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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-02 09:52:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-02 09:52:47 -0700
commitbcd7351e83728859833e3c5b8aae9a2816914e4b (patch)
tree940487a8b04f6ec79212836954d9c1389a9d80ed
parent6072a93b98e660211c4b46a8381833425bdcf7b7 (diff)
parentdcfae32f892f03dee9896b19d1960c1ecd3f0583 (diff)
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 #8). 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 #7). 6) Wrap checks on object state (cleanup for #7). 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()
Diffstat
-rw-r--r--fs/cachefiles/interface.c13
-rw-r--r--fs/cachefiles/namei.c10
-rw-r--r--fs/cachefiles/xattr.c6
-rw-r--r--fs/fscache/cache.c34
-rw-r--r--fs/fscache/cookie.c93
-rw-r--r--fs/fscache/fsdef.c1
-rw-r--r--fs/fscache/internal.h11
-rw-r--r--fs/fscache/main.c11
-rw-r--r--fs/fscache/netfs.c1
-rw-r--r--fs/fscache/object-list.c103
-rw-r--r--fs/fscache/object.c1106
-rw-r--r--fs/fscache/operation.c37
-rw-r--r--fs/fscache/page.c65
-rw-r--r--include/linux/fscache-cache.h175
-rw-r--r--include/linux/wait.h24
-rw-r--r--kernel/wait.c88
16 files changed, 956 insertions, 822 deletions
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 746ce532e13..d4c1206af9f 100644
--- a/fs/cachefiles/interface.c
+++ b/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);
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 8c01c5fcdf7..25badd1aec5 100644
--- a/fs/cachefiles/namei.c
+++ b/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));
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index 73b46288b54..2476e516260 100644
--- a/fs/cachefiles/xattr.c
+++ b/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,
diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c
index b52aed1dca9..f7cff367db7 100644
--- a/fs/fscache/cache.c
+++ b/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);
+ spin_lock(&cache->object_list_lock);
- _debug("withdraw %p", object->cookie);
+ 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);
- spin_lock(&object->lock);
- spin_unlock(&cache->object_list_lock);
- fscache_raise_event(object, FSCACHE_OBJECT_EV_WITHDRAW);
- spin_unlock(&object->lock);
+ _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();
- spin_lock(&cache->object_list_lock);
}
-
- spin_unlock(&cache->object_list_lock);
}
/**
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index e2cba1f60c2..0e91a3c9fdb 100644
--- a/fs/fscache/cookie.c
+++ b/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);
- }
-
- event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE;
+ /* 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);
-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);
diff --git a/fs/fscache/fsdef.c b/fs/fscache/fsdef.c
index f5b4baee735..10a2ade0bdf 100644
--- a/fs/fscache/fsdef.c
+++ b/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,
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index ee38fef4be5..12d505bedb5 100644
--- a/fs/fscache/internal.h
+++ b/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);
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
index f9d856773f7..7c27907e650 100644
--- a/fs/fscache/main.c
+++ b/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;
+}
diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index e028b8eb1c4..b1bb6117473 100644
--- a/fs/fscache/netfs.c
+++ b/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;
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index f27c89d1788..e1959efad64 100644
--- a/fs/fscache/object-list.c
+++ b/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;
}
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 50d41c18021..86d75a60b20 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -15,52 +15,131 @@
#define FSCACHE_DEBUG_LEVEL COOKIE
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/prefetch.h>
#include "internal.h"
-const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = {
- [FSCACHE_OBJECT_INIT] = "OBJECT_INIT",
- [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP",
- [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING",
- [FSCACHE_OBJECT_AVAILABLE] = "OBJECT_AVAILABLE",
- [FSCACHE_OBJECT_ACTIVE] = "OBJECT_ACTIVE",
- [FSCACHE_OBJECT_INVALIDATING] = "OBJECT_INVALIDATING",
- [FSCACHE_OBJECT_UPDATING] = "OBJECT_UPDATING",
- [FSCACHE_OBJECT_DYING] = "OBJECT_DYING",
- [FSCACHE_OBJECT_LC_DYING] = "OBJECT_LC_DYING",
- [FSCACHE_OBJECT_ABORT_INIT] = "OBJECT_ABORT_INIT",
- [FSCACHE_OBJECT_RELEASING] = "OBJECT_RELEASING",
- [FSCACHE_OBJECT_RECYCLING] = "OBJECT_RECYCLING",
- [FSCACHE_OBJECT_WITHDRAWING] = "OBJECT_WITHDRAWING",
- [FSCACHE_OBJECT_DEAD] = "OBJECT_DEAD",
+static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *, int);
+static const struct fscache_state *fscache_kill_dependents(struct fscache_object *, int);
+static const struct fscache_state *fscache_drop_object(struct fscache_object *, int);
+static const struct fscache_state *fscache_initialise_object(struct fscache_object *, int);
+static const struct fscache_state *fscache_invalidate_object(struct fscache_object *, int);
+static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *, int);
+static const struct fscache_state *fscache_kill_object(struct fscache_object *, int);
+static const struct fscache_state *fscache_lookup_failure(struct fscache_object *, int);
+static const struct fscache_state *fscache_look_up_object(struct fscache_object *, int);
+static const struct fscache_state *fscache_object_available(struct fscache_object *, int);
+static const struct fscache_state *fscache_parent_ready(struct fscache_object *, int);
+static const struct fscache_state *fscache_update_object(struct fscache_object *, int);
+
+#define __STATE_NAME(n) fscache_osm_##n
+#define STATE(n) (&__STATE_NAME(n))
+
+/*
+ * Define a work state. Work states are execution states. No event processing
+ * is performed by them. The function attached to a work state returns a
+ * pointer indicating the next state to which the state machine should
+ * transition. Returning NO_TRANSIT repeats the current state, but goes back
+ * to the scheduler first.
+ */
+#define WORK_STATE(n, sn, f) \
+ const struct fscache_state __STATE_NAME(n) = { \
+ .name = #n, \
+ .short_name = sn, \
+ .work = f \
+ }
+
+/*
+ * Returns from work states.
+ */
+#define transit_to(state) ({ prefetch(&STATE(state)->work); STATE(state); })
+
+#define NO_TRANSIT ((struct fscache_state *)NULL)
+
+/*
+ * Define a wait state. Wait states are event processing states. No execution
+ * is performed by them. Wait states are just tables of "if event X occurs,
+ * clear it and transition to state Y". The dispatcher returns to the
+ * scheduler if none of the events in which the wait state has an interest are
+ * currently pending.
