_devices;
return num_dev;
}
/*
* If @is_allocation is true, reserve space in the system space info necessary
* for allocating a chunk, otherwise if it's false, reserve space necessary for
* removing a chunk.
*/
void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_space_info *info;
u64 left;
u64 thresh;
int ret = 0;
u64 num_devs;
/*
* Needed because we can end up allocating a system chunk and for an
* atomic and race free space reservation in the chunk block reserve.
*/
lockdep_assert_held(&fs_info->chunk_mutex);
info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
spin_lock(&info->lock);
left = info->total_bytes - btrfs_space_info_used(info, true);
spin_unlock(&info->lock);
num_devs = get_profile_num_devs(fs_info, type);
/* num_devs device items to update and 1 chunk item to add or remove */
thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
btrfs_calc_trans_metadata_size(fs_info, 1);
if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
left, thresh, type);
btrfs_dump_space_info(fs_info, info, 0, 0);
}
if (left < thresh) {
u64 flags = btrfs_system_alloc_profile(fs_info);
/*
* Ignore failure to create system chunk. We might end up not
* needing it, as we might not need to COW all nodes/leafs from
* the paths we visit in the chunk tree (they were already COWed
* or created in the current transaction for example).
*/
ret = btrfs_alloc_chunk(trans, flags);
}
if (!ret) {
ret = btrfs_block_rsv_add(fs_info->chunk_root,
&fs_info->chunk_block_rsv,
thresh, BTRFS_RESERVE_NO_FLUSH);
if (!ret)
trans->chunk_bytes_reserved += thresh;
}
}
/*
* If force is CHUNK_ALLOC_FORCE:
* - return 1 if it successfully allocates a chunk,
* - return errors including -ENOSPC otherwise.
* If force is NOT CHUNK_ALLOC_FORCE:
* - return 0 if it doesn't need to allocate a new chunk,
* - return 1 if it successfully allocates a chunk,
* - return errors including -ENOSPC otherwise.
*/
int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
enum btrfs_chunk_alloc_enum force)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_space_info *space_info;
bool wait_for_alloc = false;
bool should_alloc = false;
int ret = 0;
/* Don't re-enter if we're already allocating a chunk */
if (trans->allocating_chunk)
return -ENOSPC;
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
do {
spin_lock(&space_info->lock);
if (force < space_info->force_alloc)
force = space_info->force_alloc;
should_alloc = should_alloc_chunk(fs_info, space_info, force);
if (space_info->full) {
/* No more free physical space */
if (should_alloc)
ret = -ENOSPC;
else
ret = 0;
spin_unlock(&space_info->lock);
return ret;
} else if (!should_alloc) {
spin_unlock(&space_info->lock);
return 0;
} else if (space_info->chunk_alloc) {
/*
* Someone is already allocating, so we need to block
* until this someone is finished and then loop to
* recheck if we should continue with our allocation
* attempt.
*/
wait_for_alloc = true;
spin_unlock(&space_info->lock);
mutex_lock(&fs_info->chunk_mutex);
mutex_unlock(&fs_info->chunk_mutex);
} else {
/* Proceed with allocation */
space_info->chunk_alloc = 1;
wait_for_alloc = false;
spin_unlock(&space_info->lock);
}
cond_resched();
} while (wait_for_alloc);
mutex_lock(&fs_info->chunk_mutex);
trans->allocating_chunk = true;
/*
* If we have mixed data/metadata chunks we want to make sure we keep
* allocating mixed chunks instead of individual chunks.
*/
if (btrfs_mixed_space_info(space_info))
flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
/*
* if we're doing a data chunk, go ahead and make sure that
* we keep a reasonable number of metadata chunks allocated in the
* FS as well.
*/
if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
fs_info->data_chunk_allocations++;
if (!(fs_info->data_chunk_allocations %
fs_info->metadata_ratio))
force_metadata_allocation(fs_info);
}
/*
* Check if we have enough space in SYSTEM chunk because we may need
* to update devices.
*/
check_system_chunk(trans, flags);
ret = btrfs_alloc_chunk(trans, flags);
trans->allocating_chunk = false;
spin_lock(&space_info->lock);
if (ret < 0) {
if (ret == -ENOSPC)
space_info->full = 1;
else
goto out;
} else {
ret = 1;
space_info->max_extent_size = 0;
}
space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
out:
space_info->chunk_alloc = 0;
spin_unlock(&space_info->lock);
mutex_unlock(&fs_info->chunk_mutex);
/*
* When we allocate a new chunk we reserve space in the chunk block
* reserve to make sure we can COW nodes/leafs in the chunk tree or
* add new nodes/leafs to it if we end up needing to do it when
* inserting the chunk item and updating device items as part of the
* second phase of chunk allocation, performed by
* btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
* large number of new block groups to create in our transaction
* handle's new_bgs list to avoid exhausting the chunk block reserve
* in extreme cases - like having a single transaction create many new
* block groups when starting to write out the free space caches of all
* the block groups that were made dirty during the lifetime of the
* transaction.
*/
if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
btrfs_create_pending_block_groups(trans);
return ret;
}
static int update_block_group(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, int alloc)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_block_group_cache *cache = NULL;
u64 total = num_bytes;
u64 old_val;
u64 byte_in_group;
int factor;
int ret = 0;
/* block accounting for super block */
spin_lock(&info->delalloc_root_lock);
old_val = btrfs_super_bytes_used(info->super_copy);
if (alloc)
old_val += num_bytes;
else
old_val -= num_bytes;
btrfs_set_super_bytes_used(info->super_copy, old_val);
spin_unlock(&info->delalloc_root_lock);
while (total) {
cache = btrfs_lookup_block_group(info, bytenr);
if (!cache) {
ret = -ENOENT;
break;
}
factor = btrfs_bg_type_to_factor(cache->flags);
/*
* If this block group has free space cache written out, we
* need to make sure to load it if we are removing space. This
* is because we need the unpinning stage to actually add the
* space back to the block group, otherwise we will leak space.
*/
if (!alloc && cache->cached == BTRFS_CACHE_NO)
btrfs_cache_block_group(cache, 1);
byte_in_group = bytenr - cache->key.objectid;
WARN_ON(byte_in_group > cache->key.offset);
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
if (btrfs_test_opt(info, SPACE_CACHE) &&
cache->disk_cache_state < BTRFS_DC_CLEAR)
cache->disk_cache_state = BTRFS_DC_CLEAR;
old_val = btrfs_block_group_used(&cache->item);
num_bytes = min(total, cache->key.offset - byte_in_group);
if (alloc) {
old_val += num_bytes;
btrfs_set_block_group_used(&cache->item, old_val);
cache->reserved -= num_bytes;
cache->space_info->bytes_reserved -= num_bytes;
cache->space_info->bytes_used += num_bytes;
cache->space_info->disk_used += num_bytes * factor;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
} else {
old_val -= num_bytes;
btrfs_set_block_group_used(&cache->item, old_val);
cache->pinned += num_bytes;
btrfs_space_info_update_bytes_pinned(info,
cache->space_info, num_bytes);
cache->space_info->bytes_used -= num_bytes;
cache->space_info->disk_used -= num_bytes * factor;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
trace_btrfs_space_reservation(info, "pinned",
cache->space_info->flags,
num_bytes, 1);
percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
num_bytes,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
set_extent_dirty(info->pinned_extents,
bytenr, bytenr + num_bytes - 1,
GFP_NOFS | __GFP_NOFAIL);
}
spin_lock(&trans->transaction->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
list_add_tail(&cache->dirty_list,
&trans->transaction->dirty_bgs);
trans->delayed_ref_updates++;
btrfs_get_block_group(cache);
}
spin_unlock(&trans->transaction->dirty_bgs_lock);
/*
* No longer have used bytes in this block group, queue it for
* deletion. We do this after adding the block group to the
* dirty list to avoid races between cleaner kthread and space
* cache writeout.
*/
if (!alloc && old_val == 0)
btrfs_mark_bg_unused(cache);
btrfs_put_block_group(cache);
total -= num_bytes;
bytenr += num_bytes;
}
/* Modified block groups are accounted for in the delayed_refs_rsv. */
btrfs_update_delayed_refs_rsv(trans);
return ret;
}
static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
{
struct btrfs_block_group_cache *cache;
u64 bytenr;
spin_lock(&fs_info->block_group_cache_lock);
bytenr = fs_info->first_logical_byte;
spin_unlock(&fs_info->block_group_cache_lock);
if (bytenr < (u64)-1)
return bytenr;
cache = btrfs_lookup_first_block_group(fs_info, search_start);
if (!cache)
return 0;
bytenr = cache->key.objectid;
btrfs_put_block_group(cache);
return bytenr;
}
static int pin_down_extent(struct btrfs_block_group_cache *cache,
u64 bytenr, u64 num_bytes, int reserved)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
cache->pinned += num_bytes;
btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
num_bytes);
if (reserved) {
cache->reserved -= num_bytes;
cache->space_info->bytes_reserved -= num_bytes;
}
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
trace_btrfs_space_reservation(fs_info, "pinned",
cache->space_info->flags, num_bytes, 1);
percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
set_extent_dirty(fs_info->pinned_extents, bytenr,
bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
return 0;
}
/*
* this function must be called within transaction
*/
int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
u64 bytenr, u64 num_bytes, int reserved)
{
struct btrfs_block_group_cache *cache;
cache = btrfs_lookup_block_group(fs_info, bytenr);
BUG_ON(!cache); /* Logic error */
pin_down_extent(cache, bytenr, num_bytes, reserved);
btrfs_put_block_group(cache);
return 0;
}
/*
* this function must be called within transaction
*/
int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
u64 bytenr, u64 num_bytes)
{
struct btrfs_block_group_cache *cache;
int ret;
cache = btrfs_lookup_block_group(fs_info, bytenr);
if (!cache)
return -EINVAL;
/*
* pull in the free space cache (if any) so that our pin
* removes the free space from the cache. We have load_only set
* to one because the slow code to read in the free extents does check
* the pinned extents.
*/
btrfs_cache_block_group(cache, 1);
pin_down_extent(cache, bytenr, num_bytes, 0);
/* remove us from the free space cache (if we're there at all) */
ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
btrfs_put_block_group(cache);
return ret;
}
static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 num_bytes)
{
int ret;
struct btrfs_block_group_cache *block_group;
struct btrfs_caching_control *caching_ctl;
block_group = btrfs_lookup_block_group(fs_info, start);
if (!block_group)
return -EINVAL;
btrfs_cache_block_group(block_group, 0);
caching_ctl = btrfs_get_caching_control(block_group);
if (!caching_ctl) {
/* Logic error */
BUG_ON(!btrfs_block_group_cache_done(block_group));
ret = btrfs_remove_free_space(block_group, start, num_bytes);
} else {
mutex_lock(&caching_ctl->mutex);
if (start >= caching_ctl->progress) {
ret = btrfs_add_excluded_extent(fs_info, start,
num_bytes);
} else if (start + num_bytes <= caching_ctl->progress) {
ret = btrfs_remove_free_space(block_group,
start, num_bytes);
} else {
num_bytes = caching_ctl->progress - start;
ret = btrfs_remove_free_space(block_group,
start, num_bytes);
if (ret)
goto out_lock;
num_bytes = (start + num_bytes) -
caching_ctl->progress;
start = caching_ctl->progress;
ret = btrfs_add_excluded_extent(fs_info, start,
num_bytes);
}
out_lock:
mutex_unlock(&caching_ctl->mutex);
btrfs_put_caching_control(caching_ctl);
}
btrfs_put_block_group(block_group);
return ret;
}
int btrfs_exclude_logged_extents(struct extent_buffer *eb)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct btrfs_file_extent_item *item;
struct btrfs_key key;
int found_type;
int i;
int ret = 0;
if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
return 0;
for (i = 0; i < btrfs_header_nritems(eb); i++) {
btrfs_item_key_to_cpu(eb, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(eb, item);
if (found_type == BTRFS_FILE_EXTENT_INLINE)
continue;
if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
continue;
key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
if (ret)
break;
}
return ret;
}
static void
btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
{
atomic_inc(&bg->reservations);
}
/**
* btrfs_add_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @ram_bytes: The number of bytes of file content, and will be same to
* @num_bytes except for the compress path.
* @num_bytes: The number of bytes in question
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by the allocator when it reserves space. If this is a
* reservation and the block group has become read only we cannot make the
* reservation and return -EAGAIN, otherwise this function always succeeds.
*/
static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 ram_bytes, u64 num_bytes, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
int ret = 0;
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (cache->ro) {
ret = -EAGAIN;
} else {
cache->reserved += num_bytes;
space_info->bytes_reserved += num_bytes;
btrfs_space_info_update_bytes_may_use(cache->fs_info,
space_info, -ram_bytes);
if (delalloc)
cache->delalloc_bytes += num_bytes;
}
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
return ret;
}
/**
* btrfs_free_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @num_bytes: The number of bytes in question
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by somebody who is freeing space that was never actually used
* on disk. For example if you reserve some space for a new leaf in transaction
* A and before transaction A commits you free that leaf, you call this with
* reserve set to 0 in order to clear the reservation.
*/
static void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (cache->ro)
space_info->bytes_readonly += num_bytes;
cache->reserved -= num_bytes;
space_info->bytes_reserved -= num_bytes;
space_info->max_extent_size = 0;
if (delalloc)
cache->delalloc_bytes -= num_bytes;
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
}
void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
{
struct btrfs_caching_control *next;
struct btrfs_caching_control *caching_ctl;
struct btrfs_block_group_cache *cache;
down_write(&fs_info->commit_root_sem);
list_for_each_entry_safe(caching_ctl, next,
&fs_info->caching_block_groups, list) {
cache = caching_ctl->block_group;
if (btrfs_block_group_cache_done(cache)) {
cache->last_byte_to_unpin = (u64)-1;
list_del_init(&caching_ctl->list);
btrfs_put_caching_control(caching_ctl);
} else {
cache->last_byte_to_unpin = caching_ctl->progress;
}
}
if (fs_info->pinned_extents == &fs_info->freed_extents[0])
fs_info->pinned_extents = &fs_info->freed_extents[1];
else
fs_info->pinned_extents = &fs_info->freed_extents[0];
up_write(&fs_info->commit_root_sem);
btrfs_update_global_block_rsv(fs_info);
}
/*
* Returns the free cluster for the given space info and sets empty_cluster to
* what it should be based on the mount options.
