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qemu/qemu-img.c
Federico Simoncelli 661a0f712b qemu-img: Add cache command line option 
qemu-img currently writes disk images using writeback and filling
up the cache buffers which are then flushed by the kernel preventing
other processes from accessing the storage.
This is particularly bad in cluster environments where time-based
algorithms might be in place and accessing the storage within
certain timeouts is critical.
This patch adds the option to choose a cache method when writing
disk images.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-07-05 11:23:29 +02:00

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/*
* QEMU disk image utility
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "qemu-option.h"
#include "qemu-error.h"
#include "osdep.h"
#include "sysemu.h"
#include "block_int.h"
#include <stdio.h>
#ifdef _WIN32
#include <windows.h>
#endif
typedef struct img_cmd_t {
const char *name;
int (*handler)(int argc, char **argv);
} img_cmd_t;
/* Default to cache=writeback as data integrity is not important for qemu-tcg. */
#define BDRV_O_FLAGS BDRV_O_CACHE_WB
#define BDRV_DEFAULT_CACHE "writeback"
static void format_print(void *opaque, const char *name)
{
printf(" %s", name);
}
/* Please keep in synch with qemu-img.texi */
static void help(void)
{
const char *help_msg =
"qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice Bellard\n"
"usage: qemu-img command [command options]\n"
"QEMU disk image utility\n"
"\n"
"Command syntax:\n"
#define DEF(option, callback, arg_string) \
" " arg_string "\n"
#include "qemu-img-cmds.h"
#undef DEF
#undef GEN_DOCS
"\n"
"Command parameters:\n"
" 'filename' is a disk image filename\n"
" 'fmt' is the disk image format. It is guessed automatically in most cases\n"
" 'cache' is the cache mode used to write the output disk image, the valid\n"
" options are: 'none', 'writeback' (default), 'writethrough' and 'unsafe'\n"
" 'size' is the disk image size in bytes. Optional suffixes\n"
" 'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M)\n"
" and T (terabyte, 1024G) are supported. 'b' is ignored.\n"
" 'output_filename' is the destination disk image filename\n"
" 'output_fmt' is the destination format\n"
" 'options' is a comma separated list of format specific options in a\n"
" name=value format. Use -o ? for an overview of the options supported by the\n"
" used format\n"
" '-c' indicates that target image must be compressed (qcow format only)\n"
" '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"
" match exactly. The image doesn't need a working backing file before\n"
" rebasing in this case (useful for renaming the backing file)\n"
" '-h' with or without a command shows this help and lists the supported formats\n"
" '-p' show progress of command (only certain commands)\n"
"\n"
"Parameters to snapshot subcommand:\n"
" 'snapshot' is the name of the snapshot to create, apply or delete\n"
" '-a' applies a snapshot (revert disk to saved state)\n"
" '-c' creates a snapshot\n"
" '-d' deletes a snapshot\n"
" '-l' lists all snapshots in the given image\n";
printf("%s\nSupported formats:", help_msg);
bdrv_iterate_format(format_print, NULL);
printf("\n");
exit(1);
}
#if defined(WIN32)
/* XXX: put correct support for win32 */
static int read_password(char *buf, int buf_size)
{
int c, i;
printf("Password: ");
fflush(stdout);
i = 0;
for(;;) {
c = getchar();
if (c == '\n')
break;
if (i < (buf_size - 1))
buf[i++] = c;
}
buf[i] = '\0';
return 0;
}
#else
#include <termios.h>
static struct termios oldtty;
static void term_exit(void)
{
tcsetattr (0, TCSANOW, &oldtty);
}
static void term_init(void)
{
struct termios tty;
tcgetattr (0, &tty);
oldtty = tty;
tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
|INLCR|IGNCR|ICRNL|IXON);
tty.c_oflag |= OPOST;
tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
tty.c_cflag &= ~(CSIZE|PARENB);
tty.c_cflag |= CS8;
tty.c_cc[VMIN] = 1;
tty.c_cc[VTIME] = 0;
tcsetattr (0, TCSANOW, &tty);
atexit(term_exit);
}
