Commit b411b363 authored by Philipp Reisner's avatar Philipp Reisner Committed by Jens Axboe

The DRBD driver

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 1a35e0f6
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Description
DRBD is a shared-nothing, synchronously replicated block device. It
is designed to serve as a building block for high availability
clusters and in this context, is a "drop-in" replacement for shared
storage. Simplistically, you could see it as a network RAID 1.
Please visit http://www.drbd.org to find out more.
The here included files are intended to help understand the implementation
DRBD-8.3-data-packets.svg, DRBD-data-packets.svg
relates some functions, and write packets.
conn-states-8.dot, disk-states-8.dot, node-states-8.dot
The sub graphs of DRBD's state transitions
digraph conn_states {
StandAllone -> WFConnection [ label = "ioctl_set_net()" ]
WFConnection -> Unconnected [ label = "unable to bind()" ]
WFConnection -> WFReportParams [ label = "in connect() after accept" ]
WFReportParams -> StandAllone [ label = "checks in receive_param()" ]
WFReportParams -> Connected [ label = "in receive_param()" ]
WFReportParams -> WFBitMapS [ label = "sync_handshake()" ]
WFReportParams -> WFBitMapT [ label = "sync_handshake()" ]
WFBitMapS -> SyncSource [ label = "receive_bitmap()" ]
WFBitMapT -> SyncTarget [ label = "receive_bitmap()" ]
SyncSource -> Connected
SyncTarget -> Connected
SyncSource -> PausedSyncS
SyncTarget -> PausedSyncT
PausedSyncS -> SyncSource
PausedSyncT -> SyncTarget
Connected -> WFConnection [ label = "* on network error" ]
}
digraph disk_states {
Diskless -> Inconsistent [ label = "ioctl_set_disk()" ]
Diskless -> Consistent [ label = "ioctl_set_disk()" ]
Diskless -> Outdated [ label = "ioctl_set_disk()" ]
Consistent -> Outdated [ label = "receive_param()" ]
Consistent -> UpToDate [ label = "receive_param()" ]
Consistent -> Inconsistent [ label = "start resync" ]
Outdated -> Inconsistent [ label = "start resync" ]
UpToDate -> Inconsistent [ label = "ioctl_replicate" ]
Inconsistent -> UpToDate [ label = "resync completed" ]
Consistent -> Failed [ label = "io completion error" ]
Outdated -> Failed [ label = "io completion error" ]
UpToDate -> Failed [ label = "io completion error" ]
Inconsistent -> Failed [ label = "io completion error" ]
Failed -> Diskless [ label = "sending notify to peer" ]
}
// vim: set sw=2 sts=2 :
digraph {
rankdir=BT
bgcolor=white
node [shape=plaintext]
node [fontcolor=black]
StandAlone [ style=filled,fillcolor=gray,label=StandAlone ]
node [fontcolor=lightgray]
Unconnected [ label=Unconnected ]
CommTrouble [ shape=record,
label="{communication loss|{Timeout|BrokenPipe|NetworkFailure}}" ]
node [fontcolor=gray]
subgraph cluster_try_connect {
label="try to connect, handshake"
rank=max
WFConnection [ label=WFConnection ]
WFReportParams [ label=WFReportParams ]
}
TearDown [ label=TearDown ]
Connected [ label=Connected,style=filled,fillcolor=green,fontcolor=black ]
node [fontcolor=lightblue]
StartingSyncS [ label=StartingSyncS ]
StartingSyncT [ label=StartingSyncT ]
subgraph cluster_bitmap_exchange {
node [fontcolor=red]
fontcolor=red
label="new application (WRITE?) requests blocked\lwhile bitmap is exchanged"
WFBitMapT [ label=WFBitMapT ]
WFSyncUUID [ label=WFSyncUUID ]
WFBitMapS [ label=WFBitMapS ]
}
node [fontcolor=blue]
cluster_resync [ shape=record,label="{<any>resynchronisation process running\l'concurrent' application requests allowed|{{<T>PausedSyncT\nSyncTarget}|{<S>PausedSyncS\nSyncSource}}}" ]
node [shape=box,fontcolor=black]
// drbdadm [label="drbdadm connect"]
// handshake [label="drbd_connect()\ndrbd_do_handshake\ndrbd_sync_handshake() etc."]
