mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
![Christoph Hellwig](/assets/img/avatar_default.png)
Make sure a superblock really is writeable by checking MS_RDONLY under s_umount. sync_filesystems needed some re-arragement for that, but all but one sync_filesystem caller had the correct locking already so that we could add that check there. cachefiles grew s_umount locking. I've also added a WARN_ON to sync_filesystem to assert this for future callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
451 lines
12 KiB
C
451 lines
12 KiB
C
/* FS-Cache interface to CacheFiles
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public Licence
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/mount.h>
|
|
#include <linux/buffer_head.h>
|
|
#include "internal.h"
|
|
|
|
#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
|
|
|
|
struct cachefiles_lookup_data {
|
|
struct cachefiles_xattr *auxdata; /* auxiliary data */
|
|
char *key; /* key path */
|
|
};
|
|
|
|
static int cachefiles_attr_changed(struct fscache_object *_object);
|
|
|
|
/*
|
|
* allocate an object record for a cookie lookup and prepare the lookup data
|
|
*/
|
|
static struct fscache_object *cachefiles_alloc_object(
|
|
struct fscache_cache *_cache,
|
|
struct fscache_cookie *cookie)
|
|
{
|
|
struct cachefiles_lookup_data *lookup_data;
|
|
struct cachefiles_object *object;
|
|
struct cachefiles_cache *cache;
|
|
struct cachefiles_xattr *auxdata;
|
|
unsigned keylen, auxlen;
|
|
void *buffer;
|
|
char *key;
|
|
|
|
cache = container_of(_cache, struct cachefiles_cache, cache);
|
|
|
|
_enter("{%s},%p,", cache->cache.identifier, cookie);
|
|
|
|
lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL);
|
|
if (!lookup_data)
|
|
goto nomem_lookup_data;
|
|
|
|
/* create a new object record and a temporary leaf image */
|
|
object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
|
|
if (!object)
|
|
goto nomem_object;
|
|
|
|
ASSERTCMP(object->backer, ==, NULL);
|
|
|
|
BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
|
|
atomic_set(&object->usage, 1);
|
|
|
|
fscache_object_init(&object->fscache, cookie, &cache->cache);
|
|
|
|
object->type = cookie->def->type;
|
|
|
|
/* get hold of the raw key
|
|
* - stick the length on the front and leave space on the back for the
|
|
* encoder
|
|
*/
|
|
buffer = kmalloc((2 + 512) + 3, GFP_KERNEL);
|
|
if (!buffer)
|
|
goto nomem_buffer;
|
|
|
|
keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512);
|
|
ASSERTCMP(keylen, <, 512);
|
|
|
|
*(uint16_t *)buffer = keylen;
|
|
((char *)buffer)[keylen + 2] = 0;
|
|
((char *)buffer)[keylen + 3] = 0;
|
|
((char *)buffer)[keylen + 4] = 0;
|
|
|
|
/* turn the raw key into something that can work with as a filename */
|
|
key = cachefiles_cook_key(buffer, keylen + 2, object->type);
|
|
if (!key)
|
|
goto nomem_key;
|
|
|
|
/* get hold of the auxiliary data and prepend the object type */
|
|
auxdata = buffer;
|
|
auxlen = 0;
|
|
if (cookie->def->get_aux) {
|
|
auxlen = cookie->def->get_aux(cookie->netfs_data,
|
|
auxdata->data, 511);
|
|
ASSERTCMP(auxlen, <, 511);
|
|
}
|
|
|
|
auxdata->len = auxlen + 1;
|
|
auxdata->type = cookie->def->type;
|
|
|
|
lookup_data->auxdata = auxdata;
|
|
lookup_data->key = key;
|
|
object->lookup_data = lookup_data;
|
|
|
|
_leave(" = %p [%p]", &object->fscache, lookup_data);
|
|
return &object->fscache;
|
|
|
|
nomem_key:
|
|
kfree(buffer);
|
|
nomem_buffer:
|
|
BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
|
|
kmem_cache_free(cachefiles_object_jar, object);
|
|
fscache_object_destroyed(&cache->cache);
|
|
nomem_object:
|
|
kfree(lookup_data);
|
|
nomem_lookup_data:
|
|
_leave(" = -ENOMEM");
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/*
|
|
* attempt to look up the nominated node in this cache
|
|
*/
|
|
static void cachefiles_lookup_object(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_lookup_data *lookup_data;
|
|
struct cachefiles_object *parent, *object;
|
|
struct cachefiles_cache *cache;
|
|
const struct cred *saved_cred;
|
|
int ret;
|
|
|
|
_enter("{OBJ%x}", _object->debug_id);
|
|
|
|
cache = container_of(_object->cache, struct cachefiles_cache, cache);
|
|
parent = container_of(_object->parent,
|
|
struct cachefiles_object, fscache);
|
|
object = container_of(_object, struct cachefiles_object, fscache);
|
|
lookup_data = object->lookup_data;
|
|
|
|
ASSERTCMP(lookup_data, !=, NULL);
|
|
|
|
/* look up the key, creating any missing bits */
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
ret = cachefiles_walk_to_object(parent, object,
