diff options
author | James Morris <jmorris@macbook.(none)> | 2009-12-03 12:03:40 +0530 |
---|---|---|
committer | James Morris <jmorris@macbook.(none)> | 2009-12-03 12:03:40 +0530 |
commit | c84d6efd363a3948eb32ec40d46bab6338580454 (patch) | |
tree | 3ba7ac46e6626fe8ac843834588609eb6ccee5c6 /fs/cachefiles/namei.c | |
parent | 7539cf4b92be4aecc573ea962135f246a7a33401 (diff) | |
parent | 22763c5cf3690a681551162c15d34d935308c8d7 (diff) |
Merge branch 'master' into next
Diffstat (limited to 'fs/cachefiles/namei.c')
-rw-r--r-- | fs/cachefiles/namei.c | 187 |
1 files changed, 142 insertions, 45 deletions
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 4ce818ae39e..14ac4806e29 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -21,17 +21,81 @@ #include <linux/security.h> #include "internal.h" -static int cachefiles_wait_bit(void *flags) +#define CACHEFILES_KEYBUF_SIZE 512 + +/* + * dump debugging info about an object + */ +static noinline +void __cachefiles_printk_object(struct cachefiles_object *object, + const char *prefix, + u8 *keybuf) { - schedule(); - return 0; + struct fscache_cookie *cookie; + unsigned keylen, loop; + + printk(KERN_ERR "%sobject: OBJ%x\n", + prefix, object->fscache.debug_id); + printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n", + prefix, fscache_object_states[object->fscache.state], + object->fscache.flags, object->fscache.work.flags, + object->fscache.events, + object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK); + printk(KERN_ERR "%sops=%u inp=%u exc=%u\n", + prefix, object->fscache.n_ops, object->fscache.n_in_progress, + object->fscache.n_exclusive); + printk(KERN_ERR "%sparent=%p\n", + prefix, object->fscache.parent); + + spin_lock(&object->fscache.lock); + cookie = object->fscache.cookie; + if (cookie) { + printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n", + prefix, + object->fscache.cookie, + object->fscache.cookie->parent, + object->fscache.cookie->netfs_data, + object->fscache.cookie->flags); + if (keybuf) + keylen = cookie->def->get_key(cookie->netfs_data, keybuf, + CACHEFILES_KEYBUF_SIZE); + else + keylen = 0; + } else { + printk(KERN_ERR "%scookie=NULL\n", prefix); + keylen = 0; + } + spin_unlock(&object->fscache.lock); + + if (keylen) { + printk(KERN_ERR "%skey=[%u] '", prefix, keylen); + for (loop = 0; loop < keylen; loop++) + printk("%02x", keybuf[loop]); + printk("'\n"); + } +} + +/* + * dump debugging info about a pair of objects + */ +static noinline void cachefiles_printk_object(struct cachefiles_object *object, + struct cachefiles_object *xobject) +{ + u8 *keybuf; + + keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO); + if (object) + __cachefiles_printk_object(object, "", keybuf); + if (xobject) + __cachefiles_printk_object(xobject, "x", keybuf); + kfree(keybuf); } /* * 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; @@ -42,8 +106,11 @@ static void cachefiles_mark_object_active(struct cachefiles_cache *cache, try_again: write_lock(&cache->active_lock); - if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) + if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { + printk(KERN_ERR "CacheFiles: Error: Object already active\n"); + cachefiles_printk_object(object, NULL); BUG(); + } dentry = object->dentry; _p = &cache->active_nodes.rb_node; @@ -66,8 +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 */ @@ -76,44 +143,70 @@ wait_for_old_object: printk(KERN_ERR "\n"); printk(KERN_ERR "CacheFiles: Error:" " Unexpected object collision\n"); - printk(KERN_ERR "xobject: OBJ%x\n", - xobject->fscache.debug_id); - printk(KERN_ERR "xobjstate=%s\n", - fscache_object_states[xobject->fscache.state]); - printk(KERN_ERR "xobjflags=%lx\n", xobject->fscache.flags); - printk(KERN_ERR "xobjevent=%lx [%lx]\n", - xobject->fscache.events, xobject->fscache.event_mask); - printk(KERN_ERR "xops=%u inp=%u exc=%u\n", - xobject->fscache.n_ops, xobject->fscache.n_in_progress, - xobject->fscache.n_exclusive); - printk(KERN_ERR "xcookie=%p [pr=%p nd=%p fl=%lx]\n", - xobject->fscache.cookie, - xobject->fscache.cookie->parent, - xobject->fscache.cookie->netfs_data, - xobject->fscache.cookie->flags); - printk(KERN_ERR "xparent=%p\n", - xobject->fscache.parent); - printk(KERN_ERR "object: OBJ%x\n", - object->fscache.debug_id); - printk(KERN_ERR "cookie=%p [pr=%p nd=%p fl=%lx]\n", - object->fscache.cookie, - object->fscache.cookie->parent, - object->fscache.cookie->netfs_data, - object->fscache.cookie->flags); - printk(KERN_ERR "parent=%p\n", - object->fscache.parent); + cachefiles_printk_object(object, xobject); BUG(); } 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; } /* @@ -254,7 +347,7 @@ int cachefiles_delete_object(struct cachefiles_cache *cache, dir = dget_parent(object->dentry); - mutex_lock(&dir->d_inode->i_mutex); + mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); ret = cachefiles_bury_object(cache, dir, object->dentry); dput(dir); @@ -307,7 +400,7 @@ lookup_again: /* search the current directory for the element name */ _debug("lookup '%s'", name); - mutex_lock(&dir->d_inode->i_mutex); + mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); start = jiffies; next = lookup_one_len(name, dir, nlen); @@ -418,12 +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) { @@ -467,6 +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); @@ -474,7 +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; @@ -495,9 +595,6 @@ error: error_out2: dput(dir); error_out: - if (ret == -ENOSPC) - ret = -ENOBUFS; - _leave(" = error %d", -ret); return ret; } |