#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/security.h>
+#include <linux/slab.h>
#include "internal.h"
-static int cachefiles_wait_bit(void *flags)
-{
- schedule();
- return 0;
-}
-
#define CACHEFILES_KEYBUF_SIZE 512
/*
}
/*
+ * mark the owner of a dentry, if there is one, to indicate that that dentry
+ * has been preemptively deleted
+ * - the caller must hold the i_mutex on the dentry's parent as required to
+ * call vfs_unlink(), vfs_rmdir() or vfs_rename()
+ */
+static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
+ struct dentry *dentry)
+{
+ struct cachefiles_object *object;
+ struct rb_node *p;
+
+ _enter(",'%*.*s'",
+ dentry->d_name.len, dentry->d_name.len, dentry->d_name.name);
+
+ write_lock(&cache->active_lock);
+
+ p = cache->active_nodes.rb_node;
+ while (p) {
+ object = rb_entry(p, struct cachefiles_object, active_node);
+ if (object->dentry > dentry)
+ p = p->rb_left;
+ else if (object->dentry < dentry)
+ p = p->rb_right;
+ else
+ goto found_dentry;
+ }
+
+ write_unlock(&cache->active_lock);
+ _leave(" [no owner]");
+ return;
+
+ /* found the dentry for */
+found_dentry:
+ kdebug("preemptive burial: OBJ%x [%s] %p",
+ object->fscache.debug_id,
+ fscache_object_states[object->fscache.state],
+ dentry);
+
+ if (object->fscache.state < FSCACHE_OBJECT_DYING) {
+ printk(KERN_ERR "\n");
+ printk(KERN_ERR "CacheFiles: Error:"
+ " Can't preemptively bury live object\n");
+ cachefiles_printk_object(object, NULL);
+ } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
+ printk(KERN_ERR "CacheFiles: Error:"
+ " Object already preemptively buried\n");
+ }
+
+ write_unlock(&cache->active_lock);
+ _leave(" [owner marked]");
+}
+
+/*
* 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;
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 */
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;
}
/*
*/
static int cachefiles_bury_object(struct cachefiles_cache *cache,
struct dentry *dir,
- struct dentry *rep)
+ struct dentry *rep,
+ bool preemptive)
{
struct dentry *grave, *trap;
char nbuffer[8 + 8 + 1];
dir->d_name.len, dir->d_name.len, dir->d_name.name,
rep->d_name.len, rep->d_name.len, rep->d_name.name);
+ _debug("remove %p from %p", rep, dir);
+
/* non-directories can just be unlinked */
if (!S_ISDIR(rep->d_inode->i_mode)) {
_debug("unlink stale object");
ret = vfs_unlink(dir->d_inode, rep);
+ if (preemptive)
+ cachefiles_mark_object_buried(cache, rep);
+
mutex_unlock(&dir->d_inode->i_mutex);
if (ret == -EIO)
if (ret != 0 && ret != -ENOMEM)
cachefiles_io_error(cache, "Rename failed with error %d", ret);
+ if (preemptive)
+ cachefiles_mark_object_buried(cache, rep);
+
unlock_rename(cache->graveyard, dir);
dput(grave);
_leave(" = 0");
struct dentry *dir;
int ret;
- _enter(",{%p}", object->dentry);
+ _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
ASSERT(object->dentry);
ASSERT(object->dentry->d_inode);
dir = dget_parent(object->dentry);
mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
- ret = cachefiles_bury_object(cache, dir, object->dentry);
+
+ if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
+ /* object allocation for the same key preemptively deleted this
+ * object's file so that it could create its own file */
+ _debug("object preemptively buried");
+ mutex_unlock(&dir->d_inode->i_mutex);
+ ret = 0;
+ } else {
+ /* we need to check that our parent is _still_ our parent - it
+ * may have been renamed */
+ if (dir == object->dentry->d_parent) {
+ ret = cachefiles_bury_object(cache, dir,
+ object->dentry, false);
+ } else {
+ /* it got moved, presumably by cachefilesd culling it,
+ * so it's no longer in the key path and we can ignore
+ * it */
+ mutex_unlock(&dir->d_inode->i_mutex);
+ ret = 0;
+ }
+ }
dput(dir);
_leave(" = %d", ret);
const char *name;
int ret, nlen;
- _enter("{%p},,%s,", parent->dentry, key);
+ _enter("OBJ%x{%p},OBJ%x,%s,",
+ parent->fscache.debug_id, parent->dentry,
+ object->fscache.debug_id, key);
cache = container_of(parent->fscache.cache,
struct cachefiles_cache, cache);
* mutex) */
object->dentry = NULL;
- ret = cachefiles_bury_object(cache, dir, next);
+ ret = cachefiles_bury_object(cache, dir, next, true);
dput(next);
next = NULL;
}
/* 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) {
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);
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;
error_out2:
dput(dir);
error_out:
- if (ret == -ENOSPC)
- ret = -ENOBUFS;
-
_leave(" = error %d", -ret);
return ret;
}
/* actually remove the victim (drops the dir mutex) */
_debug("bury");
- ret = cachefiles_bury_object(cache, dir, victim);
+ ret = cachefiles_bury_object(cache, dir, victim, false);
if (ret < 0)
goto error;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff