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OpenCloudOS-Kernel/fs/btrfs/reflink.c

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// SPDX-License-Identifier: GPL-2.0
#include <linux/blkdev.h>
#include <linux/iversion.h>
#include "ctree.h"
#include "fs.h"
#include "messages.h"
#include "compression.h"
#include "delalloc-space.h"
#include "disk-io.h"
#include "reflink.h"
#include "transaction.h"
#include "subpage.h"
#include "accessors.h"
#include "file-item.h"
#include "file.h"
#include "super.h"
#define BTRFS_MAX_DEDUPE_LEN SZ_16M
static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
struct inode *inode,
u64 endoff,
const u64 destoff,
const u64 olen,
int no_time_update)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
inode_inc_iversion(inode);
if (!no_time_update) {
inode->i_mtime = inode_set_ctime_current(inode);
}
/*
* We round up to the block size at eof when determining which
* extents to clone above, but shouldn't round up the file size.
*/
if (endoff > destoff + olen)
endoff = destoff + olen;
if (endoff > inode->i_size) {
i_size_write(inode, endoff);
btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
}
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
if (ret) {
btrfs_abort_transaction(trans, ret);
btrfs_end_transaction(trans);
goto out;
}
ret = btrfs_end_transaction(trans);
out:
return ret;
}
static int copy_inline_to_page(struct btrfs_inode *inode,
const u64 file_offset,
char *inline_data,
const u64 size,
const u64 datal,
const u8 comp_type)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
const u32 block_size = fs_info->sectorsize;
const u64 range_end = file_offset + block_size - 1;
const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
struct extent_changeset *data_reserved = NULL;
struct page *page = NULL;
struct address_space *mapping = inode->vfs_inode.i_mapping;
int ret;
ASSERT(IS_ALIGNED(file_offset, block_size));
/*
* We have flushed and locked the ranges of the source and destination
* inodes, we also have locked the inodes, so we are safe to do a
* reservation here. Also we must not do the reservation while holding
* a transaction open, otherwise we would deadlock.
*/
ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,
block_size);
if (ret)
goto out;
page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT,
btrfs_alloc_write_mask(mapping));
if (!page) {
ret = -ENOMEM;
goto out_unlock;
}
ret = set_page_extent_mapped(page);
if (ret < 0)
goto out_unlock;
clear_extent_bit(&inode->io_tree, file_offset, range_end,
EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
NULL);
ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);
if (ret)
goto out_unlock;
/*
* After dirtying the page our caller will need to start a transaction,
* and if we are low on metadata free space, that can cause flushing of
* delalloc for all inodes in order to get metadata space released.
* However we are holding the range locked for the whole duration of
* the clone/dedupe operation, so we may deadlock if that happens and no
* other task releases enough space. So mark this inode as not being
* possible to flush to avoid such deadlock. We will clear that flag
* when we finish cloning all extents, since a transaction is started
* after finding each extent to clone.
*/
set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
if (comp_type == BTRFS_COMPRESS_NONE) {
memcpy_to_page(page, offset_in_page(file_offset), data_start,
datal);
} else {
ret = btrfs_decompress(comp_type, data_start, page,
offset_in_page(file_offset),
inline_size, datal);
if (ret)
goto out_unlock;
flush_dcache_page(page);
}
/*
* If our inline data is smaller then the block/page size, then the
* remaining of the block/page is equivalent to zeroes. We had something
* like the following done:
*
* $ xfs_io -f -c "pwrite -S 0xab 0 500" file
* $ sync # (or fsync)
* $ xfs_io -c "falloc 0 4K" file
* $ xfs_io -c "pwrite -S 0xcd 4K 4K"
*
* So what's in the range [500, 4095] corresponds to zeroes.
*/
if (datal < block_size)
memzero_page(page, datal, block_size - datal);
btrfs_page_set_uptodate(fs_info, page, file_offset, block_size);
btrfs_page_clear_checked(fs_info, page, file_offset, block_size);
btrfs_page_set_dirty(fs_info, page, file_offset, block_size);
out_unlock:
if (page) {
unlock_page(page);
put_page(page);
}
if (ret)
btrfs_delalloc_release_space(inode, data_reserved, file_offset,
block_size, true);
btrfs_delalloc_release_extents(inode, block_size);
out:
extent_changeset_free(data_reserved);
return ret;
}
/*
* Deal with cloning of inline extents. We try to copy the inline extent from
* the source inode to destination inode when possible. When not possible we
* copy the inline extent's data into the respective page of the inode.