+ */
+#define WAIT_STATE(n, sn, ...) \
+ const struct fscache_state __STATE_NAME(n) = { \
+ .name = #n, \
+ .short_name = sn, \
+ .work = NULL, \
+ .transitions = { __VA_ARGS__, { 0, NULL } } \
+ }
+
+#define TRANSIT_TO(state, emask) \
+ { .events = (emask), .transit_to = STATE(state) }
+
+/*
+ * The object state machine.
+ */
+static WORK_STATE(INIT_OBJECT, "INIT", fscache_initialise_object);
+static WORK_STATE(PARENT_READY, "PRDY", fscache_parent_ready);
+static WORK_STATE(ABORT_INIT, "ABRT", fscache_abort_initialisation);
+static WORK_STATE(LOOK_UP_OBJECT, "LOOK", fscache_look_up_object);
+static WORK_STATE(CREATE_OBJECT, "CRTO", fscache_look_up_object);
+static WORK_STATE(OBJECT_AVAILABLE, "AVBL", fscache_object_available);
+static WORK_STATE(JUMPSTART_DEPS, "JUMP", fscache_jumpstart_dependents);
+
+static WORK_STATE(INVALIDATE_OBJECT, "INVL", fscache_invalidate_object);
+static WORK_STATE(UPDATE_OBJECT, "UPDT", fscache_update_object);
+
+static WORK_STATE(LOOKUP_FAILURE, "LCFL", fscache_lookup_failure);
+static WORK_STATE(KILL_OBJECT, "KILL", fscache_kill_object);
+static WORK_STATE(KILL_DEPENDENTS, "KDEP", fscache_kill_dependents);
+static WORK_STATE(DROP_OBJECT, "DROP", fscache_drop_object);
+static WORK_STATE(OBJECT_DEAD, "DEAD", (void*)2UL);
+
+static WAIT_STATE(WAIT_FOR_INIT, "?INI",
+ TRANSIT_TO(INIT_OBJECT, 1 << FSCACHE_OBJECT_EV_NEW_CHILD));
+
+static WAIT_STATE(WAIT_FOR_PARENT, "?PRN",
+ TRANSIT_TO(PARENT_READY, 1 << FSCACHE_OBJECT_EV_PARENT_READY));
+
+static WAIT_STATE(WAIT_FOR_CMD, "?CMD",
+ TRANSIT_TO(INVALIDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_INVALIDATE),
+ TRANSIT_TO(UPDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_UPDATE),
+ TRANSIT_TO(JUMPSTART_DEPS, 1 << FSCACHE_OBJECT_EV_NEW_CHILD));
+
+static WAIT_STATE(WAIT_FOR_CLEARANCE, "?CLR",
+ TRANSIT_TO(KILL_OBJECT, 1 << FSCACHE_OBJECT_EV_CLEARED));
+
+/*
+ * Out-of-band event transition tables. These are for handling unexpected
+ * events, such as an I/O error. If an OOB event occurs, the state machine
+ * clears and disables the event and forces a transition to the nominated work
+ * state (acurrently executing work states will complete first).
+ *
+ * In such a situation, object->state remembers the state the machine should
+ * have been in/gone to and returning NO_TRANSIT returns to that.
+ */
+static const struct fscache_transition fscache_osm_init_oob[] = {
+ TRANSIT_TO(ABORT_INIT,
+ (1 << FSCACHE_OBJECT_EV_ERROR) |
+ (1 << FSCACHE_OBJECT_EV_KILL)),
+ { 0, NULL }
+};
+
+static const struct fscache_transition fscache_osm_lookup_oob[] = {
+ TRANSIT_TO(LOOKUP_FAILURE,
+ (1 << FSCACHE_OBJECT_EV_ERROR) |
+ (1 << FSCACHE_OBJECT_EV_KILL)),
+ { 0, NULL }
};
-EXPORT_SYMBOL(fscache_object_states);
-
-const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = {
- [FSCACHE_OBJECT_INIT] = "INIT",
- [FSCACHE_OBJECT_LOOKING_UP] = "LOOK",
- [FSCACHE_OBJECT_CREATING] = "CRTN",
- [FSCACHE_OBJECT_AVAILABLE] = "AVBL",
- [FSCACHE_OBJECT_ACTIVE] = "ACTV",
- [FSCACHE_OBJECT_INVALIDATING] = "INVL",
- [FSCACHE_OBJECT_UPDATING] = "UPDT",
- [FSCACHE_OBJECT_DYING] = "DYNG",
- [FSCACHE_OBJECT_LC_DYING] = "LCDY",
- [FSCACHE_OBJECT_ABORT_INIT] = "ABTI",
- [FSCACHE_OBJECT_RELEASING] = "RELS",
- [FSCACHE_OBJECT_RECYCLING] = "RCYC",
- [FSCACHE_OBJECT_WITHDRAWING] = "WTHD",
- [FSCACHE_OBJECT_DEAD] = "DEAD",
+
+static const struct fscache_transition fscache_osm_run_oob[] = {
+ TRANSIT_TO(KILL_OBJECT,
+ (1 << FSCACHE_OBJECT_EV_ERROR) |
+ (1 << FSCACHE_OBJECT_EV_KILL)),
+ { 0, NULL }
};
static int fscache_get_object(struct fscache_object *);
static void fscache_put_object(struct fscache_object *);
-static void fscache_initialise_object(struct fscache_object *);
-static void fscache_lookup_object(struct fscache_object *);
-static void fscache_object_available(struct fscache_object *);
-static void fscache_invalidate_object(struct fscache_object *);
-static void fscache_release_object(struct fscache_object *);
-static void fscache_withdraw_object(struct fscache_object *);
-static void fscache_enqueue_dependents(struct fscache_object *);
+static bool fscache_enqueue_dependents(struct fscache_object *, int);
static void fscache_dequeue_object(struct fscache_object *);
/*
@@ -75,295 +154,116 @@ static inline void fscache_done_parent_op(struct fscache_object *object)
object->debug_id, parent->debug_id, parent->n_ops);
spin_lock_nested(&parent->lock, 1);
- parent->n_ops--;
parent->n_obj_ops--;
+ parent->n_ops--;
if (parent->n_ops == 0)
fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
spin_unlock(&parent->lock);
}
/*
- * Notify netfs of invalidation completion.
+ * Object state machine dispatcher.
