Re: [PATCH] btrfs: abort unlink trans in missed error case

[Eric Sandeen <sandeen@redhat.com>]

On 4/2/13 4:02 PM, Zach Brown wrote:
> __btrfs_unlink_inode() aborts its transaction when it sees errors after
> it removes the directory item.  But it missed the case where
> btrfs_del_dir_entries_in_log() returns an error.  If this happens then
> the unlink appears to fail but the items have been removed without
> updating the directory size.  The directory then has leaked bytes in
> i_size and can never be removed.
> 
> Adding the missing transaction abort at least makes this failure
> consistent with the other failure cases.
> 
> I noticed this while reading the code after someone on irc reported
> having a directory with i_size but no entries.  I tested it by forcing
> btrfs_del_dir_entries_in_log() to return -ENOMEM.

I was wondering if the transaction support should just be in the
err: goto case, and went looking.

I'm not familiar enough with this stuff yet, but what if i.e.
btrfs_delete_one_dir_name fails, should that also abort the transaction?

> Signed-off-by: Zach Brown <zab@redhat.com>
> ---
>  fs/btrfs/inode.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index d96ee30..80676ee 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -3619,6 +3619,8 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
>  					   dir, index);
>  	if (ret == -ENOENT)
>  		ret = 0;
> +	else if (ret)
> +		btrfs_abort_transaction(trans, root, ret);
>  err:
>  	btrfs_free_path(path);
>  	if (ret)
>