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

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/*
* Copyright (C) 2008 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include "ctree.h"
#include "transaction.h"
#include "disk-io.h"
#include "locking.h"
#include "print-tree.h"
#include "compat.h"
#include "tree-log.h"
/* magic values for the inode_only field in btrfs_log_inode:
*
* LOG_INODE_ALL means to log everything
* LOG_INODE_EXISTS means to log just enough to recreate the inode
* during log replay
*/
#define LOG_INODE_ALL 0
#define LOG_INODE_EXISTS 1
/*
* directory trouble cases
*
* 1) on rename or unlink, if the inode being unlinked isn't in the fsync
* log, we must force a full commit before doing an fsync of the directory
* where the unlink was done.
* ---> record transid of last unlink/rename per directory
*
* mkdir foo/some_dir
* normal commit
* rename foo/some_dir foo2/some_dir
* mkdir foo/some_dir
* fsync foo/some_dir/some_file
*
* The fsync above will unlink the original some_dir without recording
* it in its new location (foo2). After a crash, some_dir will be gone
* unless the fsync of some_file forces a full commit
*
* 2) we must log any new names for any file or dir that is in the fsync
* log. ---> check inode while renaming/linking.
*
* 2a) we must log any new names for any file or dir during rename
* when the directory they are being removed from was logged.
* ---> check inode and old parent dir during rename
*
* 2a is actually the more important variant. With the extra logging
* a crash might unlink the old name without recreating the new one
*
* 3) after a crash, we must go through any directories with a link count
* of zero and redo the rm -rf
*
* mkdir f1/foo
* normal commit
* rm -rf f1/foo
* fsync(f1)
*
* The directory f1 was fully removed from the FS, but fsync was never
* called on f1, only its parent dir. After a crash the rm -rf must
* be replayed. This must be able to recurse down the entire
* directory tree. The inode link count fixup code takes care of the
* ugly details.
*/
/*
* stages for the tree walking. The first
* stage (0) is to only pin down the blocks we find
* the second stage (1) is to make sure that all the inodes
* we find in the log are created in the subvolume.
*
* The last stage is to deal with directories and links and extents
* and all the other fun semantics
*/
#define LOG_WALK_PIN_ONLY 0
#define LOG_WALK_REPLAY_INODES 1
#define LOG_WALK_REPLAY_ALL 2
static int btrfs_log_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
int inode_only);
static int link_to_fixup_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid);
static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_root *log,
struct btrfs_path *path,
u64 dirid, int del_all);
/*
* tree logging is a special write ahead log used to make sure that
* fsyncs and O_SYNCs can happen without doing full tree commits.
*
* Full tree commits are expensive because they require commonly
* modified blocks to be recowed, creating many dirty pages in the
* extent tree an 4x-6x higher write load than ext3.
*
* Instead of doing a tree commit on every fsync, we use the
* key ranges and transaction ids to find items for a given file or directory
* that have changed in this transaction. Those items are copied into
* a special tree (one per subvolume root), that tree is written to disk
* and then the fsync is considered complete.
*
* After a crash, items are copied out of the log-tree back into the
* subvolume tree. Any file data extents found are recorded in the extent
* allocation tree, and the log-tree freed.
*
* The log tree is read three times, once to pin down all the extents it is
* using in ram and once, once to create all the inodes logged in the tree
* and once to do all the other items.
*/
/*
* start a sub transaction and setup the log tree
* this increments the log tree writer count to make the people
* syncing the tree wait for us to finish
*/
static int start_log_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
int err = 0;
mutex_lock(&root->log_mutex);
if (root->log_root) {
if (!root->log_start_pid) {
root->log_start_pid = current->pid;
root->log_multiple_pids = false;
} else if (root->log_start_pid != current->pid) {
root->log_multiple_pids = true;
}
root->log_batch++;
atomic_inc(&root->log_writers);
mutex_unlock(&root->log_mutex);
return 0;
}
root->log_multiple_pids = false;
root->log_start_pid = current->pid;
mutex_lock(&root->fs_info->tree_log_mutex);
if (!root->fs_info->log_root_tree) {
ret = btrfs_init_log_root_tree(trans, root->fs_info);
if (ret)
err = ret;
}
if (err == 0 && !root->log_root) {
ret = btrfs_add_log_tree(trans, root);
if (ret)
err = ret;
}
mutex_unlock(&root->fs_info->tree_log_mutex);
root->log_batch++;
atomic_inc(&root->log_writers);
mutex_unlock(&root->log_mutex);
return err;
}
/*
* returns 0 if there was a log transaction running and we were able
* to join, or returns -ENOENT if there were not transactions
* in progress
*/
static int join_running_log_trans(struct btrfs_root *root)
{
int ret = -ENOENT;
smp_mb();
if (!root->log_root)
return -ENOENT;
mutex_lock(&root->log_mutex);
if (root->log_root) {
ret = 0;
atomic_inc(&root->log_writers);
}
mutex_unlock(&root->log_mutex);
return ret;
}
/*
* This either makes the current running log transaction wait
* until you call btrfs_end_log_trans() or it makes any future
* log transactions wait until you call btrfs_end_log_trans()
*/
int btrfs_pin_log_trans(struct btrfs_root *root)
{
int ret = -ENOENT;
mutex_lock(&root->log_mutex);
atomic_inc(&root->log_writers);
mutex_unlock(&root->log_mutex);
return ret;
}
/*
* indicate we're done making changes to the log tree
* and wake up anyone waiting to do a sync
*/
int btrfs_end_log_trans(struct btrfs_root *root)
{
if (atomic_dec_and_test(&root->log_writers)) {
smp_mb();
if (waitqueue_active(&root->log_writer_wait))
wake_up(&root->log_writer_wait);
}
return 0;
}
/*
* the walk control struct is used to pass state down the chain when
* processing the log tree. The stage field tells us which part
* of the log tree processing we are currently doing. The others
* are state fields used for that specific part
*/
struct walk_control {
/* should we free the extent on disk when done? This is used
* at transaction commit time while freeing a log tree
*/
int free;
/* should we write out the extent buffer? This is used
* while flushing the log tree to disk during a sync
*/
int write;
/* should we wait for the extent buffer io to finish? Also used
* while flushing the log tree to disk for a sync
*/
int wait;
/* pin only walk, we record which extents on disk belong to the
* log trees
*/
int pin;
/* what stage of the replay code we're currently in */
int stage;
/* the root we are currently replaying */
struct btrfs_root *replay_dest;
/* the trans handle for the current replay */
struct btrfs_trans_handle *trans;
/* the function that gets used to process blocks we find in the
* tree. Note the extent_buffer might not be up to date when it is
* passed in, and it must be checked or read if you need the data
* inside it
*/
int (*process_func)(struct btrfs_root *log, struct extent_buffer *eb,
struct walk_control *wc, u64 gen);
};
/*
* process_func used to pin down extents, write them or wait on them
*/
static int process_one_buffer(struct btrfs_root *log,
struct extent_buffer *eb,
struct walk_control *wc, u64 gen)
{
if (wc->pin)
btrfs_pin_extent(log->fs_info->extent_root,
eb->start, eb->len, 0);
if (btrfs_buffer_uptodate(eb, gen)) {
if (wc->write)
btrfs_write_tree_block(eb);
if (wc->wait)
btrfs_wait_tree_block_writeback(eb);
}
return 0;
}
/*
* Item overwrite used by replay and tree logging. eb, slot and key all refer
* to the src data we are copying out.
*
* root is the tree we are copying into, and path is a scratch
* path for use in this function (it should be released on entry and
* will be released on exit).
*
* If the key is already in the destination tree the existing item is
* overwritten. If the existing item isn't big enough, it is extended.
* If it is too large, it is truncated.
*
* If the key isn't in the destination yet, a new item is inserted.
*/
static noinline int overwrite_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct extent_buffer *eb, int slot,
struct btrfs_key *key)
{
int ret;
u32 item_size;
u64 saved_i_size = 0;
int save_old_i_size = 0;
unsigned long src_ptr;
unsigned long dst_ptr;
int overwrite_root = 0;
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
overwrite_root = 1;
item_size = btrfs_item_size_nr(eb, slot);
src_ptr = btrfs_item_ptr_offset(eb, slot);
/* look for the key in the destination tree */
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret == 0) {
char *src_copy;
char *dst_copy;
u32 dst_size = btrfs_item_size_nr(path->nodes[0],
path->slots[0]);
if (dst_size != item_size)
goto insert;
if (item_size == 0) {
btrfs_release_path(root, path);
return 0;
}
dst_copy = kmalloc(item_size, GFP_NOFS);
src_copy = kmalloc(item_size, GFP_NOFS);
if (!dst_copy || !src_copy) {
btrfs_release_path(root, path);
kfree(dst_copy);
kfree(src_copy);
return -ENOMEM;
}
read_extent_buffer(eb, src_copy, src_ptr, item_size);
dst_ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
read_extent_buffer(path->nodes[0], dst_copy, dst_ptr,
item_size);
ret = memcmp(dst_copy, src_copy, item_size);
kfree(dst_copy);
kfree(src_copy);
/*
* they have the same contents, just return, this saves
* us from cowing blocks in the destination tree and doing
* extra writes that may not have been done by a previous
* sync
*/
if (ret == 0) {
btrfs_release_path(root, path);
return 0;
}
}
insert:
btrfs_release_path(root, path);
/* try to insert the key into the destination tree */
ret = btrfs_insert_empty_item(trans, root, path,
key, item_size);
/* make sure any existing item is the correct size */
if (ret == -EEXIST) {
u32 found_size;
found_size = btrfs_item_size_nr(path->nodes[0],
path->slots[0]);
if (found_size > item_size) {
btrfs_truncate_item(trans, root, path, item_size, 1);
} else if (found_size < item_size) {
ret = btrfs_extend_item(trans, root, path,
item_size - found_size);
BUG_ON(ret);
}
} else if (ret) {
return ret;
}
dst_ptr = btrfs_item_ptr_offset(path->nodes[0],
path->slots[0]);
/* don't overwrite an existing inode if the generation number
* was logged as zero. This is done when the tree logging code
* is just logging an inode to make sure it exists after recovery.
*
* Also, don't overwrite i_size on directories during replay.
* log replay inserts and removes directory items based on the
* state of the tree found in the subvolume, and i_size is modified
* as it goes
*/
if (key->type == BTRFS_INODE_ITEM_KEY && ret == -EEXIST) {
struct btrfs_inode_item *src_item;
struct btrfs_inode_item *dst_item;
src_item = (struct btrfs_inode_item *)src_ptr;
dst_item = (struct btrfs_inode_item *)dst_ptr;
if (btrfs_inode_generation(eb, src_item) == 0)
goto no_copy;
if (overwrite_root &&
S_ISDIR(btrfs_inode_mode(eb, src_item)) &&
S_ISDIR(btrfs_inode_mode(path->nodes[0], dst_item))) {
save_old_i_size = 1;
saved_i_size = btrfs_inode_size(path->nodes[0],
dst_item);
}
}
copy_extent_buffer(path->nodes[0], eb, dst_ptr,
src_ptr, item_size);
if (save_old_i_size) {
struct btrfs_inode_item *dst_item;
dst_item = (struct btrfs_inode_item *)dst_ptr;
btrfs_set_inode_size(path->nodes[0], dst_item, saved_i_size);
}
/* make sure the generation is filled in */
if (key->type == BTRFS_INODE_ITEM_KEY) {
struct btrfs_inode_item *dst_item;
dst_item = (struct btrfs_inode_item *)dst_ptr;
if (btrfs_inode_generation(path->nodes[0], dst_item) == 0) {
btrfs_set_inode_generation(path->nodes[0], dst_item,
trans->transid);
}
}
no_copy:
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(root, path);
return 0;
}
/*
* simple helper to read an inode off the disk from a given root
* This can only be called for subvolume roots and not for the log
*/
static noinline struct inode *read_one_inode(struct btrfs_root *root,
u64 objectid)
{
struct btrfs_key key;
struct inode *inode;
key.objectid = objectid;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
if (IS_ERR(inode)) {
inode = NULL;
} else if (is_bad_inode(inode)) {
iput(inode);
inode = NULL;
}
return inode;
}
/* replays a single extent in 'eb' at 'slot' with 'key' into the
* subvolume 'root'. path is released on entry and should be released
* on exit.
*
* extents in the log tree have not been allocated out of the extent
* tree yet. So, this completes the allocation, taking a reference
* as required if the extent already exists or creating a new extent
* if it isn't in the extent allocation tree yet.
*
* The extent is inserted into the file, dropping any existing extents
* from the file that overlap the new one.
*/
static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct extent_buffer *eb, int slot,
struct btrfs_key *key)
{
int found_type;
u64 mask = root->sectorsize - 1;
u64 extent_end;
u64 alloc_hint;
u64 start = key->offset;
u64 saved_nbytes;
struct btrfs_file_extent_item *item;
struct inode *inode = NULL;
unsigned long size;
int ret = 0;
item = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(eb, item);
if (found_type == BTRFS_FILE_EXTENT_REG ||
found_type == BTRFS_FILE_EXTENT_PREALLOC)
extent_end = start + btrfs_file_extent_num_bytes(eb, item);
else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
size = btrfs_file_extent_inline_len(eb, item);
extent_end = (start + size + mask) & ~mask;
} else {
ret = 0;
goto out;
}
inode = read_one_inode(root, key->objectid);
if (!inode) {
ret = -EIO;
goto out;
}
/*
* first check to see if we already have this extent in the
* file. This must be done before the btrfs_drop_extents run
* so we don't try to drop this extent.
*/
ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
start, 0);
if (ret == 0 &&
(found_type == BTRFS_FILE_EXTENT_REG ||
found_type == BTRFS_FILE_EXTENT_PREALLOC)) {
struct btrfs_file_extent_item cmp1;
struct btrfs_file_extent_item cmp2;
struct btrfs_file_extent_item *existing;
struct extent_buffer *leaf;
leaf = path->nodes[0];
existing = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
read_extent_buffer(eb, &cmp1, (unsigned long)item,
sizeof(cmp1));
read_extent_buffer(leaf, &cmp2, (unsigned long)existing,
sizeof(cmp2));
/*
* we already have a pointer to this exact extent,
* we don't have to do anything
*/
if (memcmp(&cmp1, &cmp2, sizeof(cmp1)) == 0) {
btrfs_release_path(root, path);
goto out;
}
}
btrfs_release_path(root, path);
saved_nbytes = inode_get_bytes(inode);
/* drop any overlapping extents */
ret = btrfs_drop_extents(trans, inode, start, extent_end,
&alloc_hint, 1);
BUG_ON(ret);
if (found_type == BTRFS_FILE_EXTENT_REG ||
found_type == BTRFS_FILE_EXTENT_PREALLOC) {
u64 offset;
unsigned long dest_offset;
struct btrfs_key ins;
ret = btrfs_insert_empty_item(trans, root, path, key,
sizeof(*item));
BUG_ON(ret);
dest_offset = btrfs_item_ptr_offset(path->nodes[0],
path->slots[0]);
copy_extent_buffer(path->nodes[0], eb, dest_offset,
(unsigned long)item, sizeof(*item));
ins.objectid = btrfs_file_extent_disk_bytenr(eb, item);
ins.offset = btrfs_file_extent_disk_num_bytes(eb, item);
ins.type = BTRFS_EXTENT_ITEM_KEY;
offset = key->offset - btrfs_file_extent_offset(eb, item);
if (ins.objectid > 0) {
u64 csum_start;
u64 csum_end;
LIST_HEAD(ordered_sums);
/*
* is this extent already allocated in the extent
* allocation tree? If so, just add a reference
*/
ret = btrfs_lookup_extent(root, ins.objectid,
ins.offset);
if (ret == 0) {
ret = btrfs_inc_extent_ref(trans, root,
ins.objectid, ins.offset,
0, root->root_key.objectid,
key->objectid, offset);
} else {
/*
* insert the extent pointer in the extent
* allocation tree
*/
ret = btrfs_alloc_logged_file_extent(trans,
root, root->root_key.objectid,
key->objectid, offset, &ins);
BUG_ON(ret);
}
btrfs_release_path(root, path);
if (btrfs_file_extent_compression(eb, item)) {
csum_start = ins.objectid;
csum_end = csum_start + ins.offset;
} else {
csum_start = ins.objectid +
btrfs_file_extent_offset(eb, item);
csum_end = csum_start +
btrfs_file_extent_num_bytes(eb, item);
}
ret = btrfs_lookup_csums_range(root->log_root,
csum_start, csum_end - 1,
&ordered_sums);
BUG_ON(ret);
while (!list_empty(&ordered_sums)) {
struct btrfs_ordered_sum *sums;
sums = list_entry(ordered_sums.next,
struct btrfs_ordered_sum,
list);
ret = btrfs_csum_file_blocks(trans,
root->fs_info->csum_root,
sums);
BUG_ON(ret);
list_del(&sums->list);
kfree(sums);
}
} else {
btrfs_release_path(root, path);
}
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
/* inline extents are easy, we just overwrite them */
ret = overwrite_item(trans, root, path, eb, slot, key);
BUG_ON(ret);
}
inode_set_bytes(inode, saved_nbytes);
btrfs_update_inode(trans, root, inode);
out:
if (inode)
iput(inode);
return ret;
}
/*
* when cleaning up conflicts between the directory names in the
* subvolume, directory names in the log and directory names in the
* inode back references, we may have to unlink inodes from directories.
*
* This is a helper function to do the unlink of a specific directory
* item
*/
static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct inode *dir,
struct btrfs_dir_item *di)
{
struct inode *inode;
char *name;
int name_len;
struct extent_buffer *leaf;
struct btrfs_key location;
int ret;
leaf = path->nodes[0];
btrfs_dir_item_key_to_cpu(leaf, di, &location);
name_len = btrfs_dir_name_len(leaf, di);
name = kmalloc(name_len, GFP_NOFS);
if (!name)
return -ENOMEM;
read_extent_buffer(leaf, name, (unsigned long)(di + 1), name_len);
btrfs_release_path(root, path);
inode = read_one_inode(root, location.objectid);
BUG_ON(!inode);
ret = link_to_fixup_dir(trans, root, path, location.objectid);
BUG_ON(ret);
ret = btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
BUG_ON(ret);
kfree(name);
iput(inode);
return ret;
}
/*
* helper function to see if a given name and sequence number found
* in an inode back reference are already in a directory and correctly
* point to this inode
*/
static noinline int inode_in_dir(struct btrfs_root *root,
struct btrfs_path *path,
u64 dirid, u64 objectid, u64 index,
const char *name, int name_len)
{
struct btrfs_dir_item *di;
struct btrfs_key location;
int match = 0;
di = btrfs_lookup_dir_index_item(NULL, root, path, dirid,
index, name, name_len, 0);
if (di && !IS_ERR(di)) {
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
if (location.objectid != objectid)
goto out;
} else
goto out;
btrfs_release_path(root, path);
di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, name_len, 0);
if (di && !IS_ERR(di)) {
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
if (location.objectid != objectid)
goto out;
} else
goto out;
match = 1;
out:
btrfs_release_path(root, path);
return match;
}
/*
* helper function to check a log tree for a named back reference in
* an inode. This is used to decide if a back reference that is
* found in the subvolume conflicts with what we find in the log.
*
* inode backreferences may have multiple refs in a single item,
* during replay we process one reference at a time, and we don't
* want to delete valid links to a file from the subvolume if that
* link is also in the log.
*/
static noinline int backref_in_log(struct btrfs_root *log,
struct btrfs_key *key,
char *name, int namelen)
{
struct btrfs_path *path;
struct btrfs_inode_ref *ref;
unsigned long ptr;
unsigned long ptr_end;
unsigned long name_ptr;
int found_name_len;
int item_size;
int ret;
int match = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(NULL, log, key, path, 0, 0);
if (ret != 0)
goto out;
item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
ptr_end = ptr + item_size;
while (ptr < ptr_end) {
ref = (struct btrfs_inode_ref *)ptr;
found_name_len = btrfs_inode_ref_name_len(path->nodes[0], ref);
if (found_name_len == namelen) {
name_ptr = (unsigned long)(ref + 1);
ret = memcmp_extent_buffer(path->nodes[0], name,
name_ptr, namelen);
if (ret == 0) {
match = 1;
goto out;
}
}
ptr = (unsigned long)(ref + 1) + found_name_len;
}
out:
btrfs_free_path(path);
return match;
}
/*
* replay one inode back reference item found in the log tree.
* eb, slot and key refer to the buffer and key found in the log tree.
* root is the destination we are replaying into, and path is for temp
* use by this function. (it should be released on return).
