FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2025-03-03 01:57:14 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

FS-Cache patches 2013-07-02

Browse Source 
-----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.13 (GNU/Linux)
 
 iQIVAwUAUdLdUxOxKuMESys7AQK1kQ//W7fgFXCG+5XVk4ECHGN5tqRn4tU69DY0
 9nYU2/y1wbqV5cTO36XTcFPQK1qbW2ZdyvEZ2CF8OfwtQpLmcALGtpBIgJwYs+4H
 DMkgO06zdk4caxc0C4JBIGs+MDeLNk2SQObqblGl1BAQKQ5cqsCLsIZ/rxln999m
 ufuobfns1YvuHkzMtswUDmm3zWMpwqqPAbbl+fTwPU683a/AleckG2ACyFvKZAxA
 OyI8kJR4e33a3/BGo/5OFb3qI1+Z25EOWdvdnM+r4hdKJZF9ZySlyc640GZHAO2J
 wKj5lYp1nBpyNPvYvly174s2MxPju1CRHb7gxcV4LX3vtEY4/MCg7m6P46EUfC6R
 C3V7PMMCjZXEQ01MKEmGig47EJKIiecCQUZupJnP7HFKPzeJR9mQZFd68WqzswAM
 w9hcCw9hQ9y/kTDVrTVCHs0Q9iTxShfrJyfRJnQ1VcoT+1dieruTa9am9OBKiEw6
 CQrPjq9RZZfsZHYr6RlGZHGJyzjrTzrf6EhxwmgaCxWycpvCuV7z76YgAVZI7V4r
 qnJmH8dXWdoSA7nZ6sgsb5TRCLT9wu1nNId0DMpAGB1cDGga/55AZtqxdoJLnlkj
 y/4wQavIrkfHHuS8c3gzVXPtYmM19CHgcKRFydXD0uGobzfxwYKTKMH+Gviu1NnH
 /pGNNY2vVGI=
 =Wjhu
 -----END PGP SIGNATURE-----

Merge tag 'fscache-20130702' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull FS-Cache updates from David Howells:
 "This contains a number of fixes for various FS-Cache issues plus some
  cleanups.  The commits are, in order:

   1) Provide a system wait_on_atomic_t() and wake_up_atomic_t() sharing
      the bit-wait table (enhancement for ).

   2) Don't put spin_lock() in a while-condition as spin_lock() may have
      a do {} while(0) wrapper (cleanup).

   3) Symbolically name i_mutex lock classes rather than using numbers
      in CacheFiles (cleanup).

   4) Don't sleep in page release if __GFP_FS is not set (deadlock vs
      ext4).

   5) Uninline fscache_object_init() (cleanup for ).

   6) Wrap checks on object state (cleanup for ).

   7) Simplify the object state machine by separating work states from
      wait states.

   8) Simplify cookie retention by objects (NULL pointer deref fix).

   9) Remove unused list_to_page() macro (cleanup).

  10) Make the remaining-pages counter in the retrieval op atomic
      (assertion failure fix).

  11) Don't use spin_is_locked() in assertions (assertion failure fix)"

* tag 'fscache-20130702' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  FS-Cache: Don't use spin_is_locked() in assertions
  FS-Cache: The retrieval remaining-pages counter needs to be atomic_t
  cachefiles: remove unused macro list_to_page()
  FS-Cache: Simplify cookie retention for fscache_objects, fixing oops
  FS-Cache: Fix object state machine to have separate work and wait states
  FS-Cache: Wrap checks on object state
  FS-Cache: Uninline fscache_object_init()
  FS-Cache: Don't sleep in page release if __GFP_FS is not set
  CacheFiles: name i_mutex lock class explicitly
  fs/fscache: remove spin_lock() from the condition in while()
  Add wait_on_atomic_t() and wake_up_atomic_t()
This commit is contained in:
Linus Torvalds 2013-07-02 09:52:47 -07:00
commit bcd7351e83
16 changed files with 966 additions and 832 deletions

13
fs/cachefiles/interface.c

@ -13,8 +13,6 @@
#include <linux/mount.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 */
@ -212,20 +210,29 @@ static void cachefiles_update_object(struct fscache_object *_object)
object = container_of(_object, struct cachefiles_object, fscache);
cache = container_of(object->fscache.cache, struct cachefiles_cache,
cache);
if (!fscache_use_cookie(_object)) {
_leave(" [relinq]");
return;
}
cookie = object->fscache.cookie;
if (!cookie->def->get_aux) {
fscache_unuse_cookie(_object);
_leave(" [no aux]");
return;
}
auxdata = kmalloc(2 + 512 + 3, cachefiles_gfp);
if (!auxdata) {
fscache_unuse_cookie(_object);
_leave(" [nomem]");
return;
}
auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
fscache_unuse_cookie(_object);
ASSERTCMP(auxlen, <, 511);
auxdata->len = auxlen + 1;
@ -263,7 +270,7 @@ static void cachefiles_drop_object(struct fscache_object *_object)
#endif
/* delete retired objects */
if (object->fscache.state == FSCACHE_OBJECT_RECYCLING &&
if (test_bit(FSCACHE_COOKIE_RETIRED, &object->fscache.cookie->flags) &&
_object != cache->cache.fsdef
) {
_debug("- retire object OBJ%x", object->fscache.debug_id);

10
fs/cachefiles/namei.c

@ -38,7 +38,7 @@ void __cachefiles_printk_object(struct cachefiles_object *object,
printk(KERN_ERR "%sobject: OBJ%x\n",
prefix, object->fscache.debug_id);
printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
prefix, fscache_object_states[object->fscache.state],
prefix, object->fscache.state->name,
object->fscache.flags, work_busy(&object->fscache.work),
object->fscache.events, object->fscache.event_mask);
printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
@ -127,10 +127,10 @@ static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
found_dentry:
kdebug("preemptive burial: OBJ%x [%s] %p",
object->fscache.debug_id,
fscache_object_states[object->fscache.state],
object->fscache.state->name,
dentry);
if (object->fscache.state < FSCACHE_OBJECT_DYING) {
if (fscache_object_is_live(&object->fscache)) {
printk(KERN_ERR "\n");
printk(KERN_ERR "CacheFiles: Error:"
" Can't preemptively bury live object\n");
@ -192,7 +192,7 @@ try_again:
/* an old object from a previous incarnation is hogging the slot - we
* need to wait for it to be destroyed */
wait_for_old_object:
if (xobject->fscache.state < FSCACHE_OBJECT_DYING) {
if (fscache_object_is_live(&object->fscache)) {
printk(KERN_ERR "\n");
printk(KERN_ERR "CacheFiles: Error:"
" Unexpected object collision\n");
@ -836,7 +836,7 @@ static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
// dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
/* look up the victim */
mutex_lock_nested(&dir->d_inode->i_mutex, 1);
mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
start = jiffies;
victim = lookup_one_len(filename, dir, strlen(filename));