*/
static struct btrfs_free_cluster *
fetch_cluster_info(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *space_info, u64 *empty_cluster)
{
struct btrfs_free_cluster *ret = NULL;
*empty_cluster = 0;
if (btrfs_mixed_space_info(space_info))
return ret;
if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
ret = &fs_info->meta_alloc_cluster;
if (btrfs_test_opt(fs_info, SSD))
*empty_cluster = SZ_2M;
else
*empty_cluster = SZ_64K;
} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
btrfs_test_opt(fs_info, SSD_SPREAD)) {
*empty_cluster = SZ_2M;
ret = &fs_info->data_alloc_cluster;
}
return ret;
}
static int unpin_extent_range(struct btrfs_fs_info *fs_info,
u64 start, u64 end,
const bool return_free_space)
{
struct btrfs_block_group_cache *cache = NULL;
struct btrfs_space_info *space_info;
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
struct btrfs_free_cluster *cluster = NULL;
u64 len;
u64 total_unpinned = 0;
u64 empty_cluster = 0;
bool readonly;
while (start <= end) {
readonly = false;
if (!cache ||
start >= cache->key.objectid + cache->key.offset) {
if (cache)
btrfs_put_block_group(cache);
total_unpinned = 0;
cache = btrfs_lookup_block_group(fs_info, start);
BUG_ON(!cache); /* Logic error */
cluster = fetch_cluster_info(fs_info,
cache->space_info,
&empty_cluster);
empty_cluster <<= 1;
}
len = cache->key.objectid + cache->key.offset - start;
len = min(len, end + 1 - start);
if (start < cache->last_byte_to_unpin) {
len = min(len, cache->last_byte_to_unpin - start);
if (return_free_space)
btrfs_add_free_space(cache, start, len);
}
start += len;
total_unpinned += len;
space_info = cache->space_info;
/*
* If this space cluster has been marked as fragmented and we've
* unpinned enough in this block group to potentially allow a
* cluster to be created inside of it go ahead and clear the
* fragmented check.
*/
if (cluster && cluster->fragmented &&
total_unpinned > empty_cluster) {
spin_lock(&cluster->lock);
cluster->fragmented = 0;
spin_unlock(&cluster->lock);
}
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
cache->pinned -= len;
btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
trace_btrfs_space_reservation(fs_info, "pinned",
space_info->flags, len, 0);
space_info->max_extent_size = 0;
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
if (cache->ro) {
space_info->bytes_readonly += len;
readonly = true;
}
spin_unlock(&cache->lock);
if (!readonly && return_free_space &&
global_rsv->space_info == space_info) {
u64 to_add = len;
spin_lock(&global_rsv->lock);
if (!global_rsv->full) {
to_add = min(len, global_rsv->size -
global_rsv->reserved);
global_rsv->reserved += to_add;
btrfs_space_info_update_bytes_may_use(fs_info,
space_info, to_add);
if (global_rsv->reserved >= global_rsv->size)
global_rsv->full = 1;
trace_btrfs_space_reservation(fs_info,
"space_info",
space_info->flags,
to_add, 1);
len -= to_add;
}
spin_unlock(&global_rsv->lock);
/* Add to any tickets we may have */
if (len)
btrfs_space_info_add_new_bytes(fs_info,
space_info, len);
}
spin_unlock(&space_info->lock);
}
if (cache)
btrfs_put_block_group(cache);
return 0;
}
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *block_group, *tmp;
struct list_head *deleted_bgs;
struct extent_io_tree *unpin;
u64 start;
u64 end;
int ret;
if (fs_info->pinned_extents == &fs_info->freed_extents[0])
unpin = &fs_info->freed_extents[1];
else
unpin = &fs_info->freed_extents[0];
while (!trans->aborted) {
struct extent_state *cached_state = NULL;
mutex_lock(&fs_info->unused_bg_unpin_mutex);
ret = find_first_extent_bit(unpin, 0, &start, &end,
EXTENT_DIRTY, &cached_state);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
break;
}
if (btrfs_test_opt(fs_info, DISCARD))
ret = btrfs_discard_extent(fs_info, start,
end + 1 - start, NULL);
clear_extent_dirty(unpin, start, end, &cached_state);
unpin_extent_range(fs_info, start, end, true);
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
free_extent_state(cached_state);
cond_resched();
}
/*
* Transaction is finished. We don't need the lock anymore. We
* do need to clean up the block groups in case of a transaction
* abort.
*/
deleted_bgs = &trans->transaction->deleted_bgs;
list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
u64 trimmed = 0;
ret = -EROFS;
if (!trans->aborted)
ret = btrfs_discard_extent(fs_info,
block_group->key.objectid,
block_group->key.offset,
&trimmed);
list_del_init(&block_group->bg_list);
btrfs_put_block_group_trimming(block_group);
btrfs_put_block_group(block_group);
if (ret) {
const char *errstr = btrfs_decode_error(ret);
btrfs_warn(fs_info,
"discard failed while removing blockgroup: errno=%d %s",
ret, errstr);
}
}
return 0;
}
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node, u64 parent,
u64 root_objectid, u64 owner_objectid,
u64 owner_offset, int refs_to_drop,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_root *extent_root = info->extent_root;
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
int ret;
int is_data;
int extent_slot = 0;
int found_extent = 0;
int num_to_del = 1;
u32 item_size;
u64 refs;
u64 bytenr = node->bytenr;
u64 num_bytes = node->num_bytes;
int last_ref = 0;
bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
path->leave_spinning = 1;
is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
BUG_ON(!is_data && refs_to_drop != 1);
if (is_data)
skinny_metadata = false;
ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
parent, root_objectid, owner_objectid,
owner_offset);
if (ret == 0) {
extent_slot = path->slots[0];
while (extent_slot >= 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key,
extent_slot);
if (key.objectid != bytenr)
break;
if (key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes) {
found_extent = 1;
break;
}
if (key.type == BTRFS_METADATA_ITEM_KEY &&
key.offset == owner_objectid) {
found_extent = 1;
break;
}
if (path->slots[0] - extent_slot > 5)
break;
extent_slot--;
}
if (!found_extent) {
BUG_ON(iref);
ret = remove_extent_backref(trans, path, NULL,
refs_to_drop,
is_data, &last_ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
path->leave_spinning = 1;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
if (!is_data && skinny_metadata) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = owner_objectid;
}
ret = btrfs_search_slot(trans, extent_root,
&key, path, -1, 1);
if (ret > 0 && skinny_metadata && path->slots[0]) {
/*
* Couldn't find our skinny metadata item,
* see if we have ye olde extent item.
*/
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes)
ret = 0;
}
if (ret > 0 && skinny_metadata) {
skinny_metadata = false;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
btrfs_release_path(path);
ret = btrfs_search_slot(trans, extent_root,
&key, path, -1, 1);
}
if (ret) {
btrfs_err(info,
"umm, got %d back from search, was looking for %llu",
ret, bytenr);
if (ret > 0)
btrfs_print_leaf(path->nodes[0]);
}
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
extent_slot = path->slots[0];
}
} else if (WARN_ON(ret == -ENOENT)) {
btrfs_print_leaf(path->nodes[0]);
btrfs_err(info,
"unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
bytenr, parent, root_objectid, owner_objectid,
owner_offset);
btrfs_abort_transaction(trans, ret);
goto out;
} else {
btrfs_abort_transaction(trans, ret);
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, extent_slot);
if (unlikely(item_size < sizeof(*ei))) {
ret = -EINVAL;
btrfs_print_v0_err(info);
btrfs_abort_transaction(trans, ret);
goto out;
}
ei = btrfs_item_ptr(leaf, extent_slot,
struct btrfs_extent_item);
if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
key.type == BTRFS_EXTENT_ITEM_KEY) {
struct btrfs_tree_block_info *bi;
BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
bi = (struct btrfs_tree_block_info *)(ei + 1);
WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
}
refs = btrfs_extent_refs(leaf, ei);
if (refs < refs_to_drop) {
btrfs_err(info,
"trying to drop %d refs but we only have %Lu for bytenr %Lu",
refs_to_drop, refs, bytenr);
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
refs -= refs_to_drop;
if (refs > 0) {
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
/*
* In the case of inline back ref, reference count will
* be updated by remove_extent_backref
*/
if (iref) {
BUG_ON(!found_extent);
} else {
btrfs_set_extent_refs(leaf, ei, refs);
btrfs_mark_buffer_dirty(leaf);
}
if (found_extent) {
ret = remove_extent_backref(trans, path, iref,
refs_to_drop, is_data,
&last_ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
} else {
if (found_extent) {
BUG_ON(is_data && refs_to_drop !=
extent_data_ref_count(path, iref));
if (iref) {
BUG_ON(path->slots[0] != extent_slot);
} else {
BUG_ON(path->slots[0] != extent_slot + 1);
path->slots[0] = extent_slot;
num_to_del = 2;
}
}
last_ref = 1;
ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
num_to_del);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
if (is_data) {
ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
ret = add_to_free_space_tree(trans, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
ret = update_block_group(trans, bytenr, num_bytes, 0);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
btrfs_release_path(path);
out:
btrfs_free_path(path);
return ret;
}
/*
* when we free an block, it is possible (and likely) that we free the last
* delayed ref for that extent as well. This searches the delayed ref tree for
* a given extent, and if there are no other delayed refs to be processed, it
* removes it from the tree.
*/
static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
u64 bytenr)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
int ret = 0;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head)
goto out_delayed_unlock;
spin_lock(&head->lock);
if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
goto out;
if (cleanup_extent_op(head) != NULL)
goto out;
/*
* waiting for the lock here would deadlock. If someone else has it
* locked they are already in the process of dropping it anyway
*/
if (!mutex_trylock(&head->mutex))
goto out;
btrfs_delete_ref_head(delayed_refs, head);
head->processing = 0;
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
BUG_ON(head->extent_op);
if (head->must_insert_reserved)
ret = 1;
btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
return ret;
out:
spin_unlock(&head->lock);
out_delayed_unlock:
spin_unlock(&delayed_refs->lock);
return 0;
}
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
u64 parent, int last_ref)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_ref generic_ref = { 0 };
int pin = 1;
int ret;
btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
buf->start, buf->len, parent);
btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
root->root_key.objectid);
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
int old_ref_mod, new_ref_mod;
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL,
&old_ref_mod, &new_ref_mod);
BUG_ON(ret); /* -ENOMEM */
pin = old_ref_mod >= 0 && new_ref_mod < 0;
}
if (last_ref && btrfs_header_generation(buf) == trans->transid) {
struct btrfs_block_group_cache *cache;
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
ret = check_ref_cleanup(trans, buf->start);
if (!ret)
goto out;
}
pin = 0;
cache = btrfs_lookup_block_group(fs_info, buf->start);
if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
pin_down_extent(cache, buf->start, buf->len, 1);
btrfs_put_block_group(cache);
goto out;
}
WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
btrfs_add_free_space(cache, buf->start, buf->len);
btrfs_free_reserved_bytes(cache, buf->len, 0);
btrfs_put_block_group(cache);
trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
}
out:
if (pin)
add_pinned_bytes(fs_info, &generic_ref);
if (last_ref) {
/*
* Deleting the buffer, clear the corrupt flag since it doesn't
* matter anymore.
*/
clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
}
}
/* Can return -ENOMEM */
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int old_ref_mod, new_ref_mod;
int ret;
if (btrfs_is_testing(fs_info))
return 0;
/*
* tree log blocks never actually go into the extent allocation
* tree, just update pinning info and exit early.
*/
if ((ref->type == BTRFS_REF_METADATA &&
ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
(ref->type == BTRFS_REF_DATA &&
ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
/* unlocks the pinned mutex */
btrfs_pin_extent(fs_info, ref->bytenr, ref->len, 1);
old_ref_mod = new_ref_mod = 0;
ret = 0;
} else if (ref->type == BTRFS_REF_METADATA) {
ret = btrfs_add_delayed_tree_ref(trans, ref, NULL,
&old_ref_mod, &new_ref_mod);
} else {
ret = btrfs_add_delayed_data_ref(trans, ref, 0,
&old_ref_mod, &new_ref_mod);
}
if (!((ref->type == BTRFS_REF_METADATA &&
ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
(ref->type == BTRFS_REF_DATA &&
ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
btrfs_ref_tree_mod(fs_info, ref);
if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
add_pinned_bytes(fs_info, ref);
return ret;
}
/*
* when we wait for progress in the block group caching, its because
* our allocation attempt failed at least once. So, we must sleep
* and let some progress happen before we try again.
*
* This function will sleep at least once waiting for new free space to
* show up, and then it will check the block group free space numbers
* for our min num_bytes. Another option is to have it go ahead
* and look in the rbtree for a free extent of a given size, but this
* is a good start.
*
* Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
* any of the information in this block group.
*/
void btrfs_wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
u64 num_bytes)
{
struct btrfs_caching_control *caching_ctl;
caching_ctl = btrfs_get_caching_control(cache);
if (!caching_ctl)
return;
wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache) ||
(cache->free_space_ctl->free_space >= num_bytes));
btrfs_put_caching_control(caching_ctl);
}
int btrfs_wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
{
struct btrfs_caching_control *caching_ctl;
int ret = 0;
caching_ctl = btrfs_get_caching_control(cache);
if (!caching_ctl)
return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache));
if (cache->cached == BTRFS_CACHE_ERROR)
ret = -EIO;
btrfs_put_caching_control(caching_ctl);
return ret;
}
enum btrfs_loop_type {
LOOP_CACHING_NOWAIT,
LOOP_CACHING_WAIT,
LOOP_ALLOC_CHUNK,
LOOP_NO_EMPTY_SIZE,
};
static inline void
btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
int delalloc)
{
if (delalloc)
down_read(&cache->data_rwsem);
}
static inline void
btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
int delalloc)
{
btrfs_get_block_group(cache);
if (delalloc)
down_read(&cache->data_rwsem);
}
static struct btrfs_block_group_cache *
btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
struct btrfs_free_cluster *cluster,
int delalloc)
{
struct btrfs_block_group_cache *used_bg = NULL;
spin_lock(&cluster->refill_lock);
while (1) {
used_bg = cluster->block_group;
if (!used_bg)
return NULL;
if (used_bg == block_group)
return used_bg;
btrfs_get_block_group(used_bg);
if (!delalloc)
return used_bg;
if (down_read_trylock(&used_bg->data_rwsem))
return used_bg;
spin_unlock(&cluster->refill_lock);
/* We should only have one-level nested. */
down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
spin_lock(&cluster->refill_lock);
if (used_bg == cluster->block_group)
return used_bg;
up_read(&used_bg->data_rwsem);
btrfs_put_block_group(used_bg);
}
}
static inline void
btrfs_release_block_group(struct btrfs_block_group_cache *cache,
int delalloc)
{
if (delalloc)
up_read(&cache->data_rwsem);
btrfs_put_block_group(cache);
}
/*
* Structure used internally for find_free_extent() function. Wraps needed
* parameters.
*/
struct find_free_extent_ctl {
/* Basic allocation info */
u64 ram_bytes;
u64 num_bytes;
u64 empty_size;
u64 flags;
int delalloc;
/* Where to start the search inside the bg */
u64 search_start;
/* For clustered allocation */
u64 empty_cluster;
bool have_caching_bg;
bool orig_have_caching_bg;
/* RAID index, converted from flags */
int index;
/*
* Current loop number, check find_free_extent_update_loop() for details
*/
int loop;
/*
* Whether we're refilling a cluster, if true we need to re-search
* current block group but don't try to refill the cluster again.