*/
static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_root *log,
struct btrfs_path *path,
struct extent_buffer *eb, int slot,
struct btrfs_key *key)
{
struct inode *dir;
int ret;
struct btrfs_inode_ref *ref;
struct btrfs_dir_item *di;
struct inode *inode;
char *name;
int namelen;
unsigned long ref_ptr;
unsigned long ref_end;
/*
* it is possible that we didn't log all the parent directories
* for a given inode. If we don't find the dir, just don't
* copy the back ref in. The link count fixup code will take
* care of the rest
*/
dir = read_one_inode(root, key->offset);
if (!dir)
return -ENOENT;
inode = read_one_inode(root, key->objectid);
BUG_ON(!inode);
ref_ptr = btrfs_item_ptr_offset(eb, slot);
ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
again:
ref = (struct btrfs_inode_ref *)ref_ptr;
namelen = btrfs_inode_ref_name_len(eb, ref);
name = kmalloc(namelen, GFP_NOFS);
BUG_ON(!name);
read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
/* if we already have a perfect match, we're done */
if (inode_in_dir(root, path, dir->i_ino, inode->i_ino,
btrfs_inode_ref_index(eb, ref),
name, namelen)) {
goto out;
}
/*
* look for a conflicting back reference in the metadata.
* if we find one we have to unlink that name of the file
* before we add our new link. Later on, we overwrite any
* existing back reference, and we don't want to create
* dangling pointers in the directory.
*/
conflict_again:
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret == 0) {
char *victim_name;
int victim_name_len;
struct btrfs_inode_ref *victim_ref;
unsigned long ptr;
unsigned long ptr_end;
struct extent_buffer *leaf = path->nodes[0];
/* are we trying to overwrite a back ref for the root directory
* if so, just jump out, we're done
*/
if (key->objectid == key->offset)
goto out_nowrite;
/* check all the names in this back reference to see
* if they are in the log. if so, we allow them to stay
* otherwise they must be unlinked as a conflict
*/
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
ptr_end = ptr + btrfs_item_size_nr(leaf, path->slots[0]);
while (ptr < ptr_end) {
victim_ref = (struct btrfs_inode_ref *)ptr;
victim_name_len = btrfs_inode_ref_name_len(leaf,
victim_ref);
victim_name = kmalloc(victim_name_len, GFP_NOFS);
BUG_ON(!victim_name);
read_extent_buffer(leaf, victim_name,
(unsigned long)(victim_ref + 1),
victim_name_len);
if (!backref_in_log(log, key, victim_name,
victim_name_len)) {
btrfs_inc_nlink(inode);
btrfs_release_path(root, path);
ret = btrfs_unlink_inode(trans, root, dir,
inode, victim_name,
victim_name_len);
kfree(victim_name);
btrfs_release_path(root, path);
goto conflict_again;
}
kfree(victim_name);
ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
}
BUG_ON(ret);
}
btrfs_release_path(root, path);
/* look for a conflicting sequence number */
di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
btrfs_inode_ref_index(eb, ref),
name, namelen, 0);
if (di && !IS_ERR(di)) {
ret = drop_one_dir_item(trans, root, path, dir, di);
BUG_ON(ret);
}
btrfs_release_path(root, path);
/* look for a conflicting name */
di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
name, namelen, 0);
if (di && !IS_ERR(di)) {
ret = drop_one_dir_item(trans, root, path, dir, di);
BUG_ON(ret);
}
btrfs_release_path(root, path);
/* insert our name */
ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
btrfs_inode_ref_index(eb, ref));
BUG_ON(ret);
btrfs_update_inode(trans, root, inode);
out:
ref_ptr = (unsigned long)(ref + 1) + namelen;
kfree(name);
if (ref_ptr < ref_end)
goto again;
/* finally write the back reference in the inode */
ret = overwrite_item(trans, root, path, eb, slot, key);
BUG_ON(ret);
out_nowrite:
btrfs_release_path(root, path);
iput(dir);
iput(inode);
return 0;
}
static int insert_orphan_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 offset)
{
int ret;
ret = btrfs_find_orphan_item(root, offset);
if (ret > 0)
ret = btrfs_insert_orphan_item(trans, root, offset);
return ret;
}
/*
* There are a few corners where the link count of the file can't
* be properly maintained during replay. So, instead of adding
* lots of complexity to the log code, we just scan the backrefs
* for any file that has been through replay.
*
* The scan will update the link count on the inode to reflect the
* number of back refs found. If it goes down to zero, the iput
* will free the inode.
*/
static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
u64 nlink = 0;
unsigned long ptr;
unsigned long ptr_end;
int name_len;
key.objectid = inode->i_ino;
key.type = BTRFS_INODE_REF_KEY;
key.offset = (u64)-1;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while (1) {
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
break;
if (ret > 0) {
if (path->slots[0] == 0)
break;
path->slots[0]--;
}
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid != inode->i_ino ||
key.type != BTRFS_INODE_REF_KEY)
break;
ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
ptr_end = ptr + btrfs_item_size_nr(path->nodes[0],
path->slots[0]);
while (ptr < ptr_end) {
struct btrfs_inode_ref *ref;
ref = (struct btrfs_inode_ref *)ptr;
name_len = btrfs_inode_ref_name_len(path->nodes[0],
ref);
ptr = (unsigned long)(ref + 1) + name_len;
nlink++;
}
if (key.offset == 0)
break;
key.offset--;
btrfs_release_path(root, path);
}
btrfs_release_path(root, path);
if (nlink != inode->i_nlink) {
inode->i_nlink = nlink;
btrfs_update_inode(trans, root, inode);
}
BTRFS_I(inode)->index_cnt = (u64)-1;
if (inode->i_nlink == 0) {
if (S_ISDIR(inode->i_mode)) {
ret = replay_dir_deletes(trans, root, NULL, path,
inode->i_ino, 1);
BUG_ON(ret);
}
ret = insert_orphan_item(trans, root, inode->i_ino);
BUG_ON(ret);
}
btrfs_free_path(path);
return 0;
}
static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path)
{
int ret;
struct btrfs_key key;
struct inode *inode;
key.objectid = BTRFS_TREE_LOG_FIXUP_OBJECTID;
key.type = BTRFS_ORPHAN_ITEM_KEY;
key.offset = (u64)-1;
while (1) {
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
break;
if (ret == 1) {
if (path->slots[0] == 0)
break;
path->slots[0]--;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.objectid != BTRFS_TREE_LOG_FIXUP_OBJECTID ||
key.type != BTRFS_ORPHAN_ITEM_KEY)
break;
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
btrfs_release_path(root, path);
inode = read_one_inode(root, key.offset);
BUG_ON(!inode);
ret = fixup_inode_link_count(trans, root, inode);
BUG_ON(ret);
iput(inode);
/*
* fixup on a directory may create new entries,
* make sure we always look for the highset possible
* offset
*/
key.offset = (u64)-1;
}
btrfs_release_path(root, path);
return 0;
}
/*
* record a given inode in the fixup dir so we can check its link
* count when replay is done. The link count is incremented here
* so the inode won't go away until we check it
*/
static noinline int link_to_fixup_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid)
{
struct btrfs_key key;
int ret = 0;
struct inode *inode;
inode = read_one_inode(root, objectid);
BUG_ON(!inode);
key.objectid = BTRFS_TREE_LOG_FIXUP_OBJECTID;
btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
key.offset = objectid;
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
btrfs_release_path(root, path);
if (ret == 0) {
btrfs_inc_nlink(inode);
btrfs_update_inode(trans, root, inode);
} else if (ret == -EEXIST) {
ret = 0;
} else {
BUG();
}
iput(inode);
return ret;
}
/*
* when replaying the log for a directory, we only insert names
* for inodes that actually exist. This means an fsync on a directory
* does not implicitly fsync all the new files in it
*/
static noinline int insert_one_name(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u64 dirid, u64 index,
char *name, int name_len, u8 type,
struct btrfs_key *location)
{
struct inode *inode;
struct inode *dir;
int ret;
inode = read_one_inode(root, location->objectid);
if (!inode)
return -ENOENT;
dir = read_one_inode(root, dirid);
if (!dir) {
iput(inode);
return -EIO;
}
ret = btrfs_add_link(trans, dir, inode, name, name_len, 1, index);
/* FIXME, put inode into FIXUP list */
iput(inode);
iput(dir);
return ret;
}
/*
* take a single entry in a log directory item and replay it into
* the subvolume.
*
* if a conflicting item exists in the subdirectory already,
* the inode it points to is unlinked and put into the link count
* fix up tree.
*
* If a name from the log points to a file or directory that does
* not exist in the FS, it is skipped. fsyncs on directories
* do not force down inodes inside that directory, just changes to the
* names or unlinks in a directory.
*/
static noinline int replay_one_name(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct extent_buffer *eb,
struct btrfs_dir_item *di,
struct btrfs_key *key)
{
char *name;
int name_len;
struct btrfs_dir_item *dst_di;
struct btrfs_key found_key;
struct btrfs_key log_key;
struct inode *dir;
u8 log_type;
int exists;
int ret;
dir = read_one_inode(root, key->objectid);
BUG_ON(!dir);
name_len = btrfs_dir_name_len(eb, di);
name = kmalloc(name_len, GFP_NOFS);
if (!name)
return -ENOMEM;
log_type = btrfs_dir_type(eb, di);
read_extent_buffer(eb, name, (unsigned long)(di + 1),
name_len);
btrfs_dir_item_key_to_cpu(eb, di, &log_key);
exists = btrfs_lookup_inode(trans, root, path, &log_key, 0);
if (exists == 0)
exists = 1;
else
exists = 0;
btrfs_release_path(root, path);
if (key->type == BTRFS_DIR_ITEM_KEY) {
dst_di = btrfs_lookup_dir_item(trans, root, path, key->objectid,
name, name_len, 1);
} else if (key->type == BTRFS_DIR_INDEX_KEY) {
dst_di = btrfs_lookup_dir_index_item(trans, root, path,
key->objectid,
key->offset, name,
name_len, 1);
} else {
BUG();
}
if (!dst_di || IS_ERR(dst_di)) {
/* we need a sequence number to insert, so we only
* do inserts for the BTRFS_DIR_INDEX_KEY types
*/
if (key->type != BTRFS_DIR_INDEX_KEY)
goto out;
goto insert;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], dst_di, &found_key);
/* the existing item matches the logged item */
if (found_key.objectid == log_key.objectid &&
found_key.type == log_key.type &&
found_key.offset == log_key.offset &&
btrfs_dir_type(path->nodes[0], dst_di) == log_type) {
goto out;
}
/*
* don't drop the conflicting directory entry if the inode
* for the new entry doesn't exist
*/
if (!exists)
goto out;
ret = drop_one_dir_item(trans, root, path, dir, dst_di);
BUG_ON(ret);
if (key->type == BTRFS_DIR_INDEX_KEY)
goto insert;
out:
btrfs_release_path(root, path);
kfree(name);
iput(dir);
return 0;
insert:
btrfs_release_path(root, path);
ret = insert_one_name(trans, root, path, key->objectid, key->offset,
name, name_len, log_type, &log_key);
BUG_ON(ret && ret != -ENOENT);
goto out;
}
/*
* find all the names in a directory item and reconcile them into
* the subvolume. Only BTRFS_DIR_ITEM_KEY types will have more than
* one name in a directory item, but the same code gets used for
* both directory index types
*/
static noinline int replay_one_dir_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct extent_buffer *eb, int slot,
struct btrfs_key *key)
{
int ret;
u32 item_size = btrfs_item_size_nr(eb, slot);
struct btrfs_dir_item *di;
int name_len;
unsigned long ptr;
unsigned long ptr_end;
ptr = btrfs_item_ptr_offset(eb, slot);
ptr_end = ptr + item_size;
while (ptr < ptr_end) {
di = (struct btrfs_dir_item *)ptr;
name_len = btrfs_dir_name_len(eb, di);
ret = replay_one_name(trans, root, path, eb, di, key);
BUG_ON(ret);
ptr = (unsigned long)(di + 1);
ptr += name_len;
}
return 0;
}
/*
* directory replay has two parts. There are the standard directory
* items in the log copied from the subvolume, and range items
* created in the log while the subvolume was logged.