// comm_error [label="communication trouble"]
//
// edges
// --------------------------------------
StandAlone -> Unconnected [ label="drbdadm connect" ]
Unconnected -> StandAlone [ label="drbdadm disconnect\lor serious communication trouble" ]
Unconnected -> WFConnection [ label="receiver thread is started" ]
WFConnection -> WFReportParams [ headlabel="accept()\land/or \lconnect()\l" ]
WFReportParams -> StandAlone [ label="during handshake\lpeers do not agree\labout something essential" ]
WFReportParams -> Connected [ label="data identical\lno sync needed",color=green,fontcolor=green ]
WFReportParams -> WFBitMapS
WFReportParams -> WFBitMapT
WFBitMapT -> WFSyncUUID [minlen=0.1,constraint=false]
WFBitMapS -> cluster_resync:S
WFSyncUUID -> cluster_resync:T
edge [color=green]
cluster_resync:any -> Connected [ label="resnyc done",fontcolor=green ]
edge [color=red]
WFReportParams -> CommTrouble
Connected -> CommTrouble
cluster_resync:any -> CommTrouble
edge [color=black]
CommTrouble -> Unconnected [label="receiver thread is stopped" ]
}
digraph node_states {
Secondary -> Primary [ label = "ioctl_set_state()" ]
Primary -> Secondary [ label = "ioctl_set_state()" ]
}
digraph peer_states {
Secondary -> Primary [ label = "recv state packet" ]
Primary -> Secondary [ label = "recv state packet" ]
Primary -> Unknown [ label = "connection lost" ]
Secondary -> Unknown [ label = "connection lost" ]
Unknown -> Primary [ label = "connected" ]
Unknown -> Secondary [ label = "connected" ]
}
......@@ -1758,6 +1758,19 @@ S: Maintained
F: drivers/scsi/dpt*
F: drivers/scsi/dpt/
DRBD DRIVER
P: Philipp Reisner
P: Lars Ellenberg
M: drbd-dev@lists.linbit.com
L: drbd-user@lists.linbit.com
W: http://www.drbd.org
T: git git://git.drbd.org/linux-2.6-drbd.git drbd
T: git git://git.drbd.org/drbd-8.3.git
S: Supported
F: drivers/block/drbd/
F: lib/lru_cache.c
F: Documentation/blockdev/drbd/
DRIVER CORE, KOBJECTS, AND SYSFS
M: Greg Kroah-Hartman <gregkh@suse.de>
T: quilt kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
......
......@@ -271,6 +271,8 @@ config BLK_DEV_CRYPTOLOOP
instead, which can be configured to be on-disk compatible with the
cryptoloop device.
source "drivers/block/drbd/Kconfig"
config BLK_DEV_NBD
tristate "Network block device support"
depends on NET
......
......@@ -36,5 +36,6 @@ obj-$(CONFIG_BLK_DEV_UB) += ub.o
obj-$(CONFIG_BLK_DEV_HD) += hd.o
obj-$(CONFIG_XEN_BLKDEV_FRONTEND) += xen-blkfront.o
obj-$(CONFIG_BLK_DEV_DRBD) += drbd/
swim_mod-objs := swim.o swim_asm.o
#
# DRBD device driver configuration
#
comment "DRBD disabled because PROC_FS, INET or CONNECTOR not selected"
depends on !PROC_FS || !INET || !CONNECTOR
config BLK_DEV_DRBD
tristate "DRBD Distributed Replicated Block Device support"
depends on PROC_FS && INET && CONNECTOR
select LRU_CACHE
default n
help
NOTE: In order to authenticate connections you have to select
CRYPTO_HMAC and a hash function as well.
DRBD is a shared-nothing, synchronously replicated block device. It
is designed to serve as a building block for high availability
clusters and in this context, is a "drop-in" replacement for shared
storage. Simplistically, you could see it as a network RAID 1.
Each minor device has a role, which can be 'primary' or 'secondary'.
On the node with the primary device the application is supposed to
run and to access the device (/dev/drbdX). Every write is sent to
the local 'lower level block device' and, across the network, to the
node with the device in 'secondary' state. The secondary device
simply writes the data to its lower level block device.
DRBD can also be used in dual-Primary mode (device writable on both
nodes), which means it can exhibit shared disk semantics in a
shared-nothing cluster. Needless to say, on top of dual-Primary
DRBD utilizing a cluster file system is necessary to maintain for
cache coherency.
For automatic failover you need a cluster manager (e.g. heartbeat).
See also: http://www.drbd.org/, http://www.linux-ha.org
If unsure, say N.
config DRBD_TRACE
tristate "DRBD tracing"
depends on BLK_DEV_DRBD
select TRACEPOINTS
default n
help
Say Y here if you want to be able to trace various events in DRBD.
If unsure, say N.
config DRBD_FAULT_INJECTION
bool "DRBD fault injection"
depends on BLK_DEV_DRBD
help
Say Y here if you want to simulate IO errors, in order to test DRBD's
behavior.
