Re: [PATCH resend v5 02/11] ceph: add caps perf metric for each session

[Xiubo Li <xiubli@xxxxxxxxxx>]

On 2020/1/31 9:34, Xiubo Li wrote:
> On 2020/1/31 3:00, Jeffrey Layton wrote:
> > On Thu, 2020-01-30 at 10:22 +0800, Xiubo Li wrote:
> > > On 2020/1/29 22:21, Jeff Layton wrote:
> > > > On Wed, 2020-01-29 at 03:27 -0500, xiubli@xxxxxxxxxx wrote:
> > > > > From: Xiubo Li <xiubli@xxxxxxxxxx>
> > > > >
> > > > > This will fulfill the caps hit/miss metric for each session. When
> > > > > checking the "need" mask and if one cap has the subset of the
> > > > > "need"
> > > > > mask it means hit, or missed.
> > > > >
> > > > > item          total           miss            hit
> > > > > -------------------------------------------------
> > > > > d_lease       295             0               993
> > > > >
> > > > > session       caps            miss            hit
> > > > > -------------------------------------------------
> > > > > 0             295             107             4119
> > > > > 1             1               107             9
> > > > >
> > > > > URL: https://tracker.ceph.com/issues/43215
> > > > > Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> > > > > ---
> > > > >    fs/ceph/acl.c        |  2 ++
> > > > >    fs/ceph/addr.c       |  2 ++
> > > > >    fs/ceph/caps.c       | 74
> > > > > ++++++++++++++++++++++++++++++++++++++++++++
> > > > >    fs/ceph/debugfs.c    | 20 ++++++++++++
> > > > >    fs/ceph/dir.c        |  9 ++++--
> > > > >    fs/ceph/file.c       |  3 ++
> > > > >    fs/ceph/mds_client.c | 16 +++++++++-
> > > > >    fs/ceph/mds_client.h |  3 ++
> > > > >    fs/ceph/quota.c      |  9 ++++--
> > > > >    fs/ceph/super.h      | 11 +++++++
> > > > >    fs/ceph/xattr.c      | 17 ++++++++--
> > > > >    11 files changed, 158 insertions(+), 8 deletions(-)
> > > > >
> > > > > diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
> > > > > index 26be6520d3fb..58e119e3519f 100644
> > > > > --- a/fs/ceph/acl.c
> > > > > +++ b/fs/ceph/acl.c
> > > > > @@ -22,6 +22,8 @@ static inline void ceph_set_cached_acl(struct
> > > > > inode *inode,
> > > > >        struct ceph_inode_info *ci = ceph_inode(inode);
> > > > >           spin_lock(&ci->i_ceph_lock);
> > > > > +    __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > > +
> > > > >        if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED,
> > > > > 0))
> > > > >            set_cached_acl(inode, type, acl);
> > > > >        else
> > > > > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> > > > > index 7ab616601141..29d4513eff8c 100644
> > > > > --- a/fs/ceph/addr.c
> > > > > +++ b/fs/ceph/addr.c
> > > > > @@ -1706,6 +1706,8 @@ int ceph_uninline_data(struct file *filp,
> > > > > struct page *locked_page)
> > > > >                err = -ENOMEM;
> > > > >                goto out;
> > > > >            }
> > > > > +
> > > > > +        ceph_caps_metric(ci, CEPH_STAT_CAP_INLINE_DATA);
> > > > Should a check for inline data really count here?
> > > Currently all the INLINE_DATA is in 'force' mode, so we can ignore
> > > it.
> > > > >            err = __ceph_do_getattr(inode, page,
> > > > >                        CEPH_STAT_CAP_INLINE_DA
> > > > > TA, true);
> > > > >            if (err < 0) {
> > > > > diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> > > > > index 7fc87b693ba4..af2e9e826f8c 100644
> > > > > --- a/fs/ceph/caps.c
> > > > > +++ b/fs/ceph/caps.c
> > > > > @@ -783,6 +783,75 @@ static int __cap_is_valid(struct ceph_cap
> > > > > *cap)
> > > > >        return 1;
> > > > >    }
> > > > >    +/*
> > > > > + * Counts the cap metric.
> > > > > + */
> > > > This needs some comments. Specifically, what should this be
> > > > counting and
> > > > how?
> > > Will add it.
