2 files changed, 19 insertions, 0 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index fbc965fc075a..bd1a948ee39c 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -569,7 +569,9 @@ found:
          */
         if (bp->b_flags & XBF_STALE) {
                 ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
+                ASSERT(bp->b_iodone == NULL);
                 bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
+                bp->b_pre_io = NULL;
         }
 
         trace_xfs_buf_find(bp, flags, _RET_IP_);
@@ -1324,6 +1326,20 @@ _xfs_buf_ioapply(
         rw |= REQ_META;
 
         /*
+         * run the pre-io callback function if it exists. If this function
+         * fails it will mark the buffer with an error and the IO should
+         * not be dispatched.
+         */
+        if (bp->b_pre_io) {
+                bp->b_pre_io(bp);
+                if (bp->b_error) {
+                        xfs_force_shutdown(bp->b_target->bt_mount,
+                                           SHUTDOWN_CORRUPT_INCORE);
+                        return;
+                }
+        }
+
+        /*
          * Walk all the vectors issuing IO on them. Set up the initial offset
          * into the buffer and the desired IO size before we start -
          * _xfs_buf_ioapply_vec() will modify them appropriately for each
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 677b1dc822f4..51bc16a1cd9c 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -155,6 +155,9 @@ typedef struct xfs_buf {
         unsigned int            b_offset;       /* page offset in first page */
         unsigned short          b_error;        /* error code on I/O */
 
+        void                    (*b_pre_io)(struct xfs_buf *);
+                                                /* pre-io callback function */
+
 #ifdef XFS_BUF_LOCK_TRACKING
         int                     b_last_holder;
 #endif