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linux/fs/cachefiles/internal.h
David Howells 5638b067d3 cachefiles: Calculate the blockshift in terms of bytes, not pages 
Cachefiles keeps track of how much space is available on the backing
filesystem and refuses new writes permission to start if there isn't enough
(we especially don't want ENOSPC happening).  It also tracks the amount of
data pending in DIO writes (cache->b_writing) and reduces the amount of
free space available by this amount before deciding if it can set up a new
write.

However, the old fscache I/O API was very much page-granularity dependent
and, as such, cachefiles's cache->bshift was meant to be a multiplier to
get from PAGE_SIZE to block size (ie. a blocksize of 512 would give a shift
of 3 for a 4KiB page) - and this was incorrectly being used to turn the
number of bytes in a DIO write into a number of blocks, leading to a
massive over estimation of the amount of data in flight.

Fix this by changing cache->bshift to be a multiplier from bytes to
blocksize and deal with quantities of blocks, not quantities of pages.

Fix also the rounding in the calculation in cachefiles_write() which needs
a "- 1" inserting.

Fixes: 047487c947 ("cachefiles: Implement the I/O routines")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164251398954.3435901.7138806620218474123.stgit@warthog.procyon.org.uk/ # v1
2022-01-21 21:36:28 +00:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* General netfs cache on cache files internal defs
*
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) "CacheFiles: " fmt
#include <linux/fscache-cache.h>
#include <linux/cred.h>
#include <linux/security.h>
#define CACHEFILES_DIO_BLOCK_SIZE 4096
struct cachefiles_cache;
struct cachefiles_object;
enum cachefiles_content {
/* These values are saved on disk */
CACHEFILES_CONTENT_NO_DATA = 0, /* No content stored */
CACHEFILES_CONTENT_SINGLE = 1, /* Content is monolithic, all is present */
CACHEFILES_CONTENT_ALL = 2, /* Content is all present, no map */
CACHEFILES_CONTENT_BACKFS_MAP = 3, /* Content is piecemeal, mapped through backing fs */
CACHEFILES_CONTENT_DIRTY = 4, /* Content is dirty (only seen on disk) */
nr__cachefiles_content
};
/*
* Cached volume representation.
*/
struct cachefiles_volume {
struct cachefiles_cache *cache;
struct list_head cache_link; /* Link in cache->volumes */
struct fscache_volume *vcookie; /* The netfs's representation */
struct dentry *dentry; /* The volume dentry */
struct dentry *fanout[256]; /* Fanout subdirs */
};
/*
* Backing file state.
*/
struct cachefiles_object {
struct fscache_cookie *cookie; /* Netfs data storage object cookie */
struct cachefiles_volume *volume; /* Cache volume that holds this object */
struct list_head cache_link; /* Link in cache->*_list */
struct file *file; /* The file representing this object */
char *d_name; /* Backing file name */
int debug_id;
spinlock_t lock;
refcount_t ref;
u8 d_name_len; /* Length of filename */
enum cachefiles_content content_info:8; /* Info about content presence */
unsigned long flags;
#define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */
};
/*
* Cache files cache definition
*/
struct cachefiles_cache {
struct fscache_cache *cache; /* Cache cookie */
struct vfsmount *mnt; /* mountpoint holding the cache */
struct dentry *store; /* Directory into which live objects go */
struct dentry *graveyard; /* directory into which dead objects go */
struct file *cachefilesd; /* manager daemon handle */
struct list_head volumes; /* List of volume objects */
struct list_head object_list; /* List of active objects */
spinlock_t object_list_lock; /* Lock for volumes and object_list */
const struct cred *cache_cred; /* security override for accessing cache */
struct mutex daemon_mutex; /* command serialisation mutex */
wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
atomic_t gravecounter; /* graveyard uniquifier */
atomic_t f_released; /* number of objects released lately */
atomic_long_t b_released; /* number of blocks released lately */
atomic_long_t b_writing; /* Number of blocks being written */
unsigned frun_percent; /* when to stop culling (% files) */
unsigned fcull_percent; /* when to start culling (% files) */
unsigned fstop_percent; /* when to stop allocating (% files) */
unsigned brun_percent; /* when to stop culling (% blocks) */
unsigned bcull_percent; /* when to start culling (% blocks) */
unsigned bstop_percent; /* when to stop allocating (% blocks) */
unsigned bsize; /* cache's block size */
unsigned bshift; /* ilog2(bsize) */
uint64_t frun; /* when to stop culling */
uint64_t fcull; /* when to start culling */
uint64_t fstop; /* when to stop allocating */
sector_t brun; /* when to stop culling */
sector_t bcull; /* when to start culling */
sector_t bstop; /* when to stop allocating */
unsigned long flags;
#define CACHEFILES_READY 0 /* T if cache prepared */
#define CACHEFILES_DEAD 1 /* T if cache dead */
#define CACHEFILES_CULLING 2 /* T if cull engaged */
#define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
char *rootdirname; /* name of cache root directory */
char *secctx; /* LSM security context */
char *tag; /* cache binding tag */
};
#include <trace/events/cachefiles.h>
static inline
struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
{
return cres->cache_priv2;
}
static inline
struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
{
return fscache_cres_cookie(cres)->cache_priv;
}
/*
* note change of state for daemon
*/
static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
{
set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
wake_up_all(&cache->daemon_pollwq);
}
/*
* cache.c
*/
extern int cachefiles_add_cache(struct cachefiles_cache *cache);
extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
enum cachefiles_has_space_for {
cachefiles_has_space_check,
