Re: [PATCH v7 5/7] fuse: Simplfiy the posix acl handling logic.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Miklos Szeredi <mszeredi@xxxxxxxxxx> writes:

> On Tue, Feb 27, 2018 at 12:53 AM, Eric W. Biederman
> <ebiederm@xxxxxxxxxxxx> wrote:
>> Rename the fuse connection flag posix_acl to cached_posix_acl as that
>> is what it actually means.  That fuse will cache and operate on the
>> cached value of the posix acl.
>>
>> When fc->cached_posix_acl is not set, set ACL_DONT_CACHE on the inode
>> so that get_acl and friends won't cache the acl values even if they
>> are called.
>>
>> Replace forget_all_cached_acls with fuse_forget_cached_acls.  This
>> wrapper only takes effect when cached_posix_acl is true to prevent
>> losing the nocache or noxattr status in when posix acls are not
>> cached.
>
> Shouldn't forget_cached_acl() be taught about ACL_DONT_CACHE?  I think
> it makes sense to generally not clear ACL_DONT_CACHE, since it's not
> an actual acl value that needs forgetting.

After stopping to make certain I understand the issues, I don't think
it makes sense to teach forget_cached_acl about ACL_DONT_CACHE.

If you are fogetting a cached attribute ACL_DONT_CACHE simply doesn't
make sense.

Further it makes sense to cache a negative result for fuse when
!fc->no_getxattr.  Even if you would ordinarily not cache posix acls.

So I think the better plan is to teach the posix acl code how to not
cache results on a case by case basis.  As I did in my rfc patch I
posted a little earlier today.  That works with forget_cached_acl and it
supports local reasoning.  Further while the performance might not be as
good as ACL_DONT_CACHE I don't think that matters as always going to the
fuse server to get acls is almost certainly going to dominate the acl
costs.

Eric
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/containers



[Index of Archives]     [Cgroups]     [Netdev]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux