=============
22a5672 ext4: online defrag is not supported for journaled files
ba57d9e ext4: move_extent code cleanup
   No behavioral change unless e4defrag has been used.

Online Resize
=============
5018ddd ext4: avoid duplicate writes of the backup bg descriptor blocks
256ae46 ext4: don't copy non-existent gdt blocks when resizing
416a688 ext4: ignore last group w/o enough space when resizing instead of BUG'ing
   No observable change unless online resizing (e2resize) has been used

Other Commits
=============
92b7722 ext4: fix mtime update in nodelalloc mode
   Changes where we call file_update_time()

34414b2 ext4: fix fdatasync() for files with only i_size changes
   Forces the inode changes to be commited if only i_sync changes when
   fdatasync() is called.  No changes except performance impact
   to fdatasync() and correctness after a system crash.

12ebdf0 ext4: always set i_op in ext4_mknod()
   Fixes a bug if CONFIG_EXT4_FS_XATTR is not defined;
   no change if CONFIG_EXT4_FS_XATTR is defined

2fdb112 ext4: fix crash when accessing /proc/mounts concurrently
   Remove an erroneous "static" for an function so it is allocated on the stack;
   fixes a bug if two processes cat /proc/mounts at the same time

1638f1f ext4: fix potential deadlock in ext4_nonda_switch()
   Fixes a circular lock dependency

14b4ed2 jbd2: don't write superblock when if its empty
   If journal->s_start is zero, we may not update journal->s_sequence when
   it might be needed.  (But we at the moement we can't see how this could
   lead to the reported fs corruptions.)


commit cb57108637e01ec2f02d9311cedc3013e96f25d4
Author: Theodore Ts'o <tytso@mit.edu>
Date:   Wed Oct 24 01:01:41 2012 -0400

    jbd2: fix a potential fs corrupting bug in jbd2_mark_journal_empty
    
    Fix a potential file system corrupting bug which was introduced by
    commit eeecef0af5ea4efd763c9554cf2bd80fc4a0efd3: jbd2: don't write
    superblock when if its empty.
    
    We should only skip writing the journal superblock if there is nothing
    to do --- not just when s_start is zero.
    
    This has caused users to report file system corruptions in ext4 that
    look like this:
    
    EXT4-fs error (device sdb3): ext4_mb_generate_buddy:741: group 436, 22902 clusters in bitmap, 22901 in gd
    JBD2: Spotted dirty metadata buffer (dev = sdb3, blocknr = 0). There's a risk of filesystem corruption in case of system crash.
    
    after the file system has been corrupted.
    
    Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
    Cc: stable@vger.kernel.org

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0f16edd..26b2983 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1351,24 +1351,33 @@ void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
 static void jbd2_mark_journal_empty(journal_t *journal)
 {
 	journal_superblock_t *sb = journal->j_superblock;
+	__be32		new_tail_sequence;
 
 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
 	read_lock(&journal->j_state_lock);
-	/* Is it already empty? */
+	new_tail_sequence = cpu_to_be32(journal->j_tail_sequence);
+	/* Nothing to do? */
 	if (sb->s_start == 0) {
+		pr_err("JBD2: jbd2_mark_journal_empty bug workaround (%u, %u)\n",
+		       (unsigned) be32_to_cpu(sb->s_sequence),
+		       (unsigned) be32_to_cpu(new_tail_sequence));
+		WARN_ON(1);
+	}
+	if (sb->s_start == 0 && sb->s_sequence == new_tail_sequence) {
 		read_unlock(&journal->j_state_lock);
-		return;
+		goto set_flushed;
 	}
 	jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
 		  journal->j_tail_sequence);
 
-	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
+	sb->s_sequence = new_tail_sequence;
 	sb->s_start    = cpu_to_be32(0);
 	read_unlock(&journal->j_state_lock);
 
 	jbd2_write_superblock(journal, WRITE_FUA);
 
-	/* Log is no longer empty */
+set_flushed:
+	/* Log is empty */
 	write_lock(&journal->j_state_lock);
 	journal->j_flags |= JBD2_FLUSHED;
 	write_unlock(&journal->j_state_lock);