mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![David Howells](/assets/img/avatar_default.png)
The type of a->key[0] is char in fscache_volume_same(). If the length
of cache volume key is greater than 127, the value of a->key[0] is less
than 0. In this case, klen becomes much larger than 255 after type
conversion, because the type of klen is size_t. As a result, memcmp()
is read out of bounds.
This causes a slab-out-of-bounds Read in __fscache_acquire_volume(), as
reported by Syzbot.
Fix this by changing the type of the stored key to "u8 *" rather than
"char *" (it isn't a simple string anyway). Also put in a check that
the volume name doesn't exceed NAME_MAX.
BUG: KASAN: slab-out-of-bounds in memcmp+0x16f/0x1c0 lib/string.c:757
Read of size 8 at addr ffff888016f3aa90 by task syz-executor344/3613
Call Trace:
memcmp+0x16f/0x1c0 lib/string.c:757
memcmp include/linux/fortify-string.h:420 [inline]
fscache_volume_same fs/fscache/volume.c:133 [inline]
fscache_hash_volume fs/fscache/volume.c:171 [inline]
__fscache_acquire_volume+0x76c/0x1080 fs/fscache/volume.c:328
fscache_acquire_volume include/linux/fscache.h:204 [inline]
v9fs_cache_session_get_cookie+0x143/0x240 fs/9p/cache.c:34
v9fs_session_init+0x1166/0x1810 fs/9p/v9fs.c:473
v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1530
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x1326/0x1e20 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
Fixes: 62ab633523
("fscache: Implement volume registration")
Reported-by: syzbot+a76f6a6e524cf2080aa3@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Zhang Peng <zhangpeng362@huawei.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/Y3OH+Dmi0QIOK18n@codewreck.org/ # Zhang Peng's v1 fix
Link: https://lore.kernel.org/r/20221115140447.2971680-1-zhangpeng362@huawei.com/ # Zhang Peng's v2 fix
Link: https://lore.kernel.org/r/166869954095.3793579.8500020902371015443.stgit@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
695 lines
25 KiB
C
695 lines
25 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/* General filesystem caching interface
|
|
*
|
|
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* NOTE!!! See:
|
|
*
|
|
* Documentation/filesystems/caching/netfs-api.rst
|
|
*
|
|
* for a description of the network filesystem interface declared here.
|
|
*/
|
|
|
|
#ifndef _LINUX_FSCACHE_H
|
|
#define _LINUX_FSCACHE_H
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/netfs.h>
|
|
#include <linux/writeback.h>
|
|
|
|
#if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
|
|
#define __fscache_available (1)
|
|
#define fscache_available() (1)
|
|
#define fscache_volume_valid(volume) (volume)
|
|
#define fscache_cookie_valid(cookie) (cookie)
|
|
#define fscache_resources_valid(cres) ((cres)->cache_priv)
|
|
#define fscache_cookie_enabled(cookie) (cookie && !test_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags))
|
|
#else
|
|
#define __fscache_available (0)
|
|
#define fscache_available() (0)
|
|
#define fscache_volume_valid(volume) (0)
|
|
#define fscache_cookie_valid(cookie) (0)
|
|
#define fscache_resources_valid(cres) (false)
|
|
#define fscache_cookie_enabled(cookie) (0)
|
|
#endif
|
|
|
|
struct fscache_cookie;
|
|
|
|
#define FSCACHE_ADV_SINGLE_CHUNK 0x01 /* The object is a single chunk of data */
|
|
#define FSCACHE_ADV_WRITE_CACHE 0x00 /* Do cache if written to locally */
|
|
#define FSCACHE_ADV_WRITE_NOCACHE 0x02 /* Don't cache if written to locally */
|
|
#define FSCACHE_ADV_WANT_CACHE_SIZE 0x04 /* Retrieve cache size at runtime */
|
|
|
|
#define FSCACHE_INVAL_DIO_WRITE 0x01 /* Invalidate due to DIO write */
|
|
|
|
enum fscache_want_state {
|
|
FSCACHE_WANT_PARAMS,
|
|
FSCACHE_WANT_WRITE,
|
|
FSCACHE_WANT_READ,
|
|
};
|
|
|
|
/*
|
|
* Data object state.
