linux-kernel - [PATCH 4.19 102/205] ocfs2: free up write context when direct IO failed

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Date:   Mon, 19 Nov 2018 17:26:49 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Wengang Wang <wen.gang.wang@...cle.com>,
        Junxiao Bi <junxiao.bi@...cle.com>,
        Changwei Ge <ge.changwei@....com>,
        Joseph Qi <jiangqi903@...il.com>,
        Mark Fasheh <mark@...heh.com>,
        Joel Becker <jlbec@...lplan.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.19 102/205] ocfs2: free up write context when direct IO failed

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wengang Wang <wen.gang.wang@...cle.com>

commit 5040f8df56fb90c7919f1c9b0b6e54c843437456 upstream.

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.

Link: http://lkml.kernel.org/r/20181102170632.25921-1-wen.gang.wang@oracle.com
Signed-off-by: Wengang Wang <wen.gang.wang@...cle.com>
Reviewed-by: Junxiao Bi <junxiao.bi@...cle.com>
Reviewed-by: Changwei Ge <ge.changwei@....com>
Reviewed-by: Joseph Qi <jiangqi903@...il.com>
Cc: Mark Fasheh <mark@...heh.com>
Cc: Joel Becker <jlbec@...lplan.org>
Cc: <stable@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/ocfs2/aops.c            |   12 ++++++++++--
 fs/ocfs2/cluster/masklog.h |    9 +++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2412,8 +2412,16 @@ static int ocfs2_dio_end_io(struct kiocb
 	/* 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);
 
--- 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 &&			\