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Commit 18253e03 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull dcache and mountpoint updates from Al Viro:
 "Saner handling of refcounts to mountpoints.

  Transfer the counting reference from struct mount ->mnt_mountpoint
  over to struct mountpoint ->m_dentry. That allows us to get rid of the
  convoluted games with ordering of mount shutdowns.

  The cost is in teaching shrink_dcache_{parent,for_umount} to cope with
  mixed-filesystem shrink lists, which we'll also need for the Slab
  Movable Objects patchset"

* 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  switch the remnants of releasing the mountpoint away from fs_pin
  get rid of detach_mnt()
  make struct mountpoint bear the dentry reference to mountpoint, not struct mount
  Teach shrink_dcache_parent() to cope with mixed-filesystem shrink lists
  fs/namespace.c: shift put_mountpoint() to callers of unhash_mnt()
  __detach_mounts(): lookup_mountpoint() can't return ERR_PTR() anymore
  nfs: dget_parent() never returns NULL
  ceph: don't open-code the check for dead lockref
parents abdfd52a 56cbb429

fs/ceph/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -1267,7 +1267,7 @@ __dentry_leases_walk(struct ceph_mds_client *mdsc, 
		if (!spin_trylock(&dentry->d_lock))

			continue;



		if (dentry->d_lockref.count < 0) {

		if (__lockref_is_dead(&dentry->d_lockref)) {

			list_del_init(&di->lease_list);

			goto next;

		}

fs/dcache.c

+83 −17
Original line number Diff line number Diff line
@@ -861,6 +861,32 @@ void dput(struct dentry *dentry) 
}

EXPORT_SYMBOL(dput);



static void __dput_to_list(struct dentry *dentry, struct list_head *list)

__must_hold(&dentry->d_lock)

{

	if (dentry->d_flags & DCACHE_SHRINK_LIST) {

		/* let the owner of the list it's on deal with it */

		--dentry->d_lockref.count;

	} else {

		if (dentry->d_flags & DCACHE_LRU_LIST)

			d_lru_del(dentry);

		if (!--dentry->d_lockref.count)

			d_shrink_add(dentry, list);

	}

}



void dput_to_list(struct dentry *dentry, struct list_head *list)

{

	rcu_read_lock();

	if (likely(fast_dput(dentry))) {

		rcu_read_unlock();

		return;

	}

	rcu_read_unlock();

	if (!retain_dentry(dentry))

		__dput_to_list(dentry, list);

	spin_unlock(&dentry->d_lock);

}



/* This must be called with d_lock held */

static inline void __dget_dlock(struct dentry *dentry)
@@ -1067,7 +1093,7 @@ static bool shrink_lock_dentry(struct dentry *dentry) 
	return false;

}



static void shrink_dentry_list(struct list_head *list)

void shrink_dentry_list(struct list_head *list)

{

	while (!list_empty(list)) {

		struct dentry *dentry, *parent;
@@ -1089,18 +1115,9 @@ static void shrink_dentry_list(struct list_head *list) 
		rcu_read_unlock();

		d_shrink_del(dentry);

		parent = dentry->d_parent;

		if (parent != dentry)

			__dput_to_list(parent, list);

		__dentry_kill(dentry);

		if (parent == dentry)

			continue;

		/*

		 * We need to prune ancestors too. This is necessary to prevent

		 * quadratic behavior of shrink_dcache_parent(), but is also

		 * expected to be beneficial in reducing dentry cache

		 * fragmentation.

		 */

		dentry = parent;

		while (dentry && !lockref_put_or_lock(&dentry->d_lockref))

			dentry = dentry_kill(dentry);

	}

}
@@ -1445,8 +1462,11 @@ int d_set_mounted(struct dentry *dentry) 


struct select_data {

	struct dentry *start;

	union {

		long found;

		struct dentry *victim;

	};

	struct list_head dispose;

	int found;

};



static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
@@ -1478,6 +1498,37 @@ static enum d_walk_ret select_collect(void *_data, struct dentry *dentry) 
	return ret;

}



static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)

{

	struct select_data *data = _data;

	enum d_walk_ret ret = D_WALK_CONTINUE;



	if (data->start == dentry)

		goto out;



	if (dentry->d_flags & DCACHE_SHRINK_LIST) {

		if (!dentry->d_lockref.count) {

			rcu_read_lock();

			data->victim = dentry;

			return D_WALK_QUIT;

		}

	} else {

		if (dentry->d_flags & DCACHE_LRU_LIST)

			d_lru_del(dentry);

		if (!dentry->d_lockref.count)

			d_shrink_add(dentry, &data->dispose);

	}

	/*

	 * We can return to the caller if we have found some (this

	 * ensures forward progress). We'll be coming back to find

	 * the rest.