static int read_password(char *buf, int buf_size)
{
uint8_t ch;
int i, ret;
printf("password: ");
fflush(stdout);
term_init();
i = 0;
for(;;) {
ret = read(0, &ch, 1);
if (ret == -1) {
if (errno == EAGAIN || errno == EINTR) {
continue;
} else {
ret = -1;
break;
}
} else if (ret == 0) {
ret = -1;
break;
} else {
if (ch == '\r') {
ret = 0;
break;
}
if (i < (buf_size - 1))
buf[i++] = ch;
}
}
term_exit();
buf[i] = '\0';
printf("\n");
return ret;
}
#endif
static int set_cache_flag(const char *mode, int *flags)
{
*flags &= ~BDRV_O_CACHE_MASK;
if (!strcmp(mode, "none") || !strcmp(mode, "off")) {
*flags |= BDRV_O_CACHE_WB;
*flags |= BDRV_O_NOCACHE;
} else if (!strcmp(mode, "writeback")) {
*flags |= BDRV_O_CACHE_WB;
} else if (!strcmp(mode, "unsafe")) {
*flags |= BDRV_O_CACHE_WB;
*flags |= BDRV_O_NO_FLUSH;
} else if (!strcmp(mode, "writethrough")) {
/* this is the default */
} else {
return -1;
}
return 0;
}
static int print_block_option_help(const char *filename, const char *fmt)
{
BlockDriver *drv, *proto_drv;
QEMUOptionParameter *create_options = NULL;
/* Find driver and parse its options */
drv = bdrv_find_format(fmt);
if (!drv) {
error_report("Unknown file format '%s'", fmt);
return 1;
}
proto_drv = bdrv_find_protocol(filename);
if (!proto_drv) {
error_report("Unknown protocol '%s'", filename);
return 1;
}
create_options = append_option_parameters(create_options,
drv->create_options);
create_options = append_option_parameters(create_options,
proto_drv->create_options);
print_option_help(create_options);
free_option_parameters(create_options);
return 0;
}
static BlockDriverState *bdrv_new_open(const char *filename,
const char *fmt,
int flags)
{
BlockDriverState *bs;
BlockDriver *drv;
char password[256];
int ret;
bs = bdrv_new("image");
if (fmt) {
drv = bdrv_find_format(fmt);
if (!drv) {
error_report("Unknown file format '%s'", fmt);
goto fail;
}
} else {
drv = NULL;
}
ret = bdrv_open(bs, filename, flags, drv);
if (ret < 0) {
error_report("Could not open '%s': %s", filename, strerror(-ret));
goto fail;
}
if (bdrv_is_encrypted(bs)) {
printf("Disk image '%s' is encrypted.\n", filename);
if (read_password(password, sizeof(password)) < 0) {
error_report("No password given");
goto fail;
}
if (bdrv_set_key(bs, password) < 0) {
error_report("invalid password");
goto fail;
}
}
return bs;
fail:
if (bs) {
bdrv_delete(bs);
}
return NULL;
}
static int add_old_style_options(const char *fmt, QEMUOptionParameter *list,
const char *base_filename,
const char *base_fmt)
{
if (base_filename) {
if (set_option_parameter(list, BLOCK_OPT_BACKING_FILE, base_filename)) {
error_report("Backing file not supported for file format '%s'",
fmt);
return -1;
}
}
if (base_fmt) {
if (set_option_parameter(list, BLOCK_OPT_BACKING_FMT, base_fmt)) {
error_report("Backing file format not supported for file "
"format '%s'", fmt);
return -1;
}
}
return 0;
}
static int img_create(int argc, char **argv)
{
int c, ret = 0;
uint64_t img_size = -1;
const char *fmt = "raw";
const char *base_fmt = NULL;
const char *filename;
const char *base_filename = NULL;
char *options = NULL;
for(;;) {
c = getopt(argc, argv, "F:b:f:he6o:");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
break;
case 'F':
base_fmt = optarg;
break;
case 'b':
base_filename = optarg;
break;
case 'f':
fmt = optarg;
break;
case 'e':
error_report("option -e is deprecated, please use \'-o "
"encryption\' instead!");
return 1;
case '6':
error_report("option -6 is deprecated, please use \'-o "
"compat6\' instead!");
return 1;
case 'o':
options = optarg;
break;
}
}
/* Get the filename */
if (optind >= argc) {
help();
}
filename = argv[optind++];
/* Get image size, if specified */
if (optind < argc) {
int64_t sval;
sval = strtosz_suffix(argv[optind++], NULL, STRTOSZ_DEFSUFFIX_B);
if (sval < 0) {
error_report("Invalid image size specified! You may use k, M, G or "
"T suffixes for ");
error_report("kilobytes, megabytes, gigabytes and terabytes.");
ret = -1;
goto out;
}
img_size = (uint64_t)sval;
}
if (options && !strcmp(options, "?")) {
