When using lvconvert to convert a linear mapping to a dm-raid1 mirror,
we encountered issues where the log would be flooded with messages like:
metadata I/O error: block 0xee7060 ("xfs_trans_read_buf") error 11 numblks 8
The cause is that dm-mirror (and striping, and others) will return
-EWOULDBLOCK for readahead requests while the mirror is rebuilding. XFS's
end_io routine caches the errno and then xfs_buf_iowait bails out early
when it encounters it after issuing the i/o request. The I/O eventually
succeeds and the endio routine resets bp->b_error, but the original read
request has already returned -EWOULDBLOCK to the user and added the log
message above to the kernel log, freaking everyone out.
This patch ignores EWOULDBLOCK when deciding whether to wait for the I/O
to complete and tries again, allowing the read to succeed as expected.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Reviewed-by: Rich Johnston <rjohnston@xxxxxxx>
---
fs/xfs/xfs_buf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1252,7 +1252,7 @@ xfs_buf_iowait(
{
trace_xfs_buf_iowait(bp, _RET_IP_);
- if (!bp->b_error)
+ if (!bp->b_error || bp->b_error == EWOULDBLOCK)
wait_for_completion(&bp->b_iowait);
trace_xfs_buf_iowait_done(bp, _RET_IP_);
--
Jeff Mahoney
SUSE Labs
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