*/
-static inline void fscache_invalidation_complete(struct fscache_cookie *cookie)
+static void fscache_object_sm_dispatcher(struct fscache_object *object)
{
- if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
- wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING);
-}
-
-/*
- * process events that have been sent to an object's state machine
- * - initiates parent lookup
- * - does object lookup
- * - does object creation
- * - does object recycling and retirement
- * - does object withdrawal
- */
-static void fscache_object_state_machine(struct fscache_object *object)
-{
- enum fscache_object_state new_state;
- struct fscache_cookie *cookie;
- int event;
+ const struct fscache_transition *t;
+ const struct fscache_state *state, *new_state;
+ unsigned long events, event_mask;
+ int event = -1;
ASSERT(object != NULL);
_enter("{OBJ%x,%s,%lx}",
- object->debug_id, fscache_object_states[object->state],
- object->events);
-
- switch (object->state) {
- /* wait for the parent object to become ready */
- case FSCACHE_OBJECT_INIT:
- object->event_mask =
- FSCACHE_OBJECT_EVENTS_MASK &
- ~(1 << FSCACHE_OBJECT_EV_CLEARED);
- fscache_initialise_object(object);
- goto done;
-
- /* look up the object metadata on disk */
- case FSCACHE_OBJECT_LOOKING_UP:
- fscache_lookup_object(object);
- goto lookup_transit;
-
- /* create the object metadata on disk */
- case FSCACHE_OBJECT_CREATING:
- fscache_lookup_object(object);
- goto lookup_transit;
-
- /* handle an object becoming available; start pending
- * operations and queue dependent operations for processing */
- case FSCACHE_OBJECT_AVAILABLE:
- fscache_object_available(object);
- goto active_transit;
-
- /* normal running state */
- case FSCACHE_OBJECT_ACTIVE:
- goto active_transit;
-
- /* Invalidate an object on disk */
- case FSCACHE_OBJECT_INVALIDATING:
- clear_bit(FSCACHE_OBJECT_EV_INVALIDATE, &object->events);
- fscache_stat(&fscache_n_invalidates_run);
- fscache_stat(&fscache_n_cop_invalidate_object);
- fscache_invalidate_object(object);
- fscache_stat_d(&fscache_n_cop_invalidate_object);
- fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE);
- goto active_transit;
-
- /* update the object metadata on disk */
- case FSCACHE_OBJECT_UPDATING:
- clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events);
- fscache_stat(&fscache_n_updates_run);
- fscache_stat(&fscache_n_cop_update_object);
- object->cache->ops->update_object(object);
- fscache_stat_d(&fscache_n_cop_update_object);
- goto active_transit;
-
- /* handle an object dying during lookup or creation */
- case FSCACHE_OBJECT_LC_DYING:
- object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
- fscache_stat(&fscache_n_cop_lookup_complete);
- object->cache->ops->lookup_complete(object);
- fscache_stat_d(&fscache_n_cop_lookup_complete);
-
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_DYING;
- cookie = object->cookie;
- if (cookie) {
- if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP,
- &cookie->flags))
- wake_up_bit(&cookie->flags,
- FSCACHE_COOKIE_LOOKING_UP);
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
- &cookie->flags))
- wake_up_bit(&cookie->flags,
- FSCACHE_COOKIE_CREATING);
+ object->debug_id, object->state->name, object->events);
+
+ event_mask = object->event_mask;
+restart:
+ object->event_mask = 0; /* Mask normal event handling */
+ state = object->state;
+restart_masked:
+ events = object->events;
+
+ /* Handle any out-of-band events (typically an error) */
+ if (events & object->oob_event_mask) {
+ _debug("{OBJ%x} oob %lx",
+ object->debug_id, events & object->oob_event_mask);
+ for (t = object->oob_table; t->events; t++) {
+ if (events & t->events) {
+ state = t->transit_to;
+ ASSERT(state->work != NULL);
+ event = fls(events & t->events) - 1;
+ __clear_bit(event, &object->oob_event_mask);
+ clear_bit(event, &object->events);
+ goto execute_work_state;
+ }
}
- spin_unlock(&object->lock);
+ }
- fscache_done_parent_op(object);
+ /* Wait states are just transition tables */
+ if (!state->work) {
+ if (events & event_mask) {
+ for (t = state->transitions; t->events; t++) {
+ if (events & t->events) {
+ new_state = t->transit_to;
+ event = fls(events & t->events) - 1;
+ clear_bit(event, &object->events);
+ _debug("{OBJ%x} ev %d: %s -> %s",
+ object->debug_id, event,
+ state->name, new_state->name);
+ object->state = state = new_state;
+ goto execute_work_state;
+ }
+ }
- /* wait for completion of all active operations on this object
- * and the death of all child objects of this object */
- case FSCACHE_OBJECT_DYING:
- dying:
- clear_bit(FSCACHE_OBJECT_EV_CLEARED, &object->events);
- spin_lock(&object->lock);
- _debug("dying OBJ%x {%d,%d}",
- object->debug_id, object->n_ops, object->n_children);
- if (object->n_ops == 0 && object->n_children == 0) {
- object->event_mask &=
- ~(1 << FSCACHE_OBJECT_EV_CLEARED);
- object->event_mask |=
- (1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR);
- } else {
- object->event_mask &=
- ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR));
- object->event_mask |=
- 1 << FSCACHE_OBJECT_EV_CLEARED;
+ /* The event mask didn't include all the tabled bits */
+ BUG();
}
- spin_unlock(&object->lock);
- fscache_enqueue_dependents(object);
- fscache_start_operations(object);
- goto terminal_transit;
-
- /* handle an abort during initialisation */
- case FSCACHE_OBJECT_ABORT_INIT:
- _debug("handle abort init %lx", object->events);
- object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
-
- spin_lock(&object->lock);
- fscache_dequeue_object(object);
-
- object->state = FSCACHE_OBJECT_DYING;
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
- &object->cookie->flags))
- wake_up_bit(&object->cookie->flags,
- FSCACHE_COOKIE_CREATING);
- spin_unlock(&object->lock);
- goto dying;
-
- /* handle the netfs releasing an object and possibly marking it
- * obsolete too */
- case FSCACHE_OBJECT_RELEASING:
- case FSCACHE_OBJECT_RECYCLING:
- object->event_mask &=
- ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR));
- fscache_release_object(object);
