Commit af8be4e4 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  [PATCH] mnt_expire is protected by namespace_sem, no need for vfsmount_lock
  [PATCH] do shrink_submounts() for all fs types
  [PATCH] sanitize locking in mark_mounts_for_expiry() and shrink_submounts()
  [PATCH] count ghost references to vfsmounts
  [PATCH] reduce stack footprint in namespace.c
parents d478376c 6758f953

fs/afs/internal.h

+0 −1
Original line number Diff line number Diff line
@@ -573,7 +573,6 @@ extern const struct file_operations afs_mntpt_file_operations; 


extern int afs_mntpt_check_symlink(struct afs_vnode *, struct key *);

extern void afs_mntpt_kill_timer(void);

extern void afs_umount_begin(struct vfsmount *, int);



/*

 * proc.c

fs/afs/mntpt.c

+0 −8
Original line number Diff line number Diff line
@@ -283,11 +283,3 @@ void afs_mntpt_kill_timer(void) 
	cancel_delayed_work(&afs_mntpt_expiry_timer);

	flush_scheduled_work();

}
 


/*

 * begin unmount by attempting to remove all automounted mountpoints we added

 */

void afs_umount_begin(struct vfsmount *vfsmnt, int flags)

{

	shrink_submounts(vfsmnt, &afs_vfsmounts);

}

fs/afs/super.c

+0 −1
Original line number Diff line number Diff line
@@ -50,7 +50,6 @@ static const struct super_operations afs_super_ops = { 
	.write_inode	= afs_write_inode,

	.destroy_inode	= afs_destroy_inode,

	.clear_inode	= afs_clear_inode,

	.umount_begin	= afs_umount_begin,

	.put_super	= afs_put_super,

	.show_options	= generic_show_options,

};

fs/cifs/cifs_dfs_ref.c

+0 −1
Original line number Diff line number Diff line
@@ -33,7 +33,6 @@ void dfs_shrink_umount_helper(struct vfsmount *vfsmnt) 
{

	mark_mounts_for_expiry(&cifs_dfs_automount_list);

	mark_mounts_for_expiry(&cifs_dfs_automount_list);

	shrink_submounts(vfsmnt, &cifs_dfs_automount_list);

}



/**

fs/namespace.c

+69 −131
Original line number Diff line number Diff line
@@ -155,15 +155,15 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns) 
	}

}



static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)

static void detach_mnt(struct vfsmount *mnt, struct path *old_path)

{

	old_nd->path.dentry = mnt->mnt_mountpoint;

	old_nd->path.mnt = mnt->mnt_parent;

	old_path->dentry = mnt->mnt_mountpoint;

	old_path->mnt = mnt->mnt_parent;

	mnt->mnt_parent = mnt;

	mnt->mnt_mountpoint = mnt->mnt_root;

	list_del_init(&mnt->mnt_child);

	list_del_init(&mnt->mnt_hash);

	old_nd->path.dentry->d_mounted--;

	old_path->dentry->d_mounted--;

}



void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
@@ -174,12 +174,12 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, 
	dentry->d_mounted++;

}



static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)

static void attach_mnt(struct vfsmount *mnt, struct path *path)

{

	mnt_set_mountpoint(nd->path.mnt, nd->path.dentry, mnt);

	mnt_set_mountpoint(path->mnt, path->dentry, mnt);

	list_add_tail(&mnt->mnt_hash, mount_hashtable +

			hash(nd->path.mnt, nd->path.dentry));

	list_add_tail(&mnt->mnt_child, &nd->path.mnt->mnt_mounts);

			hash(path->mnt, path->dentry));

	list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);

}



/*
@@ -262,10 +262,8 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, 
		/* stick the duplicate mount on the same expiry list

		 * as the original if that was on one */

		if (flag & CL_EXPIRE) {

			spin_lock(&vfsmount_lock);

			if (!list_empty(&old->mnt_expire))

				list_add(&mnt->mnt_expire, &old->mnt_expire);

			spin_unlock(&vfsmount_lock);

