From: Boaz Harrosh Subject: Re: [PATCH 1/1] SQUASHME pnfs-submit: replace layoutcommit_ctx with rpc_cred Date: Mon, 24 May 2010 21:20:55 +0300 Message-ID: <4BFAC387.6010202@panasas.com> References: <1274371457-10003-1-git-send-email-andros@netapp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Tao Guo , bhalevy@panasas.com, linux-nfs@vger.kernel.org To: "William A. (Andy) Adamson" Return-path: Received: from daytona.panasas.com ([67.152.220.89]:57146 "EHLO daytona.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754343Ab0EXSU7 (ORCPT ); Mon, 24 May 2010 14:20:59 -0400 In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On 05/24/2010 08:25 PM, William A. (Andy) Adamson wrote: > On Mon, May 24, 2010 at 12:02 PM, Tao Guo wrote: >> On Mon, May 24, 2010 at 9:43 PM, William A. (Andy) Adamson >> wrote: >>> On Mon, May 24, 2010 at 2:37 AM, Tao Guo wrote: >>>> I see... But what if sync == 1? At that time, data must have already >>>> been freed, so you should not use data->cred anymore. >>> >>> Agreed. >>> >>> Since LAYOUTCOMMIT is not called after close, we can get rid of taking >>> the reference all together since a reference is taken on OPEN and >>> dropped on CLOSE. > > I forgot memory mapped files where writes can occur after the close, > and so layoutcommit can also occur after the close. So, I will keep > the get_rpccred in pnfs_need_layout commit and resend this patch with > the put_rpccred in the layoutcommit done routine. > Andy I get hangs on: data->is_sync = sync; status = pnfs4_proc_layoutcommit(data); + put_rpccred(data->cred); with sync==1 like Tao Guo said could you send the updated patch? Boaz >>> >>> -->Andy >> I agree. However that will change several functions' interface I guess. >> >> I still have a question: why some procedures need to set rpc_cred >> whereas some needn't ? what is the connection between ctx's rpc_cred >> and nfs4_state_owner's so_cred? Any guidance will be appreciated... > > Here's my take on an answer... > > If an rpc_cred is not specified in the rpc_msg then the fsuid, fsgid, > and group info toe the current_cred is used to lookup an rpc_cred. > RPC's can be sent from several tasks - rpciod vrs the application task > for example. OPEN, CLOSE, LOCK, UNLOCK, READ, WRITE (and memmapped > I/O) should all be sent with the credential that opened the file. So, > in order to ensure this the nfs4_state_owner->so_cred is used for > these compounds even if the task is rpciod with root fsuid/fsgid. The > nfs_open_context rpc_cred is the nfs4_state_owner so_cred. The > nfs_open_context can exist longer than the nfs4_state_owner. > > I think LAYOUTCOMMIT also wants to use the credential that did the I/O > - not for the file layout driver which doesn't care, but for the > object and block layout drivers that use the layout as a lock and > where a permissions check (?) is done on LAYOUTCOMMIT. > > Currently, LAYOUTGET and LAYOUTRETURN don't set the rpc_cred. This is > because the layout can last past opens and closes. If we ever want to > support EXCHGID4_FLAG_BIND_PRINC_STATEID we will need to remember the > cred and set it for these calls. > > -->Andy > > > >> >>>> >>>> -- >>>> tao. >>>> >>> >> >> >> >> -- >> tao. >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >