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LU-2282 obdclass: Slightly increase the size of lu_keys[]
[fs/lustre-release.git] / lustre / obdclass / lu_object.c
index fe1d9fc..74c1cc9 100644 (file)
@@ -75,11 +75,32 @@ void lu_object_put(const struct lu_env *env, struct lu_object *o)
         struct lu_site          *site;
         struct lu_object        *orig;
         cfs_hash_bd_t            bd;
+       const struct lu_fid     *fid;
 
         top  = o->lo_header;
         site = o->lo_dev->ld_site;
         orig = o;
 
+       /*
+        * till we have full fids-on-OST implemented anonymous objects
+        * are possible in OSP. such an object isn't listed in the site
+        * so we should not remove it from the site.
+        */
+       fid = lu_object_fid(o);
+       if (fid_is_zero(fid)) {
+               LASSERT(top->loh_hash.next == NULL
+                       && top->loh_hash.pprev == NULL);
+               LASSERT(cfs_list_empty(&top->loh_lru));
+               if (!cfs_atomic_dec_and_test(&top->loh_ref))
+                       return;
+               cfs_list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
+                       if (o->lo_ops->loo_object_release != NULL)
+                               o->lo_ops->loo_object_release(env, o);
+               }
+               lu_object_free(env, orig);
+               return;
+       }
+
         cfs_hash_bd_get(site->ls_obj_hash, &top->loh_fid, &bd);
         bkt = cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
 
@@ -135,6 +156,18 @@ void lu_object_put(const struct lu_env *env, struct lu_object *o)
 EXPORT_SYMBOL(lu_object_put);
 
 /**
+ * Put object and don't keep in cache. This is temporary solution for
+ * multi-site objects when its layering is not constant.
+ */
+void lu_object_put_nocache(const struct lu_env *env, struct lu_object *o)
+{
+       cfs_set_bit(LU_OBJECT_HEARD_BANSHEE,
+                   &o->lo_header->loh_flags);
+       return lu_object_put(env, o);
+}
+EXPORT_SYMBOL(lu_object_put_nocache);
+
+/**
  * Allocate new object.
  *
  * This follows object creation protocol, described in the comment within
@@ -886,6 +919,23 @@ cfs_hash_ops_t lu_site_hash_ops = {
         .hs_put_locked  = lu_obj_hop_put_locked,
 };
 
+void lu_dev_add_linkage(struct lu_site *s, struct lu_device *d)
+{
+       cfs_spin_lock(&s->ls_ld_lock);
+       if (cfs_list_empty(&d->ld_linkage))
+               cfs_list_add(&d->ld_linkage, &s->ls_ld_linkage);
+       cfs_spin_unlock(&s->ls_ld_lock);
+}
+EXPORT_SYMBOL(lu_dev_add_linkage);
+
+void lu_dev_del_linkage(struct lu_site *s, struct lu_device *d)
+{
+       cfs_spin_lock(&s->ls_ld_lock);
+       cfs_list_del_init(&d->ld_linkage);
+       cfs_spin_unlock(&s->ls_ld_lock);
+}
+EXPORT_SYMBOL(lu_dev_del_linkage);
+
 /**
  * Initialize site \a s, with \a d as the top level device.
  */
@@ -964,9 +1014,7 @@ int lu_site_init(struct lu_site *s, struct lu_device *top)
         CFS_INIT_LIST_HEAD(&s->ls_ld_linkage);
         cfs_spin_lock_init(&s->ls_ld_lock);
 
-        cfs_spin_lock(&s->ls_ld_lock);
-        cfs_list_add(&top->ld_linkage, &s->ls_ld_linkage);
-        cfs_spin_unlock(&s->ls_ld_lock);
+       lu_dev_add_linkage(s, top);
 
         RETURN(0);
 }
@@ -1198,15 +1246,6 @@ void lu_stack_fini(const struct lu_env *env, struct lu_device *top)
         /* purge again. */
         lu_site_purge(env, site, ~0);
 
-        if (!cfs_hash_is_empty(site->ls_obj_hash)) {
-                /*
-                 * Uh-oh, objects still exist.
-                 */
-                LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, D_ERROR, NULL);
-
-                lu_site_print(env, site, &msgdata, lu_cdebug_printer);
-        }
-
         for (scan = top; scan != NULL; scan = next) {
                 const struct lu_device_type *ldt = scan->ld_type;
                 struct obd_type             *type;
@@ -1225,12 +1264,12 @@ enum {
         /**
          * Maximal number of tld slots.
          */
-        LU_CONTEXT_KEY_NR = 32
+        LU_CONTEXT_KEY_NR = 40
 };
 
 static struct lu_context_key *lu_keys[LU_CONTEXT_KEY_NR] = { NULL, };
 
-static cfs_spinlock_t lu_keys_guard = CFS_SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(lu_keys_guard);
 
 /**
  * Global counter incremented whenever key is registered, unregistered,
@@ -1284,13 +1323,14 @@ static void key_fini(struct lu_context *ctx, int index)
                 key->lct_fini(ctx, key, ctx->lc_value[index]);
                 lu_ref_del(&key->lct_reference, "ctx", ctx);
                 cfs_atomic_dec(&key->lct_used);
-                LASSERT(key->lct_owner != NULL);
-                if (!(ctx->lc_tags & LCT_NOREF)) {
-                        LASSERT(cfs_module_refcount(key->lct_owner) > 0);
-                        cfs_module_put(key->lct_owner);
-                }
-                ctx->lc_value[index] = NULL;
-        }
+
+               LASSERT(key->lct_owner != NULL);
+               if ((ctx->lc_tags & LCT_NOREF) == 0) {
+                       LINVRNT(cfs_module_refcount(key->lct_owner) > 0);
+                       cfs_module_put(key->lct_owner);
+               }
+               ctx->lc_value[index] = NULL;
+       }
 }
 
 /**
@@ -1455,17 +1495,16 @@ EXPORT_SYMBOL(lu_context_key_revive);
 
 static void keys_fini(struct lu_context *ctx)
 {
-        int i;
+       int     i;
 
-        cfs_spin_lock(&lu_keys_guard);
-        if (ctx->lc_value != NULL) {
-                for (i = 0; i < ARRAY_SIZE(lu_keys); ++i)
-                        key_fini(ctx, i);
-                OBD_FREE(ctx->lc_value,
-                         ARRAY_SIZE(lu_keys) * sizeof ctx->lc_value[0]);
-                ctx->lc_value = NULL;
-        }
-        cfs_spin_unlock(&lu_keys_guard);
+       if (ctx->lc_value == NULL)
+               return;
+
+       for (i = 0; i < ARRAY_SIZE(lu_keys); ++i)
+               key_fini(ctx, i);
+
+       OBD_FREE(ctx->lc_value, ARRAY_SIZE(lu_keys) * sizeof ctx->lc_value[0]);
+       ctx->lc_value = NULL;
 }
 
 static int keys_fill(struct lu_context *ctx)
@@ -1514,17 +1553,11 @@ static int keys_fill(struct lu_context *ctx)
 
 static int keys_init(struct lu_context *ctx)
 {
-        int result;
+       OBD_ALLOC(ctx->lc_value, ARRAY_SIZE(lu_keys) * sizeof ctx->lc_value[0]);
+       if (likely(ctx->lc_value != NULL))
+               return keys_fill(ctx);
 
-        OBD_ALLOC(ctx->lc_value, ARRAY_SIZE(lu_keys) * sizeof ctx->lc_value[0]);
-        if (likely(ctx->lc_value != NULL))
-                result = keys_fill(ctx);
-        else
-                result = -ENOMEM;
-
-        if (result != 0)
-                keys_fini(ctx);
-        return result;
+       return -ENOMEM;
 }
 
 /**
@@ -1532,6 +1565,8 @@ static int keys_init(struct lu_context *ctx)
  */
 int lu_context_init(struct lu_context *ctx, __u32 tags)
 {
+       int     rc;
+
         memset(ctx, 0, sizeof *ctx);
         ctx->lc_state = LCS_INITIALIZED;
         ctx->lc_tags = tags;
@@ -1539,9 +1574,15 @@ int lu_context_init(struct lu_context *ctx, __u32 tags)
                 cfs_spin_lock(&lu_keys_guard);
                 cfs_list_add(&ctx->lc_remember, &lu_context_remembered);
                 cfs_spin_unlock(&lu_keys_guard);
-        } else
-                CFS_INIT_LIST_HEAD(&ctx->lc_remember);
-        return keys_init(ctx);
+       } else {
+               CFS_INIT_LIST_HEAD(&ctx->lc_remember);
+       }
+
+       rc = keys_init(ctx);
+       if (rc != 0)
+               lu_context_fini(ctx);
+
+       return rc;
 }
 EXPORT_SYMBOL(lu_context_init);
 
@@ -1550,12 +1591,19 @@ EXPORT_SYMBOL(lu_context_init);
  */
 void lu_context_fini(struct lu_context *ctx)
 {
-        LINVRNT(ctx->lc_state == LCS_INITIALIZED || ctx->lc_state == LCS_LEFT);
-        ctx->lc_state = LCS_FINALIZED;
-        keys_fini(ctx);
-        cfs_spin_lock(&lu_keys_guard);
-        cfs_list_del_init(&ctx->lc_remember);
-        cfs_spin_unlock(&lu_keys_guard);
+       LINVRNT(ctx->lc_state == LCS_INITIALIZED || ctx->lc_state == LCS_LEFT);
+       ctx->lc_state = LCS_FINALIZED;
+
+       if ((ctx->lc_tags & LCT_REMEMBER) == 0) {
+               LASSERT(cfs_list_empty(&ctx->lc_remember));
+               keys_fini(ctx);
+
+       } else { /* could race with key degister */
+               cfs_spin_lock(&lu_keys_guard);
+               keys_fini(ctx);
+               cfs_list_del_init(&ctx->lc_remember);
+               cfs_spin_unlock(&lu_keys_guard);
+       }
 }
 EXPORT_SYMBOL(lu_context_fini);
 
@@ -1749,6 +1797,24 @@ static void lu_site_stats_get(cfs_hash_t *hs,
 
 #ifdef __KERNEL__
 
+/*
+ * There exists a potential lock inversion deadlock scenario when using
+ * Lustre on top of ZFS. This occurs between one of ZFS's
+ * buf_hash_table.ht_lock's, and Lustre's lu_sites_guard lock. Essentially,
+ * thread A will take the lu_sites_guard lock and sleep on the ht_lock,
+ * while thread B will take the ht_lock and sleep on the lu_sites_guard
+ * lock. Obviously neither thread will wake and drop their respective hold
+ * on their lock.
+ *
+ * To prevent this from happening we must ensure the lu_sites_guard lock is
+ * not taken while down this code path. ZFS reliably does not set the
+ * __GFP_FS bit in its code paths, so this can be used to determine if it
+ * is safe to take the lu_sites_guard lock.
+ *
+ * Ideally we should accurately return the remaining number of cached
+ * objects without taking the  lu_sites_guard lock, but this is not
+ * possible in the current implementation.
+ */
 static int lu_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
 {
         lu_site_stats_t stats;
@@ -1758,12 +1824,26 @@ static int lu_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
         int remain = shrink_param(sc, nr_to_scan);
         CFS_LIST_HEAD(splice);
 
-        if (remain != 0) {
-                if (!(shrink_param(sc, gfp_mask) & __GFP_FS))
+       if (!(shrink_param(sc, gfp_mask) & __GFP_FS)) {
+               if (remain != 0)
                         return -1;
-                CDEBUG(D_INODE, "Shrink %d objects\n", remain);
+               else
+                       /* We must not take the lu_sites_guard lock when
+                        * __GFP_FS is *not* set because of the deadlock
+                        * possibility detailed above. Additionally,
+                        * since we cannot determine the number of
+                        * objects in the cache without taking this
+                        * lock, we're in a particularly tough spot. As
+                        * a result, we'll just lie and say our cache is
+                        * empty. This _should_ be ok, as we can't
+                        * reclaim objects when __GFP_FS is *not* set
+                        * anyways.
+                        */
+                       return 0;
         }
 
+       CDEBUG(D_INODE, "Shrink %d objects\n", remain);
+
         cfs_mutex_lock(&lu_sites_guard);
         cfs_list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
                 if (shrink_param(sc, nr_to_scan) != 0) {
@@ -2033,3 +2113,53 @@ void lu_kmem_fini(struct lu_kmem_descr *caches)
         }
 }
 EXPORT_SYMBOL(lu_kmem_fini);
+
+/**
+ * Temporary solution to be able to assign fid in ->do_create()
+ * till we have fully-functional OST fids
+ */
+void lu_object_assign_fid(const struct lu_env *env, struct lu_object *o,
+                         const struct lu_fid *fid)
+{
+       struct lu_site          *s = o->lo_dev->ld_site;
+       struct lu_fid           *old = &o->lo_header->loh_fid;
+       struct lu_site_bkt_data *bkt;
+       struct lu_object        *shadow;
+       cfs_waitlink_t           waiter;
+       cfs_hash_t              *hs;
+       cfs_hash_bd_t            bd;
+       __u64                    version = 0;
+
+       LASSERT(fid_is_zero(old));
+
+       hs = s->ls_obj_hash;
+       cfs_hash_bd_get_and_lock(hs, (void *)fid, &bd, 1);
+       shadow = htable_lookup(s, &bd, fid, &waiter, &version);
+       /* supposed to be unique */
+       LASSERT(shadow == NULL);
+       *old = *fid;
+       bkt = cfs_hash_bd_extra_get(hs, &bd);
+       cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
+       bkt->lsb_busy++;
+       cfs_hash_bd_unlock(hs, &bd, 1);
+}
+EXPORT_SYMBOL(lu_object_assign_fid);
+
+/**
+ * allocates object with 0 (non-assiged) fid
+ * XXX: temporary solution to be able to assign fid in ->do_create()
+ *      till we have fully-functional OST fids
+ */
+struct lu_object *lu_object_anon(const struct lu_env *env,
+                                struct lu_device *dev,
+                                const struct lu_object_conf *conf)
+{
+       struct lu_fid     fid;
+       struct lu_object *o;
+
+       fid_zero(&fid);
+       o = lu_object_alloc(env, dev, &fid, conf);
+
+       return o;
+}
+EXPORT_SYMBOL(lu_object_anon);