staging/lustre/llite: allocate and free client cache asynchronously

Since the inflight request holds import refcount as well as export,
sometimes obd_disconnect() in client_common_put_super() can't put
the last refcount of OSC import (e.g. due to network disconnection),
this will cause cl_cache being accessed after free.

To fix this issue, ccc_users is used as cl_cache refcount, and
lov/llite/osc all hold one cl_cache refcount respectively, to avoid
the race that a new OST is being added into the system when the client
is mounted.
The following cl_cache functions are added:
- cl_cache_init(): allocate and initialize cl_cache
- cl_cache_incref(): increase cl_cache refcount
- cl_cache_decref(): decrease cl_cache refcount and free the cache
  if refcount=0.

Signed-off-by: Emoly Liu <emoly.liu@intel.com>
Reviewed-on: http://review.whamcloud.com/13746
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6173
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/include/cl_object.h b/drivers/staging/lustre/lustre/include/cl_object.h
index 36ca93548e805b1e45728388042647f49de21ee8..3cd4a2577d90d410801fe78c04bdda17bc59ec99 100644 (file)
--- a/drivers/staging/lustre/lustre/include/cl_object.h
+++ b/drivers/staging/lustre/lustre/include/cl_object.h
@@ -2322,7 +2322,8 @@ void cl_lock_descr_print(const struct lu_env *env, void *cookie,
  */
 struct cl_client_cache {
        /**
-        * # of users (OSCs)
+        * # of client cache refcount
+        * # of users (OSCs) + 2 (held by llite and lov)
         */
        atomic_t                ccc_users;
        /**
@@ -2357,6 +2358,13 @@ struct cl_client_cache {
 
 };
 
+/**
+ * cl_cache functions
+ */
+struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
+void cl_cache_incref(struct cl_client_cache *cache);
+void cl_cache_decref(struct cl_client_cache *cache);
+
 /** @} cl_page */
 
 /** \defgroup cl_lock cl_lock

diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h
index 9971ee5023052592be811451c0b477989a17addb..40909b092c3642e7cb8fa0afeb1ea4960343f1dd 100644 (file)
--- a/drivers/staging/lustre/lustre/include/obd.h
+++ b/drivers/staging/lustre/lustre/include/obd.h
@@ -415,7 +415,7 @@ struct lov_obd {
        enum lustre_sec_part    lov_sp_me;
 
        /* Cached LRU and unstable data from upper layer */
-       void                   *lov_cache;
+       struct cl_client_cache *lov_cache;
 
        struct rw_semaphore     lov_notify_lock;
 

diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index 8fe63bd8ec009df13d4eec0f63f3d5e00199e515..657ebd0a2654cb20a8f8d28d27084cd405f759c3 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -452,7 +452,7 @@ struct ll_sb_info {
         * any page which is sent to a server as part of a bulk request,
         * but is uncommitted to stable storage.
         */
-       struct cl_client_cache    ll_cache;
+       struct cl_client_cache    *ll_cache;
 
        struct lprocfs_stats     *ll_ra_stats;
 

diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index ae6a571162fbaa363eb583ac077d9128595ed1d0..4ab1f2bb6181ae3514cc02759c94eaff5cfedd50 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -83,15 +83,11 @@ static struct ll_sb_info *ll_init_sbi(struct super_block *sb)
        pages = si.totalram - si.totalhigh;
        lru_page_max = pages / 2;
 
-       /* initialize ll_cache data */
-       atomic_set(&sbi->ll_cache.ccc_users, 0);
-       sbi->ll_cache.ccc_lru_max = lru_page_max;
-       atomic_set(&sbi->ll_cache.ccc_lru_left, lru_page_max);
-       spin_lock_init(&sbi->ll_cache.ccc_lru_lock);
-       INIT_LIST_HEAD(&sbi->ll_cache.ccc_lru);
-
-       atomic_set(&sbi->ll_cache.ccc_unstable_nr, 0);
-       init_waitqueue_head(&sbi->ll_cache.ccc_unstable_waitq);
+       sbi->ll_cache = cl_cache_init(lru_page_max);
+       if (!sbi->ll_cache) {
+               kfree(sbi);
+               return NULL;
+       }
 
        sbi->ll_ra_info.ra_max_pages_per_file = min(pages / 32,
                                           SBI_DEFAULT_READAHEAD_MAX);
@@ -131,6 +127,11 @@ static void ll_free_sbi(struct super_block *sb)
 {
        struct ll_sb_info *sbi = ll_s2sbi(sb);
 
+       if (sbi->ll_cache) {
+               cl_cache_decref(sbi->ll_cache);
+               sbi->ll_cache = NULL;
+       }
+
        kfree(sbi);
 }
 
