Merge tag 'xfs-for-linus-4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull more xfs updates from Dave Chinner:
 "This is the second update for XFS that I mentioned in the original
  pull request last week.

  It contains a revert for a suspend regression in 4.4 and a fix for a
  long standing log recovery issue that has been further exposed by all
  the log recovery changes made in the original 4.5 merge.

  There is one more thing in this pull request - one that I forgot to
  merge into the origin.  That is, pulling the XFS_IOC_FS[GS]ETXATTR
  ioctl up to the VFS level so that other filesystems can also use it
  for modifying project quota IDs

  Summary:

   - promotion of XFS_IOC_FS[GS]ETXATTR ioctl to the vfs level so that
     it can be shared with other filesystems.  The ext4 project quota
     functionality is the first target for this.  The commits in this
     series have not been updated with review or final SOB tags because
     the branch they were originally published in was needed by ext4.
     Those tags are:

        Reviewed-by: Theodore Ts'o <tytso@mit.edu>
        Signed-off-by: Dave Chinner <david@fromrobit.com>

   - Revert a change that is causing suspend failures.

   - Fix a use-after-free that can occur on log mount failures.  Been
     around forever, but now exposed by other changes to log recovery
     made in the first 4.5 merge"

* tag 'xfs-for-linus-4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: log mount failures don't wait for buffers to be released
  Revert "xfs: clear PF_NOFREEZE for xfsaild kthread"
  xfs: introduce per-inode DAX enablement
  xfs: use FS_XFLAG definitions directly
  fs: XFS_IOC_FS[SG]SETXATTR to FS_IOC_FS[SG]ETXATTR promotion

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index daed4bfb85b2..435c7de42e5f 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1527,6 +1527,16 @@ xfs_wait_buftarg(
 	LIST_HEAD(dispose);
 	int loop = 0;
 
+	/*
+	 * We need to flush the buffer workqueue to ensure that all IO
+	 * completion processing is 100% done. Just waiting on buffer locks is
+	 * not sufficient for async IO as the reference count held over IO is
+	 * not released until after the buffer lock is dropped. Hence we need to
+	 * ensure here that all reference counts have been dropped before we
+	 * start walking the LRU list.
+	 */
+	drain_workqueue(btp->bt_mount->m_buf_workqueue);
+
 	/* loop until there is nothing left on the lru list. */
 	while (list_lru_count(&btp->bt_lru)) {
 		list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele,