Files
xen/tools/blktap2/drivers/td.c
T
Keir Fraser bd5573a630 blktap2: a completely rewritten blktap implementation
Benefits to blktap2 over the old version of blktap:

* Isolation from xenstore - Blktap devices are now created directly on
   the linux dom0 command line, rather than being spawned in response
   to XenStore events.  This is handy for debugging, makes blktap
   generally easier to work with, and is a step toward a generic
   user-level block device implementation that is not Xen-specific.

* Improved tapdisk infrastructure: simpler request forwarding, new
   request scheduler, request merging, more efficient use of AIO.

* Improved tapdisk error handling and memory management.  No
   allocations on the block data path, IO retry logic to protect
   guests
   transient block device failures.  This has been tested and is known
   to work on weird environments such as NFS soft mounts.

* Pause and snapshot of live virtual disks (see xmsnap script).

* VHD support.  The VHD code in this release has been rigorously
   tested, and represents a very mature implementation of the VHD
   image
   format.

* No more duplication of mechanism with blkback.  The blktap kernel
   module has changed dramatically from the original blktap.  Blkback
   is now always used to talk to Xen guests, blktap just presents a
   Linux gendisk that blkback can export.  This is done while
   preserving the zero-copy data path from domU to physical device.

These patches deprecate the old blktap code, which can hopefully be
removed from the tree completely at some point in the future.

Signed-off-by: Jake Wires <jake.wires@citrix.com>
Signed-off-by: Dutch Meyer <dmeyer@cs.ubc.ca>
2009-05-26 11:52:31 +01:00