*
* The range items tell us which parts of the key space the log
* is authoritative for. During replay, if a key in the subvolume
* directory is in a logged range item, but not actually in the log
* that means it was deleted from the directory before the fsync
* and should be removed.
*/
static noinline int find_dir_range(struct btrfs_root *root,
struct btrfs_path *path,
u64 dirid, int key_type,
u64 *start_ret, u64 *end_ret)
{
struct btrfs_key key;
u64 found_end;
struct btrfs_dir_log_item *item;
int ret;
int nritems;
if (*start_ret == (u64)-1)
return 1;
key.objectid = dirid;
key.type = key_type;
key.offset = *start_ret;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0) {
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
}
if (ret != 0)
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.type != key_type || key.objectid != dirid) {
ret = 1;
goto next;
}
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_dir_log_item);
found_end = btrfs_dir_log_end(path->nodes[0], item);
if (*start_ret >= key.offset && *start_ret <= found_end) {
ret = 0;
*start_ret = key.offset;
*end_ret = found_end;
goto out;
}
ret = 1;
next:
/* check the next slot in the tree to see if it is a valid item */
nritems = btrfs_header_nritems(path->nodes[0]);
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret)
goto out;
} else {
path->slots[0]++;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.type != key_type || key.objectid != dirid) {
ret = 1;
goto out;
}
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_dir_log_item);
found_end = btrfs_dir_log_end(path->nodes[0], item);
*start_ret = key.offset;
*end_ret = found_end;
ret = 0;
out:
btrfs_release_path(root, path);
return ret;
}
/*
* this looks for a given directory item in the log. If the directory
* item is not in the log, the item is removed and the inode it points
* to is unlinked
*/
static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_root *log,
struct btrfs_path *path,
struct btrfs_path *log_path,
struct inode *dir,
struct btrfs_key *dir_key)
{
int ret;
struct extent_buffer *eb;
int slot;
u32 item_size;
struct btrfs_dir_item *di;
struct btrfs_dir_item *log_di;
int name_len;
unsigned long ptr;
unsigned long ptr_end;
char *name;
struct inode *inode;
struct btrfs_key location;
again:
eb = path->nodes[0];
slot = path->slots[0];
item_size = btrfs_item_size_nr(eb, slot);
ptr = btrfs_item_ptr_offset(eb, slot);
ptr_end = ptr + item_size;
while (ptr < ptr_end) {
di = (struct btrfs_dir_item *)ptr;
name_len = btrfs_dir_name_len(eb, di);
name = kmalloc(name_len, GFP_NOFS);
if (!name) {
ret = -ENOMEM;
goto out;
}
read_extent_buffer(eb, name, (unsigned long)(di + 1),
name_len);
log_di = NULL;
if (log && dir_key->type == BTRFS_DIR_ITEM_KEY) {
log_di = btrfs_lookup_dir_item(trans, log, log_path,
dir_key->objectid,
name, name_len, 0);
} else if (log && dir_key->type == BTRFS_DIR_INDEX_KEY) {
log_di = btrfs_lookup_dir_index_item(trans, log,
log_path,
dir_key->objectid,
dir_key->offset,
name, name_len, 0);
}
if (!log_di || IS_ERR(log_di)) {
btrfs_dir_item_key_to_cpu(eb, di, &location);
btrfs_release_path(root, path);
btrfs_release_path(log, log_path);
inode = read_one_inode(root, location.objectid);
BUG_ON(!inode);
ret = link_to_fixup_dir(trans, root,
path, location.objectid);
BUG_ON(ret);
btrfs_inc_nlink(inode);
ret = btrfs_unlink_inode(trans, root, dir, inode,
name, name_len);
BUG_ON(ret);
kfree(name);
iput(inode);
/* there might still be more names under this key
* check and repeat if required
*/
ret = btrfs_search_slot(NULL, root, dir_key, path,
0, 0);
if (ret == 0)
goto again;
ret = 0;
goto out;
}
btrfs_release_path(log, log_path);
kfree(name);
ptr = (unsigned long)(di + 1);
ptr += name_len;
}
ret = 0;
out:
btrfs_release_path(root, path);
btrfs_release_path(log, log_path);
return ret;
}
/*
* deletion replay happens before we copy any new directory items
* out of the log or out of backreferences from inodes. It
* scans the log to find ranges of keys that log is authoritative for,
* and then scans the directory to find items in those ranges that are
* not present in the log.
*
* Anything we don't find in the log is unlinked and removed from the
* directory.
*/
static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_root *log,
struct btrfs_path *path,
u64 dirid, int del_all)
{
u64 range_start;
u64 range_end;
int key_type = BTRFS_DIR_LOG_ITEM_KEY;
int ret = 0;
struct btrfs_key dir_key;
struct btrfs_key found_key;
struct btrfs_path *log_path;
struct inode *dir;
dir_key.objectid = dirid;
dir_key.type = BTRFS_DIR_ITEM_KEY;
log_path = btrfs_alloc_path();
if (!log_path)
return -ENOMEM;
dir = read_one_inode(root, dirid);
/* it isn't an error if the inode isn't there, that can happen
* because we replay the deletes before we copy in the inode item
* from the log
*/
if (!dir) {
btrfs_free_path(log_path);
return 0;
}
again:
range_start = 0;
range_end = 0;
while (1) {
if (del_all)
range_end = (u64)-1;
else {
ret = find_dir_range(log, path, dirid, key_type,
&range_start, &range_end);
if (ret != 0)
break;
}
dir_key.offset = range_start;
while (1) {
int nritems;
ret = btrfs_search_slot(NULL, root, &dir_key, path,
0, 0);
if (ret < 0)
goto out;
nritems = btrfs_header_nritems(path->nodes[0]);
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret)
break;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (found_key.objectid != dirid ||
found_key.type != dir_key.type)
goto next_type;
if (found_key.offset > range_end)
break;
ret = check_item_in_log(trans, root, log, path,
log_path, dir,
&found_key);
BUG_ON(ret);
if (found_key.offset == (u64)-1)
break;
dir_key.offset = found_key.offset + 1;
}
btrfs_release_path(root, path);
if (range_end == (u64)-1)
break;
range_start = range_end + 1;
}
next_type:
ret = 0;
if (key_type == BTRFS_DIR_LOG_ITEM_KEY) {
key_type = BTRFS_DIR_LOG_INDEX_KEY;
dir_key.type = BTRFS_DIR_INDEX_KEY;
btrfs_release_path(root, path);
goto again;
}
out:
btrfs_release_path(root, path);
btrfs_free_path(log_path);
iput(dir);
return ret;
}
/*
* the process_func used to replay items from the log tree. This
* gets called in two different stages. The first stage just looks
* for inodes and makes sure they are all copied into the subvolume.
*
* The second stage copies all the other item types from the log into
* the subvolume. The two stage approach is slower, but gets rid of
* lots of complexity around inodes referencing other inodes that exist
* only in the log (references come from either directory items or inode
* back refs).
*/
static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
struct walk_control *wc, u64 gen)
{
int nritems;
struct btrfs_path *path;
struct btrfs_root *root = wc->replay_dest;
struct btrfs_key key;
int level;
int i;
int ret;
btrfs_read_buffer(eb, gen);
level = btrfs_header_level(eb);
if (level != 0)
return 0;
path = btrfs_alloc_path();
BUG_ON(!path);
nritems = btrfs_header_nritems(eb);
for (i = 0; i < nritems; i++) {
btrfs_item_key_to_cpu(eb, &key, i);
/* inode keys are done during the first stage */
if (key.type == BTRFS_INODE_ITEM_KEY &&
wc->stage == LOG_WALK_REPLAY_INODES) {
struct btrfs_inode_item *inode_item;
u32 mode;
inode_item = btrfs_item_ptr(eb, i,
struct btrfs_inode_item);
mode = btrfs_inode_mode(eb, inode_item);
if (S_ISDIR(mode)) {
ret = replay_dir_deletes(wc->trans,
root, log, path, key.objectid, 0);
BUG_ON(ret);
}
ret = overwrite_item(wc->trans, root, path,
eb, i, &key);
BUG_ON(ret);
/* for regular files, make sure corresponding
* orhpan item exist. extents past the new EOF
* will be truncated later by orphan cleanup.
