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-rw-r--r--fs/super.c46
1 files changed, 21 insertions, 25 deletions
diff --git a/fs/super.c b/fs/super.c
index 994db21f59bf..d4e33e8f1e6f 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -155,21 +155,19 @@ static void destroy_super_rcu(struct rcu_head *head)
schedule_work(&s->destroy_work);
}
-/**
- * destroy_super - frees a superblock
- * @s: superblock to free
- *
- * Frees a superblock.
- */
-static void destroy_super(struct super_block *s)
+/* Free a superblock that has never been seen by anyone */
+static void destroy_unused_super(struct super_block *s)
{
+ if (!s)
+ return;
+ up_write(&s->s_umount);
list_lru_destroy(&s->s_dentry_lru);
list_lru_destroy(&s->s_inode_lru);
security_sb_free(s);
- WARN_ON(!list_empty(&s->s_mounts));
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
- call_rcu(&s->rcu, destroy_super_rcu);
+ /* no delays needed */
+ destroy_super_work(&s->destroy_work);
}
/**
@@ -257,7 +255,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
return s;
fail:
- destroy_super(s);
+ destroy_unused_super(s);
return NULL;
}
@@ -266,11 +264,17 @@ fail:
/*
* Drop a superblock's refcount. The caller must hold sb_lock.
*/
-static void __put_super(struct super_block *sb)
+static void __put_super(struct super_block *s)
{
- if (!--sb->s_count) {
- list_del_init(&sb->s_list);
- destroy_super(sb);
+ if (!--s->s_count) {
+ list_del_init(&s->s_list);
+ WARN_ON(s->s_dentry_lru.node);
+ WARN_ON(s->s_inode_lru.node);
+ WARN_ON(!list_empty(&s->s_mounts));
+ security_sb_free(s);
+ put_user_ns(s->s_user_ns);
+ kfree(s->s_subtype);
+ call_rcu(&s->rcu, destroy_super_rcu);
}
}
@@ -485,19 +489,12 @@ retry:
continue;
if (user_ns != old->s_user_ns) {
spin_unlock(&sb_lock);
- if (s) {
- up_write(&s->s_umount);
- destroy_super(s);
- }
+ destroy_unused_super(s);
return ERR_PTR(-EBUSY);
}
if (!grab_super(old))
goto retry;
- if (s) {
- up_write(&s->s_umount);
- destroy_super(s);
- s = NULL;
- }
+ destroy_unused_super(s);
return old;
}
}
@@ -512,8 +509,7 @@ retry:
err = set(s, data);
if (err) {
spin_unlock(&sb_lock);
- up_write(&s->s_umount);
- destroy_super(s);
+ destroy_unused_super(s);
return ERR_PTR(err);
}
s->s_type = type;