Re: [PATCH 2/2] src/attr_replace_test: dynamically adjust the max xattr size

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Jun 07, 2022 at 04:15:13PM +0100, Luís Henriques wrote:
> CephFS doesn't had a maximum xattr size.  Instead, it imposes a maximum
> size for the full set of an inode's xattrs names+values, which by default
> is 64K but it can be changed by a cluster admin.
> 
> Test generic/486 started to fail after fixing a ceph bug where this limit
> wasn't being imposed.  Adjust dynamically the size of the xattr being set
> if the error returned is -ENOSPC.
> 
> Signed-off-by: Luís Henriques <lhenriques@suse.de>
> ---
>  src/attr_replace_test.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/src/attr_replace_test.c b/src/attr_replace_test.c
> index cca8dcf8ff60..de18e643f469 100644
> --- a/src/attr_replace_test.c
> +++ b/src/attr_replace_test.c
> @@ -62,7 +62,10 @@ int main(int argc, char *argv[])
>  
>  	/* Then, replace it with bigger one, forcing short form to leaf conversion. */
>  	memset(value, '1', size);
> -	ret = fsetxattr(fd, name, value, size, XATTR_REPLACE);
> +	do {
> +		ret = fsetxattr(fd, name, value, size, XATTR_REPLACE);
> +		size -= 256;
> +	} while ((ret < 0) && (errno == ENOSPC) && (size > 0));

Isn't @size a size_t?  Which means that it can't be less than zero?  I
wouldn't count on st_blksize (or XATTR_SIZE_MAX) always being a multiple
of 256.

--D

>  	if (ret < 0) die();
>  	close(fd);
>