> > >
> > > The __ceph_caps_metric() will traverse the inode's i_caps try to get
> > > the
> > > 'issued' excepting the 'invoking' caps until it get enough caps in
> > > 'mask'. The i_caps traverse logic is following
> > > __ceph_caps_issued_mask().
> > >
> > >
> > > > > +void __ceph_caps_metric(struct ceph_inode_info *ci, int mask)
> > > > > +{
> > > > > +    int have = ci->i_snap_caps;
> > > > > +    struct ceph_mds_session *s;
> > > > > +    struct ceph_cap *cap;
> > > > > +    struct rb_node *p;
> > > > > +    bool skip_auth = false;
> > > > > +
> > > > > +    lockdep_assert_held(&ci->i_ceph_lock);
> > > > > +
> > > > > +    if (mask <= 0)
> > > > > +        return;
> > > > > +
> > > > > +    /* Counts the snap caps metric in the auth cap */
> > > > > +    if (ci->i_auth_cap) {
> > > > > +        cap = ci->i_auth_cap;
> > > > > +        if (have) {
> > > > > +            have |= cap->issued;
> > > > > +
> > > > > +            dout("%s %p cap %p issued %s, mask %s\n",
> > > > > __func__,
> > > > > +                 &ci->vfs_inode, cap, ceph_cap_string(cap-
> > > > > > issued),
> > > > > +                 ceph_cap_string(mask));
> > > > > +
> > > > > +            s = ceph_get_mds_session(cap->session);
> > > > > +            if (s) {
> > > > > +                if (mask & have)
> > > > > +                    percpu_counter_inc(&s-
> > > > > > i_caps_hit);
> > > > > +                else
> > > > > +                    percpu_counter_inc(&s-
> > > > > > i_caps_mis);
> > > > > +                ceph_put_mds_session(s);
> > > > > +            }
> > > > > +            skip_auth = true;
> > > > > +        }
> > > > > +    }
> > > > > +
> > > > > +    if ((mask & have) == mask)
> > > > > +        return;
> > > > > +
> > > > > +    /* Checks others */
> > > > > +    for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
> > > > > +        cap = rb_entry(p, struct ceph_cap, ci_node);
> > > > > +        if (!__cap_is_valid(cap))
> > > > > +            continue;
> > > > > +
> > > > > +        if (skip_auth && cap == ci->i_auth_cap)
> > > > > +            continue;
> > > > > +
> > > > > +        dout("%s %p cap %p issued %s, mask %s\n", __func__,
> > > > > +             &ci->vfs_inode, cap, ceph_cap_string(cap->issued),
> > > > > +             ceph_cap_string(mask));
> > > > > +
> > > > > +        s = ceph_get_mds_session(cap->session);
> > > > > +        if (s) {
> > > > > +            if (mask & cap->issued)
> > > > > + percpu_counter_inc(&s->i_caps_hit);
> > > > > +            else
> > > > > + percpu_counter_inc(&s->i_caps_mis);
> > > > > +            ceph_put_mds_session(s);
> > > > > +        }
> > > > > +
> > > > > +        have |= cap->issued;
> > > > > +        if ((mask & have) == mask)
> > > > > +            return;
> > > > > +    }
> > > > > +}
> > > > > +
> > > > I'm trying to understand what happens with the above when more than
> > > > one
> > > > ceph_cap has the same bit set in "issued". For instance:
> > > >
> > > > Suppose we're doing the check for a statx call, and we're trying to
> > > > get
> > > > caps for pAsFsLs. We have two MDS's and they've each granted us
> > > > caps for
> > > > the inode, say:
> > > >
> > > > MDS 0: pAs
> > > > MDS 1: pAsLsFs
> > > >
> > > > We check the cap0 first, and consider it a hit, and then we check
> > > > cap1
> > > > and consider it a hit as well. So that seems like it's being
> > > > double-
> > > > counted.
> > > Yeah, it will.
> > >
> > > In case2:
> > >
> > > MDS 0: pAsFs
> > >
> > > MDS 1: pAsLs
> > >
> > > For this case and yours both the i_cap0 and i_cap1 are 'hit'.
> > >
> > >
> > > In case3 :
> > >
> > > MDS0: pAsFsLs
> > >
> > > MDS1: pAs
> > >
> > > Only the i_cap0 is 'hit'.  i_cap1 will not be counted any 'hit' or
> > > 'mis'.