6
fs/cachefiles/xattr.c

@ -109,13 +109,12 @@ int cachefiles_set_object_xattr(struct cachefiles_object *object,
struct dentry *dentry = object->dentry;
int ret;
ASSERT(object->fscache.cookie);
ASSERT(dentry);
_enter("%p,#%d", object, auxdata->len);
/* attempt to install the cache metadata directly */
_debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
_debug("SET #%u", auxdata->len);
ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
&auxdata->type, auxdata->len,
@ -138,13 +137,12 @@ int cachefiles_update_object_xattr(struct cachefiles_object *object,
struct dentry *dentry = object->dentry;
int ret;
ASSERT(object->fscache.cookie);
ASSERT(dentry);
_enter("%p,#%d", object, auxdata->len);
/* attempt to install the cache metadata directly */
_debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
_debug("SET #%u", auxdata->len);
ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
&auxdata->type, auxdata->len,

40
fs/fscache/cache.c

@ -115,7 +115,7 @@ struct fscache_cache *fscache_select_cache_for_object(
struct fscache_object, cookie_link);
cache = object->cache;
if (object->state >= FSCACHE_OBJECT_DYING ||
if (fscache_object_is_dying(object) ||
test_bit(FSCACHE_IOERROR, &cache->flags))
cache = NULL;
@ -224,8 +224,10 @@ int fscache_add_cache(struct fscache_cache *cache,
BUG_ON(!ifsdef);
cache->flags = 0;
ifsdef->event_mask = ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED);
ifsdef->state = FSCACHE_OBJECT_ACTIVE;
ifsdef->event_mask =
((1 << NR_FSCACHE_OBJECT_EVENTS) - 1) &
~(1 << FSCACHE_OBJECT_EV_CLEARED);
__set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &ifsdef->flags);
if (!tagname)
tagname = cache->identifier;
@ -330,25 +332,25 @@ static void fscache_withdraw_all_objects(struct fscache_cache *cache,
{
struct fscache_object *object;
spin_lock(&cache->object_list_lock);
while (!list_empty(&cache->object_list)) {
object = list_entry(cache->object_list.next,
struct fscache_object, cache_link);
list_move_tail(&object->cache_link, dying_objects);
_debug("withdraw %p", object->cookie);
spin_lock(&object->lock);
spin_unlock(&cache->object_list_lock);
fscache_raise_event(object, FSCACHE_OBJECT_EV_WITHDRAW);
spin_unlock(&object->lock);
cond_resched();
spin_lock(&cache->object_list_lock);
}
spin_unlock(&cache->object_list_lock);
if (!list_empty(&cache->object_list)) {
object = list_entry(cache->object_list.next,
struct fscache_object, cache_link);
list_move_tail(&object->cache_link, dying_objects);
_debug("withdraw %p", object->cookie);
/* This must be done under object_list_lock to prevent
* a race with fscache_drop_object().
*/
fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL);
}
spin_unlock(&cache->object_list_lock);
cond_resched();
}
}
/**

