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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-05-15 15:51:54 +0400
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-05-16 11:31:41 +0400
commitcb14a18465686ea6add51b1008865b8174c28bd7 (patch)
tree9e1b7aa466e83c77628fa74af00049893db84c40 /fs/ubifs/journal.c
parentc49139d8096dc1c392455dbc3f158b46038fc9d4 (diff)
downloadlinux-cb14a18465686ea6add51b1008865b8174c28bd7.tar.xz
UBIFS: synchronize write-buffer before switching to the next bud
Currently when UBIFS fills up the current bud (which is the last in the journal head) and switches to the next bud, it first writes the log reference node for the next bud and only after this synchronizes the write-buffer of the previous bud. This is not a big deal, but an unclean power cut may lead to a situation when we have corruption in a next-to-last bud, although it is much more logical that we have to have corruption only in the last bud. This patch also removes write-buffer synchronization from 'ubifs_wbuf_seek_nolock()' because this is not needed anymore (we synchronize the write-buffer explicitly everywhere now) and also because this is just prone to various errors. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'fs/ubifs/journal.c')
-rw-r--r--fs/ubifs/journal.c25
1 files changed, 15 insertions, 10 deletions
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index ce55a4807cdc..34b1679e6e3a 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -141,14 +141,8 @@ again:
* LEB with some empty space.
*/
lnum = ubifs_find_free_space(c, len, &offs, squeeze);
- if (lnum >= 0) {
- /* Found an LEB, add it to the journal head */
- err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
- if (err)
- goto out_return;
- /* A new bud was successfully allocated and added to the log */
+ if (lnum >= 0)
goto out;
- }
err = lnum;
if (err != -ENOSPC)
@@ -203,12 +197,23 @@ again:
return 0;
}
- err = ubifs_add_bud_to_log(c, jhead, lnum, 0);
- if (err)
- goto out_return;
offs = 0;
out:
+ /*
+ * Make sure we synchronize the write-buffer before we add the new bud
+ * to the log. Otherwise we may have a power cut after the log
+ * reference node for the last bud (@lnum) is written but before the
+ * write-buffer data are written to the next-to-last bud
+ * (@wbuf->lnum). And the effect would be that the recovery would see
+ * that there is corruption in the next-to-last bud.
+ */
+ err = ubifs_wbuf_sync_nolock(wbuf);
+ if (err)
+ goto out_return;
+ err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
+ if (err)
+ goto out_return;
err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs, wbuf->dtype);
if (err)
goto out_unlock;