From: Namhyung Kim <namhyung@gmail.com>
Date: Thu, 28 Oct 2010 01:30:11 +0000 (-0400)
Subject: ext4: Check return value of sb_getblk() and friends
X-Git-Tag: v2.6.37-rc1~76^2^2~18
X-Git-Url: https://bbs.cooldavid.org/git/?p=net-next-2.6.git;a=commitdiff_plain;h=877836905da55e8f2426234f42a89287184949e9

ext4: Check return value of sb_getblk() and friends

Fail block allocation if sb_getblk() returns NULL. In that case,
sb_find_get_block() also likely to fail so that it should skip
calling ext4_forget().

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 58604fe11f4..077c3c9c432 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -761,6 +761,11 @@ static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
 		 * parent to disk.
 		 */
 		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
+		if (unlikely(!bh)) {
+			err = -EIO;
+			goto failed;
+		}
+
 		branch[n].bh = bh;
 		lock_buffer(bh);
 		BUFFER_TRACE(bh, "call get_create_access");
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index d732ef5a835..611c866ef3f 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4537,6 +4537,8 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 			if (!bh)
 				tbh = sb_find_get_block(inode->i_sb,
 							block + i);
+			if (unlikely(!tbh))
+				continue;
 			ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
 				    inode, tbh, block + i);
 		}