* [PATCH] NFSD: Don't give out read delegations on exclusive creates
@ 2013-05-15 18:51 Steve Dickson
2013-05-21 18:43 ` Steve Dickson
2013-05-21 19:23 ` J. Bruce Fields
0 siblings, 2 replies; 7+ messages in thread
From: Steve Dickson @ 2013-05-15 18:51 UTC (permalink / raw)
To: Bruce Fields; +Cc: Linux NFS Mailing list
When an exclusive create is done with the mode bits
set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
causes a OPEN op followed by a SETATTR op. When a
read delegation is given in the OPEN, it causes
the SETATTR to delay with EAGAIN until the
delegation is recalled.
This patch caused exclusive creates to give out
a write delegation (which turn into no delegation)
which allows the SETATTR seamlessly succeed.
Signed-off-by: Steve Dickson <steved@redhat.com>
---
fs/nfsd/nfs4state.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 316ec84..6b45d0e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3035,8 +3035,16 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
goto out;
if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
flag = NFS4_OPEN_DELEGATE_WRITE;
- else
- flag = NFS4_OPEN_DELEGATE_READ;
+ else {
+ switch(open->op_createmode) {
+ case NFS4_CREATE_EXCLUSIVE:
+ case NFS4_CREATE_EXCLUSIVE4_1:
+ flag = NFS4_OPEN_DELEGATE_WRITE;
+ break;
+ default:
+ flag = NFS4_OPEN_DELEGATE_READ;
+ }
+ }
break;
default:
goto out;
--
1.8.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates
2013-05-15 18:51 [PATCH] NFSD: Don't give out read delegations on exclusive creates Steve Dickson
@ 2013-05-21 18:43 ` Steve Dickson
2013-05-21 18:52 ` J. Bruce Fields
2013-05-21 19:23 ` J. Bruce Fields
1 sibling, 1 reply; 7+ messages in thread
From: Steve Dickson @ 2013-05-21 18:43 UTC (permalink / raw)
To: Steve Dickson; +Cc: Bruce Fields, Linux NFS Mailing list
Hey Bruce,
Ping... ;-) I just pull from your for-3.11-incoming branch
and notice it was not there...
This really does help with exclusive creates
not being delayed... So you might want to consider it...
steved.
On 15/05/13 14:51, Steve Dickson wrote:
> When an exclusive create is done with the mode bits
> set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
> causes a OPEN op followed by a SETATTR op. When a
> read delegation is given in the OPEN, it causes
> the SETATTR to delay with EAGAIN until the
> delegation is recalled.
>
> This patch caused exclusive creates to give out
> a write delegation (which turn into no delegation)
> which allows the SETATTR seamlessly succeed.
>
> Signed-off-by: Steve Dickson <steved@redhat.com>
> ---
> fs/nfsd/nfs4state.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 316ec84..6b45d0e 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -3035,8 +3035,16 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
> goto out;
> if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
> flag = NFS4_OPEN_DELEGATE_WRITE;
> - else
> - flag = NFS4_OPEN_DELEGATE_READ;
> + else {
> + switch(open->op_createmode) {
> + case NFS4_CREATE_EXCLUSIVE:
> + case NFS4_CREATE_EXCLUSIVE4_1:
> + flag = NFS4_OPEN_DELEGATE_WRITE;
> + break;
> + default:
> + flag = NFS4_OPEN_DELEGATE_READ;
> + }
> + }
> break;
> default:
> goto out;
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates
2013-05-21 18:43 ` Steve Dickson
@ 2013-05-21 18:52 ` J. Bruce Fields
0 siblings, 0 replies; 7+ messages in thread
From: J. Bruce Fields @ 2013-05-21 18:52 UTC (permalink / raw)
To: Steve Dickson; +Cc: Bruce Fields, Linux NFS Mailing list
On Tue, May 21, 2013 at 02:43:16PM -0400, Steve Dickson wrote:
> Hey Bruce,
>
> Ping... ;-) I just pull from your for-3.11-incoming branch
> and notice it was not there...
Whoops, this had gotten buried in my inbox somehow. I'll take a look,
thanks for the reminder.
--b.
>
> This really does help with exclusive creates
> not being delayed... So you might want to consider it...
>
> steved.
>
> On 15/05/13 14:51, Steve Dickson wrote:
> > When an exclusive create is done with the mode bits
> > set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
> > causes a OPEN op followed by a SETATTR op. When a
> > read delegation is given in the OPEN, it causes
> > the SETATTR to delay with EAGAIN until the
> > delegation is recalled.
