On Tue, Jun 14, 2011 at 6:40 AM, <tao.peng@xxxxxxx> wrote: > 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. I agree there is a problem here that affects the generic code. I've just sent a separate patch that deals with that. Fred > >> >> > 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 > -- 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