93
fs/fscache/cookie.c

@ -95,6 +95,11 @@ struct fscache_cookie *__fscache_acquire_cookie(
atomic_set(&cookie->usage, 1);
atomic_set(&cookie->n_children, 0);
/* We keep the active count elevated until relinquishment to prevent an
* attempt to wake up every time the object operations queue quiesces.
*/
atomic_set(&cookie->n_active, 1);
atomic_inc(&parent->usage);
atomic_inc(&parent->n_children);
@ -177,7 +182,6 @@ static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie)
cookie->flags =
(1 << FSCACHE_COOKIE_LOOKING_UP) |
(1 << FSCACHE_COOKIE_CREATING) |
(1 << FSCACHE_COOKIE_NO_DATA_YET);
/* ask the cache to allocate objects for this cookie and its parent
@ -205,7 +209,7 @@ static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie)
/* initiate the process of looking up all the objects in the chain
* (done by fscache_initialise_object()) */
fscache_enqueue_object(object);
fscache_raise_event(object, FSCACHE_OBJECT_EV_NEW_CHILD);
spin_unlock(&cookie->lock);
@ -285,7 +289,7 @@ static int fscache_alloc_object(struct fscache_cache *cache,
object_already_extant:
ret = -ENOBUFS;
if (object->state >= FSCACHE_OBJECT_DYING) {
if (fscache_object_is_dead(object)) {
spin_unlock(&cookie->lock);
goto error;
}
@ -321,7 +325,7 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
ret = -EEXIST;
hlist_for_each_entry(p, &cookie->backing_objects, cookie_link) {
if (p->cache == object->cache) {
if (p->state >= FSCACHE_OBJECT_DYING)
if (fscache_object_is_dying(p))
ret = -ENOBUFS;
goto cant_attach_object;
}
@ -332,7 +336,7 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
hlist_for_each_entry(p, &cookie->parent->backing_objects,
cookie_link) {
if (p->cache == object->cache) {
if (p->state >= FSCACHE_OBJECT_DYING) {
if (fscache_object_is_dying(p)) {
ret = -ENOBUFS;
spin_unlock(&cookie->parent->lock);
goto cant_attach_object;
@ -400,7 +404,7 @@ void __fscache_invalidate(struct fscache_cookie *cookie)
object = hlist_entry(cookie->backing_objects.first,
struct fscache_object,
cookie_link);
if (object->state < FSCACHE_OBJECT_DYING)
if (fscache_object_is_live(object))
fscache_raise_event(
object, FSCACHE_OBJECT_EV_INVALIDATE);
}
@ -467,9 +471,7 @@ EXPORT_SYMBOL(__fscache_update_cookie);
*/
void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
{
struct fscache_cache *cache;
struct fscache_object *object;
unsigned long event;
fscache_stat(&fscache_n_relinquishes);
if (retire)
@ -481,8 +483,11 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
return;
}
_enter("%p{%s,%p},%d",
cookie, cookie->def->name, cookie->netfs_data, retire);
_enter("%p{%s,%p,%d},%d",
cookie, cookie->def->name, cookie->netfs_data,
atomic_read(&cookie->n_active), retire);
ASSERTCMP(atomic_read(&cookie->n_active), >, 0);
if (atomic_read(&cookie->n_children) != 0) {
printk(KERN_ERR "FS-Cache: Cookie '%s' still has children\n",
@ -490,62 +495,28 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
BUG();
}
/* wait for the cookie to finish being instantiated (or to fail) */
if (test_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) {
fscache_stat(&fscache_n_relinquishes_waitcrt);
wait_on_bit(&cookie->flags, FSCACHE_COOKIE_CREATING,
fscache_wait_bit, TASK_UNINTERRUPTIBLE);
}
/* No further netfs-accessing operations on this cookie permitted */
set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags);
if (retire)
set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags);
event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE;
try_again:
spin_lock(&cookie->lock);
/* break links with all the active objects */
while (!hlist_empty(&cookie->backing_objects)) {
int n_reads;
object = hlist_entry(cookie->backing_objects.first,
struct fscache_object,
cookie_link);
_debug("RELEASE OBJ%x", object->debug_id);
set_bit(FSCACHE_COOKIE_WAITING_ON_READS, &cookie->flags);
n_reads = atomic_read(&object->n_reads);
if (n_reads) {
int n_ops = object->n_ops;
int n_in_progress = object->n_in_progress;
spin_unlock(&cookie->lock);
printk(KERN_ERR "FS-Cache:"
" Cookie '%s' still has %d outstanding reads (%d,%d)\n",
cookie->def->name,
n_reads, n_ops, n_in_progress);
wait_on_bit(&cookie->flags, FSCACHE_COOKIE_WAITING_ON_READS,
fscache_wait_bit, TASK_UNINTERRUPTIBLE);
printk("Wait finished\n");
goto try_again;
}
/* detach each cache object from the object cookie */
spin_lock(&object->lock);
hlist_del_init(&object->cookie_link);
cache = object->cache;
object->cookie = NULL;
fscache_raise_event(object, event);
spin_unlock(&object->lock);
if (atomic_dec_and_test(&cookie->usage))
/* the cookie refcount shouldn't be reduced to 0 yet */
BUG();
hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) {
fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL);
}
spin_unlock(&cookie->lock);
/* detach pointers back to the netfs */
/* Wait for cessation of activity requiring access to the netfs (when
* n_active reaches 0).
*/
if (!atomic_dec_and_test(&cookie->n_active))
wait_on_atomic_t(&cookie->n_active, fscache_wait_atomic_t,
TASK_UNINTERRUPTIBLE);
/* Clear pointers back to the netfs */
cookie->netfs_data = NULL;
cookie->def = NULL;
spin_unlock(&cookie->lock);
BUG_ON(cookie->stores.rnode);
if (cookie->parent) {
ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
@ -553,7 +524,7 @@ try_again:
atomic_dec(&cookie->parent->n_children);
}
/* finally dispose of the cookie */
/* Dispose of the netfs's link to the cookie */
ASSERTCMP(atomic_read(&cookie->usage), >, 0);
fscache_cookie_put(cookie);

1
fs/fscache/fsdef.c

@ -55,6 +55,7 @@ static struct fscache_cookie_def fscache_fsdef_index_def = {
struct fscache_cookie fscache_fsdef_index = {
.usage = ATOMIC_INIT(1),
.n_active = ATOMIC_INIT(1),
.lock = __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock),
.backing_objects = HLIST_HEAD_INIT,
.def = &fscache_fsdef_index_def,

11
fs/fscache/internal.h

@ -93,14 +93,11 @@ static inline bool fscache_object_congested(void)
extern int fscache_wait_bit(void *);
extern int fscache_wait_bit_interruptible(void *);
extern int fscache_wait_atomic_t(atomic_t *);
/*
* object.c
*/
extern const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5];
extern void fscache_withdrawing_object(struct fscache_cache *,
struct fscache_object *);
extern void fscache_enqueue_object(struct fscache_object *);
/*
@ -110,8 +107,10 @@ extern void fscache_enqueue_object(struct fscache_object *);
extern const struct file_operations fscache_objlist_fops;
extern void fscache_objlist_add(struct fscache_object *);
extern void fscache_objlist_remove(struct fscache_object *);
#else
#define fscache_objlist_add(object) do {} while(0)
#define fscache_objlist_remove(object) do {} while(0)
#endif
/*
@ -291,6 +290,10 @@ static inline void fscache_raise_event(struct fscache_object *object,
unsigned event)
{
BUG_ON(event >= NR_FSCACHE_OBJECT_EVENTS);
#if 0
printk("*** fscache_raise_event(OBJ%d{%lx},%x)\n",
object->debug_id, object->event_mask, (1 << event));
#endif
if (!test_and_set_bit(event, &object->events) &&
test_bit(event, &object->event_mask))
fscache_enqueue_object(object);

11
fs/fscache/main.c

@ -205,7 +205,6 @@ int fscache_wait_bit(void *flags)
schedule();
return 0;
}
EXPORT_SYMBOL(fscache_wait_bit);
/*
* wait_on_bit() sleep function for interruptible waiting
@ -215,4 +214,12 @@ int fscache_wait_bit_interruptible(void *flags)
schedule();
return signal_pending(current);
}
EXPORT_SYMBOL(fscache_wait_bit_interruptible);
/*
* wait_on_atomic_t() sleep function for uninterruptible waiting
*/
int fscache_wait_atomic_t(atomic_t *p)
{
schedule();
return 0;
}

1
fs/fscache/netfs.c

@ -40,6 +40,7 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
/* initialise the primary index cookie */
atomic_set(&netfs->primary_index->usage, 1);
atomic_set(&netfs->primary_index->n_children, 0);
atomic_set(&netfs->primary_index->n_active, 1);
netfs->primary_index->def = &fscache_fsdef_netfs_def;
netfs->primary_index->parent = &fscache_fsdef_index;

