Ocfs2 devel - Jul 2015 - [PATCH] ocfs2: do not BUG if buffer not uptodate in __ocfs2_journal_access

When storage network is unstable, it may trigger the BUG in
__ocfs2_journal_access because of buffer not uptodate. We can retry the
write in this case or return error instead of BUG.

Reported-by: Zhangguanghui <zhang.guanghui at h3c.com>
Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
---
 fs/ocfs2/journal.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index f8206d1..e731374 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -670,7 +670,23 @@ static int __ocfs2_journal_access(handle_t *handle,
 		mlog(ML_ERROR, "giving me a buffer that's not uptodate!\n");
 		mlog(ML_ERROR, "b_blocknr=%llu\n",
 		     (unsigned long long)bh->b_blocknr);
-		BUG();
+
+		lock_buffer(bh);
+		/*
+		 * A previous attempt to write this buffer head failed.
+		 * Nothing we can do but to retry the write and hope for
+		 * the best.
+		 */
+		if (buffer_write_io_error(bh) && !buffer_uptodate(bh)) {
+			clear_buffer_write_io_error(bh);
+			set_buffer_uptodate(bh);
+		}
+
+		if (!buffer_uptodate(bh)) {
+			unlock_buffer(bh);
+			return -EIO;
+		}
+		unlock_buffer(bh);
 	}

 	/* Set the current transaction information on the ci so
-- 
1.8.4.3

This patch is currently verified and working well for two weeks.
So it is reasonable for the case.

Finally, any feedback about this process (positive or negative) would be greatly
appreciated.
________________________________
zhangguanghui

From: Joseph Qi<mailto:joseph.qi at huawei.com>
Date: 2015-07-06 10:05
To: Andrew Morton<mailto:akpm at linux-foundation.org>
CC: Mark Fasheh<mailto:mfasheh at suse.com>; Joel Becker<mailto:jlbec
at evilplan.org>; zhangguanghui 10102 (CCPL)<mailto:zhang.guanghui at
h3c.com>; ocfs2-devel at oss.oracle.com<mailto:ocfs2-devel at
oss.oracle.com>
Subject: [PATCH] ocfs2: do not BUG if buffer not uptodate in
__ocfs2_journal_access

When storage network is unstable, it may trigger the BUG in
__ocfs2_journal_access because of buffer not uptodate. We can retry the
write in this case or return error instead of BUG.

Reported-by: Zhangguanghui <zhang.guanghui at h3c.com>
Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
---
 fs/ocfs2/journal.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index f8206d1..e731374 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -670,7 +670,23 @@ static int __ocfs2_journal_access(handle_t *handle,
                mlog(ML_ERROR, "giving me a buffer that's not
uptodate!\n");
                mlog(ML_ERROR, "b_blocknr=%llu\n",
                     (unsigned long long)bh->b_blocknr);
-               BUG();
+
+               lock_buffer(bh);
+               /*
+                * A previous attempt to write this buffer head failed.
+                * Nothing we can do but to retry the write and hope for
+                * the best.
+                */
+               if (buffer_write_io_error(bh) && !buffer_uptodate(bh)) {
+                       clear_buffer_write_io_error(bh);
+                       set_buffer_uptodate(bh);
+               }
+
+               if (!buffer_uptodate(bh)) {
+                       unlock_buffer(bh);
+                       return -EIO;
+               }
+               unlock_buffer(bh);
        }

        /* Set the current transaction information on the ci so
--
1.8.4.3



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