|
|
lookup_data->key,
|
|
lookup_data->auxdata);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
|
|
/* polish off by setting the attributes of non-index files */
|
|
if (ret == 0 &&
|
|
object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
|
|
cachefiles_attr_changed(&object->fscache);
|
|
|
|
if (ret < 0) {
|
|
printk(KERN_WARNING "CacheFiles: Lookup failed error %d\n",
|
|
ret);
|
|
fscache_object_lookup_error(&object->fscache);
|
|
}
|
|
|
|
_leave(" [%d]", ret);
|
|
}
|
|
|
|
/*
|
|
* indication of lookup completion
|
|
*/
|
|
static void cachefiles_lookup_complete(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_object *object;
|
|
|
|
object = container_of(_object, struct cachefiles_object, fscache);
|
|
|
|
_enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
|
|
|
|
if (object->lookup_data) {
|
|
kfree(object->lookup_data->key);
|
|
kfree(object->lookup_data->auxdata);
|
|
kfree(object->lookup_data);
|
|
object->lookup_data = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* increment the usage count on an inode object (may fail if unmounting)
|
|
*/
|
|
static
|
|
struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_object *object =
|
|
container_of(_object, struct cachefiles_object, fscache);
|
|
|
|
_enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
|
|
|
|
#ifdef CACHEFILES_DEBUG_SLAB
|
|
ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
|
|
#endif
|
|
|
|
atomic_inc(&object->usage);
|
|
return &object->fscache;
|
|
}
|
|
|
|
/*
|
|
* update the auxilliary data for an object object on disk
|
|
*/
|
|
static void cachefiles_update_object(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_object *object;
|
|
struct cachefiles_xattr *auxdata;
|
|
struct cachefiles_cache *cache;
|
|
struct fscache_cookie *cookie;
|
|
const struct cred *saved_cred;
|
|
unsigned auxlen;
|
|
|
|
_enter("{OBJ%x}", _object->debug_id);
|
|
|
|
object = container_of(_object, struct cachefiles_object, fscache);
|
|
cache = container_of(object->fscache.cache, struct cachefiles_cache,
|
|
cache);
|
|
cookie = object->fscache.cookie;
|
|
|
|
if (!cookie->def->get_aux) {
|
|
_leave(" [no aux]");
|
|
return;
|
|
}
|
|
|
|
auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL);
|
|
if (!auxdata) {
|
|
_leave(" [nomem]");
|
|
return;
|
|
}
|
|
|
|
auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
|
|
ASSERTCMP(auxlen, <, 511);
|
|
|
|
auxdata->len = auxlen + 1;
|
|
auxdata->type = cookie->def->type;
|
|
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
cachefiles_update_object_xattr(object, auxdata);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
kfree(auxdata);
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* discard the resources pinned by an object and effect retirement if
|
|
* requested
|
|
*/
|
|
static void cachefiles_drop_object(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_object *object;
|
|
struct cachefiles_cache *cache;
|
|
const struct cred *saved_cred;
|
|
|
|
ASSERT(_object);
|
|
|
|
object = container_of(_object, struct cachefiles_object, fscache);
|
|
|
|
_enter("{OBJ%x,%d}",
|
|
object->fscache.debug_id, atomic_read(&object->usage));
|
|
|
|
cache = container_of(object->fscache.cache,
|
|
struct cachefiles_cache, cache);
|
|
|
|
#ifdef CACHEFILES_DEBUG_SLAB
|
|
ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
|
|
#endif
|
|
|
|
/* delete retired objects */
|
|
if (object->fscache.state == FSCACHE_OBJECT_RECYCLING &&
|
|
_object != cache->cache.fsdef
|
|
) {
|
|
_debug("- retire object OBJ%x", object->fscache.debug_id);
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
cachefiles_delete_object(cache, object);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
}
|
|
|
|
/* close the filesystem stuff attached to the object */
|
|
if (object->backer != object->dentry)
|
|
dput(object->backer);
|
|
object->backer = NULL;
|
|
|
|
/* note that the object is now inactive */
|
|
if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
|
|
write_lock(&cache->active_lock);
|
|
if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE,
|
|
&object->flags))
|
|
BUG();
|
|
rb_erase(&object->active_node, &cache->active_nodes);
|
|
wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
|
|
write_unlock(&cache->active_lock);
|
|
}
|
|
|
|
dput(object->dentry);
|
|
object->dentry = NULL;
|
|
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* dispose of a reference to an object
|
|
*/
|
|
static void cachefiles_put_object(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_object *object;
|
|
