Hi, Fred, > -----Original Message----- > From: linux-nfs-owner@xxxxxxxxxxxxxxx [mailto:linux-nfs-owner@xxxxxxxxxxxxxxx] > On Behalf Of Fred Isaman > Sent: Monday, June 13, 2011 10:37 PM > To: Jim Rees > Cc: linux-nfs@xxxxxxxxxxxxxxx; peter honeyman > Subject: Re: [PATCH 03/34] pnfs: let layoutcommit code handle multiple segments > > On Sun, Jun 12, 2011 at 7:43 PM, Jim Rees <rees@xxxxxxxxx> wrote: > > From: Peng Tao <bergwolf@xxxxxxxxx> > > > > Some layout driver like block will have multiple segments. > > Generic code should be able to handle it. > > > > Signed-off-by: Peng Tao <peng_tao@xxxxxxx> > > --- > > fs/nfs/pnfs.c | 17 +++++++++++++---- > > fs/nfs/pnfs.h | 1 + > > 2 files changed, 14 insertions(+), 4 deletions(-) > > > > diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c > > index e3d618b..f03a5e0 100644 > > --- a/fs/nfs/pnfs.c > > +++ b/fs/nfs/pnfs.c > > @@ -892,7 +892,7 @@ pnfs_find_lseg(struct pnfs_layout_hdr *lo, > > dprintk("%s:Begin\n", __func__); > > > > assert_spin_locked(&lo->plh_inode->i_lock); > > - list_for_each_entry(lseg, &lo->plh_segs, pls_list) { > > + list_for_each_entry_reverse(lseg, &lo->plh_segs, pls_list) { > > This is a sortred list, and the order of search matters. You can't > just reverse it here. The layout segment list is in offset increasing order. But the lookup code here assumes it's a decreasing ordered list. To fix it, we should either reverse lookup the list, or change the break condition test. Otherwise lookup always fails if not matching the first one. > > > if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) && > > is_matching_lseg(&lseg->pls_range, range)) { > > ret = get_lseg(lseg); > > @@ -1193,10 +1193,18 @@ pnfs_try_to_read_data(struct nfs_read_data *rdata, > > static struct pnfs_layout_segment *pnfs_list_write_lseg(struct inode *inode) > > { > > struct pnfs_layout_segment *lseg, *rv = NULL; > > + loff_t max_pos = 0; > > + > > + list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) { > > + if (lseg->pls_range.iomode == IOMODE_RW) { > > + if (max_pos < lseg->pls_end_pos) > > + max_pos = lseg->pls_end_pos; > > + if (test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, > &lseg->pls_flags)) > > + rv = lseg; > > + } > > + } > > + rv->pls_end_pos = max_pos; > > > > The idea here was that it could be extended to use segment by > returning a list of affected lsegs, > not so,e random one. Because otherwise you have problems with the > fact that relevant but not > returned lsegs are going to get there refcounts messed up. The above code relies on NFS_INO_LAYOUTCOMMIT bit to ensure that only one inode lseg has NFS_LSEG_LAYOUTCOMMIT set. But, you are right. The layoutcommit code needs a second thought. How about making it return a list of affected lsegs and pass them around layoutcommit_procs? Thanks, Tao > > Fred > > > - list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) > > - if (lseg->pls_range.iomode == IOMODE_RW) > > - rv = lseg; > > return rv; > > } > > > > @@ -1211,6 +1219,7 @@ pnfs_set_layoutcommit(struct nfs_write_data *wdata) > > if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) { > > /* references matched in nfs4_layoutcommit_release */ > > get_lseg(wdata->lseg); > > + set_bit(NFS_LSEG_LAYOUTCOMMIT, > &wdata->lseg->pls_flags); > > wdata->lseg->pls_lc_cred = > > get_rpccred(wdata->args.context->state->owner- > >so_cred); > > mark_as_dirty = true; > > diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h > > index b071b56..a3fc0f2 100644 > > --- a/fs/nfs/pnfs.h > > +++ b/fs/nfs/pnfs.h > > @@ -36,6 +36,7 @@ > > enum { > > NFS_LSEG_VALID = 0, /* cleared when lseg is recalled/returned */ > > NFS_LSEG_ROC, /* roc bit received from server */ > > + NFS_LSEG_LAYOUTCOMMIT, /* layoutcommit bit set for > layoutcommit */ > > }; > > > > struct pnfs_layout_segment { > > -- > > 1.7.4.1 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
