CVE-2024-49959

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

jbd2: stop waiting for space when jbd2_cleanup_journal_tail() returns error

In __jbd2_log_wait_for_space(), we might call jbd2_cleanup_journal_tail()
to recover some journal space. But if an error occurs while executing
jbd2_cleanup_journal_tail() (e.g., an EIO), we don't stop waiting for free
space right away, we try other branches, and if j_committing_transaction
is NULL (i.e., the tid is 0), we will get the following complain:

============================================
JBD2: I/O error when updating journal superblock for sdd-8.
__jbd2_log_wait_for_space: needed 256 blocks and only had 217 space available
__jbd2_log_wait_for_space: no way to get more journal space in sdd-8
------------[ cut here ]------------
WARNING: CPU: 2 PID: 139804 at fs/jbd2/checkpoint.c:109 __jbd2_log_wait_for_space+0x251/0x2e0
Modules linked in:
CPU: 2 PID: 139804 Comm: kworker/u8:3 Not tainted 6.6.0+ #1
RIP: 0010:__jbd2_log_wait_for_space+0x251/0x2e0
Call Trace:
<TASK>
add_transaction_credits+0x5d1/0x5e0
start_this_handle+0x1ef/0x6a0
jbd2__journal_start+0x18b/0x340
ext4_dirty_inode+0x5d/0xb0
__mark_inode_dirty+0xe4/0x5d0
generic_update_time+0x60/0x70
[...]
============================================

So only if jbd2_cleanup_journal_tail() returns 1, i.e., there is nothing to
clean up at the moment, continue to try to reclaim free space in other ways.

Note that this fix relies on commit 6f6a6fda2945 ("jbd2: fix ocfs2 corrupt
when updating journal superblock fails") to make jbd2_cleanup_journal_tail
return the correct error code.