ceph: eliminate session->s_trim_caps

It's only used to keep count of caps being trimmed, but that requires
that we hold the session->s_mutex to prevent multiple trimming
operations from running concurrently.

We can achieve the same effect using an integer on the stack, which
allows us to (eventually) not need the s_mutex.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 5bfbff8..959dcf2 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -639,7 +639,6 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
        s->s_renew_seq = 0;
        INIT_LIST_HEAD(&s->s_caps);
        s->s_nr_caps = 0;
-       s->s_trim_caps = 0;
        refcount_set(&s->s_ref, 1);
        INIT_LIST_HEAD(&s->s_waiting);
        INIT_LIST_HEAD(&s->s_unsafe);
@@ -1722,11 +1721,11 @@ out:
  */
 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
 {
-       struct ceph_mds_session *session = arg;
+       int *remaining = arg;
        struct ceph_inode_info *ci = ceph_inode(inode);
        int used, wanted, oissued, mine;
 
-       if (session->s_trim_caps <= 0)
+       if (*remaining <= 0)
                return -1;
 
        spin_lock(&ci->i_ceph_lock);
@@ -1763,7 +1762,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
        if (oissued) {
                /* we aren't the only cap.. just remove us */
                __ceph_remove_cap(cap, true);
-               session->s_trim_caps--;
+               (*remaining)--;
        } else {
                struct dentry *dentry;
                /* try dropping referring dentries */
@@ -1775,7 +1774,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
                        d_prune_aliases(inode);
                        count = atomic_read(&inode->i_count);
                        if (count == 1)
-                               session->s_trim_caps--;
+                               (*remaining)--;
                        dout("trim_caps_cb %p cap %p pruned, count now %d\n",
                             inode, cap, count);
                } else {
@@ -1801,12 +1800,12 @@ int ceph_trim_caps(struct ceph_mds_client *mdsc,
        dout("trim_caps mds%d start: %d / %d, trim %d\n",
             session->s_mds, session->s_nr_caps, max_caps, trim_caps);
        if (trim_caps > 0) {
-               session->s_trim_caps = trim_caps;
-               ceph_iterate_session_caps(session, trim_caps_cb, session);
+               int remaining = trim_caps;
+
+               ceph_iterate_session_caps(session, trim_caps_cb, &remaining);
                dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
                     session->s_mds, session->s_nr_caps, max_caps,
-                       trim_caps - session->s_trim_caps);
-               session->s_trim_caps = 0;
+                       trim_caps - remaining);
        }
 
        ceph_flush_cap_releases(mdsc, session);

diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 810fd86..5cd131b 100644 (file)
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -176,7 +176,7 @@ struct ceph_mds_session {
        spinlock_t        s_cap_lock;
        struct list_head  s_caps;     /* all caps issued by this session */
        struct ceph_cap  *s_cap_iterator;
-       int               s_nr_caps, s_trim_caps;
+       int               s_nr_caps;
        int               s_num_cap_releases;
        int               s_cap_reconnect;
        int               s_readonly;