*/
bool retry_clustered;
/*
* Whether we're updating free space cache, if true we need to re-search
* current block group but don't try updating free space cache again.
*/
bool retry_unclustered;
/* If current block group is cached */
int cached;
/* Max contiguous hole found */
u64 max_extent_size;
/* Total free space from free space cache, not always contiguous */
u64 total_free_space;
/* Found result */
u64 found_offset;
};
/*
* Helper function for find_free_extent().
*
* Return -ENOENT to inform caller that we need fallback to unclustered mode.
* Return -EAGAIN to inform caller that we need to re-search this block group
* Return >0 to inform caller that we find nothing
* Return 0 means we have found a location and set ffe_ctl->found_offset.
*/
static int find_free_extent_clustered(struct btrfs_block_group_cache *bg,
struct btrfs_free_cluster *last_ptr,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group_cache **cluster_bg_ret)
{
struct btrfs_block_group_cache *cluster_bg;
u64 aligned_cluster;
u64 offset;
int ret;
cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
if (!cluster_bg)
goto refill_cluster;
if (cluster_bg != bg && (cluster_bg->ro ||
!block_group_bits(cluster_bg, ffe_ctl->flags)))
goto release_cluster;
offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
ffe_ctl->num_bytes, cluster_bg->key.objectid,
&ffe_ctl->max_extent_size);
if (offset) {
/* We have a block, we're done */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(cluster_bg,
ffe_ctl->search_start, ffe_ctl->num_bytes);
*cluster_bg_ret = cluster_bg;
ffe_ctl->found_offset = offset;
return 0;
}
WARN_ON(last_ptr->block_group != cluster_bg);
release_cluster:
/*
* If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
* lets just skip it and let the allocator find whatever block it can
* find. If we reach this point, we will have tried the cluster
* allocator plenty of times and not have found anything, so we are
* likely way too fragmented for the clustering stuff to find anything.
*
* However, if the cluster is taken from the current block group,
* release the cluster first, so that we stand a better chance of
* succeeding in the unclustered allocation.
*/
if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
spin_unlock(&last_ptr->refill_lock);
btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
return -ENOENT;
}
/* This cluster didn't work out, free it and start over */
btrfs_return_cluster_to_free_space(NULL, last_ptr);
if (cluster_bg != bg)
btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
refill_cluster:
if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
spin_unlock(&last_ptr->refill_lock);
return -ENOENT;
}
aligned_cluster = max_t(u64,
ffe_ctl->empty_cluster + ffe_ctl->empty_size,
bg->full_stripe_len);
ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
ffe_ctl->num_bytes, aligned_cluster);
if (ret == 0) {
/* Now pull our allocation out of this cluster */
offset = btrfs_alloc_from_cluster(bg, last_ptr,
ffe_ctl->num_bytes, ffe_ctl->search_start,
&ffe_ctl->max_extent_size);
if (offset) {
/* We found one, proceed */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(bg,
ffe_ctl->search_start,
ffe_ctl->num_bytes);
ffe_ctl->found_offset = offset;
return 0;
}
} else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
!ffe_ctl->retry_clustered) {
spin_unlock(&last_ptr->refill_lock);
ffe_ctl->retry_clustered = true;
btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
ffe_ctl->empty_cluster + ffe_ctl->empty_size);
return -EAGAIN;
}
/*
* At this point we either didn't find a cluster or we weren't able to
* allocate a block from our cluster. Free the cluster we've been
* trying to use, and go to the next block group.
*/
btrfs_return_cluster_to_free_space(NULL, last_ptr);
spin_unlock(&last_ptr->refill_lock);
return 1;
}
/*
* Return >0 to inform caller that we find nothing
* Return 0 when we found an free extent and set ffe_ctrl->found_offset
* Return -EAGAIN to inform caller that we need to re-search this block group
*/
static int find_free_extent_unclustered(struct btrfs_block_group_cache *bg,
struct btrfs_free_cluster *last_ptr,
struct find_free_extent_ctl *ffe_ctl)
{
u64 offset;
/*
* We are doing an unclustered allocation, set the fragmented flag so
* we don't bother trying to setup a cluster again until we get more
* space.
*/
if (unlikely(last_ptr)) {
spin_lock(&last_ptr->lock);
last_ptr->fragmented = 1;
spin_unlock(&last_ptr->lock);
}
if (ffe_ctl->cached) {
struct btrfs_free_space_ctl *free_space_ctl;
free_space_ctl = bg->free_space_ctl;
spin_lock(&free_space_ctl->tree_lock);
if (free_space_ctl->free_space <
ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
ffe_ctl->empty_size) {
ffe_ctl->total_free_space = max_t(u64,
ffe_ctl->total_free_space,
free_space_ctl->free_space);
spin_unlock(&free_space_ctl->tree_lock);
return 1;
}
spin_unlock(&free_space_ctl->tree_lock);
}
offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
ffe_ctl->num_bytes, ffe_ctl->empty_size,
&ffe_ctl->max_extent_size);
/*
* If we didn't find a chunk, and we haven't failed on this block group
* before, and this block group is in the middle of caching and we are
* ok with waiting, then go ahead and wait for progress to be made, and
* set @retry_unclustered to true.
*
* If @retry_unclustered is true then we've already waited on this
* block group once and should move on to the next block group.
*/
if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
ffe_ctl->empty_size);
ffe_ctl->retry_unclustered = true;
return -EAGAIN;
} else if (!offset) {
return 1;
}
ffe_ctl->found_offset = offset;
return 0;
}
/*
* Return >0 means caller needs to re-search for free extent
* Return 0 means we have the needed free extent.
* Return <0 means we failed to locate any free extent.
*/
static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
struct btrfs_free_cluster *last_ptr,
struct btrfs_key *ins,
struct find_free_extent_ctl *ffe_ctl,
int full_search, bool use_cluster)
{
struct btrfs_root *root = fs_info->extent_root;
int ret;
if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
ffe_ctl->orig_have_caching_bg = true;
if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT &&
ffe_ctl->have_caching_bg)
return 1;
if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES)
return 1;
if (ins->objectid) {
if (!use_cluster && last_ptr) {
spin_lock(&last_ptr->lock);
last_ptr->window_start = ins->objectid;
spin_unlock(&last_ptr->lock);
}
return 0;
}
/*
* LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
* caching kthreads as we move along
* LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
* LOOP_ALLOC_CHUNK, force a chunk allocation and try again
* LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
* again
*/
if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
ffe_ctl->index = 0;
if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
/*
* We want to skip the LOOP_CACHING_WAIT step if we
* don't have any uncached bgs and we've already done a
* full search through.
*/
if (ffe_ctl->orig_have_caching_bg || !full_search)
ffe_ctl->loop = LOOP_CACHING_WAIT;
else
ffe_ctl->loop = LOOP_ALLOC_CHUNK;
} else {
ffe_ctl->loop++;
}
if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
struct btrfs_trans_handle *trans;
int exist = 0;
trans = current->journal_info;
if (trans)
exist = 1;
else
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
return ret;
}
ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
CHUNK_ALLOC_FORCE);
/*
* If we can't allocate a new chunk we've already looped
* through at least once, move on to the NO_EMPTY_SIZE
* case.
*/
if (ret == -ENOSPC)
ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
/* Do not bail out on ENOSPC since we can do more. */
if (ret < 0 && ret != -ENOSPC)
btrfs_abort_transaction(trans, ret);
else
ret = 0;
if (!exist)
btrfs_end_transaction(trans);
if (ret)
return ret;
}
if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
/*
* Don't loop again if we already have no empty_size and
* no empty_cluster.
*/
if (ffe_ctl->empty_size == 0 &&
ffe_ctl->empty_cluster == 0)
return -ENOSPC;
ffe_ctl->empty_size = 0;
ffe_ctl->empty_cluster = 0;
}
return 1;
}
return -ENOSPC;
}
/*
* walks the btree of allocated extents and find a hole of a given size.
* The key ins is changed to record the hole:
* ins->objectid == start position
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == the size of the hole.
* Any available blocks before search_start are skipped.
*
* If there is no suitable free space, we will record the max size of
* the free space extent currently.
*
* The overall logic and call chain:
*
* find_free_extent()
* |- Iterate through all block groups
* | |- Get a valid block group
* | |- Try to do clustered allocation in that block group
* | |- Try to do unclustered allocation in that block group
* | |- Check if the result is valid
* | | |- If valid, then exit
* | |- Jump to next block group
* |
* |- Push harder to find free extents
* |- If not found, re-iterate all block groups
*/
static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
u64 ram_bytes, u64 num_bytes, u64 empty_size,
u64 hint_byte, struct btrfs_key *ins,
u64 flags, int delalloc)
{
int ret = 0;
struct btrfs_free_cluster *last_ptr = NULL;
struct btrfs_block_group_cache *block_group = NULL;
struct find_free_extent_ctl ffe_ctl = {0};
struct btrfs_space_info *space_info;
bool use_cluster = true;
bool full_search = false;
WARN_ON(num_bytes < fs_info->sectorsize);
ffe_ctl.ram_bytes = ram_bytes;
ffe_ctl.num_bytes = num_bytes;
ffe_ctl.empty_size = empty_size;
ffe_ctl.flags = flags;
ffe_ctl.search_start = 0;
ffe_ctl.retry_clustered = false;
ffe_ctl.retry_unclustered = false;
ffe_ctl.delalloc = delalloc;
ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
ffe_ctl.have_caching_bg = false;
ffe_ctl.orig_have_caching_bg = false;
ffe_ctl.found_offset = 0;
ins->type = BTRFS_EXTENT_ITEM_KEY;
ins->objectid = 0;
ins->offset = 0;
trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
space_info = btrfs_find_space_info(fs_info, flags);
if (!space_info) {
btrfs_err(fs_info, "No space info for %llu", flags);
return -ENOSPC;
}
/*
* If our free space is heavily fragmented we may not be able to make
* big contiguous allocations, so instead of doing the expensive search
* for free space, simply return ENOSPC with our max_extent_size so we
* can go ahead and search for a more manageable chunk.
*
* If our max_extent_size is large enough for our allocation simply
* disable clustering since we will likely not be able to find enough
* space to create a cluster and induce latency trying.
*/
if (unlikely(space_info->max_extent_size)) {
spin_lock(&space_info->lock);
if (space_info->max_extent_size &&
num_bytes > space_info->max_extent_size) {
ins->offset = space_info->max_extent_size;
spin_unlock(&space_info->lock);
return -ENOSPC;
} else if (space_info->max_extent_size) {
use_cluster = false;
}
spin_unlock(&space_info->lock);
}
last_ptr = fetch_cluster_info(fs_info, space_info,
&ffe_ctl.empty_cluster);
if (last_ptr) {
spin_lock(&last_ptr->lock);
if (last_ptr->block_group)
hint_byte = last_ptr->window_start;
if (last_ptr->fragmented) {
/*
* We still set window_start so we can keep track of the
* last place we found an allocation to try and save
* some time.
*/
hint_byte = last_ptr->window_start;
use_cluster = false;
}
spin_unlock(&last_ptr->lock);
}
ffe_ctl.search_start = max(ffe_ctl.search_start,
first_logical_byte(fs_info, 0));
ffe_ctl.search_start = max(ffe_ctl.search_start, hint_byte);
if (ffe_ctl.search_start == hint_byte) {
block_group = btrfs_lookup_block_group(fs_info,
ffe_ctl.search_start);
/*
* we don't want to use the block group if it doesn't match our
* allocation bits, or if its not cached.
*
* However if we are re-searching with an ideal block group
* picked out then we don't care that the block group is cached.
*/
if (block_group && block_group_bits(block_group, flags) &&
block_group->cached != BTRFS_CACHE_NO) {
down_read(&space_info->groups_sem);
if (list_empty(&block_group->list) ||
block_group->ro) {
/*
* someone is removing this block group,
* we can't jump into the have_block_group
* target because our list pointers are not
* valid
*/
btrfs_put_block_group(block_group);
up_read(&space_info->groups_sem);
} else {
ffe_ctl.index = btrfs_bg_flags_to_raid_index(
block_group->flags);
btrfs_lock_block_group(block_group, delalloc);
goto have_block_group;
}
} else if (block_group) {
btrfs_put_block_group(block_group);
}
}
search:
ffe_ctl.have_caching_bg = false;
if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
ffe_ctl.index == 0)
full_search = true;
down_read(&space_info->groups_sem);
list_for_each_entry(block_group,
&space_info->block_groups[ffe_ctl.index], list) {
/* If the block group is read-only, we can skip it entirely. */
if (unlikely(block_group->ro))
continue;
btrfs_grab_block_group(block_group, delalloc);
ffe_ctl.search_start = block_group->key.objectid;
/*
* this can happen if we end up cycling through all the
* raid types, but we want to make sure we only allocate
* for the proper type.
*/
if (!block_group_bits(block_group, flags)) {
u64 extra = BTRFS_BLOCK_GROUP_DUP |
BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_RAID10;
/*
* if they asked for extra copies and this block group
* doesn't provide them, bail. This does allow us to
* fill raid0 from raid1.
*/
if ((flags & extra) && !(block_group->flags & extra))
goto loop;
/*
* This block group has different flags than we want.
* It's possible that we have MIXED_GROUP flag but no
* block group is mixed. Just skip such block group.
*/
btrfs_release_block_group(block_group, delalloc);
continue;
}
have_block_group:
ffe_ctl.cached = btrfs_block_group_cache_done(block_group);
if (unlikely(!ffe_ctl.cached)) {
ffe_ctl.have_caching_bg = true;
ret = btrfs_cache_block_group(block_group, 0);
BUG_ON(ret < 0);
ret = 0;
}
if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
goto loop;
/*
* Ok we want to try and use the cluster allocator, so
* lets look there
*/
if (last_ptr && use_cluster) {
struct btrfs_block_group_cache *cluster_bg = NULL;
ret = find_free_extent_clustered(block_group, last_ptr,
&ffe_ctl, &cluster_bg);
if (ret == 0) {
if (cluster_bg && cluster_bg != block_group) {
btrfs_release_block_group(block_group,
delalloc);
block_group = cluster_bg;
}
goto checks;
} else if (ret == -EAGAIN) {
goto have_block_group;
} else if (ret > 0) {
goto loop;
}
/* ret == -ENOENT case falls through */
}
ret = find_free_extent_unclustered(block_group, last_ptr,
&ffe_ctl);
if (ret == -EAGAIN)
goto have_block_group;
else if (ret > 0)
goto loop;
/* ret == 0 case falls through */
checks:
ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
fs_info->stripesize);
/* move on to the next group */
if (ffe_ctl.search_start + num_bytes >
block_group->key.objectid + block_group->key.offset) {
btrfs_add_free_space(block_group, ffe_ctl.found_offset,
num_bytes);
goto loop;
}
if (ffe_ctl.found_offset < ffe_ctl.search_start)
btrfs_add_free_space(block_group, ffe_ctl.found_offset,
ffe_ctl.search_start - ffe_ctl.found_offset);
ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
num_bytes, delalloc);
if (ret == -EAGAIN) {
btrfs_add_free_space(block_group, ffe_ctl.found_offset,
num_bytes);
goto loop;
}
btrfs_inc_block_group_reservations(block_group);
/* we are all good, lets return */
ins->objectid = ffe_ctl.search_start;
ins->offset = num_bytes;
trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
num_bytes);
btrfs_release_block_group(block_group, delalloc);
break;
loop:
ffe_ctl.retry_clustered = false;
ffe_ctl.retry_unclustered = false;
BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
ffe_ctl.index);
btrfs_release_block_group(block_group, delalloc);
cond_resched();
}
up_read(&space_info->groups_sem);
ret = find_free_extent_update_loop(fs_info, last_ptr, ins, &ffe_ctl,
full_search, use_cluster);
if (ret > 0)
goto search;
if (ret == -ENOSPC) {
/*
* Use ffe_ctl->total_free_space as fallback if we can't find
* any contiguous hole.
