2007-06-12 21:03:39

by Andrew Morton

[permalink] [raw]
Subject: + ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling.patch added to -mm tree


The patch titled
ext3: fix deadlock in ext3_remount() and orphan list handling
has been added to the -mm tree. Its filename is
ext3-fix-deadlock-in-ext3_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: ext3: fix deadlock in ext3_remount() and orphan list handling
From: Jan Kara <[email protected]>

ext3_orphan_add() and ext3_orphan_del() functions lock sb->s_lock with a
transaction started with ext3_mark_recovery_complete() waits for a transaction
holding sb->s_lock, thus leading to a possible deadlock. At the moment we
call ext3_mark_recovery_complete() from ext3_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 <[email protected]>
Cc: Eric Sandeen <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

fs/ext3/super.c | 8 ++++++++
1 files changed, 8 insertions(+)

diff -puN fs/ext3/super.c~ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling fs/ext3/super.c
--- a/fs/ext3/super.c~ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling
+++ a/fs/ext3/super.c
@@ -2147,12 +2147,14 @@ static void ext3_mark_recovery_complete(

journal_lock_updates(journal);
journal_flush(journal);
+ lock_super(sb);
if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER) &&
sb->s_flags & MS_RDONLY) {
EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
sb->s_dirt = 0;
ext3_commit_super(sb, es, 1);
}
+ unlock_super(sb);
journal_unlock_updates(journal);
}

@@ -2341,7 +2343,13 @@ static int ext3_remount (struct super_bl
(sbi->s_mount_state & EXT3_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);
ext3_mark_recovery_complete(sb, es);
+ lock_super(sb);
} else {
__le32 ret;
if ((ret = EXT3_HAS_RO_COMPAT_FEATURE(sb,
_

Patches currently in -mm which might be from [email protected] 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