*/
if (S_ISREG(mode)) {
ret = insert_orphan_item(wc->trans, root,
key.objectid);
BUG_ON(ret);
}
ret = link_to_fixup_dir(wc->trans, root,
path, key.objectid);
BUG_ON(ret);
}
if (wc->stage < LOG_WALK_REPLAY_ALL)
continue;
/* these keys are simply copied */
if (key.type == BTRFS_XATTR_ITEM_KEY) {
ret = overwrite_item(wc->trans, root, path,
eb, i, &key);
BUG_ON(ret);
} else if (key.type == BTRFS_INODE_REF_KEY) {
ret = add_inode_ref(wc->trans, root, log, path,
eb, i, &key);
BUG_ON(ret && ret != -ENOENT);
} else if (key.type == BTRFS_EXTENT_DATA_KEY) {
ret = replay_one_extent(wc->trans, root, path,
eb, i, &key);
BUG_ON(ret);
} else if (key.type == BTRFS_DIR_ITEM_KEY ||
key.type == BTRFS_DIR_INDEX_KEY) {
ret = replay_one_dir_item(wc->trans, root, path,
eb, i, &key);
BUG_ON(ret);
}
}
btrfs_free_path(path);
return 0;
}
static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int *level,
struct walk_control *wc)
{
u64 root_owner;
u64 bytenr;
u64 ptr_gen;
struct extent_buffer *next;
struct extent_buffer *cur;
struct extent_buffer *parent;
u32 blocksize;
int ret = 0;
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
while (*level > 0) {
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
cur = path->nodes[*level];
if (btrfs_header_level(cur) != *level)
WARN_ON(1);
if (path->slots[*level] >=
btrfs_header_nritems(cur))
break;
bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
blocksize = btrfs_level_size(root, *level - 1);
parent = path->nodes[*level];
root_owner = btrfs_header_owner(parent);
next = btrfs_find_create_tree_block(root, bytenr, blocksize);
if (!next)
return -ENOMEM;
if (*level == 1) {
wc->process_func(root, next, wc, ptr_gen);
path->slots[*level]++;
if (wc->free) {
btrfs_read_buffer(next, ptr_gen);
btrfs_tree_lock(next);
clean_tree_block(trans, root, next);
btrfs_set_lock_blocking(next);
btrfs_wait_tree_block_writeback(next);
btrfs_tree_unlock(next);
WARN_ON(root_owner !=
BTRFS_TREE_LOG_OBJECTID);
ret = btrfs_free_reserved_extent(root,
bytenr, blocksize);
BUG_ON(ret);
}
free_extent_buffer(next);
continue;
}
btrfs_read_buffer(next, ptr_gen);
WARN_ON(*level <= 0);
if (path->nodes[*level-1])
free_extent_buffer(path->nodes[*level-1]);
path->nodes[*level-1] = next;
*level = btrfs_header_level(next);
path->slots[*level] = 0;
cond_resched();
}
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
path->slots[*level] = btrfs_header_nritems(path->nodes[*level]);
cond_resched();
return 0;
}
static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int *level,
struct walk_control *wc)
{
u64 root_owner;
int i;
int slot;
int ret;
for (i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
slot = path->slots[i];
if (slot + 1 < btrfs_header_nritems(path->nodes[i])) {
path->slots[i]++;
*level = i;
WARN_ON(*level == 0);
return 0;
} else {
struct extent_buffer *parent;
if (path->nodes[*level] == root->node)
parent = path->nodes[*level];
else
parent = path->nodes[*level + 1];
root_owner = btrfs_header_owner(parent);
wc->process_func(root, path->nodes[*level], wc,
btrfs_header_generation(path->nodes[*level]));
if (wc->free) {
struct extent_buffer *next;
next = path->nodes[*level];
btrfs_tree_lock(next);
clean_tree_block(trans, root, next);
btrfs_set_lock_blocking(next);
btrfs_wait_tree_block_writeback(next);
btrfs_tree_unlock(next);
WARN_ON(root_owner != BTRFS_TREE_LOG_OBJECTID);
ret = btrfs_free_reserved_extent(root,
path->nodes[*level]->start,
path->nodes[*level]->len);
BUG_ON(ret);
}
free_extent_buffer(path->nodes[*level]);
path->nodes[*level] = NULL;
*level = i + 1;
}
}
return 1;
}
/*
* drop the reference count on the tree rooted at 'snap'. This traverses
* the tree freeing any blocks that have a ref count of zero after being
* decremented.
*/
static int walk_log_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *log, struct walk_control *wc)
{
int ret = 0;
int wret;
int level;
struct btrfs_path *path;
int i;
int orig_level;
path = btrfs_alloc_path();
BUG_ON(!path);
level = btrfs_header_level(log->node);
orig_level = level;
path->nodes[level] = log->node;
extent_buffer_get(log->node);
path->slots[level] = 0;
while (1) {
wret = walk_down_log_tree(trans, log, path, &level, wc);
if (wret > 0)
break;
if (wret < 0)
ret = wret;
wret = walk_up_log_tree(trans, log, path, &level, wc);
if (wret > 0)
break;
if (wret < 0)
ret = wret;
}
/* was the root node processed? if not, catch it here */
if (path->nodes[orig_level]) {
wc->process_func(log, path->nodes[orig_level], wc,
btrfs_header_generation(path->nodes[orig_level]));
if (wc->free) {
struct extent_buffer *next;
next = path->nodes[orig_level];
btrfs_tree_lock(next);
clean_tree_block(trans, log, next);
btrfs_set_lock_blocking(next);
btrfs_wait_tree_block_writeback(next);
btrfs_tree_unlock(next);
WARN_ON(log->root_key.objectid !=
BTRFS_TREE_LOG_OBJECTID);
ret = btrfs_free_reserved_extent(log, next->start,
next->len);
BUG_ON(ret);
}
}
for (i = 0; i <= orig_level; i++) {
if (path->nodes[i]) {
free_extent_buffer(path->nodes[i]);
path->nodes[i] = NULL;
}
}
btrfs_free_path(path);
return ret;
}
/*
* helper function to update the item for a given subvolumes log root
* in the tree of log roots
*/
static int update_log_root(struct btrfs_trans_handle *trans,
struct btrfs_root *log)
{
int ret;
if (log->log_transid == 1) {
/* insert root item on the first sync */
ret = btrfs_insert_root(trans, log->fs_info->log_root_tree,
&log->root_key, &log->root_item);
} else {
ret = btrfs_update_root(trans, log->fs_info->log_root_tree,
&log->root_key, &log->root_item);
}
return ret;
}
static int wait_log_commit(struct btrfs_trans_handle *trans,
struct btrfs_root *root, unsigned long transid)
{
DEFINE_WAIT(wait);
int index = transid % 2;
/*
* we only allow two pending log transactions at a time,
* so we know that if ours is more than 2 older than the
* current transaction, we're done
*/
do {
prepare_to_wait(&root->log_commit_wait[index],
&wait, TASK_UNINTERRUPTIBLE);
mutex_unlock(&root->log_mutex);
if (root->fs_info->last_trans_log_full_commit !=
trans->transid && root->log_transid < transid + 2 &&
atomic_read(&root->log_commit[index]))
schedule();
finish_wait(&root->log_commit_wait[index], &wait);
mutex_lock(&root->log_mutex);
} while (root->log_transid < transid + 2 &&
atomic_read(&root->log_commit[index]));
return 0;
}
static int wait_for_writer(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
DEFINE_WAIT(wait);
while (atomic_read(&root->log_writers)) {
prepare_to_wait(&root->log_writer_wait,
&wait, TASK_UNINTERRUPTIBLE);
mutex_unlock(&root->log_mutex);
if (root->fs_info->last_trans_log_full_commit !=
trans->transid && atomic_read(&root->log_writers))
schedule();
mutex_lock(&root->log_mutex);
finish_wait(&root->log_writer_wait, &wait);
}
return 0;
}
/*
* btrfs_sync_log does sends a given tree log down to the disk and
* updates the super blocks to record it. When this call is done,
* you know that any inodes previously logged are safely on disk only
* if it returns 0.
*
* Any other return value means you need to call btrfs_commit_transaction.
* Some of the edge cases for fsyncing directories that have had unlinks
* or renames done in the past mean that sometimes the only safe
* fsync is to commit the whole FS. When btrfs_sync_log returns -EAGAIN,
* that has happened.
*/
int btrfs_sync_log(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int index1;
int index2;
int mark;
int ret;
struct btrfs_root *log = root->log_root;
struct btrfs_root *log_root_tree = root->fs_info->log_root_tree;
unsigned long log_transid = 0;
mutex_lock(&root->log_mutex);
index1 = root->log_transid % 2;
if (atomic_read(&root->log_commit[index1])) {
wait_log_commit(trans, root, root->log_transid);
mutex_unlock(&root->log_mutex);
return 0;
}
atomic_set(&root->log_commit[index1], 1);
/* wait for previous tree log sync to complete */
if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
wait_log_commit(trans, root, root->log_transid - 1);
while (1) {
unsigned long batch = root->log_batch;
if (root->log_multiple_pids) {
mutex_unlock(&root->log_mutex);
schedule_timeout_uninterruptible(1);
mutex_lock(&root->log_mutex);
}
wait_for_writer(trans, root);
if (batch == root->log_batch)
break;
}
/* bail out if we need to do a full commit */
if (root->fs_info->last_trans_log_full_commit == trans->transid) {
ret = -EAGAIN;
mutex_unlock(&root->log_mutex);
goto out;
}
log_transid = root->log_transid;
if (log_transid % 2 == 0)
mark = EXTENT_DIRTY;
else
mark = EXTENT_NEW;
/* we start IO on all the marked extents here, but we don't actually
* wait for them until later.
*/
ret = btrfs_write_marked_extents(log, &log->dirty_log_pages, mark);
BUG_ON(ret);
btrfs_set_root_node(&log->root_item, log->node);
root->log_batch = 0;
root->log_transid++;
log->log_transid = root->log_transid;
root->log_start_pid = 0;
smp_mb();
/*
* IO has been started, blocks of the log tree have WRITTEN flag set
* in their headers. new modifications of the log will be written to
* new positions. so it's safe to allow log writers to go in.
*/
mutex_unlock(&root->log_mutex);
mutex_lock(&log_root_tree->log_mutex);
log_root_tree->log_batch++;
atomic_inc(&log_root_tree->log_writers);
mutex_unlock(&log_root_tree->log_mutex);
ret = update_log_root(trans, log);
mutex_lock(&log_root_tree->log_mutex);
if (atomic_dec_and_test(&log_root_tree->log_writers)) {
smp_mb();
if (waitqueue_active(&log_root_tree->log_writer_wait))
wake_up(&log_root_tree->log_writer_wait);
}
if (ret) {
BUG_ON(ret != -ENOSPC);
root->fs_info->last_trans_log_full_commit = trans->transid;
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
mutex_unlock(&log_root_tree->log_mutex);
ret = -EAGAIN;
goto out;
}
index2 = log_root_tree->log_transid % 2;
if (atomic_read(&log_root_tree->log_commit[index2])) {
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
wait_log_commit(trans, log_root_tree,
log_root_tree->log_transid);
mutex_unlock(&log_root_tree->log_mutex);
ret = 0;
goto out;
}
atomic_set(&log_root_tree->log_commit[index2], 1);
if (atomic_read(&log_root_tree->log_commit[(index2 + 1) % 2])) {
wait_log_commit(trans, log_root_tree,
log_root_tree->log_transid - 1);
}
wait_for_writer(trans, log_root_tree);
/*
* now that we've moved on to the tree of log tree roots,
* check the full commit flag again
*/
if (root->fs_info->last_trans_log_full_commit == trans->transid) {
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
mutex_unlock(&log_root_tree->log_mutex);
ret = -EAGAIN;
goto out_wake_log_root;
}
ret = btrfs_write_and_wait_marked_extents(log_root_tree,
&log_root_tree->dirty_log_pages,
EXTENT_DIRTY | EXTENT_NEW);
BUG_ON(ret);
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
btrfs_set_super_log_root(&root->fs_info->super_for_commit,
log_root_tree->node->start);
btrfs_set_super_log_root_level(&root->fs_info->super_for_commit,
btrfs_header_level(log_root_tree->node));
log_root_tree->log_batch = 0;
log_root_tree->log_transid++;
smp_mb();
mutex_unlock(&log_root_tree->log_mutex);
/*
* nobody else is going to jump in and write the the ctree
* super here because the log_commit atomic below is protecting
* us. We must be called with a transaction handle pinning
* the running transaction open, so a full commit can't hop
* in and cause problems either.
