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, 6 insertions, 0 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index d5402b0eb6a3..df6d0b2aade1 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -658,6 +658,12 @@ reread:
                         xfs_warn(mp, "SB buffer read failed");
                 return EIO;
         }
+        if (bp->b_error) {
+                error = bp->b_error;
+                if (loud)
+                        xfs_warn(mp, "SB validate failed");
+                goto release_buf;
+        }
 
         /*
          * Initialize the mount structure from the superblock.