diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/cachefiles/internal.h | 1 | ||||
| -rw-r--r-- | fs/cachefiles/namei.c | 98 |
2 files changed, 87 insertions, 12 deletions
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index f7c255f..a8cd821 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -34,6 +34,7 @@ struct cachefiles_object { loff_t i_size; /* object size */ unsigned long flags; #define CACHEFILES_OBJECT_ACTIVE 0 /* T if marked active */ +#define CACHEFILES_OBJECT_BURIED 1 /* T if preemptively buried */ atomic_t usage; /* object usage count */ uint8_t type; /* object type */ uint8_t new; /* T if object new */ diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index d5db84a..f4a7840 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -93,6 +93,59 @@ static noinline void cachefiles_printk_object(struct cachefiles_object *object, } /* + * 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 int cachefiles_mark_object_active(struct cachefiles_cache *cache, @@ -219,7 +272,8 @@ requeue: */ 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]; @@ -229,11 +283,16 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, 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) @@ -325,6 +384,9 @@ try_again: 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"); @@ -340,7 +402,7 @@ int cachefiles_delete_object(struct cachefiles_cache *cache, 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); @@ -350,15 +412,25 @@ int cachefiles_delete_object(struct cachefiles_cache *cache, mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); - /* 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); - } else { - /* it got moved, presumably by cachefilesd culling it, so it's - * no longer in the key path and we can ignore it */ + 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); @@ -381,7 +453,9 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 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); @@ -509,7 +583,7 @@ lookup_again: * mutex) */ object->dentry = NULL; - ret = cachefiles_bury_object(cache, dir, next); + ret = cachefiles_bury_object(cache, dir, next, true); dput(next); next = NULL; @@ -828,7 +902,7 @@ int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, /* 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; |