[PATCH 01/28] staging/lustre/llite: allocate and free client cache asynchronously

Oleg Drokin
2016-06-20T03:04:46Z

From: Emoly Liu <emoly.liu@intel.com>

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>
---
drivers/staging/lustre/lustre/include/cl_object.h | 10 ++++-
drivers/staging/lustre/lustre/include/obd.h | 2 +-
.../staging/lustre/lustre/llite/llite_internal.h | 2 +-
drivers/staging/lustre/lustre/llite/llite_lib.c | 35 +++++++---------
drivers/staging/lustre/lustre/llite/lproc_llite.c | 6 +--
drivers/staging/lustre/lustre/lov/lov_obd.c | 7 ++++
drivers/staging/lustre/lustre/obdclass/cl_page.c | 46 ++++++++++++++++++++++
drivers/staging/lustre/lustre/osc/osc_page.c | 4 +-
drivers/staging/lustre/lustre/osc/osc_request.c | 4 +-
9 files changed, 86 insertions(+), 30 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/cl_object.h b/drivers/staging/lustre/lustre/include/cl_object.h
index 36ca935..3cd4a25 100644
--- 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 e654d42..ed1081a 100644
--- 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 7c1a3254..74cd241 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -493,7 +493,7 @@ 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 ac833db..83f4e1a 100644
--- 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);
}

@@ -514,8 +515,8 @@ 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) {
@@ -560,8 +561,6 @@ 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:
@@ -618,10 +617,6 @@ 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);

@@ -962,12 +957,12 @@ 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 6e9a8a5..1f00bce 100644
--- a/drivers/staging/lustre/lustre/llite/lproc_llite.c
+++ b/drivers/staging/lustre/lustre/llite/lproc_llite.c
@@ -360,7 +360,7 @@ 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;
@@ -387,7 +387,7 @@ 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;
@@ -826,7 +826,7 @@ 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 c87096e..9b92d55 100644
--- 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 71bff49..db2dc6b 100644
--- 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 57d8a5a..c1aa11e 100644
--- a/drivers/staging/lustre/lustre/osc/osc_page.c
+++ b/drivers/staging/lustre/lustre/osc/osc_page.c
@@ -414,7 +414,7 @@ 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.
@@ -714,7 +714,7 @@ 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 7260027..9334349 100644
--- 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;
}

--
2.7.4