Merge branch 'xfs-dio-extend-fix' into for-next

Conflicts:
	fs/xfs/xfs_file.c

diff --cc fs/xfs/xfs_file.c
index c203839cd5befc72325b4ddf9956b8272d926829,79ffb3e74f49edd052e7059c8af83303f425a288..3a5d305e60c9f505a71ec391b7af61f98d10e686
--- 1/fs/xfs/xfs_file.c
--- 2/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@@ -569,20 -565,39 +569,41 @@@ restart
         * write.  If zeroing is needed and we are currently holding the
         * iolock shared, we need to update it to exclusive which implies
         * having to redo all checks before.
+        *
+        * We need to serialise against EOF updates that occur in IO
+        * completions here. We want to make sure that nobody is changing the
+        * size while we do this check until we have placed an IO barrier (i.e.
+        * hold the XFS_IOLOCK_EXCL) that prevents new IO from being dispatched.
+        * The spinlock effectively forms a memory barrier once we have the
+        * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value
+        * and hence be able to correctly determine if we need to run zeroing.
         */
+       spin_lock(&ip->i_flags_lock);
        if (*pos > i_size_read(inode)) {
 +              bool    zero = false;
 +
+               spin_unlock(&ip->i_flags_lock);
                if (*iolock == XFS_IOLOCK_SHARED) {
                        xfs_rw_iunlock(ip, *iolock);
                        *iolock = XFS_IOLOCK_EXCL;
                        xfs_rw_ilock(ip, *iolock);
+ 
+                       /*
+                        * We now have an IO submission barrier in place, but
+                        * AIO can do EOF updates during IO completion and hence
+                        * we now need to wait for all of them to drain. Non-AIO
+                        * DIO will have drained before we are given the
+                        * XFS_IOLOCK_EXCL, and so for most cases this wait is a
+                        * no-op.
+                        */
+                       inode_dio_wait(inode);
                        goto restart;
                }
 -              error = xfs_zero_eof(ip, *pos, i_size_read(inode));
 +              error = xfs_zero_eof(ip, *pos, i_size_read(inode), &zero);
                if (error)
                        return error;
-       }
+       } else
+               spin_unlock(&ip->i_flags_lock);
  
        /*
         * Updating the timestamps will grab the ilock again from

diff --cc fs/xfs/xfs_trace.h
Simple merge