|
|
*/
|
|
enum fscache_cookie_state {
|
|
FSCACHE_COOKIE_STATE_QUIESCENT, /* The cookie is uncached */
|
|
FSCACHE_COOKIE_STATE_LOOKING_UP, /* The cache object is being looked up */
|
|
FSCACHE_COOKIE_STATE_CREATING, /* The cache object is being created */
|
|
FSCACHE_COOKIE_STATE_ACTIVE, /* The cache is active, readable and writable */
|
|
FSCACHE_COOKIE_STATE_INVALIDATING, /* The cache is being invalidated */
|
|
FSCACHE_COOKIE_STATE_FAILED, /* The cache failed, withdraw to clear */
|
|
FSCACHE_COOKIE_STATE_LRU_DISCARDING, /* The cookie is being discarded by the LRU */
|
|
FSCACHE_COOKIE_STATE_WITHDRAWING, /* The cookie is being withdrawn */
|
|
FSCACHE_COOKIE_STATE_RELINQUISHING, /* The cookie is being relinquished */
|
|
FSCACHE_COOKIE_STATE_DROPPED, /* The cookie has been dropped */
|
|
#define FSCACHE_COOKIE_STATE__NR (FSCACHE_COOKIE_STATE_DROPPED + 1)
|
|
} __attribute__((mode(byte)));
|
|
|
|
/*
|
|
* Volume representation cookie.
|
|
*/
|
|
struct fscache_volume {
|
|
refcount_t ref;
|
|
atomic_t n_cookies; /* Number of data cookies in volume */
|
|
atomic_t n_accesses; /* Number of cache accesses in progress */
|
|
unsigned int debug_id;
|
|
unsigned int key_hash; /* Hash of key string */
|
|
u8 *key; /* Volume ID, eg. "afs@example.com@1234" */
|
|
struct list_head proc_link; /* Link in /proc/fs/fscache/volumes */
|
|
struct hlist_bl_node hash_link; /* Link in hash table */
|
|
struct work_struct work;
|
|
struct fscache_cache *cache; /* The cache in which this resides */
|
|
void *cache_priv; /* Cache private data */
|
|
spinlock_t lock;
|
|
unsigned long flags;
|
|
#define FSCACHE_VOLUME_RELINQUISHED 0 /* Volume is being cleaned up */
|
|
#define FSCACHE_VOLUME_INVALIDATE 1 /* Volume was invalidated */
|
|
#define FSCACHE_VOLUME_COLLIDED_WITH 2 /* Volume was collided with */
|
|
#define FSCACHE_VOLUME_ACQUIRE_PENDING 3 /* Volume is waiting to complete acquisition */
|
|
#define FSCACHE_VOLUME_CREATING 4 /* Volume is being created on disk */
|
|
u8 coherency_len; /* Length of the coherency data */
|
|
u8 coherency[]; /* Coherency data */
|
|
};
|
|
|
|
/*
|
|
* Data file representation cookie.
|
|
* - a file will only appear in one cache
|
|
* - a request to cache a file may or may not be honoured, subject to
|
|
* constraints such as disk space
|
|
* - indices are created on disk just-in-time
|
|
*/
|
|
struct fscache_cookie {
|
|
refcount_t ref;
|
|
atomic_t n_active; /* number of active users of cookie */
|
|
atomic_t n_accesses; /* Number of cache accesses in progress */
|
|
unsigned int debug_id;
|
|
unsigned int inval_counter; /* Number of invalidations made */
|
|
spinlock_t lock;
|
|
struct fscache_volume *volume; /* Parent volume of this file. */
|
|
void *cache_priv; /* Cache-side representation */
|
|
struct hlist_bl_node hash_link; /* Link in hash table */
|
|
struct list_head proc_link; /* Link in proc list */
|
|
struct list_head commit_link; /* Link in commit queue */
|
|
struct work_struct work; /* Commit/relinq/withdraw work */
|
|
loff_t object_size; /* Size of the netfs object */
|
|
unsigned long unused_at; /* Time at which unused (jiffies) */
|
|
unsigned long flags;
|
|
#define FSCACHE_COOKIE_RELINQUISHED 0 /* T if cookie has been relinquished */
|
|
#define FSCACHE_COOKIE_RETIRED 1 /* T if this cookie has retired on relinq */
|
|
#define FSCACHE_COOKIE_IS_CACHING 2 /* T if this cookie is cached */
|
|
#define FSCACHE_COOKIE_NO_DATA_TO_READ 3 /* T if this cookie has nothing to read */
|
|
#define FSCACHE_COOKIE_NEEDS_UPDATE 4 /* T if attrs have been updated */
|
|
#define FSCACHE_COOKIE_HAS_BEEN_CACHED 5 /* T if cookie needs withdraw-on-relinq */
|
|
#define FSCACHE_COOKIE_DISABLED 6 /* T if cookie has been disabled */
|
|
#define FSCACHE_COOKIE_LOCAL_WRITE 7 /* T if cookie has been modified locally */
|
|
#define FSCACHE_COOKIE_NO_ACCESS_WAKE 8 /* T if no wake when n_accesses goes 0 */
|
|
#define FSCACHE_COOKIE_DO_RELINQUISH 9 /* T if this cookie needs relinquishment */
|
|
#define FSCACHE_COOKIE_DO_WITHDRAW 10 /* T if this cookie needs withdrawing */
|
|
#define FSCACHE_COOKIE_DO_LRU_DISCARD 11 /* T if this cookie needs LRU discard */
|
|
#define FSCACHE_COOKIE_DO_PREP_TO_WRITE 12 /* T if cookie needs write preparation */
|
|
#define FSCACHE_COOKIE_HAVE_DATA 13 /* T if this cookie has data stored */
|
|
#define FSCACHE_COOKIE_IS_HASHED 14 /* T if this cookie is hashed */
|
|
#define FSCACHE_COOKIE_DO_INVALIDATE 15 /* T if cookie needs invalidation */
|
|
|
|
enum fscache_cookie_state state;
|
|
u8 advice; /* FSCACHE_ADV_* */
|
|
u8 key_len; /* Length of index key */
|
|
u8 aux_len; /* Length of auxiliary data */
|
|
u32 key_hash; /* Hash of volume, key, len */
|
|
union {
|
|
void *key; /* Index key */
|
|
u8 inline_key[16]; /* - If the key is short enough */
|
|
};
|
|
union {
|
|
void *aux; /* Auxiliary data */
|
|
u8 inline_aux[8]; /* - If the aux data is short enough */
|
|
};
|
|
};
|
|
|
|
/*
|
|
* slow-path functions for when there is actually caching available, and the
|
|
* netfs does actually have a valid token
|
|
* - these are not to be called directly
|
|
* - these are undefined symbols when FS-Cache is not configured and the
|
|
* optimiser takes care of not using them
|
|
*/
|
|
extern struct fscache_volume *__fscache_acquire_volume(const char *, const char *,
|
|
const void *, size_t);
|
|
extern void __fscache_relinquish_volume(struct fscache_volume *, const void *, bool);
|
|
|
|
extern struct fscache_cookie *__fscache_acquire_cookie(
|
|
struct fscache_volume *,
|
|
u8,
|
|
const void *, size_t,
|
|
const void *, size_t,
|
|
loff_t);
|
|
extern void __fscache_use_cookie(struct fscache_cookie *, bool);
|
|
extern void __fscache_unuse_cookie(struct fscache_cookie *, const void *, const loff_t *);
|
|
extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool);
|
|
extern void __fscache_resize_cookie(struct fscache_cookie *, loff_t);
|
|
extern void __fscache_invalidate(struct fscache_cookie *, const void *, loff_t, unsigned int);
|
|
extern int __fscache_begin_read_operation(struct netfs_cache_resources *, struct fscache_cookie *);
|
|
extern int __fscache_begin_write_operation(struct netfs_cache_resources *, struct fscache_cookie *);
|
|
|
|
extern void __fscache_write_to_cache(struct fscache_cookie *, struct address_space *,
|
|
loff_t, size_t, loff_t, netfs_io_terminated_t, void *,
|
|
bool);
|
|
extern void __fscache_clear_page_bits(struct address_space *, loff_t, size_t);
|
|
|
|
/**
|
|
* fscache_acquire_volume - Register a volume as desiring caching services
|
|
* @volume_key: An identification string for the volume
|
|
* @cache_name: The name of the cache to use (or NULL for the default)
|
|
* @coherency_data: Piece of arbitrary coherency data to check (or NULL)
|
|
* @coherency_len: The size of the coherency data
|
|
*
|
|
* Register a volume as desiring caching services if they're available. The
|
|
* caller must provide an identifier for the volume and may also indicate which
|
|
* cache it should be in. If a preexisting volume entry is found in the cache,
|
|
* the coherency data must match otherwise the entry will be invalidated.
