mirror of
https://github.com/torvalds/linux.git
synced 2024-11-12 07:01:57 +00:00
51e9273796
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>
112 lines
2.3 KiB
C
112 lines
2.3 KiB
C
#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);
|
|
}
|