> > >
> > >
> > > In case4:
> > >
> > > MDS0: p
> > >
> > > MDS1: pAsLsFs
> > >
> > > i_cap0 will 'mis' and i_cap1 will 'hit'.
> > >
> > >
> > > All the logic are the same with __ceph_caps_issued_mask() does.
> > >
> > > The 'hit' means to get all the caps in 'mask we have checked the
> > > i_cap[0~N] and if they have a subset in 'mask', and the 'mis' means
> > > we
> > > have checked the i_cap[0~N] but they do not.
> > >
> > > For the i_cap[N+1 ~ M], if we won't touch them because we have
> > > already
> > > gotten enough caps needed in 'mask', they won't count any 'hit' or
> > > 'mis'
> > >
> > > All in all, the current logic is that the 'hit' means 'touched' and
> > > it
> > > have some of what we needed, and the 'mis' means 'touched' and
> > > missed
> > > any of what we needed.
> > That seems sort of arbitrary, given that you're going to get different
> > results depending on the index of the MDS with the caps. For instance:
> >
> >
> > MDS0: pAsLsFs
> > MDS1: pAs
> >
> > ...vs...
> >
> > MDS0: pAs
> > MDS1: pAsLsFs
> >
> > If we assume we're looking for pAsLsFs, then the first scenario will
> > just end up with 1 hit and the second will give you 2. AFAIU, the two
> > MDSs are peers, so it really seems like the index should not matter
> > here.
> >
> > I'm really struggling to understand how these numbers will be useful.
> > What, specifically, are we trying to count here and why?
>
> Maybe we need count the hit/mis only once, the fake code like:
>
> // Case1: check the auth caps first
>
> if (auth_cap & mask == mask) {
>
>     s->hit++;
>
>     return;
>
> }
>
> // Case2: check all the other one by one
>
> for (caps : i_caps) {
>
>     if (caps & mask == mask) {
>
>         s->hit++;
>
>         return;
>
>     }
>
>     c |= caps;
>
> }
>
> // Case3:
>
> if (c & mask == mask)
>
>     s->hit++;
>
> else
>
>     s->mis++;
>
> return;
>
> ....
>
> And for the session 's->' here, if one i_cap can hold all the 'mask' 
> requested, like the Case1 and Case2 it will be i_cap's corresponding 
> session. Or for Case3 we could choose any session.
>
> But the above is still not very graceful of counting the cap metrics too.
>
> IMO, for the cap hit/miss counter should be a global one just like the 
> dentry_lease does in [PATCH 01/11], will this make sense ?
Currently in fuse client, for each inode it is its auth_cap->session's 
responsibility to do all the cap hit/mis counting if it has a auth_cap, 
or choose any one exist.

Maybe this is one acceptable approach.

> Thanks,
>
>
> > > > ISTM, that what you really want to do here is logically or all of
> > > > the
> > > > cap->issued fields together, and then check that vs. the mask
> > > > value, and
> > > > count only one hit or miss per inode.
> > > >
> > > > That said, it's not 100% clear what you're counting as a hit or
> > > > miss
> > > > here, so please let me know if I have that wrong.