|
|
*
|
|
* Returns a cookie pointer on success, -ENOMEM if out of memory or -EBUSY if a
|
|
* cache volume of that name is already acquired. Note that "NULL" is a valid
|
|
* cookie pointer and can be returned if caching is refused.
|
|
*/
|
|
static inline
|
|
struct fscache_volume *fscache_acquire_volume(const char *volume_key,
|
|
const char *cache_name,
|
|
const void *coherency_data,
|
|
size_t coherency_len)
|
|
{
|
|
if (!fscache_available())
|
|
return NULL;
|
|
return __fscache_acquire_volume(volume_key, cache_name,
|
|
coherency_data, coherency_len);
|
|
}
|
|
|
|
/**
|
|
* fscache_relinquish_volume - Cease caching a volume
|
|
* @volume: The volume cookie
|
|
* @coherency_data: Piece of arbitrary coherency data to set (or NULL)
|
|
* @invalidate: True if the volume should be invalidated
|
|
*
|
|
* Indicate that a filesystem no longer desires caching services for a volume.
|
|
* The caller must have relinquished all file cookies prior to calling this.
|
|
* The stored coherency data is updated.
|
|
*/
|
|
static inline
|
|
void fscache_relinquish_volume(struct fscache_volume *volume,
|
|
const void *coherency_data,
|
|
bool invalidate)
|
|
{
|
|
if (fscache_volume_valid(volume))
|
|
__fscache_relinquish_volume(volume, coherency_data, invalidate);
|
|
}
|
|
|
|
/**
|
|
* fscache_acquire_cookie - Acquire a cookie to represent a cache object
|
|
* @volume: The volume in which to locate/create this cookie
|
|
* @advice: Advice flags (FSCACHE_COOKIE_ADV_*)
|
|
* @index_key: The index key for this cookie
|
|
* @index_key_len: Size of the index key
|
|
* @aux_data: The auxiliary data for the cookie (may be NULL)
|
|
* @aux_data_len: Size of the auxiliary data buffer
|
|
* @object_size: The initial size of object
|
|
*
|
|
* Acquire a cookie to represent a data file within the given cache volume.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.rst for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
struct fscache_cookie *fscache_acquire_cookie(struct fscache_volume *volume,
|
|
u8 advice,
|
|
const void *index_key,
|
|
size_t index_key_len,
|
|
const void *aux_data,
|
|
size_t aux_data_len,
|
|
loff_t object_size)
|
|
{
|
|
if (!fscache_volume_valid(volume))
|
|
return NULL;
|
|
return __fscache_acquire_cookie(volume, advice,
|
|
index_key, index_key_len,
|
|
aux_data, aux_data_len,
|
|
object_size);
|
|
}
|
|
|
|
/**
|
|
* fscache_use_cookie - Request usage of cookie attached to an object
|
|
* @cookie: The cookie representing the cache object
|
|
* @will_modify: If cache is expected to be modified locally
|
|
*
|
|
* Request usage of the cookie attached to an object. The caller should tell
|
|
* the cache if the object's contents are about to be modified locally and then
|
|
* the cache can apply the policy that has been set to handle this case.
|
|
*/
|
|
static inline void fscache_use_cookie(struct fscache_cookie *cookie,
|
|
bool will_modify)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
__fscache_use_cookie(cookie, will_modify);
|
|
}
|
|
|
|
/**
|
|
* fscache_unuse_cookie - Cease usage of cookie attached to an object
|
|
* @cookie: The cookie representing the cache object
|
|
* @aux_data: Updated auxiliary data (or NULL)
|
|
* @object_size: Revised size of the object (or NULL)
|
|
*
|
|
* Cease usage of the cookie attached to an object. When the users count
|
|
* reaches zero then the cookie relinquishment will be permitted to proceed.
