CVE-2024-47669

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

nilfs2: fix state management in error path of log writing function

After commit a694291a6211 ("nilfs2: separate wait function from nilfssegctorwrite") was applied, the log writing function nilfssegctordo_construct() was able to issue I/O requests continuously even if user data blocks were split into multiple logs across segments, but two potential flaws were introduced in its error handling.

First, if nilfssegctorbeginconstruction() fails while creating the second or subsequent logs, the log writing function returns without calling nilfssegctorabortconstruction(), so the writeback flag set on pages/folios will remain uncleared. This causes page cache operations to hang waiting for the writeback flag. For example, truncateinodepagesfinal(), which is called via nilfsevict_inode() when an inode is evicted from memory, will hang.

Second, the NILFSICOLLECTED flag set on normal inodes remain uncleared. As a result, if the next log write involves checkpoint creation, that's fine, but if a partial log write is performed that does not, inodes with NILFSICOLLECTED set are erroneously removed from the "scdirtyfiles" list, and their data and b-tree blocks may not be written to the device, corrupting the block mapping.

Fix these issues by uniformly calling nilfssegctorabortconstruction() on failure of each step in the loop in nilfssegctordoconstruct(), having it clean up logs and segment usages according to progress, and correcting the conditions for calling nilfsredirtyinodes() to ensure that the NILFSICOLLECTED flag is cleared.