> >
> > This patch caused exclusive creates to give out
> > a write delegation (which turn into no delegation)
> > which allows the SETATTR seamlessly succeed.
> >
> > Signed-off-by: Steve Dickson <steved@redhat.com>
> > ---
> > fs/nfsd/nfs4state.c | 12 ++++++++++--
> > 1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 316ec84..6b45d0e 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -3035,8 +3035,16 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
> > goto out;
> > if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
> > flag = NFS4_OPEN_DELEGATE_WRITE;
> > - else
> > - flag = NFS4_OPEN_DELEGATE_READ;
> > + else {
> > + switch(open->op_createmode) {
> > + case NFS4_CREATE_EXCLUSIVE:
> > + case NFS4_CREATE_EXCLUSIVE4_1:
> > + flag = NFS4_OPEN_DELEGATE_WRITE;
> > + break;
> > + default:
> > + flag = NFS4_OPEN_DELEGATE_READ;
> > + }
> > + }
> > break;
> > default:
> > goto out;
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates
2013-05-15 18:51 [PATCH] NFSD: Don't give out read delegations on exclusive creates Steve Dickson
2013-05-21 18:43 ` Steve Dickson
@ 2013-05-21 19:23 ` J. Bruce Fields
2013-05-21 20:25 ` J. Bruce Fields
2013-05-21 20:26 ` J. Bruce Fields
1 sibling, 2 replies; 7+ messages in thread
From: J. Bruce Fields @ 2013-05-21 19:23 UTC (permalink / raw)
To: Steve Dickson; +Cc: Bruce Fields, Linux NFS Mailing list
On Wed, May 15, 2013 at 02:51:49PM -0400, Steve Dickson wrote:
> When an exclusive create is done with the mode bits
> set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
so implicitly O_RDONLY. Is that common? Maybe so, OK.
> causes a OPEN op followed by a SETATTR op. When a
> read delegation is given in the OPEN, it causes
> the SETATTR to delay with EAGAIN until the
> delegation is recalled.
>
> This patch caused exclusive creates to give out
> a write delegation (which turn into no delegation)
> which allows the SETATTR seamlessly succeed.
OK. May as well make it apply to all creates, though, I think?
Any create flag seems like a sign the file's likely to be modified soon,
hence isn't a good candidate for a read delegation.
I find it a little confusing the way we set this WRITE flag and then
depend on later code to turn that into no delegation, maybe we should
fix that.
--b.
>
> Signed-off-by: Steve Dickson <steved@redhat.com>
> ---
> fs/nfsd/nfs4state.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 316ec84..6b45d0e 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -3035,8 +3035,16 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
> goto out;
> if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
> flag = NFS4_OPEN_DELEGATE_WRITE;
> - else
> - flag = NFS4_OPEN_DELEGATE_READ;
> + else {
> + switch(open->op_createmode) {
> + case NFS4_CREATE_EXCLUSIVE:
> + case NFS4_CREATE_EXCLUSIVE4_1:
> + flag = NFS4_OPEN_DELEGATE_WRITE;
> + break;
> + default:
> + flag = NFS4_OPEN_DELEGATE_READ;
> + }
> + }
> break;
> default:
> goto out;
> --
> 1.8.1.4
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates
2013-05-21 19:23 ` J. Bruce Fields
@ 2013-05-21 20:25 ` J. Bruce Fields
2013-05-22 16:20 ` J. Bruce Fields
2013-05-21 20:26 ` J. Bruce Fields
1 sibling, 1 reply; 7+ messages in thread
From: J. Bruce Fields @ 2013-05-21 20:25 UTC (permalink / raw)
To: Steve Dickson; +Cc: Bruce Fields, Linux NFS Mailing list
On Tue, May 21, 2013 at 03:23:38PM -0400, bfields wrote:
> On Wed, May 15, 2013 at 02:51:49PM -0400, Steve Dickson wrote:
> > When an exclusive create is done with the mode bits
> > set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
>
> so implicitly O_RDONLY. Is that common? Maybe so, OK.
>
> > causes a OPEN op followed by a SETATTR op. When a
> > read delegation is given in the OPEN, it causes
> > the SETATTR to delay with EAGAIN until the
> > delegation is recalled.