*/
if (!ffe_ctl.max_extent_size)
ffe_ctl.max_extent_size = ffe_ctl.total_free_space;
spin_lock(&space_info->lock);
space_info->max_extent_size = ffe_ctl.max_extent_size;
spin_unlock(&space_info->lock);
ins->offset = ffe_ctl.max_extent_size;
}
return ret;
}
/*
* btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
* hole that is at least as big as @num_bytes.
*
* @root - The root that will contain this extent
*
* @ram_bytes - The amount of space in ram that @num_bytes take. This
* is used for accounting purposes. This value differs
* from @num_bytes only in the case of compressed extents.
*
* @num_bytes - Number of bytes to allocate on-disk.
*
* @min_alloc_size - Indicates the minimum amount of space that the
* allocator should try to satisfy. In some cases
* @num_bytes may be larger than what is required and if
* the filesystem is fragmented then allocation fails.
* However, the presence of @min_alloc_size gives a
* chance to try and satisfy the smaller allocation.
*
* @empty_size - A hint that you plan on doing more COW. This is the
* size in bytes the allocator should try to find free
* next to the block it returns. This is just a hint and
* may be ignored by the allocator.
*
* @hint_byte - Hint to the allocator to start searching above the byte
* address passed. It might be ignored.
*
* @ins - This key is modified to record the found hole. It will
* have the following values:
* ins->objectid == start position
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == the size of the hole.
*
* @is_data - Boolean flag indicating whether an extent is
* allocated for data (true) or metadata (false)
*
* @delalloc - Boolean flag indicating whether this allocation is for
* delalloc or not. If 'true' data_rwsem of block groups
* is going to be acquired.
*
*
* Returns 0 when an allocation succeeded or < 0 when an error occurred. In
* case -ENOSPC is returned then @ins->offset will contain the size of the
* largest available hole the allocator managed to find.
*/
int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
u64 num_bytes, u64 min_alloc_size,
u64 empty_size, u64 hint_byte,
struct btrfs_key *ins, int is_data, int delalloc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
bool final_tried = num_bytes == min_alloc_size;
u64 flags;
int ret;
flags = get_alloc_profile_by_root(root, is_data);
again:
WARN_ON(num_bytes < fs_info->sectorsize);
ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
hint_byte, ins, flags, delalloc);
if (!ret && !is_data) {
btrfs_dec_block_group_reservations(fs_info, ins->objectid);
} else if (ret == -ENOSPC) {
if (!final_tried && ins->offset) {
num_bytes = min(num_bytes >> 1, ins->offset);
num_bytes = round_down(num_bytes,
fs_info->sectorsize);
num_bytes = max(num_bytes, min_alloc_size);
ram_bytes = num_bytes;
if (num_bytes == min_alloc_size)
final_tried = true;
goto again;
} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
struct btrfs_space_info *sinfo;
sinfo = btrfs_find_space_info(fs_info, flags);
btrfs_err(fs_info,
"allocation failed flags %llu, wanted %llu",
flags, num_bytes);
if (sinfo)
btrfs_dump_space_info(fs_info, sinfo,
num_bytes, 1);
}
}
return ret;
}
static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len,
int pin, int delalloc)
{
struct btrfs_block_group_cache *cache;
int ret = 0;
cache = btrfs_lookup_block_group(fs_info, start);
if (!cache) {
btrfs_err(fs_info, "Unable to find block group for %llu",
start);
return -ENOSPC;
}
if (pin)
pin_down_extent(cache, start, len, 1);
else {
if (btrfs_test_opt(fs_info, DISCARD))
ret = btrfs_discard_extent(fs_info, start, len, NULL);
btrfs_add_free_space(cache, start, len);
btrfs_free_reserved_bytes(cache, len, delalloc);
trace_btrfs_reserved_extent_free(fs_info, start, len);
}
btrfs_put_block_group(cache);
return ret;
}
int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len, int delalloc)
{
return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
}
int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len)
{
return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
}
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
u64 flags, u64 owner, u64 offset,
struct btrfs_key *ins, int ref_mod)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_extent_item *extent_item;
struct btrfs_extent_inline_ref *iref;
struct btrfs_path *path;
struct extent_buffer *leaf;
int type;
u32 size;
if (parent > 0)
type = BTRFS_SHARED_DATA_REF_KEY;
else
type = BTRFS_EXTENT_DATA_REF_KEY;
size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
ins, size);
if (ret) {
btrfs_free_path(path);
return ret;
}
leaf = path->nodes[0];
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, extent_item, ref_mod);
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
btrfs_set_extent_flags(leaf, extent_item,
flags | BTRFS_EXTENT_FLAG_DATA);
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
btrfs_set_extent_inline_ref_type(leaf, iref, type);
if (parent > 0) {
struct btrfs_shared_data_ref *ref;
ref = (struct btrfs_shared_data_ref *)(iref + 1);
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
} else {
struct btrfs_extent_data_ref *ref;
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
}
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_free_path(path);
ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
if (ret)
return ret;
ret = update_block_group(trans, ins->objectid, ins->offset, 1);
if (ret) { /* -ENOENT, logic error */
btrfs_err(fs_info, "update block group failed for %llu %llu",
ins->objectid, ins->offset);
BUG();
}
trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
return ret;
}
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_extent_item *extent_item;
struct btrfs_key extent_key;
struct btrfs_tree_block_info *block_info;
struct btrfs_extent_inline_ref *iref;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_delayed_tree_ref *ref;
u32 size = sizeof(*extent_item) + sizeof(*iref);
u64 num_bytes;
u64 flags = extent_op->flags_to_set;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
ref = btrfs_delayed_node_to_tree_ref(node);
extent_key.objectid = node->bytenr;
if (skinny_metadata) {
extent_key.offset = ref->level;
extent_key.type = BTRFS_METADATA_ITEM_KEY;
num_bytes = fs_info->nodesize;
} else {
extent_key.offset = node->num_bytes;
extent_key.type = BTRFS_EXTENT_ITEM_KEY;
size += sizeof(*block_info);
num_bytes = node->num_bytes;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
&extent_key, size);
if (ret) {
btrfs_free_path(path);
return ret;
}
leaf = path->nodes[0];
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, extent_item, 1);
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
btrfs_set_extent_flags(leaf, extent_item,
flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
if (skinny_metadata) {
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
} else {
block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
btrfs_set_tree_block_level(leaf, block_info, ref->level);
iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
}
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
btrfs_set_extent_inline_ref_type(leaf, iref,
BTRFS_SHARED_BLOCK_REF_KEY);
btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
} else {
btrfs_set_extent_inline_ref_type(leaf, iref,
BTRFS_TREE_BLOCK_REF_KEY);
btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
}
btrfs_mark_buffer_dirty(leaf);
btrfs_free_path(path);
ret = remove_from_free_space_tree(trans, extent_key.objectid,
num_bytes);
if (ret)
return ret;
ret = update_block_group(trans, extent_key.objectid,
fs_info->nodesize, 1);
if (ret) { /* -ENOENT, logic error */
btrfs_err(fs_info, "update block group failed for %llu %llu",
extent_key.objectid, extent_key.offset);
BUG();
}
trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
fs_info->nodesize);
return ret;
}
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 owner,
u64 offset, u64 ram_bytes,
struct btrfs_key *ins)
{
struct btrfs_ref generic_ref = { 0 };
int ret;
BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
ins->objectid, ins->offset, 0);
btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner, offset);
btrfs_ref_tree_mod(root->fs_info, &generic_ref);
ret = btrfs_add_delayed_data_ref(trans, &generic_ref,
ram_bytes, NULL, NULL);
return ret;
}
/*
* this is used by the tree logging recovery code. It records that
* an extent has been allocated and makes sure to clear the free
* space cache bits as well
*/
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
u64 root_objectid, u64 owner, u64 offset,
struct btrfs_key *ins)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
/*
* Mixed block groups will exclude before processing the log so we only
* need to do the exclude dance if this fs isn't mixed.
*/
if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
ret = __exclude_logged_extent(fs_info, ins->objectid,
ins->offset);
if (ret)
return ret;
}
block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
if (!block_group)
return -EINVAL;
space_info = block_group->space_info;
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
space_info->bytes_reserved += ins->offset;
block_group->reserved += ins->offset;
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
offset, ins, 1);
btrfs_put_block_group(block_group);
return ret;
}
static struct extent_buffer *
btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 bytenr, int level, u64 owner)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *buf;
buf = btrfs_find_create_tree_block(fs_info, bytenr);
if (IS_ERR(buf))
return buf;
/*
* Extra safety check in case the extent tree is corrupted and extent
* allocator chooses to use a tree block which is already used and
* locked.
*/
if (buf->lock_owner == current->pid) {
btrfs_err_rl(fs_info,
"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
buf->start, btrfs_header_owner(buf), current->pid);
free_extent_buffer(buf);
return ERR_PTR(-EUCLEAN);
}
btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
btrfs_tree_lock(buf);
btrfs_clean_tree_block(buf);
clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
btrfs_set_lock_blocking_write(buf);
set_extent_buffer_uptodate(buf);
memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
btrfs_set_header_level(buf, level);
btrfs_set_header_bytenr(buf, buf->start);
btrfs_set_header_generation(buf, trans->transid);
btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(buf, owner);
write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
buf->log_index = root->log_transid % 2;
/*
* we allow two log transactions at a time, use different
* EXTENT bit to differentiate dirty pages.
*/
if (buf->log_index == 0)
set_extent_dirty(&root->dirty_log_pages, buf->start,
buf->start + buf->len - 1, GFP_NOFS);
else
set_extent_new(&root->dirty_log_pages, buf->start,
buf->start + buf->len - 1);
} else {
buf->log_index = -1;
set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
buf->start + buf->len - 1, GFP_NOFS);
}
trans->dirty = true;
/* this returns a buffer locked for blocking */
return buf;
}
/*
* finds a free extent and does all the dirty work required for allocation
* returns the tree buffer or an ERR_PTR on error.
*/
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 parent, u64 root_objectid,
const struct btrfs_disk_key *key,
int level, u64 hint,
u64 empty_size)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key ins;
struct btrfs_block_rsv *block_rsv;
struct extent_buffer *buf;
struct btrfs_delayed_extent_op *extent_op;
struct btrfs_ref generic_ref = { 0 };
u64 flags = 0;
int ret;
u32 blocksize = fs_info->nodesize;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (btrfs_is_testing(fs_info)) {
buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
level, root_objectid);
if (!IS_ERR(buf))
root->alloc_bytenr += blocksize;
return buf;
}
#endif
block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
if (IS_ERR(block_rsv))
return ERR_CAST(block_rsv);
ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
empty_size, hint, &ins, 0, 0);
if (ret)
goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
root_objectid);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_free_reserved;
}
if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
if (parent == 0)
parent = ins.objectid;
flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
} else
BUG_ON(parent > 0);
if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
extent_op = btrfs_alloc_delayed_extent_op();
if (!extent_op) {
ret = -ENOMEM;
goto out_free_buf;
}
if (key)
memcpy(&extent_op->key, key, sizeof(extent_op->key));
else
memset(&extent_op->key, 0, sizeof(extent_op->key));
extent_op->flags_to_set = flags;
extent_op->update_key = skinny_metadata ? false : true;
extent_op->update_flags = true;
extent_op->is_data = false;
extent_op->level = level;
btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
ins.objectid, ins.offset, parent);
generic_ref.real_root = root->root_key.objectid;
btrfs_init_tree_ref(&generic_ref, level, root_objectid);
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref,
extent_op, NULL, NULL);
if (ret)
goto out_free_delayed;
}
return buf;
out_free_delayed:
btrfs_free_delayed_extent_op(extent_op);
out_free_buf:
free_extent_buffer(buf);
out_free_reserved:
btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
out_unuse:
btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
return ERR_PTR(ret);
}
struct walk_control {
u64 refs[BTRFS_MAX_LEVEL];
u64 flags[BTRFS_MAX_LEVEL];
struct btrfs_key update_progress;
struct btrfs_key drop_progress;
int drop_level;
int stage;
int level;
int shared_level;
int update_ref;
int keep_locks;
int reada_slot;
int reada_count;
int restarted;
};
#define DROP_REFERENCE 1
#define UPDATE_BACKREF 2
static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct walk_control *wc,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 generation;
u64 refs;
u64 flags;
u32 nritems;
struct btrfs_key key;
struct extent_buffer *eb;
int ret;
int slot;
int nread = 0;
if (path->slots[wc->level] < wc->reada_slot) {
wc->reada_count = wc->reada_count * 2 / 3;
wc->reada_count = max(wc->reada_count, 2);
} else {
wc->reada_count = wc->reada_count * 3 / 2;
wc->reada_count = min_t(int, wc->reada_count,
BTRFS_NODEPTRS_PER_BLOCK(fs_info));
}
eb = path->nodes[wc->level];
nritems = btrfs_header_nritems(eb);
for (slot = path->slots[wc->level]; slot < nritems; slot++) {
if (nread >= wc->reada_count)
break;
cond_resched();
bytenr = btrfs_node_blockptr(eb, slot);
generation = btrfs_node_ptr_generation(eb, slot);
if (slot == path->slots[wc->level])
goto reada;
if (wc->stage == UPDATE_BACKREF &&
generation <= root->root_key.offset)
continue;
/* We don't lock the tree block, it's OK to be racy here */
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
wc->level - 1, 1, &refs,
&flags);
/* We don't care about errors in readahead. */
if (ret < 0)
continue;
BUG_ON(refs == 0);
if (wc->stage == DROP_REFERENCE) {
if (refs == 1)
goto reada;
if (wc->level == 1 &&
(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
continue;
if (!wc->update_ref ||
generation <= root->root_key.offset)
continue;
btrfs_node_key_to_cpu(eb, &key, slot);
ret = btrfs_comp_cpu_keys(&key,
&wc->update_progress);
if (ret < 0)
continue;
} else {
if (wc->level == 1 &&
(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
continue;
}
reada:
readahead_tree_block(fs_info, bytenr);
nread++;
}
wc->reada_slot = slot;
}
/*
* helper to process tree block while walking down the tree.
