Re: [PATCH] btrfs: inode: Check if we get a valid inode before checking its mode.

[Nikolay Borisov <nborisov@suse.com>]

On 29.03.19 г. 9:12 ч., Qu Wenruo wrote:
> We should check the inode validation before checking the imode.
> 
> As btrfs_iget() could return ERR_PTR(), unlike previous path, we need to
> verify the inode before checking the imode.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
> To David:
> 
> Please fold this into 9944a5b5d26e ("btrfs: inode: Verify inode mode to avoid NULL pointer dereference") 
> of misc-next branch.
> ---
>  fs/btrfs/inode.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 3ee835cbb490..97f47dd295e8 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -5776,6 +5776,8 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
>  
>  	if (location.type == BTRFS_INODE_ITEM_KEY) {
>  		inode = btrfs_iget(dir->i_sb, &location, root, NULL);
> +		if (IS_ERR(inode))
> +			return inode;
>  
>  		/* Do extra check against inode mode with di_type */
>  		if (btrfs_inode_type(inode) != di_type) {
>