[Ocfs2-devel] [PATCH V2] ocfs2: free up write context when direct IO failed

[Wengang Wang]

The write context should also be freed even when direct IO failed.
Otherwise a memory leak is introduced and entries remain in
oi->ip_unwritten_list causing the following BUG later in unlink path:

ERROR: bug expression: !list_empty(&oi->ip_unwritten_list)
ERROR: Clear inode of 215043, inode has unwritten extents
...
Call Trace:
? __set_current_blocked+0x42/0x68
ocfs2_evict_inode+0x91/0x6a0 [ocfs2]
? bit_waitqueue+0x40/0x33
evict+0xdb/0x1af
iput+0x1a2/0x1f7
do_unlinkat+0x194/0x28f
SyS_unlinkat+0x1b/0x2f
do_syscall_64+0x79/0x1ae
entry_SYSCALL_64_after_hwframe+0x151/0x0

This patch also logs, with frequency limit, direct IO failures.

Signed-off-by: Wengang Wang <wen.gang.wang at oracle.com>
---
v1 -> v2: log direct IO failures
---
 fs/ocfs2/aops.c            | 12 ++++++++++--
 fs/ocfs2/cluster/masklog.h |  9 +++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 302cd7c..7578bd5 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2412,8 +2412,16 @@ static int ocfs2_dio_end_io(struct kiocb *iocb,
 	/* this io's submitter should not have unlocked this before we could */
 	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
 
-	if (bytes > 0 && private)
-		ret = ocfs2_dio_end_io_write(inode, private, offset, bytes);
+	if (bytes <= 0)
+		mlog_ratelimited(ML_ERROR, "Direct IO failed, bytes = %lld",
+				 (long long)bytes);
+	if (private) {
+		if (bytes > 0)
+			ret = ocfs2_dio_end_io_write(inode, private, offset,
+						     bytes);
+		else
+			ocfs2_dio_free_write_ctx(inode, private);
+	}
 
 	ocfs2_iocb_clear_rw_locked(iocb);
 
diff --git a/fs/ocfs2/cluster/masklog.h b/fs/ocfs2/cluster/masklog.h
index 308ea0e..a396096 100644
--- a/fs/ocfs2/cluster/masklog.h
+++ b/fs/ocfs2/cluster/masklog.h
@@ -178,6 +178,15 @@ do {									\
 			      ##__VA_ARGS__);				\
 } while (0)
 
+#define mlog_ratelimited(mask, fmt, ...)				\
+do {									\
+	static DEFINE_RATELIMIT_STATE(_rs,				\
+				      DEFAULT_RATELIMIT_INTERVAL,	\
+				      DEFAULT_RATELIMIT_BURST);		\
+	if (__ratelimit(&_rs))						\
+		mlog(mask, fmt, ##__VA_ARGS__);				\
+} while (0)
+
 #define mlog_errno(st) ({						\
 	int _st = (st);							\
 	if (_st != -ERESTARTSYS && _st != -EINTR &&			\
-- 
2.9.5