> > > > >    /*
> > > > >     * Return set of valid cap bits issued to us.  Note that caps
> > > > > time
> > > > >     * out, and may be invalidated in bulk if the client session
> > > > > times out
> > > > > @@ -2746,6 +2815,7 @@ static void check_max_size(struct inode
> > > > > *inode, loff_t endoff)
> > > > >    int ceph_try_get_caps(struct inode *inode, int need, int want,
> > > > >                  bool nonblock, int *got)
> > > > >    {
> > > > > +    struct ceph_inode_info *ci = ceph_inode(inode);
> > > > >        int ret;
> > > > >           BUG_ON(need & ~CEPH_CAP_FILE_RD);
> > > > > @@ -2758,6 +2828,7 @@ int ceph_try_get_caps(struct inode *inode,
> > > > > int need, int want,
> > > > >        BUG_ON(want & ~(CEPH_CAP_FILE_CACHE |
> > > > > CEPH_CAP_FILE_LAZYIO |
> > > > >                CEPH_CAP_FILE_SHARED |
> > > > > CEPH_CAP_FILE_EXCL |
> > > > >                CEPH_CAP_ANY_DIR_OPS));
> > > > > +    ceph_caps_metric(ci, need | want);
> > > > >        ret = try_get_cap_refs(inode, need, want, 0, nonblock,
> > > > > got);
> > > > >        return ret == -EAGAIN ? 0 : ret;
> > > > >    }
> > > > > @@ -2784,6 +2855,8 @@ int ceph_get_caps(struct file *filp, int
> > > > > need, int want,
> > > > >            fi->filp_gen != READ_ONCE(fsc->filp_gen))
> > > > >            return -EBADF;
> > > > >    +    ceph_caps_metric(ci, need | want);
> > > > > +
> > > > >        while (true) {
> > > > >            if (endoff > 0)
> > > > >                check_max_size(inode, endoff);
> > > > > @@ -2871,6 +2944,7 @@ int ceph_get_caps(struct file *filp, int
> > > > > need, int want,
> > > > >                 * getattr request will bring inline
> > > > > data into
> > > > >                 * page cache
> > > > >                 */
> > > > > +            ceph_caps_metric(ci,
> > > > > CEPH_STAT_CAP_INLINE_DATA);
> > > > >                ret = __ceph_do_getattr(inode, NULL,
> > > > >                            CEPH_STAT_CAP_I
> > > > > NLINE_DATA,
> > > > >                            true);
> > > > > diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> > > > > index 40a22da0214a..c132fdb40d53 100644
> > > > > --- a/fs/ceph/debugfs.c
> > > > > +++ b/fs/ceph/debugfs.c
> > > > > @@ -128,6 +128,7 @@ static int metric_show(struct seq_file *s,
> > > > > void *p)
> > > > >    {
> > > > >        struct ceph_fs_client *fsc = s->private;
> > > > >        struct ceph_mds_client *mdsc = fsc->mdsc;
> > > > > +    int i;
> > > > >           seq_printf(s,
> > > > > "item          total           miss            hit\n");
> > > > >        seq_printf(s, "--------------------------------------
> > > > > -----------\n");
> > > > > @@ -137,6 +138,25 @@ static int metric_show(struct seq_file *s,
> > > > > void *p)
> > > > >               percpu_counter_sum(&mdsc-
> > > > > > metric.d_lease_mis),
> > > > >               percpu_counter_sum(&mdsc-
> > > > > > metric.d_lease_hit));
> > > > >    +    seq_printf(s, "\n");
> > > > > +    seq_printf(s,
> > > > > "session       caps            miss            hit\n");
> > > > > +    seq_printf(s, "----------------------------------------------
> > > > > ---\n");
> > > > > +
> > > > > +    mutex_lock(&mdsc->mutex);
> > > > > +    for (i = 0; i < mdsc->max_sessions; i++) {
> > > > > +        struct ceph_mds_session *session;
> > > > > +
> > > > > +        session = __ceph_lookup_mds_session(mdsc, i);
> > > > > +        if (!session)
> > > > > +            continue;
> > > > > +        seq_printf(s, "%-14d%-16d%-16lld%lld\n", i,
> > > > > +               session->s_nr_caps,
> > > > > + percpu_counter_sum(&session->i_caps_mis),
> > > > > + percpu_counter_sum(&session->i_caps_hit));
> > > > > +        ceph_put_mds_session(session);
> > > > > +    }
> > > > > +    mutex_unlock(&mdsc->mutex);
> > > > > +
> > > > >        return 0;
> > > > >    }
> > > > >    diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> > > > > index 658c55b323cc..33eb239e09e2 100644
