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authorYan, Zheng <zyan@redhat.com>2016-02-05 10:36:22 +0300
committerIlya Dryomov <idryomov@gmail.com>2016-07-28 03:55:37 +0300
commit51e9273796a57c08801f45580d3db3c51987a0cb (patch)
tree5eb35d4d7c0f44065b0fe17f0bb0a3c98202f215 /net
parent7627151ea30bce2051e3cb27d7bb2c30083f86a5 (diff)
downloadlinux-51e9273796a57c08801f45580d3db3c51987a0cb.tar.xz
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 <zyan@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/ceph/Makefile2
-rw-r--r--net/ceph/ceph_common.c2
-rw-r--r--net/ceph/string_table.c111
3 files changed, 114 insertions, 1 deletions
diff --git a/net/ceph/Makefile b/net/ceph/Makefile
index 958d9856912c..84cbed630c4b 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 55d2bfee16d7..bddfcf6f09c2 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 000000000000..ca53c8319209
--- /dev/null
+++ b/net/ceph/string_table.c
@@ -0,0 +1,111 @@
+#include <linux/slab.h>
+#include <linux/gfp.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/ceph/string_table.h>
+
+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);
+}