2018-07-20 18:15:37

by Olga Kornievskaia

[permalink] [raw]
Subject: sending duplicate GETATTRs

Hi Trond,

I would some help understanding attributes management.

Right now, any time a directory inode that was marked with
INVALID_ACCESS (say to a change_attribute changed) ends up triggering
sending a duplicate GETATTR. I don't think that's correct.

In nfs_execute_ok() we check if (nfs_check_cache_invalid(inode,
NFS_INO_INVALID_ACCESS)) and the call __nfs_revalidate_inode() which
will trigger GETATTR. I don't understand why after calling this
function the INVALID_ACCESS doesn't get cleared? Because that's what
causes the double GETATTR to be sent.

On the open path, the first time the getattr is sent is in

Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 [nfsv4]
Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 [nfs]
Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
Jul 19 15:39:52 ipa18 kernel: link_path_walk+0x29d/0x520
Jul 19 15:39:52 ipa18 kernel: path_openat+0xf6/0x1230
Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
Jul 19 15:39:52 ipa18 kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9

And then again during the open

Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 [nfsv4]
Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 [nfs]
Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
Jul 19 15:39:52 ipa18 kernel: path_openat+0x942/0x1230
Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
Jul 19 15:39:52 ipa18 kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9

Can't we remove INVALID_ACCESS after we revalidated the inode? This
removes the duplicated GETATTRs. Is this a valid way of fixing this
issue?

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 8f8e9e9..2b55a45 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2504,6 +2504,8 @@ static int nfs_execute_ok(struct inode *inode, int mask)
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
ret = __nfs_revalidate_inode(server, inode);
+ if (!ret)
+ NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_ACCESS;
}
if (ret == 0 && !execute_ok(inode))
ret = -EACCES;


2018-07-20 18:55:13

by Trond Myklebust

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

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2018-07-20 19:06:46

by Olga Kornievskaia

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

On Fri, Jul 20, 2018 at 2:05 PM, Trond Myklebust
<[email protected]> wrote:
> On Fri, 2018-07-20 at 13:26 -0400, Olga Kornievskaia wrote:
>> Hi Trond,
>>
>> I would some help understanding attributes management.
>>
>> Right now, any time a directory inode that was marked with
>> INVALID_ACCESS (say to a change_attribute changed) ends up triggering
>> sending a duplicate GETATTR. I don't think that's correct.
>>
>> In nfs_execute_ok() we check if (nfs_check_cache_invalid(inode,
>> NFS_INO_INVALID_ACCESS)) and the call __nfs_revalidate_inode() which
>> will trigger GETATTR. I don't understand why after calling this
>> function the INVALID_ACCESS doesn't get cleared? Because that's what
>> causes the double GETATTR to be sent.
>>
>> On the open path, the first time the getattr is sent is in
>>
>> Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>> Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 [nfsv4]
>> Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 [nfs]
>> Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
>> Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>> Jul 19 15:39:52 ipa18 kernel: link_path_walk+0x29d/0x520
>> Jul 19 15:39:52 ipa18 kernel: path_openat+0xf6/0x1230
>> Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>> Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>> Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>> Jul 19 15:39:52 ipa18 kernel:
>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>
>> And then again during the open
>>
>> Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>> Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 [nfsv4]
>> Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 [nfs]
>> Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
>> Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>> Jul 19 15:39:52 ipa18 kernel: path_openat+0x942/0x1230
>> Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>> Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>> Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>> Jul 19 15:39:52 ipa18 kernel:
>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>
>> Can't we remove INVALID_ACCESS after we revalidated the inode? This
>> removes the duplicated GETATTRs. Is this a valid way of fixing this
>> issue?
>>
>> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>> index 8f8e9e9..2b55a45 100644
>> --- a/fs/nfs/dir.c
>> +++ b/fs/nfs/dir.c
>> @@ -2504,6 +2504,8 @@ static int nfs_execute_ok(struct inode *inode,
>> int mask)
>> if (mask & MAY_NOT_BLOCK)
>> return -ECHILD;
>> ret = __nfs_revalidate_inode(server, inode);
>> + if (!ret)
>> + NFS_I(inode)->cache_validity &=
>> ~NFS_INO_INVALID_ACCESS;
>> }
>> if (ret == 0 && !execute_ok(inode))
>> ret = -EACCES;
>
>
> I don't see how the above makes sense.
>
> Either the attribute revalidation confirmed that the change attr, mode
> + uid + gid are unchanged, in which case the call to
> nfs_refresh_inode() during revalidation will fail to set
> NFS_INO_INVALID_ACCESS, or it confirmed that at least one of them has
> changed, in which case we do want to revalidate the access cache.

I'm confused as to against what are we checking then?

We flagged a directory inode to have invalid attributes. So we sent a
GETATTR. I would think that after getting the result all our
attributes should be valid. Why would a client as the next operation
send another GETATTR for the same inode?

>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> [email protected]
>

2018-07-20 19:30:22

by Olga Kornievskaia

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

On Fri, Jul 20, 2018 at 2:17 PM, Olga Kornievskaia <[email protected]> wrote:
> On Fri, Jul 20, 2018 at 2:05 PM, Trond Myklebust
> <[email protected]> wrote:
>> On Fri, 2018-07-20 at 13:26 -0400, Olga Kornievskaia wrote:
>>> Hi Trond,
>>>
>>> I would some help understanding attributes management.
>>>
>>> Right now, any time a directory inode that was marked with
>>> INVALID_ACCESS (say to a change_attribute changed) ends up triggering
>>> sending a duplicate GETATTR. I don't think that's correct.
>>>
>>> In nfs_execute_ok() we check if (nfs_check_cache_invalid(inode,
>>> NFS_INO_INVALID_ACCESS)) and the call __nfs_revalidate_inode() which
>>> will trigger GETATTR. I don't understand why after calling this
>>> function the INVALID_ACCESS doesn't get cleared? Because that's what
>>> causes the double GETATTR to be sent.
>>>
>>> On the open path, the first time the getattr is sent is in
>>>
>>> Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>>> Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 [nfsv4]
>>> Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 [nfs]
>>> Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
>>> Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>>> Jul 19 15:39:52 ipa18 kernel: link_path_walk+0x29d/0x520
>>> Jul 19 15:39:52 ipa18 kernel: path_openat+0xf6/0x1230
>>> Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>>> Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>>> Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>>> Jul 19 15:39:52 ipa18 kernel:
>>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>>
>>> And then again during the open
>>>
>>> Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>>> Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 [nfsv4]
>>> Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 [nfs]
>>> Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
>>> Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>>> Jul 19 15:39:52 ipa18 kernel: path_openat+0x942/0x1230
>>> Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>>> Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>>> Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>>> Jul 19 15:39:52 ipa18 kernel:
>>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>>
>>> Can't we remove INVALID_ACCESS after we revalidated the inode? This
>>> removes the duplicated GETATTRs. Is this a valid way of fixing this
>>> issue?
>>>
>>> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>>> index 8f8e9e9..2b55a45 100644
>>> --- a/fs/nfs/dir.c
>>> +++ b/fs/nfs/dir.c
>>> @@ -2504,6 +2504,8 @@ static int nfs_execute_ok(struct inode *inode,
>>> int mask)
>>> if (mask & MAY_NOT_BLOCK)
>>> return -ECHILD;
>>> ret = __nfs_revalidate_inode(server, inode);
>>> + if (!ret)
>>> + NFS_I(inode)->cache_validity &=
>>> ~NFS_INO_INVALID_ACCESS;
>>> }
>>> if (ret == 0 && !execute_ok(inode))
>>> ret = -EACCES;
>>
>>
>> I don't see how the above makes sense.
>>
>> Either the attribute revalidation confirmed that the change attr, mode
>> + uid + gid are unchanged, in which case the call to
>> nfs_refresh_inode() during revalidation will fail to set
>> NFS_INO_INVALID_ACCESS, or it confirmed that at least one of them has
>> changed, in which case we do want to revalidate the access cache.
>
> I'm confused as to against what are we checking then?
>
> We flagged a directory inode to have invalid attributes. So we sent a
> GETATTR. I would think that after getting the result all our
> attributes should be valid. Why would a client as the next operation
> send another GETATTR for the same inode?
>

I didn't answer your question but rather explained what I see client do.

Let's me see if I can try again:
in nfs_execute_ok() the check for the INVALID_CACHE is true so the
code calls __nfs_revalidate_inode() which ends up sending a GETATTR.
Could it be that what's happening is that GETATTRs reply for the
change_attr is different than what we have stored. BUT that's obvious,
we knew that to begin with since we are validating the attributes. So
we update it and then we send another GETATTR now the GETATTR sends
back the "same" change_attr and this time it matches what we have
stored. Why is this 2nd GETATTR necessary? The attribute should be
marked as valid after a getting a successful GETATTR.