*/
static int clone_copy_inline_extent(struct inode *dst,
struct btrfs_path *path,
struct btrfs_key *new_key,
const u64 drop_start,
const u64 datal,
const u64 size,
const u8 comp_type,
char *inline_data,
struct btrfs_trans_handle **trans_out)
{
struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
struct btrfs_root *root = BTRFS_I(dst)->root;
const u64 aligned_end = ALIGN(new_key->offset + datal,
fs_info->sectorsize);
struct btrfs_trans_handle *trans = NULL;
struct btrfs_drop_extents_args drop_args = { 0 };
int ret;
struct btrfs_key key;
if (new_key->offset > 0) {
ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
inline_data, size, datal, comp_type);
goto out;
}
key.objectid = btrfs_ino(BTRFS_I(dst));
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0) {
return ret;
} else if (ret > 0) {
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
return ret;
else if (ret > 0)
goto copy_inline_extent;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
key.type == BTRFS_EXTENT_DATA_KEY) {
/*
* There's an implicit hole at file offset 0, copy the
* inline extent's data to the page.
*/
ASSERT(key.offset > 0);
goto copy_to_page;
}
} else if (i_size_read(dst) <= datal) {
struct btrfs_file_extent_item *ei;
ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
/*
* If it's an inline extent replace it with the source inline
* extent, otherwise copy the source inline extent data into
* the respective page at the destination inode.
*/
if (btrfs_file_extent_type(path->nodes[0], ei) ==
BTRFS_FILE_EXTENT_INLINE)
goto copy_inline_extent;
goto copy_to_page;
}
copy_inline_extent:
/*
* We have no extent items, or we have an extent at offset 0 which may
* or may not be inlined. All these cases are dealt the same way.
*/
if (i_size_read(dst) > datal) {
/*
* At the destination offset 0 we have either a hole, a regular
* extent or an inline extent larger then the one we want to
* clone. Deal with all these cases by copying the inline extent
* data into the respective page at the destination inode.
*/
goto copy_to_page;
}
/*
* Release path before starting a new transaction so we don't hold locks
* that would confuse lockdep.
*/
btrfs_release_path(path);
/*
* If we end up here it means were copy the inline extent into a leaf
* of the destination inode. We know we will drop or adjust at most one
* extent item in the destination root.
*
* 1 unit - adjusting old extent (we may have to split it)
* 1 unit - add new extent
* 1 unit - inode update
*/
trans = btrfs_start_transaction(root, 3);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
goto out;
}
drop_args.path = path;
drop_args.start = drop_start;
drop_args.end = aligned_end;
drop_args.drop_cache = true;
ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);
if (ret)
goto out;
ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
if (ret)
goto out;
write_extent_buffer(path->nodes[0], inline_data,
btrfs_item_ptr_offset(path->nodes[0],
path->slots[0]),
size);
btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);
btrfs_set_inode_full_sync(BTRFS_I(dst));
ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);
out:
if (!ret && !trans) {
/*
* No transaction here means we copied the inline extent into a
* page of the destination inode.
*
* 1 unit to update inode item
*/
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
}
}
if (ret && trans) {
btrfs_abort_transaction(trans, ret);
btrfs_end_transaction(trans);
}
if (!ret)
*trans_out = trans;
return ret;
copy_to_page:
/*
* Release our path because we don't need it anymore and also because
* copy_inline_to_page() needs to reserve data and metadata, which may
* need to flush delalloc when we are low on available space and
* therefore cause a deadlock if writeback of an inline extent needs to
* write to the same leaf or an ordered extent completion needs to write
* to the same leaf.
*/
btrfs_release_path(path);
ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
inline_data, size, datal, comp_type);
goto out;
}
/*
* Clone a range from inode file to another.
