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ext4: fix possible tid_t sequence overflows

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In the fast commit code there are a few places where tid_t variables are
being compared without taking into account the fact that these sequence
numbers may wrap.  Fix this issue by using the helper functions tid_gt()
and tid_geq().

Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://patch.msgid.link/20240529092030.9557-3-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Luis Henriques (SUSE) 2024-05-29 10:20:30 +01:00 committed by Theodore Ts'o
parent 2d4d6bda0f
commit 63469662cc
1 changed files with 4 additions and 4 deletions
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8
fs/ext4/fast_commit.c
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@ -353,7 +353,7 @@ void ext4_fc_mark_ineligible(struct super_block *sb, int reason, handle_t *handl
read_unlock(&sbi->s_journal->j_state_lock);
}
spin_lock(&sbi->s_fc_lock);
if (sbi->s_fc_ineligible_tid < tid)
if (tid_gt(tid, sbi->s_fc_ineligible_tid))
sbi->s_fc_ineligible_tid = tid;
spin_unlock(&sbi->s_fc_lock);
WARN_ON(reason >= EXT4_FC_REASON_MAX);
@ -1207,7 +1207,7 @@ restart_fc:
if (ret == -EALREADY) {
/* There was an ongoing commit, check if we need to restart */
if (atomic_read(&sbi->s_fc_subtid) <= subtid &&
commit_tid > journal->j_commit_sequence)
tid_gt(commit_tid, journal->j_commit_sequence))
goto restart_fc;
ext4_fc_update_stats(sb, EXT4_FC_STATUS_SKIPPED, 0, 0,
commit_tid);
@ -1282,7 +1282,7 @@ static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
list_del_init(&iter->i_fc_list);
ext4_clear_inode_state(&iter->vfs_inode,
EXT4_STATE_FC_COMMITTING);
if (iter->i_sync_tid <= tid)
if (tid_geq(tid, iter->i_sync_tid))
ext4_fc_reset_inode(&iter->vfs_inode);
/* Make sure EXT4_STATE_FC_COMMITTING bit is clear */
smp_mb();
@ -1313,7 +1313,7 @@ static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
list_splice_init(&sbi->s_fc_q[FC_Q_STAGING],
&sbi->s_fc_q[FC_Q_MAIN]);
if (tid >= sbi->s_fc_ineligible_tid) {
if (tid_geq(tid, sbi->s_fc_ineligible_tid)) {
sbi->s_fc_ineligible_tid = 0;
ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
}