From: Jan Kara Date: Mon, 16 Jul 2007 06:41:09 +0000 (-0700) Subject: ext4: fix deadlock in ext4_remount() and orphan list handling X-Git-Tag: v2.6.23-rc1~858 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=32c3773011a9b3522bd4abadc7fad8c27417119f;p=~shefty%2Frdma-dev.git 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 Cc: Eric Sandeen Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 6768c5aa3fe..bd9aff9701c 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,