*
* @src: Inode to clone from
* @inode: Inode to clone to
* @off: Offset within source to start clone from
* @olen: Original length, passed by user, of range to clone
* @olen_aligned: Block-aligned value of olen
* @destoff: Offset within @inode to start clone
* @no_time_update: Whether to update mtime/ctime on the target inode
*/
static int btrfs_clone(struct inode *src, struct inode *inode,
const u64 off, const u64 olen, const u64 olen_aligned,
const u64 destoff, int no_time_update)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_path *path = NULL;
struct extent_buffer *leaf;
struct btrfs_trans_handle *trans;
char *buf = NULL;
struct btrfs_key key;
u32 nritems;
int slot;
int ret;
const u64 len = olen_aligned;
u64 last_dest_end = destoff;
u64 prev_extent_end = off;
ret = -ENOMEM;
buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
if (!buf)
return ret;
path = btrfs_alloc_path();
if (!path) {
kvfree(buf);
return ret;
}
path->reada = READA_FORWARD;
/* Clone data */
key.objectid = btrfs_ino(BTRFS_I(src));
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = off;
while (1) {
struct btrfs_file_extent_item *extent;
u64 extent_gen;
int type;
u32 size;
struct btrfs_key new_key;
u64 disko = 0, diskl = 0;
u64 datao = 0, datal = 0;
u8 comp;
u64 drop_start;
/* Note the key will change type as we walk through the tree */
ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
0, 0);
if (ret < 0)
goto out;
/*
* First search, if no extent item that starts at offset off was
* found but the previous item is an extent item, it's possible
* it might overlap our target range, therefore process it.
*/
if (key.offset == off && ret > 0 && path->slots[0] > 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0] - 1);
if (key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
nritems = btrfs_header_nritems(path->nodes[0]);
process_slot:
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
if (ret < 0)
goto out;
if (ret > 0)
break;
nritems = btrfs_header_nritems(path->nodes[0]);
}
leaf = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.type > BTRFS_EXTENT_DATA_KEY ||
key.objectid != btrfs_ino(BTRFS_I(src)))
break;
ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
extent_gen = btrfs_file_extent_generation(leaf, extent);
comp = btrfs_file_extent_compression(leaf, extent);
type = btrfs_file_extent_type(leaf, extent);
if (type == BTRFS_FILE_EXTENT_REG ||
type == BTRFS_FILE_EXTENT_PREALLOC) {
disko = btrfs_file_extent_disk_bytenr(leaf, extent);
diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
datao = btrfs_file_extent_offset(leaf, extent);
datal = btrfs_file_extent_num_bytes(leaf, extent);
} else if (type == BTRFS_FILE_EXTENT_INLINE) {
/* Take upper bound, may be compressed */
datal = btrfs_file_extent_ram_bytes(leaf, extent);
}
/*
* The first search might have left us at an extent item that
* ends before our target range's start, can happen if we have
* holes and NO_HOLES feature enabled.
*
* Subsequent searches may leave us on a file range we have
* processed before - this happens due to a race with ordered
* extent completion for a file range that is outside our source
* range, but that range was part of a file extent item that
* also covered a leading part of our source range.
*/
if (key.offset + datal <= prev_extent_end) {
path->slots[0]++;
goto process_slot;
} else if (key.offset >= off + len) {
break;
}
prev_extent_end = key.offset + datal;
size = btrfs_item_size(leaf, slot);
read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
size);
btrfs_release_path(path);
memcpy(&new_key, &key, sizeof(new_key));
new_key.objectid = btrfs_ino(BTRFS_I(inode));
if (off <= key.offset)
new_key.offset = key.offset + destoff - off;
else
new_key.offset = destoff;
/*
* Deal with a hole that doesn't have an extent item that
* represents it (NO_HOLES feature enabled).
* This hole is either in the middle of the cloning range or at
* the beginning (fully overlaps it or partially overlaps it).