|
|
*/
|
|
static inline void fscache_unuse_cookie(struct fscache_cookie *cookie,
|
|
const void *aux_data,
|
|
const loff_t *object_size)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
__fscache_unuse_cookie(cookie, aux_data, object_size);
|
|
}
|
|
|
|
/**
|
|
* fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding
|
|
* it
|
|
* @cookie: The cookie being returned
|
|
* @retire: True if the cache object the cookie represents is to be discarded
|
|
*
|
|
* This function returns a cookie to the cache, forcibly discarding the
|
|
* associated cache object if retire is set to true.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.rst for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
void fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
__fscache_relinquish_cookie(cookie, retire);
|
|
}
|
|
|
|
/*
|
|
* Find the auxiliary data on a cookie.
|
|
*/
|
|
static inline void *fscache_get_aux(struct fscache_cookie *cookie)
|
|
{
|
|
if (cookie->aux_len <= sizeof(cookie->inline_aux))
|
|
return cookie->inline_aux;
|
|
else
|
|
return cookie->aux;
|
|
}
|
|
|
|
/*
|
|
* Update the auxiliary data on a cookie.
|
|
*/
|
|
static inline
|
|
void fscache_update_aux(struct fscache_cookie *cookie,
|
|
const void *aux_data, const loff_t *object_size)
|
|
{
|
|
void *p = fscache_get_aux(cookie);
|
|
|
|
if (aux_data && p)
|
|
memcpy(p, aux_data, cookie->aux_len);
|
|
if (object_size)
|
|
cookie->object_size = *object_size;
|
|
}
|
|
|
|
#ifdef CONFIG_FSCACHE_STATS
|
|
extern atomic_t fscache_n_updates;
|
|
#endif
|
|
|
|
static inline
|
|
void __fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data,
|
|
const loff_t *object_size)
|
|
{
|
|
#ifdef CONFIG_FSCACHE_STATS
|
|
atomic_inc(&fscache_n_updates);
|
|
#endif
|
|
fscache_update_aux(cookie, aux_data, object_size);
|
|
smp_wmb();
|
|
set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
|
|
}
|
|
|
|
/**
|
|
* fscache_update_cookie - Request that a cache object be updated
|
|
* @cookie: The cookie representing the cache object
|
|
* @aux_data: The updated auxiliary data for the cookie (may be NULL)
|
|
* @object_size: The current size of the object (may be NULL)
|
|
*
|
|
* Request an update of the index data for the cache object associated with the
|
|
* cookie. The auxiliary data on the cookie will be updated first if @aux_data
|
|
* is set and the object size will be updated and the object possibly trimmed
|
|
* if @object_size is set.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.rst for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
void fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data,
|
|
const loff_t *object_size)
|
|
{
|
|
if (fscache_cookie_enabled(cookie))
|
|
__fscache_update_cookie(cookie, aux_data, object_size);
|
|
}
|
|
|
|
/**
|
|
* fscache_resize_cookie - Request that a cache object be resized
|
|
* @cookie: The cookie representing the cache object
|
|
* @new_size: The new size of the object (may be NULL)
|
|
*
|
|
* Request that the size of an object be changed.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.rst for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
void fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size)
|
|
{
|
|
if (fscache_cookie_enabled(cookie))
|
|
__fscache_resize_cookie(cookie, new_size);
|
|
}
|
|
|
|
/**
|
|
* fscache_invalidate - Notify cache that an object needs invalidation
|
|
* @cookie: The cookie representing the cache object
|
|
* @aux_data: The updated auxiliary data for the cookie (may be NULL)
|
|
* @size: The revised size of the object.
|
|
* @flags: Invalidation flags (FSCACHE_INVAL_*)
|
|
*
|
|
* Notify the cache that an object is needs to be invalidated and that it
|
|
* should abort any retrievals or stores it is doing on the cache. This
|
|
* increments inval_counter on the cookie which can be used by the caller to
|
|
* reconsider I/O requests as they complete.