103
fs/fscache/object-list.c

@ -70,13 +70,10 @@ void fscache_objlist_add(struct fscache_object *obj)
write_unlock(&fscache_object_list_lock);
}
/**
* fscache_object_destroy - Note that a cache object is about to be destroyed
* @object: The object to be destroyed
*
* Note the imminent destruction and deallocation of a cache object record.
/*
* Remove an object from the object list.
*/
void fscache_object_destroy(struct fscache_object *obj)
void fscache_objlist_remove(struct fscache_object *obj)
{
write_lock(&fscache_object_list_lock);
@ -85,7 +82,6 @@ void fscache_object_destroy(struct fscache_object *obj)
write_unlock(&fscache_object_list_lock);
}
EXPORT_SYMBOL(fscache_object_destroy);
/*
* find the object in the tree on or after the specified index
@ -166,15 +162,14 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
{
struct fscache_objlist_data *data = m->private;
struct fscache_object *obj = v;
struct fscache_cookie *cookie;
unsigned long config = data->config;
uint16_t keylen, auxlen;
char _type[3], *type;
bool no_cookie;
u8 *buf = data->buf, *p;
if ((unsigned long) v == 1) {
seq_puts(m, "OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS"
" EM EV F S"
" EM EV FL S"
" | NETFS_COOKIE_DEF TY FL NETFS_DATA");
if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
FSCACHE_OBJLIST_CONFIG_AUX))
@ -193,7 +188,7 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
if ((unsigned long) v == 2) {
seq_puts(m, "======== ======== ==== ===== === === === == ====="
" == == = ="
" == == == ="
" | ================ == == ================");
if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
FSCACHE_OBJLIST_CONFIG_AUX))
@ -216,10 +211,11 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
} \
} while(0)
cookie = obj->cookie;
if (~config) {
FILTER(obj->cookie,
FILTER(cookie->def,
COOKIE, NOCOOKIE);
FILTER(obj->state != FSCACHE_OBJECT_ACTIVE ||
FILTER(fscache_object_is_active(obj) ||
obj->n_ops != 0 ||
obj->n_obj_ops != 0 ||
obj->flags ||
@ -235,10 +231,10 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
}
seq_printf(m,
"%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1x | ",
"%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
obj->debug_id,
obj->parent ? obj->parent->debug_id : -1,
fscache_object_states_short[obj->state],
obj->state->short_name,
obj->n_children,
obj->n_ops,
obj->n_obj_ops,
@ -250,48 +246,40 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
obj->flags,
work_busy(&obj->work));
no_cookie = true;
keylen = auxlen = 0;
if (obj->cookie) {
spin_lock(&obj->lock);
if (obj->cookie) {
switch (obj->cookie->def->type) {
case 0:
type = "IX";
break;
case 1:
type = "DT";
break;
default:
sprintf(_type, "%02u",
obj->cookie->def->type);
type = _type;
break;
}
if (fscache_use_cookie(obj)) {
uint16_t keylen = 0, auxlen = 0;
seq_printf(m, "%-16s %s %2lx %16p",
obj->cookie->def->name,
type,
obj->cookie->flags,
obj->cookie->netfs_data);
if (obj->cookie->def->get_key &&
config & FSCACHE_OBJLIST_CONFIG_KEY)
keylen = obj->cookie->def->get_key(
obj->cookie->netfs_data,
buf, 400);
if (obj->cookie->def->get_aux &&
config & FSCACHE_OBJLIST_CONFIG_AUX)
auxlen = obj->cookie->def->get_aux(
obj->cookie->netfs_data,
buf + keylen, 512 - keylen);
no_cookie = false;
switch (cookie->def->type) {
case 0:
type = "IX";
break;
case 1:
type = "DT";
break;
default:
sprintf(_type, "%02u", cookie->def->type);
type = _type;
break;
}
spin_unlock(&obj->lock);
if (!no_cookie && (keylen > 0 || auxlen > 0)) {
seq_printf(m, "%-16s %s %2lx %16p",
cookie->def->name,
type,
cookie->flags,
cookie->netfs_data);
if (cookie->def->get_key &&
config & FSCACHE_OBJLIST_CONFIG_KEY)
keylen = cookie->def->get_key(cookie->netfs_data,
buf, 400);
if (cookie->def->get_aux &&
config & FSCACHE_OBJLIST_CONFIG_AUX)
auxlen = cookie->def->get_aux(cookie->netfs_data,
buf + keylen, 512 - keylen);
fscache_unuse_cookie(obj);
if (keylen > 0 || auxlen > 0) {
seq_printf(m, " ");
for (p = buf; keylen > 0; keylen--)
seq_printf(m, "%02x", *p++);
@ -302,12 +290,11 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
seq_printf(m, "%02x", *p++);
}
}
}
if (no_cookie)
seq_printf(m, "<no_cookie>\n");
else
seq_printf(m, "\n");
} else {
seq_printf(m, "<no_netfs>\n");
}
return 0;
}

