On Mon, Mar 26, 2018 at 12:22:59PM -0700, Darrick J. Wong wrote:
> On Sun, Mar 25, 2018 at 01:16:36PM +0800, Chengguang Xu wrote:
> > In current implementation, we size the fs(sub-fs via project quota) at
> > the soft limit and simply call it 100% used if the limit is exceeded.
> > It is reasonable when only a soft limit is set, but we should use the
> > hard limit if both hard/soft limits are set, so that quota-df reflects
> > the usage information more accurately.
>
> This is the followup patch to "xfs: adjust size/used/avail information
> for quota-df", correct?
>
> I also wonder, statvfs is a weird interface since there's no way to send
> back usage information, just blocks/free/avail. Isn't it more
> appropriate to use xfs_quota to find out the usage, hard limit, and soft
> limit of a directory?
>
> > Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
> > ---
> > fs/xfs/xfs_qm_bhv.c | 12 ++++++------
> > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_qm_bhv.c b/fs/xfs/xfs_qm_bhv.c
> > index 2be6d27..43b0fe8 100644
> > --- a/fs/xfs/xfs_qm_bhv.c
> > +++ b/fs/xfs/xfs_qm_bhv.c
> > @@ -35,9 +35,9 @@
> > {
> > uint64_t limit;
> >
> > - limit = dqp->q_core.d_blk_softlimit ?
> > - be64_to_cpu(dqp->q_core.d_blk_softlimit) :
> > - be64_to_cpu(dqp->q_core.d_blk_hardlimit);
> > + limit = dqp->q_core.d_blk_hardlimit ?
> > + be64_to_cpu(dqp->q_core.d_blk_hardlimit) :
> > + be64_to_cpu(dqp->q_core.d_blk_softlimit);
>
> Ok, so now we report hard limit for f_blocks over the soft limit. So if
> this is the state of the filesystem:
>
> # xfs_quota -xc 'report -ahp'
> Project quota on /opt (/dev/sdf)
> Blocks
> Project ID Used Soft Hard Warn/Grace
> ---------- ---------------------------------
> #0 0 0 0 00 [------]
> vms 3M 2M 3M 00 [7 days]
>
> Then the df output goes from:
>
> # df /opt/b
> Filesystem Size Used Avail Use% Mounted on
> /dev/sdf 2.0M 2.0M 0 100% /opt
>
> to this:
>
> # df /opt/b
> Filesystem Size Used Avail Use% Mounted on
> /dev/sdf 3.0M 3.0M 0 100% /opt
>
> That makes to me, but as it /does/ change the behavior of an existing
> user-visible interface, I would like to know more about the current
> behavior. Dave/Christoph, do you recall why df reports the project
> quota soft limit?
>
> ----
>
> Just for fun let's try the same on ext4...
>
> $ dd if=/dev/zero >> /opt/b/a
> ^C4129977+0 records in
> 4129977+0 records out
> 2114548224 bytes (2.1 GB, 2.0 GiB) copied, 23.9179 s, 88.4 MB/s
>
> $ sudo xfs_quota -fxc 'report -ahp' /opt
> Project quota on /opt (/dev/sdf)
> Blocks
> Project ID Used Soft Hard Warn/Grace
> ---------- ---------------------------------
> #0 20K 0 0 00 [------]
> vms 2.0G 2M 3M 00 [-none-]
>
> <facepalm>
>
> Only 1000x over soft quota...
Heh. One has to format with project quotas /and/ mount with prjquota.
> $ df /opt/b
> Filesystem Size Used Avail Use% Mounted on
> /dev/sdf 13G 2.8G 8.9G 24% /opt
>
> I guess we're going to need a couple more tests, then? One to check
> that we enforce project quotas, and another to check what we're
> reporting via df?
I think generic/386 tests the df results with project quota...?
> --D
>
> > if (limit && statp->f_blocks > limit) {
> > statp->f_blocks = limit;
> > statp->f_bfree = statp->f_bavail =
> > @@ -45,9 +45,9 @@
> > (statp->f_blocks - dqp->q_res_bcount) : 0;
> > }
> >
> > - limit = dqp->q_core.d_ino_softlimit ?
> > - be64_to_cpu(dqp->q_core.d_ino_softlimit) :
> > - be64_to_cpu(dqp->q_core.d_ino_hardlimit);
> > + limit = dqp->q_core.d_ino_hardlimit ?
> > + be64_to_cpu(dqp->q_core.d_ino_hardlimit) :
> > + be64_to_cpu(dqp->q_core.d_ino_softlimit);
> > if (limit && statp->f_files > limit) {
> > statp->f_files = limit;
> > statp->f_ffree =
> > --
> > 1.8.3.1
> >
> > --
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