From: Benny Halevy Subject: Re: [PATCH 12/16] SQUASHME pnfs-submit: reference layout across layoutcommit Date: Mon, 12 Jul 2010 21:29:58 +0300 Message-ID: <4C3B5F26.1080100@panasas.com> References: <1278542063-4009-1-git-send-email-andros@netapp.com> <1278542063-4009-2-git-send-email-andros@netapp.com> <1278542063-4009-3-git-send-email-andros@netapp.com> <1278542063-4009-4-git-send-email-andros@netapp.com> <1278542063-4009-5-git-send-email-andros@netapp.com> <1278542063-4009-6-git-send-email-andros@netapp.com> <1278542063-4009-7-git-send-email-andros@netapp.com> <1278542063-4009-8-git-send-email-andros@netapp.com> <1278542063-4009-9-git-send-email-andros@netapp.com> <1278542063-4009-10-git-send-email-andros@netapp.com> <1278542063-4009-11-git-send-email-andros@netapp.com> <1278542063-4009-12-git-send-email-andros@netapp.com> <1278542063-4009-13-git-send-email-andros@netapp.com> <4C3B4EAD.7070404@panasas.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: linux-nfs@vger.kernel.org To: "William A. (Andy) Adamson" Return-path: Received: from daytona.panasas.com ([67.152.220.89]:42948 "EHLO daytona.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754061Ab0GLSaG (ORCPT ); Mon, 12 Jul 2010 14:30:06 -0400 In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Jul. 12, 2010, 21:27 +0300, "William A. (Andy) Adamson" wrote: > On Mon, Jul 12, 2010 at 1:19 PM, Benny Halevy wrote: >> On Jul. 08, 2010, 1:34 +0300, andros@netapp.com wrote: >>> From: Andy Adamson >>> >>> Signed-off-by: Andy Adamson >>> --- >>> fs/nfs/nfs4proc.c | 2 ++ >>> fs/nfs/pnfs.c | 13 +++++++++++++ >>> fs/nfs/pnfs.h | 1 + >>> 3 files changed, 16 insertions(+), 0 deletions(-) >>> >>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c >>> index 6acebc3..f763746 100644 >>> --- a/fs/nfs/nfs4proc.c >>> +++ b/fs/nfs/nfs4proc.c >>> @@ -5565,6 +5565,8 @@ static void pnfs_layoutcommit_release(void *lcdata) >>> struct pnfs_layoutcommit_data *data = >>> (struct pnfs_layoutcommit_data *)lcdata; >>> >>> + /* Matched by get_layout in pnfs_layoutcommit_inode */ >>> + put_layout(data->args.inode); >>> put_rpccred(data->cred); >>> pnfs_layoutcommit_free(lcdata); >>> } >>> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c >>> index aa16e5d..d42c5da 100644 >>> --- a/fs/nfs/pnfs.c >>> +++ b/fs/nfs/pnfs.c >>> @@ -354,6 +354,15 @@ put_layout_locked(struct pnfs_layout_type *lo) >>> } >>> >>> void >>> +put_layout(struct inode *inode) >>> +{ >>> + spin_lock(&inode->i_lock); >>> + put_layout_locked(NFS_I(inode)->layout); >>> + spin_unlock(&inode->i_lock); >>> + >>> +} >>> + >>> +void >>> pnfs_layout_release(struct pnfs_layout_type *lo, >>> struct nfs4_pnfs_layout_segment *range) >>> { >>> @@ -1598,6 +1607,9 @@ pnfs_layoutcommit_inode(struct inode *inode, int sync) >>> __clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->layout->pnfs_layout_state); >>> pnfs_get_layout_stateid(&data->args.stateid, nfsi->layout); >>> >>> + /* Reference for layoutcommit matched in pnfs_layoutcommit_release */ >>> + get_layout(NFS_I(inode)->layout); >>> + >> >> So from the 30000 foot level, I need to remind myself what do >> we need the refcount on the layout hdr (pnfs_layout_type) for? > >> Can we really use it detached from the inode? NO >> Is it only for debugging to make catch the case that the inode >> is released while there are references to the layout? > > When we migrate the filesystem, we need to reap the nfs_inode->layout > while keeping the nfs_inode. > But how does the refcount help us with that? Don't we have to do this synchronously before reusing the nfs_inode? Benny > Same with server reboot, network partition, and use of a different replica. > > -->Andy > >> >> Benny >> >>> spin_unlock(&inode->i_lock); >>> >>> /* Set up layout commit args */ >>> @@ -1606,6 +1618,7 @@ pnfs_layoutcommit_inode(struct inode *inode, int sync) >>> if (status) { >>> /* The layout driver failed to setup the layoutcommit */ >>> put_rpccred(data->cred); >>> + put_layout(inode); >>> goto out_free; >>> } >>> status = pnfs4_proc_layoutcommit(data, sync); >>> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h >>> index 9b0fed4..e04b9d4 100644 >>> --- a/fs/nfs/pnfs.h >>> +++ b/fs/nfs/pnfs.h >>> @@ -64,6 +64,7 @@ void pnfs_layout_release(struct pnfs_layout_type *, struct nfs4_pnfs_layout_segm >>> void pnfs_set_layout_stateid(struct pnfs_layout_type *lo, >>> const nfs4_stateid *stateid); >>> void pnfs_destroy_layout(struct nfs_inode *); >>> +void put_layout(struct inode *inode); >>> >>> #define PNFS_EXISTS_LDIO_OP(srv, opname) ((srv)->pnfs_curr_ld && \ >>> (srv)->pnfs_curr_ld->ld_io_ops && \ >> >> -- >> 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 >>