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
xfrm_replay.c
/*
* xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
*
* Copyright (C) 2010 secunet Security Networks AG
* Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/export.h>
#include <net/xfrm.h>
u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
{
u32 seq, seq_hi, bottom;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
if (!(x->props.flags & XFRM_STATE_ESN))
return 0;
seq = ntohl(net_seq);
seq_hi = replay_esn->seq_hi;
bottom = replay_esn->seq - replay_esn->replay_window + 1;
if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
/* A. same subspace */
if (unlikely(seq < bottom))
seq_hi++;
} else {
/* B. window spans two subspaces */
if (unlikely(seq >= bottom))
seq_hi--;
}
return seq_hi;
}
static void xfrm_replay_notify(struct xfrm_state *x, int event)
{
struct km_event c;
/* we send notify messages in case
* 1. we updated on of the sequence numbers, and the seqno difference
* is at least x->replay_maxdiff, in this case we also update the
* timeout of our timer function
* 2. if x->replay_maxage has elapsed since last update,
* and there were changes
*
* The state structure must be locked!
*/
switch (event) {
case XFRM_REPLAY_UPDATE:
if (x->replay_maxdiff &&
(x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
(x->replay.oseq - x->preplay.oseq < x->replay_maxdiff)) {
if (x->xflags & XFRM_TIME_DEFER)
event = XFRM_REPLAY_TIMEOUT;
else
return;
}
break;
case XFRM_REPLAY_TIMEOUT:
if (memcmp(&x->replay, &x->preplay,
sizeof(struct xfrm_replay_state)) == 0) {
x->xflags |= XFRM_TIME_DEFER;
return;
}
break;
}
memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
c.event = XFRM_MSG_NEWAE;
c.data.aevent = event;
km_state_notify(x, &c);
if (x->replay_maxage &&
!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
x->xflags &= ~XFRM_TIME_DEFER;
}
static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
{
int err = 0;
struct net *net = xs_net(x);
if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
if (unlikely(x->replay.oseq == 0)) {
x->replay.oseq--;
xfrm_audit_state_replay_overflow(x, skb);
err = -EOVERFLOW;
return err;
}
if (xfrm_aevent_is_on(net))
x->repl->notify(x, XFRM_REPLAY_UPDATE);
}
return err;
}
static int xfrm_replay_check(struct xfrm_state *x,
struct sk_buff *skb, __be32 net_seq)
{
u32 diff;
u32 seq = ntohl(net_seq);
if (!x->props.replay_window)
return 0;
if (unlikely(seq == 0))
goto err;
if (likely(seq > x->replay.seq))
return 0;
diff = x->replay.seq - seq;
if (diff >= min_t(unsigned int, x->props.replay_window,
sizeof(x->replay.bitmap) * 8)) {
x->stats.replay_window++;
goto err;
}
if (x->replay.bitmap & (1U << diff)) {
x->stats.replay++;
goto err;
}
return 0;
err:
xfrm_audit_state_replay(x, skb, net_seq);
return -EINVAL;
}
static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
{
u32 diff;
u32 seq = ntohl(net_seq);
if (!x->props.replay_window)
return;
if (seq > x->replay.seq) {
diff = seq - x->replay.seq;
if (diff < x->props.replay_window)
x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
else
x->replay.bitmap = 1;
x->replay.seq = seq;
} else {
diff = x->replay.seq - seq;
x->replay.bitmap |= (1U << diff);
}
if (xfrm_aevent_is_on(xs_net(x)))
x->repl->notify(x, XFRM_REPLAY_UPDATE);
}
static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
{
int err = 0;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
struct net *net = xs_net(x);
if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
if (unlikely(replay_esn->oseq == 0)) {
replay_esn->oseq--;
xfrm_audit_state_replay_overflow(x, skb);
err = -EOVERFLOW;
return err;
}
if (xfrm_aevent_is_on(net))