> >
> > This patch caused exclusive creates to give out
> > a write delegation (which turn into no delegation)
> > which allows the SETATTR seamlessly succeed.
>
> OK. May as well make it apply to all creates, though, I think?
> Any create flag seems like a sign the file's likely to be modified soon,
> hence isn't a good candidate for a read delegation.
That would look like the following.
--b.
commit 3f47b6220ca6b08a7ab86baaaab87389707a3308
Author: Steve Dickson <steved@redhat.com>
Date: Wed May 15 14:51:49 2013 -0400
NFSD: Don't give out read delegations on exclusive creates
When an exclusive create is done with the mode bits
set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
causes a OPEN op followed by a SETATTR op. When a
read delegation is given in the OPEN, it causes
the SETATTR to delay with EAGAIN until the
delegation is recalled.
This patch caused exclusive creates to give out
a write delegation (which turn into no delegation)
which allows the SETATTR seamlessly succeed.
Signed-off-by: Steve Dickson <steved@redhat.com>
[bfields: do this for any CREATE, not just exclusive; comment]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c4f6339..44dcea9 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3113,8 +3113,17 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
goto out;
if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
goto out;
+ /*
+ * Also, if the file was opened for write or
+ * create, there's a good chance the client's
+ * about to write to it, resulting in an
+ * immediate recall (since we don't support
+ * write delegations):
+ */
if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
flag = NFS4_OPEN_DELEGATE_WRITE;
+ else if (open->op_create == NFS4_OPEN_CREATE)
+ flag = NFS4_OPEN_DELEGATE_WRITE;
else
flag = NFS4_OPEN_DELEGATE_READ;
break;
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates
2013-05-21 19:23 ` J. Bruce Fields
2013-05-21 20:25 ` J. Bruce Fields
@ 2013-05-21 20:26 ` J. Bruce Fields
1 sibling, 0 replies; 7+ messages in thread
From: J. Bruce Fields @ 2013-05-21 20:26 UTC (permalink / raw)
To: Steve Dickson; +Cc: Bruce Fields, Linux NFS Mailing list
On Tue, May 21, 2013 at 03:23:38PM -0400, bfields wrote:
> On Wed, May 15, 2013 at 02:51:49PM -0400, Steve Dickson wrote:
> > When an exclusive create is done with the mode bits
> > set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
>
> so implicitly O_RDONLY. Is that common? Maybe so, OK.
>
> > causes a OPEN op followed by a SETATTR op. When a
> > read delegation is given in the OPEN, it causes
> > the SETATTR to delay with EAGAIN until the
> > delegation is recalled.
> >
> > This patch caused exclusive creates to give out
> > a write delegation (which turn into no delegation)
> > which allows the SETATTR seamlessly succeed.
>
> OK. May as well make it apply to all creates, though, I think?
> Any create flag seems like a sign the file's likely to be modified soon,
> hence isn't a good candidate for a read delegation.
>
> I find it a little confusing the way we set this WRITE flag and then
> depend on later code to turn that into no delegation, maybe we should
> fix that.
And some cleanup.
--b.
commit e34bc725ce160cd619cd09420a861426099e860f
Author: J. Bruce Fields <bfields@redhat.com>
Date: Tue May 21 16:21:25 2013 -0400
nfsd4: clean up nfs4_open_delegation
The nfs4_open_delegation logic is unecessarily baroque.
Also stop pretending we support write delegations in several places.
Some day we will support write delegations, but when that happens adding
back in these flag parameters will be the easy part. For now they're
just confusing.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 44dcea9..fcc0610 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -364,19 +364,12 @@ static struct nfs4_ol_stateid * nfs4_alloc_stateid(struct nfs4_client *clp)
}
static struct nfs4_delegation *
-alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh, u32 type)
+alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh)
{
struct nfs4_delegation *dp;
struct nfs4_file *fp = stp->st_file;
dprintk("NFSD alloc_init_deleg\n");
- /*
- * Major work on the lease subsystem (for example, to support
- * calbacks on stat) will be required before we can support
- * write delegations properly.