@@ -488,8 +489,8 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
        cl_sb_init(sb);
 
        err = obd_set_info_async(NULL, sbi->ll_dt_exp, sizeof(KEY_CACHE_SET),
-                                KEY_CACHE_SET, sizeof(sbi->ll_cache),
-                                &sbi->ll_cache, NULL);
+                                KEY_CACHE_SET, sizeof(*sbi->ll_cache),
+                                sbi->ll_cache, NULL);
 
        sb->s_root = d_make_root(root);
        if (!sb->s_root) {
@@ -534,8 +535,6 @@ out_lock_cn_cb:
 out_dt:
        obd_disconnect(sbi->ll_dt_exp);
        sbi->ll_dt_exp = NULL;
-       /* Make sure all OScs are gone, since cl_cache is accessing sbi. */
-       obd_zombie_barrier();
 out_md_fid:
        obd_fid_fini(sbi->ll_md_exp->exp_obd);
 out_md:
@@ -585,10 +584,6 @@ static void client_common_put_super(struct super_block *sb)
        obd_fid_fini(sbi->ll_dt_exp->exp_obd);
        obd_disconnect(sbi->ll_dt_exp);
        sbi->ll_dt_exp = NULL;
-       /* wait till all OSCs are gone, since cl_cache is accessing sbi.
-        * see LU-2543.
-        */
-       obd_zombie_barrier();
 
        ldebugfs_unregister_mountpoint(sbi);
 
@@ -921,12 +916,12 @@ void ll_put_super(struct super_block *sb)
        if (!force) {
                struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
 
-               rc = l_wait_event(sbi->ll_cache.ccc_unstable_waitq,
-                                 !atomic_read(&sbi->ll_cache.ccc_unstable_nr),
+               rc = l_wait_event(sbi->ll_cache->ccc_unstable_waitq,
+                                 !atomic_read(&sbi->ll_cache->ccc_unstable_nr),
                                  &lwi);
        }
 
-       ccc_count = atomic_read(&sbi->ll_cache.ccc_unstable_nr);
+       ccc_count = atomic_read(&sbi->ll_cache->ccc_unstable_nr);
        if (!force && rc != -EINTR)
                LASSERTF(!ccc_count, "count: %i\n", ccc_count);
 

diff --git a/drivers/staging/lustre/lustre/llite/lproc_llite.c b/drivers/staging/lustre/lustre/llite/lproc_llite.c
index 18a777529d7b33331e22b70daa304382ee8aa2a9..e86bf3c53be3722e076a67c9314994902e280456 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/lproc_llite.c
+++ b/drivers/staging/lustre/lustre/llite/lproc_llite.c
@@ -356,7 +356,7 @@ static int ll_max_cached_mb_seq_show(struct seq_file *m, void *v)
 {
        struct super_block     *sb    = m->private;
        struct ll_sb_info      *sbi   = ll_s2sbi(sb);
-       struct cl_client_cache *cache = &sbi->ll_cache;
+       struct cl_client_cache *cache = sbi->ll_cache;
        int shift = 20 - PAGE_SHIFT;
        int max_cached_mb;
        int unused_mb;
@@ -383,7 +383,7 @@ static ssize_t ll_max_cached_mb_seq_write(struct file *file,
 {
        struct super_block *sb = ((struct seq_file *)file->private_data)->private;
        struct ll_sb_info *sbi = ll_s2sbi(sb);
-       struct cl_client_cache *cache = &sbi->ll_cache;
+       struct cl_client_cache *cache = sbi->ll_cache;
        struct lu_env *env;
        int refcheck;
        int mult, rc, pages_number;
@@ -822,7 +822,7 @@ static ssize_t unstable_stats_show(struct kobject *kobj,
 {
        struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
                                              ll_kobj);
-       struct cl_client_cache *cache = &sbi->ll_cache;
+       struct cl_client_cache *cache = sbi->ll_cache;
        int pages, mb;
 
        pages = atomic_read(&cache->ccc_unstable_nr);

diff --git a/drivers/staging/lustre/lustre/lov/lov_obd.c b/drivers/staging/lustre/lustre/lov/lov_obd.c
index c87096ee8d3882478e672e1add13bfcb31b2a36c..9b92d5522edb6b5e32af0e8b91810942f309f840 100644 (file)
--- a/drivers/staging/lustre/lustre/lov/lov_obd.c
+++ b/drivers/staging/lustre/lustre/lov/lov_obd.c
@@ -892,6 +892,12 @@ static int lov_cleanup(struct obd_device *obd)
                kfree(lov->lov_tgts);
                lov->lov_tgt_size = 0;
        }
+
+       if (lov->lov_cache) {
+               cl_cache_decref(lov->lov_cache);
+               lov->lov_cache = NULL;
+       }
+
        return 0;
 }
 
