Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:23215 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756092Ab2BHVSX (ORCPT ); Wed, 8 Feb 2012 16:18:23 -0500 From: David Howells Subject: [PATCH 09/17] CacheFiles: Implement invalidation To: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-cachefs@redhat.com, linux-nfs@vger.kernel.org Date: Wed, 08 Feb 2012 21:18:13 +0000 Message-ID: <20120208211813.15607.14339.stgit@warthog.procyon.org.uk> In-Reply-To: <20120208211640.15607.58537.stgit@warthog.procyon.org.uk> References: <20120208211640.15607.58537.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Implement invalidation for CacheFiles. This is in two parts: (1) Provide an invalidation method (which just truncates the backing file). (2) Abort attempts to copy anything read from the backing file whilst invalidation is in progress. Question: CacheFiles uses truncation in a couple of places. It has been using notify_change() rather than sys_truncate() or something similar. This means it bypasses a bunch of checks and suchlike that it possibly should be making (security, file locking, lease breaking, vfsmount write). Should it be using vfs_truncate() as added by a preceding patch or should it use notify_write() and assume that anyone poking around in the cache files on disk gets everything they deserve? Signed-off-by: David Howells --- fs/cachefiles/interface.c | 49 +++++++++++++++++++++++++++++++++++++++++++++ fs/cachefiles/rdwr.c | 5 ++++- 2 files changed, 53 insertions(+), 1 deletions(-) diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index 9bff0f8..7a9d574 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -441,6 +441,54 @@ truncate_failed: } /* + * Invalidate an object + */ +static void cachefiles_invalidate_object(struct fscache_operation *op) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + const struct cred *saved_cred; + struct path path; + uint64_t ni_size; + int ret; + + object = container_of(op->object, struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + op->object->cookie->def->get_attr(op->object->cookie->netfs_data, + &ni_size); + + _enter("{OBJ%x},[%llu]", + op->object->debug_id, (unsigned long long)ni_size); + + if (object->backer) { + ASSERT(S_ISREG(object->backer->d_inode->i_mode)); + + fscache_set_store_limit(&object->fscache, ni_size); + + path.dentry = object->backer; + path.mnt = cache->mnt; + + cachefiles_begin_secure(cache, &saved_cred); + ret = vfs_truncate(&path, 0); + if (ret == 0) + ret = vfs_truncate(&path, ni_size); + cachefiles_end_secure(cache, saved_cred); + + if (ret != 0) { + fscache_set_store_limit(&object->fscache, 0); + if (ret == -EIO) + cachefiles_io_error_obj(object, + "Invalidate failed"); + } + } + + fscache_op_complete(op); + _leave(""); +} + +/* * dissociate a cache from all the pages it was backing */ static void cachefiles_dissociate_pages(struct fscache_cache *cache) @@ -455,6 +503,7 @@ const struct fscache_cache_ops cachefiles_cache_ops = { .lookup_complete = cachefiles_lookup_complete, .grab_object = cachefiles_grab_object, .update_object = cachefiles_update_object, + .invalidate_object = cachefiles_invalidate_object, .drop_object = cachefiles_drop_object, .put_object = cachefiles_put_object, .sync_cache = cachefiles_sync_cache, diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index 31cda81..f437e97 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -174,7 +174,10 @@ static void cachefiles_read_copier(struct fscache_operation *_op) _debug("- copy {%lu}", monitor->back_page->index); recheck: - if (PageUptodate(monitor->back_page)) { + if (test_bit(FSCACHE_COOKIE_INVALIDATING, + &object->fscache.cookie->flags)) { + error = -ESTALE; + } else if (PageUptodate(monitor->back_page)) { copy_highpage(monitor->netfs_page, monitor->back_page); fscache_mark_page_cached(monitor->op, monitor->netfs_page);