The patch titled
ext4: fix deadlock in ext4_remount() and orphan list handling
has been added to the -mm tree. Its filename is
ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: ext4: fix deadlock in ext4_remount() and orphan list handling
From: Jan Kara <jack@xxxxxxx>
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: Jan Kara <jack@xxxxxxx>
Cc: Eric Sandeen <sandeen@xxxxxxxxxxx>
Cc: <linux-ext4@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ext4/super.c | 8 ++++++++
1 files changed, 8 insertions(+)
diff -puN fs/ext4/super.c~ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling fs/ext4/super.c
--- a/fs/ext4/super.c~ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling
+++ a/fs/ext4/super.c
@@ -2222,12 +2222,14 @@ static void ext4_mark_recovery_complete(
jbd2_journal_lock_updates(journal);
jbd2_journal_flush(journal);
+ lock_super(sb);
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
sb->s_flags & MS_RDONLY) {
EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
sb->s_dirt = 0;
ext4_commit_super(sb, es, 1);
}
+ unlock_super(sb);
jbd2_journal_unlock_updates(journal);
}
@@ -2416,7 +2418,13 @@ static int ext4_remount (struct super_bl
(sbi->s_mount_state & EXT4_VALID_FS))
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);
+ lock_super(sb);
} else {
__le32 ret;
if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,
_
Patches currently in -mm which might be from jack@xxxxxxx are
udf-fix-possible-leakage-of-blocks.patch
udf-fix-possible-leakage-of-blocks-fix.patch
ext2-fix-a-comment-when-ext2_release_file-is-called.patch
ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling.patch
ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling.patch
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