> > > > > --- a/fs/ceph/dir.c
> > > > > +++ b/fs/ceph/dir.c
> > > > > @@ -313,7 +313,7 @@ static int ceph_readdir(struct file *file,
> > > > > struct dir_context *ctx)
> > > > >        struct ceph_fs_client *fsc =
> > > > > ceph_inode_to_client(inode);
> > > > >        struct ceph_mds_client *mdsc = fsc->mdsc;
> > > > >        int i;
> > > > > -    int err;
> > > > > +    int err, ret = -1;
> > > > >        unsigned frag = -1;
> > > > >        struct ceph_mds_reply_info_parsed *rinfo;
> > > > >    @@ -346,13 +346,16 @@ static int ceph_readdir(struct file *file,
> > > > > struct dir_context *ctx)
> > > > >            !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
> > > > >            ceph_snap(inode) != CEPH_SNAPDIR &&
> > > > >            __ceph_dir_is_complete_ordered(ci) &&
> > > > > -        __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
> > > > > +        (ret = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED,
> > > > > 1))) {
> > > > >            int shared_gen = atomic_read(&ci-
> > > > > > i_shared_gen);
> > > > > +        __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > >            spin_unlock(&ci->i_ceph_lock);
> > > > >            err = __dcache_readdir(file, ctx, shared_gen);
> > > > >            if (err != -EAGAIN)
> > > > >                return err;
> > > > >        } else {
> > > > > +        if (ret != -1)
> > > > > +            __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > >            spin_unlock(&ci->i_ceph_lock);
> > > > >        }
> > > > >    @@ -757,6 +760,8 @@ static struct dentry *ceph_lookup(struct
> > > > > inode *dir, struct dentry *dentry,
> > > > >            struct ceph_dentry_info *di =
> > > > > ceph_dentry(dentry);
> > > > >               spin_lock(&ci->i_ceph_lock);
> > > > > +        __ceph_caps_metric(ci, CEPH_CAP_FILE_SHARED);
> > > > > +
> > > > >            dout(" dir %p flags are %d\n", dir, ci-
> > > > > > i_ceph_flags);
> > > > >            if (strncmp(dentry->d_name.name,
> > > > >                    fsc->mount_options->snapdir_name,
> > > > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > > > > index 1e6cdf2dfe90..c78dfbbb7b91 100644
> > > > > --- a/fs/ceph/file.c
> > > > > +++ b/fs/ceph/file.c
> > > > > @@ -384,6 +384,8 @@ int ceph_open(struct inode *inode, struct
> > > > > file *file)
> > > > >         * asynchronously.
> > > > >         */
> > > > >        spin_lock(&ci->i_ceph_lock);
> > > > > +    __ceph_caps_metric(ci, wanted);
> > > > > +
> > > > >        if (__ceph_is_any_real_caps(ci) &&
> > > > >            (((fmode & CEPH_FILE_MODE_WR) == 0) || ci-
> > > > > > i_auth_cap)) {
> > > > >            int mds_wanted = __ceph_caps_mds_wanted(ci,
> > > > > true);
> > > > > @@ -1340,6 +1342,7 @@ static ssize_t ceph_read_iter(struct kiocb
> > > > > *iocb, struct iov_iter *to)
> > > > >                    return -ENOMEM;
> > > > >            }
> > > > >    +        ceph_caps_metric(ci, CEPH_STAT_CAP_INLINE_DATA);
> > > > >            statret = __ceph_do_getattr(inode, page,
> > > > >                            CEPH_STAT_CAP_INLIN
> > > > > E_DATA, !!page);
> > > > >            if (statret < 0) {
> > > > > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > > > > index a24fd00676b8..141c1c03636c 100644
> > > > > --- a/fs/ceph/mds_client.c
> > > > > +++ b/fs/ceph/mds_client.c
> > > > > @@ -558,6 +558,8 @@ void ceph_put_mds_session(struct
> > > > > ceph_mds_session *s)
> > > > >        if (refcount_dec_and_test(&s->s_ref)) {
> > > > >            if (s->s_auth.authorizer)
> > > > >                ceph_auth_destroy_authorizer(s-
> > > > > > s_auth.authorizer);
> > > > > +        percpu_counter_destroy(&s->i_caps_hit);
> > > > > +        percpu_counter_destroy(&s->i_caps_mis);
> > > > >            kfree(s);
> > > > >        }
> > > > >    }
> > > > > @@ -598,6 +600,7 @@ static struct ceph_mds_session
> > > > > *register_session(struct ceph_mds_client *mdsc,
