linux/fs/cachefiles/namei.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* CacheFiles path walking and related routines
 *
 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include "internal.h"

/*
 * Mark the backing file as being a cache file if it's not already in use.  The
 * mark tells the culling request command that it's not allowed to cull the
 * file or directory.  The caller must hold the inode lock.
 */
static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
					   struct inode *inode)
{ … }

static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
					 struct inode *inode)
{ … }

/*
 * Unmark a backing inode.  The caller must hold the inode lock.
 */
static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
					     struct inode *inode)
{ … }

static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
					      struct inode *inode)
{ … }

/*
 * Unmark a backing inode and tell cachefilesd that there's something that can
 * be culled.
 */
void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
				    struct file *file)
{ … }

/*
 * get a subdirectory
 */
struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
					struct dentry *dir,
					const char *dirname,
					bool *_is_new)
{ … }

/*
 * Put a subdirectory.
 */
void cachefiles_put_directory(struct dentry *dir)
{ … }

/*
 * Remove a regular file from the cache.
 */
static int cachefiles_unlink(struct cachefiles_cache *cache,
			     struct cachefiles_object *object,
			     struct dentry *dir, struct dentry *dentry,
			     enum fscache_why_object_killed why)
{ … }

/*
 * Delete an object representation from the cache
 * - File backed objects are unlinked
 * - Directory backed objects are stuffed into the graveyard for userspace to
 *   delete
 */
int cachefiles_bury_object(struct cachefiles_cache *cache,
			   struct cachefiles_object *object,
			   struct dentry *dir,
			   struct dentry *rep,
			   enum fscache_why_object_killed why)
{ … }

/*
 * Delete a cache file.
 */
int cachefiles_delete_object(struct cachefiles_object *object,
			     enum fscache_why_object_killed why)
{ … }

/*
 * Create a temporary file and leave it unattached and un-xattr'd until the
 * time comes to discard the object from memory.
 */
struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
{ … }

/*
 * Create a new file.
 */
static bool cachefiles_create_file(struct cachefiles_object *object)
{ … }

/*
 * Open an existing file, checking its attributes and replacing it if it is
 * stale.
 */
static bool cachefiles_open_file(struct cachefiles_object *object,
				 struct dentry *dentry)
{ … }

/*
 * walk from the parent object to the child object through the backing
 * filesystem, creating directories as we go
 */
bool cachefiles_look_up_object(struct cachefiles_object *object)
{ … }

/*
 * Attempt to link a temporary file into its rightful place in the cache.
 */
bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
			       struct cachefiles_object *object)
{ … }

/*
 * Look up an inode to be checked or culled.  Return -EBUSY if the inode is
 * marked in use.
 */
static struct dentry *cachefiles_lookup_for_cull(struct cachefiles_cache *cache,
						 struct dentry *dir,
						 char *filename)
{ … }

/*
 * Cull an object if it's not in use
 * - called only by cache manager daemon
 */
int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
		    char *filename)
{ … }

/*
 * Find out if an object is in use or not
 * - called only by cache manager daemon
 * - returns -EBUSY or 0 to indicate whether an object is in use or not
 */
int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
			    char *filename)
{ … }