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Btrfs: simplify inline extent handling when doing reflinks

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We can not reflink parts of an inline extent, we must always reflink the
whole inline extent. We know that inline extents always start at file
offset 0 and that can never represent an amount of data larger then the
filesystem's sector size (both compressed and uncompressed). We also have
had the constraints that reflink operations must have a start offset that
is aligned to the sector size and an end offset that is also aligned or
it ends the inode's i_size, so there's no way for user space to be able
to do a reflink operation that will refer to only a part of an inline
extent.

Initially there was a bug in the inlining code that could allow compressed
inline extents that encoded more than 1 page, but that was fixed in 2008
by commit 70b99e6959 ("Btrfs: Compression corner fixes") since that
was problematic.

So remove all the extent cloning code that deals with the possibility
of cloning only partial inline extents.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2020-02-28 13:04:18 +00:00 committed by David Sterba
parent 6a17738100
commit a61e1e0df9
1 changed files with 14 additions and 39 deletions
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53
fs/btrfs/reflink.c
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@ -73,9 +73,8 @@ static int clone_copy_inline_extent(struct inode *dst,
struct btrfs_key *new_key, struct btrfs_key *new_key,
const u64 drop_start, const u64 drop_start,
const u64 datal, const u64 datal,
const u64 skip,
const u64 size, const u64 size,
char *inline_data) const char *inline_data)
{ {
struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb); struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
struct btrfs_root *root = BTRFS_I(dst)->root; struct btrfs_root *root = BTRFS_I(dst)->root;
@ -171,12 +170,6 @@ copy_inline_extent:
if (ret) if (ret)
return ret; return ret;
if (skip) {
const u32 start = btrfs_file_extent_calc_inline_size(0);
memmove(inline_data + start, inline_data + start + skip, datal);
}
write_extent_buffer(path->nodes[0], inline_data, write_extent_buffer(path->nodes[0], inline_data,
btrfs_item_ptr_offset(path->nodes[0], btrfs_item_ptr_offset(path->nodes[0],
path->slots[0]), path->slots[0]),
@ -240,7 +233,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
struct btrfs_key new_key; struct btrfs_key new_key;
u64 disko = 0, diskl = 0; u64 disko = 0, diskl = 0;
u64 datao = 0, datal = 0; u64 datao = 0, datal = 0;
u8 comp;
u64 drop_start; u64 drop_start;
/* Note the key will change type as we walk through the tree */ /* Note the key will change type as we walk through the tree */
@ -283,7 +275,6 @@ process_slot:
extent = btrfs_item_ptr(leaf, slot, extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item); struct btrfs_file_extent_item);
comp = btrfs_file_extent_compression(leaf, extent);
type = btrfs_file_extent_type(leaf, extent); type = btrfs_file_extent_type(leaf, extent);
if (type == BTRFS_FILE_EXTENT_REG || if (type == BTRFS_FILE_EXTENT_REG ||
type == BTRFS_FILE_EXTENT_PREALLOC) { type == BTRFS_FILE_EXTENT_PREALLOC) {
@ -365,23 +356,18 @@ process_slot:
if (ret) if (ret)
goto out; goto out;
} else if (type == BTRFS_FILE_EXTENT_INLINE) { } else if (type == BTRFS_FILE_EXTENT_INLINE) {
u64 skip = 0; /*
u64 trim = 0; * Inline extents always have to start at file offset 0
* and can never be bigger then the sector size. We can
if (off > key.offset) { * never clone only parts of an inline extent, since all
skip = off - key.offset; * reflink operations must start at a sector size aligned
new_key.offset += skip; * offset, and the length must be aligned too or end at
} * the i_size (which implies the whole inlined data).
*/
if (key.offset + datal > off + len) ASSERT(key.offset == 0);
trim = key.offset + datal - (off + len); ASSERT(datal <= fs_info->sectorsize);
if (key.offset != 0 || datal > fs_info->sectorsize)
if (comp && (skip || trim)) { return -EUCLEAN;
ret = -EINVAL;
goto out;
}
size -= skip + trim;
datal -= skip + trim;
/* /*
* If our extent is inline, we know we will drop or * If our extent is inline, we know we will drop or
@ -399,7 +385,7 @@ process_slot:
ret = clone_copy_inline_extent(inode, trans, path, ret = clone_copy_inline_extent(inode, trans, path,
&new_key, drop_start, &new_key, drop_start,
datal, skip, size, buf); datal, size, buf);
if (ret) { if (ret) {
if (ret != -EOPNOTSUPP) if (ret != -EOPNOTSUPP)
btrfs_abort_transaction(trans, ret); btrfs_abort_transaction(trans, ret);
@ -543,17 +529,6 @@ static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
u64 len = olen; u64 len = olen;
u64 bs = fs_info->sb->s_blocksize; u64 bs = fs_info->sb->s_blocksize;
/*
* TODO:
* - split compressed inline extents. annoying: we need to
* decompress into destination's address_space (the file offset
* may change, so source mapping won't do), then recompress (or
* otherwise reinsert) a subrange.
*
* - split destination inode's inline extents. The inline extents can
* be either compressed or non-compressed.
*/
/* /*
* VFS's generic_remap_file_range_prep() protects us from cloning the * 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 * eof block into the middle of a file, which would result in corruption