ret = print_block_option_help(filename, fmt);
goto out;
}
ret = bdrv_img_create(filename, fmt, base_filename, base_fmt,
options, img_size, BDRV_O_FLAGS);
out:
if (ret) {
return 1;
}
return 0;
}
/*
* Checks an image for consistency. Exit codes:
*
* 0 - Check completed, image is good
* 1 - Check not completed because of internal errors
* 2 - Check completed, image is corrupted
* 3 - Check completed, image has leaked clusters, but is good otherwise
*/
static int img_check(int argc, char **argv)
{
int c, ret;
const char *filename, *fmt;
BlockDriverState *bs;
BdrvCheckResult result;
fmt = NULL;
for(;;) {
c = getopt(argc, argv, "f:h");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
}
}
if (optind >= argc) {
help();
}
filename = argv[optind++];
bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS);
if (!bs) {
return 1;
}
ret = bdrv_check(bs, &result);
if (ret == -ENOTSUP) {
error_report("This image format does not support checks");
bdrv_delete(bs);
return 1;
}
if (!(result.corruptions || result.leaks || result.check_errors)) {
printf("No errors were found on the image.\n");
} else {
if (result.corruptions) {
printf("\n%d errors were found on the image.\n"
"Data may be corrupted, or further writes to the image "
"may corrupt it.\n",
result.corruptions);
}
if (result.leaks) {
printf("\n%d leaked clusters were found on the image.\n"
"This means waste of disk space, but no harm to data.\n",
result.leaks);
}
if (result.check_errors) {
printf("\n%d internal errors have occurred during the check.\n",
result.check_errors);
}
}
bdrv_delete(bs);
if (ret < 0 || result.check_errors) {
printf("\nAn error has occurred during the check: %s\n"
"The check is not complete and may have missed error.\n",
strerror(-ret));
return 1;
}
if (result.corruptions) {
return 2;
} else if (result.leaks) {
return 3;
} else {
return 0;
}
}
static int img_commit(int argc, char **argv)
{
int c, ret, flags;
const char *filename, *fmt, *cache;
BlockDriverState *bs;
fmt = NULL;
cache = BDRV_DEFAULT_CACHE;
for(;;) {
c = getopt(argc, argv, "f:ht:");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
case 't':
cache = optarg;
break;
}
}
if (optind >= argc) {
help();
}
filename = argv[optind++];
flags = BDRV_O_RDWR;
ret = set_cache_flag(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
return -1;
}
bs = bdrv_new_open(filename, fmt, flags);
if (!bs) {
return 1;
}
ret = bdrv_commit(bs);
switch(ret) {
case 0:
printf("Image committed.\n");
break;
case -ENOENT:
error_report("No disk inserted");
break;
case -EACCES:
error_report("Image is read-only");
break;
case -ENOTSUP:
error_report("Image is already committed");
break;
default:
error_report("Error while committing image");
break;
}
bdrv_delete(bs);
if (ret) {
return 1;
}
return 0;
}
/*
* Checks whether the sector is not a zero sector.
*
* Attention! The len must be a multiple of 4 * sizeof(long) due to
* restriction of optimizations in this function.
*/
static int is_not_zero(const uint8_t *sector, int len)
{
/*
* Use long as the biggest available internal data type that fits into the
* CPU register and unroll the loop to smooth out the effect of memory
* latency.
*/
int i;
long d0, d1, d2, d3;
const long * const data = (const long *) sector;
len /= sizeof(long);
for(i = 0; i < len; i += 4) {
d0 = data[i + 0];
d1 = data[i + 1];
d2 = data[i + 2];
d3 = data[i + 3];
if (d0 || d1 || d2 || d3) {
return 1;
}
}
return 0;
}
/*
* Returns true iff the first sector pointed to by 'buf' contains at least
* a non-NUL byte.
*
* 'pnum' is set to the number of sectors (including and immediately following
* the first one) that are known to be in the same allocated/unallocated state.
*/
static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
{
int v, i;
if (n <= 0) {
*pnum = 0;
return 0;
}
v = is_not_zero(buf, 512);
for(i = 1; i < n; i++) {
buf += 512;
if (v != is_not_zero(buf, 512))
break;
}
*pnum = i;
return v;
}
/*
* Compares two buffers sector by sector. Returns 0 if the first sector of both
* buffers matches, non-zero otherwise.
