Return-Path: linux-nfs-owner@vger.kernel.org Received: from mailhub.sw.ru ([195.214.232.25]:5466 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756341Ab3AOII7 (ORCPT ); Tue, 15 Jan 2013 03:08:59 -0500 Subject: [PATCH 4/4] SUNRPC: move cache_detail->cache_request callback call to cache_read() To: bfields@fieldses.org From: Stanislav Kinsbursky Cc: linux-nfs@vger.kernel.org, Trond.Myklebust@netapp.com, linux-kernel@vger.kernel.org, devel@openvz.org Date: Tue, 15 Jan 2013 11:09:46 +0300 Message-ID: <20130115080946.2996.96945.stgit@localhost.localdomain> In-Reply-To: <20130115080402.2996.74320.stgit@localhost.localdomain> References: <20130115080402.2996.74320.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: function The reason to move cache_request() callback call from sunrpc_cache_pipe_upcall() to cache_read() is that this garantees, that cache access will be done userspace process context (only userspace process have proper root context). This is required for NFSd support in container: svc_export_request() (which is cache_request callback) calls d_path(), which, in turn, traverse dentry up to current->fs->root. Kernel threads always have global root, while container have be in "root jail" - i.e. have it's own nested root. Signed-off-by: Stanislav Kinsbursky --- net/sunrpc/cache.c | 32 ++++++++++++++++++++------------ 1 files changed, 20 insertions(+), 12 deletions(-) diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 901fdca..55f044c 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -750,6 +750,18 @@ struct cache_reader { int offset; /* if non-0, we have a refcnt on next request */ }; +static int cache_request(struct cache_detail *detail, + struct cache_request *crq) +{ + char *bp = crq->buf; + int len = PAGE_SIZE; + + detail->cache_request(detail, crq->item, &bp, &len); + if (len < 0) + return -EAGAIN; + return PAGE_SIZE - len; +} + static ssize_t cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos, struct cache_detail *cd) { @@ -784,6 +796,13 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count, rq->readers++; spin_unlock(&queue_lock); + if (rq->len == 0) { + err = cache_request(cd, rq); + if (err < 0) + goto out; + rq->len = err; + } + if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { err = -EAGAIN; spin_lock(&queue_lock); @@ -1145,8 +1164,6 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h) char *buf; struct cache_request *crq; - char *bp; - int len; if (!cache_listeners_exist(detail)) { warn_no_listener(detail); @@ -1163,19 +1180,10 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h) return -EAGAIN; } - bp = buf; len = PAGE_SIZE; - - detail->cache_request(detail, h, &bp, &len); - - if (len < 0) { - kfree(buf); - kfree(crq); - return -EAGAIN; - } crq->q.reader = 0; crq->item = cache_get(h); crq->buf = buf; - crq->len = PAGE_SIZE - len; + crq->len = 0; crq->readers = 0; spin_lock(&queue_lock); list_add_tail(&crq->q.list, &detail->queue);