ext4: ext4_mark_recovery_complete() doesn't need to use lock_super

The function ext4_mark_recovery_complete() is called from two call
paths: either (a) while mounting the filesystem, in which case there's
no danger of any other CPU calling write_super() until the mount is
completed, and (b) while remounting the filesystem read-write, in
which case the fs core has already locked the superblock.  This also
allows us to take out a very vile unlock_super()/lock_super() pair in
ext4_remount().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e3b35f2..45d0ada 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3219,13 +3219,11 @@ static void ext4_mark_recovery_complete(struct super_block *sb,
        if (jbd2_journal_flush(journal) < 0)
                goto out;
 
-       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);
                ext4_commit_super(sb, 1);
        }
-       unlock_super(sb);
 
 out:
        jbd2_journal_unlock_updates(journal);
@@ -3436,15 +3434,8 @@ 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.
-                        */
-                       if (sbi->s_journal) {
-                               unlock_super(sb);
+                       if (sbi->s_journal)
                                ext4_mark_recovery_complete(sb, es);
-                               lock_super(sb);
-                       }
                } else {
                        int ret;
                        if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,