Re: [PATCH v4 6/6] ext4: prevent getting empty inode buffer
From: "Theodore Ts'o" <tytso@mit.edu>
Date: 2021-08-31 03:02:48
On Thu, Aug 26, 2021 at 09:04:12PM +0800, Zhang Yi wrote:
quoted hunk ↗ jump to hunk
So this patch initialize the inode buffer by filling the in-mem inode contents if we skip read I/O, ensure that the buffer is really uptodate. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> --- fs/ext4/inode.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-)diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 3c36e701e30e..8b37f55b04ad 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c@@ -4446,8 +4446,8 @@ static int ext4_fill_raw_inode(struct inode *inode, struct ext4_inode *raw_inode * inode. */ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino, - struct ext4_iloc *iloc, int in_mem, - ext4_fsblk_t *ret_block) + struct inode *inode, struct ext4_iloc *iloc, + int in_mem, ext4_fsblk_t *ret_block)
In this patch you've added a new argument 'inode'. However, if in_mem
is true, and inode is NULL, the kernel will crash with a null pointer
dereference. Furthermore, whenever in_mem is false, the callers pass
in NULL for inode.
Given that, perhaps we should just drop the in_mem argument, and then
instead of
if (in_mem) {
we do:
if (inode && !ext4_test_inode_state(inode, EXT4_STATE_XATTR) {
with the comments adjusted accordingly?
I think it will make the code a bit simpler and readable.
What do you think?
- Ted