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>

1 files changed, 26 insertions, 7 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 6fbdc1a0afbe..36a8dc699448 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -148,11 +148,17 @@ void ceph_caps_finalize(struct ceph_mds_client *mdsc)
         spin_unlock(&mdsc->caps_list_lock);
 }
 
-void ceph_adjust_min_caps(struct ceph_mds_client *mdsc, int delta)
+void ceph_adjust_caps_max_min(struct ceph_mds_client *mdsc,
+                              struct ceph_mount_options *fsopt)
 {
         spin_lock(&mdsc->caps_list_lock);
-        mdsc->caps_min_count += delta;
-        BUG_ON(mdsc->caps_min_count < 0);
+        mdsc->caps_min_count = fsopt->max_readdir;
+        if (mdsc->caps_min_count < 1024)
+                mdsc->caps_min_count = 1024;
+        mdsc->caps_use_max = fsopt->caps_max;
+        if (mdsc->caps_use_max > 0 &&
+            mdsc->caps_use_max < mdsc->caps_min_count)
+                mdsc->caps_use_max = mdsc->caps_min_count;
         spin_unlock(&mdsc->caps_list_lock);
 }
 
@@ -272,6 +278,7 @@ int ceph_reserve_caps(struct ceph_mds_client *mdsc,
         if (!err) {
                 BUG_ON(have + alloc != need);
                 ctx->count = need;
+                ctx->used = 0;
         }
 
         spin_lock(&mdsc->caps_list_lock);
@@ -295,13 +302,24 @@ int ceph_reserve_caps(struct ceph_mds_client *mdsc,
 }
 
 void ceph_unreserve_caps(struct ceph_mds_client *mdsc,
-                        struct ceph_cap_reservation *ctx)
+                         struct ceph_cap_reservation *ctx)
 {
+        bool reclaim = false;
+        if (!ctx->count)
+                return;
+
         dout("unreserve caps ctx=%p count=%d\n", ctx, ctx->count);
         spin_lock(&mdsc->caps_list_lock);
         __ceph_unreserve_caps(mdsc, ctx->count);
         ctx->count = 0;
+
+        if (mdsc->caps_use_max > 0 &&
+            mdsc->caps_use_count > mdsc->caps_use_max)
+                reclaim = true;
         spin_unlock(&mdsc->caps_list_lock);
+
+        if (reclaim)
+                ceph_reclaim_caps_nr(mdsc, ctx->used);
 }
 
 struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
@@ -346,6 +364,7 @@ struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
         BUG_ON(list_empty(&mdsc->caps_list));
 
         ctx->count--;
+        ctx->used++;
         mdsc->caps_reserve_count--;
         mdsc->caps_use_count++;
 
@@ -500,12 +519,12 @@ static void __insert_cap_node(struct ceph_inode_info *ci,
 static void __cap_set_timeouts(struct ceph_mds_client *mdsc,
                                struct ceph_inode_info *ci)
 {
-        struct ceph_mount_options *ma = mdsc->fsc->mount_options;
+        struct ceph_mount_options *opt = mdsc->fsc->mount_options;
 
         ci->i_hold_caps_min = round_jiffies(jiffies +
-                                            ma->caps_wanted_delay_min * HZ);
+                                            opt->caps_wanted_delay_min * HZ);
         ci->i_hold_caps_max = round_jiffies(jiffies +
-                                            ma->caps_wanted_delay_max * HZ);
+                                            opt->caps_wanted_delay_max * HZ);
         dout("__cap_set_timeouts %p min %lu max %lu\n", &ci->vfs_inode,
              ci->i_hold_caps_min - jiffies, ci->i_hold_caps_max - jiffies);
 }