*
* pnum is set to the number of sectors (including and immediately following
* the first one) that are known to have the same comparison result
*/
static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
int *pnum)
{
int res, i;
if (n <= 0) {
*pnum = 0;
return 0;
}
res = !!memcmp(buf1, buf2, 512);
for(i = 1; i < n; i++) {
buf1 += 512;
buf2 += 512;
if (!!memcmp(buf1, buf2, 512) != res) {
break;
}
}
*pnum = i;
return res;
}
#define IO_BUF_SIZE (2 * 1024 * 1024)
static int img_convert(int argc, char **argv)
{
int c, ret = 0, n, n1, bs_n, bs_i, compress, cluster_size, cluster_sectors;
int progress = 0, flags;
const char *fmt, *out_fmt, *cache, *out_baseimg, *out_filename;
BlockDriver *drv, *proto_drv;
BlockDriverState **bs = NULL, *out_bs = NULL;
int64_t total_sectors, nb_sectors, sector_num, bs_offset;
uint64_t bs_sectors;
uint8_t * buf = NULL;
const uint8_t *buf1;
BlockDriverInfo bdi;
QEMUOptionParameter *param = NULL, *create_options = NULL;
QEMUOptionParameter *out_baseimg_param;
char *options = NULL;
const char *snapshot_name = NULL;
float local_progress;
fmt = NULL;
out_fmt = "raw";
cache = "unsafe";
out_baseimg = NULL;
compress = 0;
for(;;) {
c = getopt(argc, argv, "f:O:B:s:hce6o:pt:");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
case 'O':
out_fmt = optarg;
break;
case 'B':
out_baseimg = optarg;
break;
case 'c':
compress = 1;
break;
case 'e':
error_report("option -e is deprecated, please use \'-o "
"encryption\' instead!");
return 1;
case '6':
error_report("option -6 is deprecated, please use \'-o "
"compat6\' instead!");
return 1;
case 'o':
options = optarg;
break;
case 's':
snapshot_name = optarg;
break;
case 'p':
progress = 1;
break;
case 't':
cache = optarg;
break;
}
}
bs_n = argc - optind - 1;
if (bs_n < 1) {
help();
}
out_filename = argv[argc - 1];
if (options && !strcmp(options, "?")) {
ret = print_block_option_help(out_filename, out_fmt);
goto out;
}
if (bs_n > 1 && out_baseimg) {
error_report("-B makes no sense when concatenating multiple input "
"images");
ret = -1;
goto out;
}
qemu_progress_init(progress, 2.0);
qemu_progress_print(0, 100);
bs = qemu_mallocz(bs_n * sizeof(BlockDriverState *));
total_sectors = 0;
for (bs_i = 0; bs_i < bs_n; bs_i++) {
bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, BDRV_O_FLAGS);
if (!bs[bs_i]) {
error_report("Could not open '%s'", argv[optind + bs_i]);
ret = -1;
goto out;
}
bdrv_get_geometry(bs[bs_i], &bs_sectors);
total_sectors += bs_sectors;
}
if (snapshot_name != NULL) {
if (bs_n > 1) {
error_report("No support for concatenating multiple snapshot");
ret = -1;
goto out;
}
if (bdrv_snapshot_load_tmp(bs[0], snapshot_name) < 0) {
error_report("Failed to load snapshot");
ret = -1;
goto out;
}
}
/* Find driver and parse its options */
drv = bdrv_find_format(out_fmt);
if (!drv) {
error_report("Unknown file format '%s'", out_fmt);
ret = -1;
goto out;
}
proto_drv = bdrv_find_protocol(out_filename);
if (!proto_drv) {
error_report("Unknown protocol '%s'", out_filename);
ret = -1;
goto out;
}
create_options = append_option_parameters(create_options,
drv->create_options);
create_options = append_option_parameters(create_options,
proto_drv->create_options);
if (options) {
param = parse_option_parameters(options, create_options, param);
if (param == NULL) {
error_report("Invalid options for file format '%s'.", out_fmt);
ret = -1;
goto out;
}
} else {
param = parse_option_parameters("", create_options, param);
}
set_option_parameter_int(param, BLOCK_OPT_SIZE, total_sectors * 512);
ret = add_old_style_options(out_fmt, param, out_baseimg, NULL);
if (ret < 0) {
goto out;
}
/* Get backing file name if -o backing_file was used */
out_baseimg_param = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
if (out_baseimg_param) {
out_baseimg = out_baseimg_param->value.s;
}
/* Check if compression is supported */
if (compress) {
QEMUOptionParameter *encryption =
get_option_parameter(param, BLOCK_OPT_ENCRYPT);
if (!drv->bdrv_write_compressed) {
error_report("Compression not supported for this file format");
ret = -1;
goto out;
}
if (encryption && encryption->value.n) {
error_report("Compression and encryption not supported at "
"the same time");
ret = -1;
goto out;
}
}
/* Create the new image */
ret = bdrv_create(drv, out_filename, param);