		}

	}

	return mnt;
@@ -548,6 +546,7 @@ void release_mounts(struct list_head *head) 
			m = mnt->mnt_parent;

			mnt->mnt_mountpoint = mnt->mnt_root;

			mnt->mnt_parent = mnt;

			m->mnt_ghosts--;

			spin_unlock(&vfsmount_lock);

			dput(dentry);

			mntput(m);
@@ -572,12 +571,16 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) 
		__touch_mnt_namespace(p->mnt_ns);

		p->mnt_ns = NULL;

		list_del_init(&p->mnt_child);

		if (p->mnt_parent != p)

		if (p->mnt_parent != p) {

			p->mnt_parent->mnt_ghosts++;

			p->mnt_mountpoint->d_mounted--;

		}

		change_mnt_propagation(p, MS_PRIVATE);

	}

}



static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts);



static int do_umount(struct vfsmount *mnt, int flags)

{

	struct super_block *sb = mnt->mnt_sb;
@@ -650,6 +653,9 @@ static int do_umount(struct vfsmount *mnt, int flags) 
	spin_lock(&vfsmount_lock);

	event++;



	if (!(flags & MNT_DETACH))

		shrink_submounts(mnt, &umount_list);



	retval = -EBUSY;

	if (flags & MNT_DETACH || !propagate_mount_busy(mnt, 2)) {

		if (!list_empty(&mnt->mnt_list))
@@ -744,7 +750,7 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, 
					int flag)

{

	struct vfsmount *res, *p, *q, *r, *s;

	struct nameidata nd;

	struct path path;



	if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))

		return NULL;
@@ -769,14 +775,14 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, 
				q = q->mnt_parent;

			}

			p = s;

			nd.path.mnt = q;

			nd.path.dentry = p->mnt_mountpoint;

			path.mnt = q;

			path.dentry = p->mnt_mountpoint;

			q = clone_mnt(p, p->mnt_root, flag);

			if (!q)

				goto Enomem;

			spin_lock(&vfsmount_lock);

			list_add_tail(&q->mnt_list, &res->mnt_list);

			attach_mnt(q, &nd);

			attach_mnt(q, &path);

			spin_unlock(&vfsmount_lock);

		}

	}
@@ -876,11 +882,11 @@ void drop_collected_mounts(struct vfsmount *mnt) 
 * in allocations.

 */

static int attach_recursive_mnt(struct vfsmount *source_mnt,

			struct nameidata *nd, struct nameidata *parent_nd)

			struct path *path, struct path *parent_path)

{

	LIST_HEAD(tree_list);

	struct vfsmount *dest_mnt = nd->path.mnt;

	struct dentry *dest_dentry = nd->path.dentry;

	struct vfsmount *dest_mnt = path->mnt;

	struct dentry *dest_dentry = path->dentry;

	struct vfsmount *child, *p;



	if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
@@ -892,9 +898,9 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt, 
	}



	spin_lock(&vfsmount_lock);

	if (parent_nd) {

		detach_mnt(source_mnt, parent_nd);

		attach_mnt(source_mnt, nd);

	if (parent_path) {

		detach_mnt(source_mnt, parent_path);

		attach_mnt(source_mnt, path);

		touch_mnt_namespace(current->nsproxy->mnt_ns);

	} else {

		mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
@@ -930,7 +936,7 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) 


	err = -ENOENT;

	if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))

		err = attach_recursive_mnt(mnt, nd, NULL);

		err = attach_recursive_mnt(mnt, &nd->path, NULL);

out_unlock:

	mutex_unlock(&nd->path.dentry->d_inode->i_mutex);

	if (!err)
@@ -1059,7 +1065,8 @@ static inline int tree_contains_unbindable(struct vfsmount *mnt) 
 */

static noinline int do_move_mount(struct nameidata *nd, char *old_name)

{

	struct nameidata old_nd, parent_nd;

	struct nameidata old_nd;

	struct path parent_path;

	struct vfsmount *p;

	int err = 0;

	if (!capable(CAP_SYS_ADMIN))
@@ -1114,21 +1121,19 @@ static noinline int do_move_mount(struct nameidata *nd, char *old_name) 
		if (p == old_nd.path.mnt)

			goto out1;



	err = attach_recursive_mnt(old_nd.path.mnt, nd, &parent_nd);

	err = attach_recursive_mnt(old_nd.path.mnt, &nd->path, &parent_path);

	if (err)

		goto out1;



	spin_lock(&vfsmount_lock);

