Commit 18d98f6c authored by Sachin Bhamare's avatar Sachin Bhamare Committed by Trond Myklebust

pnfs-obj: autologin: Add support for protocol autologin

The pnfs-objects protocol mandates that we autologin into devices not
present in the system, according to information specified in the
get_device_info returned from the server.

The Protocol specifies two login hints.
1. An IP address:port combination
2. A string URI which is constructed as a URL with a protocol prefix
   followed by :// and a string as address. For each  protocol prefix
   the string-address format might be different.

We only support the second option. The first option is just redundant
to the second one.
NOTE: The Kernel part of autologin does not parse the URI string. It
just channels it to a user-mode script. So any new login protocols should
only update the user-mode script which is a part of the nfs-utils package,
but the Kernel need not change.

We implement the autologin by using the call_usermodehelper() API.
(Thanks to Steve Dickson <steved@redhat.com> for pointing it out)
So there is no running daemon needed, and/or special setup.

We Add the osd_login_prog Kernel module parameters which defaults to:
	/sbin/osd_login

Kernel try's to upcall the program specified in osd_login_prog. If the file is
not found or the execution fails Kernel will disable any farther upcalls, by
zeroing out  osd_login_prog, Until Admin re-enables it by setting the
osd_login_prog parameter to a proper program.

Also add text about the osd_login program command line API to:
	Documentation/filesystems/nfs/pnfs.txt
and documentation of the new  osd_login_prog  module parameter to:
	Documentation/kernel-parameters.txt