|
|
*
|
|
* If @flags has FSCACHE_INVAL_DIO_WRITE set, this indicates that this is due
|
|
* to a direct I/O write and will cause caching to be disabled on this cookie
|
|
* until it is completely unused.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.rst for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
void fscache_invalidate(struct fscache_cookie *cookie,
|
|
const void *aux_data, loff_t size, unsigned int flags)
|
|
{
|
|
if (fscache_cookie_enabled(cookie))
|
|
__fscache_invalidate(cookie, aux_data, size, flags);
|
|
}
|
|
|
|
/**
|
|
* fscache_operation_valid - Return true if operations resources are usable
|
|
* @cres: The resources to check.
|
|
*
|
|
* Returns a pointer to the operations table if usable or NULL if not.
|
|
*/
|
|
static inline
|
|
const struct netfs_cache_ops *fscache_operation_valid(const struct netfs_cache_resources *cres)
|
|
{
|
|
return fscache_resources_valid(cres) ? cres->ops : NULL;
|
|
}
|
|
|
|
/**
|
|
* fscache_begin_read_operation - Begin a read operation for the netfs lib
|
|
* @cres: The cache resources for the read being performed
|
|
* @cookie: The cookie representing the cache object
|
|
*
|
|
* Begin a read operation on behalf of the netfs helper library. @cres
|
|
* indicates the cache resources to which the operation state should be
|
|
* attached; @cookie indicates the cache object that will be accessed.
|
|
*
|
|
* This is intended to be called from the ->begin_cache_operation() netfs lib
|
|
* operation as implemented by the network filesystem.
|
|
*
|
|
* @cres->inval_counter is set from @cookie->inval_counter for comparison at
|
|
* the end of the operation. This allows invalidation during the operation to
|
|
* be detected by the caller.
|
|
*
|
|
* Returns:
|
|
* * 0 - Success
|
|
* * -ENOBUFS - No caching available
|
|
* * Other error code from the cache, such as -ENOMEM.
|
|
*/
|
|
static inline
|
|
int fscache_begin_read_operation(struct netfs_cache_resources *cres,
|
|
struct fscache_cookie *cookie)
|
|
{
|
|
if (fscache_cookie_enabled(cookie))
|
|
return __fscache_begin_read_operation(cres, cookie);
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
/**
|
|
* fscache_end_operation - End the read operation for the netfs lib
|
|
* @cres: The cache resources for the read operation
|
|
*
|
|
* Clean up the resources at the end of the read request.
|
|
*/
|
|
static inline void fscache_end_operation(struct netfs_cache_resources *cres)
|
|
{
|
|
const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
|
|
|
|
if (ops)
|
|
ops->end_operation(cres);
|
|
}
|
|
|
|
/**
|
|
* fscache_read - Start a read from the cache.
|
|
* @cres: The cache resources to use
|
|
* @start_pos: The beginning file offset in the cache file
|
|
* @iter: The buffer to fill - and also the length
|
|
* @read_hole: How to handle a hole in the data.
|
|
* @term_func: The function to call upon completion
|
|
* @term_func_priv: The private data for @term_func
|
|
*
|
|
* Start a read from the cache. @cres indicates the cache object to read from
|
|
* and must be obtained by a call to fscache_begin_operation() beforehand.
|
|
*
|
|
* The data is read into the iterator, @iter, and that also indicates the size
|
|
* of the operation. @start_pos is the start position in the file, though if
|
|
* @seek_data is set appropriately, the cache can use SEEK_DATA to find the
|
|
* next piece of data, writing zeros for the hole into the iterator.
|
|
*
|
|
* Upon termination of the operation, @term_func will be called and supplied
|
|
* with @term_func_priv plus the amount of data written, if successful, or the
|
|
* error code otherwise.
|
|
*
|
|
* @read_hole indicates how a partially populated region in the cache should be
|
|
* handled. It can be one of a number of settings:
|
|
*
|
|
* NETFS_READ_HOLE_IGNORE - Just try to read (may return a short read).