*/
if (new_key.offset != last_dest_end)
drop_start = last_dest_end;
else
drop_start = new_key.offset;
if (type == BTRFS_FILE_EXTENT_REG ||
type == BTRFS_FILE_EXTENT_PREALLOC) {
struct btrfs_replace_extent_info clone_info;
/*
* a | --- range to clone ---| b
* | ------------- extent ------------- |
*/
/* Subtract range b */
if (key.offset + datal > off + len)
datal = off + len - key.offset;
/* Subtract range a */
if (off > key.offset) {
datao += off - key.offset;
datal -= off - key.offset;
}
clone_info.disk_offset = disko;
clone_info.disk_len = diskl;
clone_info.data_offset = datao;
clone_info.data_len = datal;
clone_info.file_offset = new_key.offset;
clone_info.extent_buf = buf;
clone_info.is_new_extent = false;
clone_info.update_times = !no_time_update;
ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
drop_start, new_key.offset + datal - 1,
&clone_info, &trans);
if (ret)
goto out;
} else {
ASSERT(type == BTRFS_FILE_EXTENT_INLINE);
/*
* Inline extents always have to start at file offset 0
* and can never be bigger then the sector size. We can
* never clone only parts of an inline extent, since all
* reflink operations must start at a sector size aligned
* offset, and the length must be aligned too or end at
* the i_size (which implies the whole inlined data).
*/
ASSERT(key.offset == 0);
ASSERT(datal <= fs_info->sectorsize);
if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) ||
WARN_ON(key.offset != 0) ||
WARN_ON(datal > fs_info->sectorsize)) {
ret = -EUCLEAN;
goto out;
}
ret = clone_copy_inline_extent(inode, path, &new_key,
drop_start, datal, size,
comp, buf, &trans);
if (ret)
goto out;
}
btrfs_release_path(path);
/*
* Whenever we share an extent we update the last_reflink_trans
* of each inode to the current transaction. This is needed to
* make sure fsync does not log multiple checksum items with
* overlapping ranges (because some extent items might refer
* only to sections of the original extent). For the destination
* inode we do this regardless of the generation of the extents
* or even if they are inline extents or explicit holes, to make
* sure a full fsync does not skip them. For the source inode,
* we only need to update last_reflink_trans in case it's a new
* extent that is not a hole or an inline extent, to deal with
* the checksums problem on fsync.
*/
if (extent_gen == trans->transid && disko > 0)
BTRFS_I(src)->last_reflink_trans = trans->transid;
BTRFS_I(inode)->last_reflink_trans = trans->transid;
last_dest_end = ALIGN(new_key.offset + datal,
fs_info->sectorsize);
ret = clone_finish_inode_update(trans, inode, last_dest_end,
destoff, olen, no_time_update);
if (ret)
goto out;
if (new_key.offset + datal >= destoff + len)
break;
btrfs_release_path(path);
key.offset = prev_extent_end;
if (fatal_signal_pending(current)) {
ret = -EINTR;
goto out;
}
cond_resched();
}
ret = 0;
if (last_dest_end < destoff + len) {
/*
* We have an implicit hole that fully or partially overlaps our
* cloning range at its end. This means that we either have the
* NO_HOLES feature enabled or the implicit hole happened due to
* mixing buffered and direct IO writes against this file.
*/
btrfs_release_path(path);
/*
* When using NO_HOLES and we are cloning a range that covers
* only a hole (no extents) into a range beyond the current
* i_size, punching a hole in the target range will not create
* an extent map defining a hole, because the range starts at or
* beyond current i_size. If the file previously had an i_size
* greater than the new i_size set by this clone operation, we
* need to make sure the next fsync is a full fsync, so that it
* detects and logs a hole covering a range from the current
* i_size to the new i_size. If the clone range covers extents,
* besides a hole, then we know the full sync flag was already
* set by previous calls to btrfs_replace_file_extents() that
* replaced file extent items.
