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-rw-r--r--fs/super.c102
1 files changed, 62 insertions, 40 deletions
diff --git a/fs/super.c b/fs/super.c
index 2d762ce67f..076392396e 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -178,7 +178,7 @@ static void super_wake(struct super_block *sb, unsigned int flag)
* One thing we have to be careful of with a per-sb shrinker is that we don't
* drop the last active reference to the superblock from within the shrinker.
* If that happens we could trigger unregistering the shrinker from within the
- * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we
+ * shrinker path and that leads to deadlock on the shrinker_mutex. Hence we
* take a passive reference to the superblock to avoid this from occurring.
*/
static unsigned long super_cache_scan(struct shrinker *shrink,
@@ -191,7 +191,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
long dentries;
long inodes;
- sb = container_of(shrink, struct super_block, s_shrink);
+ sb = shrink->private_data;
/*
* Deadlock avoidance. We may hold various FS locks, and we don't want
@@ -244,7 +244,7 @@ static unsigned long super_cache_count(struct shrinker *shrink,
struct super_block *sb;
long total_objects = 0;
- sb = container_of(shrink, struct super_block, s_shrink);
+ sb = shrink->private_data;
/*
* We don't call super_trylock_shared() here as it is a scalability
@@ -306,7 +306,7 @@ static void destroy_unused_super(struct super_block *s)
security_sb_free(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
- free_prealloced_shrinker(&s->s_shrink);
+ shrinker_free(s->s_shrink);
/* no delays needed */
destroy_super_work(&s->destroy_work);
}
@@ -383,16 +383,19 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
s->s_time_min = TIME64_MIN;
s->s_time_max = TIME64_MAX;
- s->s_shrink.seeks = DEFAULT_SEEKS;
- s->s_shrink.scan_objects = super_cache_scan;
- s->s_shrink.count_objects = super_cache_count;
- s->s_shrink.batch = 1024;
- s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE;
- if (prealloc_shrinker(&s->s_shrink, "sb-%s", type->name))
+ s->s_shrink = shrinker_alloc(SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE,
+ "sb-%s", type->name);
+ if (!s->s_shrink)
goto fail;
- if (list_lru_init_memcg(&s->s_dentry_lru, &s->s_shrink))
+
+ s->s_shrink->scan_objects = super_cache_scan;
+ s->s_shrink->count_objects = super_cache_count;
+ s->s_shrink->batch = 1024;
+ s->s_shrink->private_data = s;
+
+ if (list_lru_init_memcg(&s->s_dentry_lru, s->s_shrink))
goto fail;
- if (list_lru_init_memcg(&s->s_inode_lru, &s->s_shrink))
+ if (list_lru_init_memcg(&s->s_inode_lru, s->s_shrink))
goto fail;
return s;
@@ -477,7 +480,7 @@ void deactivate_locked_super(struct super_block *s)
{
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
- unregister_shrinker(&s->s_shrink);
+ shrinker_free(s->s_shrink);
fs->kill_sb(s);
kill_super_notify(s);
@@ -818,7 +821,7 @@ retry:
hlist_add_head(&s->s_instances, &s->s_type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(s->s_type);
- register_shrinker_prepared(&s->s_shrink);
+ shrinker_register(s->s_shrink);
return s;
share_extant_sb:
@@ -901,7 +904,7 @@ retry:
hlist_add_head(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(type);
- register_shrinker_prepared(&s->s_shrink);
+ shrinker_register(s->s_shrink);
return s;
}
EXPORT_SYMBOL(sget);
@@ -1419,32 +1422,48 @@ EXPORT_SYMBOL(sget_dev);
#ifdef CONFIG_BLOCK
/*
- * Lock a super block that the callers holds a reference to.
+ * Lock the superblock that is holder of the bdev. Returns the superblock
+ * pointer if we successfully locked the superblock and it is alive. Otherwise
+ * we return NULL and just unlock bdev->bd_holder_lock.
*
- * The caller needs to ensure that the super_block isn't being freed while
- * calling this function, e.g. by holding a lock over the call to this function
- * and the place that clears the pointer to the superblock used by this function
- * before freeing the superblock.
+ * The function must be called with bdev->bd_holder_lock and releases it.