692 lines
14 KiB
C

/*
* Copyright (c) 2008, XenSource Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of XenSource Inc. nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/resource.h>
#include <unistd.h>
#include <string.h>
#include "libvhd.h"
#include "vhd-util.h"
#include "tapdisk-utils.h"
#if 1
#define DFPRINTF(_f, _a...) fprintf ( stdout, _f , ## _a )
#else
#define DFPRINTF(_f, _a...) ((void)0)
#endif
typedef enum {
TD_FIELD_HIDDEN = 0,
TD_FIELD_INVALID = 1
} td_field_t;
struct vdi_field {
char *name;
td_field_t id;
};
static struct vdi_field td_vdi_fields[TD_FIELD_INVALID] = {
{ .id = TD_FIELD_HIDDEN, .name = "hidden" }
};
typedef enum {
TD_CMD_CREATE = 0,
TD_CMD_SNAPSHOT,
/* TD_CMD_COALESCE, */
TD_CMD_QUERY,
/* TD_CMD_RESIZE, */
TD_CMD_SET,
/* TD_CMD_REPAIR, */
/* TD_CMD_FILL, */
/* TD_CMD_READ, */
TD_CMD_INVALID,
} td_command_t;
struct command {
td_command_t id;
char *name;
int needs_type;
};
struct command commands[TD_CMD_INVALID] = {
{ .id = TD_CMD_CREATE, .name = "create", .needs_type = 1 },
{ .id = TD_CMD_SNAPSHOT, .name = "snapshot", .needs_type = 1 },
/* { .id = TD_CMD_COALESCE, .name = "coalesce", .needs_type = 1 }, */
{ .id = TD_CMD_QUERY, .name = "query", .needs_type = 1 },
/* { .id = TD_CMD_RESIZE, .name = "resize", .needs_type = 1 }, */
{ .id = TD_CMD_SET, .name = "set", .needs_type = 1 },
/* { .id = TD_CMD_REPAIR, .name = "repair", .needs_type = 1 }, */
/* { .id = TD_CMD_FILL, .name = "fill", .needs_type = 1 }, */
/* { .id = TD_CMD_READ, .name = "read", .needs_type = 1 }, */
};
typedef enum {
TD_TYPE_VHD = 0,
TD_TYPE_AIO,
TD_TYPE_INVALID,
} td_disk_t;
const char *td_disk_types[TD_TYPE_INVALID] = {
"vhd",
"aio",
};
#define print_commands() \
do { \
int i; \
fprintf(stderr, "COMMAND := { "); \
fprintf(stderr, "%s", commands[0].name); \
for (i = 1; i < TD_CMD_INVALID; i++) \
fprintf(stderr, " | %s", commands[i].name); \
fprintf(stderr, " }\n"); \
} while (0)
#define print_disk_types() \
do { \
int i; \
fprintf(stderr, "TYPE := { "); \
fprintf(stderr, "%s", td_disk_types[0]); \
for (i = 1; i < TD_TYPE_INVALID; i++) \
fprintf(stderr, " | %s", td_disk_types[i]); \
fprintf(stderr, " }\n"); \
} while (0);
#define print_field_names() \
do { \
int i; \
fprintf(stderr, "FIELD := { "); \
fprintf(stderr, "%s", td_vdi_fields[0].name); \
for (i = 1; i < TD_FIELD_INVALID; i++) \
fprintf(stderr, " | %s", td_vdi_fields[i].name); \
fprintf(stderr, " }\n"); \
} while (0)
void
help(void)
{
fprintf(stderr, "Tapdisk Utilities: v1.0.0\n");
fprintf(stderr, "usage: td-util COMMAND [TYPE] [OPTIONS]\n");
print_commands();
print_disk_types();
exit(-1);
}
struct command *
get_command(char *command)
{
int i;
for (i = 0; i < TD_CMD_INVALID; i++)
if (!strcmp(command, commands[i].name))
return &commands[i];
return NULL;
}
struct vdi_field *
get_field(char *field)
{
int i;
for (i = 0; i < TD_FIELD_INVALID; i++)
if (!strcmp(field, td_vdi_fields[i].name))
return &td_vdi_fields[i];
return NULL;
}
int
get_driver_type(char *type)
{
int i;
if (strnlen(type, 25) >= 25)
return -ENAMETOOLONG;
for (i = 0; i < TD_TYPE_INVALID; i++)
if (!strcmp(type, td_disk_types[i]))
return i;
return -TD_TYPE_INVALID;
}
int
td_create(int type, int argc, char *argv[])
{
ssize_t mb;
uint64_t size;
char *name, *buf;
int c, i, fd, sparse = 1, fixedsize = 0;
while ((c = getopt(argc, argv, "hrb")) != -1) {
switch(c) {
case 'r':
sparse = 0;
break;
case 'b':
fixedsize = 1;
break;
default:
fprintf(stderr, "Unknown option %c\n", (char)c);
case 'h':
goto usage;
}
}
if (optind != (argc - 2))
goto usage;
mb = 1 << 20;
size = atoi(argv[optind++]);
size = size << 20;
name = argv[optind];
if (strnlen(name, MAX_NAME_LEN) == MAX_NAME_LEN) {
fprintf(stderr, "Device name too long\n");
return ENAMETOOLONG;
}
if (type == TD_TYPE_VHD) {
int cargc = 0;
char sbuf[32], *cargv[10];
size >>= 20;
memset(cargv, 0, sizeof(cargv));
snprintf(sbuf, sizeof(sbuf) - 1, "%"PRIu64, size);
cargv[cargc++] = "create";
cargv[cargc++] = "-n";