*/
if (last_dest_end >= i_size_read(inode))
btrfs_set_inode_full_sync(BTRFS_I(inode));
ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
last_dest_end, destoff + len - 1, NULL, &trans);
if (ret)
goto out;
ret = clone_finish_inode_update(trans, inode, destoff + len,
destoff, olen, no_time_update);
}
out:
btrfs_free_path(path);
kvfree(buf);
clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
return ret;
}
static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
struct inode *inode2, u64 loff2, u64 len)
{
unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1, NULL);
unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1, NULL);
}
static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
struct inode *inode2, u64 loff2, u64 len)
{
u64 range1_end = loff1 + len - 1;
u64 range2_end = loff2 + len - 1;
if (inode1 < inode2) {
swap(inode1, inode2);
swap(loff1, loff2);
swap(range1_end, range2_end);
} else if (inode1 == inode2 && loff2 < loff1) {
swap(loff1, loff2);
swap(range1_end, range2_end);
}
lock_extent(&BTRFS_I(inode1)->io_tree, loff1, range1_end, NULL);
lock_extent(&BTRFS_I(inode2)->io_tree, loff2, range2_end, NULL);
btrfs_assert_inode_range_clean(BTRFS_I(inode1), loff1, range1_end);
btrfs_assert_inode_range_clean(BTRFS_I(inode2), loff2, range2_end);
}
static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)
{
if (inode1 < inode2)
swap(inode1, inode2);
down_write(&BTRFS_I(inode1)->i_mmap_lock);
down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);
}
static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)
{
up_write(&BTRFS_I(inode1)->i_mmap_lock);
up_write(&BTRFS_I(inode2)->i_mmap_lock);
}
static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
struct inode *dst, u64 dst_loff)
{
struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info;
const u64 bs = fs_info->sb->s_blocksize;
int ret;
/*
* Lock destination range to serialize with concurrent readahead() and
* source range to serialize with relocation.
*/
btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);
btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
btrfs_btree_balance_dirty(fs_info);
return ret;
}
static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
struct inode *dst, u64 dst_loff)
{
int ret = 0;
u64 i, tail_len, chunk_count;
struct btrfs_root *root_dst = BTRFS_I(dst)->root;
spin_lock(&root_dst->root_item_lock);
if (root_dst->send_in_progress) {
btrfs_warn_rl(root_dst->fs_info,
"cannot deduplicate to root %llu while send operations are using it (%d in progress)",
root_dst->root_key.objectid,
root_dst->send_in_progress);
spin_unlock(&root_dst->root_item_lock);
return -EAGAIN;
}
root_dst->dedupe_in_progress++;
spin_unlock(&root_dst->root_item_lock);
tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
for (i = 0; i < chunk_count; i++) {
ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
dst, dst_loff);
if (ret)
goto out;
loff += BTRFS_MAX_DEDUPE_LEN;
dst_loff += BTRFS_MAX_DEDUPE_LEN;
}
if (tail_len > 0)
ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);
out:
spin_lock(&root_dst->root_item_lock);
root_dst->dedupe_in_progress--;
spin_unlock(&root_dst->root_item_lock);
return ret;
}
static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
u64 off, u64 olen, u64 destoff)
{
struct inode *inode = file_inode(file);
struct inode *src = file_inode(file_src);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
int ret;
int wb_ret;
u64 len = olen;
u64 bs = fs_info->sb->s_blocksize;
/*
* VFS's generic_remap_file_range_prep() protects us from cloning the
* eof block into the middle of a file, which would result in corruption
* if the file size is not blocksize aligned. So we don't need to check
* for that case here.
*/
if (off + len == src->i_size)
len = ALIGN(src->i_size, bs) - off;
if (destoff > inode->i_size) {
const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);
if (ret)
return ret;
/*
* We may have truncated the last block if the inode's size is
* not sector size aligned, so we need to wait for writeback to
* complete before proceeding further, otherwise we can race
* with cloning and attempt to increment a reference to an
* extent that no longer exists (writeback completed right after
* we found the previous extent covering eof and before we
* attempted to increment its reference count).
*/
ret = btrfs_wait_ordered_range(inode, wb_start,
destoff - wb_start);
if (ret)
return ret;
}
/*
* Lock destination range to serialize with concurrent readahead() and
* source range to serialize with relocation.
*/
btrfs_double_extent_lock(src, off, inode, destoff, len);
ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
btrfs_double_extent_unlock(src, off, inode, destoff, len);
/*
* We may have copied an inline extent into a page of the destination
* range, so wait for writeback to complete before truncating pages
* from the page cache. This is a rare case.
