On Wed, 2012-03-07 at 00:19 +0000, Myklebust, Trond wrote: > On Wed, 2012-02-29 at 18:59 +0400, Stanislav Kinsbursky wrote: > > Today, there is a problem in connecting of local SUNRPC thansports. These > > transports uses UNIX sockets and connection itself is done by rpciod > > workqueue. > > But UNIX sockets lookup is done in context of process file system root. I.e. > > all local thunsports are connecting in rpciod context. > > This works nice until we will try to mount NFS from process with other root > > - > > for example in container. This container can have it's own (nested) root and > > rcpbind process, listening on it's own unix sockets. But NFS mount attempt > > in > > this container will register new service (Lockd for example) in global > > rpcbind > > - not containers's one. > > This patch solves the problem by switching rpciod kernel thread's file > > system > > root to right one (stored on transport) while connecting of local > > transports. > > > > Signed-off-by: Stanislav Kinsbursky <[email protected]> > > > > --- > > fs/fs_struct.c | 1 + > > net/sunrpc/xprtsock.c | 32 ++++++++++++++++++++++++++++++-- > > 2 files changed, 31 insertions(+), 2 deletions(-) > > > > diff --git a/fs/fs_struct.c b/fs/fs_struct.c > > index 78b519c..0f984c3 100644 > > --- a/fs/fs_struct.c > > +++ b/fs/fs_struct.c > > @@ -36,6 +36,7 @@ void set_fs_root(struct fs_struct *fs, struct path *path) > > if (old_root.dentry) > > path_put_longterm(&old_root); > > } > > +EXPORT_SYMBOL_GPL(set_fs_root); > > > > /* > > * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values. > > diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c > > index 4c8281d..c94c181 100644 > > --- a/net/sunrpc/xprtsock.c > > +++ b/net/sunrpc/xprtsock.c > > @@ -37,6 +37,7 @@ > > #include <linux/sunrpc/svcsock.h> > > #include <linux/sunrpc/xprtsock.h> > > #include <linux/file.h> > > +#include <linux/fs_struct.h> > > #ifdef CONFIG_SUNRPC_BACKCHANNEL > > #include <linux/sunrpc/bc_xprt.h> > > #endif > > @@ -255,6 +256,11 @@ struct sock_xprt { > > void (*old_state_change)(struct sock *); > > void (*old_write_space)(struct sock *); > > void (*old_error_report)(struct sock *); > > + > > + /* > > + * Saved transport creator root. Required for local transports only. > > + */ > > + struct path root; > > }; > > > > /* > > @@ -1891,6 +1897,7 @@ static void xs_local_setup_socket(struct work_struct > > *work) > > struct rpc_xprt *xprt = &transport->xprt; > > struct socket *sock; > > int status = -EIO; > > + struct path root; > > > > if (xprt->shutdown) > > goto out; > > @@ -1908,7 +1915,14 @@ static void xs_local_setup_socket(struct work_struct > > *work) > > dprintk("RPC: worker connecting xprt %p via AF_LOCAL to %s\n", > > xprt, xprt->address_strings[RPC_DISPLAY_ADDR]); > > > > + get_fs_root(current->fs, &root); > > + set_fs_root(current->fs, &transport->root); > > + > > status = xs_local_finish_connecting(xprt, sock); > > + > > + set_fs_root(current->fs, &root); > > + path_put(&root); > > + > > switch (status) { > > case 0: > > Hi Stanislav, > > What happens here if the mount namespace of the process that originally > created the sock_xprt no longer exists? Should we care about that case? > > Cheers > Trond
BTW: We will in any case need Al Viro and Christoph's ACK in order to export the set_fs_root() function. -- Trond Myklebust Linux NFS client maintainer NetApp [email protected] www.netapp.com _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
