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linux-next/include/linux/drbd.h
Lars Ellenberg f31e583aa2 drbd: introduce P_ZEROES (REQ_OP_WRITE_ZEROES on the "wire") 
And also re-enable partial-zero-out + discard aligned.

With the introduction of REQ_OP_WRITE_ZEROES,
we started to use that for both WRITE_ZEROES and DISCARDS,
hoping that WRITE_ZEROES would "do what we want",
UNMAP if possible, zero-out the rest.

The example scenario is some LVM "thin" backend.

While an un-allocated block on dm-thin reads as zeroes, on a dm-thin
with "skip_block_zeroing=true", after a partial block write allocated
that block, that same block may well map "undefined old garbage" from
the backends on LBAs that have not yet been written to.

If we cannot distinguish between zero-out and discard on the receiving
side, to avoid "undefined old garbage" to pop up randomly at later times
on supposedly zero-initialized blocks, we'd need to map all discards to
zero-out on the receiving side.  But that would potentially do a full
alloc on thinly provisioned backends, even when the expectation was to
unmap/trim/discard/de-allocate.

We need to distinguish on the protocol level, whether we need to guarantee
zeroes (and thus use zero-out, potentially doing the mentioned full-alloc),
or if we want to put the emphasis on discard, and only do a "best effort
zeroing" (by "discarding" blocks aligned to discard-granularity, and zeroing
only potential unaligned head and tail clippings to at least *try* to
avoid "false positives" in an online-verify later), hoping that someone
set skip_block_zeroing=false.

For some discussion regarding this on dm-devel, see also
https://www.mail-archive.com/dm-devel%40redhat.com/msg07965.html
https://www.redhat.com/archives/dm-devel/2018-January/msg00271.html

For backward compatibility, P_TRIM means zero-out, unless the
DRBD_FF_WZEROES feature flag is agreed upon during handshake.

To have upper layers even try to submit WRITE ZEROES requests,
we need to announce "efficient zeroout" independently.

We need to fixup max_write_zeroes_sectors after blk_queue_stack_limits():
if we can handle "zeroes" efficiently on the protocol,
we want to do that, even if our backend does not announce
max_write_zeroes_sectors itself.

Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-20 09:51:31 -07:00

412 lines
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/*
drbd.h
Kernel module for 2.6.x Kernels
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
Copyright (C) 2001-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2001-2008, 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_H
#define DRBD_H
#include <asm/types.h>
#ifdef __KERNEL__
#include <linux/types.h>
#include <asm/byteorder.h>
#else
#include <sys/types.h>
#include <sys/wait.h>
#include <limits.h>
/* Although the Linux source code makes a difference between
generic endianness and the bitfields' endianness, there is no
architecture as of Linux-2.6.24-rc4 where the bitfields' endianness
does not match the generic endianness. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define __LITTLE_ENDIAN_BITFIELD
#elif __BYTE_ORDER == __BIG_ENDIAN
#define __BIG_ENDIAN_BITFIELD
#else
# error "sorry, weird endianness on this box"
#endif
#endif
extern const char *drbd_buildtag(void);
#define REL_VERSION "8.4.11"
#define API_VERSION 1
#define PRO_VERSION_MIN 86
#define PRO_VERSION_MAX 101
enum drbd_io_error_p {
EP_PASS_ON, /* FIXME should the better be named "Ignore"? */
EP_CALL_HELPER,
EP_DETACH
};
enum drbd_fencing_p {
FP_NOT_AVAIL = -1, /* Not a policy */
FP_DONT_CARE = 0,
FP_RESOURCE,
FP_STONITH
};
enum drbd_disconnect_p {
DP_RECONNECT,
DP_DROP_NET_CONF,
DP_FREEZE_IO
};
enum drbd_after_sb_p {
ASB_DISCONNECT,
ASB_DISCARD_YOUNGER_PRI,
ASB_DISCARD_OLDER_PRI,
ASB_DISCARD_ZERO_CHG,
ASB_DISCARD_LEAST_CHG,
ASB_DISCARD_LOCAL,
ASB_DISCARD_REMOTE,
ASB_CONSENSUS,
ASB_DISCARD_SECONDARY,
ASB_CALL_HELPER,
ASB_VIOLENTLY
};
enum drbd_on_no_data {
OND_IO_ERROR,
OND_SUSPEND_IO
};
enum drbd_on_congestion {
OC_BLOCK,
OC_PULL_AHEAD,
OC_DISCONNECT,
};
enum drbd_read_balancing {
RB_PREFER_LOCAL,
RB_PREFER_REMOTE,
RB_ROUND_ROBIN,
RB_LEAST_PENDING,
RB_CONGESTED_REMOTE,
RB_32K_STRIPING,
RB_64K_STRIPING,
RB_128K_STRIPING,
RB_256K_STRIPING,
RB_512K_STRIPING,
RB_1M_STRIPING,
};
/* KEEP the order, do not delete or insert. Only append. */
enum drbd_ret_code {
ERR_CODE_BASE = 100,
NO_ERROR = 101,
ERR_LOCAL_ADDR = 102,
ERR_PEER_ADDR = 103,
ERR_OPEN_DISK = 104,
ERR_OPEN_MD_DISK = 105,
ERR_DISK_NOT_BDEV = 107,
ERR_MD_NOT_BDEV = 108,
ERR_DISK_TOO_SMALL = 111,
ERR_MD_DISK_TOO_SMALL = 112,
ERR_BDCLAIM_DISK = 114,
ERR_BDCLAIM_MD_DISK = 115,
ERR_MD_IDX_INVALID = 116,
ERR_IO_MD_DISK = 118,
ERR_MD_INVALID = 119,
ERR_AUTH_ALG = 120,
ERR_AUTH_ALG_ND = 121,
ERR_NOMEM = 122,
ERR_DISCARD_IMPOSSIBLE = 123,
ERR_DISK_CONFIGURED = 124,
ERR_NET_CONFIGURED = 125,
ERR_MANDATORY_TAG = 126,
ERR_MINOR_INVALID = 127,
ERR_INTR = 129, /* EINTR */
ERR_RESIZE_RESYNC = 130,
ERR_NO_PRIMARY = 131,
ERR_RESYNC_AFTER = 132,
ERR_RESYNC_AFTER_CYCLE = 133,
ERR_PAUSE_IS_SET = 134,
ERR_PAUSE_IS_CLEAR = 135,
ERR_PACKET_NR = 137,
ERR_NO_DISK = 138,
ERR_NOT_PROTO_C = 139,
ERR_NOMEM_BITMAP = 140,
ERR_INTEGRITY_ALG = 141, /* DRBD 8.2 only */
ERR_INTEGRITY_ALG_ND = 142, /* DRBD 8.2 only */
ERR_CPU_MASK_PARSE = 143, /* DRBD 8.2 only */
ERR_CSUMS_ALG = 144, /* DRBD 8.2 only */
ERR_CSUMS_ALG_ND = 145, /* DRBD 8.2 only */
ERR_VERIFY_ALG = 146, /* DRBD 8.2 only */
ERR_VERIFY_ALG_ND = 147, /* DRBD 8.2 only */
ERR_CSUMS_RESYNC_RUNNING= 148, /* DRBD 8.2 only */
