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Commit 55f6e30d authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Revert "kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()" 



This reverts commit f601f9a2.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7653fe9d

fs/kernfs/dir.c

+9 −33
Original line number Diff line number Diff line
@@ -121,17 +121,13 @@ static int kernfs_link_sibling(struct kernfs_node *kn) 
 *	Locking:

 *	mutex_lock(kernfs_mutex)

 */

static bool kernfs_unlink_sibling(struct kernfs_node *kn)

static void kernfs_unlink_sibling(struct kernfs_node *kn)

{

	if (RB_EMPTY_NODE(&kn->rb))

		return false;



	if (kernfs_type(kn) == KERNFS_DIR)

		kn->parent->dir.subdirs--;



	rb_erase(&kn->rb, &kn->parent->dir.children);

	RB_CLEAR_NODE(&kn->rb);

	return true;

}



/**
@@ -500,6 +496,7 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt) 


		acxt->removed = kn->u.removed_list;



		kernfs_unmap_bin_file(kn);

		kernfs_put(kn);

	}

}
@@ -857,44 +854,23 @@ static void __kernfs_remove(struct kernfs_addrm_cxt *acxt, 


	/* unlink the subtree node-by-node */

	do {

		pos = kernfs_leftmost_descendant(kn);



		/*

		 * We're gonna release kernfs_mutex to unmap bin files,

		 * Make sure @pos doesn't go away inbetween.

		 */

		kernfs_get(pos);

		struct kernfs_iattrs *ps_iattr;



		/*

		 * This must be come before unlinking; otherwise, when

		 * there are multiple removers, some may finish before

		 * unmapping is complete.

		 */

		if (pos->flags & KERNFS_HAS_MMAP) {

			mutex_unlock(&kernfs_mutex);

			kernfs_unmap_file(pos);

			mutex_lock(&kernfs_mutex);

		}

		pos = kernfs_leftmost_descendant(kn);



		/*

		 * kernfs_unlink_sibling() succeeds once per node.  Use it

		 * to decide who's responsible for cleanups.

		 */

		if (!pos->parent || kernfs_unlink_sibling(pos)) {

			struct kernfs_iattrs *ps_iattr =

				pos->parent ? pos->parent->iattr : NULL;

		if (pos->parent) {

			kernfs_unlink_sibling(pos);



			/* update timestamps on the parent */

			ps_iattr = pos->parent->iattr;

			if (ps_iattr) {

				ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;

				ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;

			}

		}



		pos->u.removed_list = acxt->removed;

		acxt->removed = pos;

		}



		kernfs_put(pos);

	} while (pos != kn);

}

fs/kernfs/file.c

+4 −1
Original line number Diff line number Diff line
@@ -700,11 +700,14 @@ static int kernfs_fop_release(struct inode *inode, struct file *filp) 
	return 0;

}



void kernfs_unmap_file(struct kernfs_node *kn)

void kernfs_unmap_bin_file(struct kernfs_node *kn)

{

	struct kernfs_open_node *on;

	struct kernfs_open_file *of;



	if (!(kn->flags & KERNFS_HAS_MMAP))

		return;



	spin_lock_irq(&kernfs_open_node_lock);

	on = kn->attr.open;

	if (on)

fs/kernfs/kernfs-internal.h

+1 −1
Original line number Diff line number Diff line
@@ -113,7 +113,7 @@ struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name, 
 */

extern const struct file_operations kernfs_file_fops;



void kernfs_unmap_file(struct kernfs_node *kn);

void kernfs_unmap_bin_file(struct kernfs_node *kn);



/*

 * symlink.c