RPC: rpciod waiting on sync task!

RPC: rpciod waiting on sync task!

[Dima Brodsky]

Hi,

I modified the linux NFS client, kernel 2.4.5 and 2.4.6-pre7, to send
an extra SETATTR, with special values, within nfs_open and nfs_release
so that I would be able to track file open and close.  For the server I
am using a slightly modified linux user level nfs server.

What I noticed is that after this change I get:

RPC: rpciod waiting on sync task!

coming from the kernel under heavy read load, especially with
larger chunks of data 8k, 16, and 64k.

The code introduced into nfs_open and nfs_release is:

        memset( &fattr, 0, sizeof(struct nfs_fattr) );
        memset( &attr, 0, sizeof(struct iattr) );

        attr.ia_valid = ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_SIZE;
        attr.ia_mode = inode->i_mode;
        attr.ia_uid = -10;
        attr.ia_gid = -10;
        attr.ia_size = -10;
        attr.ia_atime = -1;
        attr.ia_mtime = -1;
        attr.ia_ctime = -1;
        attr.ia_attr_flags = -1;

        error = NFS_PROTO(inode)->setattr(inode, &fattr, &attr);
        if ( error ) {
                printk( "nfs_network_openclose: error=%d\n", error );
        }

Does anybody see any problems with this code?  The unmodified nfs client
works fine with the unmodified nfs server.

Thanks
ttyl
Dima

-- 
Dima Brodsky                                   dima@cs.ubc.ca
                                               http://www.cs.ubc.ca/~dima
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Computers are like Old Testament gods; lots of rules and no mercy.
							  (Joseph Campbell)

Re: RPC: rpciod waiting on sync task!

[Trond Myklebust]

>>>>> " " == Dima Brodsky <dima@cs.ubc.ca> writes:

     > Hi, I modified the linux NFS client, kernel 2.4.5 and
     > 2.4.6-pre7, to send an extra SETATTR, with special values,
     > within nfs_open and nfs_release so that I would be able to
     > track file open and close.  For the server I am using a
     > slightly modified linux user level nfs server.

     > What I noticed is that after this change I get:

     > RPC: rpciod waiting on sync task!

That probably means that you've put this setattr code somewhere in the
rpciod read,write or delete callbacks.

You should never mix asynchronous and synchronous calls as this can
cause the rpciod task to deadlock by waiting on itself...

Cheers,
  Trond