Return-Path: linux-nfs-owner@vger.kernel.org Received: from relay.parallels.com ([195.214.232.42]:41057 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933793Ab2EWS7U convert rfc822-to-8bit (ORCPT ); Wed, 23 May 2012 14:59:20 -0400 Message-ID: <4FBD3371.1070109@parallels.com> Date: Wed, 23 May 2012 22:58:57 +0400 From: Stanislav Kinsbursky MIME-Version: 1.0 To: Trond Myklebust CC: "linux-nfs@vger.kernel.org" Subject: Re: [PATCH 2/3] NFSv4: Fix a race in the net namespace mount notification References: <1337794363-11905-1-git-send-email-Trond.Myklebust@netapp.com> <1337794363-11905-2-git-send-email-Trond.Myklebust@netapp.com> In-Reply-To: <1337794363-11905-2-git-send-email-Trond.Myklebust@netapp.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: Looks good to me. Acked-by: Stanislav Kinsbursky 23.05.2012 21:32, Trond Myklebust написал: > Since the struct nfs_client gets added to the global nfs_client_list > before it is initialised, it is possible that rpc_pipefs_event can > end up trying to create idmapper entries on such a thing. > > The solution is to have the mount notification wait for the > initialisation of each nfs_client to complete, and then to > skip any entries for which the it failed. > > Reported-by: Stanislav Kinsbursky > Signed-off-by: Trond Myklebust > Cc: Stanislav Kinsbursky > --- > fs/nfs/client.c | 16 +++++++++++++--- > fs/nfs/idmap.c | 15 +++++++++++++++ > fs/nfs/internal.h | 1 + > 3 files changed, 29 insertions(+), 3 deletions(-) > > diff --git a/fs/nfs/client.c b/fs/nfs/client.c > index 78970a1..e6070ea 100644 > --- a/fs/nfs/client.c > +++ b/fs/nfs/client.c > @@ -504,6 +504,17 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat > return NULL; > } > > +static bool nfs_client_init_is_complete(const struct nfs_client *clp) > +{ > + return clp->cl_cons_state != NFS_CS_INITING; > +} > + > +int nfs_wait_client_init_complete(const struct nfs_client *clp) > +{ > + return wait_event_killable(nfs_client_active_wq, > + nfs_client_init_is_complete(clp)); > +} > + > /* > * Look up a client by IP address and protocol version > * - creates a new record if one doesn't yet exist > @@ -564,8 +575,7 @@ found_client: > if (new) > nfs_free_client(new); > > - error = wait_event_killable(nfs_client_active_wq, > - clp->cl_cons_state< NFS_CS_INITING); > + error = nfs_wait_client_init_complete(clp); > if (error< 0) { > nfs_put_client(clp); > return ERR_PTR(-ERESTARTSYS); > @@ -1317,7 +1327,7 @@ static int nfs4_init_client_minor_version(struct nfs_client *clp) > * so that the client back channel can find the > * nfs_client struct > */ > - clp->cl_cons_state = NFS_CS_SESSION_INITING; > + nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING); > } > #endif /* CONFIG_NFS_V4_1 */ > > diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c > index 3e8edbe..6ca949b 100644 > --- a/fs/nfs/idmap.c > +++ b/fs/nfs/idmap.c > @@ -530,9 +530,24 @@ static struct nfs_client *nfs_get_client_for_event(struct net *net, int event) > struct nfs_net *nn = net_generic(net, nfs_net_id); > struct dentry *cl_dentry; > struct nfs_client *clp; > + int err; > > +restart: > spin_lock(&nn->nfs_client_lock); > list_for_each_entry(clp,&nn->nfs_client_list, cl_share_link) { > + /* Wait for initialisation to finish */ > + if (clp->cl_cons_state == NFS_CS_INITING) { > + atomic_inc(&clp->cl_count); > + spin_unlock(&nn->nfs_client_lock); > + err = nfs_wait_client_init_complete(clp); > + nfs_put_client(clp); > + if (err) > + return NULL; > + goto restart; > + } > + /* Skip nfs_clients that failed to initialise */ > + if (clp->cl_cons_state< 0) > + continue; > if (clp->rpc_ops !=&nfs_v4_clientops) > continue; > cl_dentry = clp->cl_idmap->idmap_pipe->dentry; > diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h > index 00b66de..a23daa9 100644 > --- a/fs/nfs/internal.h > +++ b/fs/nfs/internal.h > @@ -167,6 +167,7 @@ extern struct nfs_server *nfs_clone_server(struct nfs_server *, > struct nfs_fh *, > struct nfs_fattr *, > rpc_authflavor_t); > +extern int nfs_wait_client_init_complete(const struct nfs_client *clp); > extern void nfs_mark_client_ready(struct nfs_client *clp, int state); > extern struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp, > const struct sockaddr *ds_addr,