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btrfs: track qgroup released data in own variable in insert_prealloc_file_extent

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There is a piece of weird code in insert_prealloc_file_extent(), which
looks like:

	ret = btrfs_qgroup_release_data(inode, file_offset, len);
	if (ret < 0)
		return ERR_PTR(ret);
	if (trans) {
		ret = insert_reserved_file_extent(trans, inode,
						  file_offset, &stack_fi,
						  true, ret);
	...
	}
	extent_info.is_new_extent = true;
	extent_info.qgroup_reserved = ret;
	...

Note how the variable @ret is abused here, and if anyone is adding code
just after btrfs_qgroup_release_data() call, it's super easy to
overwrite the @ret and cause tons of qgroup related bugs.

Fix such abuse by introducing new variable @qgroup_released, so that we
won't reuse the existing variable @ret.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2021-03-03 18:41:51 +08:00 committed by David Sterba
parent d2dcc8ed8e
commit fbf48bb0b1
1 changed files with 6 additions and 5 deletions
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11
fs/btrfs/inode.c
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@ -9873,6 +9873,7 @@ static struct btrfs_trans_handle *insert_prealloc_file_extent(
struct btrfs_path *path;
u64 start = ins->objectid;
u64 len = ins->offset;
int qgroup_released;
int ret;
memset(&stack_fi, 0, sizeof(stack_fi));
@ -9885,14 +9886,14 @@ static struct btrfs_trans_handle *insert_prealloc_file_extent(
btrfs_set_stack_file_extent_compression(&stack_fi, BTRFS_COMPRESS_NONE);
/* Encryption and other encoding is reserved and all 0 */
ret = btrfs_qgroup_release_data(inode, file_offset, len);
if (ret < 0)
return ERR_PTR(ret);
qgroup_released = btrfs_qgroup_release_data(inode, file_offset, len);
if (qgroup_released < 0)
return ERR_PTR(qgroup_released);
if (trans) {
ret = insert_reserved_file_extent(trans, inode,
file_offset, &stack_fi,
true, ret);
true, qgroup_released);
if (ret)
return ERR_PTR(ret);
return trans;
@ -9905,7 +9906,7 @@ static struct btrfs_trans_handle *insert_prealloc_file_extent(
extent_info.file_offset = file_offset;
extent_info.extent_buf = (char *)&stack_fi;
extent_info.is_new_extent = true;
extent_info.qgroup_reserved = ret;
extent_info.qgroup_reserved = qgroup_released;
extent_info.insertions = 0;
path = btrfs_alloc_path();