*/
-static bool super_lock_shared_active(struct super_block *sb)
+static struct super_block *bdev_super_lock_shared(struct block_device *bdev)
+ __releases(&bdev->bd_holder_lock)
{
- bool born = super_lock_shared(sb);
+ struct super_block *sb = bdev->bd_holder;
+ bool born;
+
+ lockdep_assert_held(&bdev->bd_holder_lock);
+ lockdep_assert_not_held(&sb->s_umount);
+ lockdep_assert_not_held(&bdev->bd_disk->open_mutex);
+ /* Make sure sb doesn't go away from under us */
+ spin_lock(&sb_lock);
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+ mutex_unlock(&bdev->bd_holder_lock);
+
+ born = super_lock_shared(sb);
if (!born || !sb->s_root || !(sb->s_flags & SB_ACTIVE)) {
super_unlock_shared(sb);
- return false;
+ put_super(sb);
+ return NULL;
}
- return true;
+ /*
+ * The superblock is active and we hold s_umount, we can drop our
+ * temporary reference now.
+ */
+ put_super(sb);
+ return sb;
}
static void fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
{
- struct super_block *sb = bdev->bd_holder;
-
- /* bd_holder_lock ensures that the sb isn't freed */
- lockdep_assert_held(&bdev->bd_holder_lock);
+ struct super_block *sb;
- if (!super_lock_shared_active(sb))
+ sb = bdev_super_lock_shared(bdev);
+ if (!sb)
return;
if (!surprise)
@@ -1459,11 +1478,10 @@ static void fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
static void fs_bdev_sync(struct block_device *bdev)
{
- struct super_block *sb = bdev->bd_holder;
-
- lockdep_assert_held(&bdev->bd_holder_lock);
+ struct super_block *sb;
- if (!super_lock_shared_active(sb))
+ sb = bdev_super_lock_shared(bdev);
+ if (!sb)
return;
sync_filesystem(sb);
super_unlock_shared(sb);
@@ -1479,14 +1497,16 @@ int setup_bdev_super(struct super_block *sb, int sb_flags,
struct fs_context *fc)
{
blk_mode_t mode = sb_open_mode(sb_flags);
+ struct bdev_handle *bdev_handle;
struct block_device *bdev;
- bdev = blkdev_get_by_dev(sb->s_dev, mode, sb, &fs_holder_ops);
- if (IS_ERR(bdev)) {
+ bdev_handle = bdev_open_by_dev(sb->s_dev, mode, sb, &fs_holder_ops);
+ if (IS_ERR(bdev_handle)) {
if (fc)
errorf(fc, "%s: Can't open blockdev", fc->source);
- return PTR_ERR(bdev);
+ return PTR_ERR(bdev_handle);
}
+ bdev = bdev_handle->bdev;
/*
* This really should be in blkdev_get_by_dev, but right now can't due
@@ -1494,7 +1514,7 @@ int setup_bdev_super(struct super_block *sb, int sb_flags,
* writable from userspace even for a read-only block device.
*/
if ((mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
- blkdev_put(bdev, sb);
+ bdev_release(bdev_handle);
return -EACCES;
}
@@ -1510,10 +1530,11 @@ int setup_bdev_super(struct super_block *sb, int sb_flags,
mutex_unlock(&bdev->bd_fsfreeze_mutex);
if (fc)
warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
- blkdev_put(bdev, sb);
+ bdev_release(bdev_handle);
return -EBUSY;
}
spin_lock(&sb_lock);
+ sb->s_bdev_handle = bdev_handle;
sb->s_bdev = bdev;
sb->s_bdi = bdi_get(bdev->bd_disk->bdi);
if (bdev_stable_writes(bdev))
@@ -1522,7 +1543,7 @@ int setup_bdev_super(struct super_block *sb, int sb_flags,
mutex_unlock(&bdev->bd_fsfreeze_mutex);
snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
- shrinker_debugfs_rename(&sb->s_shrink, "sb-%s:%s", sb->s_type->name,
+ shrinker_debugfs_rename(sb->s_shrink, "sb-%s:%s", sb->s_type->name,
sb->s_id);
sb_set_blocksize(sb, block_size(bdev));
return 0;
@@ -1646,7 +1667,7 @@ void kill_block_super(struct super_block *sb)
generic_shutdown_super(sb);
if (bdev) {
sync_blockdev(bdev);
- blkdev_put(bdev, sb);
+ bdev_release(sb->s_bdev_handle);
}
}
@@ -2139,3 +2160,4 @@ int sb_init_dio_done_wq(struct super_block *sb)
destroy_workqueue(wq);
return 0;
}
+EXPORT_SYMBOL_GPL(sb_init_dio_done_wq);