if (ret < 0) {
if (ret == -ENOTSUP) {
error_report("Formatting not supported for file format '%s'",
out_fmt);
} else if (ret == -EFBIG) {
error_report("The image size is too large for file format '%s'",
out_fmt);
} else {
error_report("%s: error while converting %s: %s",
out_filename, out_fmt, strerror(-ret));
}
goto out;
}
flags = BDRV_O_RDWR;
ret = set_cache_flag(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
return -1;
}
out_bs = bdrv_new_open(out_filename, out_fmt, flags);
if (!out_bs) {
ret = -1;
goto out;
}
bs_i = 0;
bs_offset = 0;
bdrv_get_geometry(bs[0], &bs_sectors);
buf = qemu_malloc(IO_BUF_SIZE);
if (compress) {
ret = bdrv_get_info(out_bs, &bdi);
if (ret < 0) {
error_report("could not get block driver info");
goto out;
}
cluster_size = bdi.cluster_size;
if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE) {
error_report("invalid cluster size");
ret = -1;
goto out;
}
cluster_sectors = cluster_size >> 9;
sector_num = 0;
nb_sectors = total_sectors;
local_progress = (float)100 /
(nb_sectors / MIN(nb_sectors, cluster_sectors));
for(;;) {
int64_t bs_num;
int remainder;
uint8_t *buf2;
nb_sectors = total_sectors - sector_num;
if (nb_sectors <= 0)
break;
if (nb_sectors >= cluster_sectors)
n = cluster_sectors;
else
n = nb_sectors;
bs_num = sector_num - bs_offset;
assert (bs_num >= 0);
remainder = n;
buf2 = buf;
while (remainder > 0) {
int nlow;
while (bs_num == bs_sectors) {
bs_i++;
assert (bs_i < bs_n);
bs_offset += bs_sectors;
bdrv_get_geometry(bs[bs_i], &bs_sectors);
bs_num = 0;
/* printf("changing part: sector_num=%" PRId64 ", "
"bs_i=%d, bs_offset=%" PRId64 ", bs_sectors=%" PRId64
"\n", sector_num, bs_i, bs_offset, bs_sectors); */
}
assert (bs_num < bs_sectors);
nlow = (remainder > bs_sectors - bs_num) ? bs_sectors - bs_num : remainder;
ret = bdrv_read(bs[bs_i], bs_num, buf2, nlow);
if (ret < 0) {
error_report("error while reading");
goto out;
}
buf2 += nlow * 512;
bs_num += nlow;
remainder -= nlow;
}
assert (remainder == 0);
if (n < cluster_sectors) {
memset(buf + n * 512, 0, cluster_size - n * 512);
}
if (is_not_zero(buf, cluster_size)) {
ret = bdrv_write_compressed(out_bs, sector_num, buf,
cluster_sectors);
if (ret != 0) {
error_report("error while compressing sector %" PRId64,
sector_num);
goto out;
}
}
sector_num += n;
qemu_progress_print(local_progress, 100);
}
/* signal EOF to align */
bdrv_write_compressed(out_bs, 0, NULL, 0);
} else {
int has_zero_init = bdrv_has_zero_init(out_bs);
sector_num = 0; // total number of sectors converted so far
nb_sectors = total_sectors - sector_num;
local_progress = (float)100 /
(nb_sectors / MIN(nb_sectors, IO_BUF_SIZE / 512));
for(;;) {
nb_sectors = total_sectors - sector_num;
if (nb_sectors <= 0) {
break;
}
if (nb_sectors >= (IO_BUF_SIZE / 512)) {
n = (IO_BUF_SIZE / 512);
} else {
n = nb_sectors;
}
while (sector_num - bs_offset >= bs_sectors) {
bs_i ++;
assert (bs_i < bs_n);
bs_offset += bs_sectors;
bdrv_get_geometry(bs[bs_i], &bs_sectors);
/* printf("changing part: sector_num=%" PRId64 ", bs_i=%d, "
"bs_offset=%" PRId64 ", bs_sectors=%" PRId64 "\n",
sector_num, bs_i, bs_offset, bs_sectors); */
}
if (n > bs_offset + bs_sectors - sector_num) {
n = bs_offset + bs_sectors - sector_num;
}
if (has_zero_init) {
/* If the output image is being created as a copy on write image,
assume that sectors which are unallocated in the input image
are present in both the output's and input's base images (no
need to copy them). */
if (out_baseimg) {
if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
n, &n1)) {
sector_num += n1;
continue;
}
/* The next 'n1' sectors are allocated in the input image. Copy
only those as they may be followed by unallocated sectors. */
n = n1;
}
} else {
n1 = n;
}
ret = bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n);
if (ret < 0) {
error_report("error while reading");
goto out;
}
/* NOTE: at the same time we convert, we do not write zero
sectors to have a chance to compress the image. Ideally, we
should add a specific call to have the info to go faster */
buf1 = buf;
while (n > 0) {
/* If the output image is being created as a copy on write image,
copy all sectors even the ones containing only NUL bytes,
because they may differ from the sectors in the base image.