1112
fs/fscache/object.c

File diff suppressed because it is too large Load Diff

37
fs/fscache/operation.c

@ -35,7 +35,7 @@ void fscache_enqueue_operation(struct fscache_operation *op)
ASSERT(list_empty(&op->pend_link));
ASSERT(op->processor != NULL);
ASSERTCMP(op->object->state, >=, FSCACHE_OBJECT_AVAILABLE);
ASSERT(fscache_object_is_available(op->object));
ASSERTCMP(atomic_read(&op->usage), >, 0);
ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
@ -119,7 +119,7 @@ int fscache_submit_exclusive_op(struct fscache_object *object,
/* need to issue a new write op after this */
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
ret = 0;
} else if (object->state == FSCACHE_OBJECT_CREATING) {
} else if (test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
op->object = object;
object->n_ops++;
object->n_exclusive++; /* reads and writes must wait */
@ -144,7 +144,7 @@ int fscache_submit_exclusive_op(struct fscache_object *object,
*/
static void fscache_report_unexpected_submission(struct fscache_object *object,
struct fscache_operation *op,
unsigned long ostate)
const struct fscache_state *ostate)
{
static bool once_only;
struct fscache_operation *p;
@ -155,11 +155,8 @@ static void fscache_report_unexpected_submission(struct fscache_object *object,
once_only = true;
kdebug("unexpected submission OP%x [OBJ%x %s]",
op->debug_id, object->debug_id,
fscache_object_states[object->state]);
kdebug("objstate=%s [%s]",
fscache_object_states[object->state],
fscache_object_states[ostate]);
op->debug_id, object->debug_id, object->state->name);
kdebug("objstate=%s [%s]", object->state->name, ostate->name);
kdebug("objflags=%lx", object->flags);
kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
kdebug("ops=%u inp=%u exc=%u",
@ -190,7 +187,7 @@ static void fscache_report_unexpected_submission(struct fscache_object *object,
int fscache_submit_op(struct fscache_object *object,
struct fscache_operation *op)
{
unsigned long ostate;
const struct fscache_state *ostate;
int ret;
_enter("{OBJ%x OP%x},{%u}",
@ -226,16 +223,14 @@ int fscache_submit_op(struct fscache_object *object,
fscache_run_op(object, op);
}
ret = 0;
} else if (object->state == FSCACHE_OBJECT_CREATING) {
} else if (test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
op->object = object;
object->n_ops++;
atomic_inc(&op->usage);
list_add_tail(&op->pend_link, &object->pending_ops);
fscache_stat(&fscache_n_op_pend);
ret = 0;
} else if (object->state == FSCACHE_OBJECT_DYING ||
object->state == FSCACHE_OBJECT_LC_DYING ||
object->state == FSCACHE_OBJECT_WITHDRAWING) {
} else if (fscache_object_is_dying(object)) {
fscache_stat(&fscache_n_op_rejected);
op->state = FSCACHE_OP_ST_CANCELLED;
ret = -ENOBUFS;
@ -265,8 +260,8 @@ void fscache_abort_object(struct fscache_object *object)
}
/*
* jump start the operation processing on an object
* - caller must hold object->lock
* Jump start the operation processing on an object. The caller must hold
* object->lock.
*/
void fscache_start_operations(struct fscache_object *object)
{
@ -428,14 +423,10 @@ void fscache_put_operation(struct fscache_operation *op)
object = op->object;
if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags)) {
if (atomic_dec_and_test(&object->n_reads)) {
clear_bit(FSCACHE_COOKIE_WAITING_ON_READS,
&object->cookie->flags);
wake_up_bit(&object->cookie->flags,
FSCACHE_COOKIE_WAITING_ON_READS);
}
}
if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
atomic_dec(&object->n_reads);
if (test_bit(FSCACHE_OP_UNUSE_COOKIE, &op->flags))
fscache_unuse_cookie(object);
/* now... we may get called with the object spinlock held, so we
* complete the cleanup here only if we can immediately acquire the

65
fs/fscache/page.c

@ -109,7 +109,7 @@ page_busy:
* allocator as the work threads writing to the cache may all end up
* sleeping on memory allocation, so we may need to impose a timeout
* too. */
if (!(gfp & __GFP_WAIT)) {
if (!(gfp & __GFP_WAIT) || !(gfp & __GFP_FS)) {
fscache_stat(&fscache_n_store_vmscan_busy);
return false;
}
@ -163,10 +163,12 @@ static void fscache_attr_changed_op(struct fscache_operation *op)
fscache_stat(&fscache_n_attr_changed_calls);
if (fscache_object_is_active(object)) {
if (fscache_object_is_active(object) &&
fscache_use_cookie(object)) {
fscache_stat(&fscache_n_cop_attr_changed);
ret = object->cache->ops->attr_changed(object);
fscache_stat_d(&fscache_n_cop_attr_changed);
fscache_unuse_cookie(object);
if (ret < 0)
fscache_abort_object(object);
}
@ -233,7 +235,7 @@ static void fscache_release_retrieval_op(struct fscache_operation *_op)
_enter("{OP%x}", op->op.debug_id);
ASSERTCMP(op->n_pages, ==, 0);
ASSERTCMP(atomic_read(&op->n_pages), ==, 0);
fscache_hist(fscache_retrieval_histogram, op->start_time);
if (op->context)
@ -246,6 +248,7 @@ static void fscache_release_retrieval_op(struct fscache_operation *_op)
* allocate a retrieval op
*/
static struct fscache_retrieval *fscache_alloc_retrieval(
struct fscache_cookie *cookie,
struct address_space *mapping,
fscache_rw_complete_t end_io_func,
void *context)
@ -260,7 +263,10 @@ static struct fscache_retrieval *fscache_alloc_retrieval(
}
fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op);
op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
atomic_inc(&cookie->n_active);
op->op.flags = FSCACHE_OP_MYTHREAD |
(1UL << FSCACHE_OP_WAITING) |
(1UL << FSCACHE_OP_UNUSE_COOKIE);
op->mapping = mapping;
op->end_io_func = end_io_func;
op->context = context;
@ -310,7 +316,7 @@ static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
struct fscache_retrieval *op =
container_of(_op, struct fscache_retrieval, op);
op->n_pages = 0;
atomic_set(&op->n_pages, 0);
}
/*
@ -394,12 +400,13 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
if (fscache_wait_for_deferred_lookup(cookie) < 0)
return -ERESTARTSYS;
op = fscache_alloc_retrieval(page->mapping, end_io_func, context);
op = fscache_alloc_retrieval(cookie, page->mapping,
end_io_func,context);
if (!op) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
op->n_pages = 1;
atomic_set(&op->n_pages, 1);
spin_lock(&cookie->lock);
@ -408,7 +415,7 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
object = hlist_entry(cookie->backing_objects.first,
struct fscache_object, cookie_link);
ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
ASSERT(test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags));
atomic_inc(&object->n_reads);
__set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
@ -465,6 +472,7 @@ nobufs_unlock_dec:
atomic_dec(&object->n_reads);
nobufs_unlock:
spin_unlock(&cookie->lock);
atomic_dec(&cookie->n_active);
kfree(op);
nobufs:
fscache_stat(&fscache_n_retrievals_nobufs);
@ -522,10 +530,10 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
if (fscache_wait_for_deferred_lookup(cookie) < 0)
return -ERESTARTSYS;
op = fscache_alloc_retrieval(mapping, end_io_func, context);
op = fscache_alloc_retrieval(cookie, mapping, end_io_func, context);
if (!op)
return -ENOMEM;
op->n_pages = *nr_pages;
atomic_set(&op->n_pages, *nr_pages);
spin_lock(&cookie->lock);
@ -589,6 +597,7 @@ nobufs_unlock_dec:
atomic_dec(&object->n_reads);
nobufs_unlock:
spin_unlock(&cookie->lock);
atomic_dec(&cookie->n_active);
kfree(op);
nobufs:
fscache_stat(&fscache_n_retrievals_nobufs);
@ -631,10 +640,10 @@ int __fscache_alloc_page(struct fscache_cookie *cookie,
if (fscache_wait_for_deferred_lookup(cookie) < 0)
return -ERESTARTSYS;
op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
op = fscache_alloc_retrieval(cookie, page->mapping, NULL, NULL);
if (!op)
return -ENOMEM;
op->n_pages = 1;
atomic_set(&op->n_pages, 1);
spin_lock(&cookie->lock);
@ -675,6 +684,7 @@ error:
nobufs_unlock:
spin_unlock(&cookie->lock);
atomic_dec(&cookie->n_active);
kfree(op);
nobufs:
fscache_stat(&fscache_n_allocs_nobufs);
@ -729,8 +739,9 @@ static void fscache_write_op(struct fscache_operation *_op)
*/
spin_unlock(&object->lock);
fscache_op_complete(&op->op, false);
_leave(" [cancel] op{f=%lx s=%u} obj{s=%u f=%lx}",
_op->flags, _op->state, object->state, object->flags);
_leave(" [cancel] op{f=%lx s=%u} obj{s=%s f=%lx}",
_op->flags, _op->state, object->state->short_name,
object->flags);
return;
}
@ -796,11 +807,16 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie)
_enter("");
while (spin_lock(&cookie->stores_lock),
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
ARRAY_SIZE(results),
FSCACHE_COOKIE_PENDING_TAG),
n > 0) {
for (;;) {
spin_lock(&cookie->stores_lock);
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
ARRAY_SIZE(results),
FSCACHE_COOKIE_PENDING_TAG);
if (n == 0) {
spin_unlock(&cookie->stores_lock);
break;
}
for (i = n - 1; i >= 0; i--) {
page = results[i];
radix_tree_delete(&cookie->stores, page->index);
@ -812,7 +828,6 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie)
page_cache_release(results[i]);
}
spin_unlock(&cookie->stores_lock);
_leave("");
}
@ -829,14 +844,12 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie)
* (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
* set)
*
* (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred
* fill op)
* (a) no writes yet
*
* (b) writes deferred till post-creation (mark page for writing and
* return immediately)
*
* (2) negative lookup, object created, initial fill being made from netfs
* (FSCACHE_COOKIE_INITIAL_FILL is set)
*
* (a) fill point not yet reached this page (mark page for writing and
* return)
@ -873,7 +886,9 @@ int __fscache_write_page(struct fscache_cookie *cookie,
fscache_operation_init(&op->op, fscache_write_op,
fscache_release_write_op);
op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING);
op->op.flags = FSCACHE_OP_ASYNC |
(1 << FSCACHE_OP_WAITING) |
(1 << FSCACHE_OP_UNUSE_COOKIE);
ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
if (ret < 0)
@ -919,6 +934,7 @@ int __fscache_write_page(struct fscache_cookie *cookie,
op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
op->store_limit = object->store_limit;
atomic_inc(&cookie->n_active);
if (fscache_submit_op(object, &op->op) < 0)
goto submit_failed;
@ -945,6 +961,7 @@ already_pending:
return 0;
submit_failed:
atomic_dec(&cookie->n_active);
spin_lock(&cookie->stores_lock);
radix_tree_delete(&cookie->stores, page->index);
spin_unlock(&cookie->stores_lock);