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_DEAD;
- spin_unlock(&object->lock);
- fscache_stat(&fscache_n_object_dead);
- goto terminal_transit;
-
- /* handle the parent cache of this object being withdrawn from
- * active service */
- case FSCACHE_OBJECT_WITHDRAWING:
- object->event_mask &=
- ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR));
- fscache_withdraw_object(object);
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_DEAD;
- spin_unlock(&object->lock);
- fscache_stat(&fscache_n_object_dead);
- goto terminal_transit;
-
- /* complain about the object being woken up once it is
- * deceased */
- case FSCACHE_OBJECT_DEAD:
- printk(KERN_ERR "FS-Cache:"
- " Unexpected event in dead state %lx\n",
- object->events & object->event_mask);
- BUG();
-
- default:
- printk(KERN_ERR "FS-Cache: Unknown object state %u\n",
- object->state);
- BUG();
- }
-
- /* determine the transition from a lookup state */
-lookup_transit:
- event = fls(object->events & object->event_mask) - 1;
- switch (event) {
- case FSCACHE_OBJECT_EV_WITHDRAW:
- case FSCACHE_OBJECT_EV_RETIRE:
- case FSCACHE_OBJECT_EV_RELEASE:
- case FSCACHE_OBJECT_EV_ERROR:
- new_state = FSCACHE_OBJECT_LC_DYING;
- goto change_state;
- case FSCACHE_OBJECT_EV_INVALIDATE:
- new_state = FSCACHE_OBJECT_INVALIDATING;
- goto change_state;
- case FSCACHE_OBJECT_EV_REQUEUE:
- goto done;
- case -1:
- goto done; /* sleep until event */
- default:
- goto unsupported_event;
+ /* Randomly woke up */
+ goto unmask_events;
}
- /* determine the transition from an active state */
-active_transit:
- event = fls(object->events & object->event_mask) - 1;
- switch (event) {
- case FSCACHE_OBJECT_EV_WITHDRAW:
- case FSCACHE_OBJECT_EV_RETIRE:
- case FSCACHE_OBJECT_EV_RELEASE:
- case FSCACHE_OBJECT_EV_ERROR:
- new_state = FSCACHE_OBJECT_DYING;
- goto change_state;
- case FSCACHE_OBJECT_EV_INVALIDATE:
- new_state = FSCACHE_OBJECT_INVALIDATING;
- goto change_state;
- case FSCACHE_OBJECT_EV_UPDATE:
- new_state = FSCACHE_OBJECT_UPDATING;
- goto change_state;
- case -1:
- new_state = FSCACHE_OBJECT_ACTIVE;
- goto change_state; /* sleep until event */
- default:
- goto unsupported_event;
- }
+execute_work_state:
+ _debug("{OBJ%x} exec %s", object->debug_id, state->name);
- /* determine the transition from a terminal state */
-terminal_transit:
- event = fls(object->events & object->event_mask) - 1;
- switch (event) {
- case FSCACHE_OBJECT_EV_WITHDRAW:
- new_state = FSCACHE_OBJECT_WITHDRAWING;
- goto change_state;
- case FSCACHE_OBJECT_EV_RETIRE:
- new_state = FSCACHE_OBJECT_RECYCLING;
- goto change_state;
- case FSCACHE_OBJECT_EV_RELEASE:
- new_state = FSCACHE_OBJECT_RELEASING;
- goto change_state;
- case FSCACHE_OBJECT_EV_ERROR:
- new_state = FSCACHE_OBJECT_WITHDRAWING;
- goto change_state;
- case FSCACHE_OBJECT_EV_CLEARED:
- new_state = FSCACHE_OBJECT_DYING;
- goto change_state;
- case -1:
- goto done; /* sleep until event */
- default:
- goto unsupported_event;
+ new_state = state->work(object, event);
+ event = -1;
+ if (new_state == NO_TRANSIT) {
+ _debug("{OBJ%x} %s notrans", object->debug_id, state->name);
+ fscache_enqueue_object(object);
+ event_mask = object->oob_event_mask;
+ goto unmask_events;
}
-change_state:
- spin_lock(&object->lock);
- object->state = new_state;
- spin_unlock(&object->lock);
+ _debug("{OBJ%x} %s -> %s",
+ object->debug_id, state->name, new_state->name);
+ object->state = state = new_state;
-done:
- _leave(" [->%s]", fscache_object_states[object->state]);
- return;
+ if (state->work) {
+ if (unlikely(state->work == ((void *)2UL))) {
+ _leave(" [dead]");
+ return;
+ }
+ goto restart_masked;
+ }
-unsupported_event:
- printk(KERN_ERR "FS-Cache:"
- " Unsupported event %d [%lx/%lx] in state %s\n",
- event, object->events, object->event_mask,
- fscache_object_states[object->state]);
- BUG();
+ /* Transited to wait state */
+ event_mask = object->oob_event_mask;
+ for (t = state->transitions; t->events; t++)
+ event_mask |= t->events;
+
+unmask_events:
+ object->event_mask = event_mask;
+ smp_mb();
+ events = object->events;
+ if (events & event_mask)
+ goto restart;
+ _leave(" [msk %lx]", event_mask);
}
/*
* execute an object
*/
-void fscache_object_work_func(struct work_struct *work)
+static void fscache_object_work_func(struct work_struct *work)
{
struct fscache_object *object =
container_of(work, struct fscache_object, work);
@@ -372,14 +272,70 @@ void fscache_object_work_func(struct work_struct *work)
_enter("{OBJ%x}", object->debug_id);
start = jiffies;
- fscache_object_state_machine(object);
+ fscache_object_sm_dispatcher(object);
fscache_hist(fscache_objs_histogram, start);
- if (object->events & object->event_mask)
- fscache_enqueue_object(object);
- clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
fscache_put_object(object);
}
-EXPORT_SYMBOL(fscache_object_work_func);
+
+/**
+ * fscache_object_init - Initialise a cache object description
+ * @object: Object description
+ * @cookie: Cookie object will be attached to
+ * @cache: Cache in which backing object will be found
+ *
+ * Initialise a cache object description to its basic values.
+ *
+ * See Documentation/filesystems/caching/backend-api.txt for a complete
+ * description.
+ */
+void fscache_object_init(struct fscache_object *object,
+ struct fscache_cookie *cookie,
+ struct fscache_cache *cache)
+{
+ const struct fscache_transition *t;
+
+ atomic_inc(&cache->object_count);
+
+ object->state = STATE(WAIT_FOR_INIT);
+ object->oob_table = fscache_osm_init_oob;
+ object->flags = 1 << FSCACHE_OBJECT_IS_LIVE;
+ 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 = 0;
+ object->store_limit = 0;
+ object->store_limit_l = 0;
+ object->cache = cache;
+ object->cookie = cookie;
+ object->parent = NULL;
+
+ object->oob_event_mask = 0;
+ for (t = object->oob_table; t->events; t++)
+ object->oob_event_mask |= t->events;
+ object->event_mask = object->oob_event_mask;
+ for (t = object->state->transitions; t->events; t++)
+ object->event_mask |= t->events;
+}
+EXPORT_SYMBOL(fscache_object_init);
+
+/*
+ * Abort object initialisation before we start it.
