Re: [PATCH] btrfs: send: propagate errors from is_inode_existent()

[Qu Wenruo]

在 2026/8/10 19:17, Avi Weiss 写道:
> The direct-return refactor in commit b3047a42f55d ("btrfs: send:
> directly return from will_overwrite_ref() and simplify it") changed
> will_overwrite_ref() to return directly instead of going through the
> common out label.
>
> That resulted in a negative return value from is_inode_existent()
> to start being converted to 0, making lookup errors unable to be
> distinguished from the inode not existing.
>
> process_recorded_refs() expects negative errors from
> will_overwrite_ref() and aborts processing when it receives one.
>
> Return the value from is_inode_existent() to restore the previous error
> propagation behavior as it was before the refactor.
>
> Fixes: b3047a42f55d ("btrfs: send: directly return from will_overwrite_ref() and simplify it")
> Signed-off-by: Avi Weiss <thnkslprpt@xxxxxxxxx>
> ---
>   fs/btrfs/send.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index 3ae480c7474b..a888202397ed 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -2066,7 +2066,7 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
>   
>   	ret = is_inode_existent(sctx, dir, dir_gen, NULL, &parent_root_dir_gen);
>   	if (ret <= 0)
> -		return 0;
> +		return ret;

This behavior seems consistent with the later lookup_dir_item_inode(), 
where if we got ENOENT we just return 0.

Are you sure if we want to return -ENOENT in this case?
>   
>   	/*
>   	 * If we have a parent root we need to verify that the parent dir was
>
> base-commit: af5534fe2fbc006e83d75d6283dfc5ec75d5d780