If the output is to a host device, we also write out
sectors that are entirely 0, since whatever data was
already there is garbage, not 0s. */
if (!has_zero_init || out_baseimg ||
is_allocated_sectors(buf1, n, &n1)) {
ret = bdrv_write(out_bs, sector_num, buf1, n1);
if (ret < 0) {
error_report("error while writing");
goto out;
}
}
sector_num += n1;
n -= n1;
buf1 += n1 * 512;
}
qemu_progress_print(local_progress, 100);
}
}
out:
qemu_progress_end();
free_option_parameters(create_options);
free_option_parameters(param);
qemu_free(buf);
if (out_bs) {
bdrv_delete(out_bs);
}
if (bs) {
for (bs_i = 0; bs_i < bs_n; bs_i++) {
if (bs[bs_i]) {
bdrv_delete(bs[bs_i]);
}
}
qemu_free(bs);
}
if (ret) {
return 1;
}
return 0;
}
#ifdef _WIN32
static int64_t get_allocated_file_size(const char *filename)
{
typedef DWORD (WINAPI * get_compressed_t)(const char *filename, DWORD *high);
get_compressed_t get_compressed;
struct _stati64 st;
/* WinNT support GetCompressedFileSize to determine allocate size */
get_compressed = (get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"), "GetCompressedFileSizeA");
if (get_compressed) {
DWORD high, low;
low = get_compressed(filename, &high);
if (low != 0xFFFFFFFFlu || GetLastError() == NO_ERROR)
return (((int64_t) high) << 32) + low;
}
if (_stati64(filename, &st) < 0)
return -1;
return st.st_size;
}
#else
static int64_t get_allocated_file_size(const char *filename)
{
struct stat st;
if (stat(filename, &st) < 0)
return -1;
return (int64_t)st.st_blocks * 512;
}
#endif
static void dump_snapshots(BlockDriverState *bs)
{
QEMUSnapshotInfo *sn_tab, *sn;
int nb_sns, i;
char buf[256];
nb_sns = bdrv_snapshot_list(bs, &sn_tab);
if (nb_sns <= 0)
return;
printf("Snapshot list:\n");
printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
for(i = 0; i < nb_sns; i++) {
sn = &sn_tab[i];
printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));
}
qemu_free(sn_tab);
}
static int img_info(int argc, char **argv)
{
int c;
const char *filename, *fmt;
BlockDriverState *bs;
char fmt_name[128], size_buf[128], dsize_buf[128];
uint64_t total_sectors;
int64_t allocated_size;
char backing_filename[1024];
char backing_filename2[1024];
BlockDriverInfo bdi;
fmt = NULL;
for(;;) {
c = getopt(argc, argv, "f:h");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
}
}
if (optind >= argc) {
help();
}
filename = argv[optind++];
bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING);
if (!bs) {
return 1;
}
bdrv_get_format(bs, fmt_name, sizeof(fmt_name));
bdrv_get_geometry(bs, &total_sectors);
get_human_readable_size(size_buf, sizeof(size_buf), total_sectors * 512);
allocated_size = get_allocated_file_size(filename);
if (allocated_size < 0) {
snprintf(dsize_buf, sizeof(dsize_buf), "unavailable");
} else {
get_human_readable_size(dsize_buf, sizeof(dsize_buf),
allocated_size);
}
printf("image: %s\n"
"file format: %s\n"
"virtual size: %s (%" PRId64 " bytes)\n"
"disk size: %s\n",
filename, fmt_name, size_buf,
(total_sectors * 512),
dsize_buf);
if (bdrv_is_encrypted(bs)) {
printf("encrypted: yes\n");
}
if (bdrv_get_info(bs, &bdi) >= 0) {
if (bdi.cluster_size != 0) {
printf("cluster_size: %d\n", bdi.cluster_size);
}
}
bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));
if (backing_filename[0] != '\0') {
path_combine(backing_filename2, sizeof(backing_filename2),
filename, backing_filename);
printf("backing file: %s (actual path: %s)\n",
backing_filename,
backing_filename2);
}
dump_snapshots(bs);
bdrv_delete(bs);
return 0;
}
#define SNAPSHOT_LIST 1
#define SNAPSHOT_CREATE 2
#define SNAPSHOT_APPLY 3
#define SNAPSHOT_DELETE 4
static int img_snapshot(int argc, char **argv)
{
BlockDriverState *bs;
QEMUSnapshotInfo sn;
char *filename, *snapshot_name = NULL;
int c, ret = 0, bdrv_oflags;
int action = 0;
qemu_timeval tv;
bdrv_oflags = BDRV_O_FLAGS | BDRV_O_RDWR;
/* Parse commandline parameters */
for(;;) {
c = getopt(argc, argv, "la:c:d:h");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
return 0;
case 'l':
if (action) {
help();
return 0;
}
action = SNAPSHOT_LIST;
bdrv_oflags &= ~BDRV_O_RDWR; /* no need for RW */
break;
case 'a':
if (action) {