183
include/linux/fscache-cache.h

@ -97,7 +97,8 @@ struct fscache_operation {
#define FSCACHE_OP_WAITING 4 /* cleared when op is woken */
#define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */
#define FSCACHE_OP_DEC_READ_CNT 6 /* decrement object->n_reads on destruction */
#define FSCACHE_OP_KEEP_FLAGS 0x0070 /* flags to keep when repurposing an op */
#define FSCACHE_OP_UNUSE_COOKIE 7 /* call fscache_unuse_cookie() on completion */
#define FSCACHE_OP_KEEP_FLAGS 0x00f0 /* flags to keep when repurposing an op */
enum fscache_operation_state state;
atomic_t usage;
@ -150,7 +151,7 @@ struct fscache_retrieval {
void *context; /* netfs read context (pinned) */
struct list_head to_do; /* list of things to be done by the backend */
unsigned long start_time; /* time at which retrieval started */
unsigned n_pages; /* number of pages to be retrieved */
atomic_t n_pages; /* number of pages to be retrieved */
};
typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op,
@ -194,15 +195,14 @@ static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op)
static inline void fscache_retrieval_complete(struct fscache_retrieval *op,
int n_pages)
{
op->n_pages -= n_pages;
if (op->n_pages <= 0)
atomic_sub(n_pages, &op->n_pages);
if (atomic_read(&op->n_pages) <= 0)
fscache_op_complete(&op->op, true);
}
/**
* fscache_put_retrieval - Drop a reference to a retrieval operation
* @op: The retrieval operation affected
* @n_pages: The number of pages to account for
*
* Drop a reference to a retrieval operation.
*/
@ -314,6 +314,7 @@ struct fscache_cache_ops {
struct fscache_cookie {
atomic_t usage; /* number of users of this cookie */
atomic_t n_children; /* number of children of this cookie */
atomic_t n_active; /* number of active users of netfs ptrs */
spinlock_t lock;
spinlock_t stores_lock; /* lock on page store tree */
struct hlist_head backing_objects; /* object(s) backing this file/index */
@ -326,13 +327,11 @@ struct fscache_cookie {
unsigned long flags;
#define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */
#define FSCACHE_COOKIE_CREATING 1 /* T if non-index object being created still */
#define FSCACHE_COOKIE_NO_DATA_YET 2 /* T if new object with no cached data yet */
#define FSCACHE_COOKIE_PENDING_FILL 3 /* T if pending initial fill on object */
#define FSCACHE_COOKIE_FILLING 4 /* T if filling object incrementally */
#define FSCACHE_COOKIE_UNAVAILABLE 5 /* T if cookie is unavailable (error, etc) */
#define FSCACHE_COOKIE_WAITING_ON_READS 6 /* T if cookie is waiting on reads */
#define FSCACHE_COOKIE_INVALIDATING 7 /* T if cookie is being invalidated */
#define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */
#define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */
#define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */
#define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */
#define FSCACHE_COOKIE_RETIRED 5 /* T if cookie was retired */
};
extern struct fscache_cookie fscache_fsdef_index;
@ -341,45 +340,40 @@ extern struct fscache_cookie fscache_fsdef_index;
* Event list for fscache_object::{event_mask,events}
*/
enum {
FSCACHE_OBJECT_EV_REQUEUE, /* T if object should be requeued */
FSCACHE_OBJECT_EV_NEW_CHILD, /* T if object has a new child */
FSCACHE_OBJECT_EV_PARENT_READY, /* T if object's parent is ready */
FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */
FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */
FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */
FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */
FSCACHE_OBJECT_EV_RELEASE, /* T if netfs requested object release */
FSCACHE_OBJECT_EV_RETIRE, /* T if netfs requested object retirement */
FSCACHE_OBJECT_EV_WITHDRAW, /* T if cache requested object withdrawal */
FSCACHE_OBJECT_EV_KILL, /* T if netfs relinquished or cache withdrew object */
NR_FSCACHE_OBJECT_EVENTS
};
#define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1)
/*
* States for object state machine.
*/
struct fscache_transition {
unsigned long events;
const struct fscache_state *transit_to;
};
struct fscache_state {
char name[24];
char short_name[8];
const struct fscache_state *(*work)(struct fscache_object *object,
int event);
const struct fscache_transition transitions[];
};
/*
* on-disk cache file or index handle
*/
struct fscache_object {
enum fscache_object_state {
FSCACHE_OBJECT_INIT, /* object in initial unbound state */
FSCACHE_OBJECT_LOOKING_UP, /* looking up object */
FSCACHE_OBJECT_CREATING, /* creating object */
/* active states */
FSCACHE_OBJECT_AVAILABLE, /* cleaning up object after creation */
FSCACHE_OBJECT_ACTIVE, /* object is usable */
FSCACHE_OBJECT_INVALIDATING, /* object is invalidating */
FSCACHE_OBJECT_UPDATING, /* object is updating */
/* terminal states */
FSCACHE_OBJECT_DYING, /* object waiting for accessors to finish */
FSCACHE_OBJECT_LC_DYING, /* object cleaning up after lookup/create */
FSCACHE_OBJECT_ABORT_INIT, /* abort the init state */
FSCACHE_OBJECT_RELEASING, /* releasing object */
FSCACHE_OBJECT_RECYCLING, /* retiring object */
FSCACHE_OBJECT_WITHDRAWING, /* withdrawing object */
FSCACHE_OBJECT_DEAD, /* object is now dead */
FSCACHE_OBJECT__NSTATES
} state;
const struct fscache_state *state; /* Object state machine state */
const struct fscache_transition *oob_table; /* OOB state transition table */
int debug_id; /* debugging ID */
int n_children; /* number of child objects */
int n_ops; /* number of extant ops on object */
@ -390,6 +384,7 @@ struct fscache_object {
spinlock_t lock; /* state and operations lock */
unsigned long lookup_jif; /* time at which lookup started */
unsigned long oob_event_mask; /* OOB events this object is interested in */
unsigned long event_mask; /* events this object is interested in */
unsigned long events; /* events to be processed by this object
* (order is important - using fls) */
@ -398,6 +393,9 @@ struct fscache_object {
#define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */
#define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */
#define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */
#define FSCACHE_OBJECT_IS_LIVE 3 /* T if object is not withdrawn or relinquished */
#define FSCACHE_OBJECT_IS_LOOKED_UP 4 /* T if object has been looked up */
#define FSCACHE_OBJECT_IS_AVAILABLE 5 /* T if object has become active */
struct list_head cache_link; /* link in cache->object_list */
struct hlist_node cookie_link; /* link in cookie->backing_objects */
@ -415,62 +413,40 @@ struct fscache_object {
loff_t store_limit_l; /* current storage limit */
};
extern const char *fscache_object_states[];
#define fscache_object_is_active(obj) \
(!test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
(obj)->state >= FSCACHE_OBJECT_AVAILABLE && \
(obj)->state < FSCACHE_OBJECT_DYING)
#define fscache_object_is_dead(obj) \
(test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
(obj)->state >= FSCACHE_OBJECT_DYING)
extern void fscache_object_work_func(struct work_struct *work);
/**
* fscache_object_init - Initialise a cache object description
* @object: Object description
*
* Initialise a cache object description to its basic values.
*
* See Documentation/filesystems/caching/backend-api.txt for a complete
* description.
*/
static inline
void fscache_object_init(struct fscache_object *object,
struct fscache_cookie *cookie,
struct fscache_cache *cache)
{
atomic_inc(&cache->object_count);
object->state = FSCACHE_OBJECT_INIT;
spin_lock_init(&object->lock);
INIT_LIST_HEAD(&object->cache_link);
INIT_HLIST_NODE(&object->cookie_link);
INIT_WORK(&object->work, fscache_object_work_func);
INIT_LIST_HEAD(&object->dependents);
INIT_LIST_HEAD(&object->dep_link);
INIT_LIST_HEAD(&object->pending_ops);
object->n_children = 0;
object->n_ops = object->n_in_progress = object->n_exclusive = 0;
object->events = object->event_mask = 0;
object->flags = 0;
object->store_limit = 0;
object->store_limit_l = 0;
object->cache = cache;
object->cookie = cookie;
object->parent = NULL;
}
extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *,
struct fscache_cache *);
extern void fscache_object_destroy(struct fscache_object *);
extern void fscache_object_lookup_negative(struct fscache_object *object);
extern void fscache_obtained_object(struct fscache_object *object);
#ifdef CONFIG_FSCACHE_OBJECT_LIST
extern void fscache_object_destroy(struct fscache_object *object);
#else
#define fscache_object_destroy(object) do {} while(0)
#endif
static inline bool fscache_object_is_live(struct fscache_object *object)
{
return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
}
static inline bool fscache_object_is_dying(struct fscache_object *object)
{
return !fscache_object_is_live(object);
}
static inline bool fscache_object_is_available(struct fscache_object *object)
{
return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
}
static inline bool fscache_object_is_active(struct fscache_object *object)
{
return fscache_object_is_available(object) &&
fscache_object_is_live(object) &&
!test_bit(FSCACHE_IOERROR, &object->cache->flags);
}
static inline bool fscache_object_is_dead(struct fscache_object *object)
{
return fscache_object_is_dying(object) &&
test_bit(FSCACHE_IOERROR, &object->cache->flags);
}
/**
* fscache_object_destroyed - Note destruction of an object in a cache
@ -531,6 +507,33 @@ static inline void fscache_end_io(struct fscache_retrieval *op,
op->end_io_func(page, op->context, error);
}
/**
* fscache_use_cookie - Request usage of cookie attached to an object
* @object: Object description
*
* Request usage of the cookie attached to an object. NULL is returned if the
* relinquishment had reduced the cookie usage count to 0.
*/
static inline bool fscache_use_cookie(struct fscache_object *object)
{
struct fscache_cookie *cookie = object->cookie;
return atomic_inc_not_zero(&cookie->n_active) != 0;
}
/**
* fscache_unuse_cookie - Cease usage of cookie attached to an object
* @object: Object description
*
* 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_object *object)
{
struct fscache_cookie *cookie = object->cookie;
if (atomic_dec_and_test(&cookie->n_active))
wake_up_atomic_t(&cookie->n_active);
}
/*
* out-of-line cache backend functions
*/

