ceph: add mount option to limit caps count
If number of caps exceed the limit, ceph_trim_dentires() also trim
dentries with valid leases. Trimming dentry releases references to
associated inode, which may evict inode and release caps.
By default, there is no limit for caps count.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index eba2835..a8f4298 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1224,6 +1224,7 @@ enum {
struct ceph_lease_walk_control {
bool dir_lease;
+ bool expire_dir_lease;
unsigned long nr_to_scan;
unsigned long dir_lease_ttl;
};
@@ -1345,7 +1346,13 @@ static int __dir_lease_check(struct dentry *dentry, void *arg)
/* Move dentry to tail of dir lease list if we don't want
* to delete it. So dentries in the list are checked in a
* round robin manner */
- return TOUCH;
+ if (!lwc->expire_dir_lease)
+ return TOUCH;
+ if (dentry->d_lockref.count > 0 ||
+ (di->flags & CEPH_DENTRY_REFERENCED))
+ return TOUCH;
+ /* invalidate dir lease */
+ di->lease_shared_gen = 0;
}
return DELETE;
}
@@ -1353,8 +1360,17 @@ static int __dir_lease_check(struct dentry *dentry, void *arg)
int ceph_trim_dentries(struct ceph_mds_client *mdsc)
{
struct ceph_lease_walk_control lwc;
+ unsigned long count;
unsigned long freed;
+ spin_lock(&mdsc->caps_list_lock);
+ if (mdsc->caps_use_max > 0 &&
+ mdsc->caps_use_count > mdsc->caps_use_max)
+ count = mdsc->caps_use_count - mdsc->caps_use_max;
+ else
+ count = 0;
+ spin_unlock(&mdsc->caps_list_lock);
+
lwc.dir_lease = false;
lwc.nr_to_scan = CEPH_CAPS_PER_RELEASE * 2;
freed = __dentry_leases_walk(mdsc, &lwc, __dentry_lease_check);
@@ -1365,6 +1381,8 @@ int ceph_trim_dentries(struct ceph_mds_client *mdsc)
lwc.nr_to_scan = CEPH_CAPS_PER_RELEASE;
lwc.dir_lease = true;
+ lwc.expire_dir_lease = freed < count;
+ lwc.dir_lease_ttl = mdsc->fsc->mount_options->caps_wanted_delay_max * HZ;
freed +=__dentry_leases_walk(mdsc, &lwc, __dir_lease_check);
if (!lwc.nr_to_scan) /* more to check */
return -EAGAIN;