	/* if the mount is moved, it should no longer be expire

	 * automatically */

	list_del_init(&old_nd.path.mnt->mnt_expire);

	spin_unlock(&vfsmount_lock);

out1:

	mutex_unlock(&nd->path.dentry->d_inode->i_mutex);

out:

	up_write(&namespace_sem);

	if (!err)

		path_put(&parent_nd.path);

		path_put(&parent_path);

	path_put(&old_nd.path);

	return err;

}
@@ -1189,12 +1194,9 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, 
	if ((err = graft_tree(newmnt, nd)))

		goto unlock;



	if (fslist) {

		/* add to the specified expiration list */

		spin_lock(&vfsmount_lock);

	if (fslist) /* add to the specified expiration list */

		list_add_tail(&newmnt->mnt_expire, fslist);

		spin_unlock(&vfsmount_lock);

	}



	up_write(&namespace_sem);

	return 0;
@@ -1206,75 +1208,6 @@ unlock: 


EXPORT_SYMBOL_GPL(do_add_mount);



static void expire_mount(struct vfsmount *mnt, struct list_head *mounts,

				struct list_head *umounts)

{

	spin_lock(&vfsmount_lock);



	/*

	 * Check if mount is still attached, if not, let whoever holds it deal

	 * with the sucker

	 */

	if (mnt->mnt_parent == mnt) {

		spin_unlock(&vfsmount_lock);

		return;

	}



	/*

	 * Check that it is still dead: the count should now be 2 - as

	 * contributed by the vfsmount parent and the mntget above

	 */

	if (!propagate_mount_busy(mnt, 2)) {

		/* delete from the namespace */

		touch_mnt_namespace(mnt->mnt_ns);

		list_del_init(&mnt->mnt_list);

		mnt->mnt_ns = NULL;

		umount_tree(mnt, 1, umounts);

		spin_unlock(&vfsmount_lock);

	} else {

		/*

		 * Someone brought it back to life whilst we didn't have any

		 * locks held so return it to the expiration list

		 */

		list_add_tail(&mnt->mnt_expire, mounts);

		spin_unlock(&vfsmount_lock);

	}

}



/*

 * go through the vfsmounts we've just consigned to the graveyard to

 * - check that they're still dead

 * - delete the vfsmount from the appropriate namespace under lock

 * - dispose of the corpse

 */

static void expire_mount_list(struct list_head *graveyard, struct list_head *mounts)

{

	struct mnt_namespace *ns;

	struct vfsmount *mnt;



	while (!list_empty(graveyard)) {

		LIST_HEAD(umounts);

		mnt = list_first_entry(graveyard, struct vfsmount, mnt_expire);

		list_del_init(&mnt->mnt_expire);



		/* don't do anything if the namespace is dead - all the

		 * vfsmounts from it are going away anyway */

		ns = mnt->mnt_ns;

		if (!ns || !ns->root)

			continue;

		get_mnt_ns(ns);



		spin_unlock(&vfsmount_lock);

		down_write(&namespace_sem);

		expire_mount(mnt, mounts, &umounts);

		up_write(&namespace_sem);

		release_mounts(&umounts);

		mntput(mnt);

		put_mnt_ns(ns);

		spin_lock(&vfsmount_lock);

	}

}



/*

 * process a list of expirable mountpoints with the intent of discarding any

 * mountpoints that aren't in use and haven't been touched since last we came
@@ -1284,10 +1217,12 @@ void mark_mounts_for_expiry(struct list_head *mounts) 
{

	struct vfsmount *mnt, *next;

	LIST_HEAD(graveyard);

	LIST_HEAD(umounts);



	if (list_empty(mounts))

		return;



	down_write(&namespace_sem);

	spin_lock(&vfsmount_lock);



	/* extract from the expiration list every vfsmount that matches the
@@ -1298,16 +1233,19 @@ void mark_mounts_for_expiry(struct list_head *mounts) 
	 */

	list_for_each_entry_safe(mnt, next, mounts, mnt_expire) {

		if (!xchg(&mnt->mnt_expiry_mark, 1) ||

		    atomic_read(&mnt->mnt_count) != 1)

			propagate_mount_busy(mnt, 1))

			continue;



		mntget(mnt);

		list_move(&mnt->mnt_expire, &graveyard);

	}



	expire_mount_list(&graveyard, mounts);



	while (!list_empty(&graveyard)) {

		mnt = list_first_entry(&graveyard, struct vfsmount, mnt_expire);

		touch_mnt_namespace(mnt->mnt_ns);

		umount_tree(mnt, 1, &umounts);

