From e001873853d87674dd5b3cfa2851885023616695 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 12 Mar 2013 23:30:34 +1100 Subject: [PATCH] xfs: ensure we capture IO errors correctly Failed buffer readahead can leave the buffer in the cache marked with an error. Most callers that then issue a subsequent read on the buffer do not zero the b_error field out, and so we may incorectly detect an error during IO completion due to the stale error value left on the buffer. Avoid this problem by zeroing the error before IO submission. This ensures that the only IO errors that are detected those captured from are those captured from bio submission or completion. Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers (cherry picked from commit c163f9a1760229a95d04e37b332de7d5c1c225cd) --- fs/xfs/xfs_buf.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 4e8f0df..8459b5d 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -1334,6 +1334,12 @@ _xfs_buf_ioapply( int size; int i; + /* + * Make sure we capture only current IO errors rather than stale errors + * left over from previous use of the buffer (e.g. failed readahead). + */ + bp->b_error = 0; + if (bp->b_flags & XBF_WRITE) { if (bp->b_flags & XBF_SYNCIO) rw = WRITE_SYNC; -- 2.7.4