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NFSv4: Fix a race in the net namespace mount notification

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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 <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
This commit is contained in:
Trond Myklebust 2012-05-23 13:24:36 -04:00
parent 7b38c3682c
commit 4697bd5e94
3 changed files with 29 additions and 3 deletions
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16
fs/nfs/client.c
View File

@ -507,6 +507,17 @@ 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));
}
/*
* Found an existing client. Make sure it's ready before returning.
*/
@ -516,8 +527,7 @@ nfs_found_client(const struct nfs_client_initdata *cl_init,
{
int error;
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);
@ -1333,7 +1343,7 @@ 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 */

15
fs/nfs/idmap.c
View File

@ -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;

1
fs/nfs/internal.h
View File

@ -168,6 +168,7 @@ 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,