Return-Path: Received: from mail-it0-f65.google.com ([209.85.214.65]:35311 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753904AbdGSWKK (ORCPT ); Wed, 19 Jul 2017 18:10:10 -0400 Received: by mail-it0-f65.google.com with SMTP id v127so855065itd.2 for ; Wed, 19 Jul 2017 15:10:10 -0700 (PDT) From: Trond Myklebust To: Chuck Lever , linux-nfs@vger.kernel.org Subject: [PATCH 07/20] NFS: Don't check request offset and size without holding a lock Date: Wed, 19 Jul 2017 18:09:42 -0400 Message-Id: <20170719220955.58210-8-trond.myklebust@primarydata.com> In-Reply-To: <20170719220955.58210-7-trond.myklebust@primarydata.com> References: <20170719220955.58210-1-trond.myklebust@primarydata.com> <20170719220955.58210-2-trond.myklebust@primarydata.com> <20170719220955.58210-3-trond.myklebust@primarydata.com> <20170719220955.58210-4-trond.myklebust@primarydata.com> <20170719220955.58210-5-trond.myklebust@primarydata.com> <20170719220955.58210-6-trond.myklebust@primarydata.com> <20170719220955.58210-7-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Request offsets and sizes are not guaranteed to be stable unless you are holding the request locked. Signed-off-by: Trond Myklebust --- fs/nfs/write.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index c940e615f5dc..84b6818e5278 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -523,6 +523,17 @@ nfs_lock_and_join_requests(struct page *page) total_bytes = head->wb_bytes; for (subreq = head->wb_this_page; subreq != head; subreq = subreq->wb_this_page) { + if (!nfs_lock_request(subreq)) { + /* releases page group bit lock and + * inode spin lock and all references */ + ret = nfs_unroll_locks_and_wait(inode, head, + subreq); + + if (ret == 0) + goto try_again; + + return ERR_PTR(ret); + } /* * Subrequests are always contiguous, non overlapping * and in order - but may be repeated (mirrored writes). @@ -533,21 +544,10 @@ nfs_lock_and_join_requests(struct page *page) } else if (WARN_ON_ONCE(subreq->wb_offset < head->wb_offset || ((subreq->wb_offset + subreq->wb_bytes) > (head->wb_offset + total_bytes)))) { + nfs_unlock_request(subreq); nfs_unroll_locks_and_wait(inode, head, subreq); return ERR_PTR(-EIO); } - - if (!nfs_lock_request(subreq)) { - /* releases page group bit lock and - * inode spin lock and all references */ - ret = nfs_unroll_locks_and_wait(inode, head, - subreq); - - if (ret == 0) - goto try_again; - - return ERR_PTR(ret); - } } /* Now that all requests are locked, make sure they aren't on any list. -- 2.13.3