From: Eric Sandeen <sandeen@redhat.com>
Subject: [RHEL5.2 PATCH] - jbd: wait for already submitted t_sync_datalist 	buffer to complete
Date: Mon, 27 Aug 2007 11:42:34 -0500
Bugzilla: 250537
Message-Id: <46D2FEFA.20102@redhat.com>
Changelog: [fs] jbd: wait for t_sync_datalist buffer to complete


This is for bug 
Bug 250537: [PATCH] jbd: wait for already submitted t_sync_datalist buffer to complete

This change catches buffers which are locked but not dirty, i.e.
just submitted for IO, in the journal_submit_data_buffers() path
so that they are waited on just like buffers which were actually
submitted from that function.

The change has been upstream since late last year.

Thanks,

-Eric

==================================

X-Git-Tag: v2.6.20-rc2~15
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=6f5a9da1af5a8c286575c30c2706dc1fbef9164b

[PATCH] jbd: wait for already submitted t_sync_datalist buffer to complete

In the current jbd code, if a buffer on BJ_SyncData list is dirty and not
locked, the buffer is refiled to BJ_Locked list, submitted to the IO and
waited for IO completion.

But the fsstress test showed the case that when a buffer was already
submitted to the IO just before the buffer_dirty(bh) check, the buffer was
not waited for IO completion.

Following patch solves this problem.  If it is assumed that a buffer is
submitted to the IO before the buffer_dirty(bh) check and still being
written to disk, this buffer is refiled to BJ_Locked list.

Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Cc: Jan Kara <jack@ucw.cz>
Cc: "Stephen C. Tweedie" <sct@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

---

Index: linux-2.6.18-24.el5/fs/jbd/commit.c
===================================================================
--- linux-2.6.18-24.el5.orig/fs/jbd/commit.c
+++ linux-2.6.18-24.el5/fs/jbd/commit.c
@@ -248,8 +248,12 @@ write_out_data:
 				bufs = 0;
 				goto write_out_data;
 			}
-		}
-		else {
+		} else if (!locked && buffer_locked(bh)) {
+			__journal_file_buffer(jh, commit_transaction,
+						BJ_Locked);
+			jbd_unlock_bh_state(bh);
+			put_bh(bh);
+		} else {
 			BUFFER_TRACE(bh, "writeout complete: unfile");
 			__journal_unfile_buffer(jh);
 			jbd_unlock_bh_state(bh);