|
|
*
|
|
* NETFS_READ_HOLE_CLEAR - Seek for data, clearing the part of the buffer
|
|
* skipped over, then do as for IGNORE.
|
|
*
|
|
* NETFS_READ_HOLE_FAIL - Give ENODATA if we encounter a hole.
|
|
*/
|
|
static inline
|
|
int fscache_read(struct netfs_cache_resources *cres,
|
|
loff_t start_pos,
|
|
struct iov_iter *iter,
|
|
enum netfs_read_from_hole read_hole,
|
|
netfs_io_terminated_t term_func,
|
|
void *term_func_priv)
|
|
{
|
|
const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
|
|
return ops->read(cres, start_pos, iter, read_hole,
|
|
term_func, term_func_priv);
|
|
}
|
|
|
|
/**
|
|
* fscache_begin_write_operation - Begin a write operation for the netfs lib
|
|
* @cres: The cache resources for the write being performed
|
|
* @cookie: The cookie representing the cache object
|
|
*
|
|
* Begin a write operation on behalf of the netfs helper library. @cres
|
|
* indicates the cache resources to which the operation state should be
|
|
* attached; @cookie indicates the cache object that will be accessed.
|
|
*
|
|
* @cres->inval_counter is set from @cookie->inval_counter for comparison at
|
|
* the end of the operation. This allows invalidation during the operation to
|
|
* be detected by the caller.
|
|
*
|
|
* Returns:
|
|
* * 0 - Success
|
|
* * -ENOBUFS - No caching available
|
|
* * Other error code from the cache, such as -ENOMEM.
|
|
*/
|
|
static inline
|
|
int fscache_begin_write_operation(struct netfs_cache_resources *cres,
|
|
struct fscache_cookie *cookie)
|
|
{
|
|
if (fscache_cookie_enabled(cookie))
|
|
return __fscache_begin_write_operation(cres, cookie);
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
/**
|
|
* fscache_write - Start a write to the cache.
|
|
* @cres: The cache resources to use
|
|
* @start_pos: The beginning file offset in the cache file
|
|
* @iter: The data to write - and also the length
|
|
* @term_func: The function to call upon completion
|
|
* @term_func_priv: The private data for @term_func
|
|
*
|
|
* Start a write to the cache. @cres indicates the cache object to write to and
|
|
* must be obtained by a call to fscache_begin_operation() beforehand.
|
|
*
|
|
* The data to be written is obtained from the iterator, @iter, and that also
|
|
* indicates the size of the operation. @start_pos is the start position in
|
|
* the file.
|
|
*
|
|
* Upon termination of the operation, @term_func will be called and supplied
|
|
* with @term_func_priv plus the amount of data written, if successful, or the
|
|
* error code otherwise.
|
|
*/
|
|
static inline
|
|
int fscache_write(struct netfs_cache_resources *cres,
|
|
loff_t start_pos,
|
|
struct iov_iter *iter,
|
|
netfs_io_terminated_t term_func,
|
|
void *term_func_priv)
|
|
{
|
|
const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
|
|
return ops->write(cres, start_pos, iter, term_func, term_func_priv);
|
|
}
|
|
|
|
/**
|
|
* fscache_clear_page_bits - Clear the PG_fscache bits from a set of pages
|
|
* @mapping: The netfs inode to use as the source
|
|
* @start: The start position in @mapping
|
|
* @len: The amount of data to unlock
|
|
* @caching: If PG_fscache has been set
|
|
*
|
|
* Clear the PG_fscache flag from a sequence of pages and wake up anyone who's
|
|
* waiting.
|
|
*/
|
|
static inline void fscache_clear_page_bits(struct address_space *mapping,
|
|
loff_t start, size_t len,
|
|
bool caching)
|
|
{
|
|
if (caching)
|
|
__fscache_clear_page_bits(mapping, start, len);
|
|
}
|
|
|
|
/**
|
|
* fscache_write_to_cache - Save a write to the cache and clear PG_fscache
|
|
* @cookie: The cookie representing the cache object
|
|
* @mapping: The netfs inode to use as the source
|
|
* @start: The start position in @mapping
|
|
* @len: The amount of data to write back
|
|
* @i_size: The new size of the inode
|
|
* @term_func: The function to call upon completion
|
|
* @term_func_priv: The private data for @term_func
|
|
* @caching: If PG_fscache has been set
|
|
*
|
|
* Helper function for a netfs to write dirty data from an inode into the cache
|
|
* object that's backing it.
