3 files changed, 78 insertions, 17 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index e839907e8492..06149bac2f58 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -749,6 +749,30 @@ _xfs_buf_read(
 	return xfs_buf_submit(bp);
 }
 
+/*
+ * If the caller passed in an ops structure and the buffer doesn't have ops
+ * assigned, set the ops and use them to verify the contents.  If the contents
+ * cannot be verified, we'll clear XBF_DONE.  We assume the buffer has no
+ * recorded errors and is already in XBF_DONE state.
+ */
+int
+xfs_buf_ensure_ops(
+	struct xfs_buf		*bp,
+	const struct xfs_buf_ops *ops)
+{
+	ASSERT(bp->b_flags & XBF_DONE);
+	ASSERT(bp->b_error == 0);
+
+	if (!ops || bp->b_ops)
+		return 0;
+
+	bp->b_ops = ops;
+	bp->b_ops->verify_read(bp);
+	if (bp->b_error)
+		bp->b_flags &= ~XBF_DONE;
+	return bp->b_error;
+}
+
 xfs_buf_t *
 xfs_buf_read_map(
 	struct xfs_buftarg	*target,
@@ -762,26 +786,32 @@ xfs_buf_read_map(
 	flags |= XBF_READ;
 
 	bp = xfs_buf_get_map(target, map, nmaps, flags);
-	if (bp) {
-		trace_xfs_buf_read(bp, flags, _RET_IP_);
+	if (!bp)
+		return NULL;
 
-		if (!(bp->b_flags & XBF_DONE)) {
-			XFS_STATS_INC(target->bt_mount, xb_get_read);
-			bp->b_ops = ops;
-			_xfs_buf_read(bp, flags);
-		} else if (flags & XBF_ASYNC) {
-			/*
-			 * Read ahead call which is already satisfied,
-			 * drop the buffer
-			 */
-			xfs_buf_relse(bp);
-			return NULL;
-		} else {
-			/* We do not want read in the flags */
-			bp->b_flags &= ~XBF_READ;
-		}
+	trace_xfs_buf_read(bp, flags, _RET_IP_);
+
+	if (!(bp->b_flags & XBF_DONE)) {
+		XFS_STATS_INC(target->bt_mount, xb_get_read);
+		bp->b_ops = ops;
+		_xfs_buf_read(bp, flags);
+		return bp;
+	}
+
+	xfs_buf_ensure_ops(bp, ops);
+
+	if (flags & XBF_ASYNC) {
+		/*
+		 * Read ahead call which is already satisfied,
+		 * drop the buffer
+		 */
+		xfs_buf_relse(bp);
+		return NULL;
 	}
 
+	/* We do not want read in the flags */
+	bp->b_flags &= ~XBF_READ;
+	ASSERT(bp->b_ops != NULL || ops == NULL);
 	return bp;
 }
 
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 4e3171acd0f8..b9f5511ea998 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -385,4 +385,6 @@ extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int);
 #define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
 #define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)
 
+int xfs_buf_ensure_ops(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
+
 #endif	/* __XFS_BUF_H__ */
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 286a287ac57a..fc40160c1773 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -264,11 +264,39 @@ xfs_trans_read_buf_map(
 			return -EIO;
 		}
 
+		/*
+		 * Check if the caller is trying to read a buffer that is
+		 * already attached to the transaction yet has no buffer ops
+		 * assigned.  Ops are usually attached when the buffer is
+		 * attached to the transaction, or by the read caller if
+		 * special circumstances.  That didn't happen, which is not
+		 * how this is supposed to go.
+		 *
+		 * If the buffer passes verification we'll let this go, but if
+		 * not we have to shut down.  Let the transaction cleanup code
+		 * release this buffer when it kills the tranaction.
+		 */
+		ASSERT(bp->b_ops != NULL);
+		error = xfs_buf_ensure_ops(bp, ops);
+		if (error) {
+			xfs_buf_ioerror_alert(bp, __func__);
+
+			if (tp->t_flags & XFS_TRANS_DIRTY)
+				xfs_force_shutdown(tp->t_mountp,
+						SHUTDOWN_META_IO_ERROR);
+
+			/* bad CRC means corrupted metadata */
+			if (error == -EFSBADCRC)
+				error = -EFSCORRUPTED;
+			return error;
+		}
+
 		bip = bp->b_log_item;
 		bip->bli_recur++;
 
 		ASSERT(atomic_read(&bip->bli_refcount) > 0);
 		trace_xfs_trans_read_buf_recur(bip);
+		ASSERT(bp->b_ops != NULL || ops == NULL);
 		*bpp = bp;
 		return 0;
 	}
@@ -316,6 +344,7 @@ xfs_trans_read_buf_map(
 		_xfs_trans_bjoin(tp, bp, 1);
 		trace_xfs_trans_read_buf(bp->b_log_item);
 	}
+	ASSERT(bp->b_ops != NULL || ops == NULL);
 	*bpp = bp;
 	return 0;