+ */
+static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *object,
+ int event)
+{
+ _enter("{OBJ%x},%d", object->debug_id, event);
+
+ object->oob_event_mask = 0;
+ fscache_dequeue_object(object);
+ return transit_to(KILL_OBJECT);
+}
/*
* initialise an object
@@ -387,130 +343,136 @@ EXPORT_SYMBOL(fscache_object_work_func);
* immediately to do a creation
* - we may need to start the process of creating a parent and we need to wait
* for the parent's lookup and creation to complete if it's not there yet
- * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
- * leaf-most cookies of the object and all its children
*/
-static void fscache_initialise_object(struct fscache_object *object)
+static const struct fscache_state *fscache_initialise_object(struct fscache_object *object,
+ int event)
{
struct fscache_object *parent;
+ bool success;
- _enter("");
- ASSERT(object->cookie != NULL);
- ASSERT(object->cookie->parent != NULL);
-
- if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_WITHDRAW))) {
- _debug("abort init %lx", object->events);
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_ABORT_INIT;
- spin_unlock(&object->lock);
- return;
- }
+ _enter("{OBJ%x},%d", object->debug_id, event);
- spin_lock(&object->cookie->lock);
- spin_lock_nested(&object->cookie->parent->lock, 1);
+ ASSERT(list_empty(&object->dep_link));
parent = object->parent;
if (!parent) {
- _debug("no parent");
- set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
- } else {
- spin_lock(&object->lock);
- spin_lock_nested(&parent->lock, 1);
- _debug("parent %s", fscache_object_states[parent->state]);
-
- if (parent->state >= FSCACHE_OBJECT_DYING) {
- _debug("bad parent");
- set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
- } else if (parent->state < FSCACHE_OBJECT_AVAILABLE) {
- _debug("wait");
-
- /* we may get woken up in this state by child objects
- * binding on to us, so we need to make sure we don't
- * add ourself to the list multiple times */
- if (list_empty(&object->dep_link)) {
- fscache_stat(&fscache_n_cop_grab_object);
- object->cache->ops->grab_object(object);
- fscache_stat_d(&fscache_n_cop_grab_object);
- list_add(&object->dep_link,
- &parent->dependents);
-
- /* fscache_acquire_non_index_cookie() uses this
- * to wake the chain up */
- if (parent->state == FSCACHE_OBJECT_INIT)
- fscache_enqueue_object(parent);
- }
- } else {
- _debug("go");
- parent->n_ops++;
- parent->n_obj_ops++;
- object->lookup_jif = jiffies;
- object->state = FSCACHE_OBJECT_LOOKING_UP;
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
- }
+ _leave(" [no parent]");
+ return transit_to(DROP_OBJECT);
+ }
- spin_unlock(&parent->lock);
- spin_unlock(&object->lock);
+ _debug("parent: %s of:%lx", parent->state->name, parent->flags);
+
+ if (fscache_object_is_dying(parent)) {
+ _leave(" [bad parent]");
+ return transit_to(DROP_OBJECT);
}
- spin_unlock(&object->cookie->parent->lock);
- spin_unlock(&object->cookie->lock);
+ if (fscache_object_is_available(parent)) {
+ _leave(" [ready]");
+ return transit_to(PARENT_READY);
+ }
+
+ _debug("wait");
+
+ spin_lock(&parent->lock);
+ fscache_stat(&fscache_n_cop_grab_object);
+ success = false;
+ if (fscache_object_is_live(parent) &&
+ object->cache->ops->grab_object(object)) {
+ list_add(&object->dep_link, &parent->dependents);
+ success = true;
+ }
+ fscache_stat_d(&fscache_n_cop_grab_object);
+ spin_unlock(&parent->lock);
+ if (!success) {
+ _leave(" [grab failed]");
+ return transit_to(DROP_OBJECT);
+ }
+
+ /* fscache_acquire_non_index_cookie() uses this
+ * to wake the chain up */
+ fscache_raise_event(parent, FSCACHE_OBJECT_EV_NEW_CHILD);
+ _leave(" [wait]");
+ return transit_to(WAIT_FOR_PARENT);
+}
+
+/*
+ * Once the parent object is ready, we should kick off our lookup op.
+ */
+static const struct fscache_state *fscache_parent_ready(struct fscache_object *object,
+ int event)
+{
+ struct fscache_object *parent = object->parent;
+
+ _enter("{OBJ%x},%d", object->debug_id, event);
+
+ ASSERT(parent != NULL);
+
+ spin_lock(&parent->lock);
+ parent->n_ops++;
+ parent->n_obj_ops++;
+ object->lookup_jif = jiffies;
+ spin_unlock(&parent->lock);
+
_leave("");
+ return transit_to(LOOK_UP_OBJECT);
}
/*
* look an object up in the cache from which it was allocated
* - we hold an "access lock" on the parent object, so the parent object cannot
* be withdrawn by either party till we've finished
- * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
- * leaf-most cookies of the object and all its children
*/
-static void fscache_lookup_object(struct fscache_object *object)
+static const struct fscache_state *fscache_look_up_object(struct fscache_object *object,
+ int event)
{
struct fscache_cookie *cookie = object->cookie;
- struct fscache_object *parent;
+ struct fscache_object *parent = object->parent;
int ret;
- _enter("");
+ _enter("{OBJ%x},%d", object->debug_id, event);
+
+ object->oob_table = fscache_osm_lookup_oob;
- parent = object->parent;
ASSERT(parent != NULL);
ASSERTCMP(parent->n_ops, >, 0);
ASSERTCMP(parent->n_obj_ops, >, 0);
/* make sure the parent is still available */
- ASSERTCMP(parent->state, >=, FSCACHE_OBJECT_AVAILABLE);
-
- if (parent->state >= FSCACHE_OBJECT_DYING ||
- test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
- _debug("unavailable");
- set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
- _leave("");
- return;
+ ASSERT(fscache_object_is_available(parent));
+
+ if (fscache_object_is_dying(parent) ||
+ test_bit(FSCACHE_IOERROR, &object->cache->flags) ||
+ !fscache_use_cookie(object)) {
+ _leave(" [unavailable]");
+ return transit_to(LOOKUP_FAILURE);
}
- _debug("LOOKUP \"%s/%s\" in \"%s\"",
- parent->cookie->def->name, cookie->def->name,
- object->cache->tag->name);
+ _debug("LOOKUP \"%s\" in \"%s\"",
+ cookie->def->name, object->cache->tag->name);
fscache_stat(&fscache_n_object_lookups);
fscache_stat(&fscache_n_cop_lookup_object);
ret = object->cache->ops->lookup_object(object);
fscache_stat_d(&fscache_n_cop_lookup_object);
- if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events))
- set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
+ fscache_unuse_cookie(object);
if (ret == -ETIMEDOUT) {
/* probably stuck behind another object, so move this one to
* the back of the queue */
fscache_stat(&fscache_n_object_lookups_timed_out);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+ _leave(" [timeout]");
+ return NO_TRANSIT;
}
- _leave("");
+ if (ret < 0) {
+ _leave(" [error]");
+ return transit_to(LOOKUP_FAILURE);
+ }
+
+ _leave(" [ok]");
+ return transit_to(OBJECT_AVAILABLE);
}
/**
@@ -524,32 +486,20 @@ void fscache_object_lookup_negative(struct fscache_object *object)
{
struct fscache_cookie *cookie = object->cookie;
- _enter("{OBJ%x,%s}",
- object->debug_id, fscache_object_states[object->state]);
+ _enter("{OBJ%x,%s}", object->debug_id, object->state->name);
- spin_lock(&object->lock);
- if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
+ if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
fscache_stat(&fscache_n_object_lookups_negative);
- /* transit here to allow write requests to begin stacking up
- * and read requests to begin returning ENODATA */
- object->state = FSCACHE_OBJECT_CREATING;
- spin_unlock(&object->lock);
-
- set_bit(FSCACHE_COOKIE_PENDING_FILL, &cookie->flags);
+ /* Allow write requests to begin stacking up and read requests to begin
+ * returning ENODATA.
