diff options
| -rw-r--r-- | fs/cachefiles/interface.c | 11 | ||||
| -rw-r--r-- | fs/cachefiles/xattr.c | 6 | ||||
| -rw-r--r-- | fs/fscache/cookie.c | 80 | ||||
| -rw-r--r-- | fs/fscache/fsdef.c | 1 | ||||
| -rw-r--r-- | fs/fscache/internal.h | 3 | ||||
| -rw-r--r-- | fs/fscache/main.c | 11 | ||||
| -rw-r--r-- | fs/fscache/netfs.c | 1 | ||||
| -rw-r--r-- | fs/fscache/object-list.c | 93 | ||||
| -rw-r--r-- | fs/fscache/object.c | 188 | ||||
| -rw-r--r-- | fs/fscache/operation.c | 12 | ||||
| -rw-r--r-- | fs/fscache/page.c | 26 | ||||
| -rw-r--r-- | include/linux/fscache-cache.h | 55 |
12 files changed, 230 insertions, 257 deletions
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index 3d763217faf3..eeb3f7d0e1a7 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -212,20 +212,29 @@ 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 +272,7 @@ static void cachefiles_drop_object(struct fscache_object *_object) #endif /* delete retired objects */ - if (test_bit(FSCACHE_OBJECT_RETIRE, &object->fscache.flags) && + 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/xattr.c b/fs/cachefiles/xattr.c index 73b46288b54b..2476e5162609 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/cookie.c b/fs/fscache/cookie.c index eee436646989..0e91a3c9fdb2 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 @@ -467,7 +471,6 @@ EXPORT_SYMBOL(__fscache_update_cookie); */ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) { - struct fscache_cache *cache; struct fscache_object *object; fscache_stat(&fscache_n_relinquishes); @@ -480,8 +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", @@ -489,62 +495,28 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) BUG(); } - /* wait for the cookie to finish being instantiated (or to fail) */ - if (test_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) { - fscache_stat(&fscache_n_relinquishes_waitcrt); - wait_on_bit(&cookie->flags, FSCACHE_COOKIE_CREATING, - fscache_wait_bit, TASK_UNINTERRUPTIBLE); - } + /* No further netfs-accessing operations on this cookie permitted */ + set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags); + if (retire) + set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags); -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; - if (retire) - set_bit(FSCACHE_OBJECT_RETIRE, &object->flags); + hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) { fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL); - spin_unlock(&object->lock); - - if (atomic_dec_and_test(&cookie->usage)) - /* the cookie refcount shouldn't be reduced to 0 yet */ - BUG(); } + 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); @@ -552,7 +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 f5b4baee7352..10a2ade0bdf8 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 3322d3c42ba8..12d505bedb5c 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -93,6 +93,7 @@ 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 @@ -106,8 +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 /* diff --git a/fs/fscache/main.c b/fs/fscache/main.c index f9d856773f79..7c27907e650c 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 e028b8eb1c40..b1bb6117473a 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 4a386b080e03..e1959efad64f 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 @@ -166,10 +162,9 @@ 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) { @@ -216,8 +211,9 @@ 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(fscache_object_is_active(obj) || obj->n_ops != 0 || @@ -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 8f17debd7979..86d75a60b20c 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -30,7 +30,6 @@ static const struct fscache_state *fscache_look_up_object(struct fscache_object 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); -static const struct fscache_state *fscache_detach_from_cookie(struct fscache_object *, int); #define __STATE_NAME(n) fscache_osm_##n #define STATE(n) (&__STATE_NAME(n)) @@ -92,7 +91,6 @@ 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(DETACH_FROM_COOKIE, "DTCH", fscache_detach_from_cookie); static WORK_STATE(OBJECT_DEAD, "DEAD", (void*)2UL); static WAIT_STATE(WAIT_FOR_INIT, "?INI", @@ -156,8 +154,8 @@ 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); @@ -332,22 +330,10 @@ EXPORT_SYMBOL(fscache_object_init); static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *object, int event) { - struct fscache_cookie *cookie; - _enter("{OBJ%x},%d", object->debug_id, event); object->oob_event_mask = 0; - clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); - fscache_dequeue_object(object); - - spin_lock(&object->lock); - cookie = object->cookie; - clear_bit_unlock(FSCACHE_COOKIE_CREATING, &cookie->flags); - spin_unlock(&object->lock); - - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); - return