*/
write_ctree_super(trans, root->fs_info->tree_root, 1);
ret = 0;
mutex_lock(&root->log_mutex);
if (root->last_log_commit < log_transid)
root->last_log_commit = log_transid;
mutex_unlock(&root->log_mutex);
out_wake_log_root:
atomic_set(&log_root_tree->log_commit[index2], 0);
smp_mb();
if (waitqueue_active(&log_root_tree->log_commit_wait[index2]))
wake_up(&log_root_tree->log_commit_wait[index2]);
out:
atomic_set(&root->log_commit[index1], 0);
smp_mb();
if (waitqueue_active(&root->log_commit_wait[index1]))
wake_up(&root->log_commit_wait[index1]);
return ret;
}
static void free_log_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *log)
{
int ret;
u64 start;
u64 end;
struct walk_control wc = {
.free = 1,
.process_func = process_one_buffer
};
ret = walk_log_tree(trans, log, &wc);
BUG_ON(ret);
while (1) {
ret = find_first_extent_bit(&log->dirty_log_pages,
0, &start, &end, EXTENT_DIRTY | EXTENT_NEW);
if (ret)
break;
clear_extent_bits(&log->dirty_log_pages, start, end,
EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);
}
free_extent_buffer(log->node);
kfree(log);
}
/*
* free all the extents used by the tree log. This should be called
* at commit time of the full transaction
*/
int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root)
{
if (root->log_root) {
free_log_tree(trans, root->log_root);
root->log_root = NULL;
}
return 0;
}
int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info)
{
if (fs_info->log_root_tree) {
free_log_tree(trans, fs_info->log_root_tree);
fs_info->log_root_tree = NULL;
}
return 0;
}
/*
* If both a file and directory are logged, and unlinks or renames are
* mixed in, we have a few interesting corners:
*
* create file X in dir Y
* link file X to X.link in dir Y
* fsync file X
* unlink file X but leave X.link
* fsync dir Y
*
* After a crash we would expect only X.link to exist. But file X
* didn't get fsync'd again so the log has back refs for X and X.link.
*
* We solve this by removing directory entries and inode backrefs from the
* log when a file that was logged in the current transaction is
* unlinked. Any later fsync will include the updated log entries, and
* we'll be able to reconstruct the proper directory items from backrefs.
*
* This optimizations allows us to avoid relogging the entire inode
* or the entire directory.
*/
int btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
struct inode *dir, u64 index)
{
struct btrfs_root *log;
struct btrfs_dir_item *di;
struct btrfs_path *path;
int ret;
int err = 0;
int bytes_del = 0;
if (BTRFS_I(dir)->logged_trans < trans->transid)
return 0;
ret = join_running_log_trans(root);
if (ret)
return 0;
mutex_lock(&BTRFS_I(dir)->log_mutex);
log = root->log_root;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
di = btrfs_lookup_dir_item(trans, log, path, dir->i_ino,
name, name_len, -1);
if (IS_ERR(di)) {
err = PTR_ERR(di);
goto fail;
}
if (di) {
ret = btrfs_delete_one_dir_name(trans, log, path, di);
bytes_del += name_len;
BUG_ON(ret);
}
btrfs_release_path(log, path);
di = btrfs_lookup_dir_index_item(trans, log, path, dir->i_ino,
index, name, name_len, -1);
if (IS_ERR(di)) {
err = PTR_ERR(di);
goto fail;
}
if (di) {
ret = btrfs_delete_one_dir_name(trans, log, path, di);
bytes_del += name_len;
BUG_ON(ret);
}
/* update the directory size in the log to reflect the names
* we have removed
*/
if (bytes_del) {
struct btrfs_key key;
key.objectid = dir->i_ino;
key.offset = 0;
key.type = BTRFS_INODE_ITEM_KEY;
btrfs_release_path(log, path);
ret = btrfs_search_slot(trans, log, &key, path, 0, 1);
if (ret < 0) {
err = ret;
goto fail;
}
if (ret == 0) {
struct btrfs_inode_item *item;
u64 i_size;
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
i_size = btrfs_inode_size(path->nodes[0], item);
if (i_size > bytes_del)
i_size -= bytes_del;
else
i_size = 0;
btrfs_set_inode_size(path->nodes[0], item, i_size);
btrfs_mark_buffer_dirty(path->nodes[0]);
} else
ret = 0;
btrfs_release_path(log, path);
}
fail:
btrfs_free_path(path);
mutex_unlock(&BTRFS_I(dir)->log_mutex);
if (ret == -ENOSPC) {
root->fs_info->last_trans_log_full_commit = trans->transid;
ret = 0;
}
btrfs_end_log_trans(root);
return err;
}
/* see comments for btrfs_del_dir_entries_in_log */
int btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
struct inode *inode, u64 dirid)
{
struct btrfs_root *log;
u64 index;
int ret;
if (BTRFS_I(inode)->logged_trans < trans->transid)
return 0;
ret = join_running_log_trans(root);
if (ret)
return 0;
log = root->log_root;
mutex_lock(&BTRFS_I(inode)->log_mutex);
ret = btrfs_del_inode_ref(trans, log, name, name_len, inode->i_ino,
dirid, &index);
mutex_unlock(&BTRFS_I(inode)->log_mutex);
if (ret == -ENOSPC) {
root->fs_info->last_trans_log_full_commit = trans->transid;
ret = 0;
}
btrfs_end_log_trans(root);
return ret;
}
/*
* creates a range item in the log for 'dirid'. first_offset and
* last_offset tell us which parts of the key space the log should
* be considered authoritative for.
*/
static noinline int insert_dir_log_key(struct btrfs_trans_handle *trans,
struct btrfs_root *log,
struct btrfs_path *path,
int key_type, u64 dirid,
u64 first_offset, u64 last_offset)
{
int ret;
struct btrfs_key key;
struct btrfs_dir_log_item *item;
key.objectid = dirid;
key.offset = first_offset;
if (key_type == BTRFS_DIR_ITEM_KEY)
key.type = BTRFS_DIR_LOG_ITEM_KEY;
else
key.type = BTRFS_DIR_LOG_INDEX_KEY;
ret = btrfs_insert_empty_item(trans, log, path, &key, sizeof(*item));
if (ret)
return ret;
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_dir_log_item);
btrfs_set_dir_log_end(path->nodes[0], item, last_offset);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(log, path);
return 0;
}
/*
* log all the items included in the current transaction for a given
* directory. This also creates the range items in the log tree required
* to replay anything deleted before the fsync
*/
static noinline int log_dir_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
struct btrfs_path *path,
struct btrfs_path *dst_path, int key_type,
u64 min_offset, u64 *last_offset_ret)
{
struct btrfs_key min_key;
struct btrfs_key max_key;
struct btrfs_root *log = root->log_root;
struct extent_buffer *src;
int err = 0;
int ret;
int i;
int nritems;
u64 first_offset = min_offset;
u64 last_offset = (u64)-1;
log = root->log_root;
max_key.objectid = inode->i_ino;
max_key.offset = (u64)-1;
max_key.type = key_type;
min_key.objectid = inode->i_ino;
min_key.type = key_type;
min_key.offset = min_offset;
path->keep_locks = 1;
ret = btrfs_search_forward(root, &min_key, &max_key,
path, 0, trans->transid);
/*
* we didn't find anything from this transaction, see if there
* is anything at all
*/
if (ret != 0 || min_key.objectid != inode->i_ino ||
min_key.type != key_type) {
min_key.objectid = inode->i_ino;
min_key.type = key_type;
min_key.offset = (u64)-1;
btrfs_release_path(root, path);
ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
if (ret < 0) {
btrfs_release_path(root, path);
return ret;
}
ret = btrfs_previous_item(root, path, inode->i_ino, key_type);
/* if ret == 0 there are items for this type,
* create a range to tell us the last key of this type.
* otherwise, there are no items in this directory after
* *min_offset, and we create a range to indicate that.
*/
if (ret == 0) {
struct btrfs_key tmp;
btrfs_item_key_to_cpu(path->nodes[0], &tmp,
path->slots[0]);
if (key_type == tmp.type)
first_offset = max(min_offset, tmp.offset) + 1;
}
goto done;
}
/* go backward to find any previous key */
ret = btrfs_previous_item(root, path, inode->i_ino, key_type);
if (ret == 0) {
struct btrfs_key tmp;
btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]);
if (key_type == tmp.type) {
first_offset = tmp.offset;
ret = overwrite_item(trans, log, dst_path,
path->nodes[0], path->slots[0],
&tmp);
if (ret) {
err = ret;
goto done;
}
}
}
btrfs_release_path(root, path);
/* find the first key from this transaction again */
ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
if (ret != 0) {
WARN_ON(1);
goto done;
}
/*
* we have a block from this transaction, log every item in it
* from our directory
*/
while (1) {
struct btrfs_key tmp;
src = path->nodes[0];
nritems = btrfs_header_nritems(src);
for (i = path->slots[0]; i < nritems; i++) {
btrfs_item_key_to_cpu(src, &min_key, i);
if (min_key.objectid != inode->i_ino ||
min_key.type != key_type)
goto done;
ret = overwrite_item(trans, log, dst_path, src, i,
&min_key);
if (ret) {
err = ret;
goto done;
}
}
path->slots[0] = nritems;
/*
* look ahead to the next item and see if it is also
* from this directory and from this transaction
*/
ret = btrfs_next_leaf(root, path);
if (ret == 1) {
last_offset = (u64)-1;
goto done;
}
btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]);
if (tmp.objectid != inode->i_ino || tmp.type != key_type) {
last_offset = (u64)-1;
goto done;
}
if (btrfs_header_generation(path->nodes[0]) != trans->transid) {
ret = overwrite_item(trans, log, dst_path,
path->nodes[0], path->slots[0],
&tmp);
if (ret)
err = ret;
else
last_offset = tmp.offset;
goto done;
}
}
done:
btrfs_release_path(root, path);
btrfs_release_path(log, dst_path);
if (err == 0) {
*last_offset_ret = last_offset;
/*
* insert the log range keys to indicate where the log
* is valid
*/
ret = insert_dir_log_key(trans, log, path, key_type,
inode->i_ino, first_offset,
last_offset);
if (ret)
err = ret;
}
return err;
}
/*
* logging directories is very similar to logging inodes, We find all the items
* from the current transaction and write them to the log.