ERR_VERIFY_RUNNING = 149, /* DRBD 8.2 only */
ERR_DATA_NOT_CURRENT = 150,
ERR_CONNECTED = 151, /* DRBD 8.3 only */
ERR_PERM = 152,
ERR_NEED_APV_93 = 153,
ERR_STONITH_AND_PROT_A = 154,
ERR_CONG_NOT_PROTO_A = 155,
ERR_PIC_AFTER_DEP = 156,
ERR_PIC_PEER_DEP = 157,
ERR_RES_NOT_KNOWN = 158,
ERR_RES_IN_USE = 159,
ERR_MINOR_CONFIGURED = 160,
ERR_MINOR_OR_VOLUME_EXISTS = 161,
ERR_INVALID_REQUEST = 162,
ERR_NEED_APV_100 = 163,
ERR_NEED_ALLOW_TWO_PRI = 164,
ERR_MD_UNCLEAN = 165,
ERR_MD_LAYOUT_CONNECTED = 166,
ERR_MD_LAYOUT_TOO_BIG = 167,
ERR_MD_LAYOUT_TOO_SMALL = 168,
ERR_MD_LAYOUT_NO_FIT = 169,
ERR_IMPLICIT_SHRINK = 170,
/* insert new ones above this line */
AFTER_LAST_ERR_CODE
};
#define DRBD_PROT_A 1
#define DRBD_PROT_B 2
#define DRBD_PROT_C 3
enum drbd_role {
R_UNKNOWN = 0,
R_PRIMARY = 1, /* role */
R_SECONDARY = 2, /* role */
R_MASK = 3,
};
/* The order of these constants is important.
* The lower ones (<C_WF_REPORT_PARAMS) indicate
* that there is no socket!
* >=C_WF_REPORT_PARAMS ==> There is a socket
*/
enum drbd_conns {
C_STANDALONE,
C_DISCONNECTING, /* Temporal state on the way to StandAlone. */
C_UNCONNECTED, /* >= C_UNCONNECTED -> inc_net() succeeds */
/* These temporal states are all used on the way
* from >= C_CONNECTED to Unconnected.
* The 'disconnect reason' states
* I do not allow to change between them. */
C_TIMEOUT,
C_BROKEN_PIPE,
C_NETWORK_FAILURE,
C_PROTOCOL_ERROR,
C_TEAR_DOWN,
C_WF_CONNECTION,
C_WF_REPORT_PARAMS, /* we have a socket */
C_CONNECTED, /* we have introduced each other */
C_STARTING_SYNC_S, /* starting full sync by admin request. */
C_STARTING_SYNC_T, /* starting full sync by admin request. */
C_WF_BITMAP_S,
C_WF_BITMAP_T,
C_WF_SYNC_UUID,
/* All SyncStates are tested with this comparison
* xx >= C_SYNC_SOURCE && xx <= C_PAUSED_SYNC_T */
C_SYNC_SOURCE,
C_SYNC_TARGET,
C_VERIFY_S,
C_VERIFY_T,
C_PAUSED_SYNC_S,
C_PAUSED_SYNC_T,
C_AHEAD,
C_BEHIND,
C_MASK = 31
};
enum drbd_disk_state {
D_DISKLESS,
D_ATTACHING, /* In the process of reading the meta-data */
D_FAILED, /* Becomes D_DISKLESS as soon as we told it the peer */
/* when >= D_FAILED it is legal to access mdev->ldev */
D_NEGOTIATING, /* Late attaching state, we need to talk to the peer */
D_INCONSISTENT,
D_OUTDATED,
D_UNKNOWN, /* Only used for the peer, never for myself */
D_CONSISTENT, /* Might be D_OUTDATED, might be D_UP_TO_DATE ... */
D_UP_TO_DATE, /* Only this disk state allows applications' IO ! */
D_MASK = 15
};
union drbd_state {
/* According to gcc's docs is the ...
* The order of allocation of bit-fields within a unit (C90 6.5.2.1, C99 6.7.2.1).
* Determined by ABI.
* pointed out by Maxim Uvarov q<muvarov@ru.mvista.com>
* even though we transmit as "cpu_to_be32(state)",
* the offsets of the bitfields still need to be swapped
* on different endianness.
*/
struct {
#if defined(__LITTLE_ENDIAN_BITFIELD)
unsigned role:2 ; /* 3/4 primary/secondary/unknown */
unsigned peer:2 ; /* 3/4 primary/secondary/unknown */
unsigned conn:5 ; /* 17/32 cstates */
unsigned disk:4 ; /* 8/16 from D_DISKLESS to D_UP_TO_DATE */
unsigned pdsk:4 ; /* 8/16 from D_DISKLESS to D_UP_TO_DATE */
unsigned susp:1 ; /* 2/2 IO suspended no/yes (by user) */
unsigned aftr_isp:1 ; /* isp .. imposed sync pause */
unsigned peer_isp:1 ;
unsigned user_isp:1 ;
