diff options
Diffstat (limited to 'fs/mbcache.c')
| -rw-r--r-- | fs/mbcache.c | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/fs/mbcache.c b/fs/mbcache.c index 187477ded6b3..de509271d031 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -222,8 +222,19 @@ __mb_cache_entry_release(struct mb_cache_entry *ce) * then reacquire the lock in the proper order. */ spin_lock(&mb_cache_spinlock); - if (list_empty(&ce->e_lru_list)) - list_add_tail(&ce->e_lru_list, &mb_cache_lru_list); + /* + * Evaluate the conditions under global lock mb_cache_spinlock, + * to check if mb_cache_entry_get() is running now + * and has already deleted the entry from mb_cache_lru_list + * and incremented ce->e_refcnt to prevent further additions + * to mb_cache_lru_list. + */ + if (!(ce->e_used || ce->e_queued || + atomic_read(&ce->e_refcnt))) { + if (list_empty(&ce->e_lru_list)) + list_add_tail(&ce->e_lru_list, + &mb_cache_lru_list); + } spin_unlock(&mb_cache_spinlock); } __spin_unlock_mb_cache_entry(ce); @@ -262,7 +273,6 @@ mb_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) list_del_init(&ce->e_lru_list); if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt)) continue; - spin_unlock(&mb_cache_spinlock); /* Prevent any find or get operation on the entry */ hlist_bl_lock(ce->e_block_hash_p); hlist_bl_lock(ce->e_index_hash_p); @@ -271,10 +281,10 @@ mb_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) !list_empty(&ce->e_lru_list)) { hlist_bl_unlock(ce->e_index_hash_p); hlist_bl_unlock(ce->e_block_hash_p); - spin_lock(&mb_cache_spinlock); continue; } __mb_cache_entry_unhash_unlock(ce); + spin_unlock(&mb_cache_spinlock); list_add_tail(&ce->e_lru_list, &free_list); spin_lock(&mb_cache_spinlock); } @@ -516,7 +526,6 @@ mb_cache_entry_alloc(struct mb_cache *cache, gfp_t gfp_flags) if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt)) continue; - spin_unlock(&mb_cache_spinlock); /* * Prevent any find or get operation on the * entry. @@ -530,13 +539,13 @@ mb_cache_entry_alloc(struct mb_cache *cache, gfp_t gfp_flags) hlist_bl_unlock(ce->e_index_hash_p); hlist_bl_unlock(ce->e_block_hash_p); l = &mb_cache_lru_list; - spin_lock(&mb_cache_spinlock); continue; } mb_assert(list_empty(&ce->e_lru_list)); mb_assert(!(ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt))); __mb_cache_entry_unhash_unlock(ce); + spin_unlock(&mb_cache_spinlock); goto found; } } @@ -670,6 +679,7 @@ mb_cache_entry_get(struct mb_cache *cache, struct block_device *bdev, cache->c_bucket_bits); block_hash_p = &cache->c_block_hash[bucket]; /* First serialize access to the block corresponding hash chain. */ + spin_lock(&mb_cache_spinlock); hlist_bl_lock(block_hash_p); hlist_bl_for_each_entry(ce, l, block_hash_p, e_block_list) { mb_assert(ce->e_block_hash_p == block_hash_p); @@ -678,9 +688,11 @@ mb_cache_entry_get(struct mb_cache *cache, struct block_device *bdev, * Prevent a free from removing the entry. */ atomic_inc(&ce->e_refcnt); + if (!list_empty(&ce->e_lru_list)) + list_del_init(&ce->e_lru_list); hlist_bl_unlock(block_hash_p); + spin_unlock(&mb_cache_spinlock); __spin_lock_mb_cache_entry(ce); - atomic_dec(&ce->e_refcnt); if (ce->e_used > 0) { DEFINE_WAIT(wait); while (ce->e_used > 0) { @@ -695,13 +707,9 @@ mb_cache_entry_get(struct mb_cache *cache, struct block_device *bdev, finish_wait(&mb_cache_queue, &wait); } ce->e_used += 1 + MB_CACHE_WRITER; + atomic_dec(&ce->e_refcnt); __spin_unlock_mb_cache_entry(ce); - if (!list_empty(&ce->e_lru_list)) { - spin_lock(&mb_cache_spinlock); - list_del_init(&ce->e_lru_list); - spin_unlock(&mb_cache_spinlock); - } if (!__mb_cache_entry_is_block_hashed(ce)) { __mb_cache_entry_release(ce); return NULL; @@ -710,6 +718,7 @@ mb_cache_entry_get(struct mb_cache *cache, struct block_device *bdev, } } hlist_bl_unlock(block_hash_p); + spin_unlock(&mb_cache_spinlock); return NULL; } |