*
* The recovery code scans the directory in the subvolume, and if it finds a
* key in the range logged that is not present in the log tree, then it means
* that dir entry was unlinked during the transaction.
*
* In order for that scan to work, we must include one key smaller than
* the smallest logged by this transaction and one key larger than the largest
* key logged by this transaction.
*/
static noinline int log_directory_changes(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
struct btrfs_path *path,
struct btrfs_path *dst_path)
{
u64 min_key;
u64 max_key;
int ret;
int key_type = BTRFS_DIR_ITEM_KEY;
again:
min_key = 0;
max_key = 0;
while (1) {
ret = log_dir_items(trans, root, inode, path,
dst_path, key_type, min_key,
&max_key);
if (ret)
return ret;
if (max_key == (u64)-1)
break;
min_key = max_key + 1;
}
if (key_type == BTRFS_DIR_ITEM_KEY) {
key_type = BTRFS_DIR_INDEX_KEY;
goto again;
}
return 0;
}
/*
* a helper function to drop items from the log before we relog an
* inode. max_key_type indicates the highest item type to remove.
* This cannot be run for file data extents because it does not
* free the extents they point to.
*/
static int drop_objectid_items(struct btrfs_trans_handle *trans,
struct btrfs_root *log,
struct btrfs_path *path,
u64 objectid, int max_key_type)
{
int ret;
struct btrfs_key key;
struct btrfs_key found_key;
key.objectid = objectid;
key.type = max_key_type;
key.offset = (u64)-1;
while (1) {
ret = btrfs_search_slot(trans, log, &key, path, -1, 1);
BUG_ON(ret == 0);
if (ret < 0)
break;
if (path->slots[0] == 0)
break;
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (found_key.objectid != objectid)
break;
ret = btrfs_del_item(trans, log, path);
BUG_ON(ret);
btrfs_release_path(log, path);
}
btrfs_release_path(log, path);
return ret;
}
static noinline int copy_items(struct btrfs_trans_handle *trans,
struct btrfs_root *log,
struct btrfs_path *dst_path,
struct extent_buffer *src,
int start_slot, int nr, int inode_only)
{
unsigned long src_offset;
unsigned long dst_offset;
struct btrfs_file_extent_item *extent;
struct btrfs_inode_item *inode_item;
int ret;
struct btrfs_key *ins_keys;
u32 *ins_sizes;
char *ins_data;
int i;
struct list_head ordered_sums;
INIT_LIST_HEAD(&ordered_sums);
ins_data = kmalloc(nr * sizeof(struct btrfs_key) +
nr * sizeof(u32), GFP_NOFS);
if (!ins_data)
return -ENOMEM;
ins_sizes = (u32 *)ins_data;
ins_keys = (struct btrfs_key *)(ins_data + nr * sizeof(u32));
for (i = 0; i < nr; i++) {
ins_sizes[i] = btrfs_item_size_nr(src, i + start_slot);
btrfs_item_key_to_cpu(src, ins_keys + i, i + start_slot);
}
ret = btrfs_insert_empty_items(trans, log, dst_path,
ins_keys, ins_sizes, nr);
if (ret) {
kfree(ins_data);
return ret;
}
for (i = 0; i < nr; i++, dst_path->slots[0]++) {
dst_offset = btrfs_item_ptr_offset(dst_path->nodes[0],
dst_path->slots[0]);
src_offset = btrfs_item_ptr_offset(src, start_slot + i);
copy_extent_buffer(dst_path->nodes[0], src, dst_offset,
src_offset, ins_sizes[i]);
if (inode_only == LOG_INODE_EXISTS &&
ins_keys[i].type == BTRFS_INODE_ITEM_KEY) {
inode_item = btrfs_item_ptr(dst_path->nodes[0],
dst_path->slots[0],
struct btrfs_inode_item);
btrfs_set_inode_size(dst_path->nodes[0], inode_item, 0);
/* set the generation to zero so the recover code
* can tell the difference between an logging
* just to say 'this inode exists' and a logging
* to say 'update this inode with these values'
*/
btrfs_set_inode_generation(dst_path->nodes[0],
inode_item, 0);
}
/* take a reference on file data extents so that truncates
* or deletes of this inode don't have to relog the inode
* again
*/
if (btrfs_key_type(ins_keys + i) == BTRFS_EXTENT_DATA_KEY) {
int found_type;
extent = btrfs_item_ptr(src, start_slot + i,
struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(src, extent);
if (found_type == BTRFS_FILE_EXTENT_REG ||
found_type == BTRFS_FILE_EXTENT_PREALLOC) {
u64 ds, dl, cs, cl;
ds = btrfs_file_extent_disk_bytenr(src,
extent);
/* ds == 0 is a hole */
if (ds == 0)
continue;
dl = btrfs_file_extent_disk_num_bytes(src,
extent);
cs = btrfs_file_extent_offset(src, extent);
cl = btrfs_file_extent_num_bytes(src,
extent);
if (btrfs_file_extent_compression(src,
extent)) {
cs = 0;
cl = dl;
}
ret = btrfs_lookup_csums_range(
log->fs_info->csum_root,
ds + cs, ds + cs + cl - 1,
&ordered_sums);
BUG_ON(ret);
}
}
}
btrfs_mark_buffer_dirty(dst_path->nodes[0]);
btrfs_release_path(log, dst_path);
kfree(ins_data);
/*
* we have to do this after the loop above to avoid changing the
* log tree while trying to change the log tree.
*/
ret = 0;
while (!list_empty(&ordered_sums)) {
struct btrfs_ordered_sum *sums = list_entry(ordered_sums.next,
struct btrfs_ordered_sum,
list);
if (!ret)
ret = btrfs_csum_file_blocks(trans, log, sums);
list_del(&sums->list);
kfree(sums);
}
return ret;
}
/* log a single inode in the tree log.
* At least one parent directory for this inode must exist in the tree
* or be logged already.
*
* Any items from this inode changed by the current transaction are copied
* to the log tree. An extra reference is taken on any extents in this
* file, allowing us to avoid a whole pile of corner cases around logging
* blocks that have been removed from the tree.
*
* See LOG_INODE_ALL and related defines for a description of what inode_only
* does.
*
* This handles both files and directories.
*/
static int btrfs_log_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
int inode_only)
{
struct btrfs_path *path;
struct btrfs_path *dst_path;
struct btrfs_key min_key;
struct btrfs_key max_key;
struct btrfs_root *log = root->log_root;
struct extent_buffer *src = NULL;
int err = 0;
int ret;
int nritems;
int ins_start_slot = 0;
int ins_nr;
log = root->log_root;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
dst_path = btrfs_alloc_path();
if (!dst_path) {
btrfs_free_path(path);
return -ENOMEM;
}
min_key.objectid = inode->i_ino;
min_key.type = BTRFS_INODE_ITEM_KEY;
min_key.offset = 0;
max_key.objectid = inode->i_ino;
/* today the code can only do partial logging of directories */
if (!S_ISDIR(inode->i_mode))
inode_only = LOG_INODE_ALL;
if (inode_only == LOG_INODE_EXISTS || S_ISDIR(inode->i_mode))
max_key.type = BTRFS_XATTR_ITEM_KEY;
else
max_key.type = (u8)-1;
max_key.offset = (u64)-1;
mutex_lock(&BTRFS_I(inode)->log_mutex);
/*
* a brute force approach to making sure we get the most uptodate
* copies of everything.
*/
if (S_ISDIR(inode->i_mode)) {
int max_key_type = BTRFS_DIR_LOG_INDEX_KEY;
if (inode_only == LOG_INODE_EXISTS)
max_key_type = BTRFS_XATTR_ITEM_KEY;
ret = drop_objectid_items(trans, log, path,
inode->i_ino, max_key_type);
} else {
ret = btrfs_truncate_inode_items(trans, log, inode, 0, 0);
}
if (ret) {
err = ret;
goto out_unlock;
}
path->keep_locks = 1;
while (1) {
ins_nr = 0;
ret = btrfs_search_forward(root, &min_key, &max_key,
path, 0, trans->transid);
if (ret != 0)
break;
again:
/* note, ins_nr might be > 0 here, cleanup outside the loop */
if (min_key.objectid != inode->i_ino)
break;
if (min_key.type > max_key.type)
break;
src = path->nodes[0];
if (ins_nr && ins_start_slot + ins_nr == path->slots[0]) {
ins_nr++;
goto next_slot;
} else if (!ins_nr) {
ins_start_slot = path->slots[0];
ins_nr = 1;
goto next_slot;
}
ret = copy_items(trans, log, dst_path, src, ins_start_slot,
ins_nr, inode_only);
if (ret) {
err = ret;
goto out_unlock;
}
ins_nr = 1;
ins_start_slot = path->slots[0];
next_slot:
nritems = btrfs_header_nritems(path->nodes[0]);
path->slots[0]++;
if (path->slots[0] < nritems) {
btrfs_item_key_to_cpu(path->nodes[0], &min_key,
path->slots[0]);
goto again;
}
if (ins_nr) {
ret = copy_items(trans, log, dst_path, src,
ins_start_slot,
ins_nr, inode_only);
if (ret) {
err = ret;
goto out_unlock;
}
ins_nr = 0;
}
btrfs_release_path(root, path);
if (min_key.offset < (u64)-1)
min_key.offset++;
else if (min_key.type < (u8)-1)
min_key.type++;
else if (min_key.objectid < (u64)-1)
min_key.objectid++;
else
break;
}
if (ins_nr) {
ret = copy_items(trans, log, dst_path, src,
ins_start_slot,
ins_nr, inode_only);
if (ret) {
err = ret;
goto out_unlock;
}
ins_nr = 0;
}
WARN_ON(ins_nr);
if (inode_only == LOG_INODE_ALL && S_ISDIR(inode->i_mode)) {
btrfs_release_path(root, path);
btrfs_release_path(log, dst_path);
ret = log_directory_changes(trans, root, inode, path, dst_path);
if (ret) {
err = ret;
goto out_unlock;
}
}
BTRFS_I(inode)->logged_trans = trans->transid;
out_unlock:
mutex_unlock(&BTRFS_I(inode)->log_mutex);
btrfs_free_path(path);
btrfs_free_path(dst_path);
return err;
}
/*
* follow the dentry parent pointers up the chain and see if any
* of the directories in it require a full commit before they can
* be logged. Returns zero if nothing special needs to be done or 1 if
* a full commit is required.