The actual simulation of IO errors is done by writing 3 values to
/sys/module/drbd/parameters/
enable_faults: bitmask of...
1 meta data write
2 read
4 resync data write
8 read
16 data write
32 data read
64 read ahead
128 kmalloc of bitmap
256 allocation of EE (epoch_entries)
fault_devs: bitmask of minor numbers
fault_rate: frequency in percent
Example: Simulate data write errors on /dev/drbd0 with a probability of 5%.
echo 16 > /sys/module/drbd/parameters/enable_faults
echo 1 > /sys/module/drbd/parameters/fault_devs
echo 5 > /sys/module/drbd/parameters/fault_rate
If unsure, say N.
drbd-y := drbd_bitmap.o drbd_proc.o
drbd-y += drbd_worker.o drbd_receiver.o drbd_req.o drbd_actlog.o
drbd-y += drbd_main.o drbd_strings.o drbd_nl.o
drbd_trace-y := drbd_tracing.o
obj-$(CONFIG_BLK_DEV_DRBD) += drbd.o
obj-$(CONFIG_DRBD_TRACE) += drbd_trace.o
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/*
drbd_proc.c
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
drbd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
drbd is distributed in the hope that 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 drbd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/autoconf.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/drbd.h>
#include "drbd_int.h"
static int drbd_proc_open(struct inode *inode, struct file *file);
struct proc_dir_entry *drbd_proc;
struct file_operations drbd_proc_fops = {
.owner = THIS_MODULE,
.open = drbd_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
/*lge
* progress bars shamelessly adapted from driver/md/md.c
* output looks like
* [=====>..............] 33.5% (23456/123456)
* finish: 2:20:20 speed: 6,345 (6,456) K/sec
*/
static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq)
{
unsigned long db, dt, dbdt, rt, rs_left;
unsigned int res;
int i, x, y;
drbd_get_syncer_progress(mdev, &rs_left, &res);
x = res/50;
y = 20-x;
seq_printf(seq, "\t[");
for (i = 1; i < x; i++)
seq_printf(seq, "=");
seq_printf(seq, ">");
for (i = 0; i < y; i++)
seq_printf(seq, ".");
seq_printf(seq, "] ");
seq_printf(seq, "sync'ed:%3u.%u%% ", res / 10, res % 10);
/* if more than 1 GB display in MB */
if (mdev->rs_total > 0x100000L)
seq_printf(seq, "(%lu/%lu)M\n\t",
(unsigned long) Bit2KB(rs_left >> 10),
(unsigned long) Bit2KB(mdev->rs_total >> 10));
else
seq_printf(seq, "(%lu/%lu)K\n\t",
(unsigned long) Bit2KB(rs_left),
(unsigned long) Bit2KB(mdev->rs_total));
/* see drivers/md/md.c
* We do not want to overflow, so the order of operands and
* the * 100 / 100 trick are important. We do a +1 to be
* safe against division by zero. We only estimate anyway.
*
* dt: time from mark until now
* db: blocks written from mark until now
* rt: remaining time
*/
dt = (jiffies - mdev->rs_mark_time) / HZ;
if (dt > 20) {
/* if we made no update to rs_mark_time for too long,
* we are stalled. show that. */
seq_printf(seq, "stalled\n");
return;
}
if (!dt)
dt++;
db = mdev->rs_mark_left - rs_left;
rt = (dt * (rs_left / (db/100+1)))/100; /* seconds */
seq_printf(seq, "finish: %lu:%02lu:%02lu",
rt / 3600, (rt % 3600) / 60, rt % 60);
/* current speed average over (SYNC_MARKS * SYNC_MARK_STEP) jiffies */
dbdt = Bit2KB(db/dt);
if (dbdt > 1000)
seq_printf(seq, " speed: %ld,%03ld",
dbdt/1000, dbdt % 1000);
else
seq_printf(seq, " speed: %ld", dbdt);
/* mean speed since syncer started
* we do account for PausedSync periods */
dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
if (dt <= 0)
dt = 1;
db = mdev->rs_total - rs_left;
dbdt = Bit2KB(db/dt);
if (dbdt > 1000)
seq_printf(seq, " (%ld,%03ld)",
dbdt/1000, dbdt % 1000);
else