- */
- if (type != NFS4_OPEN_DELEGATE_READ)
- return NULL;
if (fp->fi_had_conflict)
return NULL;
if (num_delegations > max_delegations)
@@ -397,7 +390,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
INIT_LIST_HEAD(&dp->dl_recall_lru);
get_nfs4_file(fp);
dp->dl_file = fp;
- dp->dl_type = type;
+ dp->dl_type = NFS4_OPEN_DELEGATE_READ;
fh_copy_shallow(&dp->dl_fh, ¤t_fh->fh_handle);
dp->dl_time = 0;
atomic_set(&dp->dl_count, 1);
@@ -3020,13 +3013,13 @@ static struct file_lock *nfs4_alloc_init_lease(struct nfs4_delegation *dp, int f
return fl;
}
-static int nfs4_setlease(struct nfs4_delegation *dp, int flag)
+static int nfs4_setlease(struct nfs4_delegation *dp)
{
struct nfs4_file *fp = dp->dl_file;
struct file_lock *fl;
int status;
- fl = nfs4_alloc_init_lease(dp, flag);
+ fl = nfs4_alloc_init_lease(dp, NFS4_OPEN_DELEGATE_READ);
if (!fl)
return -ENOMEM;
fl->fl_file = find_readable_file(fp);
@@ -3044,12 +3037,12 @@ static int nfs4_setlease(struct nfs4_delegation *dp, int flag)
return 0;
}
-static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
+static int nfs4_set_delegation(struct nfs4_delegation *dp)
{
struct nfs4_file *fp = dp->dl_file;
if (!fp->fi_lease)
- return nfs4_setlease(dp, flag);
+ return nfs4_setlease(dp);
spin_lock(&recall_lock);
if (fp->fi_had_conflict) {
spin_unlock(&recall_lock);
@@ -3085,6 +3078,9 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
/*
* Attempt to hand out a delegation.
+ *
+ * Note we don't support write delegations, and won't until the vfs has
+ * proper support for them.
*/
static void
nfs4_open_delegation(struct net *net, struct svc_fh *fh,
@@ -3093,26 +3089,26 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
struct nfs4_delegation *dp;
struct nfs4_openowner *oo = container_of(stp->st_stateowner, struct nfs4_openowner, oo_owner);
int cb_up;
- int status = 0, flag = 0;
+ int status = 0;
cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
- flag = NFS4_OPEN_DELEGATE_NONE;
open->op_recall = 0;
switch (open->op_claim_type) {
case NFS4_OPEN_CLAIM_PREVIOUS:
if (!cb_up)
open->op_recall = 1;
- flag = open->op_delegate_type;
- if (flag == NFS4_OPEN_DELEGATE_NONE)
- goto out;
+ if (open->op_delegate_type != NFS4_OPEN_DELEGATE_READ)
+ goto out_no_deleg;
break;
case NFS4_OPEN_CLAIM_NULL:
- /* Let's not give out any delegations till everyone's
- * had the chance to reclaim theirs.... */
+ /*
+ * Let's not give out any delegations till everyone's
+ * had the chance to reclaim theirs....
+ */
if (locks_in_grace(net))
- goto out;
+ goto out_no_deleg;
if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
- goto out;
+ goto out_no_deleg;
/*
* Also, if the file was opened for write or
* create, there's a good chance the client's
@@ -3121,20 +3117,17 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
* write delegations):
*/
if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
- flag = NFS4_OPEN_DELEGATE_WRITE;
- else if (open->op_create == NFS4_OPEN_CREATE)
- flag = NFS4_OPEN_DELEGATE_WRITE;
- else
- flag = NFS4_OPEN_DELEGATE_READ;
+ goto out_no_deleg;
+ if (open->op_create == NFS4_OPEN_CREATE)
+ goto out_no_deleg;
break;
default:
- goto out;
+ goto out_no_deleg;
}
-
- dp = alloc_init_deleg(oo->oo_owner.so_client, stp, fh, flag);
+ dp = alloc_init_deleg(oo->oo_owner.so_client, stp, fh);
if (dp == NULL)
goto out_no_deleg;
- status = nfs4_set_delegation(dp, flag);
+ status = nfs4_set_delegation(dp);
if (status)
goto out_free;
@@ -3142,24 +3135,21 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
dprintk("NFSD: delegation stateid=" STATEID_FMT "\n",
STATEID_VAL(&dp->dl_stid.sc_stateid));
-out:
- open->op_delegate_type = flag;
- if (flag == NFS4_OPEN_DELEGATE_NONE) {
- if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
- open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
- dprintk("NFSD: WARNING: refusing delegation reclaim\n");
-
- /* 4.1 client asking for a delegation? */
- if (open->op_deleg_want)
- nfsd4_open_deleg_none_ext(open, status);
- }
+ open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
return;
out_free:
unhash_stid(&dp->dl_stid);
nfs4_put_delegation(dp);
out_no_deleg:
- flag = NFS4_OPEN_DELEGATE_NONE;
- goto out;
+ open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE;
