Commit 32c37730 authored by Jan Kara's avatar Jan Kara Committed by Linus Torvalds

ext4: fix deadlock in ext4_remount() and orphan list handling

ext4_orphan_add() and ext4_orphan_del() functions lock sb->s_lock with a
transaction started with ext4_mark_recovery_complete() waits for a transaction
holding sb->s_lock, thus leading to a possible deadlock.  At the moment we
call ext4_mark_recovery_complete() from ext4_remount() we have done all the
work needed for remounting and thus we are safe to drop sb->s_lock before we
wait for transactions to commit.  Note that at this moment we are still
guarded by s_umount lock against other remounts/umounts.
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Cc: Eric Sandeen <sandeen@sandeen.net>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 030703e4
...@@ -2222,12 +2222,14 @@ static void ext4_mark_recovery_complete(struct super_block * sb, ...@@ -2222,12 +2222,14 @@ static void ext4_mark_recovery_complete(struct super_block * sb,
jbd2_journal_lock_updates(journal); jbd2_journal_lock_updates(journal);
jbd2_journal_flush(journal); jbd2_journal_flush(journal);
lock_super(sb);
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) && if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
sb->s_flags & MS_RDONLY) { sb->s_flags & MS_RDONLY) {
EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER); EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
sb->s_dirt = 0; sb->s_dirt = 0;
ext4_commit_super(sb, es, 1); ext4_commit_super(sb, es, 1);
} }
unlock_super(sb);
jbd2_journal_unlock_updates(journal); jbd2_journal_unlock_updates(journal);
} }
...@@ -2416,7 +2418,13 @@ static int ext4_remount (struct super_block * sb, int * flags, char * data) ...@@ -2416,7 +2418,13 @@ static int ext4_remount (struct super_block * sb, int * flags, char * data)
(sbi->s_mount_state & EXT4_VALID_FS)) (sbi->s_mount_state & EXT4_VALID_FS))
es->s_state = cpu_to_le16(sbi->s_mount_state); es->s_state = cpu_to_le16(sbi->s_mount_state);
/*
* We have to unlock super so that we can wait for
* transactions.
*/
unlock_super(sb);
ext4_mark_recovery_complete(sb, es); ext4_mark_recovery_complete(sb, es);
lock_super(sb);
} else { } else {
__le32 ret; __le32 ret;
if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb, if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,
......
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