On 2011-07-25 15:13, Trond Myklebust wrote: > On Wed, 2011-07-20 at 01:52 -0400, tao.peng@xxxxxxx wrote: >> Hi, Trond, >> >> Any comments on this patch? I still get kernel crash when pnfs write is attempted but fails and calls pnfs_ld_write_done(). It seems object layout uses the same code path as well. But I don't find the patch in either your tree or Benny's tree. Are there any concerns? >> >> Thanks, >> Tao > > The whole pnfs_ld_write_done thing is bogus and needs to be replaced > with something sane. It is trying to initiate a WRITE RPC call with the > wrong block size, I was under the impression that your re-coalesce work will take care of that. Is there anything else that needs to be done? > and is calling the MDS rpc_call_done() and > rpc_release() with an uninitialised rpc task pointer. So on this path there is indeed no active rpc task so we're using the task structure in the struct nfs_write_data. I agree that having a helper function at the rpc layer to initialize it to a meaningful value indicating there is no active rpc task would be a useful thing. But the fix Peng sent is for the fallback path where we initiate I/O to the MDS and we do build a rpc task properly. On this path lseg indeed needs to be put and set to NULL. Benny > > Ditto for pnfs_ld_read_done. > > Cheers > Trond > >>> -----Original Message----- >>> From: Benny Halevy [mailto:bhalevy@xxxxxxxxxx] >>> Sent: Saturday, July 09, 2011 10:10 PM >>> To: Peng Tao >>> Cc: Trond.Myklebust@xxxxxxxxxx; linux-nfs@xxxxxxxxxxxxxxx; Peng, Tao >>> Subject: Re: [PATCH] NFS41: Drop lseg ref before fallthru to MDS >>> >>> On 2011-07-04 04:30, Peng Tao wrote: >>>> There is no need to keep lseg reference when read/write through MDS. >>>> This fixes a null pointer crash at nfs_post_op_update_inode_force_wcc >>>> because nfs4_proc_write_setup will unset wdata->res.fattr if wdata->lseg >>>> is not NULL. >>>> >>>> Signed-off-by: Peng Tao <peng_tao@xxxxxxx> >>> >>> Looks good to me. >>> >>> Benny >>> >>>> --- >>>> fs/nfs/pnfs.c | 6 ++++++ >>>> 1 files changed, 6 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c >>>> index 30a0394..55fdf02 100644 >>>> --- a/fs/nfs/pnfs.c >>>> +++ b/fs/nfs/pnfs.c >>>> @@ -1193,6 +1193,9 @@ pnfs_ld_write_done(struct nfs_write_data *data) >>>> >>>> dprintk("%s: pnfs_error=%d, retry via MDS\n", __func__, >>>> data->pnfs_error); >>>> + >>>> + put_lseg(data->lseg); >>>> + data->lseg = NULL; >>>> status = nfs_initiate_write(data, NFS_CLIENT(data->inode), >>>> data->mds_ops, NFS_FILE_SYNC); >>>> return status ? : -EAGAIN; >>>> @@ -1240,6 +1243,9 @@ pnfs_ld_read_done(struct nfs_read_data *data) >>>> >>>> dprintk("%s: pnfs_error=%d, retry via MDS\n", __func__, >>>> data->pnfs_error); >>>> + >>>> + put_lseg(data->lseg); >>>> + data->lseg = NULL; >>>> status = nfs_initiate_read(data, NFS_CLIENT(data->inode), >>>> data->mds_ops); >>>> return status ? : -EAGAIN; >> > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
