J. Bruce Fields :
> On Fri, Jan 14, 2011 at 04:21:53PM +0800, Mi Jinlong wrote:
>>
>> J. Bruce Fields:
>>> Any change to any of the links pointing to an entry should also break
>>> delegations.
>>>
>>> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>>> ---
>>> fs/nfsd/vfs.c | 27 +++++++++++++++++++++++----
>>> 1 files changed, 23 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
>>> index 839ed88..f31321a 100644
>>> --- a/fs/nfsd/vfs.c
>>> +++ b/fs/nfsd/vfs.c
>>> @@ -272,6 +272,13 @@ out:
>>> return err;
>>> }
>>>
>>> +static int nfsd_break_lease(struct inode *inode)
>>> +{
>>> + if (!S_ISREG(inode->i_mode))
>>> + return 0;
>>> + return break_lease(inode, O_WRONLY | O_NONBLOCK);
>> Hi Bruce,
>>
>> break_lease will return -EWOULDBLOCK here if break success, not 0.
>> at __break_lease:
>>
>> 1193 */
>> 1194 int __break_lease(struct inode *inode, unsigned int mode)
>> 1195 {
>> ... ...
>> 1253 if (i_have_this_lease || (mode & O_NONBLOCK)) {
>> 1254 error = -EWOULDBLOCK;
>> 1255 goto out;
>> 1256 }
>> ... ...
>> 1283 out:
>> 1284 unlock_flocks();
>> 1285 if (!IS_ERR(new_fl))
>> 1286 locks_free_lock(new_fl);
>> 1287 return error;
>> 1288 }
>>
>> If we just return the error -EWOULDBLOCK (which mapped to -EAGAIN) at
>> nfsd_break_lease(), the NFS request will be drop for -EAGAIN is mapped
>> to nfserr_dropit at nfserrno().
>
> See my for-2.6.38-incoming branch (especially 062304a815fe and
> surrounding). I was getting tired of needing special handling for
> EAGAIN and EWOULDBLOCK, so I removed that mapping and am setting a flag
> on the rqstp instead to indicate the need to drop a request.
>
> Does that look reasonable to you?
I'm sorry for missing those patch you have post before,
I just test the two patch at v2.6.37. ^_^
Those patch is great.
According to the discussing before, after the two patch for breaking delegation,
a race as you said "
One problem is that there's a race: nothing I can see stops anyone from
getting another lease after may_delete() but before the delete happens."
also exist here. We can't make sure that a new delegation don't be granted
between nfsd_break_lease() and unlink file complete or rename complete.
---
thanks
Mi Jinlong
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