unsigned susp_nod:1 ; /* IO suspended because no data */
unsigned susp_fen:1 ; /* IO suspended because fence peer handler runs*/
unsigned _pad:9; /* 0 unused */
#elif defined(__BIG_ENDIAN_BITFIELD)
unsigned _pad:9;
unsigned susp_fen:1 ;
unsigned susp_nod:1 ;
unsigned user_isp:1 ;
unsigned peer_isp:1 ;
unsigned aftr_isp:1 ; /* isp .. imposed sync pause */
unsigned susp:1 ; /* 2/2 IO suspended no/yes */
unsigned pdsk:4 ; /* 8/16 from D_DISKLESS to D_UP_TO_DATE */
unsigned disk:4 ; /* 8/16 from D_DISKLESS to D_UP_TO_DATE */
unsigned conn:5 ; /* 17/32 cstates */
unsigned peer:2 ; /* 3/4 primary/secondary/unknown */
unsigned role:2 ; /* 3/4 primary/secondary/unknown */
#else
# error "this endianness is not supported"
#endif
};
unsigned int i;
};
enum drbd_state_rv {
SS_CW_NO_NEED = 4,
SS_CW_SUCCESS = 3,
SS_NOTHING_TO_DO = 2,
SS_SUCCESS = 1,
SS_UNKNOWN_ERROR = 0, /* Used to sleep longer in _drbd_request_state */
SS_TWO_PRIMARIES = -1,
SS_NO_UP_TO_DATE_DISK = -2,
SS_NO_LOCAL_DISK = -4,
SS_NO_REMOTE_DISK = -5,
SS_CONNECTED_OUTDATES = -6,
SS_PRIMARY_NOP = -7,
SS_RESYNC_RUNNING = -8,
SS_ALREADY_STANDALONE = -9,
SS_CW_FAILED_BY_PEER = -10,
SS_IS_DISKLESS = -11,
SS_DEVICE_IN_USE = -12,
SS_NO_NET_CONFIG = -13,
SS_NO_VERIFY_ALG = -14, /* drbd-8.2 only */
SS_NEED_CONNECTION = -15, /* drbd-8.2 only */
SS_LOWER_THAN_OUTDATED = -16,
SS_NOT_SUPPORTED = -17, /* drbd-8.2 only */
SS_IN_TRANSIENT_STATE = -18, /* Retry after the next state change */
SS_CONCURRENT_ST_CHG = -19, /* Concurrent cluster side state change! */
SS_O_VOL_PEER_PRI = -20,
SS_OUTDATE_WO_CONN = -21,
SS_AFTER_LAST_ERROR = -22, /* Keep this at bottom */
};
#define SHARED_SECRET_MAX 64
#define MDF_CONSISTENT (1 << 0)
#define MDF_PRIMARY_IND (1 << 1)
#define MDF_CONNECTED_IND (1 << 2)
#define MDF_FULL_SYNC (1 << 3)
#define MDF_WAS_UP_TO_DATE (1 << 4)
#define MDF_PEER_OUT_DATED (1 << 5)
#define MDF_CRASHED_PRIMARY (1 << 6)
#define MDF_AL_CLEAN (1 << 7)
#define MDF_AL_DISABLED (1 << 8)
#define MAX_PEERS 32
enum drbd_uuid_index {
UI_CURRENT,
UI_BITMAP,
UI_HISTORY_START,
UI_HISTORY_END,
UI_SIZE, /* nl-packet: number of dirty bits */
UI_FLAGS, /* nl-packet: flags */
UI_EXTENDED_SIZE /* Everything. */
};
#define HISTORY_UUIDS MAX_PEERS
enum drbd_timeout_flag {
UT_DEFAULT = 0,
UT_DEGRADED = 1,
UT_PEER_OUTDATED = 2,
};
enum drbd_notification_type {
NOTIFY_EXISTS,
NOTIFY_CREATE,
NOTIFY_CHANGE,
NOTIFY_DESTROY,
NOTIFY_CALL,
NOTIFY_RESPONSE,
NOTIFY_CONTINUES = 0x8000,
NOTIFY_FLAGS = NOTIFY_CONTINUES,
};
enum drbd_peer_state {
P_INCONSISTENT = 3,
P_OUTDATED = 4,
P_DOWN = 5,
P_PRIMARY = 6,
P_FENCING = 7,
};
#define UUID_JUST_CREATED ((__u64)4)
enum write_ordering_e {
WO_NONE,
WO_DRAIN_IO,
WO_BDEV_FLUSH,
WO_BIO_BARRIER
};
/* magic numbers used in meta data and network packets */
#define DRBD_MAGIC 0x83740267
#define DRBD_MAGIC_BIG 0x835a
#define DRBD_MAGIC_100 0x8620ec20
#define DRBD_MD_MAGIC_07 (DRBD_MAGIC+3)
#define DRBD_MD_MAGIC_08 (DRBD_MAGIC+4)
#define DRBD_MD_MAGIC_84_UNCLEAN (DRBD_MAGIC+5)
/* how I came up with this magic?
* base64 decode "actlog==" ;) */
#define DRBD_AL_MAGIC 0x69cb65a2
/* these are of type "int" */
#define DRBD_MD_INDEX_INTERNAL -1
#define DRBD_MD_INDEX_FLEX_EXT -2
#define DRBD_MD_INDEX_FLEX_INT -3
#define DRBD_CPU_MASK_SIZE 32
#endif
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