From 75c9627efb7288e1725e9903ea275cc6b5992f17 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Thu, 14 Dec 2017 15:11:09 +0800 Subject: ceph: map snapid to anonymous bdev ID ceph_getattr() return zero dev ID for head inodes and set dev ID to snapid directly for snaphost inodes. This is not good because userspace utilities may consider device ID of 0 as invalid, snapid may conflict with other device's ID. This patch introduces "snapids to anonymous bdev IDs" map. we create a new mapping when we see a snapid for the first time. we trim unused mapping after it is ilde for 5 minutes. Link: http://tracker.ceph.com/issues/22353 Signed-off-by: "Yan, Zheng" Acked-by: Jeff Layton Signed-off-by: Ilya Dryomov --- fs/ceph/snap.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 154 insertions(+), 2 deletions(-) (limited to 'fs/ceph/snap.c') diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index dfc25ceeffed..89aa37fa0f84 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -3,12 +3,13 @@ #include #include - #include "super.h" #include "mds_client.h" - #include +/* unused map expires after 5 minutes */ +#define CEPH_SNAPID_MAP_TIMEOUT (5 * 60 * HZ) + /* * Snapshots in ceph are driven in large part by cooperation from the * client. In contrast to local file systems or file servers that @@ -989,3 +990,154 @@ out: up_write(&mdsc->snap_rwsem); return; } + +struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc, + u64 snap) +{ + struct ceph_snapid_map *sm, *exist; + struct rb_node **p, *parent; + int ret; + + exist = NULL; + spin_lock(&mdsc->snapid_map_lock); + p = &mdsc->snapid_map_tree.rb_node; + while (*p) { + exist = rb_entry(*p, struct ceph_snapid_map, node); + if (snap > exist->snap) { + p = &(*p)->rb_left; + } else if (snap < exist->snap) { + p = &(*p)->rb_right; + } else { + if (atomic_inc_return(&exist->ref) == 1) + list_del_init(&exist->lru); + break; + } + exist = NULL; + } + spin_unlock(&mdsc->snapid_map_lock); + if (exist) { + dout("found snapid map %llx -> %x\n", exist->snap, exist->dev); + return exist; + } + + sm = kmalloc(sizeof(*sm), GFP_NOFS); + if (!sm) + return NULL; + + ret = get_anon_bdev(&sm->dev); + if (ret < 0) { + kfree(sm); + return NULL; + } + + INIT_LIST_HEAD(&sm->lru); + atomic_set(&sm->ref, 1); + sm->snap = snap; + + exist = NULL; + parent = NULL; + p = &mdsc->snapid_map_tree.rb_node; + spin_lock(&mdsc->snapid_map_lock); + while (*p) { + parent = *p; + exist = rb_entry(*p, struct ceph_snapid_map, node); + if (snap > exist->snap) + p = &(*p)->rb_left; + else if (snap < exist->snap) + p = &(*p)->rb_right; + else + break; + exist = NULL; + } + if (exist) { + if (atomic_inc_return(&exist->ref) == 1) + list_del_init(&exist->lru); + } else { + rb_link_node(&sm->node, parent, p); + rb_insert_color(&sm->node, &mdsc->snapid_map_tree); + } + spin_unlock(&mdsc->snapid_map_lock); + if (exist) { + free_anon_bdev(sm->dev); + kfree(sm); + dout("found snapid map %llx -> %x\n", exist->snap, exist->dev); + return exist; + } + + dout("create snapid map %llx -> %x\n", sm->snap, sm->dev); + return sm; +} + +void ceph_put_snapid_map(struct ceph_mds_client* mdsc, + struct ceph_snapid_map *sm) +{ + if (!sm) + return; + if (atomic_dec_and_lock(&sm->ref, &mdsc->snapid_map_lock)) { + if (!RB_EMPTY_NODE(&sm->node)) { + sm->last_used = jiffies; + list_add_tail(&sm->lru, &mdsc->snapid_map_lru); + spin_unlock(&mdsc->snapid_map_lock); + } else { + /* already cleaned up by + * ceph_cleanup_snapid_map() */ + spin_unlock(&mdsc->snapid_map_lock); + kfree(sm); + } + } +} + +void ceph_trim_snapid_map(struct ceph_mds_client *mdsc) +{ + struct ceph_snapid_map *sm; + unsigned long now; + LIST_HEAD(to_free); + + spin_lock(&mdsc->snapid_map_lock); + now = jiffies; + + while (!list_empty(&mdsc->snapid_map_lru)) { + sm = list_first_entry(&mdsc->snapid_map_lru, + struct ceph_snapid_map, lru); + if (time_after(sm->last_used + CEPH_SNAPID_MAP_TIMEOUT, now)) + break; + + rb_erase(&sm->node, &mdsc->snapid_map_tree); + list_move(&sm->lru, &to_free); + } + spin_unlock(&mdsc->snapid_map_lock); + + while (!list_empty(&to_free)) { + sm = list_first_entry(&to_free, struct ceph_snapid_map, lru); + list_del(&sm->lru); + dout("trim snapid map %llx -> %x\n", sm->snap, sm->dev); + free_anon_bdev(sm->dev); + kfree(sm); + } +} + +void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc) +{ + struct ceph_snapid_map *sm; + struct rb_node *p; + LIST_HEAD(to_free); + + spin_lock(&mdsc->snapid_map_lock); + while ((p = rb_first(&mdsc->snapid_map_tree))) { + sm = rb_entry(p, struct ceph_snapid_map, node); + rb_erase(p, &mdsc->snapid_map_tree); + RB_CLEAR_NODE(p); + list_move(&sm->lru, &to_free); + } + spin_unlock(&mdsc->snapid_map_lock); + + while (!list_empty(&to_free)) { + sm = list_first_entry(&to_free, struct ceph_snapid_map, lru); + list_del(&sm->lru); + free_anon_bdev(sm->dev); + if (WARN_ON_ONCE(atomic_read(&sm->ref))) { + pr_err("snapid map %llx -> %x still in use\n", + sm->snap, sm->dev); + } + } +} -- cgit v1.2.3