|
|
*
|
|
* @start and @len describe the range of the data. This does not need to be
|
|
* page-aligned, but to satisfy DIO requirements, the cache may expand it up to
|
|
* the page boundaries on either end. All the pages covering the range must be
|
|
* marked with PG_fscache.
|
|
*
|
|
* If given, @term_func will be called upon completion and supplied with
|
|
* @term_func_priv. Note that the PG_fscache flags will have been cleared by
|
|
* this point, so the netfs must retain its own pin on the mapping.
|
|
*/
|
|
static inline void fscache_write_to_cache(struct fscache_cookie *cookie,
|
|
struct address_space *mapping,
|
|
loff_t start, size_t len, loff_t i_size,
|
|
netfs_io_terminated_t term_func,
|
|
void *term_func_priv,
|
|
bool caching)
|
|
{
|
|
if (caching)
|
|
__fscache_write_to_cache(cookie, mapping, start, len, i_size,
|
|
term_func, term_func_priv, caching);
|
|
else if (term_func)
|
|
term_func(term_func_priv, -ENOBUFS, false);
|
|
|
|
}
|
|
|
|
#if __fscache_available
|
|
bool fscache_dirty_folio(struct address_space *mapping, struct folio *folio,
|
|
struct fscache_cookie *cookie);
|
|
#else
|
|
#define fscache_dirty_folio(MAPPING, FOLIO, COOKIE) \
|
|
filemap_dirty_folio(MAPPING, FOLIO)
|
|
#endif
|
|
|
|
/**
|
|
* fscache_unpin_writeback - Unpin writeback resources
|
|
* @wbc: The writeback control
|
|
* @cookie: The cookie referring to the cache object
|
|
*
|
|
* Unpin the writeback resources pinned by fscache_dirty_folio(). This is
|
|
* intended to be called by the netfs's ->write_inode() method.
|
|
*/
|
|
static inline void fscache_unpin_writeback(struct writeback_control *wbc,
|
|
struct fscache_cookie *cookie)
|
|
{
|
|
if (wbc->unpinned_fscache_wb)
|
|
fscache_unuse_cookie(cookie, NULL, NULL);
|
|
}
|
|
|
|
/**
|
|
* fscache_clear_inode_writeback - Clear writeback resources pinned by an inode
|
|
* @cookie: The cookie referring to the cache object
|
|
* @inode: The inode to clean up
|
|
* @aux: Auxiliary data to apply to the inode
|
|
*
|
|
* Clear any writeback resources held by an inode when the inode is evicted.
|
|
* This must be called before clear_inode() is called.
|
|
*/
|
|
static inline void fscache_clear_inode_writeback(struct fscache_cookie *cookie,
|
|
struct inode *inode,
|
|
const void *aux)
|
|
{
|
|
if (inode->i_state & I_PINNING_FSCACHE_WB) {
|
|
loff_t i_size = i_size_read(inode);
|
|
fscache_unuse_cookie(cookie, aux, &i_size);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* fscache_note_page_release - Note that a netfs page got released
|
|
* @cookie: The cookie corresponding to the file
|
|
*
|
|
* Note that a page that has been copied to the cache has been released. This
|
|
* means that future reads will need to look in the cache to see if it's there.
|
|
*/
|
|
static inline
|
|
void fscache_note_page_release(struct fscache_cookie *cookie)
|
|
{
|
|
/* If we've written data to the cache (HAVE_DATA) and there wasn't any
|
|
* data in the cache when we started (NO_DATA_TO_READ), it may no
|
|
* longer be true that we can skip reading from the cache - so clear
|
|
* the flag that causes reads to be skipped.
|
|
*/
|
|
if (cookie &&
|
|
test_bit(FSCACHE_COOKIE_HAVE_DATA, &cookie->flags) &&
|
|
test_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags))
|
|
clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
|
|
}
|
|
|
|
#endif /* _LINUX_FSCACHE_H */
|