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-rw-r--r--Documentation/filesystems/caching/fscache.txt1
-rw-r--r--fs/cachefiles/interface.c6
-rw-r--r--fs/cachefiles/namei.c87
-rw-r--r--fs/fscache/internal.h1
-rw-r--r--fs/fscache/object.c10
-rw-r--r--fs/fscache/stats.c4
-rw-r--r--include/linux/fscache-cache.h6
7 files changed, 90 insertions, 25 deletions
diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt
index 3c23411..a91e2e2 100644
--- a/Documentation/filesystems/caching/fscache.txt
+++ b/Documentation/filesystems/caching/fscache.txt
@@ -235,6 +235,7 @@ proc files.
neg=N Number of negative lookups made
pos=N Number of positive lookups made
crt=N Number of objects created by lookup
+ tmo=N Number of lookups timed out and requeued
Updates n=N Number of update cookie requests seen
nul=N Number of upd reqs given a NULL parent
run=N Number of upd reqs granted CPU time
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 8e67abf..9d3c426 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -114,8 +114,9 @@ nomem_lookup_data:
/*
* attempt to look up the nominated node in this cache
+ * - return -ETIMEDOUT to be scheduled again
*/
-static void cachefiles_lookup_object(struct fscache_object *_object)
+static int cachefiles_lookup_object(struct fscache_object *_object)
{
struct cachefiles_lookup_data *lookup_data;
struct cachefiles_object *parent, *object;
@@ -145,13 +146,14 @@ static void cachefiles_lookup_object(struct fscache_object *_object)
object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
cachefiles_attr_changed(&object->fscache);
- if (ret < 0) {
+ if (ret < 0 && ret != -ETIMEDOUT) {
printk(KERN_WARNING "CacheFiles: Lookup failed error %d\n",
ret);
fscache_object_lookup_error(&object->fscache);
}
_leave(" [%d]", ret);
+ return ret;
}
/*
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 00a0cda..14ac480 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -21,12 +21,6 @@
#include <linux/security.h>
#include "internal.h"
-static int cachefiles_wait_bit(void *flags)
-{
- schedule();
- return 0;
-}
-
#define CACHEFILES_KEYBUF_SIZE 512
/*
@@ -100,8 +94,8 @@ static noinline void cachefiles_printk_object(struct cachefiles_object *object,
/*
* record the fact that an object is now active
*/
-static void cachefiles_mark_object_active(struct cachefiles_cache *cache,
- struct cachefiles_object *object)
+static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
+ struct cachefiles_object *object)
{
struct cachefiles_object *xobject;
struct rb_node **_p, *_parent = NULL;
@@ -139,8 +133,8 @@ try_again:
rb_insert_color(&object->active_node, &cache->active_nodes);
write_unlock(&cache->active_lock);
- _leave("");
- return;
+ _leave(" = 0");
+ return 0;
/* an old object from a previous incarnation is hogging the slot - we
* need to wait for it to be destroyed */
@@ -155,13 +149,64 @@ wait_for_old_object:
atomic_inc(&xobject->usage);
write_unlock(&cache->active_lock);
- _debug(">>> wait");
- wait_on_bit(&xobject->flags, CACHEFILES_OBJECT_ACTIVE,
- cachefiles_wait_bit, TASK_UNINTERRUPTIBLE);
- _debug("<<< waited");
+ if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
+ wait_queue_head_t *wq;
+
+ signed long timeout = 60 * HZ;
+ wait_queue_t wait;
+ bool requeue;
+
+ /* if the object we're waiting for is queued for processing,
+ * then just put ourselves on the queue behind it */
+ if (slow_work_is_queued(&xobject->fscache.work)) {
+ _debug("queue OBJ%x behind OBJ%x immediately",
+ object->fscache.debug_id,
+ xobject->fscache.debug_id);
+ goto requeue;
+ }
+
+ /* otherwise we sleep until either the object we're waiting for
+ * is done, or the slow-work facility wants the thread back to
+ * do other work */
+ wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
+ init_wait(&wait);
+ requeue = false;
+ do {
+ prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
+ if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
+ break;
+ requeue = slow_work_sleep_till_thread_needed(
+ &object->fscache.work, &timeout);
+ } while (timeout > 0 && !requeue);
+ finish_wait(wq, &wait);
+
+ if (requeue &&
+ test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
+ _debug("queue OBJ%x behind OBJ%x after wait",
+ object->fscache.debug_id,
+ xobject->fscache.debug_id);
+ goto requeue;
+ }
+
+ if (timeout <= 0) {
