> -----Original Message----- > From: linux-nfs-owner@xxxxxxxxxxxxxxx [mailto:linux-nfs-owner@xxxxxxxxxxxxxxx] > On Behalf Of Trond Myklebust > Sent: Thursday, July 28, 2011 3:47 AM > To: Jim Rees > Cc: linux-nfs@xxxxxxxxxxxxxxx; peter honeyman > Subject: Re: [PATCH v3 04/25] NFS41: save layoutcommit cred after first successful > layoutget > > On Wed, 2011-07-27 at 14:40 -0400, Jim Rees wrote: > > From: Peng Tao <bergwolf@xxxxxxxxx> > > > > Save it in layout header instead of in every segment. > > > > Signed-off-by: Peng Tao <peng_tao@xxxxxxx> > > --- > > fs/nfs/pnfs.c | 12 ++++++------ > > fs/nfs/pnfs.h | 1 - > > 2 files changed, 6 insertions(+), 7 deletions(-) > > > > diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c > > index dae19dd..fbebd2a 100644 > > --- a/fs/nfs/pnfs.c > > +++ b/fs/nfs/pnfs.c > > @@ -211,6 +211,7 @@ destroy_layout_hdr(struct pnfs_layout_hdr *lo) > > dprintk("%s: freeing layout cache %p\n", __func__, lo); > > BUG_ON(!list_empty(&lo->plh_layouts)); > > NFS_I(lo->plh_inode)->layout = NULL; > > + put_rpccred(lo->plh_lc_cred); > > pnfs_free_layout_hdr(lo); > > } > > > > @@ -1007,6 +1008,10 @@ pnfs_update_layout(struct inode *ino, > > list_del_init(&lo->plh_layouts); > > spin_unlock(&clp->cl_lock); > > } > > + if (first) { > > + lo->plh_lc_cred = > > + get_rpccred(ctx->state->owner->so_cred); > > + } > > Hmm... This whole 'first' thing is inherently racy. What if two threads > are calling pnfs_update_layout at the same time: they both see > list_empty(&lo->plh_segs), and both conclude that they need to > initialise the layout header. _BOOM_.... > > The correct thing to do here is either to initialise the layout header > correctly inside pnfs_find_alloc_layout(), or to add a flag for > ->plh_flags that can be used with test_and_clear_bit() to get _one_ of > the processes to perform the initialisation. > Personally, I'd prefer the former. Will move it inside layout header init. Thanks. Cheers, Tao > > > -- > Trond Myklebust > Linux NFS client maintainer > > NetApp > Trond.Myklebust@xxxxxxxxxx > www.netapp.com > > -- > 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 ��.n��������+%������w��{.n�����{��w��� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
