Revision 35991652baa12ff3d0e420c0d0cb2ad9f7076e5b authored by Mikulas Patocka on 02 June 2012, 23:29:58 UTC, committed by Alasdair G Kergon on 02 June 2012, 23:29:58 UTC
After the failure of a group of paths, any alternative paths that need initialising do not become available until further I/O is sent to the device. Until this has happened, ioctls return -EAGAIN. With this patch, new paths are made available in response to an ioctl too. The processing of the ioctl gets delayed until this has happened. Instead of returning an error, we submit a work item to kmultipathd (that will potentially activate the new path) and retry in ten milliseconds. Note that the patch doesn't retry an ioctl if the ioctl itself fails due to a path failure. Such retries should be handled intelligently by the code that generated the ioctl in the first place, noting that some SCSI commands should not be retried because they are not idempotent (XOR write commands). For commands that could be retried, there is a danger that if the device rejected the SCSI command, the path could be errorneously marked as failed, and the request would be retried on another path which might fail too. It can be determined if the failure happens on the device or on the SCSI controller, but there is no guarantee that all SCSI drivers set these flags correctly. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 parent f220fd4
auth_unix.c
/*
* linux/net/sunrpc/auth_unix.c
*
* UNIX-style authentication; no AUTH_SHORT support
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/auth.h>
#define NFS_NGROUPS 16
struct unx_cred {
struct rpc_cred uc_base;
gid_t uc_gid;
gid_t uc_gids[NFS_NGROUPS];
};
#define uc_uid uc_base.cr_uid
#define UNX_WRITESLACK (21 + (UNX_MAXNODENAME >> 2))
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static struct rpc_auth unix_auth;
static const struct rpc_credops unix_credops;
static struct rpc_auth *
unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
{
dprintk("RPC: creating UNIX authenticator for client %p\n",
clnt);
atomic_inc(&unix_auth.au_count);
return &unix_auth;
}
static void
unx_destroy(struct rpc_auth *auth)
{
dprintk("RPC: destroying UNIX authenticator %p\n", auth);
rpcauth_clear_credcache(auth->au_credcache);
}
/*
* Lookup AUTH_UNIX creds for current process
*/
static struct rpc_cred *
unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
return rpcauth_lookup_credcache(auth, acred, flags);
}
static struct rpc_cred *
unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
struct unx_cred *cred;
unsigned int groups = 0;
unsigned int i;
dprintk("RPC: allocating UNIX cred for uid %d gid %d\n",
acred->uid, acred->gid);
if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
return ERR_PTR(-ENOMEM);
rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
if (acred->group_info != NULL)
groups = acred->group_info->ngroups;
if (groups > NFS_NGROUPS)
groups = NFS_NGROUPS;
cred->uc_gid = acred->gid;
for (i = 0; i < groups; i++)
cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
if (i < NFS_NGROUPS)
cred->uc_gids[i] = NOGROUP;
return &cred->uc_base;
}
static void
unx_free_cred(struct unx_cred *unx_cred)
{
dprintk("RPC: unx_free_cred %p\n", unx_cred);
kfree(unx_cred);
}
static void
unx_free_cred_callback(struct rcu_head *head)
{
struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
unx_free_cred(unx_cred);
}
static void
unx_destroy_cred(struct rpc_cred *cred)
{
call_rcu(&cred->cr_rcu, unx_free_cred_callback);
}
/*
* Match credentials against current process creds.
* The root_override argument takes care of cases where the caller may
* request root creds (e.g. for NFS swapping).
*/
static int
unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
{
struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
unsigned int groups = 0;
unsigned int i;
if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid)
return 0;
if (acred->group_info != NULL)
groups = acred->group_info->ngroups;
if (groups > NFS_NGROUPS)
groups = NFS_NGROUPS;
for (i = 0; i < groups ; i++)
if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
return 0;
if (groups < NFS_NGROUPS &&
cred->uc_gids[groups] != NOGROUP)
return 0;
return 1;
}
/*
* Marshal credentials.
* Maybe we should keep a cached credential for performance reasons.
*/
static __be32 *
unx_marshal(struct rpc_task *task, __be32 *p)
{
struct rpc_clnt *clnt = task->tk_client;
struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
__be32 *base, *hold;
int i;
*p++ = htonl(RPC_AUTH_UNIX);
base = p++;
*p++ = htonl(jiffies/HZ);
/*
* Copy the UTS nodename captured when the client was created.
*/
p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
*p++ = htonl((u32) cred->uc_uid);
*p++ = htonl((u32) cred->uc_gid);
hold = p++;
for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
*p++ = htonl((u32) cred->uc_gids[i]);
*hold = htonl(p - hold - 1); /* gid array length */
*base = htonl((p - base - 1) << 2); /* cred length */
*p++ = htonl(RPC_AUTH_NULL);
*p++ = htonl(0);
return p;
}
/*
* Refresh credentials. This is a no-op for AUTH_UNIX
*/
static int
unx_refresh(struct rpc_task *task)
{
set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
return 0;
}
static __be32 *
unx_validate(struct rpc_task *task, __be32 *p)
{
rpc_authflavor_t flavor;
u32 size;
flavor = ntohl(*p++);
if (flavor != RPC_AUTH_NULL &&
flavor != RPC_AUTH_UNIX &&
flavor != RPC_AUTH_SHORT) {
printk("RPC: bad verf flavor: %u\n", flavor);
return NULL;
}
size = ntohl(*p++);
if (size > RPC_MAX_AUTH_SIZE) {
printk("RPC: giant verf size: %u\n", size);
return NULL;
}
task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
p += (size >> 2);
return p;
}
int __init rpc_init_authunix(void)
{
return rpcauth_init_credcache(&unix_auth);
}
void rpc_destroy_authunix(void)
{
rpcauth_destroy_credcache(&unix_auth);
}
const struct rpc_authops authunix_ops = {
.owner = THIS_MODULE,
.au_flavor = RPC_AUTH_UNIX,
.au_name = "UNIX",
.create = unx_create,
.destroy = unx_destroy,
.lookup_cred = unx_lookup_cred,
.crcreate = unx_create_cred,
};
static
struct rpc_auth unix_auth = {
.au_cslack = UNX_WRITESLACK,
.au_rslack = 2, /* assume AUTH_NULL verf */
.au_ops = &authunix_ops,
.au_flavor = RPC_AUTH_UNIX,
.au_count = ATOMIC_INIT(0),
};
static
const struct rpc_credops unix_credops = {
.cr_name = "AUTH_UNIX",
.crdestroy = unx_destroy_cred,
.crbind = rpcauth_generic_bind_cred,
.crmatch = unx_match,
.crmarshal = unx_marshal,
.crrefresh = unx_refresh,
.crvalidate = unx_validate,
};
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