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);
 }