+ if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
+ open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
+ dprintk("NFSD: WARNING: refusing delegation reclaim\n");
+
+ /* 4.1 client asking for a delegation? */
+ if (open->op_deleg_want)
+ nfsd4_open_deleg_none_ext(open, status);
+ return;
}
static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates
2013-05-21 20:25 ` J. Bruce Fields
@ 2013-05-22 16:20 ` J. Bruce Fields
0 siblings, 0 replies; 7+ messages in thread
From: J. Bruce Fields @ 2013-05-22 16:20 UTC (permalink / raw)
To: Steve Dickson; +Cc: Bruce Fields, Linux NFS Mailing list
On Tue, May 21, 2013 at 04:25:41PM -0400, J. Bruce Fields wrote:
> On Tue, May 21, 2013 at 03:23:38PM -0400, bfields wrote:
> > On Wed, May 15, 2013 at 02:51:49PM -0400, Steve Dickson wrote:
> > > When an exclusive create is done with the mode bits
> > > set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
> >
> > so implicitly O_RDONLY. Is that common? Maybe so, OK.
> >
> > > causes a OPEN op followed by a SETATTR op. When a
> > > read delegation is given in the OPEN, it causes
> > > the SETATTR to delay with EAGAIN until the
> > > delegation is recalled.
> > >
> > > This patch caused exclusive creates to give out
> > > a write delegation (which turn into no delegation)
> > > which allows the SETATTR seamlessly succeed.
> >
> > OK. May as well make it apply to all creates, though, I think?
> > Any create flag seems like a sign the file's likely to be modified soon,
> > hence isn't a good candidate for a read delegation.
>
> That would look like the following.
Note some 4.1 pynfs delegation tests depend on read-only create opens to
get delegations.
I've pushed out a pynfs change to
git://linux-nfs.org/~bfields/linux.git
to make pynfs reopen if it doesn't get a delegation on the create. Of
course there's no way pynfs can force the server to give the client a
delegation, so we just make our best effort.
For knfsd arguably the better solution would be to teach it not to break
a client's own read delegations. But I haven't looked into how to do
that. (And I'd need to review what the spec says in this case. And it
might not work for 4.0 if that SETATTR isn't being done with a stateid.)
--b.
>
> --b.
>
> commit 3f47b6220ca6b08a7ab86baaaab87389707a3308
> Author: Steve Dickson <steved@redhat.com>
> Date: Wed May 15 14:51:49 2013 -0400
>
> NFSD: Don't give out read delegations on exclusive creates
>
> When an exclusive create is done with the mode bits
> set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this
> causes a OPEN op followed by a SETATTR op. When a
> read delegation is given in the OPEN, it causes
> the SETATTR to delay with EAGAIN until the
> delegation is recalled.
>
> This patch caused exclusive creates to give out
> a write delegation (which turn into no delegation)
> which allows the SETATTR seamlessly succeed.
>
> Signed-off-by: Steve Dickson <steved@redhat.com>
> [bfields: do this for any CREATE, not just exclusive; comment]
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index c4f6339..44dcea9 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -3113,8 +3113,17 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
> goto out;
> if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
> goto out;
> + /*
> + * Also, if the file was opened for write or
> + * create, there's a good chance the client's
> + * about to write to it, resulting in an
> + * immediate recall (since we don't support
> + * write delegations):
> + */
> if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
> flag = NFS4_OPEN_DELEGATE_WRITE;
> + else if (open->op_create == NFS4_OPEN_CREATE)
> + flag = NFS4_OPEN_DELEGATE_WRITE;
> else
> flag = NFS4_OPEN_DELEGATE_READ;
> break;
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2013-05-22 16:20 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-05-15 18:51 [PATCH] NFSD: Don't give out read delegations on exclusive creates Steve Dickson
2013-05-21 18:43 ` Steve Dickson
2013-05-21 18:52 ` J. Bruce Fields
2013-05-21 19:23 ` J. Bruce Fields
2013-05-21 20:25 ` J. Bruce Fields
2013-05-22 16:20 ` J. Bruce Fields
2013-05-21 20:26 ` J. Bruce Fields
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