cargv[cargc++] = name;
cargv[cargc++] = "-s";
cargv[cargc++] = sbuf;
if (!sparse)
cargv[cargc++] = "-r";
if (fixedsize)
cargv[cargc++] = "-b";
return vhd_util_create(cargc, cargv);
}
/* generic create */
if (sparse) {
fprintf(stderr, "Cannot create sparse %s image\n",
td_disk_types[type]);
return EINVAL;
}
buf = calloc(1, mb);
if (!buf)
return ENOMEM;
fd = open(name, O_WRONLY | O_DIRECT | O_CREAT | O_TRUNC, 0644);
if (fd == -1) {
free(buf);
return errno;
}
size >>= 20;
for (i = 0; i < size; i++)
if (write(fd, buf, mb) != mb) {
close(fd);
unlink(name);
free(buf);
return EIO;
}
close(fd);
free(buf);
return 0;
usage:
fprintf(stderr, "usage: td-util create %s [-h help] [-r reserve] "
"[-b file_is_fixed_size] <SIZE(MB)> <FILENAME>\n",
td_disk_types[type]);
return EINVAL;
}
int
td_snapshot(int type, int argc, char *argv[])
{
char *cargv[10];
int c, err, cargc;
struct stat stats;
char *name, *backing, *limit = NULL;
int fixedsize = 0, rawparent = 0;
if (type != TD_TYPE_VHD) {
fprintf(stderr, "Cannot create snapshot of %s image type\n",
td_disk_types[type]);
return EINVAL;
}
while ((c = getopt(argc, argv, "hbml:")) != -1) {
switch(c) {
case 'b':
fixedsize = 1;
break;
case 'm':
rawparent = 1;
break;
case 'l':
limit = optarg;
break;
case 'h':
err = 0;
goto usage;
default:
err = EINVAL;
goto usage;
}
}
if (optind != (argc - 2)) {
err = EINVAL;
goto usage;
}
name = argv[optind++];
backing = argv[optind++];
if (strnlen(name, MAX_NAME_LEN) == MAX_NAME_LEN ||
strnlen(backing, MAX_NAME_LEN) == MAX_NAME_LEN) {
fprintf(stderr, "Device name too long\n");
return ENAMETOOLONG;
}
if (stat(backing, &stats) == -1) {
fprintf(stderr, "File %s not found\n", backing);
return errno;
}
cargc = 0;
memset(cargv, 0, sizeof(cargv));
cargv[cargc++] = "snapshot";
cargv[cargc++] = "-n";
cargv[cargc++] = name;
cargv[cargc++] = "-p";
cargv[cargc++] = backing;
if (fixedsize)
cargv[cargc++] = "-b";
if (rawparent)
cargv[cargc++] = "-m";
if (limit) {
cargv[cargc++] = "-l";
cargv[cargc++] = limit;
}
return vhd_util_snapshot(cargc, cargv);
usage:
fprintf(stderr, "usage: td-util snapshot %s [-h help] [-m parent_raw] "
"[-b file_is_fixed_size] [-l snapshot depth limit] "
"<FILENAME> <BACKING_FILENAME>\n", td_disk_types[type]);
return err;
}
int
td_coalesce(int type, int argc, char *argv[])
{
int c, ret, cargc;
char *name, *pname, *cargv[3];
if (type != TD_TYPE_VHD) {
fprintf(stderr, "Cannot create snapshot of %s image type\n",
td_disk_types[type]);
return EINVAL;
}
while ((c = getopt(argc, argv, "h")) != -1) {
switch(c) {
default:
fprintf(stderr, "Unknown option %c\n", (char)c);
case 'h':
goto usage;
}
}
if (optind != (argc - 1))
goto usage;
name = argv[optind++];
if (strnlen(name, MAX_NAME_LEN) == MAX_NAME_LEN) {
fprintf(stderr, "Device name too long\n");
return ENAMETOOLONG;
}
cargc = 0;
memset(cargv, 0, sizeof(cargv));
cargv[cargc++] = "coalesce";
cargv[cargc++] = "-n";
cargv[cargc++] = name;
ret = vhd_util_coalesce(cargc, cargv);
if (ret)
printf("coalesce failed: %d\n", ret);
return ret;
usage:
fprintf(stderr, "usage: td-util coalesce %s [-h help] "
"<FILENAME>\n", td_disk_types[type]);
return EINVAL;
}
int
td_query(int type, int argc, char *argv[])
{
char *name;
int c, size = 0, parent = 0, fields = 0, depth = 0, err = 0;
while ((c = getopt(argc, argv, "hvpfd")) != -1) {
switch(c) {
case 'v':
size = 1;
break;
case 'p':
parent = 1;
break;
case 'f':
fields = 1;
break;
case 'd':
depth = 1;
break;
case 'h':
err = 0;
goto usage;
default:
err = EINVAL;
goto usage;
}
}
if (optind != (argc - 1)) {
err = EINVAL;
goto usage;
}
name = argv[optind++];
if (strnlen(name, MAX_NAME_LEN) == MAX_NAME_LEN) {
fprintf(stderr, "Device name too long\n");
return ENAMETOOLONG;
}
if (type == TD_TYPE_VHD) {
vhd_context_t vhd;
err = vhd_open(&vhd, name, VHD_OPEN_RDONLY);
if (err) {
printf("failed opening %s: %d\n", name, err);
return err;
}
if (size)
printf("%"PRIu64"\n", vhd.footer.curr_size >> 20);
if (parent) {
if (vhd.footer.type != HD_TYPE_DIFF)
