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lvm2/device_mapper/ioctl/libdm-targets.h
David Teigland d9e8895a96 Allow dm-integrity to be used for raid images
dm-integrity stores checksums of the data written to an
LV, and returns an error if data read from the LV does
not match the previously saved checksum.  When used on
raid images, dm-raid will correct the error by reading
the block from another image, and the device user sees
no error.  The integrity metadata (checksums) are stored
on an internal LV allocated by lvm for each linear image.
The internal LV is allocated on the same PV as the image.

Create a raid LV with an integrity layer over each
raid image (for raid levels 1,4,5,6,10):

lvcreate --type raidN --raidintegrity y [options]

Add an integrity layer to images of an existing raid LV:

lvconvert --raidintegrity y LV

Remove the integrity layer from images of a raid LV:

lvconvert --raidintegrity n LV

Settings

Use --raidintegritymode journal|bitmap (journal is default)
to configure the method used by dm-integrity to ensure
crash consistency.

Initialization

When integrity is added to an LV, the kernel needs to
initialize the integrity metadata/checksums for all blocks
in the LV.  The data corruption checking performed by
dm-integrity will only operate on areas of the LV that
are already initialized.  The progress of integrity
initialization is reported by the "syncpercent" LV
reporting field (and under the Cpy%Sync lvs column.)

Example: create a raid1 LV with integrity:

$ lvcreate --type raid1 -m1 --raidintegrity y -n rr -L1G foo
  Creating integrity metadata LV rr_rimage_0_imeta with size 12.00 MiB.
  Logical volume "rr_rimage_0_imeta" created.
  Creating integrity metadata LV rr_rimage_1_imeta with size 12.00 MiB.
  Logical volume "rr_rimage_1_imeta" created.
  Logical volume "rr" created.
$ lvs -a foo
  LV                  VG  Attr       LSize  Origin              Cpy%Sync
  rr                  foo rwi-a-r---  1.00g                     4.93
  [rr_rimage_0]       foo gwi-aor---  1.00g [rr_rimage_0_iorig] 41.02
  [rr_rimage_0_imeta] foo ewi-ao---- 12.00m
  [rr_rimage_0_iorig] foo -wi-ao----  1.00g
  [rr_rimage_1]       foo gwi-aor---  1.00g [rr_rimage_1_iorig] 39.45
  [rr_rimage_1_imeta] foo ewi-ao---- 12.00m
  [rr_rimage_1_iorig] foo -wi-ao----  1.00g
  [rr_rmeta_0]        foo ewi-aor---  4.00m
  [rr_rmeta_1]        foo ewi-aor---  4.00m
2020-04-15 12:10:32 -05:00

90 lines
1.8 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef LIB_DMTARGETS_H
#define LIB_DMTARGETS_H
#include <inttypes.h>
#include <sys/types.h>
struct dm_ioctl;
struct target {
uint64_t start;
uint64_t length;
char *type;
char *params;
struct target *next;
};
struct dm_task {
int type;
char *dev_name;
char *mangled_dev_name;
struct target *head, *tail;
int read_only;
uint32_t event_nr;
int major;
int minor;
int allow_default_major_fallback;
uid_t uid;
gid_t gid;
mode_t mode;
uint32_t read_ahead;
uint32_t read_ahead_flags;
union {
struct dm_ioctl *v4;
} dmi;
char *newname;
char *message;
char *geometry;
uint64_t sector;
int no_flush;
int no_open_count;
int skip_lockfs;
int query_inactive_table;
int suppress_identical_reload;
int skip_reload_params_compare;
dm_add_node_t add_node;
uint64_t existing_table_size;
int cookie_set;
int new_uuid;
int secure_data;
int retry_remove;
int deferred_remove;
int enable_checks;
int expected_errno;
int ioctl_errno;
int record_timestamp;
char *uuid;
char *mangled_uuid;
};
struct cmd_data {
const char *name;
const unsigned cmd;
const int version[3];
};
int dm_check_version(void);
uint64_t dm_task_get_existing_table_size(struct dm_task *dmt);
#endif