On Sun, Jan 04, 2009 at 09:53:12AM +0800, wengang wang wrote:
> Hi,
> Finally, how about this patch?
> for this problem, the solution is either to fix HPUX or to fix linux.
> are we going to fix linux?
>
> any comment is appreciated.
On my list, sorry, I just haven't gotten to it--bug me again if I
haven't dealt with it by the end of the week.--b.
>
> thanks,
> wengang.
>
> wengang wang wrote:
>> please ignore the email sent from wwg@xxxxxxxxxx and reply to this post
>> if you will.
>> thanks.
>>
>> sometimes HPUX nfs client sends a create request to linux nfs server(v2/v3).
>> the dump of the request is like:
>> obj_attributes
>> mode: value follows
>> set_it: value follows (1)
>> mode: 00
>> uid: no value
>> set_it: no value (0)
>> gid: value follows
>> set_it: value follows (1)
>> gid: 8030
>> size: value follows
>> set_it: value follows (1)
>> size: 0
>> atime: don't change
>> set_it: don't change (0)
>> mtime: don't change
>> set_it: don't change (0)
>>
>> note that mode is 00(havs no rwx privilege even for the owner) and it requires
>> to set size to 0.
>>
>> as current nfsd(v2/v3) implementation, the server does mainly 2 steps:
>> 1) creates the file in mode specified by calling vfs_create().
>> 2) sets attributes for the file by calling nfsd_setattr().
>>
>> at step 2), it finally calls file system specific setattr() function which may
>> fails when checking permission because changing size needs WRITE privilege but
>> it has no since mode is 000.
>>
>> for this case, a new file created, we may simply ignore the request of setting
>> size to 0. so that the WRITE privilege is not needed and finally success.
>>
>> the patch is based on 2.6.27.10.
>>
>> Signed-off-by: Wengang Wang <wen.gang.wang@xxxxxxxxxx>
>> --
>> vfs.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>> diff -up ./fs/nfsd/vfs.c.orig ./fs/nfsd/vfs.c
>> --- ./fs/nfsd/vfs.c.orig 2008-12-23 14:11:14.000000000 +0800
>> +++ ./fs/nfsd/vfs.c 2008-12-23 14:54:16.000000000 +0800
>> @@ -1268,6 +1268,16 @@ nfsd_create(struct svc_rqst *rqstp, stru
>> switch (type) {
>> case S_IFREG:
>> host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
>> + /* HPUX client sometimes creates a file in mode 000, and set
>> + * size to 0. setting size to 0 may fail for some spcific + * file
>> systems by the permission checking which requires
>> + * WRITE privilege but the mode is 000.
>> + * we ignore setting size to 0 for the creation, since it's
>> + * just 0 after created.
>> + * */
>> + if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
>> + iap->ia_valid &= ~ATTR_SIZE;
>> +
>> break;
>> case S_IFDIR:
>> host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
>> @@ -1421,6 +1431,16 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
>> /* setattr will sync the child (or not) */
>> }
>> + /* HPUX client sometimes creates a file in mode 000, and set size to
>> 0.
>> + * setting size to 0 may fail for some spcific file systems by the
>> + * permission checking which requires WRITE privilege but the mode is
>> + * 000.
>> + * we ignore setting size to 0 for the creation, since it's just 0
>> + * after created.
>> + * */
>> + if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
>> + iap->ia_valid &= ~ATTR_SIZE;
>> +
>> if (createmode == NFS3_CREATE_EXCLUSIVE) {
>> /* Cram the verifier into atime/mtime */
>> iap->ia_valid = ATTR_MTIME|ATTR_ATIME
>> --
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