@@ -2121,6 +2127,7 @@ static int lov_set_info_async(const struct lu_env *env, struct obd_export *exp,
                LASSERT(!lov->lov_cache);
                lov->lov_cache = val;
                do_inactive = 1;
+               cl_cache_incref(lov->lov_cache);
        }
 
        for (i = 0; i < count; i++, val = (char *)val + incr) {

diff --git a/drivers/staging/lustre/lustre/obdclass/cl_page.c b/drivers/staging/lustre/lustre/obdclass/cl_page.c
index 71bff493cfc7c3da4e3a285e710f16e2ae7111a8..db2dc6b390736ef3c494273d6ed07c06d340d947 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/cl_page.c
+++ b/drivers/staging/lustre/lustre/obdclass/cl_page.c
@@ -1072,3 +1072,49 @@ void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
        slice->cpl_page = page;
 }
 EXPORT_SYMBOL(cl_page_slice_add);
+
+/**
+ * Allocate and initialize cl_cache, called by ll_init_sbi().
+ */
+struct cl_client_cache *cl_cache_init(unsigned long lru_page_max)
+{
+       struct cl_client_cache  *cache = NULL;
+
+       cache = kzalloc(sizeof(*cache), GFP_KERNEL);
+       if (!cache)
+               return NULL;
+
+       /* Initialize cache data */
+       atomic_set(&cache->ccc_users, 1);
+       cache->ccc_lru_max = lru_page_max;
+       atomic_set(&cache->ccc_lru_left, lru_page_max);
+       spin_lock_init(&cache->ccc_lru_lock);
+       INIT_LIST_HEAD(&cache->ccc_lru);
+
+       atomic_set(&cache->ccc_unstable_nr, 0);
+       init_waitqueue_head(&cache->ccc_unstable_waitq);
+
+       return cache;
+}
+EXPORT_SYMBOL(cl_cache_init);
+
+/**
+ * Increase cl_cache refcount
+ */
+void cl_cache_incref(struct cl_client_cache *cache)
+{
+       atomic_inc(&cache->ccc_users);
+}
+EXPORT_SYMBOL(cl_cache_incref);
+
+/**
+ * Decrease cl_cache refcount and free the cache if refcount=0.
+ * Since llite, lov and osc all hold cl_cache refcount,
+ * the free will not cause race. (LU-6173)
+ */
+void cl_cache_decref(struct cl_client_cache *cache)
+{
+       if (atomic_dec_and_test(&cache->ccc_users))
+               kfree(cache);
+}
+EXPORT_SYMBOL(cl_cache_decref);

diff --git a/drivers/staging/lustre/lustre/osc/osc_page.c b/drivers/staging/lustre/lustre/osc/osc_page.c
index 18c261b7f3b12d8b79eaad76db1ed51d3cf2c732..355f496a2093a5b957c12147ca2bd7695ec1dd4b 100644 (file)
--- a/drivers/staging/lustre/lustre/osc/osc_page.c
+++ b/drivers/staging/lustre/lustre/osc/osc_page.c
@@ -412,7 +412,7 @@ static int osc_cache_too_much(struct client_obd *cli)
        int pages = atomic_read(&cli->cl_lru_in_list);
        unsigned long budget;
 
-       budget = cache->ccc_lru_max / atomic_read(&cache->ccc_users);
+       budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2);
 
        /* if it's going to run out LRU slots, we should free some, but not
         * too much to maintain fairness among OSCs.
@@ -712,7 +712,7 @@ int osc_lru_reclaim(struct client_obd *cli)
        cache->ccc_lru_shrinkers++;
        list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
 
-       max_scans = atomic_read(&cache->ccc_users);
+       max_scans = atomic_read(&cache->ccc_users) - 2;
        while (--max_scans > 0 && !list_empty(&cache->ccc_lru)) {
                cli = list_entry(cache->ccc_lru.next, struct client_obd,
                                 cl_lru_osc);

diff --git a/drivers/staging/lustre/lustre/osc/osc_request.c b/drivers/staging/lustre/lustre/osc/osc_request.c
index 7260027bb59515c19a25e1d6aac9411f3df9a861..933434946d5be88093518d387bf3a2d1efcdf527 100644 (file)
--- a/drivers/staging/lustre/lustre/osc/osc_request.c
+++ b/drivers/staging/lustre/lustre/osc/osc_request.c
@@ -2913,7 +2913,7 @@ static int osc_set_info_async(const struct lu_env *env, struct obd_export *exp,
 
                LASSERT(!cli->cl_cache); /* only once */
                cli->cl_cache = val;
-               atomic_inc(&cli->cl_cache->ccc_users);
+               cl_cache_incref(cli->cl_cache);
                cli->cl_lru_left = &cli->cl_cache->ccc_lru_left;
 
                /* add this osc into entity list */
@@ -3293,7 +3293,7 @@ static int osc_cleanup(struct obd_device *obd)
                list_del_init(&cli->cl_lru_osc);
                spin_unlock(&cli->cl_cache->ccc_lru_lock);
                cli->cl_lru_left = NULL;
-               atomic_dec(&cli->cl_cache->ccc_users);
+               cl_cache_decref(cli->cl_cache);
                cli->cl_cache = NULL;
        }