printf("%s has no parent\n", name);
else {
char *pname;
err = vhd_parent_locator_get(&vhd, &pname);
if (err)
printf("failed getting parent: %d\n",
err);
else {
printf("%s\n", pname);
free(pname);
}
}
}
if (fields) {
int ret, hidden;
ret = vhd_hidden(&vhd, &hidden);
if (ret) {
printf("failed checking 'hidden' field: %d\n",
ret);
err = (err ? : ret);
} else
printf("%s: %d\n",
td_vdi_fields[TD_FIELD_HIDDEN].name,
hidden);
}
if (depth) {
int ret, length;
ret = vhd_chain_depth(&vhd, &length);
if (ret)
printf("error checking chain depth: %d\n", ret);
else
printf("chain depth: %d\n", length);
err = (err ? : ret);
}
vhd_close(&vhd);
} else if (type == TD_TYPE_AIO) {
if (size) {
int fd;
uint64_t secs;
uint32_t ssize;
fd = open(name, O_RDONLY | O_LARGEFILE);
if (fd == -1) {
printf("failed opening %s: %d\n", name, errno);
return -errno;
}
err = tapdisk_get_image_size(fd, &secs, &ssize);
close(fd);
if (err) {
printf("failed getting size for %s: %d\n:",
name, err);
return err;
}
printf("%"PRIu64"\n", secs >> 11);
}
if (parent)
printf("%s has no parent\n", name);
if (fields) {
int i;
for (i = 0; i < TD_FIELD_INVALID; i++)
printf("%s: 0\n", td_vdi_fields[i].name);
}
}
return err;
usage:
fprintf(stderr, "usage: td-util query %s [-h help] [-v virtsize] "
"[-p parent] [-f fields] <FILENAME>\n", td_disk_types[type]);
return err;
}
int
td_set_field(int type, int argc, char *argv[])
{
int ret, i, c, cargc;
struct vdi_field *field;
char *name, *value, *cargv[7];
if (type != TD_TYPE_VHD) {
fprintf(stderr, "Cannot set fields of %s images\n",
td_disk_types[type]);
return EINVAL;
}
while ((c = getopt(argc, argv, "h")) != -1) {
switch(c) {
default:
fprintf(stderr, "Unknown option %c\n", (char)c);
case 'h':
goto usage;
}
}
if (optind != (argc - 3))
goto usage;
name = argv[optind++];
field = get_field(argv[optind]);
if (!field || field->id != TD_FIELD_HIDDEN) {
fprintf(stderr, "Invalid field %s\n", argv[optind]);
goto usage;
}
value = argv[++optind];
cargc = 0;
memset(cargv, 0, sizeof(cargv));
cargv[cargc++] = "set";
cargv[cargc++] = "-n";
cargv[cargc++] = name;
cargv[cargc++] = "-f";
cargv[cargc++] = field->name;
cargv[cargc++] = "-v";
cargv[cargc++] = value;
return vhd_util_set_field(cargc, cargv);
usage:
fprintf(stderr, "usage: td-util set %s [-h help] "
"<FILENAME> <FIELD> <VALUE>\n", td_disk_types[type]);
print_field_names();
return EINVAL;
}
int
main(int argc, char *argv[])
{
char **cargv;
struct command *cmd;
int cargc, i, type = -1, ret = 0;
#ifdef CORE_DUMP
struct rlimit rlim;
rlim.rlim_cur = RLIM_INFINITY;
rlim.rlim_max = RLIM_INFINITY;
if (setrlimit(RLIMIT_CORE, &rlim) < 0)
fprintf(stderr, "setrlimit failed: %d\n", errno);
#endif
if (argc < 2)
help();
cargc = argc - 1;
cmd = get_command(argv[1]);
if (!cmd) {
fprintf(stderr, "invalid COMMAND %s\n", argv[1]);
help();
}
if (cmd->needs_type) {
if (argc < 3) {
fprintf(stderr, "td-util %s requires a TYPE\n",
cmd->name);
print_disk_types();
exit(-1);
}
type = get_driver_type(argv[2]);
if (type < 0) {
fprintf(stderr, "invalid TYPE '%s'.\n", argv[2]);
print_disk_types();
exit(-1);
}
--cargc;
}
cargv = malloc(sizeof(char *) * cargc);
if (!cargv)
exit(ENOMEM);
cargv[0] = cmd->name;
for (i = 1; i < cargc; i++)
cargv[i] = argv[i + (argc - cargc)];
switch(cmd->id) {
case TD_CMD_CREATE:
ret = td_create(type, cargc, cargv);
break;
case TD_CMD_SNAPSHOT:
ret = td_snapshot(type, cargc, cargv);
break;
/*
case TD_CMD_COALESCE:
ret = td_coalesce(type, cargc, cargv);
break;
*/
case TD_CMD_QUERY:
ret = td_query(type, cargc, cargv);
break;
/*
case TD_CMD_RESIZE:
ret = td_resize(type, cargc, cargv);
break;
*/
case TD_CMD_SET:
ret = td_set_field(type, cargc, cargv);
break;
/*
case TD_CMD_REPAIR:
ret = td_repair(type, cargc, cargv);
break;
case TD_CMD_FILL:
ret = td_fill(type, cargc, cargv);
break;
case TD_CMD_READ:
ret = td_read(type, cargc, cargv);
break;
*/
default:
case TD_CMD_INVALID:
ret = EINVAL;
break;
}
free(cargv);
return (ret >= 0 ? ret : -ret);
}