*/
wb_ret = btrfs_wait_ordered_range(inode, destoff, len);
ret = ret ? ret : wb_ret;
/*
* Truncate page cache pages so that future reads will see the cloned
* data immediately and not the previous data.
*/
truncate_inode_pages_range(&inode->i_data,
round_down(destoff, PAGE_SIZE),
round_up(destoff + len, PAGE_SIZE) - 1);
btrfs_btree_balance_dirty(fs_info);
return ret;
}
static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t *len, unsigned int remap_flags)
{
struct inode *inode_in = file_inode(file_in);
struct inode *inode_out = file_inode(file_out);
u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
u64 wb_len;
int ret;
if (!(remap_flags & REMAP_FILE_DEDUP)) {
struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
if (btrfs_root_readonly(root_out))
return -EROFS;
ASSERT(inode_in->i_sb == inode_out->i_sb);
}
/* Don't make the dst file partly checksummed */
if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
(BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
return -EINVAL;
}
/*
* Now that the inodes are locked, we need to start writeback ourselves
* and can not rely on the writeback from the VFS's generic helper
* generic_remap_file_range_prep() because:
*
* 1) For compression we must call filemap_fdatawrite_range() range
* twice (btrfs_fdatawrite_range() does it for us), and the generic
* helper only calls it once;
*
* 2) filemap_fdatawrite_range(), called by the generic helper only
* waits for the writeback to complete, i.e. for IO to be done, and
* not for the ordered extents to complete. We need to wait for them
* to complete so that new file extent items are in the fs tree.
*/
if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
else
wb_len = ALIGN(*len, bs);
/*
* Workaround to make sure NOCOW buffered write reach disk as NOCOW.
*
* Btrfs' back references do not have a block level granularity, they
* work at the whole extent level.
* NOCOW buffered write without data space reserved may not be able
* to fall back to CoW due to lack of data space, thus could cause
* data loss.
*
* Here we take a shortcut by flushing the whole inode, so that all
* nocow write should reach disk as nocow before we increase the
* reference of the extent. We could do better by only flushing NOCOW
* data, but that needs extra accounting.
*
* Also we don't need to check ASYNC_EXTENT, as async extent will be
* CoWed anyway, not affecting nocow part.
*/
ret = filemap_flush(inode_in->i_mapping);
if (ret < 0)
return ret;
ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs),
wb_len);
if (ret < 0)
return ret;
ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs),
wb_len);
if (ret < 0)
return ret;
return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
len, remap_flags);
}
static bool file_sync_write(const struct file *file)
{
if (file->f_flags & (__O_SYNC | O_DSYNC))
return true;
if (IS_SYNC(file_inode(file)))
return true;
return false;
}
loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
struct file *dst_file, loff_t destoff, loff_t len,
unsigned int remap_flags)
{
struct inode *src_inode = file_inode(src_file);
struct inode *dst_inode = file_inode(dst_file);
bool same_inode = dst_inode == src_inode;
int ret;
if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
return -EINVAL;
if (same_inode) {
btrfs_inode_lock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
} else {
lock_two_nondirectories(src_inode, dst_inode);
btrfs_double_mmap_lock(src_inode, dst_inode);
}
ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
&len, remap_flags);
if (ret < 0 || len == 0)
goto out_unlock;
if (remap_flags & REMAP_FILE_DEDUP)
ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
else
ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
out_unlock:
if (same_inode) {
btrfs_inode_unlock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
} else {
btrfs_double_mmap_unlock(src_inode, dst_inode);
unlock_two_nondirectories(src_inode, dst_inode);
}
/*
* If either the source or the destination file was opened with O_SYNC,
* O_DSYNC or has the S_SYNC attribute, fsync both the destination and
* source files/ranges, so that after a successful return (0) followed
* by a power failure results in the reflinked data to be readable from
* both files/ranges.
*/
if (ret == 0 && len > 0 &&
(file_sync_write(src_file) || file_sync_write(dst_file))) {
ret = btrfs_sync_file(src_file, off, off + len - 1, 0);
if (ret == 0)
ret = btrfs_sync_file(dst_file, destoff,
destoff + len - 1, 0);
}
return ret < 0 ? ret : len;
}
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