help();
return 0;
}
action = SNAPSHOT_APPLY;
snapshot_name = optarg;
break;
case 'c':
if (action) {
help();
return 0;
}
action = SNAPSHOT_CREATE;
snapshot_name = optarg;
break;
case 'd':
if (action) {
help();
return 0;
}
action = SNAPSHOT_DELETE;
snapshot_name = optarg;
break;
}
}
if (optind >= argc) {
help();
}
filename = argv[optind++];
/* Open the image */
bs = bdrv_new_open(filename, NULL, bdrv_oflags);
if (!bs) {
return 1;
}
/* Perform the requested action */
switch(action) {
case SNAPSHOT_LIST:
dump_snapshots(bs);
break;
case SNAPSHOT_CREATE:
memset(&sn, 0, sizeof(sn));
pstrcpy(sn.name, sizeof(sn.name), snapshot_name);
qemu_gettimeofday(&tv);
sn.date_sec = tv.tv_sec;
sn.date_nsec = tv.tv_usec * 1000;
ret = bdrv_snapshot_create(bs, &sn);
if (ret) {
error_report("Could not create snapshot '%s': %d (%s)",
snapshot_name, ret, strerror(-ret));
}
break;
case SNAPSHOT_APPLY:
ret = bdrv_snapshot_goto(bs, snapshot_name);
if (ret) {
error_report("Could not apply snapshot '%s': %d (%s)",
snapshot_name, ret, strerror(-ret));
}
break;
case SNAPSHOT_DELETE:
ret = bdrv_snapshot_delete(bs, snapshot_name);
if (ret) {
error_report("Could not delete snapshot '%s': %d (%s)",
snapshot_name, ret, strerror(-ret));
}
break;
}
/* Cleanup */
bdrv_delete(bs);
if (ret) {
return 1;
}
return 0;
}
static int img_rebase(int argc, char **argv)
{
BlockDriverState *bs, *bs_old_backing = NULL, *bs_new_backing = NULL;
BlockDriver *old_backing_drv, *new_backing_drv;
char *filename;
const char *fmt, *cache, *out_basefmt, *out_baseimg;
int c, flags, ret;
int unsafe = 0;
int progress = 0;
/* Parse commandline parameters */
fmt = NULL;
cache = BDRV_DEFAULT_CACHE;
out_baseimg = NULL;
out_basefmt = NULL;
for(;;) {
c = getopt(argc, argv, "uhf:F:b:pt:");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
return 0;
case 'f':
fmt = optarg;
break;
case 'F':
out_basefmt = optarg;
break;
case 'b':
out_baseimg = optarg;
break;
case 'u':
unsafe = 1;
break;
case 'p':
progress = 1;
break;
case 't':
cache = optarg;
break;
}
}
if ((optind >= argc) || (!unsafe && !out_baseimg)) {
help();
}
filename = argv[optind++];
qemu_progress_init(progress, 2.0);
qemu_progress_print(0, 100);
flags = BDRV_O_RDWR | (unsafe ? BDRV_O_NO_BACKING : 0);
ret = set_cache_flag(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
return -1;
}
/*
* Open the images.
*
* Ignore the old backing file for unsafe rebase in case we want to correct
* the reference to a renamed or moved backing file.
*/
bs = bdrv_new_open(filename, fmt, flags);
if (!bs) {
return 1;
}
/* Find the right drivers for the backing files */
old_backing_drv = NULL;
new_backing_drv = NULL;
if (!unsafe && bs->backing_format[0] != '\0') {
old_backing_drv = bdrv_find_format(bs->backing_format);
if (old_backing_drv == NULL) {
error_report("Invalid format name: '%s'", bs->backing_format);
ret = -1;
goto out;
}
}
if (out_basefmt != NULL) {
new_backing_drv = bdrv_find_format(out_basefmt);
if (new_backing_drv == NULL) {
error_report("Invalid format name: '%s'", out_basefmt);
ret = -1;
goto out;
}
}
/* For safe rebasing we need to compare old and new backing file */
if (unsafe) {
/* Make the compiler happy */
bs_old_backing = NULL;
bs_new_backing = NULL;
} else {
char backing_name[1024];
bs_old_backing = bdrv_new("old_backing");
bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
ret = bdrv_open(bs_old_backing, backing_name, BDRV_O_FLAGS,
old_backing_drv);
if (ret) {
error_report("Could not open old backing file '%s'", backing_name);
goto out;
}
bs_new_backing = bdrv_new("new_backing");
ret = bdrv_open(bs_new_backing, out_baseimg, BDRV_O_FLAGS,
new_backing_drv);
if (ret) {
error_report("Could not open new backing file '%s'", out_baseimg);
goto out;
}
}
/*
* Check each unallocated cluster in the COW file. If it is unallocated,
* accesses go to the backing file. We must therefore compare this cluster
* in the old and new backing file, and if they differ we need to copy it
* from the old backing file into the COW file.
*
* If qemu-img crashes during this step, no harm is done. The content of
* the image is the same as the original one at any time.
