xfs: uncached buffer reads need to return an error

With verification being done as an IO completion callback, different
errors can be returned from a read. Uncached reads only return a
buffer or NULL on failure, which means the verification error cannot
be returned to the caller.

Split the error handling for these reads into two - a failure to get
a buffer will still return NULL, but a read error will return a
referenced buffer with b_error set rather than NULL. The caller is
responsible for checking the error state of the buffer returned.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 2 insertions, 7 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 0298dd68479..fbc965fc075 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -715,8 +715,7 @@ xfs_buf_read_uncached(
         int                     flags,
         xfs_buf_iodone_t        verify)
 {
-        xfs_buf_t               *bp;
-        int                     error;
+        struct xfs_buf          *bp;
 
         bp = xfs_buf_get_uncached(target, numblks, flags);
         if (!bp)
@@ -730,11 +729,7 @@ xfs_buf_read_uncached(
         bp->b_iodone = verify;
 
         xfsbdstrat(target->bt_mount, bp);
-        error = xfs_buf_iowait(bp);
-        if (error) {
-                xfs_buf_relse(bp);
-                return NULL;
-        }
+        xfs_buf_iowait(bp);
         return bp;
 }