TODO: Add timeout option in the case osd_login program gets
              stuck
Signed-off-by: default avatarSachin Bhamare <sbhamare@panasas.com>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent c6bfa1a1
......@@ -53,3 +53,57 @@ lseg maintains an extra reference corresponding to the NFS_LSEG_VALID
bit which holds it in the pnfs_layout_hdr's list. When the final lseg
is removed from the pnfs_layout_hdr's list, the NFS_LAYOUT_DESTROYED
bit is set, preventing any new lsegs from being added.
layout drivers
--------------
PNFS utilizes what is called layout drivers. The STD defines 3 basic
layout types: "files" "objects" and "blocks". For each of these types
there is a layout-driver with a common function-vectors table which
are called by the nfs-client pnfs-core to implement the different layout
types.
Files-layout-driver code is in: fs/nfs/nfs4filelayout.c && nfs4filelayoutdev.c
Objects-layout-deriver code is in: fs/nfs/objlayout/.. directory
Blocks-layout-deriver code is in: fs/nfs/blocklayout/.. directory
objects-layout setup
--------------------
As part of the full STD implementation the objlayoutdriver.ko needs, at times,
to automatically login to yet undiscovered iscsi/osd devices. For this the
driver makes up-calles to a user-mode script called *osd_login*
The path_name of the script to use is by default:
/sbin/osd_login.
This name can be overridden by the Kernel module parameter:
objlayoutdriver.osd_login_prog
If Kernel does not find the osd_login_prog path it will zero it out
and will not attempt farther logins. An admin can then write new value
to the objlayoutdriver.osd_login_prog Kernel parameter to re-enable it.
The /sbin/osd_login is part of the nfs-utils package, and should usually
be installed on distributions that support this Kernel version.
The API to the login script is as follows:
Usage: $0 -u <URI> -o <OSDNAME> -s <SYSTEMID>
Options:
-u target uri e.g. iscsi://<ip>:<port>
(allways exists)
(More protocols can be defined in the future.
The client does not interpret this string it is
passed unchanged as recieved from the Server)
-o osdname of the requested target OSD
(Might be empty)
(A string which denotes the OSD name, there is a
limit of 64 chars on this string)
-s systemid of the requested target OSD
(Might be empty)
(This string, if not empty is always an hex
representation of the 20 bytes osd_system_id)
blocks-layout setup
-------------------
TODO: Document the setup needs of the blocks layout driver
......@@ -1687,6 +1687,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
information.
objlayoutdriver.osd_login_prog=
[NFS] [OBJLAYOUT] sets the pathname to the program which
is used to automatically discover and login into new
osd-targets. Please see:
Documentation/filesystems/pnfs.txt for more explanations
nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
when a NMI is triggered.
Format: [state][,regs][,debounce][,die]
......
......@@ -137,6 +137,7 @@ static int objio_devices_lookup(struct pnfs_layout_hdr *pnfslay,
struct objio_dev_ent *ode;
struct osd_dev *od;
struct osd_dev_info odi;
bool retry_flag = true;
int err;
ode = _dev_list_find(NFS_SERVER(pnfslay->plh_inode), d_id);
......@@ -171,10 +172,18 @@ static int objio_devices_lookup(struct pnfs_layout_hdr *pnfslay,
goto out;
}
retry_lookup:
od = osduld_info_lookup(&odi);
if (unlikely(IS_ERR(od))) {
err = PTR_ERR(od);
dprintk("%s: osduld_info_lookup => %d\n", __func__, err);
if (err == -ENODEV && retry_flag) {
err = objlayout_autologin(deviceaddr);
if (likely(!err)) {
retry_flag = false;
goto retry_lookup;
}
}
goto out;
}
......
......@@ -37,6 +37,9 @@
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/kmod.h>
#include <linux/moduleparam.h>
#include <linux/ratelimit.h>
#include <scsi/osd_initiator.h>
#include "objlayout.h"
......@@ -651,3 +654,134 @@ void objlayout_put_deviceinfo(struct pnfs_osd_deviceaddr *deviceaddr)
__free_page(odi->page);
kfree(odi);
}
enum {
OBJLAYOUT_MAX_URI_LEN = 256, OBJLAYOUT_MAX_OSDNAME_LEN = 64,
OBJLAYOUT_MAX_SYSID_HEX_LEN = OSD_SYSTEMID_LEN * 2 + 1,
OSD_LOGIN_UPCALL_PATHLEN = 256
};
static char osd_login_prog[OSD_LOGIN_UPCALL_PATHLEN] = "/sbin/osd_login";
module_param_string(osd_login_prog, osd_login_prog, sizeof(osd_login_prog),
0600);
MODULE_PARM_DESC(osd_login_prog, "Path to the osd_login upcall program");
struct __auto_login {
char uri[OBJLAYOUT_MAX_URI_LEN];
char osdname[OBJLAYOUT_MAX_OSDNAME_LEN];
char systemid_hex[OBJLAYOUT_MAX_SYSID_HEX_LEN];
};
static int __objlayout_upcall(struct __auto_login *login)
{
static char *envp[] = { "HOME=/",
"TERM=linux",
"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
NULL
};
char *argv[8];
int ret;
if (unlikely(!osd_login_prog[0])) {
dprintk("%s: osd_login_prog is disabled\n", __func__);
return -EACCES;
}
dprintk("%s uri: %s\n", __func__, login->uri);
dprintk("%s osdname %s\n", __func__, login->osdname);
dprintk("%s systemid_hex %s\n", __func__, login->systemid_hex);
argv[0] = (char *)osd_login_prog;
argv[1] = "-u";
argv[2] = login->uri;
argv[3] = "-o";
argv[4] = login->osdname;
argv[5] = "-s";
argv[6] = login->systemid_hex;
argv[7] = NULL;
ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
/*
* Disable the upcall mechanism if we're getting an ENOENT or
* EACCES error. The admin can re-enable it on the fly by using
* sysfs to set the objlayoutdriver.osd_login_prog module parameter once
* the problem has been fixed.
*/
if (ret == -ENOENT || ret == -EACCES) {
printk(KERN_ERR "PNFS-OBJ: %s was not found please set "
"objlayoutdriver.osd_login_prog kernel parameter!\n",
osd_login_prog);
osd_login_prog[0] = '\0';
}
dprintk("%s %s return value: %d\n", __func__, osd_login_prog, ret);
return ret;
}
/* Assume dest is all zeros */
static void __copy_nfsS_and_zero_terminate(struct nfs4_string s,
char *dest, int max_len,
const char *var_name)
{
if (!s.len)
return;
if (s.len >= max_len) {
pr_warn_ratelimited(
"objlayout_autologin: %s: s.len(%d) >= max_len(%d)",
var_name, s.len, max_len);
s.len = max_len - 1; /* space for null terminator */
}
memcpy(dest, s.data, s.len);
}
/* Assume sysid is all zeros */
static void _sysid_2_hex(struct nfs4_string s,
char sysid[OBJLAYOUT_MAX_SYSID_HEX_LEN])
{
int i;
char *cur;
if (!s.len)
return;
if (s.len != OSD_SYSTEMID_LEN) {
pr_warn_ratelimited(
"objlayout_autologin: systemid_len(%d) != OSD_SYSTEMID_LEN",
s.len);
if (s.len > OSD_SYSTEMID_LEN)
s.len = OSD_SYSTEMID_LEN;
}
cur = sysid;
for (i = 0; i < s.len; i++)
cur = hex_byte_pack(cur, s.data[i]);
}
int objlayout_autologin(struct pnfs_osd_deviceaddr *deviceaddr)
{
int rc;
struct __auto_login login;
if (!deviceaddr->oda_targetaddr.ota_netaddr.r_addr.len)
return -ENODEV;
memset(&login, 0, sizeof(login));
__copy_nfsS_and_zero_terminate(
deviceaddr->oda_targetaddr.ota_netaddr.r_addr,
login.uri, sizeof(login.uri), "URI");
__copy_nfsS_and_zero_terminate(
deviceaddr->oda_osdname,
login.osdname, sizeof(login.osdname), "OSDNAME");
_sysid_2_hex(deviceaddr->oda_systemid, login.systemid_hex);
rc = __objlayout_upcall(&login);
if (rc > 0) /* script returns positive values */
rc = -ENODEV;
return rc;
}
......@@ -184,4 +184,6 @@ extern void objlayout_encode_layoutreturn(
struct xdr_stream *,
const struct nfs4_layoutreturn_args *);
extern int objlayout_autologin(struct pnfs_osd_deviceaddr *deviceaddr);
#endif /* _OBJLAYOUT_H */
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