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authorJan Kara <jack@suse.cz>2007-07-16 10:41:09 +0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 20:05:48 +0400
commit32c3773011a9b3522bd4abadc7fad8c27417119f (patch)
treec3a07aecbef3cdb66a4126e2822c69166aee1c97 /fs/ext4
parent030703e49d4966bd348660e0fdc2699507efb82b (diff)
downloadlinux-32c3773011a9b3522bd4abadc7fad8c27417119f.tar.xz
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: Jan Kara <jack@suse.cz> Cc: Eric Sandeen <sandeen@sandeen.net> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/super.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6768c5aa3fee..bd9aff9701c0 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2222,12 +2222,14 @@ static void ext4_mark_recovery_complete(struct super_block * sb,
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_block * sb, int * flags, char * data)
(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,