+ */
set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
_debug("wake up lookup %p", &cookie->flags);
- smp_mb__before_clear_bit();
- clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
- smp_mb__after_clear_bit();
+ clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
- } else {
- ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
- spin_unlock(&object->lock);
}
-
_leave("");
}
EXPORT_SYMBOL(fscache_object_lookup_negative);
@@ -568,38 +518,26 @@ void fscache_obtained_object(struct fscache_object *object)
{
struct fscache_cookie *cookie = object->cookie;
- _enter("{OBJ%x,%s}",
- object->debug_id, fscache_object_states[object->state]);
+ _enter("{OBJ%x,%s}", object->debug_id, object->state->name);
/* if we were still looking up, then we must have a positive lookup
* result, in which case there may be data available */
- spin_lock(&object->lock);
- if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
+ if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
fscache_stat(&fscache_n_object_lookups_positive);
- clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
+ /* We do (presumably) have data */
+ clear_bit_unlock(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
- object->state = FSCACHE_OBJECT_AVAILABLE;
- spin_unlock(&object->lock);
-
- smp_mb__before_clear_bit();
- clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
- smp_mb__after_clear_bit();
+ /* Allow write requests to begin stacking up and read requests
+ * to begin shovelling data.
+ */
+ clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
} else {
- ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
fscache_stat(&fscache_n_object_created);
-
- object->state = FSCACHE_OBJECT_AVAILABLE;
- spin_unlock(&object->lock);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
- smp_wmb();
}
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &cookie->flags))
- wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING);
-
+ set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
_leave("");
}
EXPORT_SYMBOL(fscache_obtained_object);
@@ -607,15 +545,14 @@ EXPORT_SYMBOL(fscache_obtained_object);
/*
* handle an object that has just become available
*/
-static void fscache_object_available(struct fscache_object *object)
+static const struct fscache_state *fscache_object_available(struct fscache_object *object,
+ int event)
{
- _enter("{OBJ%x}", object->debug_id);
+ _enter("{OBJ%x},%d", object->debug_id, event);
- spin_lock(&object->lock);
+ object->oob_table = fscache_osm_run_oob;
- if (object->cookie &&
- test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
- wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING);
+ spin_lock(&object->lock);
fscache_done_parent_op(object);
if (object->n_in_progress == 0) {
@@ -631,130 +568,158 @@ static void fscache_object_available(struct fscache_object *object)
fscache_stat(&fscache_n_cop_lookup_complete);
object->cache->ops->lookup_complete(object);
fscache_stat_d(&fscache_n_cop_lookup_complete);
- fscache_enqueue_dependents(object);
fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif);
fscache_stat(&fscache_n_object_avail);
_leave("");
+ return transit_to(JUMPSTART_DEPS);
}
/*
- * drop an object's attachments
+ * Wake up this object's dependent objects now that we've become available.
*/
-static void fscache_drop_object(struct fscache_object *object)
+static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *object,
+ int event)
{
- struct fscache_object *parent = object->parent;
- struct fscache_cache *cache = object->cache;
+ _enter("{OBJ%x},%d", object->debug_id, event);
- _enter("{OBJ%x,%d}", object->debug_id, object->n_children);
+ if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_PARENT_READY))
+ return NO_TRANSIT; /* Not finished; requeue */
+ return transit_to(WAIT_FOR_CMD);
+}
- ASSERTCMP(object->cookie, ==, NULL);
- ASSERT(hlist_unhashed(&object->cookie_link));
+/*
+ * Handle lookup or creation failute.
+ */
+static const struct fscache_state *fscache_lookup_failure(struct fscache_object *object,
+ int event)
+{
+ struct fscache_cookie *cookie;
- spin_lock(&cache->object_list_lock);
- list_del_init(&object->cache_link);
- spin_unlock(&cache->object_list_lock);
+ _enter("{OBJ%x},%d", object->debug_id, event);
- fscache_stat(&fscache_n_cop_drop_object);
- cache->ops->drop_object(object);
- fscache_stat_d(&fscache_n_cop_drop_object);
+ object->oob_event_mask = 0;
- if (parent) {
- _debug("release parent OBJ%x {%d}",
- parent->debug_id, parent->n_children);
+ fscache_stat(&fscache_n_cop_lookup_complete);
+ object->cache->ops->lookup_complete(object);
+ fscache_stat_d(&fscache_n_cop_lookup_complete);
- spin_lock(&parent->lock);
- parent->n_children--;
- if (parent->n_children == 0)
- fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
- spin_unlock(&parent->lock);
- object->parent = NULL;
+ cookie = object->cookie;
+ set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
+ if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags))
+ wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
+
+ fscache_done_parent_op(object);
+ return transit_to(KILL_OBJECT);
+}
+
+/*
+ * Wait for completion of all active operations on this object and the death of
+ * all child objects of this object.
