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From: npiggin@suse.de
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org,
	Mark Fasheh <mark.fasheh@oracle.com>,
	Linux Memory Management <linux-mm@kvack.org>
Subject: [patch 11/41] fs: fix data-loss on error
Date: Fri, 25 May 2007 22:21:55 +1000	[thread overview]
Message-ID: <20070524053154.910657000@linux.local0.net> (raw)
In-Reply-To: <20070524052844.860329000@suse.de>

[-- Attachment #1: fs-dataloss-stop.patch --]
[-- Type: text/plain, Size: 1340 bytes --]

New buffers against uptodate pages are simply be marked uptodate, while the
buffer_new bit remains set. This causes error-case code to zero out parts
of those buffers because it thinks they contain stale data: wrong, they
are actually uptodate so this is a data loss situation.

Fix this by actually clearning buffer_new and marking the buffer dirty. It
makes sense to always clear buffer_new before setting a buffer uptodate.

Cc: Linux Memory Management <linux-mm@kvack.org>
Cc: Linux Filesystems <linux-fsdevel@vger.kernel.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>

 fs/buffer.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -1816,7 +1816,9 @@ static int __block_prepare_write(struct 
 				unmap_underlying_metadata(bh->b_bdev,
 							bh->b_blocknr);
 				if (PageUptodate(page)) {
+					clear_buffer_new(bh);
 					set_buffer_uptodate(bh);
+					mark_buffer_dirty(bh);
 					continue;
 				}
 				if (block_end > to || block_start < from) {

-- 

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  parent reply	other threads:[~2007-05-25 12:21 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20070524052844.860329000@suse.de>
2007-05-25 12:21 ` [patch 01/41] mm: revert KERNEL_DS buffered write optimisation npiggin
2007-05-25 12:21 ` [patch 02/41] Revert 81b0c8713385ce1b1b9058e916edcf9561ad76d6 npiggin, Andrew Morton
2007-05-25 12:21 ` [patch 03/41] Revert 6527c2bdf1f833cc18e8f42bd97973d583e4aa83 npiggin, Andrew Morton
2007-05-25 12:21 ` [patch 04/41] mm: clean up buffered write code npiggin, Andrew Morton
2007-05-25 12:21 ` [patch 05/41] mm: debug write deadlocks npiggin
2007-05-25 12:21 ` [patch 06/41] mm: trim more holes npiggin
2007-05-25 12:21 ` [patch 07/41] mm: buffered write cleanup npiggin
2007-05-25 12:21 ` [patch 08/41] mm: write iovec cleanup npiggin
2007-05-25 12:21 ` [patch 09/41] mm: fix pagecache write deadlocks npiggin
2007-05-25 12:21 ` [patch 10/41] mm: buffered write iterator npiggin
2007-05-25 12:21 ` npiggin [this message]
2007-05-25 12:21 ` [patch 12/41] fs: introduce write_begin, write_end, and perform_write aops npiggin
2007-05-31  4:30   ` Andrew Morton
2007-05-31  4:43     ` Nick Piggin
2007-05-31  4:52       ` Andrew Morton
2007-05-31  4:57         ` Nick Piggin
2007-05-31  5:11           ` Andrew Morton
2007-05-31  5:15             ` Nick Piggin
2007-05-31  7:05               ` Andrew Morton
2007-06-01  1:18                 ` Nick Piggin
2007-05-25 12:21 ` [patch 13/41] mm: restore KERNEL_DS optimisations npiggin
     [not found] <20070514060619.689648000@wotan.suse.de>
2007-05-14  6:06 ` [patch 11/41] fs: fix data-loss on error npiggin

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