	}

	spin_unlock(&vfsmount_lock);

	up_write(&namespace_sem);



	release_mounts(&umounts);

}



EXPORT_SYMBOL_GPL(mark_mounts_for_expiry);
@@ -1343,7 +1281,6 @@ resume: 
		}



		if (!propagate_mount_busy(mnt, 1)) {

			mntget(mnt);

			list_move_tail(&mnt->mnt_expire, graveyard);

			found++;

		}
@@ -1363,21 +1300,21 @@ resume: 
 * process a list of expirable mountpoints with the intent of discarding any

 * submounts of a specific parent mountpoint

 */

void shrink_submounts(struct vfsmount *mountpoint, struct list_head *mounts)

static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts)

{

	LIST_HEAD(graveyard);

	int found;



	spin_lock(&vfsmount_lock);

	struct vfsmount *m;



	/* extract submounts of 'mountpoint' from the expiration list */

	while ((found = select_submounts(mountpoint, &graveyard)) != 0)

		expire_mount_list(&graveyard, mounts);



	spin_unlock(&vfsmount_lock);

	while (select_submounts(mnt, &graveyard)) {

		while (!list_empty(&graveyard)) {

			m = list_first_entry(&graveyard, struct vfsmount,

						mnt_expire);

			touch_mnt_namespace(mnt->mnt_ns);

			umount_tree(mnt, 1, umounts);

		}

	}

}



EXPORT_SYMBOL_GPL(shrink_submounts);



/*

 * Some copy_from_user() implementations do not return the exact number of
@@ -1683,7 +1620,7 @@ void set_fs_pwd(struct fs_struct *fs, struct path *path) 
		path_put(&old_pwd);

}



static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)

static void chroot_fs_refs(struct path *old_root, struct path *new_root)

{

	struct task_struct *g, *p;

	struct fs_struct *fs;
@@ -1695,12 +1632,12 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) 
		if (fs) {

			atomic_inc(&fs->count);

			task_unlock(p);

			if (fs->root.dentry == old_nd->path.dentry

			    && fs->root.mnt == old_nd->path.mnt)

				set_fs_root(fs, &new_nd->path);

			if (fs->pwd.dentry == old_nd->path.dentry

			    && fs->pwd.mnt == old_nd->path.mnt)

				set_fs_pwd(fs, &new_nd->path);

			if (fs->root.dentry == old_root->dentry

			    && fs->root.mnt == old_root->mnt)

				set_fs_root(fs, new_root);

			if (fs->pwd.dentry == old_root->dentry

			    && fs->pwd.mnt == old_root->mnt)

				set_fs_pwd(fs, new_root);

			put_fs_struct(fs);

		} else

			task_unlock(p);
@@ -1737,7 +1674,8 @@ asmlinkage long sys_pivot_root(const char __user * new_root, 
			       const char __user * put_old)

{

	struct vfsmount *tmp;

	struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd;

	struct nameidata new_nd, old_nd, user_nd;

	struct path parent_path, root_parent;

	int error;



	if (!capable(CAP_SYS_ADMIN))
@@ -1811,19 +1749,19 @@ asmlinkage long sys_pivot_root(const char __user * new_root, 
			goto out3;

	} else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))

		goto out3;

	detach_mnt(new_nd.path.mnt, &parent_nd);

	detach_mnt(new_nd.path.mnt, &parent_path);

	detach_mnt(user_nd.path.mnt, &root_parent);

	/* mount old root on put_old */

	attach_mnt(user_nd.path.mnt, &old_nd);

	attach_mnt(user_nd.path.mnt, &old_nd.path);

	/* mount new_root on / */

	attach_mnt(new_nd.path.mnt, &root_parent);

	touch_mnt_namespace(current->nsproxy->mnt_ns);

	spin_unlock(&vfsmount_lock);

	chroot_fs_refs(&user_nd, &new_nd);

	chroot_fs_refs(&user_nd.path, &new_nd.path);

	security_sb_post_pivotroot(&user_nd, &new_nd);

	error = 0;

	path_put(&root_parent.path);

	path_put(&parent_nd.path);

	path_put(&root_parent);

	path_put(&parent_path);

out2:

	mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);

	up_write(&namespace_sem);

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