Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx12.netapp.com ([216.240.18.77]:63126 "EHLO mx12.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932771Ab3CUOcf convert rfc822-to-8bit (ORCPT ); Thu, 21 Mar 2013 10:32:35 -0400 From: "Myklebust, Trond" To: "linux-nfs@vger.kernel.org" CC: Benny Halevy , Boaz Harrosh , Peng Tao Subject: Re: [PATCH v2 1/3] NFSv4.1: Fix a race in pNFS layoutcommit Date: Thu, 21 Mar 2013 14:32:34 +0000 Message-ID: <1363876352.3557.10.camel@leira.trondhjem.org> References: <1363875181-7147-1-git-send-email-Trond.Myklebust@netapp.com> In-Reply-To: <1363875181-7147-1-git-send-email-Trond.Myklebust@netapp.com> Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, 2013-03-21 at 10:12 -0400, Trond Myklebust wrote: > We need to clear the NFS_LSEG_LAYOUTCOMMIT bits atomically with the > NFS_INO_LAYOUTCOMMIT bit, otherwise we may end up with situations > where the two are out of sync. > The first half of the problem is to ensure that pnfs_layoutcommit_inode > clears the NFS_LSEG_LAYOUTCOMMIT bit through pnfs_list_write_lseg. > We still need to keep the reference to those segments until the RPC call > is finished, so in order to make it clear _where_ those references come > from, we add a helper pnfs_list_write_lseg_done() that cleans up after > pnfs_list_write_lseg. > > Signed-off-by: Trond Myklebust > Acked-by: Benny Halevy > Cc: stable@vger.kernel.org > --- > fs/nfs/nfs4proc.c | 14 -------------- > fs/nfs/pnfs.c | 19 ++++++++++++++++++- > 2 files changed, 18 insertions(+), 15 deletions(-) > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index b2671cb..6ccdd4f 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -6416,22 +6416,8 @@ nfs4_layoutcommit_done(struct rpc_task *task, void *calldata) > static void nfs4_layoutcommit_release(void *calldata) > { > struct nfs4_layoutcommit_data *data = calldata; > - struct pnfs_layout_segment *lseg, *tmp; > - unsigned long *bitlock = &NFS_I(data->args.inode)->flags; > > pnfs_cleanup_layoutcommit(data); > - /* Matched by references in pnfs_set_layoutcommit */ > - list_for_each_entry_safe(lseg, tmp, &data->lseg_list, pls_lc_list) { > - list_del_init(&lseg->pls_lc_list); > - if (test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, > - &lseg->pls_flags)) > - pnfs_put_lseg(lseg); > - } > - > - clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock); > - smp_mb__after_clear_bit(); > - wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING); > - > put_rpccred(data->cred); > kfree(data); > } > diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c > index 48ac5aa..c6bbb53 100644 > --- a/fs/nfs/pnfs.c > +++ b/fs/nfs/pnfs.c > @@ -1746,11 +1746,27 @@ static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp) > > list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) { > if (lseg->pls_range.iomode == IOMODE_RW && > - test_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) > + test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) > list_add(&lseg->pls_lc_list, listp); > } > } > > +void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp) Doh! This needs to be declared static... Will fix. > +{ > + struct pnfs_layout_segment *lseg, *tmp; > + unsigned long *bitlock = &NFS_I(inode)->flags; > + > + /* Matched by references in pnfs_set_layoutcommit */ > + list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) { > + list_del_init(&lseg->pls_lc_list); > + pnfs_put_lseg(lseg); > + } > + > + clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock); > + smp_mb__after_clear_bit(); > + wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING); > +} > + > void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg) > { > pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode); > @@ -1795,6 +1811,7 @@ void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data) > > if (nfss->pnfs_curr_ld->cleanup_layoutcommit) > nfss->pnfs_curr_ld->cleanup_layoutcommit(data); > + pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list); > } > > /* -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com