> > > > >                             int mds)
> > > > >    {
> > > > >        struct ceph_mds_session *s;
> > > > > +    int err;
> > > > >           if (mds >= mdsc->mdsmap->possible_max_rank)
> > > > >            return ERR_PTR(-EINVAL);
> > > > > @@ -612,8 +615,10 @@ static struct ceph_mds_session
> > > > > *register_session(struct ceph_mds_client *mdsc,
> > > > >               dout("%s: realloc to %d\n", __func__, newmax);
> > > > >            sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
> > > > > -        if (!sa)
> > > > > +        if (!sa) {
> > > > > +            err = -ENOMEM;
> > > > >                goto fail_realloc;
> > > > > +        }
> > > > >            if (mdsc->sessions) {
> > > > >                memcpy(sa, mdsc->sessions,
> > > > >                       mdsc->max_sessions * sizeof(void
> > > > > *));
> > > > > @@ -653,6 +658,13 @@ static struct ceph_mds_session
> > > > > *register_session(struct ceph_mds_client *mdsc,
> > > > >           INIT_LIST_HEAD(&s->s_cap_flushing);
> > > > >    +    err = percpu_counter_init(&s->i_caps_hit, 0, GFP_NOFS);
> > > > > +    if (err)
> > > > > +        goto fail_realloc;
> > > > > +    err = percpu_counter_init(&s->i_caps_mis, 0, GFP_NOFS);
> > > > > +    if (err)
> > > > > +        goto fail_init;
> > > > > +
> > > > >        mdsc->sessions[mds] = s;
> > > > >        atomic_inc(&mdsc->num_sessions);
> > > > >        refcount_inc(&s->s_ref);  /* one ref to sessions[], one
> > > > > to caller */
> > > > > @@ -662,6 +674,8 @@ static struct ceph_mds_session
> > > > > *register_session(struct ceph_mds_client *mdsc,
> > > > >           return s;
> > > > >    +fail_init:
> > > > > +    percpu_counter_destroy(&s->i_caps_hit);
> > > > >    fail_realloc:
> > > > >        kfree(s);
> > > > >        return ERR_PTR(-ENOMEM);
> > > > > diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> > > > > index dd1f417b90eb..ba74ff74c59c 100644
> > > > > --- a/fs/ceph/mds_client.h
> > > > > +++ b/fs/ceph/mds_client.h
> > > > > @@ -201,6 +201,9 @@ struct ceph_mds_session {
> > > > >           struct list_head  s_waiting;  /* waiting requests */
> > > > >        struct list_head  s_unsafe;   /* unsafe requests */
> > > > > +
> > > > > +    struct percpu_counter i_caps_hit;
> > > > > +    struct percpu_counter i_caps_mis;
> > > > >    };
> > > > >       /*
> > > > > diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
> > > > > index de56dee60540..4ce2f658e63d 100644
> > > > > --- a/fs/ceph/quota.c
> > > > > +++ b/fs/ceph/quota.c
> > > > > @@ -147,9 +147,14 @@ static struct inode
> > > > > *lookup_quotarealm_inode(struct ceph_mds_client *mdsc,
> > > > >            return NULL;
> > > > >        }
> > > > >        if (qri->inode) {
> > > > > +        struct ceph_inode_info *ci = ceph_inode(qri->inode);
> > > > > +        int ret;
> > > > > +
> > > > > +        ceph_caps_metric(ci, CEPH_STAT_CAP_INODE);
> > > > > +
> > > > >            /* get caps */
> > > > > -        int ret = __ceph_do_getattr(qri->inode, NULL,
> > > > > -                        CEPH_STAT_CAP_INODE, true);
> > > > > +        ret = __ceph_do_getattr(qri->inode, NULL,
> > > > > +                    CEPH_STAT_CAP_INODE, true);
> > > > >            if (ret >= 0)
> > > > >                in = qri->inode;
> > > > >            else
> > > > > diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> > > > > index 7af91628636c..3f4829222528 100644
> > > > > --- a/fs/ceph/super.h
> > > > > +++ b/fs/ceph/super.h
> > > > > @@ -641,6 +641,14 @@ static inline bool
> > > > > __ceph_is_any_real_caps(struct ceph_inode_info *ci)
> > > > >        return !RB_EMPTY_ROOT(&ci->i_caps);
> > > > >    }
> > > > >    +extern void __ceph_caps_metric(struct ceph_inode_info *ci, int
> > > > > mask);
> > > > > +static inline void ceph_caps_metric(struct ceph_inode_info *ci,
> > > > > int mask)
> > > > > +{
> > > > > +    spin_lock(&ci->i_ceph_lock);
> > > > > +    __ceph_caps_metric(ci, mask);
> > > > > +    spin_unlock(&ci->i_ceph_lock);
> > > > > +}
> > > > > +
> > > > >    extern int __ceph_caps_issued(struct ceph_inode_info *ci, int
> > > > > *implemented);
> > > > >    extern int __ceph_caps_issued_mask(struct ceph_inode_info *ci,
> > > > > int mask, int t);
> > > > >    extern int __ceph_caps_issued_other(struct ceph_inode_info *ci,
> > > > > @@ -927,6 +935,9 @@ extern int __ceph_do_getattr(struct inode
> > > > > *inode, struct page *locked_page,
> > > > >                     int mask, bool force);
> > > > >    static inline int ceph_do_getattr(struct inode *inode, int
> > > > > mask, bool force)
> > > > >    {
> > > > > +    struct ceph_inode_info *ci = ceph_inode(inode);
> > > > > +
> > > > > +    ceph_caps_metric(ci, mask);
> > > > >        return __ceph_do_getattr(inode, NULL, mask, force);
> > > > >    }
> > > > >    extern int ceph_permission(struct inode *inode, int mask);
> > > > > diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
> > > > > index d58fa14c1f01..ebd522edb0a8 100644
> > > > > --- a/fs/ceph/xattr.c
> > > > > +++ b/fs/ceph/xattr.c
> > > > > @@ -829,6 +829,7 @@ ssize_t __ceph_getxattr(struct inode *inode,
> > > > > const char *name, void *value,
> > > > >        struct ceph_vxattr *vxattr = NULL;
> > > > >        int req_mask;
> > > > >        ssize_t err;
> > > > > +    int ret = -1;
> > > > >           /* let's see if a virtual xattr was requested */
> > > > >        vxattr = ceph_match_vxattr(inode, name);
> > > > > @@ -856,7 +857,9 @@ ssize_t __ceph_getxattr(struct inode *inode,
> > > > > const char *name, void *value,
> > > > >           if (ci->i_xattrs.version == 0 ||
> > > > >            !((req_mask & CEPH_CAP_XATTR_SHARED) ||
> > > > > -          __ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1))) {
> > > > > +          (ret = __ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED,
> > > > > 1)))) {
> > > > > +        if (ret != -1)
> > > > > +            __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > >            spin_unlock(&ci->i_ceph_lock);
> > > > >               /* security module gets xattr while filling
> > > > > trace */
> > > > > @@ -871,6 +874,9 @@ ssize_t __ceph_getxattr(struct inode *inode,
> > > > > const char *name, void *value,
> > > > >            if (err)
> > > > >                return err;
> > > > >            spin_lock(&ci->i_ceph_lock);
> > > > > +    } else {
> > > > > +        if (ret != -1)
> > > > > +            __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > >        }
> > > > >           err = __build_xattrs(inode);
> > > > > @@ -907,19 +913,24 @@ ssize_t ceph_listxattr(struct dentry
> > > > > *dentry, char *names, size_t size)
> > > > >        struct ceph_inode_info *ci = ceph_inode(inode);
> > > > >        bool len_only = (size == 0);
> > > > >        u32 namelen;
> > > > > -    int err;
> > > > > +    int err, ret = -1;
> > > > >           spin_lock(&ci->i_ceph_lock);
> > > > >        dout("listxattr %p ver=%lld index_ver=%lld\n", inode,
> > > > >             ci->i_xattrs.version, ci->i_xattrs.index_version);
> > > > >           if (ci->i_xattrs.version == 0 ||
> > > > > -        !__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1)) {
> > > > > +        !(ret = __ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED,
> > > > > 1))) {
> > > > > +        if (ret != -1)
> > > > > +            __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > >            spin_unlock(&ci->i_ceph_lock);
> > > > >            err = ceph_do_getattr(inode,
> > > > > CEPH_STAT_CAP_XATTR, true);
> > > > >            if (err)
> > > > >                return err;
> > > > >            spin_lock(&ci->i_ceph_lock);
> > > > > +    } else {
> > > > > +        if (ret != -1)
> > > > > +            __ceph_caps_metric(ci, CEPH_CAP_XATTR_SHARED);
> > > > >        }
> > > > >           err = __build_xattrs(inode);