CVE-2026-89830

In the Linux kernel, the following vulnerability has been resolved:

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.