24
include/linux/wait.h

@ -23,6 +23,7 @@ struct __wait_queue {
struct wait_bit_key {
void *flags;
int bit_nr;
#define WAIT_ATOMIC_T_BIT_NR -1
};
struct wait_bit_queue {
@ -60,6 +61,9 @@ struct task_struct;
#define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
{ .flags = word, .bit_nr = bit, }
#define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \
{ .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
#define init_waitqueue_head(q) \
@ -146,8 +150,10 @@ void __wake_up_bit(wait_queue_head_t *, void *, int);
int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
void wake_up_bit(void *, int);
void wake_up_atomic_t(atomic_t *);
int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
wait_queue_head_t *bit_waitqueue(void *, int);
#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
@ -902,5 +908,23 @@ static inline int wait_on_bit_lock(void *word, int bit,
return 0;
return out_of_line_wait_on_bit_lock(word, bit, action, mode);
}
/**
* wait_on_atomic_t - Wait for an atomic_t to become 0
* @val: The atomic value being waited on, a kernel virtual address
* @action: the function used to sleep, which may take special actions
* @mode: the task state to sleep in
*
* Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for
* the purpose of getting a waitqueue, but we set the key to a bit number
* outside of the target 'word'.
*/
static inline
int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
{
if (atomic_read(val) == 0)
return 0;
return out_of_line_wait_on_atomic_t(val, action, mode);
}
#endif

88
kernel/wait.c

@ -287,3 +287,91 @@ wait_queue_head_t *bit_waitqueue(void *word, int bit)
return &zone->wait_table[hash_long(val, zone->wait_table_bits)];
}
EXPORT_SYMBOL(bit_waitqueue);
/*
* Manipulate the atomic_t address to produce a better bit waitqueue table hash
* index (we're keying off bit -1, but that would produce a horrible hash
* value).
*/
static inline wait_queue_head_t *atomic_t_waitqueue(atomic_t *p)
{
if (BITS_PER_LONG == 64) {
unsigned long q = (unsigned long)p;
return bit_waitqueue((void *)(q & ~1), q & 1);
}
return bit_waitqueue(p, 0);
}
static int wake_atomic_t_function(wait_queue_t *wait, unsigned mode, int sync,
void *arg)
{
struct wait_bit_key *key = arg;
struct wait_bit_queue *wait_bit
= container_of(wait, struct wait_bit_queue, wait);
atomic_t *val = key->flags;
if (wait_bit->key.flags != key->flags ||
wait_bit->key.bit_nr != key->bit_nr ||
atomic_read(val) != 0)
return 0;
return autoremove_wake_function(wait, mode, sync, key);
}
/*
* To allow interruptible waiting and asynchronous (i.e. nonblocking) waiting,
* the actions of __wait_on_atomic_t() are permitted return codes. Nonzero
* return codes halt waiting and return.
*/
static __sched
int __wait_on_atomic_t(wait_queue_head_t *wq, struct wait_bit_queue *q,
int (*action)(atomic_t *), unsigned mode)
{
atomic_t *val;
int ret = 0;
do {
prepare_to_wait(wq, &q->wait, mode);
val = q->key.flags;
if (atomic_read(val) == 0)
ret = (*action)(val);
} while (!ret && atomic_read(val) != 0);
finish_wait(wq, &q->wait);
return ret;
}
#define DEFINE_WAIT_ATOMIC_T(name, p) \
struct wait_bit_queue name = { \
.key = __WAIT_ATOMIC_T_KEY_INITIALIZER(p), \
.wait = { \
.private = current, \
.func = wake_atomic_t_function, \
.task_list = \
LIST_HEAD_INIT((name).wait.task_list), \
}, \
}
__sched int out_of_line_wait_on_atomic_t(atomic_t *p, int (*action)(atomic_t *),
unsigned mode)
{
wait_queue_head_t *wq = atomic_t_waitqueue(p);
DEFINE_WAIT_ATOMIC_T(wait, p);
return __wait_on_atomic_t(wq, &wait, action, mode);
}
EXPORT_SYMBOL(out_of_line_wait_on_atomic_t);
/**
* wake_up_atomic_t - Wake up a waiter on a atomic_t
* @word: The word being waited on, a kernel virtual address
* @bit: The bit of the word being waited on
*
* Wake up anyone waiting for the atomic_t to go to zero.
*
* Abuse the bit-waker function and its waitqueue hash table set (the atomic_t
* check is done by the waiter's wake function, not the by the waker itself).
*/
void wake_up_atomic_t(atomic_t *p)
{
__wake_up_bit(atomic_t_waitqueue(p), p, WAIT_ATOMIC_T_BIT_NR);
}
EXPORT_SYMBOL(wake_up_atomic_t);