Re: [PATCH] fix barrier fail detection

Timothy Shimmin
2008-10-10T04:15:33Z

Timothy Shimmin wrote:
> Christoph Hellwig wrote:
>> Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_buf.c
>> ===================================================================
>> --- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_buf.c 2008-10-09 13:36:50.000000000 +0200
>> +++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_buf.c 2008-10-09 13:38:38.000000000 +0200
>> @@ -1007,6 +1007,7 @@ xfs_buf_iodone_work(
>> (bp->b_flags & (XBF_ORDERED|XBF_ASYNC)) == (XBF_ORDERED|XBF_ASYNC)) {
>> XB_TRACE(bp, "ordered_retry", bp->b_iodone);
>> bp->b_flags &= ~XBF_ORDERED;
>> + bp->b_flags |= _XFS_BARRIER_FAILED;
>> xfs_buf_iorequest(bp);
>> } else if (bp->b_iodone)
>> (*(bp->b_iodone))(bp);
>
> Actually, probably need to update the comment for this one.
>

>> Index: linux-2.6-xfs/fs/xfs/xfs_log.c
>> ===================================================================
>> --- linux-2.6-xfs.orig/fs/xfs/xfs_log.c 2008-10-09 13:38:44.000000000 +0200
>> +++ linux-2.6-xfs/fs/xfs/xfs_log.c 2008-10-09 13:39:32.000000000 +0200
>> @@ -1037,7 +1037,8 @@ xlog_iodone(xfs_buf_t *bp)
>> * layer, it means the underlyin device no longer supports
>> * barrier I/O. Warn loudly and turn off barriers.
>> */
>> - if ((l->l_mp->m_flags & XFS_MOUNT_BARRIER) && !XFS_BUF_ISORDERED(bp)) {
>> + if (bp->b_flags & _XFS_BARRIER_FAILED) {
>> + bp->b_flags &= ~_XFS_BARRIER_FAILED;
>> l->l_mp->m_flags &= ~XFS_MOUNT_BARRIER;
>> xfs_fs_cmn_err(CE_WARN, l->l_mp,
>> "xlog_iodone: Barriers are no longer supported"
>>
> Okay, we probably should update this comment too.
>
> Might as well fix the existing typo "underlyin" in the comment as well :)
> Thanks,
> --Tim
>

i.e. something like:

Index: 2.6.x-xfs-quilt/fs/xfs/linux-2.6/xfs_buf.c
===================================================================
--- 2.6.x-xfs-quilt.orig/fs/xfs/linux-2.6/xfs_buf.c 2008-09-19 13:47:36.000000000 +1000
+++ 2.6.x-xfs-quilt/fs/xfs/linux-2.6/xfs_buf.c 2008-10-10 15:07:51.316145158 +1100
@@ -1001,12 +1001,13 @@ xfs_buf_iodone_work(
* We can get an EOPNOTSUPP to ordered writes. Here we clear the
* ordered flag and reissue them. Because we can't tell the higher
* layers directly that they should not issue ordered I/O anymore, they
- * need to check if the ordered flag was cleared during I/O completion.
+ * need to check if the _XFS_BARRIER_FAILED flag was set during I/O completion.
*/
if ((bp->b_error == EOPNOTSUPP) &&
(bp->b_flags & (XBF_ORDERED|XBF_ASYNC)) == (XBF_ORDERED|XBF_ASYNC)) {
XB_TRACE(bp, "ordered_retry", bp->b_iodone);
bp->b_flags &= ~XBF_ORDERED;
+ bp->b_flags |= _XFS_BARRIER_FAILED;
xfs_buf_iorequest(bp);
} else if (bp->b_iodone)
(*(bp->b_iodone))(bp);
Index: 2.6.x-xfs-quilt/fs/xfs/linux-2.6/xfs_buf.h
===================================================================
--- 2.6.x-xfs-quilt.orig/fs/xfs/linux-2.6/xfs_buf.h 2008-09-19 13:47:36.000000000 +1000
+++ 2.6.x-xfs-quilt/fs/xfs/linux-2.6/xfs_buf.h 2008-10-10 11:54:23.269373217 +1100
@@ -85,6 +85,14 @@ typedef enum {
* modifications being lost.
*/
_XBF_PAGE_LOCKED = (1 << 22),
+
+ /*
+ * If we try a barrier write, but it fails we have to communicate
+ * this to the upper layers. Unfortunately b_error gets overwritten
+ * when the buffer is re-issued so we have to add another flag to
+ * keep this information.
+ */
+ _XFS_BARRIER_FAILED = (1 << 23),
} xfs_buf_flags_t;

typedef enum {
Index: 2.6.x-xfs-quilt/fs/xfs/xfs_log.c
===================================================================
--- 2.6.x-xfs-quilt.orig/fs/xfs/xfs_log.c 2008-09-22 11:54:19.000000000 +1000
+++ 2.6.x-xfs-quilt/fs/xfs/xfs_log.c 2008-10-10 15:09:56.967725107 +1100
@@ -1033,11 +1033,12 @@ xlog_iodone(xfs_buf_t *bp)
l = iclog->ic_log;

/*
- * If the ordered flag has been removed by a lower
- * layer, it means the underlyin device no longer supports
+ * If the _XFS_BARRIER_FAILED flag was set by a lower
+ * layer, it means the underlying device no longer supports
* barrier I/O. Warn loudly and turn off barriers.
*/
- if ((l->l_mp->m_flags & XFS_MOUNT_BARRIER) && !XFS_BUF_ISORDERED(bp)) {
+ if (bp->b_flags & _XFS_BARRIER_FAILED) {
+ bp->b_flags &= ~_XFS_BARRIER_FAILED;
l->l_mp->m_flags &= ~XFS_MOUNT_BARRIER;
xfs_fs_cmn_err(CE_WARN, l->l_mp,
"xlog_iodone: Barriers are no longer supported"