commit 9523feac27 upstream.
Because userspace gets Very Unhappy when calls like stat() and execve()
return -EINTR on 9p filesystem mounts. For instance, when bash is
looking in PATH for things to execute and some SIGCHLD interrupts
stat(), bash can throw a spurious 'command not found' since it doesn't
retry the stat().
In practice, hitting the problem is rare and needs a really
slow/bogged down 9p server.
Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes the following sparse warnings:
net/9p/trans_xen.c:528:5: warning:
symbol 'p9_trans_xen_init' was not declared. Should it be static?
net/9p/trans_xen.c:540:6: warning:
symbol 'p9_trans_xen_exit' was not declared. Should it be static?
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
In case of error, the function xenbus_read() returns ERR_PTR() and never
returns NULL. The NULL test in the return value check should be replaced
with IS_ERR().
Fixes: 71ebd71921 ("xen/9pfs: connect to the backend")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
In order to use "len" to check for xenbus_read errors properly, we need
to initialize len to 0 before passing it to xenbus_read.
CC: dan.carpenter@oracle.com
CC: jgross@suse.com
CC: boris.ostrovsky@oracle.com
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Upon receiving a notification from the backend, schedule the
p9_xen_response work_struct. p9_xen_response checks if any responses are
available, if so, it reads them one by one, calling p9_client_cb to send
them up to the 9p layer (p9_client_cb completes the request). Handle the
ring following the Xen 9pfs specification.
CC: groug@kaod.org
CC: jgross@suse.com
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Implement struct p9_trans_module create and close functions by looking
at the available Xen 9pfs frontend-backend connections. We don't expect
many frontend-backend connections, thus walking a list is OK.
Send requests to the backend by copying each request to one of the
available rings (each frontend-backend connection comes with multiple
rings). Handle the ring and notifications following the 9pfs
specification. If there are not enough free bytes on the ring for the
request, wait on the wait_queue: the backend will send a notification
after consuming more requests.
CC: groug@kaod.org
CC: jgross@suse.com
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Implement functions to handle the xenbus handshake. Upon connection,
allocate the rings according to the protocol specification.
Initialize a work_struct and a wait_queue. The work_struct will be used
to schedule work upon receiving an event channel notification from the
backend. The wait_queue will be used to wait when the ring is full and
we need to send a new request.
CC: groug@kaod.org
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Introduce the Xen 9pfs transport driver: add struct xenbus_driver to
register as a xenbus driver and add struct p9_trans_module to register
as v9fs driver.
All functions are empty stubs for now.
CC: groug@kaod.org
CC: jgross@suse.com
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tomas Bortoli