	 */

	if (!list_empty(&data->dispose))

		ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;

out:

	return ret;

}



/**

 * shrink_dcache_parent - prune dcache

 * @parent: parent of entries to prune
@@ -1487,12 +1538,9 @@ static enum d_walk_ret select_collect(void *_data, struct dentry *dentry) 
void shrink_dcache_parent(struct dentry *parent)

{

	for (;;) {

		struct select_data data;

		struct select_data data = {.start = parent};



		INIT_LIST_HEAD(&data.dispose);

		data.start = parent;

		data.found = 0;



		d_walk(parent, &data, select_collect);



		if (!list_empty(&data.dispose)) {
@@ -1503,6 +1551,24 @@ void shrink_dcache_parent(struct dentry *parent) 
		cond_resched();

		if (!data.found)

			break;

		data.victim = NULL;

		d_walk(parent, &data, select_collect2);

		if (data.victim) {

			struct dentry *parent;

			spin_lock(&data.victim->d_lock);

			if (!shrink_lock_dentry(data.victim)) {

				spin_unlock(&data.victim->d_lock);

				rcu_read_unlock();

			} else {

				rcu_read_unlock();

				parent = data.victim->d_parent;

				if (parent != data.victim)

					__dput_to_list(parent, &data.dispose);

				__dentry_kill(data.victim);

			}

		}

		if (!list_empty(&data.dispose))

			shrink_dentry_list(&data.dispose);

	}

}

EXPORT_SYMBOL(shrink_dcache_parent);

fs/fs_pin.c

+2 −8
Original line number Diff line number Diff line
@@ -19,20 +19,14 @@ void pin_remove(struct fs_pin *pin) 
	spin_unlock_irq(&pin->wait.lock);

}



void pin_insert_group(struct fs_pin *pin, struct vfsmount *m, struct hlist_head *p)

void pin_insert(struct fs_pin *pin, struct vfsmount *m)

{

	spin_lock(&pin_lock);

	if (p)

		hlist_add_head(&pin->s_list, p);

	hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);

	hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);

	spin_unlock(&pin_lock);

}



void pin_insert(struct fs_pin *pin, struct vfsmount *m)

{

	pin_insert_group(pin, m, &m->mnt_sb->s_pins);

}



void pin_kill(struct fs_pin *p)

{

	wait_queue_entry_t wait;

fs/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -157,6 +157,8 @@ extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc); 
extern struct dentry *d_alloc_cursor(struct dentry *);

extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);

extern char *simple_dname(struct dentry *, char *, int);

extern void dput_to_list(struct dentry *, struct list_head *);

extern void shrink_dentry_list(struct list_head *);



/*

 * read_write.c

fs/mount.h

+5 −3
Original line number Diff line number Diff line
@@ -58,7 +58,10 @@ struct mount { 
	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */

	struct mnt_namespace *mnt_ns;	/* containing namespace */

	struct mountpoint *mnt_mp;	/* where is it mounted */

	union {

		struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */

		struct hlist_node mnt_umount;

	};

	struct list_head mnt_umounting; /* list entry for umount propagation */

#ifdef CONFIG_FSNOTIFY

	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
@@ -68,8 +71,7 @@ struct mount { 
	int mnt_group_id;		/* peer group identifier */

	int mnt_expiry_mark;		/* true if marked for expiry */

	struct hlist_head mnt_pins;

	struct fs_pin mnt_umount;

	struct dentry *mnt_ex_mountpoint;

	struct hlist_head mnt_stuck_children;

} __randomize_layout;



#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */