On May 24, 2010, at 2:20 PM, Boaz Harrosh wrote:
On 05/24/2010 08:25 PM, William A. (Andy) Adamson wrote:
On Mon, May 24, 2010 at 12:02 PM, Tao Guo <glorioustao@xxxxxxxxx>
wrote:
On Mon, May 24, 2010 at 9:43 PM, William A. (Andy) Adamson
<androsadamson@xxxxxxxxx> wrote:
On Mon, May 24, 2010 at 2:37 AM, Tao Guo <glorioustao@xxxxxxxxx>
wrote:
I see... But what if sync == 1? At that time, data must have
already
been freed, so you should not use data->cred anymore.
Agreed.
Since LAYOUTCOMMIT is not called after close, we can get rid of
taking
the reference all together since a reference is taken on OPEN and
dropped on CLOSE.
I forgot memory mapped files where writes can occur after the close,
and so layoutcommit can also occur after the close. So, I will keep
the get_rpccred in pnfs_need_layout commit and resend this patch with
the put_rpccred in the layoutcommit done routine.
Andy I get hangs on:
data->is_sync = sync;
status = pnfs4_proc_layoutcommit(data);
+ put_rpccred(data->cred);
with sync==1 like Tao Guo said
could you send the updated patch?
On it's way
Boaz
-->Andy
I agree. However that will change several functions' interface I
guess.
I still have a question: why some procedures need to set rpc_cred
whereas some needn't ? what is the connection between ctx's rpc_cred
and nfs4_state_owner's so_cred? Any guidance will be appreciated...
Here's my take on an answer...
If an rpc_cred is not specified in the rpc_msg then the fsuid, fsgid,
and group info toe the current_cred is used to lookup an rpc_cred.
RPC's can be sent from several tasks - rpciod vrs the application
task
for example. OPEN, CLOSE, LOCK, UNLOCK, READ, WRITE (and memmapped
I/O) should all be sent with the credential that opened the file. So,
in order to ensure this the nfs4_state_owner->so_cred is used for
these compounds even if the task is rpciod with root fsuid/fsgid. The
nfs_open_context rpc_cred is the nfs4_state_owner so_cred. The
nfs_open_context can exist longer than the nfs4_state_owner.
I think LAYOUTCOMMIT also wants to use the credential that did the
I/O
- not for the file layout driver which doesn't care, but for the
object and block layout drivers that use the layout as a lock and
where a permissions check (?) is done on LAYOUTCOMMIT.
Currently, LAYOUTGET and LAYOUTRETURN don't set the rpc_cred. This is
because the layout can last past opens and closes. If we ever want to
support EXCHGID4_FLAG_BIND_PRINC_STATEID we will need to remember the
cred and set it for these calls.
-->Andy
--
tao.
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tao.
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