x->repl->notify(x, XFRM_REPLAY_UPDATE);
}
return err;
}
static int xfrm_replay_check_bmp(struct xfrm_state *x,
struct sk_buff *skb, __be32 net_seq)
{
unsigned int bitnr, nr;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
u32 pos;
u32 seq = ntohl(net_seq);
u32 diff = replay_esn->seq - seq;
if (!replay_esn->replay_window)
return 0;
if (unlikely(seq == 0))
goto err;
if (likely(seq > replay_esn->seq))
return 0;
if (diff >= replay_esn->replay_window) {
x->stats.replay_window++;
goto err;
}
pos = (replay_esn->seq - 1) % replay_esn->replay_window;
if (pos >= diff)
bitnr = (pos - diff) % replay_esn->replay_window;
else
bitnr = replay_esn->replay_window - (diff - pos);
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
if (replay_esn->bmp[nr] & (1U << bitnr))
goto err_replay;
return 0;
err_replay:
x->stats.replay++;
err:
xfrm_audit_state_replay(x, skb, net_seq);
return -EINVAL;
}
static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
{
unsigned int bitnr, nr, i;
u32 diff;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
u32 seq = ntohl(net_seq);
u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
if (!replay_esn->replay_window)
return;
if (seq > replay_esn->seq) {
diff = seq - replay_esn->seq;
if (diff < replay_esn->replay_window) {
for (i = 1; i < diff; i++) {
bitnr = (pos + i) % replay_esn->replay_window;
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
replay_esn->bmp[nr] &= ~(1U << bitnr);
}
} else {
nr = (replay_esn->replay_window - 1) >> 5;
for (i = 0; i <= nr; i++)
replay_esn->bmp[i] = 0;
}
bitnr = (pos + diff) % replay_esn->replay_window;
replay_esn->seq = seq;
} else {
diff = replay_esn->seq - seq;
if (pos >= diff)
bitnr = (pos - diff) % replay_esn->replay_window;
else
bitnr = replay_esn->replay_window - (diff - pos);
}
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
replay_esn->bmp[nr] |= (1U << bitnr);
if (xfrm_aevent_is_on(xs_net(x)))
x->repl->notify(x, XFRM_REPLAY_UPDATE);
}
static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
{
struct km_event c;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
/* we send notify messages in case
* 1. we updated on of the sequence numbers, and the seqno difference
* is at least x->replay_maxdiff, in this case we also update the
* timeout of our timer function
* 2. if x->replay_maxage has elapsed since last update,
* and there were changes
*
* The state structure must be locked!
*/
switch (event) {
case XFRM_REPLAY_UPDATE:
if (x->replay_maxdiff &&
(replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
(replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
if (x->xflags & XFRM_TIME_DEFER)
event = XFRM_REPLAY_TIMEOUT;
else
return;
}
break;
case XFRM_REPLAY_TIMEOUT:
if (memcmp(x->replay_esn, x->preplay_esn,
xfrm_replay_state_esn_len(replay_esn)) == 0) {
x->xflags |= XFRM_TIME_DEFER;
return;
}
break;
}
memcpy(x->preplay_esn, x->replay_esn,
xfrm_replay_state_esn_len(replay_esn));
c.event = XFRM_MSG_NEWAE;
c.data.aevent = event;
km_state_notify(x, &c);
if (x->replay_maxage &&
!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
x->xflags &= ~XFRM_TIME_DEFER;
}
static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
{
int err = 0;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
struct net *net = xs_net(x);
if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
if (unlikely(replay_esn->oseq == 0)) {
XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
if (replay_esn->oseq_hi == 0) {
replay_esn->oseq--;
replay_esn->oseq_hi--;
xfrm_audit_state_replay_overflow(x, skb);
err = -EOVERFLOW;
return err;
}
}
if (xfrm_aevent_is_on(net))
