aboutsummaryrefslogtreecommitdiff
path: root/qemu-img.c
diff options
context:
space:
mode:
Diffstat (limited to 'qemu-img.c')
-rw-r--r--qemu-img.c116
1 files changed, 78 insertions, 38 deletions
diff --git a/qemu-img.c b/qemu-img.c
index 95f3219571..6a3973163f 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -66,7 +66,8 @@ static void help(void)
" '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"
+ " options are: 'none', 'writeback' (default), 'writethrough', 'directsync'\n"
+ " 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"
@@ -81,6 +82,8 @@ static void help(void)
" 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"
+ " '-S' indicates the consecutive number of bytes that must contain only zeros\n"
+ " for qemu-img to create a sparse image during conversion\n"
"\n"
"Parameters to snapshot subcommand:\n"
" 'snapshot' is the name of the snapshot to create, apply or delete\n"
@@ -183,27 +186,6 @@ static int read_password(char *buf, int buf_size)
}
#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;
@@ -495,7 +477,7 @@ static int img_commit(int argc, char **argv)
filename = argv[optind++];
flags = BDRV_O_RDWR;
- ret = set_cache_flag(cache, &flags);
+ ret = bdrv_parse_cache_flags(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
return -1;
@@ -591,6 +573,48 @@ static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
}
/*
+ * Like is_allocated_sectors, but if the buffer starts with a used sector,
+ * up to 'min' consecutive sectors containing zeros are ignored. This avoids
+ * breaking up write requests for only small sparse areas.
+ */
+static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum,
+ int min)
+{
+ int ret;
+ int num_checked, num_used;
+
+ if (n < min) {
+ min = n;
+ }
+
+ ret = is_allocated_sectors(buf, n, pnum);
+ if (!ret) {
+ return ret;
+ }
+
+ num_used = *pnum;
+ buf += BDRV_SECTOR_SIZE * *pnum;
+ n -= *pnum;
+ num_checked = num_used;
+
+ while (n > 0) {
+ ret = is_allocated_sectors(buf, n, pnum);
+
+ buf += BDRV_SECTOR_SIZE * *pnum;
+ n -= *pnum;
+ num_checked += *pnum;
+ if (ret) {
+ num_used = num_checked;
+ } else if (*pnum >= min) {
+ break;
+ }
+ }
+
+ *pnum = num_used;
+ return 1;
+}
+
+/*
* Compares two buffers sector by sector. Returns 0 if the first sector of both
* buffers matches, non-zero otherwise.
*
@@ -640,6 +664,7 @@ static int img_convert(int argc, char **argv)
char *options = NULL;
const char *snapshot_name = NULL;
float local_progress;
+ int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */
fmt = NULL;
out_fmt = "raw";
@@ -647,7 +672,7 @@ static int img_convert(int argc, char **argv)
out_baseimg = NULL;
compress = 0;
for(;;) {
- c = getopt(argc, argv, "f:O:B:s:hce6o:pt:");
+ c = getopt(argc, argv, "f:O:B:s:hce6o:pS:t:");
if (c == -1) {
break;
}
@@ -682,6 +707,18 @@ static int img_convert(int argc, char **argv)
case 's':
snapshot_name = optarg;
break;
+ case 'S':
+ {
+ int64_t sval;
+ sval = strtosz_suffix(optarg, NULL, STRTOSZ_DEFSUFFIX_B);
+ if (sval < 0) {
+ error_report("Invalid minimum zero buffer size for sparse output specified");
+ return 1;
+ }
+
+ min_sparse = sval / BDRV_SECTOR_SIZE;
+ break;
+ }
case 'p':
progress = 1;
break;
@@ -819,7 +856,7 @@ static int img_convert(int argc, char **argv)
}
flags = BDRV_O_RDWR;
- ret = set_cache_flag(cache, &flags);
+ ret = bdrv_parse_cache_flags(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
return -1;
@@ -834,7 +871,7 @@ static int img_convert(int argc, char **argv)
bs_i = 0;
bs_offset = 0;
bdrv_get_geometry(bs[0], &bs_sectors);
- buf = g_malloc(IO_BUF_SIZE);
+ buf = qemu_blockalign(out_bs, IO_BUF_SIZE);
if (compress) {
ret = bdrv_get_info(out_bs, &bdi);
@@ -890,7 +927,8 @@ static int img_convert(int argc, char **argv)
ret = bdrv_read(bs[bs_i], bs_num, buf2, nlow);
if (ret < 0) {
- error_report("error while reading");
+ error_report("error while reading sector %" PRId64 ": %s",
+ bs_num, strerror(-ret));
goto out;
}
@@ -908,8 +946,8 @@ static int img_convert(int argc, char **argv)
ret = bdrv_write_compressed(out_bs, sector_num, buf,
cluster_sectors);
if (ret != 0) {
- error_report("error while compressing sector %" PRId64,
- sector_num);
+ error_report("error while compressing sector %" PRId64
+ ": %s", sector_num, strerror(-ret));
goto out;
}
}
@@ -972,7 +1010,8 @@ static int img_convert(int argc, char **argv)
ret = bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n);
if (ret < 0) {
- error_report("error while reading");
+ error_report("error while reading sector %" PRId64 ": %s",
+ sector_num - bs_offset, strerror(-ret));
goto out;
}
/* NOTE: at the same time we convert, we do not write zero
@@ -988,10 +1027,11 @@ static int img_convert(int argc, char **argv)
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)) {
+ is_allocated_sectors_min(buf1, n, &n1, min_sparse)) {
ret = bdrv_write(out_bs, sector_num, buf1, n1);
if (ret < 0) {
- error_report("error while writing");
+ error_report("error while writing sector %" PRId64
+ ": %s", sector_num, strerror(-ret));
goto out;
}
}
@@ -1006,7 +1046,7 @@ out:
qemu_progress_end();
free_option_parameters(create_options);
free_option_parameters(param);
- g_free(buf);
+ qemu_vfree(buf);
if (out_bs) {
bdrv_delete(out_bs);
}
@@ -1291,7 +1331,7 @@ static int img_rebase(int argc, char **argv)
qemu_progress_print(0, 100);
flags = BDRV_O_RDWR | (unsafe ? BDRV_O_NO_BACKING : 0);
- ret = set_cache_flag(cache, &flags);
+ ret = bdrv_parse_cache_flags(cache, &flags);
if (ret < 0) {
error_report("Invalid cache option: %s", cache);
return -1;
@@ -1373,8 +1413,8 @@ static int img_rebase(int argc, char **argv)
uint8_t * buf_new;
float local_progress;
- buf_old = g_malloc(IO_BUF_SIZE);
- buf_new = g_malloc(IO_BUF_SIZE);
+ buf_old = qemu_blockalign(bs, IO_BUF_SIZE);
+ buf_new = qemu_blockalign(bs, IO_BUF_SIZE);
bdrv_get_geometry(bs, &num_sectors);
@@ -1430,8 +1470,8 @@ static int img_rebase(int argc, char **argv)
qemu_progress_print(local_progress, 100);
}
- g_free(buf_old);
- g_free(buf_new);
+ qemu_vfree(buf_old);
+ qemu_vfree(buf_new);
}
/*
generated by cgit v1.2.3 (git 2.26.2) at 2025-01-04 12:28:26 +0000