*/
if (!unsafe) {
uint64_t num_sectors;
uint64_t sector;
int n;
uint8_t * buf_old;
uint8_t * buf_new;
float local_progress;
buf_old = qemu_malloc(IO_BUF_SIZE);
buf_new = qemu_malloc(IO_BUF_SIZE);
bdrv_get_geometry(bs, &num_sectors);
local_progress = (float)100 /
(num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
for (sector = 0; sector < num_sectors; sector += n) {
/* How many sectors can we handle with the next read? */
if (sector + (IO_BUF_SIZE / 512) <= num_sectors) {
n = (IO_BUF_SIZE / 512);
} else {
n = num_sectors - sector;
}
/* If the cluster is allocated, we don't need to take action */
ret = bdrv_is_allocated(bs, sector, n, &n);
if (ret) {
continue;
}
/* Read old and new backing file */
ret = bdrv_read(bs_old_backing, sector, buf_old, n);
if (ret < 0) {
error_report("error while reading from old backing file");
goto out;
}
ret = bdrv_read(bs_new_backing, sector, buf_new, n);
if (ret < 0) {
error_report("error while reading from new backing file");
goto out;
}
/* If they differ, we need to write to the COW file */
uint64_t written = 0;
while (written < n) {
int pnum;
if (compare_sectors(buf_old + written * 512,
buf_new + written * 512, n - written, &pnum))
{
ret = bdrv_write(bs, sector + written,
buf_old + written * 512, pnum);
if (ret < 0) {
error_report("Error while writing to COW image: %s",
strerror(-ret));
goto out;
}
}
written += pnum;
}
qemu_progress_print(local_progress, 100);
}
qemu_free(buf_old);
qemu_free(buf_new);
}
/*
* Change the backing file. All clusters that are different from the old
* backing file are overwritten in the COW file now, so the visible content
* doesn't change when we switch the backing file.
*/
ret = bdrv_change_backing_file(bs, out_baseimg, out_basefmt);
if (ret == -ENOSPC) {
error_report("Could not change the backing file to '%s': No "
"space left in the file header", out_baseimg);
} else if (ret < 0) {
error_report("Could not change the backing file to '%s': %s",
out_baseimg, strerror(-ret));
}
qemu_progress_print(100, 0);
/*
* TODO At this point it is possible to check if any clusters that are
* allocated in the COW file are the same in the backing file. If so, they
* could be dropped from the COW file. Don't do this before switching the
* backing file, in case of a crash this would lead to corruption.
*/
out:
qemu_progress_end();
/* Cleanup */
if (!unsafe) {
if (bs_old_backing != NULL) {
bdrv_delete(bs_old_backing);
}
if (bs_new_backing != NULL) {
bdrv_delete(bs_new_backing);
}
}
bdrv_delete(bs);
if (ret) {
return 1;
}
return 0;
}
static int img_resize(int argc, char **argv)
{
int c, ret, relative;
const char *filename, *fmt, *size;
int64_t n, total_size;
BlockDriverState *bs = NULL;
QEMUOptionParameter *param;
QEMUOptionParameter resize_options[] = {
{
.name = BLOCK_OPT_SIZE,
.type = OPT_SIZE,
.help = "Virtual disk size"
},
{ NULL }
};
/* Remove size from argv manually so that negative numbers are not treated
* as options by getopt. */
if (argc < 3) {
help();
return 1;
}
size = argv[--argc];
/* Parse getopt arguments */
fmt = NULL;
for(;;) {
c = getopt(argc, argv, "f:h");
if (c == -1) {
break;
}
switch(c) {
case '?':
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
}
}
if (optind >= argc) {
help();
}
filename = argv[optind++];
/* Choose grow, shrink, or absolute resize mode */
switch (size[0]) {
case '+':
relative = 1;
size++;
break;
case '-':
relative = -1;
size++;
break;
default:
relative = 0;
break;
}
/* Parse size */
param = parse_option_parameters("", resize_options, NULL);
if (set_option_parameter(param, BLOCK_OPT_SIZE, size)) {
/* Error message already printed when size parsing fails */
ret = -1;
goto out;
}
n = get_option_parameter(param, BLOCK_OPT_SIZE)->value.n;
free_option_parameters(param);
bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR);
if (!bs) {
ret = -1;
goto out;
}
if (relative) {
total_size = bdrv_getlength(bs) + n * relative;
} else {
total_size = n;
}
if (total_size <= 0) {
error_report("New image size must be positive");
ret = -1;
goto out;
}
ret = bdrv_truncate(bs, total_size);
switch (ret) {
case 0:
printf("Image resized.\n");
break;
case -ENOTSUP:
error_report("This image format does not support resize");
break;
case -EACCES:
error_report("Image is read-only");
break;
default:
error_report("Error resizing image (%d)", -ret);
break;
}
out:
if (bs) {
bdrv_delete(bs);
}
if (ret) {
return 1;
}
return 0;
}
static const img_cmd_t img_cmds[] = {
#define DEF(option, callback, arg_string) \
{ option, callback },
#include "qemu-img-cmds.h"
#undef DEF
#undef GEN_DOCS
{ NULL, NULL, },
};
int main(int argc, char **argv)
{
const img_cmd_t *cmd;
const char *cmdname;
error_set_progname(argv[0]);
bdrv_init();
if (argc < 2)
help();
cmdname = argv[1];
argc--; argv++;
/* find the command */
for(cmd = img_cmds; cmd->name != NULL; cmd++) {
if (!strcmp(cmdname, cmd->name)) {
return cmd->handler(argc, argv);
}
}
/* not found */
help();
return 0;
}
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