diff options
| -rw-r--r-- | fs/mount.h | 5 | ||||
| -rw-r--r-- | fs/namespace.c | 71 |
2 files changed, 57 insertions, 19 deletions
diff --git a/fs/mount.h b/fs/mount.h index 6740a6215529..8f2a14ae38a2 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -29,7 +29,10 @@ struct mount { struct mount *mnt_parent; struct dentry *mnt_mountpoint; struct vfsmount mnt; - struct rcu_head mnt_rcu; + union { + struct rcu_head mnt_rcu; + struct llist_node mnt_llist; + }; #ifdef CONFIG_SMP struct mnt_pcp __percpu *mnt_pcp; #else diff --git a/fs/namespace.c b/fs/namespace.c index ef42d9bee212..044134315f93 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -23,6 +23,7 @@ #include <linux/proc_ns.h> #include <linux/magic.h> #include <linux/bootmem.h> +#include <linux/task_work.h> #include "pnode.h" #include "internal.h" @@ -957,6 +958,46 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, return ERR_PTR(err); } +static void cleanup_mnt(struct mount *mnt) +{ + /* + * This probably indicates that somebody messed + * up a mnt_want/drop_write() pair. If this + * happens, the filesystem was probably unable + * to make r/w->r/o transitions. + */ + /* + * The locking used to deal with mnt_count decrement provides barriers, + * so mnt_get_writers() below is safe. + */ + WARN_ON(mnt_get_writers(mnt)); + if (unlikely(mnt->mnt_pins.first)) + mnt_pin_kill(mnt); + fsnotify_vfsmount_delete(&mnt->mnt); + dput(mnt->mnt.mnt_root); + deactivate_super(mnt->mnt.mnt_sb); + mnt_free_id(mnt); + call_rcu(&mnt->mnt_rcu, delayed_free_vfsmnt); +} + +static void __cleanup_mnt(struct rcu_head *head) +{ + cleanup_mnt(container_of(head, struct mount, mnt_rcu)); +} + +static LLIST_HEAD(delayed_mntput_list); +static void delayed_mntput(struct work_struct *unused) +{ + struct llist_node *node = llist_del_all(&delayed_mntput_list); + struct llist_node *next; + + for (; node; node = next) { + next = llist_next(node); + cleanup_mnt(llist_entry(node, struct mount, mnt_llist)); + } +} +static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput); + static void mntput_no_expire(struct mount *mnt) { rcu_read_lock(); @@ -982,24 +1023,18 @@ static void mntput_no_expire(struct mount *mnt) list_del(&mnt->mnt_instance); unlock_mount_hash(); - /* - * This probably indicates that somebody messed - * up a mnt_want/drop_write() pair. If this - * happens, the filesystem was probably unable - * to make r/w->r/o transitions. - */ - /* - * The locking used to deal with mnt_count decrement provides barriers, - * so mnt_get_writers() below is safe. - */ - WARN_ON(mnt_get_writers(mnt)); - if (unlikely(mnt->mnt_pins.first)) - mnt_pin_kill(mnt); - fsnotify_vfsmount_delete(&mnt->mnt); - dput(mnt->mnt.mnt_root); - deactivate_super(mnt->mnt.mnt_sb); - mnt_free_id(mnt); - call_rcu(&mnt->mnt_rcu, delayed_free_vfsmnt); + if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) { + struct task_struct *task = current; + if (likely(!(task->flags & PF_KTHREAD))) { + init_task_work(&mnt->mnt_rcu, __cleanup_mnt); + if (!task_work_add(task, &mnt->mnt_rcu, true)) + return; + } + if (llist_add(&mnt->mnt_llist, &delayed_mntput_list)) + schedule_delayed_work(&delayed_mntput_work, 1); + return; + } + cleanup_mnt(mnt); } void mntput(struct vfsmount *mnt) |