+ */
+static const struct fscache_state *fscache_kill_object(struct fscache_object *object,
+ int event)
+{
+ _enter("{OBJ%x,%d,%d},%d",
+ object->debug_id, object->n_ops, object->n_children, event);
+
+ clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
+ object->oob_event_mask = 0;
+
+ if (list_empty(&object->dependents) &&
+ object->n_ops == 0 &&
+ object->n_children == 0)
+ return transit_to(DROP_OBJECT);
+
+ if (object->n_in_progress == 0) {
+ spin_lock(&object->lock);
+ if (object->n_ops > 0 && object->n_in_progress == 0)
+ fscache_start_operations(object);
+ spin_unlock(&object->lock);
}
- /* this just shifts the object release to the work processor */
- fscache_put_object(object);
+ if (!list_empty(&object->dependents))
+ return transit_to(KILL_DEPENDENTS);
- _leave("");
+ return transit_to(WAIT_FOR_CLEARANCE);
}
/*
- * release or recycle an object that the netfs has discarded
+ * Kill dependent objects.
*/
-static void fscache_release_object(struct fscache_object *object)
+static const struct fscache_state *fscache_kill_dependents(struct fscache_object *object,
+ int event)
{
- _enter("");
+ _enter("{OBJ%x},%d", object->debug_id, event);
- fscache_drop_object(object);
+ if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_KILL))
+ return NO_TRANSIT; /* Not finished */
+ return transit_to(WAIT_FOR_CLEARANCE);
}
/*
- * withdraw an object from active service
+ * Drop an object's attachments
*/
-static void fscache_withdraw_object(struct fscache_object *object)
+static const struct fscache_state *fscache_drop_object(struct fscache_object *object,
+ int event)
{
- struct fscache_cookie *cookie;
- bool detached;
+ struct fscache_object *parent = object->parent;
+ struct fscache_cookie *cookie = object->cookie;
+ struct fscache_cache *cache = object->cache;
+ bool awaken = false;
- _enter("");
+ _enter("{OBJ%x,%d},%d", object->debug_id, object->n_children, event);
- spin_lock(&object->lock);
- cookie = object->cookie;
- if (cookie) {
- /* need to get the cookie lock before the object lock, starting
- * from the object pointer */
- atomic_inc(&cookie->usage);
- spin_unlock(&object->lock);
+ ASSERT(cookie != NULL);
+ ASSERT(!hlist_unhashed(&object->cookie_link));
- detached = false;
- spin_lock(&cookie->lock);
- spin_lock(&object->lock);
+ /* Make sure the cookie no longer points here and that the netfs isn't
+ * waiting for us.
+ */
+ spin_lock(&cookie->lock);
+ hlist_del_init(&object->cookie_link);
+ if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
+ awaken = true;
+ spin_unlock(&cookie->lock);
- if (object->cookie == cookie) {
- hlist_del_init(&object->cookie_link);
- object->cookie = NULL;
- fscache_invalidation_complete(cookie);
- detached = true;
- }
- spin_unlock(&cookie->lock);
- fscache_cookie_put(cookie);
- if (detached)
- fscache_cookie_put(cookie);
- }
+ if (awaken)
+ wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING);
+ /* Prevent a race with our last child, which has to signal EV_CLEARED
+ * before dropping our spinlock.
+ */
+ spin_lock(&object->lock);
spin_unlock(&object->lock);
- fscache_drop_object(object);
-}
+ /* Discard from the cache's collection of objects */
+ spin_lock(&cache->object_list_lock);
+ list_del_init(&object->cache_link);
+ spin_unlock(&cache->object_list_lock);
-/*
- * withdraw an object from active service at the behest of the cache
- * - need break the links to a cached object cookie
- * - called under two situations:
- * (1) recycler decides to reclaim an in-use object
- * (2) a cache is unmounted
- * - have to take care as the cookie can be being relinquished by the netfs
- * simultaneously
- * - the object is pinned by the caller holding a refcount on it
- */
-void fscache_withdrawing_object(struct fscache_cache *cache,
- struct fscache_object *object)
-{
- bool enqueue = false;
+ fscache_stat(&fscache_n_cop_drop_object);
+ cache->ops->drop_object(object);
+ fscache_stat_d(&fscache_n_cop_drop_object);
- _enter(",OBJ%x", object->debug_id);
+ /* The parent object wants to know when all it dependents have gone */
+ if (parent) {
+ _debug("release parent OBJ%x {%d}",
+ parent->debug_id, parent->n_children);
- spin_lock(&object->lock);
- if (object->state < FSCACHE_OBJECT_WITHDRAWING) {
- object->state = FSCACHE_OBJECT_WITHDRAWING;
- enqueue = true;
+ spin_lock(&parent->lock);
+ parent->n_children--;
+ if (parent->n_children == 0)
+ fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
+ spin_unlock(&parent->lock);
+ object->parent = NULL;
}
- spin_unlock(&object->lock);
- if (enqueue)
- fscache_enqueue_object(object);
+ /* this just shifts the object release to the work processor */
+ fscache_put_object(object);
+ fscache_stat(&fscache_n_object_dead);
_leave("");
+ return transit_to(OBJECT_DEAD);
}
/*
@@ -771,7 +736,7 @@ static int fscache_get_object(struct fscache_object *object)
}
/*
- * discard a ref on a work item
+ * Discard a ref on an object
*/
static void fscache_put_object(struct fscache_object *object)
{
@@ -780,6 +745,22 @@ static void fscache_put_object(struct fscache_object *object)
fscache_stat_d(&fscache_n_cop_put_object);
}
+/**
+ * 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.
+ */
+void fscache_object_destroy(struct fscache_object *object)
+{
+ fscache_objlist_remove(object);
+
+ /* We can get rid of the cookie now */
+ fscache_cookie_put(object->cookie);
+ object->cookie = NULL;
+}
+EXPORT_SYMBOL(fscache_object_destroy);
+
/*
* enqueue an object for metadata-type processing
*/
@@ -803,7 +784,7 @@ void fscache_enqueue_object(struct fscache_object *object)
/**
* fscache_object_sleep_till_congested - Sleep until object wq is congested
- * @timoutp: Scheduler sleep timeout
+ * @timeoutp: Scheduler sleep timeout
*
* Allow an object handler to sleep until the object workqueue is congested.
*
@@ -831,18 +812,21 @@ bool fscache_object_sleep_till_congested(signed long *timeoutp)
EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested);
/*
- * enqueue the dependents of an object for metadata-type processing
- * - the caller must hold the object's lock
- * - this may cause an already locked object to wind up being processed again
+ * Enqueue the dependents of an object for metadata-type processing.
+ *
+ * If we don't manage to finish the list before the scheduler wants to run
+ * again then return false immediately. We return true if the list was
+ * cleared.
