From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [RFC PATCH 1/2] Add unlocked version of igrab. Date: Sun, 27 Mar 2011 20:54:23 -0600 Message-ID: <20110328025423.GN13806@parisc-linux.org> References: <1301277361-9453-1-git-send-email-ryan@bluewatersys.com> <1301277361-9453-2-git-send-email-ryan@bluewatersys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, dchinner-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ryan Mallon Return-path: Content-Disposition: inline In-Reply-To: <1301277361-9453-2-git-send-email-ryan-7Wk5F4Od5/oYd5yxfr4S2w@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Mon, Mar 28, 2011 at 02:56:00PM +1300, Ryan Mallon wrote: > Commit 250df6ed274d767da844a5d9f05720b804240197 "fs: protect > inode->i_state with inode->i_lock" changes igrab to acquire inode->i_lock, > however some callees, notably nfs_inode_add_request, already hold the lock > when calling igrab. I think a better solution to your problem is to notice that this is called in the context of doing a write to an inode. That means we must already have a reference count on this inode, so it can't possibly be in I_FREEING or I_WILL_FREE. That means we can just call __iget() instead ... except that __iget isn't exported to modules. So we could just bump the refcount by hand ... or we could EXPORT_SYMBOL(__iget). Or Al's going to swear a lot about what NFS is doing here and how it's utterly misdesigned. Anyway, this patch could be part of the solution. diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 85d7525..330cef3 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -390,7 +390,7 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req) error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req); BUG_ON(error); if (!nfsi->npages) { - igrab(inode); + __iget(inode); if (nfs_have_delegation(inode, FMODE_WRITE)) nfsi->change_attr++; } -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html