*
* when wc->stage == UPDATE_BACKREF, this function updates
* back refs for pointers in the block.
*
* NOTE: return value 1 means we should stop walking down.
*/
static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int lookup_info)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int level = wc->level;
struct extent_buffer *eb = path->nodes[level];
u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
int ret;
if (wc->stage == UPDATE_BACKREF &&
btrfs_header_owner(eb) != root->root_key.objectid)
return 1;
/*
* when reference count of tree block is 1, it won't increase
* again. once full backref flag is set, we never clear it.
*/
if (lookup_info &&
((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
(wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
BUG_ON(!path->locks[level]);
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
&wc->refs[level],
&wc->flags[level]);
BUG_ON(ret == -ENOMEM);
if (ret)
return ret;
BUG_ON(wc->refs[level] == 0);
}
if (wc->stage == DROP_REFERENCE) {
if (wc->refs[level] > 1)
return 1;
if (path->locks[level] && !wc->keep_locks) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
}
return 0;
}
/* wc->stage == UPDATE_BACKREF */
if (!(wc->flags[level] & flag)) {
BUG_ON(!path->locks[level]);
ret = btrfs_inc_ref(trans, root, eb, 1);
BUG_ON(ret); /* -ENOMEM */
ret = btrfs_dec_ref(trans, root, eb, 0);
BUG_ON(ret); /* -ENOMEM */
ret = btrfs_set_disk_extent_flags(trans, eb->start,
eb->len, flag,
btrfs_header_level(eb), 0);
BUG_ON(ret); /* -ENOMEM */
wc->flags[level] |= flag;
}
/*
* the block is shared by multiple trees, so it's not good to
* keep the tree lock
*/
if (path->locks[level] && level > 0) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
}
return 0;
}
/*
* This is used to verify a ref exists for this root to deal with a bug where we
* would have a drop_progress key that hadn't been updated properly.
*/
static int check_ref_exists(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 bytenr, u64 parent,
int level)
{
struct btrfs_path *path;
struct btrfs_extent_inline_ref *iref;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = lookup_extent_backref(trans, path, &iref, bytenr,
root->fs_info->nodesize, parent,
root->root_key.objectid, level, 0);
btrfs_free_path(path);
if (ret == -ENOENT)
return 0;
if (ret < 0)
return ret;
return 1;
}
/*
* helper to process tree block pointer.
*
* when wc->stage == DROP_REFERENCE, this function checks
* reference count of the block pointed to. if the block
* is shared and we need update back refs for the subtree
* rooted at the block, this function changes wc->stage to
* UPDATE_BACKREF. if the block is shared and there is no
* need to update back, this function drops the reference
* to the block.
*
* NOTE: return value 1 means we should stop walking down.
*/
static noinline int do_walk_down(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int *lookup_info)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 generation;
u64 parent;
struct btrfs_key key;
struct btrfs_key first_key;
struct btrfs_ref ref = { 0 };
struct extent_buffer *next;
int level = wc->level;
int reada = 0;
int ret = 0;
bool need_account = false;
generation = btrfs_node_ptr_generation(path->nodes[level],
path->slots[level]);
/*
* if the lower level block was created before the snapshot
* was created, we know there is no need to update back refs
* for the subtree
*/
if (wc->stage == UPDATE_BACKREF &&
generation <= root->root_key.offset) {
*lookup_info = 1;
return 1;
}
bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
btrfs_node_key_to_cpu(path->nodes[level], &first_key,
path->slots[level]);
next = find_extent_buffer(fs_info, bytenr);
if (!next) {
next = btrfs_find_create_tree_block(fs_info, bytenr);
if (IS_ERR(next))
return PTR_ERR(next);
btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
level - 1);
reada = 1;
}
btrfs_tree_lock(next);
btrfs_set_lock_blocking_write(next);
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
&wc->refs[level - 1],
&wc->flags[level - 1]);
if (ret < 0)
goto out_unlock;
if (unlikely(wc->refs[level - 1] == 0)) {
btrfs_err(fs_info, "Missing references.");
ret = -EIO;
goto out_unlock;
}
*lookup_info = 0;
if (wc->stage == DROP_REFERENCE) {
if (wc->refs[level - 1] > 1) {
need_account = true;
if (level == 1 &&
(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
goto skip;
if (!wc->update_ref ||
generation <= root->root_key.offset)
goto skip;
btrfs_node_key_to_cpu(path->nodes[level], &key,
path->slots[level]);
ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
if (ret < 0)
goto skip;
wc->stage = UPDATE_BACKREF;
wc->shared_level = level - 1;
}
} else {
if (level == 1 &&
(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
goto skip;
}
if (!btrfs_buffer_uptodate(next, generation, 0)) {
btrfs_tree_unlock(next);
free_extent_buffer(next);
next = NULL;
*lookup_info = 1;
}
if (!next) {
if (reada && level == 1)
reada_walk_down(trans, root, wc, path);
next = read_tree_block(fs_info, bytenr, generation, level - 1,
&first_key);
if (IS_ERR(next)) {
return PTR_ERR(next);
} else if (!extent_buffer_uptodate(next)) {
free_extent_buffer(next);
return -EIO;
}
btrfs_tree_lock(next);
btrfs_set_lock_blocking_write(next);
}
level--;
ASSERT(level == btrfs_header_level(next));
if (level != btrfs_header_level(next)) {
btrfs_err(root->fs_info, "mismatched level");
ret = -EIO;
goto out_unlock;
}
path->nodes[level] = next;
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
wc->level = level;
if (wc->level == 1)
wc->reada_slot = 0;
return 0;
skip:
wc->refs[level - 1] = 0;
wc->flags[level - 1] = 0;
if (wc->stage == DROP_REFERENCE) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
parent = path->nodes[level]->start;
} else {
ASSERT(root->root_key.objectid ==
btrfs_header_owner(path->nodes[level]));
if (root->root_key.objectid !=
btrfs_header_owner(path->nodes[level])) {
btrfs_err(root->fs_info,
"mismatched block owner");
ret = -EIO;
goto out_unlock;
}
parent = 0;
}
/*
* If we had a drop_progress we need to verify the refs are set
* as expected. If we find our ref then we know that from here
* on out everything should be correct, and we can clear the
* ->restarted flag.
*/
if (wc->restarted) {
ret = check_ref_exists(trans, root, bytenr, parent,
level - 1);
if (ret < 0)
goto out_unlock;
if (ret == 0)
goto no_delete;
ret = 0;
wc->restarted = 0;
}
/*
* Reloc tree doesn't contribute to qgroup numbers, and we have
* already accounted them at merge time (replace_path),
* thus we could skip expensive subtree trace here.
*/
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
need_account) {
ret = btrfs_qgroup_trace_subtree(trans, next,
generation, level - 1);
if (ret) {
btrfs_err_rl(fs_info,
"Error %d accounting shared subtree. Quota is out of sync, rescan required.",
ret);
}
}
/*
* We need to update the next key in our walk control so we can
* update the drop_progress key accordingly. We don't care if
* find_next_key doesn't find a key because that means we're at
* the end and are going to clean up now.
*/
wc->drop_level = level;
find_next_key(path, level, &wc->drop_progress);
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
fs_info->nodesize, parent);
btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid);
ret = btrfs_free_extent(trans, &ref);
if (ret)
goto out_unlock;
}
no_delete:
*lookup_info = 1;
ret = 1;
out_unlock:
btrfs_tree_unlock(next);
free_extent_buffer(next);
return ret;
}
/*
* helper to process tree block while walking up the tree.
*
* when wc->stage == DROP_REFERENCE, this function drops
* reference count on the block.
*
* when wc->stage == UPDATE_BACKREF, this function changes
* wc->stage back to DROP_REFERENCE if we changed wc->stage
* to UPDATE_BACKREF previously while processing the block.
*
* NOTE: return value 1 means we should stop walking up.
*/
static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret;
int level = wc->level;
struct extent_buffer *eb = path->nodes[level];
u64 parent = 0;
if (wc->stage == UPDATE_BACKREF) {
BUG_ON(wc->shared_level < level);
if (level < wc->shared_level)
goto out;
ret = find_next_key(path, level + 1, &wc->update_progress);
if (ret > 0)
wc->update_ref = 0;
wc->stage = DROP_REFERENCE;
wc->shared_level = -1;
path->slots[level] = 0;
/*
* check reference count again if the block isn't locked.
* we should start walking down the tree again if reference
* count is one.
*/
if (!path->locks[level]) {
BUG_ON(level == 0);
btrfs_tree_lock(eb);
btrfs_set_lock_blocking_write(eb);
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
&wc->refs[level],
&wc->flags[level]);
if (ret < 0) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
return ret;
}
BUG_ON(wc->refs[level] == 0);
if (wc->refs[level] == 1) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
return 1;
}
}
}
/* wc->stage == DROP_REFERENCE */
BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
if (wc->refs[level] == 1) {
if (level == 0) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
ret = btrfs_dec_ref(trans, root, eb, 1);
else
ret = btrfs_dec_ref(trans, root, eb, 0);
BUG_ON(ret); /* -ENOMEM */
if (is_fstree(root->root_key.objectid)) {
ret = btrfs_qgroup_trace_leaf_items(trans, eb);
if (ret) {
btrfs_err_rl(fs_info,
"error %d accounting leaf items, quota is out of sync, rescan required",
ret);
}
}
}
/* make block locked assertion in btrfs_clean_tree_block happy */
if (!path->locks[level] &&
btrfs_header_generation(eb) == trans->transid) {
btrfs_tree_lock(eb);
btrfs_set_lock_blocking_write(eb);
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
}
btrfs_clean_tree_block(eb);
}
if (eb == root->node) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
parent = eb->start;
else if (root->root_key.objectid != btrfs_header_owner(eb))
goto owner_mismatch;
} else {
if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
parent = path->nodes[level + 1]->start;
else if (root->root_key.objectid !=
btrfs_header_owner(path->nodes[level + 1]))
goto owner_mismatch;
}
btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
out:
wc->refs[level] = 0;
wc->flags[level] = 0;
return 0;
owner_mismatch:
btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
btrfs_header_owner(eb), root->root_key.objectid);
return -EUCLEAN;
}
static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
int level = wc->level;
int lookup_info = 1;
int ret;
while (level >= 0) {
ret = walk_down_proc(trans, root, path, wc, lookup_info);
if (ret > 0)
break;
if (level == 0)
break;
if (path->slots[level] >=
btrfs_header_nritems(path->nodes[level]))
break;
ret = do_walk_down(trans, root, path, wc, &lookup_info);
if (ret > 0) {
path->slots[level]++;
continue;
} else if (ret < 0)
return ret;
level = wc->level;
}
return 0;
}
static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int max_level)
{
int level = wc->level;
int ret;
path->slots[level] = btrfs_header_nritems(path->nodes[level]);
while (level < max_level && path->nodes[level]) {
wc->level = level;
if (path->slots[level] + 1 <
btrfs_header_nritems(path->nodes[level])) {
path->slots[level]++;
return 0;
} else {
ret = walk_up_proc(trans, root, path, wc);
if (ret > 0)
return 0;
if (ret < 0)
return ret;
if (path->locks[level]) {
btrfs_tree_unlock_rw(path->nodes[level],
path->locks[level]);
path->locks[level] = 0;
}
free_extent_buffer(path->nodes[level]);
path->nodes[level] = NULL;
level++;
}
}
return 1;
}
/*
* drop a subvolume tree.
*
* this function traverses the tree freeing any blocks that only
* referenced by the tree.
*
* when a shared tree block is found. this function decreases its
* reference count by one. if update_ref is true, this function
* also make sure backrefs for the shared block and all lower level
* blocks are properly updated.
*
* If called with for_reloc == 0, may exit early with -EAGAIN
*/
int btrfs_drop_snapshot(struct btrfs_root *root,
struct btrfs_block_rsv *block_rsv, int update_ref,
int for_reloc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct btrfs_trans_handle *trans;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root_item *root_item = &root->root_item;
struct walk_control *wc;
struct btrfs_key key;
int err = 0;
int ret;
int level;
bool root_dropped = false;
btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
path = btrfs_alloc_path();
if (!path) {
err = -ENOMEM;
goto out;
}
wc = kzalloc(sizeof(*wc), GFP_NOFS);
if (!wc) {
btrfs_free_path(path);
err = -ENOMEM;
goto out;
}
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
goto out_free;
}
err = btrfs_run_delayed_items(trans);
if (err)
goto out_end_trans;
if (block_rsv)
trans->block_rsv = block_rsv;
/*
* This will help us catch people modifying the fs tree while we're
* dropping it. It is unsafe to mess with the fs tree while it's being
* dropped as we unlock the root node and parent nodes as we walk down
* the tree, assuming nothing will change. If something does change
* then we'll have stale information and drop references to blocks we've
* already dropped.
*/
set_bit(BTRFS_ROOT_DELETING, &root->state);
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_header_level(root->node);
path->nodes[level] = btrfs_lock_root_node(root);
btrfs_set_lock_blocking_write(path->nodes[level]);
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
memset(&wc->update_progress, 0,
sizeof(wc->update_progress));
} else {
btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
memcpy(&wc->update_progress, &key,
sizeof(wc->update_progress));
level = root_item->drop_level;
BUG_ON(level == 0);
path->lowest_level = level;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->lowest_level = 0;
if (ret < 0) {
err = ret;
goto out_end_trans;
}
WARN_ON(ret > 0);
/*
* unlock our path, this is safe because only this
* function is allowed to delete this snapshot
*/
btrfs_unlock_up_safe(path, 0);
level = btrfs_header_level(root->node);
while (1) {
btrfs_tree_lock(path->nodes[level]);
btrfs_set_lock_blocking_write(path->nodes[level]);
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
ret = btrfs_lookup_extent_info(trans, fs_info,
path->nodes[level]->start,
level, 1, &wc->refs[level],
&wc->flags[level]);
if (ret < 0) {
err = ret;
goto out_end_trans;
}
BUG_ON(wc->refs[level] == 0);
if (level == root_item->drop_level)
break;
btrfs_tree_unlock(path->nodes[level]);
path->locks[level] = 0;
WARN_ON(wc->refs[level] != 1);
level--;
}
}
wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
wc->level = level;
wc->shared_level = -1;
wc->stage = DROP_REFERENCE;
wc->update_ref = update_ref;
wc->keep_locks = 0;
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
while (1) {
ret = walk_down_tree(trans, root, path, wc);
if (ret < 0) {
err = ret;
break;
}
ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
if (ret < 0) {
err = ret;
break;
}
if (ret > 0) {
BUG_ON(wc->stage != DROP_REFERENCE);
break;
}
if (wc->stage == DROP_REFERENCE) {
wc->drop_level = wc->level;
btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
&wc->drop_progress,
path->slots[wc->drop_level]);
}
btrfs_cpu_key_to_disk(&root_item->drop_progress,
&wc->drop_progress);
root_item->drop_level = wc->drop_level;
BUG_ON(wc->level == 0);
if (btrfs_should_end_transaction(trans) ||
(!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
root_item);
if (ret) {
btrfs_abort_transaction(trans, ret);
err = ret;
goto out_end_trans;
}
btrfs_end_transaction_throttle(trans);
if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
btrfs_debug(fs_info,
"drop snapshot early exit");
err = -EAGAIN;
goto out_free;
}
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
goto out_free;
}
if (block_rsv)
trans->block_rsv = block_rsv;
}
}
btrfs_release_path(path);
if (err)
goto out_end_trans;
ret = btrfs_del_root(trans, &root->root_key);
if (ret) {
btrfs_abort_transaction(trans, ret);
err = ret;
goto out_end_trans;
}
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
ret = btrfs_find_root(tree_root, &root->root_key, path,
NULL, NULL);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
err = ret;
goto out_end_trans;
} else if (ret > 0) {
/* if we fail to delete the orphan item this time
* around, it'll get picked up the next time.
*
* The most common failure here is just -ENOENT.
*/
btrfs_del_orphan_item(trans, tree_root,
root->root_key.objectid);
}
}
if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
btrfs_add_dropped_root(trans, root);
} else {
free_extent_buffer(root->node);
free_extent_buffer(root->commit_root);
btrfs_put_fs_root(root);
}
root_dropped = true;
out_end_trans:
btrfs_end_transaction_throttle(trans);
out_free:
kfree(wc);
btrfs_free_path(path);
out:
/*
* So if we need to stop dropping the snapshot for whatever reason we
* need to make sure to add it back to the dead root list so that we
* keep trying to do the work later. This also cleans up roots if we
* don't have it in the radix (like when we recover after a power fail
* or unmount) so we don't leak memory.
*/
if (!for_reloc && !root_dropped)
btrfs_add_dead_root(root);
if (err && err != -EAGAIN)
btrfs_handle_fs_error(fs_info, err, NULL);
return err;
}
/*
* drop subtree rooted at tree block 'node'.
*
* NOTE: this function will unlock and release tree block 'node'
* only used by relocation code
*/
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *node,
struct extent_buffer *parent)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct walk_control *wc;
int level;
int parent_level;
int ret = 0;
int wret;
BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
wc = kzalloc(sizeof(*wc), GFP_NOFS);
if (!wc) {
btrfs_free_path(path);
return -ENOMEM;
}
btrfs_assert_tree_locked(parent);
parent_level = btrfs_header_level(parent);
extent_buffer_get(parent);
path->nodes[parent_level] = parent;
path->slots[parent_level] = btrfs_header_nritems(parent);
btrfs_assert_tree_locked(node);
level = btrfs_header_level(node);
path->nodes[level] = node;
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
wc->refs[parent_level] = 1;
wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
wc->level = level;
wc->shared_level = -1;
wc->stage = DROP_REFERENCE;
wc->update_ref = 0;
wc->keep_locks = 1;
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
while (1) {
wret = walk_down_tree(trans, root, path, wc);
if (wret < 0) {
ret = wret;
break;
}
wret = walk_up_tree(trans, root, path, wc, parent_level);
if (wret < 0)
ret = wret;
if (wret != 0)
break;
}
kfree(wc);
btrfs_free_path(path);
return ret;
}
static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 num_devices;
u64 stripped;
/*
* if restripe for this chunk_type is on pick target profile and
* return, otherwise do the usual balance
*/
stripped = get_restripe_target(fs_info, flags);
if (stripped)
return extended_to_chunk(stripped);
num_devices = fs_info->fs_devices->rw_devices;
stripped = BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_RAID1_MASK | BTRFS_BLOCK_GROUP_RAID10;
if (num_devices == 1) {
stripped |= BTRFS_BLOCK_GROUP_DUP;
stripped = flags & ~stripped;
/* turn raid0 into single device chunks */
if (flags & BTRFS_BLOCK_GROUP_RAID0)
return stripped;
/* turn mirroring into duplication */
if (flags & (BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID10))
return stripped | BTRFS_BLOCK_GROUP_DUP;
} else {
/* they already had raid on here, just return */
if (flags & stripped)
return flags;
stripped |= BTRFS_BLOCK_GROUP_DUP;
stripped = flags & ~stripped;
/* switch duplicated blocks with raid1 */
if (flags & BTRFS_BLOCK_GROUP_DUP)
return stripped | BTRFS_BLOCK_GROUP_RAID1;
/* this is drive concat, leave it alone */
}
return flags;
}
/*
* Mark block group @cache read-only, so later write won't happen to block
* group @cache.
*
* If @force is not set, this function will only mark the block group readonly
* if we have enough free space (1M) in other metadata/system block groups.
* If @force is not set, this function will mark the block group readonly
* without checking free space.
*
* NOTE: This function doesn't care if other block groups can contain all the
* data in this block group. That check should be done by relocation routine,
* not this function.
*/
static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
u64 sinfo_used;
u64 min_allocable_bytes;
int ret = -ENOSPC;
/*
* We need some metadata space and system metadata space for
* allocating chunks in some corner cases until we force to set
* it to be readonly.
*/
if ((sinfo->flags &
(BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
!force)
min_allocable_bytes = SZ_1M;
else
min_allocable_bytes = 0;
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
if (cache->ro) {
cache->ro++;
ret = 0;
goto out;
}
num_bytes = cache->key.offset - cache->reserved - cache->pinned -
cache->bytes_super - btrfs_block_group_used(&cache->item);
sinfo_used = btrfs_space_info_used(sinfo, true);
/*
* sinfo_used + num_bytes should always <= sinfo->total_bytes.
*
* Here we make sure if we mark this bg RO, we still have enough
* free space as buffer (if min_allocable_bytes is not 0).
*/
if (sinfo_used + num_bytes + min_allocable_bytes <=
sinfo->total_bytes) {
sinfo->bytes_readonly += num_bytes;
cache->ro++;
list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
ret = 0;
}
out:
spin_unlock(&cache->lock);
spin_unlock(&sinfo->lock);
if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
btrfs_info(cache->fs_info,
"unable to make block group %llu ro",
cache->key.objectid);
btrfs_info(cache->fs_info,
"sinfo_used=%llu bg_num_bytes=%llu min_allocable=%llu",
sinfo_used, num_bytes, min_allocable_bytes);
btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
}
return ret;
}
int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_trans_handle *trans;
u64 alloc_flags;
int ret;
again:
trans = btrfs_join_transaction(fs_info->extent_root);
if (IS_ERR(trans))
return PTR_ERR(trans);
/*
* we're not allowed to set block groups readonly after the dirty
* block groups cache has started writing. If it already started,
* back off and let this transaction commit
*/
mutex_lock(&fs_info->ro_block_group_mutex);
if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
u64 transid = trans->transid;
mutex_unlock(&fs_info->ro_block_group_mutex);
btrfs_end_transaction(trans);
ret = btrfs_wait_for_commit(fs_info, transid);
if (ret)
return ret;
goto again;
}
/*
* if we are changing raid levels, try to allocate a corresponding
* block group with the new raid level.
*/
alloc_flags = update_block_group_flags(fs_info, cache->flags);
if (alloc_flags != cache->flags) {
ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
/*
* ENOSPC is allowed here, we may have enough space
* already allocated at the new raid level to
* carry on
*/
if (ret == -ENOSPC)
ret = 0;
if (ret < 0)
goto out;
}
ret = inc_block_group_ro(cache, 0);
if (!ret)
goto out;
alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
if (ret < 0)
goto out;
ret = inc_block_group_ro(cache, 0);
out:
if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
alloc_flags = update_block_group_flags(fs_info, cache->flags);
mutex_lock(&fs_info->chunk_mutex);
check_system_chunk(trans, alloc_flags);
mutex_unlock(&fs_info->chunk_mutex);
}
mutex_unlock(&fs_info->ro_block_group_mutex);
btrfs_end_transaction(trans);
return ret;
}
int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
{
u64 alloc_flags = get_alloc_profile(trans->fs_info, type);
return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
}
/*
* helper to account the unused space of all the readonly block group in the
* space_info. takes mirrors into account.
*/
u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
{
struct btrfs_block_group_cache *block_group;
u64 free_bytes = 0;
int factor;
/* It's df, we don't care if it's racy */
if (list_empty(&sinfo->ro_bgs))
return 0;
spin_lock(&sinfo->lock);
list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
spin_lock(&block_group->lock);
if (!block_group->ro) {
spin_unlock(&block_group->lock);
continue;
}
factor = btrfs_bg_type_to_factor(block_group->flags);
free_bytes += (block_group->key.offset -
btrfs_block_group_used(&block_group->item)) *
factor;
spin_unlock(&block_group->lock);
}
spin_unlock(&sinfo->lock);
return free_bytes;
}
void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
BUG_ON(!cache->ro);
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
if (!--cache->ro) {
num_bytes = cache->key.offset - cache->reserved -
cache->pinned - cache->bytes_super -
btrfs_block_group_used(&cache->item);
sinfo->bytes_readonly -= num_bytes;
list_del_init(&cache->ro_list);
}
spin_unlock(&cache->lock);
spin_unlock(&sinfo->lock);
}
static int find_first_block_group(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_root *root = fs_info->extent_root;
int ret = 0;
struct btrfs_key found_key;
struct extent_buffer *leaf;
struct btrfs_block_group_item bg;
u64 flags;
int slot;
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
slot = path->slots[0];
leaf = path->nodes[0];
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto out;
break;
}
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid >= key->objectid &&
found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
struct extent_map_tree *em_tree;
struct extent_map *em;
em_tree = &root->fs_info->mapping_tree;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, found_key.objectid,
found_key.offset);
read_unlock(&em_tree->lock);
if (!em) {
btrfs_err(fs_info,
"logical %llu len %llu found bg but no related chunk",
found_key.objectid, found_key.offset);
ret = -ENOENT;
} else if (em->start != found_key.objectid ||
em->len != found_key.offset) {
btrfs_err(fs_info,
"block group %llu len %llu mismatch with chunk %llu len %llu",
found_key.objectid, found_key.offset,
em->start, em->len);
ret = -EUCLEAN;
} else {
read_extent_buffer(leaf, &bg,
btrfs_item_ptr_offset(leaf, slot),
sizeof(bg));
flags = btrfs_block_group_flags(&bg) &
BTRFS_BLOCK_GROUP_TYPE_MASK;
if (flags != (em->map_lookup->type &
BTRFS_BLOCK_GROUP_TYPE_MASK)) {
btrfs_err(fs_info,
"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
found_key.objectid,
found_key.offset, flags,
(BTRFS_BLOCK_GROUP_TYPE_MASK &
em->map_lookup->type));
ret = -EUCLEAN;
} else {
ret = 0;
}
}
free_extent_map(em);
goto out;
}
path->slots[0]++;
}
out:
return ret;
}
void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
{
struct btrfs_block_group_cache *block_group;
u64 last = 0;
while (1) {
struct inode *inode;
block_group = btrfs_lookup_first_block_group(info, last);
while (block_group) {
btrfs_wait_block_group_cache_done(block_group);
spin_lock(&block_group->lock);
if (block_group->iref)
break;
spin_unlock(&block_group->lock);
block_group = btrfs_next_block_group(block_group);
}
if (!block_group) {
if (last == 0)
break;
last = 0;
continue;
}
inode = block_group->inode;
block_group->iref = 0;
block_group->inode = NULL;
spin_unlock(&block_group->lock);
ASSERT(block_group->io_ctl.inode == NULL);
iput(inode);
last = block_group->key.objectid + block_group->key.offset;
btrfs_put_block_group(block_group);
}
}
/*
* Must be called only after stopping all workers, since we could have block
* group caching kthreads running, and therefore they could race with us if we
* freed the block groups before stopping them.
*/
int btrfs_free_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
struct btrfs_caching_control *caching_ctl;
struct rb_node *n;
down_write(&info->commit_root_sem);
while (!list_empty(&info->caching_block_groups)) {
caching_ctl = list_entry(info->caching_block_groups.next,
struct btrfs_caching_control, list);
list_del(&caching_ctl->list);
btrfs_put_caching_control(caching_ctl);
}
up_write(&info->commit_root_sem);
spin_lock(&info->unused_bgs_lock);
while (!list_empty(&info->unused_bgs)) {
block_group = list_first_entry(&info->unused_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&block_group->bg_list);
btrfs_put_block_group(block_group);
}
spin_unlock(&info->unused_bgs_lock);
spin_lock(&info->block_group_cache_lock);
while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
block_group = rb_entry(n, struct btrfs_block_group_cache,
cache_node);
rb_erase(&block_group->cache_node,
&info->block_group_cache_tree);
RB_CLEAR_NODE(&block_group->cache_node);
spin_unlock(&info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
list_del(&block_group->list);
up_write(&block_group->space_info->groups_sem);
/*
* We haven't cached this block group, which means we could
* possibly have excluded extents on this block group.
*/
if (block_group->cached == BTRFS_CACHE_NO ||
block_group->cached == BTRFS_CACHE_ERROR)
btrfs_free_excluded_extents(block_group);
btrfs_remove_free_space_cache(block_group);
ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
ASSERT(list_empty(&block_group->dirty_list));
ASSERT(list_empty(&block_group->io_list));
ASSERT(list_empty(&block_group->bg_list));
ASSERT(atomic_read(&block_group->count) == 1);
btrfs_put_block_group(block_group);
spin_lock(&info->block_group_cache_lock);
}
spin_unlock(&info->block_group_cache_lock);
/* now that all the block groups are freed, go through and
* free all the space_info structs. This is only called during
* the final stages of unmount, and so we know nobody is
* using them. We call synchronize_rcu() once before we start,
* just to be on the safe side.
*/
synchronize_rcu();
btrfs_release_global_block_rsv(info);
while (!list_empty(&info->space_info)) {
int i;
space_info = list_entry(info->space_info.next,
struct btrfs_space_info,
list);
/*
* Do not hide this behind enospc_debug, this is actually
* important and indicates a real bug if this happens.