>>
>> --
>> Trond Myklebust
>> Linux NFS client maintainer, Hammerspace
>> [email protected]
>>

2018-07-20 19:33:37

by Trond Myklebust

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

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d3cuaGFtbWVyLnNwYWNlDQoNCg==

2018-07-20 19:36:34

by Trond Myklebust

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

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2018-07-20 19:48:11

by Olga Kornievskaia

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

On Fri, Jul 20, 2018 at 2:46 PM, Trond Myklebust
<[email protected]> wrote:
> On Fri, 2018-07-20 at 14:40 -0400, Olga Kornievskaia wrote:
>> On Fri, Jul 20, 2018 at 2:17 PM, Olga Kornievskaia <[email protected]>
>> wrote:
>> > On Fri, Jul 20, 2018 at 2:05 PM, Trond Myklebust
>> > <[email protected]> wrote:
>> > > On Fri, 2018-07-20 at 13:26 -0400, Olga Kornievskaia wrote:
>> > > > Hi Trond,
>> > > >
>> > > > I would some help understanding attributes management.
>> > > >
>> > > > Right now, any time a directory inode that was marked with
>> > > > INVALID_ACCESS (say to a change_attribute changed) ends up
>> > > > triggering
>> > > > sending a duplicate GETATTR. I don't think that's correct.
>> > > >
>> > > > In nfs_execute_ok() we check if (nfs_check_cache_invalid(inode,
>> > > > NFS_INO_INVALID_ACCESS)) and the call __nfs_revalidate_inode()
>> > > > which
>> > > > will trigger GETATTR. I don't understand why after calling this
>> > > > function the INVALID_ACCESS doesn't get cleared? Because that's
>> > > > what
>> > > > causes the double GETATTR to be sent.
>> > > >
>> > > > On the open path, the first time the getattr is sent is in
>> > > >
>> > > > Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>> > > > Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110
>> > > > [nfsv4]
>> > > > Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370
>> > > > [nfs]
>> > > > Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
>> > > > Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>> > > > Jul 19 15:39:52 ipa18 kernel: link_path_walk+0x29d/0x520
>> > > > Jul 19 15:39:52 ipa18 kernel: path_openat+0xf6/0x1230
>> > > > Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>> > > > Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>> > > > Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>> > > > Jul 19 15:39:52 ipa18 kernel:
>> > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> > > >
>> > > > And then again during the open
>> > > >
>> > > > Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>> > > > Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110
>> > > > [nfsv4]
>> > > > Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370
>> > > > [nfs]
>> > > > Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs]
>> > > > Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>> > > > Jul 19 15:39:52 ipa18 kernel: path_openat+0x942/0x1230
>> > > > Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>> > > > Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>> > > > Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>> > > > Jul 19 15:39:52 ipa18 kernel:
>> > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> > > >
>> > > > Can't we remove INVALID_ACCESS after we revalidated the inode?
>> > > > This
>> > > > removes the duplicated GETATTRs. Is this a valid way of fixing
>> > > > this
>> > > > issue?
>> > > >
>> > > > diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>> > > > index 8f8e9e9..2b55a45 100644
>> > > > --- a/fs/nfs/dir.c
>> > > > +++ b/fs/nfs/dir.c
>> > > > @@ -2504,6 +2504,8 @@ static int nfs_execute_ok(struct inode
>> > > > *inode,
>> > > > int mask)
>> > > > if (mask & MAY_NOT_BLOCK)
>> > > > return -ECHILD;
>> > > > ret = __nfs_revalidate_inode(server, inode);
>> > > > + if (!ret)
>> > > > + NFS_I(inode)->cache_validity &=
>> > > > ~NFS_INO_INVALID_ACCESS;
>> > > > }
>> > > > if (ret == 0 && !execute_ok(inode))
>> > > > ret = -EACCES;
>> > >
>> > >
>> > > I don't see how the above makes sense.
>> > >
>> > > Either the attribute revalidation confirmed that the change attr,
>> > > mode
>> > > + uid + gid are unchanged, in which case the call to
>> > > nfs_refresh_inode() during revalidation will fail to set
>> > > NFS_INO_INVALID_ACCESS, or it confirmed that at least one of them
>> > > has
>> > > changed, in which case we do want to revalidate the access cache.
>> >
>> > I'm confused as to against what are we checking then?
>> >
>> > We flagged a directory inode to have invalid attributes. So we sent
>> > a
>> > GETATTR. I would think that after getting the result all our
>> > attributes should be valid. Why would a client as the next
>> > operation
>> > send another GETATTR for the same inode?
>> >
>>
>> I didn't answer your question but rather explained what I see client
>> do.
>>
>> Let's me see if I can try again:
>> in nfs_execute_ok() the check for the INVALID_CACHE is true so the
>> code calls __nfs_revalidate_inode() which ends up sending a GETATTR.
>> Could it be that what's happening is that GETATTRs reply for the
>> change_attr is different than what we have stored. BUT that's
>> obvious,
>> we knew that to begin with since we are validating the attributes. So
>> we update it and then we send another GETATTR now the GETATTR sends
>> back the "same" change_attr and this time it matches what we have
>> stored. Why is this 2nd GETATTR necessary? The attribute should be
>> marked as valid after a getting a successful GETATTR.
>>
> Oh... I see what you are saying. Yes, that check looks like it should
> be looking for NFS_INO_INVALID_OTHER.

Whew. ok I'm glad something make sense. However, you lost me on
"NFS_INO_INVALID_OTHER". What does that flag means?
Are you talking about checking the check in nfs_execute_ok() to check
for INVALID_OTHER instead of INVALID_ACCESS?

>
> --
> Trond Myklebust
> CTO, Hammerspace Inc
> 4300 El Camino Real, Suite 105
> Los Altos, CA 94022
> http://www.hammer.space

2018-07-20 20:11:29

by Trond Myklebust

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

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2018-07-20 20:38:22

by Olga Kornievskaia

[permalink] [raw]
Subject: Re: sending duplicate GETATTRs

On Fri, Jul 20, 2018 at 3:19 PM, Trond Myklebust
<[email protected]> wrote:
> On Fri, 2018-07-20 at 14:58 -0400, Olga Kornievskaia wrote:
>> On Fri, Jul 20, 2018 at 2:46 PM, Trond Myklebust
>> <[email protected]> wrote:
>> > On Fri, 2018-07-20 at 14:40 -0400, Olga Kornievskaia wrote:
>> > > On Fri, Jul 20, 2018 at 2:17 PM, Olga Kornievskaia <[email protected]
>> > > u>
>> > > wrote:
>> > > > On Fri, Jul 20, 2018 at 2:05 PM, Trond Myklebust
>> > > > <[email protected]> wrote:
>> > > > > On Fri, 2018-07-20 at 13:26 -0400, Olga Kornievskaia wrote:
>> > > > > > Hi Trond,
>> > > > > >
>> > > > > > I would some help understanding attributes management.
>> > > > > >
>> > > > > > Right now, any time a directory inode that was marked with
>> > > > > > INVALID_ACCESS (say to a change_attribute changed) ends up
>> > > > > > triggering
>> > > > > > sending a duplicate GETATTR. I don't think that's correct.
>> > > > > >
>> > > > > > In nfs_execute_ok() we check if
>> > > > > > (nfs_check_cache_invalid(inode,
>> > > > > > NFS_INO_INVALID_ACCESS)) and the call
>> > > > > > __nfs_revalidate_inode()
>> > > > > > which
>> > > > > > will trigger GETATTR. I don't understand why after calling
>> > > > > > this
>> > > > > > function the INVALID_ACCESS doesn't get cleared? Because
>> > > > > > that's
>> > > > > > what
>> > > > > > causes the double GETATTR to be sent.
>> > > > > >
>> > > > > > On the open path, the first time the getattr is sent is in
>> > > > > >
>> > > > > > Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>> > > > > > Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110
>> > > > > > [nfsv4]
>> > > > > > Jul 19 15:39:52 ipa18 kernel:
>> > > > > > __nfs_revalidate_inode+0xe1/0x370
>> > > > > > [nfs]
>> > > > > > Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0
>> > > > > > [nfs]
>> > > > > > Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>> > > > > > Jul 19 15:39:52 ipa18 kernel: link_path_walk+0x29d/0x520
>> > > > > > Jul 19 15:39:52 ipa18 kernel: path_openat+0xf6/0x1230
>> > > > > > Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>> > > > > > Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>> > > > > > Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>> > > > > > Jul 19 15:39:52 ipa18 kernel:
>> > > > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> > > > > >
>> > > > > > And then again during the open
>> > > > > >
>> > > > > > Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73
>> > > > > > Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110
>> > > > > > [nfsv4]
>> > > > > > Jul 19 15:39:52 ipa18 kernel:
>> > > > > > __nfs_revalidate_inode+0xe1/0x370
>> > > > > > [nfs]
>> > > > > > Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0
>> > > > > > [nfs]
>> > > > > > Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130
>> > > > > > Jul 19 15:39:52 ipa18 kernel: path_openat+0x942/0x1230
>> > > > > > Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100
>> > > > > > Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210
>> > > > > > Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180