seq_printf(seq, " (%ld)", dbdt);
seq_printf(seq, " K/sec\n");
}
static void resync_dump_detail(struct seq_file *seq, struct lc_element *e)
{
struct bm_extent *bme = lc_entry(e, struct bm_extent, lce);
seq_printf(seq, "%5d %s %s\n", bme->rs_left,
bme->flags & BME_NO_WRITES ? "NO_WRITES" : "---------",
bme->flags & BME_LOCKED ? "LOCKED" : "------"
);
}
static int drbd_seq_show(struct seq_file *seq, void *v)
{
int i, hole = 0;
const char *sn;
struct drbd_conf *mdev;
static char write_ordering_chars[] = {
[WO_none] = 'n',
[WO_drain_io] = 'd',
[WO_bdev_flush] = 'f',
[WO_bio_barrier] = 'b',
};
seq_printf(seq, "version: " REL_VERSION " (api:%d/proto:%d-%d)\n%s\n",
API_VERSION, PRO_VERSION_MIN, PRO_VERSION_MAX, drbd_buildtag());
/*
cs .. connection state
ro .. node role (local/remote)
ds .. disk state (local/remote)
protocol
various flags
ns .. network send
nr .. network receive
dw .. disk write
dr .. disk read
al .. activity log write count
bm .. bitmap update write count
pe .. pending (waiting for ack or data reply)
ua .. unack'd (still need to send ack or data reply)
ap .. application requests accepted, but not yet completed
ep .. number of epochs currently "on the fly", P_BARRIER_ACK pending
wo .. write ordering mode currently in use
oos .. known out-of-sync kB
*/
for (i = 0; i < minor_count; i++) {
mdev = minor_to_mdev(i);
if (!mdev) {
hole = 1;
continue;
}
if (hole) {
hole = 0;
seq_printf(seq, "\n");
}
sn = drbd_conn_str(mdev->state.conn);
if (mdev->state.conn == C_STANDALONE &&
mdev->state.disk == D_DISKLESS &&
mdev->state.role == R_SECONDARY) {
seq_printf(seq, "%2d: cs:Unconfigured\n", i);
} else {
seq_printf(seq,
"%2d: cs:%s ro:%s/%s ds:%s/%s %c %c%c%c%c%c\n"
" ns:%u nr:%u dw:%u dr:%u al:%u bm:%u "
"lo:%d pe:%d ua:%d ap:%d ep:%d wo:%c",
i, sn,
drbd_role_str(mdev->state.role),
drbd_role_str(mdev->state.peer),
drbd_disk_str(mdev->state.disk),
drbd_disk_str(mdev->state.pdsk),
(mdev->net_conf == NULL ? ' ' :
(mdev->net_conf->wire_protocol - DRBD_PROT_A+'A')),
mdev->state.susp ? 's' : 'r',
mdev->state.aftr_isp ? 'a' : '-',
mdev->state.peer_isp ? 'p' : '-',
mdev->state.user_isp ? 'u' : '-',
mdev->congestion_reason ?: '-',
mdev->send_cnt/2,
mdev->recv_cnt/2,
mdev->writ_cnt/2,
mdev->read_cnt/2,
mdev->al_writ_cnt,
mdev->bm_writ_cnt,
atomic_read(&mdev->local_cnt),
atomic_read(&mdev->ap_pending_cnt) +
atomic_read(&mdev->rs_pending_cnt),
atomic_read(&mdev->unacked_cnt),
atomic_read(&mdev->ap_bio_cnt),
mdev->epochs,
write_ordering_chars[mdev->write_ordering]
);
seq_printf(seq, " oos:%lu\n",
Bit2KB(drbd_bm_total_weight(mdev)));
}
if (mdev->state.conn == C_SYNC_SOURCE ||
mdev->state.conn == C_SYNC_TARGET)
drbd_syncer_progress(mdev, seq);
if (mdev->state.conn == C_VERIFY_S || mdev->state.conn == C_VERIFY_T)
seq_printf(seq, "\t%3d%% %lu/%lu\n",
(int)((mdev->rs_total-mdev->ov_left) /
(mdev->rs_total/100+1)),
mdev->rs_total - mdev->ov_left,
mdev->rs_total);
if (proc_details >= 1 && get_ldev_if_state(mdev, D_FAILED)) {
lc_seq_printf_stats(seq, mdev->resync);
lc_seq_printf_stats(seq, mdev->act_log);
put_ldev(mdev);
}
if (proc_details >= 2) {
if (mdev->resync) {
lc_seq_dump_details(seq, mdev->resync, "rs_left",
resync_dump_detail);
}
}
}
return 0;
}
static int drbd_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, drbd_seq_show, PDE(inode)->data);
}
/* PROC FS stuff end */
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/*
drbd.h
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
drbd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
drbd is distributed in the hope that 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 drbd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/drbd.h>
