> -----Original Message----- > From: Myklebust, Trond [mailto:Trond.Myklebust@xxxxxxxxxx] > Sent: Friday, June 01, 2012 5:22 AM > To: Peng Tao > Cc: linux-nfs@xxxxxxxxxxxxxxx; bharrosh@xxxxxxxxxxx; Peng, Tao > Subject: Re: [PATCH-v2 3/3] pnfsblock: call blk_plug functions for direct IO > > On Tue, 2012-05-29 at 12:38 +0800, Peng Tao wrote: > > NFS DIO bypasses generic DIO code path. So we need to plug/unplug > > on our own. > > > > Signed-off-by: Peng Tao <tao.peng@xxxxxxx> > > --- > > fs/nfs/blocklayout/blocklayout.c | 47 +++++++++++++++++++++++++++++++++++++- > > 1 files changed, 46 insertions(+), 1 deletions(-) > > > > diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c > > index bab432f..b48b08b 100644 > > --- a/fs/nfs/blocklayout/blocklayout.c > > +++ b/fs/nfs/blocklayout/blocklayout.c > > @@ -251,6 +251,7 @@ bl_read_pagelist(struct nfs_read_data *rdata) > > > > dprintk("%s enter nr_pages %u offset %lld count %u\n", __func__, > > rdata->pages.npages, f_offset, (unsigned int)rdata->args.count); > > + BUG_ON(header->dreq && header->layout_private == NULL); > > > > if (!bl_check_alignment(f_offset, rdata->args.count, PAGE_CACHE_MASK)) > > goto use_mds; > > @@ -320,9 +321,17 @@ out: > > bl_put_extent(cow_read); > > bl_submit_bio(READ, bio); > > put_parallel(par); > > + if (header->dreq && !header->moreio) { > > + blk_finish_plug((struct blk_plug *)header->layout_private); > > + kfree(header->layout_private); > > Wait... Why can't this just go in the block-specific ->pg_doio() > callback? Why does it need to go to your > read_pagelist()/write_pagelist()? > You are right. It can be moved to .pg_doio. The DIO alignment check should be moved there as well and then we can avoid allocating unnecessary nfs_read/write_data. It also eliminates the change in struct nfs_pgio_header. Thanks, Tao > > + } > > return PNFS_ATTEMPTED; > > > > - use_mds: > > +use_mds: > > + if (header->dreq) { > > + blk_finish_plug((struct blk_plug *)header->layout_private); > > + kfree(header->layout_private); > > + } > > dprintk("Giving up and using normal NFS\n"); > > return PNFS_NOT_ATTEMPTED; > > } > > @@ -575,6 +584,8 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync) > > unsigned long blkmask = PAGE_CACHE_MASK; > > > > dprintk("%s enter, %Zu@%lld\n", __func__, count, offset); > > + BUG_ON(header->dreq && header->layout_private == NULL); > > + > > /* Check for alignment first */ > > if (header->dreq) > > blkmask = NFS_SERVER(header->inode)->pnfs_blksize - 1; > > @@ -740,8 +751,16 @@ out: > > bl_put_extent(be); > > bl_submit_bio(WRITE, bio); > > put_parallel(par); > > + if (header->dreq && !header->moreio) { > > + blk_finish_plug((struct blk_plug *)header->layout_private); > > + kfree(header->layout_private); > > + } > > return PNFS_ATTEMPTED; > > out_mds: > > + if (header->dreq) { > > + blk_finish_plug((struct blk_plug *)header->layout_private); > > + kfree(header->layout_private); > > + } > > bl_put_extent(be); > > kfree(par); > > return PNFS_NOT_ATTEMPTED; > > @@ -1017,15 +1036,30 @@ bl_clear_layoutdriver(struct nfs_server *server) > > static void > > bl_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) > > { > > + BUG_ON(pgio->pg_layout_private != NULL); > > + > > if (!bl_check_alignment(req->wb_offset, req->wb_bytes, PAGE_CACHE_MASK)) > > nfs_pageio_reset_read_mds(pgio); > > else > > pnfs_generic_pg_init_read(pgio, req); > > + > > + if (pgio->pg_dreq && pgio->pg_lseg) { > > + struct blk_plug *plug; > > + /* Freed in bl_read_pagelist */ > > + plug = kmalloc(sizeof(struct blk_plug), GFP_KERNEL); > > + if (plug != NULL) { > > + blk_start_plug(plug); > > + pgio->pg_layout_private = plug; > > + } else > > + nfs_pageio_reset_read_mds(pgio); > > + } > > } > > > > static void > > bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) > > { > > + BUG_ON(pgio->pg_layout_private != NULL); > > + > > if (pgio->pg_dreq) { > > /* Direct write should be blksize aligned */ > > unsigned blkmask = NFS_SERVER(pgio->pg_inode)->pnfs_blksize - 1; > > @@ -1038,6 +1072,17 @@ bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) > > nfs_pageio_reset_write_mds(pgio); > > else > > pnfs_generic_pg_init_write(pgio, req); > > + > > + if (pgio->pg_dreq && pgio->pg_lseg) { > > + struct blk_plug *plug; > > + /* Freed in bl_write_pagelist */ > > + plug = kmalloc(sizeof(struct blk_plug), GFP_NOFS); > > + if (plug != NULL) { > > + blk_start_plug(plug); > > + pgio->pg_layout_private = plug; > > + } else > > + nfs_pageio_reset_write_mds(pgio); > > + } > > } > > > > static const struct nfs_pageio_ops bl_pg_read_ops = { > > -- > Trond Myklebust > Linux NFS client maintainer > > NetApp > Trond.Myklebust@xxxxxxxxxx > www.netapp.com ��.n��������+%������w��{.n�����{��w��� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