>> > > > > > Jul 19 15:39:52 ipa18 kernel:
>> > > > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> > > > > >
>> > > > > > Can't we remove INVALID_ACCESS after we revalidated the
>> > > > > > inode?
>> > > > > > This
>> > > > > > removes the duplicated GETATTRs. Is this a valid way of
>> > > > > > fixing
>> > > > > > this
>> > > > > > issue?
>> > > > > >
>> > > > > > diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>> > > > > > index 8f8e9e9..2b55a45 100644
>> > > > > > --- a/fs/nfs/dir.c
>> > > > > > +++ b/fs/nfs/dir.c
>> > > > > > @@ -2504,6 +2504,8 @@ static int nfs_execute_ok(struct
>> > > > > > inode
>> > > > > > *inode,
>> > > > > > int mask)
>> > > > > > if (mask & MAY_NOT_BLOCK)
>> > > > > > return -ECHILD;
>> > > > > > ret = __nfs_revalidate_inode(server,
>> > > > > > inode);
>> > > > > > + if (!ret)
>> > > > > > + NFS_I(inode)->cache_validity &=
>> > > > > > ~NFS_INO_INVALID_ACCESS;
>> > > > > > }
>> > > > > > if (ret == 0 && !execute_ok(inode))
>> > > > > > ret = -EACCES;
>> > > > >
>> > > > >
>> > > > > I don't see how the above makes sense.
>> > > > >
>> > > > > Either the attribute revalidation confirmed that the change
>> > > > > attr,
>> > > > > mode
>> > > > > + uid + gid are unchanged, in which case the call to
>> > > > > nfs_refresh_inode() during revalidation will fail to set
>> > > > > NFS_INO_INVALID_ACCESS, or it confirmed that at least one of
>> > > > > them
>> > > > > has
>> > > > > changed, in which case we do want to revalidate the access
>> > > > > cache.
>> > > >
>> > > > I'm confused as to against what are we checking then?
>> > > >
>> > > > We flagged a directory inode to have invalid attributes. So we
>> > > > sent
>> > > > a
>> > > > GETATTR. I would think that after getting the result all our
>> > > > attributes should be valid. Why would a client as the next
>> > > > operation
>> > > > send another GETATTR for the same inode?
>> > > >
>> > >
>> > > I didn't answer your question but rather explained what I see
>> > > client
>> > > do.
>> > >
>> > > Let's me see if I can try again:
>> > > in nfs_execute_ok() the check for the INVALID_CACHE is true so
>> > > the
>> > > code calls __nfs_revalidate_inode() which ends up sending a
>> > > GETATTR.
>> > > Could it be that what's happening is that GETATTRs reply for the
>> > > change_attr is different than what we have stored. BUT that's
>> > > obvious,
>> > > we knew that to begin with since we are validating the
>> > > attributes. So
>> > > we update it and then we send another GETATTR now the GETATTR
>> > > sends
>> > > back the "same" change_attr and this time it matches what we have
>> > > stored. Why is this 2nd GETATTR necessary? The attribute should
>> > > be
>> > > marked as valid after a getting a successful GETATTR.
>> > >
>> >
>> > Oh... I see what you are saying. Yes, that check looks like it
>> > should
>> > be looking for NFS_INO_INVALID_OTHER.
>>
>> Whew. ok I'm glad something make sense. However, you lost me on
>> "NFS_INO_INVALID_OTHER". What does that flag means?
>> Are you talking about checking the check in nfs_execute_ok() to check
>> for INVALID_OTHER instead of INVALID_ACCESS?
>>
>
> I'm saying that function should probably read as:
>
> static int nfs_execute_ok(struct inode *inode, int mask)
> {
> struct nfs_server *server = NFS_SERVER(inode);
> int ret = 0;
>
> if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_OTHER)) {
> if (mask & MAY_NOT_BLOCK)
> return -ECHILD;
> ret = __nfs_revalidate_inode(server, inode);
> }
> if (ret == 0 && !execute_ok(inode))
> ret = -EACCES;
> return ret;
> }
>

With that change I also don't see a 2nd GETATTR sent. Would you mind
creating a patch for it?