+ printk(KERN_ERR "\n");
+ printk(KERN_ERR "CacheFiles: Error: Overlong"
+ " wait for old active object to go away\n");
+ cachefiles_printk_object(object, xobject);
+ goto requeue;
+ }
+ }
+
+ ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags));
cache->cache.ops->put_object(&xobject->fscache);
goto try_again;
+
+requeue:
+ clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
+ cache->cache.ops->put_object(&xobject->fscache);
+ _leave(" = -ETIMEDOUT");
+ return -ETIMEDOUT;
}
/*
@@ -466,12 +511,15 @@ lookup_again:
}
/* note that we're now using this object */
- cachefiles_mark_object_active(cache, object);
+ ret = cachefiles_mark_object_active(cache, object);
mutex_unlock(&dir->d_inode->i_mutex);
dput(dir);
dir = NULL;
+ if (ret == -ETIMEDOUT)
+ goto mark_active_timed_out;
+
_debug("=== OBTAINED_OBJECT ===");
if (object->new) {
@@ -515,6 +563,10 @@ create_error:
cachefiles_io_error(cache, "Create/mkdir failed");
goto error;
+mark_active_timed_out:
+ _debug("mark active timed out");
+ goto release_dentry;
+
check_error:
_debug("check error %d", ret);
write_lock(&cache->active_lock);
@@ -522,7 +574,7 @@ check_error:
clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
write_unlock(&cache->active_lock);
-
+release_dentry:
dput(object->dentry);
object->dentry = NULL;
goto error_out;
@@ -543,9 +595,6 @@ error:
error_out2:
dput(dir);
error_out:
- if (ret == -ENOSPC)
- ret = -ENOBUFS;
-
_leave(" = error %d", -ret);
return ret;
}
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index 5b49a37..0ca2566 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -215,6 +215,7 @@ extern atomic_t fscache_n_object_no_alloc;
extern atomic_t fscache_n_object_lookups;
extern atomic_t fscache_n_object_lookups_negative;
extern atomic_t fscache_n_object_lookups_positive;
+extern atomic_t fscache_n_object_lookups_timed_out;
extern atomic_t fscache_n_object_created;
extern atomic_t fscache_n_object_avail;
extern atomic_t fscache_n_object_dead;
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index f3f952c..e513ac5 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -468,6 +468,7 @@ static void fscache_lookup_object(struct fscache_object *object)
{
struct fscache_cookie *cookie = object->cookie;
struct fscache_object *parent;
+ int ret;
_enter("");
@@ -493,12 +494,19 @@ static void fscache_lookup_object(struct fscache_object *object)
fscache_stat(&fscache_n_object_lookups);
fscache_stat(&fscache_n_cop_lookup_object);
- object->cache->ops->lookup_object(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);
+ 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("");
}
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
index 05f77ca..46435f3a 100644
--- a/fs/fscache/stats.c
+++ b/fs/fscache/stats.c
@@ -98,6 +98,7 @@ atomic_t fscache_n_object_no_alloc;
atomic_t fscache_n_object_lookups;
atomic_t fscache_n_object_lookups_negative;
atomic_t fscache_n_object_lookups_positive;
+atomic_t fscache_n_object_lookups_timed_out;
atomic_t fscache_n_object_created;
atomic_t fscache_n_object_avail;
atomic_t fscache_n_object_dead;
@@ -160,10 +161,11 @@ static int fscache_stats_show(struct seq_file *m, void *v)
atomic_read(&fscache_n_acquires_nobufs),
atomic_read(&fscache_n_acquires_oom));
- seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u\n",
+ seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u tmo=%u\n",
atomic_read(&fscache_n_object_lookups),
atomic_read(&fscache_n_object_lookups_negative),
atomic_read(&fscache_n_object_lookups_positive),
+ atomic_read(&fscache_n_object_lookups_timed_out),
atomic_read(&fscache_n_object_created));
seq_printf(m, "Updates: n=%u nul=%u run=%u\n",
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 5db5000..7be0c6f 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -234,8 +234,10 @@ struct fscache_cache_ops {
struct fscache_object *(*alloc_object)(struct fscache_cache *cache,
struct fscache_cookie *cookie);
- /* look up the object for a cookie */
- void (*lookup_object)(struct fscache_object *object);
+ /* look up the object for a cookie
+ * - return -ETIMEDOUT to be requeued
+ */
+ int (*lookup_object)(struct fscache_object *object);
/* finished looking up */
void (*lookup_complete)(struct fscache_object *object);
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