staging: lustre: convert osc_quota hash to rhashtable

As this is indexed by an integer, an extensible array
or extensible bitmap would be better.
If/when xarray lands, we should change to use that.

For now, just a simple conversion to rhashtable.

When removing an entry, we need to hold rcu_read_lock()
across the lookup and remove in case we race with another thread
performing a removal.  This means we need to use call_rcu()
to free the quota info so we need an rcu_head in there, which
unfortunately doubles the size of the structure.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h
index 0d0420e2795afbbfa28d66af34ae02399785e6ef..fe21987a3f9f68b7f735d9e0864df0efc73abc48 100644 (file)
--- a/drivers/staging/lustre/lustre/include/obd.h
+++ b/drivers/staging/lustre/lustre/include/obd.h
@@ -333,7 +333,7 @@ struct client_obd {
        void                *cl_writeback_work;
        void                    *cl_lru_work;
        /* hash tables for osc_quota_info */
-       struct cfs_hash       *cl_quota_hash[MAXQUOTAS];
+       struct rhashtable       cl_quota_hash[MAXQUOTAS];
 };
 
 #define obd2cli_tgt(obd) ((char *)(obd)->u.cli.cl_target_uuid.uuid)

diff --git a/drivers/staging/lustre/lustre/osc/osc_internal.h b/drivers/staging/lustre/lustre/osc/osc_internal.h
index 32db150fd42ec37aa80b3f736c07a4f43cec31bc..1c8ba4ad6e7f8364842963548a014caf8ee5c4c5 100644 (file)
--- a/drivers/staging/lustre/lustre/osc/osc_internal.h
+++ b/drivers/staging/lustre/lustre/osc/osc_internal.h
@@ -188,8 +188,9 @@ extern struct lu_kmem_descr osc_caches[];
 extern struct kmem_cache *osc_quota_kmem;
 struct osc_quota_info {
        /** linkage for quota hash table */
-       struct hlist_node oqi_hash;
-       u32       oqi_id;
+       struct rhash_head oqi_hash;
+       u32               oqi_id;
+       struct rcu_head   rcu;
 };
 
 int osc_quota_setup(struct obd_device *obd);

diff --git a/drivers/staging/lustre/lustre/osc/osc_quota.c b/drivers/staging/lustre/lustre/osc/osc_quota.c
index ce1731dc604fe14a0a80eb24f7ae3ba2c0a5603d..723ec2fb18bf0b0cf5cc729dc630cec94c5bca16 100644 (file)
--- a/drivers/staging/lustre/lustre/osc/osc_quota.c
+++ b/drivers/staging/lustre/lustre/osc/osc_quota.c
@@ -27,6 +27,13 @@
 #include <obd_class.h>
 #include "osc_internal.h"
 
+static const struct rhashtable_params quota_hash_params = {
+       .key_len        = sizeof(u32),
+       .key_offset     = offsetof(struct osc_quota_info, oqi_id),
+       .head_offset    = offsetof(struct osc_quota_info, oqi_hash),
+       .automatic_shrinking = true,
+};
+
 static inline struct osc_quota_info *osc_oqi_alloc(u32 id)
 {
        struct osc_quota_info *oqi;
@@ -45,9 +52,10 @@ int osc_quota_chkdq(struct client_obd *cli, const unsigned int qid[])
        for (type = 0; type < MAXQUOTAS; type++) {
                struct osc_quota_info *oqi;
 
-               oqi = cfs_hash_lookup(cli->cl_quota_hash[type], &qid[type]);
+               oqi = rhashtable_lookup_fast(&cli->cl_quota_hash[type], &qid[type],
+                                            quota_hash_params);
                if (oqi) {
-                       /* do not try to access oqi here, it could have been
+                       /* Must not access oqi here, it could have been
                         * freed by osc_quota_setdq()
                         */
 
@@ -63,6 +71,14 @@ int osc_quota_chkdq(struct client_obd *cli, const unsigned int qid[])
        return QUOTA_OK;
 }
 
+static void osc_quota_free(struct rcu_head *head)
+{
+       struct osc_quota_info *oqi = container_of(head, struct osc_quota_info, rcu);
+
+       kmem_cache_free(osc_quota_kmem, oqi);
+}
+
+
 #define MD_QUOTA_FLAG(type) ((type == USRQUOTA) ? OBD_MD_FLUSRQUOTA \
                                                : OBD_MD_FLGRPQUOTA)
 #define FL_QUOTA_FLAG(type) ((type == USRQUOTA) ? OBD_FL_NO_USRQUOTA \
@@ -84,11 +100,14 @@ int osc_quota_setdq(struct client_obd *cli, const unsigned int qid[],
                        continue;
 
                /* lookup the ID in the per-type hash table */
-               oqi = cfs_hash_lookup(cli->cl_quota_hash[type], &qid[type]);
+               rcu_read_lock();
+               oqi = rhashtable_lookup_fast(&cli->cl_quota_hash[type], &qid[type],
+                                            quota_hash_params);
                if ((flags & FL_QUOTA_FLAG(type)) != 0) {
                        /* This ID is getting close to its quota limit, let's
                         * switch to sync I/O
                         */
+                       rcu_read_unlock();
                        if (oqi)
                                continue;
 
@@ -98,12 +117,16 @@ int osc_quota_setdq(struct client_obd *cli, const unsigned int qid[],
                                break;
                        }
 
-                       rc = cfs_hash_add_unique(cli->cl_quota_hash[type],
-                                                &qid[type], &oqi->oqi_hash);
+                       rc = rhashtable_lookup_insert_fast(&cli->cl_quota_hash[type],
+                                                          &oqi->oqi_hash, quota_hash_params);
                        /* race with others? */
-                       if (rc == -EALREADY) {
-                               rc = 0;
+                       if (rc) {
                                kmem_cache_free(osc_quota_kmem, oqi);
+                               if (rc != -EEXIST) {
+                                       rc = -ENOMEM;
+                                       break;
+                               }
+                               rc = 0;
                        }
 
                        CDEBUG(D_QUOTA, "%s: setdq to insert for %s %d (%d)\n",
@@ -114,14 +137,14 @@ int osc_quota_setdq(struct client_obd *cli, const unsigned int qid[],
                        /* This ID is now off the hook, let's remove it from
                         * the hash table
                         */
-                       if (!oqi)
+                       if (!oqi) {
+                               rcu_read_unlock();
                                continue;
-
-                       oqi = cfs_hash_del_key(cli->cl_quota_hash[type],
-                                              &qid[type]);
-                       if (oqi)
-                               kmem_cache_free(osc_quota_kmem, oqi);
-
+                       }
+                       if (rhashtable_remove_fast(&cli->cl_quota_hash[type],
+                                                  &oqi->oqi_hash, quota_hash_params) == 0)
+                               call_rcu(&oqi->rcu, osc_quota_free);
+                       rcu_read_unlock();
                        CDEBUG(D_QUOTA, "%s: setdq to remove for %s %d (%p)\n",
                               cli_name(cli),
                               type == USRQUOTA ? "user" : "group",
@@ -132,93 +155,21 @@ int osc_quota_setdq(struct client_obd *cli, const unsigned int qid[],
        return rc;
 }
 
-/*
- * Hash operations for uid/gid <-> osc_quota_info
- */
-static unsigned int
-oqi_hashfn(struct cfs_hash *hs, const void *key, unsigned int mask)
-{
-       return cfs_hash_u32_hash(*((__u32 *)key), mask);
-}
-
-static int
-oqi_keycmp(const void *key, struct hlist_node *hnode)
-{
-       struct osc_quota_info *oqi;
-       u32 uid;
-
-       LASSERT(key);
-       uid = *((u32 *)key);
-       oqi = hlist_entry(hnode, struct osc_quota_info, oqi_hash);
-
-       return uid == oqi->oqi_id;
-}
-
-static void *
-oqi_key(struct hlist_node *hnode)
-{
-       struct osc_quota_info *oqi;
-
-       oqi = hlist_entry(hnode, struct osc_quota_info, oqi_hash);
-       return &oqi->oqi_id;
-}
-
-static void *
-oqi_object(struct hlist_node *hnode)
-{
-       return hlist_entry(hnode, struct osc_quota_info, oqi_hash);
-}
-
-static void
-oqi_get(struct cfs_hash *hs, struct hlist_node *hnode)
-{
-}
-
-static void
-oqi_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
-{
-}
-
 static void
-oqi_exit(struct cfs_hash *hs, struct hlist_node *hnode)
+oqi_exit(void *vquota, void *data)
 {
-       struct osc_quota_info *oqi;
-
-       oqi = hlist_entry(hnode, struct osc_quota_info, oqi_hash);
+       struct osc_quota_info *oqi = vquota;
 
-       kmem_cache_free(osc_quota_kmem, oqi);
+       osc_quota_free(&oqi->rcu);
 }
 
-#define HASH_QUOTA_BKT_BITS 5
-#define HASH_QUOTA_CUR_BITS 5
-#define HASH_QUOTA_MAX_BITS 15
-
-static struct cfs_hash_ops quota_hash_ops = {
-       .hs_hash        = oqi_hashfn,
-       .hs_keycmp      = oqi_keycmp,
-       .hs_key         = oqi_key,
-       .hs_object      = oqi_object,
-       .hs_get         = oqi_get,
-       .hs_put_locked  = oqi_put_locked,
-       .hs_exit        = oqi_exit,
-};
-
 int osc_quota_setup(struct obd_device *obd)
 {
        struct client_obd *cli = &obd->u.cli;
        int i, type;
 
        for (type = 0; type < MAXQUOTAS; type++) {
-               cli->cl_quota_hash[type] = cfs_hash_create("QUOTA_HASH",
-                                                          HASH_QUOTA_CUR_BITS,
-                                                          HASH_QUOTA_MAX_BITS,
-                                                          HASH_QUOTA_BKT_BITS,
-                                                          0,
-                                                          CFS_HASH_MIN_THETA,
-                                                          CFS_HASH_MAX_THETA,
-                                                          &quota_hash_ops,
-                                                          CFS_HASH_DEFAULT);
-               if (!cli->cl_quota_hash[type])
+               if (rhashtable_init(&cli->cl_quota_hash[type], &quota_hash_params) != 0)
                        break;
        }
 
@@ -226,7 +177,7 @@ int osc_quota_setup(struct obd_device *obd)
                return 0;
 
        for (i = 0; i < type; i++)
-               cfs_hash_putref(cli->cl_quota_hash[i]);
+               rhashtable_destroy(&cli->cl_quota_hash[i]);
 
        return -ENOMEM;
 }
@@ -237,7 +188,8 @@ int osc_quota_cleanup(struct obd_device *obd)
        int type;
 
        for (type = 0; type < MAXQUOTAS; type++)
-               cfs_hash_putref(cli->cl_quota_hash[type]);
+               rhashtable_free_and_destroy(&cli->cl_quota_hash[type],
+                                           oqi_exit, NULL);
 
        return 0;
 }