[XFS] Fix ABBA deadlock between i_mutex and iolock. Avoid calling

__blockdev_direct_IO for the DIO_OWN_LOCKING case for direct I/O reads
since it drops and reacquires the i_mutex while holding the iolock and
this violates the locking order.

SGI-PV: 955696
SGI-Modid: xfs-linux-melb:xfs-kern:26898a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chatterton <chatz@sgi.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index c40f81ba9b13..34dcb43a7837 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1390,11 +1390,19 @@ xfs_vm_direct_IO(
 
         iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);
 
-        ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
-                iomap.iomap_target->bt_bdev,
-                iov, offset, nr_segs,
-                xfs_get_blocks_direct,
-                xfs_end_io_direct);
+        if (rw == WRITE) {
+                ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
+                        iomap.iomap_target->bt_bdev,
+                        iov, offset, nr_segs,
+                        xfs_get_blocks_direct,
+                        xfs_end_io_direct);
+        } else {
+                ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
+                        iomap.iomap_target->bt_bdev,
+                        iov, offset, nr_segs,
+                        xfs_get_blocks_direct,
+                        xfs_end_io_direct);
+        }
 
         if (unlikely(ret <= 0 && iocb->private))
                 xfs_destroy_ioend(iocb->private);