From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Date: Thu, 15 Jul 2010 02:39:10 +0000 (+0900)
Subject: nilfs2: fix buffer head leak in nilfs_btnode_submit_block
X-Git-Tag: v2.6.36-rc1~500^2~10
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f8e6cc013b896d75d6ce4ec9e168014af1257fd8;p=platform%2Fkernel%2Flinux-stable.git

nilfs2: fix buffer head leak in nilfs_btnode_submit_block

nilfs_btnode_submit_block() refers to buffer head just before
returning from the function, but it releases the buffer head earlier
than that if nilfs_dat_translate() gets an error.

This has potential for oops in the erroneous case.  This fixes the
issue.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
---

diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
index 447ce47..0a6834b 100644
--- a/fs/nilfs2/btnode.c
+++ b/fs/nilfs2/btnode.c
@@ -100,6 +100,7 @@ int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
 {
 	struct buffer_head *bh;
 	struct inode *inode = NILFS_BTNC_I(btnc);
+	struct page *page;
 	int err;
 
 	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
@@ -107,6 +108,7 @@ int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
 		return -ENOMEM;
 
 	err = -EEXIST; /* internal code */
+	page = bh->b_page;
 
 	if (buffer_uptodate(bh) || buffer_dirty(bh))
 		goto found;
@@ -143,8 +145,8 @@ found:
 	*pbh = bh;
 
 out_locked:
-	unlock_page(bh->b_page);
-	page_cache_release(bh->b_page);
+	unlock_page(page);
+	page_cache_release(page);
 	return err;
 }