cachefiles_has_space_for_write,
cachefiles_has_space_for_create,
};
extern int cachefiles_has_space(struct cachefiles_cache *cache,
unsigned fnr, unsigned bnr,
enum cachefiles_has_space_for reason);
/*
* daemon.c
*/
extern const struct file_operations cachefiles_daemon_fops;
/*
* error_inject.c
*/
#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
extern unsigned int cachefiles_error_injection_state;
extern int cachefiles_register_error_injection(void);
extern void cachefiles_unregister_error_injection(void);
#else
#define cachefiles_error_injection_state 0
static inline int cachefiles_register_error_injection(void)
{
return 0;
}
static inline void cachefiles_unregister_error_injection(void)
{
}
#endif
static inline int cachefiles_inject_read_error(void)
{
return cachefiles_error_injection_state & 2 ? -EIO : 0;
}
static inline int cachefiles_inject_write_error(void)
{
return cachefiles_error_injection_state & 2 ? -EIO :
cachefiles_error_injection_state & 1 ? -ENOSPC :
0;
}
static inline int cachefiles_inject_remove_error(void)
{
return cachefiles_error_injection_state & 2 ? -EIO : 0;
}
/*
* interface.c
*/
extern const struct fscache_cache_ops cachefiles_cache_ops;
extern void cachefiles_see_object(struct cachefiles_object *object,
enum cachefiles_obj_ref_trace why);
extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
enum cachefiles_obj_ref_trace why);
extern void cachefiles_put_object(struct cachefiles_object *object,
enum cachefiles_obj_ref_trace why);
/*
* io.c
*/
extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
enum fscache_want_state want_state);
/*
* key.c
*/
extern bool cachefiles_cook_key(struct cachefiles_object *object);
/*
* main.c
*/
extern struct kmem_cache *cachefiles_object_jar;
/*
* namei.c
*/
extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
struct file *file);
extern int cachefiles_bury_object(struct cachefiles_cache *cache,
struct cachefiles_object *object,
struct dentry *dir,
struct dentry *rep,
enum fscache_why_object_killed why);
extern int cachefiles_delete_object(struct cachefiles_object *object,
enum fscache_why_object_killed why);
extern bool cachefiles_look_up_object(struct cachefiles_object *object);
extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
struct dentry *dir,
const char *name,
bool *_is_new);
extern void cachefiles_put_directory(struct dentry *dir);
extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
char *filename);
extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
struct dentry *dir, char *filename);
extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
struct cachefiles_object *object);
/*
* security.c
*/
extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
struct dentry *root,
const struct cred **_saved_cred);
static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
const struct cred **_saved_cred)
{
*_saved_cred = override_creds(cache->cache_cred);
}
static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
const struct cred *saved_cred)
{
revert_creds(saved_cred);
}
/*
* volume.c
*/
void cachefiles_acquire_volume(struct fscache_volume *volume);
void cachefiles_free_volume(struct fscache_volume *volume);
void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
/*
* xattr.c
*/
extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
extern int cachefiles_check_auxdata(struct cachefiles_object *object,
struct file *file);
extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
struct cachefiles_object *object,
struct dentry *dentry);
extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
/*
* Error handling
*/
#define cachefiles_io_error(___cache, FMT, ...) \
do { \
pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
fscache_io_error((___cache)->cache); \
set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
} while (0)
#define cachefiles_io_error_obj(object, FMT, ...) \
do { \
struct cachefiles_cache *___cache; \
\
___cache = (object)->volume->cache; \
cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__, \
(object)->debug_id); \
} while (0)
/*
* Debug tracing
*/
extern unsigned cachefiles_debug;
#define CACHEFILES_DEBUG_KENTER 1
#define CACHEFILES_DEBUG_KLEAVE 2
#define CACHEFILES_DEBUG_KDEBUG 4
#define dbgprintk(FMT, ...) \
printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
#if defined(__KDEBUG)
#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
#elif defined(CONFIG_CACHEFILES_DEBUG)
#define _enter(FMT, ...) \
do { \
if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
kenter(FMT, ##__VA_ARGS__); \
} while (0)
#define _leave(FMT, ...) \
do { \
if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
kleave(FMT, ##__VA_ARGS__); \
} while (0)
#define _debug(FMT, ...) \
do { \
if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
kdebug(FMT, ##__VA_ARGS__); \
} while (0)
#else
#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
#endif
#if 1 /* defined(__KDEBUGALL) */
#define ASSERT(X) \
do { \
if (unlikely(!(X))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
BUG(); \
} \
} while (0)
#define ASSERTCMP(X, OP, Y) \
do { \
if (unlikely(!((X) OP (Y)))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
pr_err("%lx " #OP " %lx is false\n", \
(unsigned long)(X), (unsigned long)(Y)); \
BUG(); \
} \
} while (0)
#define ASSERTIF(C, X) \
do { \
if (unlikely((C) && !(X))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
BUG(); \
} \
} while (0)
#define ASSERTIFCMP(C, X, OP, Y) \
do { \
if (unlikely((C) && !((X) OP (Y)))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
pr_err("%lx " #OP " %lx is false\n", \
(unsigned long)(X), (unsigned long)(Y)); \
BUG(); \
} \
} while (0)
#else
#define ASSERT(X) do {} while (0)
#define ASSERTCMP(X, OP, Y) do {} while (0)
#define ASSERTIF(C, X) do {} while (0)
#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
#endif
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