On Tue, Nov 29, 2011 at 9:13 PM, Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx> wrote: > 29.11.2011 16:40, tao.peng@xxxxxxx пишет: > >>> -----Original Message----- >>> From: Stanislav Kinsbursky [mailto:skinsbursky@xxxxxxxxxxxxx] >>> Sent: Tuesday, November 29, 2011 8:19 PM >>> To: Peng, Tao >>> Cc: Trond.Myklebust@xxxxxxxxxx; linux-nfs@xxxxxxxxxxxxxxx; Pavel >>> Emelianov; neilb@xxxxxxx; >>> netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; James Bottomley; >>> bfields@xxxxxxxxxxxx; >>> davem@xxxxxxxxxxxxx; devel@xxxxxxxxxx >>> Subject: Re: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference >>> from blocklayout routines >>> >>> 29.11.2011 16:00, tao.peng@xxxxxxx пишет: >>>>> >>>>> -----Original Message----- >>>>> From: linux-nfs-owner@xxxxxxxxxxxxxxx >>>>> [mailto:linux-nfs-owner@xxxxxxxxxxxxxxx] On Behalf Of >>> >>> Stanislav >>>>> >>>>> Kinsbursky >>>>> Sent: Tuesday, November 29, 2011 6:11 PM >>>>> To: Trond.Myklebust@xxxxxxxxxx >>>>> Cc: linux-nfs@xxxxxxxxxxxxxxx; xemul@xxxxxxxxxxxxx; neilb@xxxxxxx; >>>>> netdev@xxxxxxxxxxxxxxx; linux- >>>>> kernel@xxxxxxxxxxxxxxx; jbottomley@xxxxxxxxxxxxx; bfields@xxxxxxxxxxxx; >>>>> davem@xxxxxxxxxxxxx; >>>>> devel@xxxxxxxxxx >>>>> Subject: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference from >>>>> blocklayout routines >>>>> >>>>> This is a cleanup patch. We don't need this reference anymore, because >>>>> blocklayout pipes dentries now creates and destroys in per-net >>>>> operations and >>>>> on PipeFS mount/umount notification. >>>>> Note that nfs4blocklayout_register_net() now returns 0 instead of >>>>> -ENOENT in >>>>> case of PipeFS superblock absence. This is ok, because blocklayout pipe >>>>> dentry >>>>> will be created on PipeFS mount event. >>>> >>>> When is the "pipefs mount event" going to happen? When inserting kernel >>>> modules or when user issues >>> >>> mount command? >>>> >>>> >>> >>> When user issues mount command. >>> Kernel mounts of PipeFS has been removed with all these patch sets I've >>> sent >>> already. >> >> Then it is going to break blocklayout user space program blkmapd, which is >> stared before mounting any file system and it tries to open the pipe file >> when started. > > > Sorry, but I don't get it. Probably we have misunderstanding here. > You said, that "blkmapd ... tries to open the pipe file when started". This > pipe file is located on PipeFS, isn't it? > If yes, then PipeFS have to be mounted already in user-space. And if it has > been mounted - then pipe dentry is present. > IOW, pipe (without dentry) will be created on module load. Pipe dentry will > be created right after that (like it was before) if PipeFS was mounted from > user-space. If not - then pipe dentry will be created on PipeFS (!) mount > (not NFS or pNFS mount) from user-space. Sorry, I misunderstood. I was thinking about mounting NFS or pNFS when you say "when user issues mount command". Thanks for the explanation. Regards, Tao > > Or I'm missing something in your reply? > > >> Not sure if you implement the same logic on nfs pipe as well. But if you >> do, then nfs client user space program idmapd will fail to start for the >> same reason. >> > > The same logic here. > > >> Why not just fail to load module if you fail to initialize pipefs? When is >> rpc_get_sb_net() going to fail? >> > > Sorry, but I don't understand, what is your idea. And why do we need to fail > at all. > BTW, rpc_get_sb_net() just checks, was PipeFS mounted in passed net, or not. > If not - not a problem. Dentries will be created on mount event. If yes, > then it returns locked PipeFS sb and the next step is dentry creation. > > >>> >>> >>>> Thanks, >>>> Tao >>>> >>>>> >>>>> Signed-off-by: Stanislav Kinsbursky<skinsbursky@xxxxxxxxxxxxx> >>>>> >>>>> --- >>>>> fs/nfs/blocklayout/blocklayout.c | 9 +-------- >>>>> 1 files changed, 1 insertions(+), 8 deletions(-) >>>>> >>>>> diff --git a/fs/nfs/blocklayout/blocklayout.c >>>>> b/fs/nfs/blocklayout/blocklayout.c >>>>> index acf7ac9..8211ffd 100644 >>>>> --- a/fs/nfs/blocklayout/blocklayout.c >>>>> +++ b/fs/nfs/blocklayout/blocklayout.c >>>>> @@ -1032,7 +1032,7 @@ static struct dentry >>>>> *nfs4blocklayout_register_net(struct net *net, >>>>> >>>>> pipefs_sb = rpc_get_sb_net(net); >>>>> if (!pipefs_sb) >>>>> - return ERR_PTR(-ENOENT); >>>>> + return 0; >>>>> dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe); >>>>> rpc_put_sb_net(net); >>>>> return dentry; >>>>> @@ -1083,7 +1083,6 @@ static struct pernet_operations >>>>> nfs4blocklayout_net_ops = { >>>>> >>>>> static int __init nfs4blocklayout_init(void) >>>>> { >>>>> - struct vfsmount *mnt; >>>>> int ret; >>>>> >>>>> dprintk("%s: NFSv4 Block Layout Driver Registering...\n", >>>>> __func__); >>>>> @@ -1093,12 +1092,6 @@ static int __init nfs4blocklayout_init(void) >>>>> goto out; >>>>> >>>>> init_waitqueue_head(&bl_wq); >>>>> - >>>>> - mnt = rpc_get_mount(); >>>>> - if (IS_ERR(mnt)) { >>>>> - ret = PTR_ERR(mnt); >>>>> - goto out_remove; >>>>> - } >>>>> ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block); >>>>> if (ret) >>>>> goto out_remove; >>>>> >>>>> -- >>>>> 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 >>>> >>>> >>> >>> >>> -- >>> Best regards, >>> Stanislav Kinsbursky >> >> > > > -- > Best regards, > Stanislav Kinsbursky > -- > 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 -- 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