x->repl->notify(x, XFRM_REPLAY_UPDATE);
}
return err;
}
static int xfrm_replay_check_esn(struct xfrm_state *x,
struct sk_buff *skb, __be32 net_seq)
{
unsigned int bitnr, nr;
u32 diff;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
u32 pos;
u32 seq = ntohl(net_seq);
u32 wsize = replay_esn->replay_window;
u32 top = replay_esn->seq;
u32 bottom = top - wsize + 1;
if (!wsize)
return 0;
if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
(replay_esn->seq < replay_esn->replay_window - 1)))
goto err;
diff = top - seq;
if (likely(top >= wsize - 1)) {
/* A. same subspace */
if (likely(seq > top) || seq < bottom)
return 0;
} else {
/* B. window spans two subspaces */
if (likely(seq > top && seq < bottom))
return 0;
if (seq >= bottom)
diff = ~seq + top + 1;
}
if (diff >= replay_esn->replay_window) {
x->stats.replay_window++;
goto err;
}
pos = (replay_esn->seq - 1) % replay_esn->replay_window;
if (pos >= diff)
bitnr = (pos - diff) % replay_esn->replay_window;
else
bitnr = replay_esn->replay_window - (diff - pos);
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
if (replay_esn->bmp[nr] & (1U << bitnr))
goto err_replay;
return 0;
err_replay:
x->stats.replay++;
err:
xfrm_audit_state_replay(x, skb, net_seq);
return -EINVAL;
}
static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
{
unsigned int bitnr, nr, i;
int wrap;
u32 diff, pos, seq, seq_hi;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
if (!replay_esn->replay_window)
return;
seq = ntohl(net_seq);
pos = (replay_esn->seq - 1) % replay_esn->replay_window;
seq_hi = xfrm_replay_seqhi(x, net_seq);
wrap = seq_hi - replay_esn->seq_hi;
if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
if (likely(!wrap))
diff = seq - replay_esn->seq;
else
diff = ~replay_esn->seq + seq + 1;
if (diff < replay_esn->replay_window) {
for (i = 1; i < diff; i++) {
bitnr = (pos + i) % replay_esn->replay_window;
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
replay_esn->bmp[nr] &= ~(1U << bitnr);
}
} else {
nr = (replay_esn->replay_window - 1) >> 5;
for (i = 0; i <= nr; i++)
replay_esn->bmp[i] = 0;
}
bitnr = (pos + diff) % replay_esn->replay_window;
replay_esn->seq = seq;
if (unlikely(wrap > 0))
replay_esn->seq_hi++;
} else {
diff = replay_esn->seq - seq;
if (pos >= diff)
bitnr = (pos - diff) % replay_esn->replay_window;
else
bitnr = replay_esn->replay_window - (diff - pos);
}
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
replay_esn->bmp[nr] |= (1U << bitnr);
if (xfrm_aevent_is_on(xs_net(x)))
x->repl->notify(x, XFRM_REPLAY_UPDATE);
}
static struct xfrm_replay xfrm_replay_legacy = {
.advance = xfrm_replay_advance,
.check = xfrm_replay_check,
.notify = xfrm_replay_notify,
.overflow = xfrm_replay_overflow,
};
static struct xfrm_replay xfrm_replay_bmp = {
.advance = xfrm_replay_advance_bmp,
.check = xfrm_replay_check_bmp,
.notify = xfrm_replay_notify_bmp,
.overflow = xfrm_replay_overflow_bmp,
};
static struct xfrm_replay xfrm_replay_esn = {
.advance = xfrm_replay_advance_esn,
.check = xfrm_replay_check_esn,
.notify = xfrm_replay_notify_bmp,
.overflow = xfrm_replay_overflow_esn,
};
int xfrm_init_replay(struct xfrm_state *x)
{
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
if (replay_esn) {
if (replay_esn->replay_window >
replay_esn->bmp_len * sizeof(__u32) * 8)
return -EINVAL;
if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
return -EINVAL;
if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
x->repl = &xfrm_replay_esn;
else
x->repl = &xfrm_replay_bmp;
} else
x->repl = &xfrm_replay_legacy;
return 0;
}
EXPORT_SYMBOL(xfrm_init_replay);
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