*/
static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans,
struct inode *inode,
struct dentry *parent,
struct super_block *sb,
u64 last_committed)
{
int ret = 0;
struct btrfs_root *root;
struct dentry *old_parent = NULL;
/*
* for regular files, if its inode is already on disk, we don't
* have to worry about the parents at all. This is because
* we can use the last_unlink_trans field to record renames
* and other fun in this file.
*/
if (S_ISREG(inode->i_mode) &&
BTRFS_I(inode)->generation <= last_committed &&
BTRFS_I(inode)->last_unlink_trans <= last_committed)
goto out;
if (!S_ISDIR(inode->i_mode)) {
if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
goto out;
inode = parent->d_inode;
}
while (1) {
BTRFS_I(inode)->logged_trans = trans->transid;
smp_mb();
if (BTRFS_I(inode)->last_unlink_trans > last_committed) {
root = BTRFS_I(inode)->root;
/*
* make sure any commits to the log are forced
* to be full commits
*/
root->fs_info->last_trans_log_full_commit =
trans->transid;
ret = 1;
break;
}
if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
break;
if (IS_ROOT(parent))
break;
parent = dget_parent(parent);
dput(old_parent);
old_parent = parent;
inode = parent->d_inode;
}
dput(old_parent);
out:
return ret;
}
static int inode_in_log(struct btrfs_trans_handle *trans,
struct inode *inode)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret = 0;
mutex_lock(&root->log_mutex);
if (BTRFS_I(inode)->logged_trans == trans->transid &&
BTRFS_I(inode)->last_sub_trans <= root->last_log_commit)
ret = 1;
mutex_unlock(&root->log_mutex);
return ret;
}
/*
* helper function around btrfs_log_inode to make sure newly created
* parent directories also end up in the log. A minimal inode and backref
* only logging is done of any parent directories that are older than
* the last committed transaction
*/
int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
struct dentry *parent, int exists_only)
{
int inode_only = exists_only ? LOG_INODE_EXISTS : LOG_INODE_ALL;
struct super_block *sb;
struct dentry *old_parent = NULL;
int ret = 0;
u64 last_committed = root->fs_info->last_trans_committed;
sb = inode->i_sb;
if (btrfs_test_opt(root, NOTREELOG)) {
ret = 1;
goto end_no_trans;
}
if (root->fs_info->last_trans_log_full_commit >
root->fs_info->last_trans_committed) {
ret = 1;
goto end_no_trans;
}
if (root != BTRFS_I(inode)->root ||
btrfs_root_refs(&root->root_item) == 0) {
ret = 1;
goto end_no_trans;
}
ret = check_parent_dirs_for_sync(trans, inode, parent,
sb, last_committed);
if (ret)
goto end_no_trans;
if (inode_in_log(trans, inode)) {
ret = BTRFS_NO_LOG_SYNC;
goto end_no_trans;
}
ret = start_log_trans(trans, root);
if (ret)
goto end_trans;
ret = btrfs_log_inode(trans, root, inode, inode_only);
if (ret)
goto end_trans;
/*
* for regular files, if its inode is already on disk, we don't
* have to worry about the parents at all. This is because
* we can use the last_unlink_trans field to record renames
* and other fun in this file.
*/
if (S_ISREG(inode->i_mode) &&
BTRFS_I(inode)->generation <= last_committed &&
BTRFS_I(inode)->last_unlink_trans <= last_committed) {
ret = 0;
goto end_trans;
}
inode_only = LOG_INODE_EXISTS;
while (1) {
if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
break;
inode = parent->d_inode;
if (root != BTRFS_I(inode)->root)
break;
if (BTRFS_I(inode)->generation >
root->fs_info->last_trans_committed) {
ret = btrfs_log_inode(trans, root, inode, inode_only);
if (ret)
goto end_trans;
}
if (IS_ROOT(parent))
break;
parent = dget_parent(parent);
dput(old_parent);
old_parent = parent;
}
ret = 0;
end_trans:
dput(old_parent);
if (ret < 0) {
BUG_ON(ret != -ENOSPC);
root->fs_info->last_trans_log_full_commit = trans->transid;
ret = 1;
}
btrfs_end_log_trans(root);
end_no_trans:
return ret;
}
/*
* it is not safe to log dentry if the chunk root has added new
* chunks. This returns 0 if the dentry was logged, and 1 otherwise.
* If this returns 1, you must commit the transaction to safely get your
* data on disk.
*/
int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct dentry *dentry)
{
struct dentry *parent = dget_parent(dentry);
int ret;
ret = btrfs_log_inode_parent(trans, root, dentry->d_inode, parent, 0);
dput(parent);
return ret;
}
/*
* should be called during mount to recover any replay any log trees
* from the FS
*/
int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
{
int ret;
struct btrfs_path *path;
struct btrfs_trans_handle *trans;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_key tmp_key;
struct btrfs_root *log;
struct btrfs_fs_info *fs_info = log_root_tree->fs_info;
struct walk_control wc = {
.process_func = process_one_buffer,
.stage = 0,
};
fs_info->log_root_recovering = 1;
path = btrfs_alloc_path();
BUG_ON(!path);
trans = btrfs_start_transaction(fs_info->tree_root, 0);
wc.trans = trans;
wc.pin = 1;
walk_log_tree(trans, log_root_tree, &wc);
again:
key.objectid = BTRFS_TREE_LOG_OBJECTID;
key.offset = (u64)-1;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
while (1) {
ret = btrfs_search_slot(NULL, log_root_tree, &key, path, 0, 0);
if (ret < 0)
break;
if (ret > 0) {
if (path->slots[0] == 0)
break;
path->slots[0]--;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
btrfs_release_path(log_root_tree, path);
if (found_key.objectid != BTRFS_TREE_LOG_OBJECTID)
break;
log = btrfs_read_fs_root_no_radix(log_root_tree,
&found_key);
BUG_ON(!log);
tmp_key.objectid = found_key.offset;
tmp_key.type = BTRFS_ROOT_ITEM_KEY;
tmp_key.offset = (u64)-1;
wc.replay_dest = btrfs_read_fs_root_no_name(fs_info, &tmp_key);
BUG_ON(!wc.replay_dest);
wc.replay_dest->log_root = log;
btrfs_record_root_in_trans(trans, wc.replay_dest);
ret = walk_log_tree(trans, log, &wc);
BUG_ON(ret);
if (wc.stage == LOG_WALK_REPLAY_ALL) {
ret = fixup_inode_link_counts(trans, wc.replay_dest,
path);
BUG_ON(ret);
}
key.offset = found_key.offset - 1;
wc.replay_dest->log_root = NULL;
free_extent_buffer(log->node);
free_extent_buffer(log->commit_root);
kfree(log);
if (found_key.offset == 0)
break;
}
btrfs_release_path(log_root_tree, path);
/* step one is to pin it all, step two is to replay just inodes */
if (wc.pin) {
wc.pin = 0;
wc.process_func = replay_one_buffer;
wc.stage = LOG_WALK_REPLAY_INODES;
goto again;
}
/* step three is to replay everything */
if (wc.stage < LOG_WALK_REPLAY_ALL) {
wc.stage++;
goto again;
}
btrfs_free_path(path);
free_extent_buffer(log_root_tree->node);
log_root_tree->log_root = NULL;
fs_info->log_root_recovering = 0;
/* step 4: commit the transaction, which also unpins the blocks */
btrfs_commit_transaction(trans, fs_info->tree_root);
kfree(log_root_tree);
return 0;
}
/*
* there are some corner cases where we want to force a full
* commit instead of allowing a directory to be logged.
*
* They revolve around files there were unlinked from the directory, and
* this function updates the parent directory so that a full commit is
* properly done if it is fsync'd later after the unlinks are done.
*/
void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans,
struct inode *dir, struct inode *inode,
int for_rename)
{
/*
* when we're logging a file, if it hasn't been renamed
* or unlinked, and its inode is fully committed on disk,
* we don't have to worry about walking up the directory chain
* to log its parents.
*
* So, we use the last_unlink_trans field to put this transid
* into the file. When the file is logged we check it and
* don't log the parents if the file is fully on disk.
*/
if (S_ISREG(inode->i_mode))
BTRFS_I(inode)->last_unlink_trans = trans->transid;
/*
* if this directory was already logged any new
* names for this file/dir will get recorded
*/
smp_mb();
if (BTRFS_I(dir)->logged_trans == trans->transid)
return;
/*
* if the inode we're about to unlink was logged,
* the log will be properly updated for any new names
*/
if (BTRFS_I(inode)->logged_trans == trans->transid)
return;
/*
* when renaming files across directories, if the directory
* there we're unlinking from gets fsync'd later on, there's
* no way to find the destination directory later and fsync it
* properly. So, we have to be conservative and force commits
* so the new name gets discovered.
*/
if (for_rename)
goto record;
/* we can safely do the unlink without any special recording */
return;
record:
BTRFS_I(dir)->last_unlink_trans = trans->transid;
}
/*
* Call this after adding a new name for a file and it will properly
* update the log to reflect the new name.
*
* It will return zero if all goes well, and it will return 1 if a
* full transaction commit is required.
*/
int btrfs_log_new_name(struct btrfs_trans_handle *trans,
struct inode *inode, struct inode *old_dir,
struct dentry *parent)
{
struct btrfs_root * root = BTRFS_I(inode)->root;
/*
* this will force the logging code to walk the dentry chain
* up for the file
*/
if (S_ISREG(inode->i_mode))
BTRFS_I(inode)->last_unlink_trans = trans->transid;
/*
* if this inode hasn't been logged and directory we're renaming it
* from hasn't been logged, we don't need to log it
*/
if (BTRFS_I(inode)->logged_trans <=
root->fs_info->last_trans_committed &&
(!old_dir || BTRFS_I(old_dir)->logged_trans <=
root->fs_info->last_trans_committed))
return 0;
return btrfs_log_inode_parent(trans, root, inode, parent, 1);
}
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