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List:       linux-stable-commits
Subject:    patch nilfs2-fix-missing-zero-fill-initialization-of-btree-node-cache.patch added to 2.6.30-stable t
From:       <gregkh () suse ! de>
Date:       2009-09-30 22:50:41
Message-ID: 20090930225105.513504879C () coco ! kroah ! org
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This is a note to let you know that we have just queued up the patch titled

    Subject: nilfs2: fix missing zero-fill initialization of btree node cache

to the 2.6.30-stable tree.  Its filename is

    nilfs2-fix-missing-zero-fill-initialization-of-btree-node-cache.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


From 1f28fcd925b2b3157411bbd08f0024b55b70d8dd Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Date: Mon, 28 Sep 2009 01:46:11 +0900
Subject: nilfs2: fix missing zero-fill initialization of btree node cache

From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

commit 1f28fcd925b2b3157411bbd08f0024b55b70d8dd upstream.

This will fix file system corruption which infrequently happens after
mount.  The problem was reported from users with the title "[NILFS
users] Fail to mount NILFS." (Message-ID:
<200908211918.34720.yuri@itinteg.net>), and so forth.  I've also
experienced the corruption multiple times on kernel 2.6.30 and 2.6.31.

The problem turned out to be caused due to discordance between
mapping->nrpages of a btree node cache and the actual number of pages
hung on the cache; if the mapping->nrpages becomes zero even as it has
pages, truncate_inode_pages() returns without doing anything.  Usually
this is harmless except it may cause page leak, but garbage collection
fairly infrequently sees a stale page remained in the btree node cache
of DAT (i.e. disk address translation file of nilfs), and induces the
corruption.

I identified a missing initialization in btree node caches was the
root cause.  This corrects the bug.

I've tested this for kernel 2.6.30 and 2.6.31.

Reported-by: Yuri Chislov <yuri@itinteg.net>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/nilfs2/btnode.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/nilfs2/btnode.c
+++ b/fs/nilfs2/btnode.c
@@ -36,6 +36,7 @@
 
 void nilfs_btnode_cache_init_once(struct address_space *btnc)
 {
+	memset(btnc, 0, sizeof(*btnc));
 	INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC);
 	spin_lock_init(&btnc->tree_lock);
 	INIT_LIST_HEAD(&btnc->private_list);


Patches currently in stable-queue which might be from konishi.ryusuke@lab.ntt.co.jp are

queue-2.6.30/nilfs2-fix-missing-zero-fill-initialization-of-btree-node-cache.patch
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