*/
if (WARN_ON(space_info->bytes_pinned > 0 ||
space_info->bytes_reserved > 0 ||
space_info->bytes_may_use > 0))
btrfs_dump_space_info(info, space_info, 0, 0);
list_del(&space_info->list);
for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
struct kobject *kobj;
kobj = space_info->block_group_kobjs[i];
space_info->block_group_kobjs[i] = NULL;
if (kobj) {
kobject_del(kobj);
kobject_put(kobj);
}
}
kobject_del(&space_info->kobj);
kobject_put(&space_info->kobj);
}
return 0;
}
static void link_block_group(struct btrfs_block_group_cache *cache)
{
struct btrfs_space_info *space_info = cache->space_info;
int index = btrfs_bg_flags_to_raid_index(cache->flags);
bool first = false;
down_write(&space_info->groups_sem);
if (list_empty(&space_info->block_groups[index]))
first = true;
list_add_tail(&cache->list, &space_info->block_groups[index]);
up_write(&space_info->groups_sem);
if (first)
btrfs_sysfs_add_block_group_type(cache);
}
static struct btrfs_block_group_cache *
btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
u64 start, u64 size)
{
struct btrfs_block_group_cache *cache;
cache = kzalloc(sizeof(*cache), GFP_NOFS);
if (!cache)
return NULL;
cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
GFP_NOFS);
if (!cache->free_space_ctl) {
kfree(cache);
return NULL;
}
cache->key.objectid = start;
cache->key.offset = size;
cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
cache->fs_info = fs_info;
cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
set_free_space_tree_thresholds(cache);
atomic_set(&cache->count, 1);
spin_lock_init(&cache->lock);
init_rwsem(&cache->data_rwsem);
INIT_LIST_HEAD(&cache->list);
INIT_LIST_HEAD(&cache->cluster_list);
INIT_LIST_HEAD(&cache->bg_list);
INIT_LIST_HEAD(&cache->ro_list);
INIT_LIST_HEAD(&cache->dirty_list);
INIT_LIST_HEAD(&cache->io_list);
btrfs_init_free_space_ctl(cache);
atomic_set(&cache->trimming, 0);
mutex_init(&cache->free_space_lock);
btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
return cache;
}
/*
* Iterate all chunks and verify that each of them has the corresponding block
* group
*/
static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
{
struct extent_map_tree *map_tree = &fs_info->mapping_tree;
struct extent_map *em;
struct btrfs_block_group_cache *bg;
u64 start = 0;
int ret = 0;
while (1) {
read_lock(&map_tree->lock);
/*
* lookup_extent_mapping will return the first extent map
* intersecting the range, so setting @len to 1 is enough to
* get the first chunk.
*/
em = lookup_extent_mapping(map_tree, start, 1);
read_unlock(&map_tree->lock);
if (!em)
break;
bg = btrfs_lookup_block_group(fs_info, em->start);
if (!bg) {
btrfs_err(fs_info,
"chunk start=%llu len=%llu doesn't have corresponding block group",
em->start, em->len);
ret = -EUCLEAN;
free_extent_map(em);
break;
}
if (bg->key.objectid != em->start ||
bg->key.offset != em->len ||
(bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
(em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
btrfs_err(fs_info,
"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
em->start, em->len,
em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
bg->key.objectid, bg->key.offset,
bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
ret = -EUCLEAN;
free_extent_map(em);
btrfs_put_block_group(bg);
break;
}
start = em->start + em->len;
free_extent_map(em);
btrfs_put_block_group(bg);
}
return ret;
}
int btrfs_read_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_path *path;
int ret;
struct btrfs_block_group_cache *cache;
struct btrfs_space_info *space_info;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *leaf;
int need_clear = 0;
u64 cache_gen;
u64 feature;
int mixed;
feature = btrfs_super_incompat_flags(info->super_copy);
mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
key.objectid = 0;
key.offset = 0;
key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
cache_gen = btrfs_super_cache_generation(info->super_copy);
if (btrfs_test_opt(info, SPACE_CACHE) &&
btrfs_super_generation(info->super_copy) != cache_gen)
need_clear = 1;
if (btrfs_test_opt(info, CLEAR_CACHE))
need_clear = 1;
while (1) {
ret = find_first_block_group(info, path, &key);
if (ret > 0)
break;
if (ret != 0)
goto error;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
cache = btrfs_create_block_group_cache(info, found_key.objectid,
found_key.offset);
if (!cache) {
ret = -ENOMEM;
goto error;
}
if (need_clear) {
/*
* When we mount with old space cache, we need to
* set BTRFS_DC_CLEAR and set dirty flag.
*
* a) Setting 'BTRFS_DC_CLEAR' makes sure that we
* truncate the old free space cache inode and
* setup a new one.
* b) Setting 'dirty flag' makes sure that we flush
* the new space cache info onto disk.
*/
if (btrfs_test_opt(info, SPACE_CACHE))
cache->disk_cache_state = BTRFS_DC_CLEAR;
}
read_extent_buffer(leaf, &cache->item,
btrfs_item_ptr_offset(leaf, path->slots[0]),
sizeof(cache->item));
cache->flags = btrfs_block_group_flags(&cache->item);
if (!mixed &&
((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
(cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
btrfs_err(info,
"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
cache->key.objectid);
ret = -EINVAL;
goto error;
}
key.objectid = found_key.objectid + found_key.offset;
btrfs_release_path(path);
/*
* We need to exclude the super stripes now so that the space
* info has super bytes accounted for, otherwise we'll think
* we have more space than we actually do.
*/
ret = exclude_super_stripes(cache);
if (ret) {
/*
* We may have excluded something, so call this just in
* case.
*/
btrfs_free_excluded_extents(cache);
btrfs_put_block_group(cache);
goto error;
}
/*
* check for two cases, either we are full, and therefore
* don't need to bother with the caching work since we won't
* find any space, or we are empty, and we can just add all
* the space in and be done with it. This saves us _a_lot_ of
* time, particularly in the full case.
*/
if (found_key.offset == btrfs_block_group_used(&cache->item)) {
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
btrfs_free_excluded_extents(cache);
} else if (btrfs_block_group_used(&cache->item) == 0) {
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
add_new_free_space(cache, found_key.objectid,
found_key.objectid +
found_key.offset);
btrfs_free_excluded_extents(cache);
}
ret = btrfs_add_block_group_cache(info, cache);
if (ret) {
btrfs_remove_free_space_cache(cache);
btrfs_put_block_group(cache);
goto error;
}
trace_btrfs_add_block_group(info, cache, 0);
btrfs_update_space_info(info, cache->flags, found_key.offset,
btrfs_block_group_used(&cache->item),
cache->bytes_super, &space_info);
cache->space_info = space_info;
link_block_group(cache);
set_avail_alloc_bits(info, cache->flags);
if (btrfs_chunk_readonly(info, cache->key.objectid)) {
inc_block_group_ro(cache, 1);
} else if (btrfs_block_group_used(&cache->item) == 0) {
ASSERT(list_empty(&cache->bg_list));
btrfs_mark_bg_unused(cache);
}
}
list_for_each_entry_rcu(space_info, &info->space_info, list) {
if (!(get_alloc_profile(info, space_info->flags) &
(BTRFS_BLOCK_GROUP_RAID10 |
BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_DUP)))
continue;
/*
* avoid allocating from un-mirrored block group if there are
* mirrored block groups.
*/
list_for_each_entry(cache,
&space_info->block_groups[BTRFS_RAID_RAID0],
list)
inc_block_group_ro(cache, 1);
list_for_each_entry(cache,
&space_info->block_groups[BTRFS_RAID_SINGLE],
list)
inc_block_group_ro(cache, 1);
}
btrfs_init_global_block_rsv(info);
ret = check_chunk_block_group_mappings(info);
error:
btrfs_free_path(path);
return ret;
}
void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *block_group;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_block_group_item item;
struct btrfs_key key;
int ret = 0;
if (!trans->can_flush_pending_bgs)
return;
while (!list_empty(&trans->new_bgs)) {
block_group = list_first_entry(&trans->new_bgs,
struct btrfs_block_group_cache,
bg_list);
if (ret)
goto next;
spin_lock(&block_group->lock);
memcpy(&item, &block_group->item, sizeof(item));
memcpy(&key, &block_group->key, sizeof(key));
spin_unlock(&block_group->lock);
ret = btrfs_insert_item(trans, extent_root, &key, &item,
sizeof(item));
if (ret)
btrfs_abort_transaction(trans, ret);
ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
if (ret)
btrfs_abort_transaction(trans, ret);
add_block_group_free_space(trans, block_group);
/* already aborted the transaction if it failed. */
next:
btrfs_delayed_refs_rsv_release(fs_info, 1);
list_del_init(&block_group->bg_list);
}
btrfs_trans_release_chunk_metadata(trans);
}
int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
u64 type, u64 chunk_offset, u64 size)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
int ret;
btrfs_set_log_full_commit(trans);
cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
if (!cache)
return -ENOMEM;
btrfs_set_block_group_used(&cache->item, bytes_used);
btrfs_set_block_group_chunk_objectid(&cache->item,
BTRFS_FIRST_CHUNK_TREE_OBJECTID);
btrfs_set_block_group_flags(&cache->item, type);
cache->flags = type;
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
cache->needs_free_space = 1;
ret = exclude_super_stripes(cache);
if (ret) {
/*
* We may have excluded something, so call this just in
* case.
*/
btrfs_free_excluded_extents(cache);
btrfs_put_block_group(cache);
return ret;
}
add_new_free_space(cache, chunk_offset, chunk_offset + size);
btrfs_free_excluded_extents(cache);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(cache)) {
u64 new_bytes_used = size - bytes_used;
bytes_used += new_bytes_used >> 1;
btrfs_fragment_free_space(cache);
}
#endif
/*
* Ensure the corresponding space_info object is created and
* assigned to our block group. We want our bg to be added to the rbtree
* with its ->space_info set.
*/
cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
ASSERT(cache->space_info);
ret = btrfs_add_block_group_cache(fs_info, cache);
if (ret) {
btrfs_remove_free_space_cache(cache);
btrfs_put_block_group(cache);
return ret;
}
/*
* Now that our block group has its ->space_info set and is inserted in
* the rbtree, update the space info's counters.
*/
trace_btrfs_add_block_group(fs_info, cache, 1);
btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
cache->bytes_super, &cache->space_info);
btrfs_update_global_block_rsv(fs_info);
link_block_group(cache);
list_add_tail(&cache->bg_list, &trans->new_bgs);
trans->delayed_ref_updates++;
btrfs_update_delayed_refs_rsv(trans);
set_avail_alloc_bits(fs_info, type);
return 0;
}
static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = chunk_to_extended(flags) &
BTRFS_EXTENDED_PROFILE_MASK;
write_seqlock(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
fs_info->avail_data_alloc_bits &= ~extra_flags;
if (flags & BTRFS_BLOCK_GROUP_METADATA)
fs_info->avail_metadata_alloc_bits &= ~extra_flags;
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
fs_info->avail_system_alloc_bits &= ~extra_flags;
write_sequnlock(&fs_info->profiles_lock);
}
/*
* Clear incompat bits for the following feature(s):
*
* - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
* in the whole filesystem
*/
static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
if (flags & BTRFS_BLOCK_GROUP_RAID56_MASK) {
struct list_head *head = &fs_info->space_info;
struct btrfs_space_info *sinfo;
list_for_each_entry_rcu(sinfo, head, list) {
bool found = false;
down_read(&sinfo->groups_sem);
if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
found = true;
if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
found = true;
up_read(&sinfo->groups_sem);
if (found)
return;
}
btrfs_clear_fs_incompat(fs_info, RAID56);
}
}
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
u64 group_start, struct extent_map *em)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_path *path;
struct btrfs_block_group_cache *block_group;
struct btrfs_free_cluster *cluster;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_key key;
struct inode *inode;
struct kobject *kobj = NULL;
int ret;
int index;
int factor;
struct btrfs_caching_control *caching_ctl = NULL;
bool remove_em;
bool remove_rsv = false;
block_group = btrfs_lookup_block_group(fs_info, group_start);
BUG_ON(!block_group);
BUG_ON(!block_group->ro);
trace_btrfs_remove_block_group(block_group);
/*
* Free the reserved super bytes from this block group before
* remove it.
*/
btrfs_free_excluded_extents(block_group);
btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
block_group->key.offset);
memcpy(&key, &block_group->key, sizeof(key));
index = btrfs_bg_flags_to_raid_index(block_group->flags);
factor = btrfs_bg_type_to_factor(block_group->flags);
/* make sure this block group isn't part of an allocation cluster */
cluster = &fs_info->data_alloc_cluster;
spin_lock(&cluster->refill_lock);
btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&cluster->refill_lock);
/*
* make sure this block group isn't part of a metadata
* allocation cluster
*/
cluster = &fs_info->meta_alloc_cluster;
spin_lock(&cluster->refill_lock);
btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&cluster->refill_lock);
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
/*
* get the inode first so any iput calls done for the io_list
* aren't the final iput (no unlinks allowed now)
*/
inode = lookup_free_space_inode(block_group, path);
mutex_lock(&trans->transaction->cache_write_mutex);
/*
* Make sure our free space cache IO is done before removing the
* free space inode
*/
spin_lock(&trans->transaction->dirty_bgs_lock);
if (!list_empty(&block_group->io_list)) {
list_del_init(&block_group->io_list);
WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
spin_unlock(&trans->transaction->dirty_bgs_lock);
btrfs_wait_cache_io(trans, block_group, path);
btrfs_put_block_group(block_group);
spin_lock(&trans->transaction->dirty_bgs_lock);
}
if (!list_empty(&block_group->dirty_list)) {
list_del_init(&block_group->dirty_list);
remove_rsv = true;
btrfs_put_block_group(block_group);
}
spin_unlock(&trans->transaction->dirty_bgs_lock);
mutex_unlock(&trans->transaction->cache_write_mutex);
if (!IS_ERR(inode)) {
ret = btrfs_orphan_add(trans, BTRFS_I(inode));
if (ret) {
btrfs_add_delayed_iput(inode);
goto out;
}
clear_nlink(inode);
/* One for the block groups ref */
spin_lock(&block_group->lock);
if (block_group->iref) {
block_group->iref = 0;
block_group->inode = NULL;
spin_unlock(&block_group->lock);
iput(inode);
} else {
spin_unlock(&block_group->lock);
}
/* One for our lookup ref */
btrfs_add_delayed_iput(inode);
}
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.offset = block_group->key.objectid;
key.type = 0;
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0)
btrfs_release_path(path);
if (ret == 0) {
ret = btrfs_del_item(trans, tree_root, path);
if (ret)
goto out;
btrfs_release_path(path);
}
spin_lock(&fs_info->block_group_cache_lock);
rb_erase(&block_group->cache_node,
&fs_info->block_group_cache_tree);
RB_CLEAR_NODE(&block_group->cache_node);
if (fs_info->first_logical_byte == block_group->key.objectid)
fs_info->first_logical_byte = (u64)-1;
spin_unlock(&fs_info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
/*
* we must use list_del_init so people can check to see if they
* are still on the list after taking the semaphore
*/
list_del_init(&block_group->list);
if (list_empty(&block_group->space_info->block_groups[index])) {
kobj = block_group->space_info->block_group_kobjs[index];
block_group->space_info->block_group_kobjs[index] = NULL;
clear_avail_alloc_bits(fs_info, block_group->flags);
}
up_write(&block_group->space_info->groups_sem);
clear_incompat_bg_bits(fs_info, block_group->flags);
if (kobj) {
kobject_del(kobj);
kobject_put(kobj);
}
if (block_group->has_caching_ctl)
caching_ctl = btrfs_get_caching_control(block_group);
if (block_group->cached == BTRFS_CACHE_STARTED)
btrfs_wait_block_group_cache_done(block_group);
if (block_group->has_caching_ctl) {
down_write(&fs_info->commit_root_sem);
if (!caching_ctl) {
struct btrfs_caching_control *ctl;
list_for_each_entry(ctl,
&fs_info->caching_block_groups, list)
if (ctl->block_group == block_group) {
caching_ctl = ctl;
refcount_inc(&caching_ctl->count);
break;
}
}
if (caching_ctl)
list_del_init(&caching_ctl->list);
up_write(&fs_info->commit_root_sem);
if (caching_ctl) {
/* Once for the caching bgs list and once for us. */
btrfs_put_caching_control(caching_ctl);
btrfs_put_caching_control(caching_ctl);
}
}
spin_lock(&trans->transaction->dirty_bgs_lock);
WARN_ON(!list_empty(&block_group->dirty_list));
WARN_ON(!list_empty(&block_group->io_list));
spin_unlock(&trans->transaction->dirty_bgs_lock);
btrfs_remove_free_space_cache(block_group);
spin_lock(&block_group->space_info->lock);
list_del_init(&block_group->ro_list);
if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
WARN_ON(block_group->space_info->total_bytes
< block_group->key.offset);
WARN_ON(block_group->space_info->bytes_readonly
< block_group->key.offset);
WARN_ON(block_group->space_info->disk_total
< block_group->key.offset * factor);
}
block_group->space_info->total_bytes -= block_group->key.offset;
block_group->space_info->bytes_readonly -= block_group->key.offset;
block_group->space_info->disk_total -= block_group->key.offset * factor;
spin_unlock(&block_group->space_info->lock);
memcpy(&key, &block_group->key, sizeof(key));
mutex_lock(&fs_info->chunk_mutex);
spin_lock(&block_group->lock);
block_group->removed = 1;
/*
* At this point trimming can't start on this block group, because we
* removed the block group from the tree fs_info->block_group_cache_tree
* so no one can't find it anymore and even if someone already got this
* block group before we removed it from the rbtree, they have already
* incremented block_group->trimming - if they didn't, they won't find
* any free space entries because we already removed them all when we
* called btrfs_remove_free_space_cache().