static const char *drbd_conn_s_names[] = {
[C_STANDALONE] = "StandAlone",
[C_DISCONNECTING] = "Disconnecting",
[C_UNCONNECTED] = "Unconnected",
[C_TIMEOUT] = "Timeout",
[C_BROKEN_PIPE] = "BrokenPipe",
[C_NETWORK_FAILURE] = "NetworkFailure",
[C_PROTOCOL_ERROR] = "ProtocolError",
[C_WF_CONNECTION] = "WFConnection",
[C_WF_REPORT_PARAMS] = "WFReportParams",
[C_TEAR_DOWN] = "TearDown",
[C_CONNECTED] = "Connected",
[C_STARTING_SYNC_S] = "StartingSyncS",
[C_STARTING_SYNC_T] = "StartingSyncT",
[C_WF_BITMAP_S] = "WFBitMapS",
[C_WF_BITMAP_T] = "WFBitMapT",
[C_WF_SYNC_UUID] = "WFSyncUUID",
[C_SYNC_SOURCE] = "SyncSource",
[C_SYNC_TARGET] = "SyncTarget",
[C_PAUSED_SYNC_S] = "PausedSyncS",
[C_PAUSED_SYNC_T] = "PausedSyncT",
[C_VERIFY_S] = "VerifyS",
[C_VERIFY_T] = "VerifyT",
};
static const char *drbd_role_s_names[] = {
[R_PRIMARY] = "Primary",
[R_SECONDARY] = "Secondary",
[R_UNKNOWN] = "Unknown"
};
static const char *drbd_disk_s_names[] = {
[D_DISKLESS] = "Diskless",
[D_ATTACHING] = "Attaching",
[D_FAILED] = "Failed",
[D_NEGOTIATING] = "Negotiating",
[D_INCONSISTENT] = "Inconsistent",
[D_OUTDATED] = "Outdated",
[D_UNKNOWN] = "DUnknown",
[D_CONSISTENT] = "Consistent",
[D_UP_TO_DATE] = "UpToDate",
};
static const char *drbd_state_sw_errors[] = {
[-SS_TWO_PRIMARIES] = "Multiple primaries not allowed by config",
[-SS_NO_UP_TO_DATE_DISK] = "Refusing to be Primary without at least one UpToDate disk",
[-SS_NO_LOCAL_DISK] = "Can not resync without local disk",
[-SS_NO_REMOTE_DISK] = "Can not resync without remote disk",
[-SS_CONNECTED_OUTDATES] = "Refusing to be Outdated while Connected",
[-SS_PRIMARY_NOP] = "Refusing to be Primary while peer is not outdated",
[-SS_RESYNC_RUNNING] = "Can not start OV/resync since it is already active",
[-SS_ALREADY_STANDALONE] = "Can not disconnect a StandAlone device",
[-SS_CW_FAILED_BY_PEER] = "State change was refused by peer node",
[-SS_IS_DISKLESS] = "Device is diskless, the requested operation requires a disk",
[-SS_DEVICE_IN_USE] = "Device is held open by someone",
[-SS_NO_NET_CONFIG] = "Have no net/connection configuration",
[-SS_NO_VERIFY_ALG] = "Need a verify algorithm to start online verify",
[-SS_NEED_CONNECTION] = "Need a connection to start verify or resync",
[-SS_NOT_SUPPORTED] = "Peer does not support protocol",
[-SS_LOWER_THAN_OUTDATED] = "Disk state is lower than outdated",
[-SS_IN_TRANSIENT_STATE] = "In transient state, retry after next state change",
[-SS_CONCURRENT_ST_CHG] = "Concurrent state changes detected and aborted",
};
const char *drbd_conn_str(enum drbd_conns s)
{
/* enums are unsigned... */
return s > C_PAUSED_SYNC_T ? "TOO_LARGE" : drbd_conn_s_names[s];
}
const char *drbd_role_str(enum drbd_role s)
{
return s > R_SECONDARY ? "TOO_LARGE" : drbd_role_s_names[s];
}
const char *drbd_disk_str(enum drbd_disk_state s)
{
return s > D_UP_TO_DATE ? "TOO_LARGE" : drbd_disk_s_names[s];
}
const char *drbd_set_st_err_str(enum drbd_state_ret_codes err)
{
return err <= SS_AFTER_LAST_ERROR ? "TOO_SMALL" :
err > SS_TWO_PRIMARIES ? "TOO_LARGE"
: drbd_state_sw_errors[-err];
}
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/*
drbd_tracing.h
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
drbd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
drbd is distributed in the hope that 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 drbd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef DRBD_TRACING_H
#define DRBD_TRACING_H
#include <linux/tracepoint.h>
#include "drbd_int.h"
#include "drbd_req.h"
enum {
TRACE_LVL_ALWAYS =