Re: [PATCH 1/2] quota: Change quotactl_path() systcall to an fd-based one

On Thu 03-06-21 11:41:02, Sascha Hauer wrote:

Hello Honza,

On Wed, Jun 02, 2021 at 05:15:52PM +0200, Jan Kara wrote:

quoted

Some users have pointed out that path-based syscalls are problematic in
some environments and at least directory fd argument and possibly also
resolve flags are desirable for such syscalls. Rather than
reimplementing all details of pathname lookup and following where it may
eventually evolve, let's go for full file descriptor based syscall
similar to how ioctl(2) works since the beginning. Managing of quotas
isn't performance sensitive so the extra overhead of open does not
matter and we are able to consume O_PATH descriptors as well which makes
open cheap anyway. Also for frequent operations (such as retrieving
usage information for all users) we can reuse single fd and in fact get
even better performance as well as avoiding races with possible remounts
etc.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/quota/quota.c                  | 27 ++++++++++++---------------
 include/linux/syscalls.h          |  4 ++--
 include/uapi/asm-generic/unistd.h |  4 ++--
 kernel/sys_ni.c                   |  2 +-
 4 files changed, 17 insertions(+), 20 deletions(-)

Thanks for taking care of this.

I also gave this some testing and it's working ok for me, so at least I
can give you my:

Tested-by: Sascha Hauer <s.hauer@pengutronix.de>

Thanks!

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR