Commit eacb58fd authored by Al Viro's avatar Al Viro
Browse files

binfmt_misc: switch to locked_recursive_removal() 



... fixing a mount leak, strictly speaking.

Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8c0e092e

fs/binfmt_misc.c

+3 −41
Original line number Diff line number Diff line
@@ -674,44 +674,6 @@ static void bm_evict_inode(struct inode *inode) 
	}

}



/**

 * unlink_binfmt_dentry - remove the dentry for the binary type handler

 * @dentry: dentry associated with the binary type handler

 *

 * Do the actual filesystem work to remove a dentry for a registered binary

 * type handler. Since binfmt_misc only allows simple files to be created

 * directly under the root dentry of the filesystem we ensure that we are

 * indeed passed a dentry directly beneath the root dentry, that the inode

 * associated with the root dentry is locked, and that it is a regular file we

 * are asked to remove.

 */

static void unlink_binfmt_dentry(struct dentry *dentry)

{

	struct dentry *parent = dentry->d_parent;

	struct inode *inode, *parent_inode;



	/* All entries are immediate descendants of the root dentry. */

	if (WARN_ON_ONCE(dentry->d_sb->s_root != parent))

		return;



	/* We only expect to be called on regular files. */

	inode = d_inode(dentry);

	if (WARN_ON_ONCE(!S_ISREG(inode->i_mode)))

		return;



	/* The parent inode must be locked. */

	parent_inode = d_inode(parent);

	if (WARN_ON_ONCE(!inode_is_locked(parent_inode)))

		return;



	if (simple_positive(dentry)) {

		dget(dentry);

		simple_unlink(parent_inode, dentry);

		d_delete(dentry);

		dput(dentry);

	}

}



/**

 * remove_binfmt_handler - remove a binary type handler

 * @misc: handle to binfmt_misc instance
@@ -729,7 +691,7 @@ static void remove_binfmt_handler(struct binfmt_misc *misc, Node *e) 
	write_lock(&misc->entries_lock);

	list_del_init(&e->list);

	write_unlock(&misc->entries_lock);

	unlink_binfmt_dentry(e->dentry);

	locked_recursive_removal(e->dentry, NULL);

}



/* /<entry> */
@@ -772,7 +734,7 @@ static ssize_t bm_entry_write(struct file *file, const char __user *buffer, 
	case 3:

		/* Delete this handler. */

		inode = d_inode(inode->i_sb->s_root);

		inode_lock(inode);

		inode_lock_nested(inode, I_MUTEX_PARENT);



		/*

		 * In order to add new element or remove elements from the list
@@ -922,7 +884,7 @@ static ssize_t bm_status_write(struct file *file, const char __user *buffer, 
	case 3:

		/* Delete all handlers. */

		inode = d_inode(file_inode(file)->i_sb->s_root);

		inode_lock(inode);

		inode_lock_nested(inode, I_MUTEX_PARENT);



		/*

		 * In order to add new element or remove elements from the list