f2fs: fix valid block count leak on data block allocation failure

In __allocate_data_block(), when allocating a new data block
(dn->data_blkaddr == NULL_ADDR), inc_valid_block_count() is
called first to increment total_valid_block_count and i_blocks.
If the subsequent f2fs_allocate_data_block() fails, the function
returns the error directly without rolling back the
already-incremented block counts, causing a permanent leak.

Fix this by calling dec_valid_block_count() to undo the
increment before returning the error. The condition
old_blkaddr == NULL_ADDR precisely identifies the case where
inc_valid_block_count() was called.

Fixes: 7d009e048d7c ("f2fs: fix to handle segment allocation failure correctly")
Cc: <stable@vger.kernel.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Chen Changcheng <chenchangcheng@kylinos.cn>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

0 files changed, 0 insertions, 0 deletions