transit_to(KILL_OBJECT); } @@ -357,8 +343,6 @@ static const struct fscache_state *fscache_abort_initialisation(struct fscache_o * 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 const struct fscache_state *fscache_initialise_object(struct fscache_object *object, int event) @@ -373,14 +357,14 @@ static const struct fscache_state *fscache_initialise_object(struct fscache_obje parent = object->parent; if (!parent) { _leave(" [no parent]"); - return transit_to(DETACH_FROM_COOKIE); + return transit_to(DROP_OBJECT); } - _debug("parent %s", parent->state->name); + _debug("parent: %s of:%lx", parent->state->name, parent->flags); if (fscache_object_is_dying(parent)) { _leave(" [bad parent]"); - return transit_to(DETACH_FROM_COOKIE); + return transit_to(DROP_OBJECT); } if (fscache_object_is_available(parent)) { @@ -402,7 +386,7 @@ static const struct fscache_state *fscache_initialise_object(struct fscache_obje spin_unlock(&parent->lock); if (!success) { _leave(" [grab failed]"); - return transit_to(DETACH_FROM_COOKIE); + return transit_to(DROP_OBJECT); } /* fscache_acquire_non_index_cookie() uses this @@ -438,8 +422,6 @@ static const struct fscache_state *fscache_parent_ready(struct fscache_object *o * 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 const struct fscache_state *fscache_look_up_object(struct fscache_object *object, int event) @@ -460,22 +442,21 @@ static const struct fscache_state *fscache_look_up_object(struct fscache_object ASSERT(fscache_object_is_available(parent)); if (fscache_object_is_dying(parent) || - test_bit(FSCACHE_IOERROR, &object->cache->flags)) { + 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 @@ -557,11 +538,6 @@ void fscache_obtained_object(struct fscache_object *object) } set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags); - - /* Permit __fscache_relinquish_cookie() to proceed */ - clear_bit_unlock(FSCACHE_COOKIE_CREATING, &cookie->flags); - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); - _leave(""); } EXPORT_SYMBOL(fscache_obtained_object); @@ -572,16 +548,12 @@ EXPORT_SYMBOL(fscache_obtained_object); static const struct fscache_state *fscache_object_available(struct fscache_object *object, int event) { - struct fscache_cookie *cookie = object->cookie; - _enter("{OBJ%x},%d", object->debug_id, event); object->oob_table = fscache_osm_run_oob; spin_lock(&object->lock); - ASSERTIF(cookie, !test_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)); - fscache_done_parent_op(object); if (object->n_in_progress == 0) { if (object->n_ops > 0) { @@ -624,7 +596,6 @@ static const struct fscache_state *fscache_lookup_failure(struct fscache_object int event) { struct fscache_cookie *cookie; - bool wake_looking_up = false; _enter("{OBJ%x},%d", object->debug_id, event); @@ -634,19 +605,10 @@ static const struct fscache_state *fscache_lookup_failure(struct fscache_object object->cache->ops->lookup_complete(object); fscache_stat_d(&fscache_n_cop_lookup_complete); - spin_lock(&object->lock); cookie = object->cookie; set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); - if (cookie) { - if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) - wake_looking_up = true; - clear_bit_unlock(FSCACHE_COOKIE_CREATING, &cookie->flags); - } - spin_unlock(&object->lock); - - if (wake_looking_up) + if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); fscache_done_parent_op(object); return transit_to(KILL_OBJECT); @@ -662,21 +624,20 @@ static const struct fscache_state *fscache_kill_object(struct fscache_object *ob _enter("{OBJ%x,%d,%d},%d", object->debug_id, object->n_ops, object->n_children, event); - object->oob_event_mask = 0; - - spin_lock(&object->lock); clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); - spin_unlock(&object->lock); + object->oob_event_mask = 0; if (list_empty(&object->dependents) && object->n_ops == 0 && object->n_children == 0) - return object->cookie ? - transit_to(DETACH_FROM_COOKIE) : transit_to(DROP_OBJECT); + return transit_to(DROP_OBJECT); - spin_lock(&object->lock); - fscache_start_operations(object); - spin_unlock(&object->lock); + 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); + } if (!list_empty(&object->dependents)) return transit_to(KILL_DEPENDENTS); @@ -698,64 +659,32 @@ static const struct fscache_state *fscache_kill_dependents(struct fscache_object } /* - * withdraw an object from active service - */ -static const struct fscache_state *fscache_detach_from_cookie(struct fscache_object *object, - int event) -{ - struct fscache_cookie *cookie; - bool detached = false, awaken = false; - - _enter("{OBJ%x},%d", object->debug_id, 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); - - spin_lock(&cookie->lock); - spin_lock(&object->lock); - - if (object->cookie == cookie) { - hlist_del_init(&object->cookie_link); - object->cookie = NULL; - if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, - &cookie->flags)) - awaken = true; - detached = true; - } - spin_unlock(&cookie->lock); - fscache_cookie_put(cookie); - if (detached) - fscache_cookie_put(cookie); - } - - spin_unlock(&object->lock); - - if (awaken) - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING); - - fscache_stat(&fscache_n_object_dead); - _leave(""); - return transit_to(DROP_OBJECT); -} - -/* * Drop an object's attachments */ static const struct fscache_state *fscache_drop_object(struct fscache_object *object, int event) { struct fscache_object *parent = object->parent; + struct fscache_cookie *cookie = object->cookie; struct fscache_cache *cache = object->cache; + bool awaken = false; _enter("{OBJ%x,%d},%d", object->debug_id, object->n_children, event); - ASSERTCMP(object->cookie, ==, NULL); - ASSERT(hlist_unhashed(&object->cookie_link)); + ASSERT(cookie != NULL); + ASSERT(!hlist_unhashed(&object->cookie_link)); + + /* 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 (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. @@ -816,6 +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 */ @@ -925,7 +870,10 @@ static 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) @@ -974,6 +922,15 @@ static const struct fscache_state *_fscache_invalidate_object(struct fscache_obj _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); @@ -982,14 +939,13 @@ static const struct fscache_state *_fscache_invalidate_object(struct fscache_obj /* Now we have to wait for in-progress reads and writes */ op = kzalloc(sizeof(*op), GFP_KERNEL); - if (!op) { - clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); - _leave(" [ENOMEM]"); - return transit_to(KILL_OBJECT); - } + 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) @@ -1011,6 +967,12 @@ static const struct fscache_state *_fscache_invalidate_object(struct fscache_obj _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); diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c index 4da211b21ddf..6935901bce38 100644 --- a/fs/fscache/operation.c +++ b/fs/fscache/operation.c @@ -424,14 +424,10 @@ 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 b4e4b424160a..780bac6ffde5 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -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); } @@ -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; @@ -394,7 +400,8 @@ 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; @@ -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); @@ -522,7 +530,7 @@ 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; @@ -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); @@ -631,7 +640,7 @@ 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; @@ -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); @@ -876,7 +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) @@ -922,6 +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; @@ -948,6 +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 9ff516b1b9a0..d32f70611a00 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; @@ -314,6 +315,7 @@ 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 */ @@ -326,11 +328,11 @@ 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_UNAVAILABLE 3 /* T if cookie is unavailable (error, etc) */ -#define FSCACHE_COOKIE_WAITING_ON_READS 4 /* T if cookie is waiting on reads */ -#define FSCACHE_COOKIE_INVALIDATING 5 /* 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; @@ -392,10 +394,9 @@ 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_RETIRE 3 /* T if object should be retired */ -#define FSCACHE_OBJECT_IS_LIVE 4 /* T if object is not withdrawn or relinquished */ -#define FSCACHE_OBJECT_IS_LOOKED_UP 5 /* T if object has been looked up */ -#define FSCACHE_OBJECT_IS_AVAILABLE 6 /* T if object has become active */ +#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 */ @@ -415,16 +416,11 @@ struct fscache_object { extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *, struct fscache_cache *); +extern void fscache_object_destroy(struct fscache_object *); extern void fscache_object_lookup_negative(struct fscache_object *object); extern void fscache_obtained_object(struct fscache_object *object); -#ifdef CONFIG_FSCACHE_OBJECT_LIST -extern void fscache_object_destroy(struct fscache_object *object); -#else -#define fscache_object_destroy(object) do {} while(0) -#endif - static inline bool fscache_object_is_live(struct fscache_object *object) { return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); @@ -512,6 +508,33 @@ 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 */ |