From 51e9273796a57c08801f45580d3db3c51987a0cb Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Fri, 5 Feb 2016 15:36:22 +0800 Subject: libceph: introduce reference counted string The data structure is for storing namesapce string. It allows namespace string to be shared between cephfs inodes with same layout. This data structure can also be referenced by OSD request. Signed-off-by: Yan, Zheng --- net/ceph/Makefile | 2 +- net/ceph/ceph_common.c | 2 + net/ceph/string_table.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 114 insertions(+), 1 deletion(-) create mode 100644 net/ceph/string_table.c (limited to 'net') diff --git a/net/ceph/Makefile b/net/ceph/Makefile index 958d9856..84cbed6 100644 --- a/net/ceph/Makefile +++ b/net/ceph/Makefile @@ -11,5 +11,5 @@ libceph-y := ceph_common.o messenger.o msgpool.o buffer.o pagelist.o \ crypto.o armor.o \ auth_x.o \ ceph_fs.o ceph_strings.o ceph_hash.o \ - pagevec.o snapshot.o + pagevec.o snapshot.o string_table.o diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c index 55d2bfe..bddfcf6 100644 --- a/net/ceph/ceph_common.c +++ b/net/ceph/ceph_common.c @@ -747,6 +747,8 @@ out: static void __exit exit_ceph_lib(void) { dout("exit_ceph_lib\n"); + WARN_ON(!ceph_strings_empty()); + ceph_osdc_cleanup(); ceph_msgr_exit(); ceph_crypto_shutdown(); diff --git a/net/ceph/string_table.c b/net/ceph/string_table.c new file mode 100644 index 0000000..ca53c83 --- /dev/null +++ b/net/ceph/string_table.c @@ -0,0 +1,111 @@ +#include +#include +#include +#include +#include + +static DEFINE_SPINLOCK(string_tree_lock); +static struct rb_root string_tree = RB_ROOT; + +struct ceph_string *ceph_find_or_create_string(const char* str, size_t len) +{ + struct ceph_string *cs, *exist; + struct rb_node **p, *parent; + int ret; + + exist = NULL; + spin_lock(&string_tree_lock); + p = &string_tree.rb_node; + while (*p) { + exist = rb_entry(*p, struct ceph_string, node); + ret = ceph_compare_string(exist, str, len); + if (ret > 0) + p = &(*p)->rb_left; + else if (ret < 0) + p = &(*p)->rb_right; + else + break; + exist = NULL; + } + if (exist && !kref_get_unless_zero(&exist->kref)) { + rb_erase(&exist->node, &string_tree); + RB_CLEAR_NODE(&exist->node); + exist = NULL; + } + spin_unlock(&string_tree_lock); + if (exist) + return exist; + + cs = kmalloc(sizeof(*cs) + len + 1, GFP_NOFS); + if (!cs) + return NULL; + + kref_init(&cs->kref); + cs->len = len; + memcpy(cs->str, str, len); + cs->str[len] = 0; + +retry: + exist = NULL; + parent = NULL; + p = &string_tree.rb_node; + spin_lock(&string_tree_lock); + while (*p) { + parent = *p; + exist = rb_entry(*p, struct ceph_string, node); + ret = ceph_compare_string(exist, str, len); + if (ret > 0) + p = &(*p)->rb_left; + else if (ret < 0) + p = &(*p)->rb_right; + else + break; + exist = NULL; + } + ret = 0; + if (!exist) { + rb_link_node(&cs->node, parent, p); + rb_insert_color(&cs->node, &string_tree); + } else if (!kref_get_unless_zero(&exist->kref)) { + rb_erase(&exist->node, &string_tree); + RB_CLEAR_NODE(&exist->node); + ret = -EAGAIN; + } + spin_unlock(&string_tree_lock); + if (ret == -EAGAIN) + goto retry; + + if (exist) { + kfree(cs); + cs = exist; + } + + return cs; +} +EXPORT_SYMBOL(ceph_find_or_create_string); + +static void ceph_free_string(struct rcu_head *head) +{ + struct ceph_string *cs = container_of(head, struct ceph_string, rcu); + kfree(cs); +} + +void ceph_release_string(struct kref *ref) +{ + struct ceph_string *cs = container_of(ref, struct ceph_string, kref); + + spin_lock(&string_tree_lock); + if (!RB_EMPTY_NODE(&cs->node)) { + rb_erase(&cs->node, &string_tree); + RB_CLEAR_NODE(&cs->node); + } + spin_unlock(&string_tree_lock); + + call_rcu(&cs->rcu, ceph_free_string); +} +EXPORT_SYMBOL(ceph_release_string); + +bool ceph_strings_empty(void) +{ + return RB_EMPTY_ROOT(&string_tree); +} -- cgit v1.1