*
* And we must not remove the extent map from the fs_info->mapping_tree
* to prevent the same logical address range and physical device space
* ranges from being reused for a new block group. This is because our
* fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
* completely transactionless, so while it is trimming a range the
* currently running transaction might finish and a new one start,
* allowing for new block groups to be created that can reuse the same
* physical device locations unless we take this special care.
*
* There may also be an implicit trim operation if the file system
* is mounted with -odiscard. The same protections must remain
* in place until the extents have been discarded completely when
* the transaction commit has completed.
*/
remove_em = (atomic_read(&block_group->trimming) == 0);
spin_unlock(&block_group->lock);
mutex_unlock(&fs_info->chunk_mutex);
ret = remove_block_group_free_space(trans, block_group);
if (ret)
goto out;
btrfs_put_block_group(block_group);
btrfs_put_block_group(block_group);
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -EIO;
if (ret < 0)
goto out;
ret = btrfs_del_item(trans, root, path);
if (ret)
goto out;
if (remove_em) {
struct extent_map_tree *em_tree;
em_tree = &fs_info->mapping_tree;
write_lock(&em_tree->lock);
remove_extent_mapping(em_tree, em);
write_unlock(&em_tree->lock);
/* once for the tree */
free_extent_map(em);
}
out:
if (remove_rsv)
btrfs_delayed_refs_rsv_release(fs_info, 1);
btrfs_free_path(path);
return ret;
}
struct btrfs_trans_handle *
btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
const u64 chunk_offset)
{
struct extent_map_tree *em_tree = &fs_info->mapping_tree;
struct extent_map *em;
struct map_lookup *map;
unsigned int num_items;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, chunk_offset, 1);
read_unlock(&em_tree->lock);
ASSERT(em && em->start == chunk_offset);
/*
* We need to reserve 3 + N units from the metadata space info in order
* to remove a block group (done at btrfs_remove_chunk() and at
* btrfs_remove_block_group()), which are used for:
*
* 1 unit for adding the free space inode's orphan (located in the tree
* of tree roots).
* 1 unit for deleting the block group item (located in the extent
* tree).
* 1 unit for deleting the free space item (located in tree of tree
* roots).
* N units for deleting N device extent items corresponding to each
* stripe (located in the device tree).
*
* In order to remove a block group we also need to reserve units in the
* system space info in order to update the chunk tree (update one or
* more device items and remove one chunk item), but this is done at
* btrfs_remove_chunk() through a call to check_system_chunk().
*/
map = em->map_lookup;
num_items = 3 + map->num_stripes;
free_extent_map(em);
return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
num_items, 1);
}
/*
* Process the unused_bgs list and remove any that don't have any allocated
* space inside of them.
*/
void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
struct btrfs_trans_handle *trans;
int ret = 0;
if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
return;
spin_lock(&fs_info->unused_bgs_lock);
while (!list_empty(&fs_info->unused_bgs)) {
u64 start, end;
int trimming;
block_group = list_first_entry(&fs_info->unused_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&block_group->bg_list);
space_info = block_group->space_info;
if (ret || btrfs_mixed_space_info(space_info)) {
btrfs_put_block_group(block_group);
continue;
}
spin_unlock(&fs_info->unused_bgs_lock);
mutex_lock(&fs_info->delete_unused_bgs_mutex);
/* Don't want to race with allocators so take the groups_sem */
down_write(&space_info->groups_sem);
spin_lock(&block_group->lock);
if (block_group->reserved || block_group->pinned ||
btrfs_block_group_used(&block_group->item) ||
block_group->ro ||
list_is_singular(&block_group->list)) {
/*
* We want to bail if we made new allocations or have
* outstanding allocations in this block group. We do
* the ro check in case balance is currently acting on
* this block group.
*/
trace_btrfs_skip_unused_block_group(block_group);
spin_unlock(&block_group->lock);
up_write(&space_info->groups_sem);
goto next;
}
spin_unlock(&block_group->lock);
/* We don't want to force the issue, only flip if it's ok. */
ret = inc_block_group_ro(block_group, 0);
up_write(&space_info->groups_sem);
if (ret < 0) {
ret = 0;
goto next;
}
/*
* Want to do this before we do anything else so we can recover
* properly if we fail to join the transaction.
*/
trans = btrfs_start_trans_remove_block_group(fs_info,
block_group->key.objectid);
if (IS_ERR(trans)) {
btrfs_dec_block_group_ro(block_group);
ret = PTR_ERR(trans);
goto next;
}
/*
* We could have pending pinned extents for this block group,
* just delete them, we don't care about them anymore.
*/
start = block_group->key.objectid;
end = start + block_group->key.offset - 1;
/*
* Hold the unused_bg_unpin_mutex lock to avoid racing with
* btrfs_finish_extent_commit(). If we are at transaction N,
* another task might be running finish_extent_commit() for the
* previous transaction N - 1, and have seen a range belonging
* to the block group in freed_extents[] before we were able to
* clear the whole block group range from freed_extents[]. This
* means that task can lookup for the block group after we
* unpinned it from freed_extents[] and removed it, leading to
* a BUG_ON() at btrfs_unpin_extent_range().
*/
mutex_lock(&fs_info->unused_bg_unpin_mutex);
ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
EXTENT_DIRTY);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
btrfs_dec_block_group_ro(block_group);
goto end_trans;
}
ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
EXTENT_DIRTY);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
btrfs_dec_block_group_ro(block_group);
goto end_trans;
}
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
/* Reset pinned so btrfs_put_block_group doesn't complain */
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
btrfs_space_info_update_bytes_pinned(fs_info, space_info,
-block_group->pinned);
space_info->bytes_readonly += block_group->pinned;
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-block_group->pinned,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
block_group->pinned = 0;
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
/* DISCARD can flip during remount */
trimming = btrfs_test_opt(fs_info, DISCARD);
/* Implicit trim during transaction commit. */
if (trimming)
btrfs_get_block_group_trimming(block_group);
/*
* Btrfs_remove_chunk will abort the transaction if things go
* horribly wrong.
*/
ret = btrfs_remove_chunk(trans, block_group->key.objectid);
if (ret) {
if (trimming)
btrfs_put_block_group_trimming(block_group);
goto end_trans;
}
/*
* If we're not mounted with -odiscard, we can just forget
* about this block group. Otherwise we'll need to wait
* until transaction commit to do the actual discard.
*/
if (trimming) {
spin_lock(&fs_info->unused_bgs_lock);
/*
* A concurrent scrub might have added us to the list
* fs_info->unused_bgs, so use a list_move operation
* to add the block group to the deleted_bgs list.
*/
list_move(&block_group->bg_list,
&trans->transaction->deleted_bgs);
spin_unlock(&fs_info->unused_bgs_lock);
btrfs_get_block_group(block_group);
}
end_trans:
btrfs_end_transaction(trans);
next:
mutex_unlock(&fs_info->delete_unused_bgs_mutex);
btrfs_put_block_group(block_group);
spin_lock(&fs_info->unused_bgs_lock);
}
spin_unlock(&fs_info->unused_bgs_lock);
}
int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
u64 start, u64 end)
{
return unpin_extent_range(fs_info, start, end, false);
}
/*
* It used to be that old block groups would be left around forever.
* Iterating over them would be enough to trim unused space. Since we
* now automatically remove them, we also need to iterate over unallocated
* space.
*
* We don't want a transaction for this since the discard may take a
* substantial amount of time. We don't require that a transaction be
* running, but we do need to take a running transaction into account
* to ensure that we're not discarding chunks that were released or
* allocated in the current transaction.
*
* Holding the chunks lock will prevent other threads from allocating
* or releasing chunks, but it won't prevent a running transaction
* from committing and releasing the memory that the pending chunks
* list head uses. For that, we need to take a reference to the
* transaction and hold the commit root sem. We only need to hold
* it while performing the free space search since we have already
* held back allocations.
*/
static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
{
u64 start = SZ_1M, len = 0, end = 0;
int ret;
*trimmed = 0;
/* Discard not supported = nothing to do. */
if (!blk_queue_discard(bdev_get_queue(device->bdev)))
return 0;
/* Not writable = nothing to do. */
if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
return 0;
/* No free space = nothing to do. */
if (device->total_bytes <= device->bytes_used)
return 0;
ret = 0;
while (1) {
struct btrfs_fs_info *fs_info = device->fs_info;
u64 bytes;
ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
if (ret)
break;
find_first_clear_extent_bit(&device->alloc_state, start,
&start, &end,
CHUNK_TRIMMED | CHUNK_ALLOCATED);
/* Ensure we skip the reserved area in the first 1M */
start = max_t(u64, start, SZ_1M);
/*
* If find_first_clear_extent_bit find a range that spans the
* end of the device it will set end to -1, in this case it's up
* to the caller to trim the value to the size of the device.
*/
end = min(end, device->total_bytes - 1);
len = end - start + 1;
/* We didn't find any extents */
if (!len) {
mutex_unlock(&fs_info->chunk_mutex);
ret = 0;
break;
}
ret = btrfs_issue_discard(device->bdev, start, len,
&bytes);
if (!ret)
set_extent_bits(&device->alloc_state, start,
start + bytes - 1,
CHUNK_TRIMMED);
mutex_unlock(&fs_info->chunk_mutex);
if (ret)
break;
start += len;
*trimmed += bytes;
if (fatal_signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
cond_resched();
}
return ret;
}
/*
* Trim the whole filesystem by:
* 1) trimming the free space in each block group
* 2) trimming the unallocated space on each device
*
* This will also continue trimming even if a block group or device encounters
* an error. The return value will be the last error, or 0 if nothing bad
* happens.
*/
int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
{
struct btrfs_block_group_cache *cache = NULL;
struct btrfs_device *device;
struct list_head *devices;
u64 group_trimmed;
u64 range_end = U64_MAX;
u64 start;
u64 end;
u64 trimmed = 0;
u64 bg_failed = 0;
u64 dev_failed = 0;
int bg_ret = 0;
int dev_ret = 0;
int ret = 0;
/*
* Check range overflow if range->len is set.
* The default range->len is U64_MAX.
*/
if (range->len != U64_MAX &&
check_add_overflow(range->start, range->len, &range_end))
return -EINVAL;
cache = btrfs_lookup_first_block_group(fs_info, range->start);
for (; cache; cache = btrfs_next_block_group(cache)) {
if (cache->key.objectid >= range_end) {
btrfs_put_block_group(cache);
break;
}
start = max(range->start, cache->key.objectid);
end = min(range_end, cache->key.objectid + cache->key.offset);
if (end - start >= range->minlen) {
if (!btrfs_block_group_cache_done(cache)) {
ret = btrfs_cache_block_group(cache, 0);
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
ret = btrfs_wait_block_group_cache_done(cache);
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
}
ret = btrfs_trim_block_group(cache,
&group_trimmed,
start,
end,
range->minlen);
trimmed += group_trimmed;
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
}
}
if (bg_failed)
btrfs_warn(fs_info,
"failed to trim %llu block group(s), last error %d",
bg_failed, bg_ret);
mutex_lock(&fs_info->fs_devices->device_list_mutex);
devices = &fs_info->fs_devices->devices;
list_for_each_entry(device, devices, dev_list) {
ret = btrfs_trim_free_extents(device, &group_trimmed);
if (ret) {
dev_failed++;
dev_ret = ret;
break;
}
trimmed += group_trimmed;
}
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
if (dev_failed)
btrfs_warn(fs_info,
"failed to trim %llu device(s), last error %d",
dev_failed, dev_ret);
range->len = trimmed;
if (bg_ret)
return bg_ret;
return dev_ret;
}
/*
* btrfs_{start,end}_write_no_snapshotting() are similar to
* mnt_{want,drop}_write(), they are used to prevent some tasks from writing
* data into the page cache through nocow before the subvolume is snapshoted,
* but flush the data into disk after the snapshot creation, or to prevent
* operations while snapshotting is ongoing and that cause the snapshot to be
* inconsistent (writes followed by expanding truncates for example).
*/
void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
{
percpu_counter_dec(&root->subv_writers->counter);
cond_wake_up(&root->subv_writers->wait);
}
int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
{
if (atomic_read(&root->will_be_snapshotted))
return 0;
percpu_counter_inc(&root->subv_writers->counter);
/*
* Make sure counter is updated before we check for snapshot creation.
*/
smp_mb();
if (atomic_read(&root->will_be_snapshotted)) {
btrfs_end_write_no_snapshotting(root);
return 0;
}
return 1;
}
void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
{
while (true) {
int ret;
ret = btrfs_start_write_no_snapshotting(root);
if (ret)
break;
wait_var_event(&root->will_be_snapshotted,
!atomic_read(&root->will_be_snapshotted));
}
}
void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
{
struct btrfs_fs_info *fs_info = bg->fs_info;
spin_lock(&fs_info->unused_bgs_lock);
if (list_empty(&bg->bg_list)) {
btrfs_get_block_group(bg);
trace_btrfs_add_unused_block_group(bg);
list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
}
spin_unlock(&fs_info->unused_bgs_lock);
}
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