xfs: check xfs_buf_read_uncached returns correctly

xfs_buf_read_uncached() has two failure modes. If can either return
NULL or bp->b_error != 0 depending on the type of failure, and not
all callers check for both. Fix it so that xfs_buf_read_uncached()
always returns the error status, and the buffer is returned as a
function parameter. The buffer will only be returned on success.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index d99ec83..6fbcbbf 100644 (file)
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -688,29 +688,39 @@ xfs_buf_readahead_map(
  * Read an uncached buffer from disk. Allocates and returns a locked
  * buffer containing the disk contents or nothing.
  */
-struct xfs_buf *
+int
 xfs_buf_read_uncached(
        struct xfs_buftarg      *target,
        xfs_daddr_t             daddr,
        size_t                  numblks,
        int                     flags,
+       struct xfs_buf          **bpp,
        const struct xfs_buf_ops *ops)
 {
        struct xfs_buf          *bp;
 
+       *bpp = NULL;
+
        bp = xfs_buf_get_uncached(target, numblks, flags);
        if (!bp)
-               return NULL;
+               return -ENOMEM;
 
        /* set up the buffer for a read IO */
        ASSERT(bp->b_map_count == 1);
-       bp->b_bn = daddr;
+       bp->b_bn = XFS_BUF_DADDR_NULL;  /* always null for uncached buffers */
        bp->b_maps[0].bm_bn = daddr;
        bp->b_flags |= XBF_READ;
        bp->b_ops = ops;
 
        xfs_buf_submit_wait(bp);
-       return bp;
+       if (bp->b_error) {
+               int     error = bp->b_error;
+               xfs_buf_relse(bp);
+               return error;
+       }
+
+       *bpp = bp;
+       return 0;
 }
 
 /*

diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 0acfc30..82002c0 100644 (file)
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -269,9 +269,9 @@ int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
 
 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
                                int flags);
-struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
-                               xfs_daddr_t daddr, size_t numblks, int flags,
-                               const struct xfs_buf_ops *ops);
+int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
+                         size_t numblks, int flags, struct xfs_buf **bpp,
+                         const struct xfs_buf_ops *ops);
 void xfs_buf_hold(struct xfs_buf *bp);
 
 /* Releasing Buffers */

diff --cc fs/xfs/xfs_fsops.c
Simple merge

diff --cc fs/xfs/xfs_mount.c
Simple merge

diff --cc fs/xfs/xfs_rtalloc.c
Simple merge