struct fscache_cache *cache;
|
|
|
|
ASSERT(_object);
|
|
|
|
object = container_of(_object, struct cachefiles_object, fscache);
|
|
|
|
_enter("{OBJ%x,%d}",
|
|
object->fscache.debug_id, atomic_read(&object->usage));
|
|
|
|
#ifdef CACHEFILES_DEBUG_SLAB
|
|
ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
|
|
#endif
|
|
|
|
ASSERTIFCMP(object->fscache.parent,
|
|
object->fscache.parent->n_children, >, 0);
|
|
|
|
if (atomic_dec_and_test(&object->usage)) {
|
|
_debug("- kill object OBJ%x", object->fscache.debug_id);
|
|
|
|
ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
|
|
ASSERTCMP(object->fscache.parent, ==, NULL);
|
|
ASSERTCMP(object->backer, ==, NULL);
|
|
ASSERTCMP(object->dentry, ==, NULL);
|
|
ASSERTCMP(object->fscache.n_ops, ==, 0);
|
|
ASSERTCMP(object->fscache.n_children, ==, 0);
|
|
|
|
if (object->lookup_data) {
|
|
kfree(object->lookup_data->key);
|
|
kfree(object->lookup_data->auxdata);
|
|
kfree(object->lookup_data);
|
|
object->lookup_data = NULL;
|
|
}
|
|
|
|
cache = object->fscache.cache;
|
|
kmem_cache_free(cachefiles_object_jar, object);
|
|
fscache_object_destroyed(cache);
|
|
}
|
|
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* sync a cache
|
|
*/
|
|
static void cachefiles_sync_cache(struct fscache_cache *_cache)
|
|
{
|
|
struct cachefiles_cache *cache;
|
|
const struct cred *saved_cred;
|
|
int ret;
|
|
|
|
_enter("%p", _cache);
|
|
|
|
cache = container_of(_cache, struct cachefiles_cache, cache);
|
|
|
|
/* make sure all pages pinned by operations on behalf of the netfs are
|
|
* written to disc */
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
down_read(&cache->mnt->mnt_sb->s_umount);
|
|
ret = sync_filesystem(cache->mnt->mnt_sb);
|
|
up_read(&cache->mnt->mnt_sb->s_umount);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
|
|
if (ret == -EIO)
|
|
cachefiles_io_error(cache,
|
|
"Attempt to sync backing fs superblock"
|
|
" returned error %d",
|
|
ret);
|
|
}
|
|
|
|
/*
|
|
* notification the attributes on an object have changed
|
|
* - called with reads/writes excluded by FS-Cache
|
|
*/
|
|
static int cachefiles_attr_changed(struct fscache_object *_object)
|
|
{
|
|
struct cachefiles_object *object;
|
|
struct cachefiles_cache *cache;
|
|
const struct cred *saved_cred;
|
|
struct iattr newattrs;
|
|
uint64_t ni_size;
|
|
loff_t oi_size;
|
|
int ret;
|
|
|
|
_object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size);
|
|
|
|
_enter("{OBJ%x},[%llu]",
|
|
_object->debug_id, (unsigned long long) ni_size);
|
|
|
|
object = container_of(_object, struct cachefiles_object, fscache);
|
|
cache = container_of(object->fscache.cache,
|
|
struct cachefiles_cache, cache);
|
|
|
|
if (ni_size == object->i_size)
|
|
return 0;
|
|
|
|
if (!object->backer)
|
|
return -ENOBUFS;
|
|
|
|
ASSERT(S_ISREG(object->backer->d_inode->i_mode));
|
|
|
|
fscache_set_store_limit(&object->fscache, ni_size);
|
|
|
|
oi_size = i_size_read(object->backer->d_inode);
|
|
if (oi_size == ni_size)
|
|
return 0;
|
|
|
|
newattrs.ia_size = ni_size;
|
|
newattrs.ia_valid = ATTR_SIZE;
|
|
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
mutex_lock(&object->backer->d_inode->i_mutex);
|
|
ret = notify_change(object->backer, &newattrs);
|
|
mutex_unlock(&object->backer->d_inode->i_mutex);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
|
|
if (ret == -EIO) {
|
|
fscache_set_store_limit(&object->fscache, 0);
|
|
cachefiles_io_error_obj(object, "Size set failed");
|
|
ret = -ENOBUFS;
|
|
}
|
|
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* dissociate a cache from all the pages it was backing
|
|
*/
|
|
static void cachefiles_dissociate_pages(struct fscache_cache *cache)
|
|
{
|
|
_enter("");
|
|
}
|
|
|
|
const struct fscache_cache_ops cachefiles_cache_ops = {
|
|
.name = "cachefiles",
|
|
.alloc_object = cachefiles_alloc_object,
|
|
.lookup_object = cachefiles_lookup_object,
|
|
.lookup_complete = cachefiles_lookup_complete,
|
|
.grab_object = cachefiles_grab_object,
|
|
.update_object = cachefiles_update_object,
|
|
.drop_object = cachefiles_drop_object,
|
|
.put_object = cachefiles_put_object,
|
|
.sync_cache = cachefiles_sync_cache,
|
|
.attr_changed = cachefiles_attr_changed,
|
|
.read_or_alloc_page = cachefiles_read_or_alloc_page,
|
|
.read_or_alloc_pages = cachefiles_read_or_alloc_pages,
|
|
.allocate_page = cachefiles_allocate_page,
|
|
.allocate_pages = cachefiles_allocate_pages,
|
|
.write_page = cachefiles_write_page,
|
|
.uncache_page = cachefiles_uncache_page,
|
|
.dissociate_pages = cachefiles_dissociate_pages,
|
|
};
|