*/
-static void fscache_enqueue_dependents(struct fscache_object *object)
+static bool fscache_enqueue_dependents(struct fscache_object *object, int event)
{
struct fscache_object *dep;
+ bool ret = true;
_enter("{OBJ%x}", object->debug_id);
if (list_empty(&object->dependents))
- return;
+ return true;
spin_lock(&object->lock);
@@ -851,23 +835,23 @@ static void fscache_enqueue_dependents(struct fscache_object *object)
struct fscache_object, dep_link);
list_del_init(&dep->dep_link);
-
- /* sort onto appropriate lists */
- fscache_enqueue_object(dep);
+ fscache_raise_event(dep, event);
fscache_put_object(dep);
- if (!list_empty(&object->dependents))
- cond_resched_lock(&object->lock);
+ if (!list_empty(&object->dependents) && need_resched()) {
+ ret = false;
+ break;
+ }
}
spin_unlock(&object->lock);
+ return ret;
}
/*
* remove an object from whatever queue it's waiting on
- * - the caller must hold object->lock
*/
-void fscache_dequeue_object(struct fscache_object *object)
+static void fscache_dequeue_object(struct fscache_object *object)
{
_enter("{OBJ%x}", object->debug_id);
@@ -886,7 +870,10 @@ void fscache_dequeue_object(struct fscache_object *object)
* @data: The auxiliary data for the object
* @datalen: The size of the auxiliary data
*
- * This function consults the netfs about the coherency state of an object
+ * This function consults the netfs about the coherency state of an object.
+ * The caller must be holding a ref on cookie->n_active (held by
+ * fscache_look_up_object() on behalf of the cache backend during object lookup
+ * and creation).
*/
enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
const void *data, uint16_t datalen)
@@ -927,12 +914,23 @@ EXPORT_SYMBOL(fscache_check_aux);
/*
* Asynchronously invalidate an object.
*/
-static void fscache_invalidate_object(struct fscache_object *object)
+static const struct fscache_state *_fscache_invalidate_object(struct fscache_object *object,
+ int event)
{
struct fscache_operation *op;
struct fscache_cookie *cookie = object->cookie;
- _enter("{OBJ%x}", object->debug_id);
+ _enter("{OBJ%x},%d", object->debug_id, event);
+
+ /* We're going to need the cookie. If the cookie is not available then
+ * retire the object instead.
+ */
+ if (!fscache_use_cookie(object)) {
+ ASSERT(object->cookie->stores.rnode == NULL);
+ set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags);
+ _leave(" [no cookie]");
+ return transit_to(KILL_OBJECT);
+ }
/* Reject any new read/write ops and abort any that are pending. */
fscache_invalidate_writes(cookie);
@@ -941,14 +939,13 @@ static void fscache_invalidate_object(struct fscache_object *object)
/* Now we have to wait for in-progress reads and writes */
op = kzalloc(sizeof(*op), GFP_KERNEL);
- if (!op) {
- fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
- _leave(" [ENOMEM]");
- return;
- }
+ if (!op)
+ goto nomem;
fscache_operation_init(op, object->cache->ops->invalidate_object, NULL);
- op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE);
+ op->flags = FSCACHE_OP_ASYNC |
+ (1 << FSCACHE_OP_EXCLUSIVE) |
+ (1 << FSCACHE_OP_UNUSE_COOKIE);
spin_lock(&cookie->lock);
if (fscache_submit_exclusive_op(object, op) < 0)
@@ -965,13 +962,50 @@ static void fscache_invalidate_object(struct fscache_object *object)
/* We can allow read and write requests to come in once again. They'll
* queue up behind our exclusive invalidation operation.
*/
- fscache_invalidation_complete(cookie);
- _leave("");
- return;
+ if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
+ wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING);
+ _leave(" [ok]");
+ return transit_to(UPDATE_OBJECT);
+
+nomem:
+ clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
+ fscache_unuse_cookie(object);
+ _leave(" [ENOMEM]");
+ return transit_to(KILL_OBJECT);
submit_op_failed:
+ clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
spin_unlock(&cookie->lock);
kfree(op);
- fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
_leave(" [EIO]");
+ return transit_to(KILL_OBJECT);
+}
+
+static const struct fscache_state *fscache_invalidate_object(struct fscache_object *object,
+ int event)
+{
+ const struct fscache_state *s;
+
+ fscache_stat(&fscache_n_invalidates_run);
+ fscache_stat(&fscache_n_cop_invalidate_object);
+ s = _fscache_invalidate_object(object, event);
+ fscache_stat_d(&fscache_n_cop_invalidate_object);
+ return s;
+}
+
+/*
+ * Asynchronously update an object.
+ */
+static const struct fscache_state *fscache_update_object(struct fscache_object *object,
+ int event)
+{
+ _enter("{OBJ%x},%d", object->debug_id, event);
+
+ fscache_stat(&fscache_n_updates_run);
+ fscache_stat(&fscache_n_cop_update_object);
+ object->cache->ops->update_object(object);
+ fscache_stat_d(&fscache_n_cop_update_object);
+
+ _leave("");
+ return transit_to(WAIT_FOR_CMD);
}
diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index 762a9ec4ffa..318071aca21 100644
--- a/fs/fscache/operation.c
+++ b/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
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index ff000e52072..d479ab3c63e 100644
--- a/fs/fscache/page.c
+++ b/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);
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 5dfa0aa216b..a9ff9a36b86 100644
--- a/include/linux/fscache-cache.h
+++ b/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[];
+extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *,
+ struct fscache_cache *);
+extern void fscache_object_destroy(struct fscache_object *);
-#define fscache_object_is_active(obj) \
- (!test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
- (obj)->state >= FSCACHE_OBJECT_AVAILABLE && \
- (obj)->state < FSCACHE_OBJECT_DYING)
+extern void fscache_object_lookup_negative(struct fscache_object *object);
+extern void fscache_obtained_object(struct fscache_object *object);
-#define fscache_object_is_dead(obj) \
- (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
- (obj)->state >= FSCACHE_OBJECT_DYING)
+static inline bool fscache_object_is_live(struct fscache_object *object)
+{
+ return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
+}
-extern void fscache_object_work_func(struct work_struct *work);
+static inline bool fscache_object_is_dying(struct fscache_object *object)
+{
+ return !fscache_object_is_live(object);
+}
-/**
- * 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)
+static inline bool fscache_object_is_available(struct fscache_object *object)
{
- 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;
+ return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
}
-extern void fscache_object_lookup_negative(struct fscache_object *object);
-extern void fscache_obtained_object(struct fscache_object *object);
+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);
+}
-#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_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
*/
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 1133695eb06..f487a4750b7 100644
--- a/include/linux/wait.h
+++ b/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
diff --git a/kernel/wait.c b/kernel/wait.c
index 6698e0c04ea..ce0daa320a2 100644
--- a/kernel/wait.c
+++ b/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);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-04 20:01:31 +0000