2010-10-19 08:22:14

by Namhyung Kim

Subject: [PATCH] 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 <[email protected]>
---
fs/ext4/inode.c | 5 +++++
fs/ext4/mballoc.c | 2 ++
2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4b8debe..12c0310 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -755,6 +755,11 @@ 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 4b4ad4b..48f5d10 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4531,6 +4531,8 @@ 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);
}
--
1.7.0.4

2010-10-25 14:51:06

by Theodore Ts'o

Subject: Re: [PATCH] ext4: Check return value of sb_getblk() and friends

On Tue, Oct 19, 2010 at 05:22:09PM +0900, Namhyung Kim wrote:
> 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 <[email protected]>

Thanks, I've added this patch to the ext4 patch queue.

- Ted