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qemu-img: Change img_compare() to be byte-based

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In the continuing quest to make more things byte-based, change
the internal iteration of img_compare().  We can finally drop the
TODO assertions added earlier, now that the entire algorithm is
byte-based and no longer has to shift from bytes to sectors.

Most of the change is mechanical ('total_sectors' becomes
'total_size', 'sector_num' becomes 'offset', 'nb_sectors' becomes
'chunk', 'progress_base' goes from sectors to bytes); some of it
is also a cleanup (sectors_to_bytes() is now unused, loss of
variable 'count' added earlier in commit 51b0a488).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2017-10-11 22:47:16 -05:00 committed by Kevin Wolf
parent 415362873f
commit 033d9fc203
1 changed files with 52 additions and 80 deletions
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132
qemu-img.c
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@ -1186,11 +1186,6 @@ static int compare_buffers(const uint8_t *buf1, const uint8_t *buf2,
#define IO_BUF_SIZE (2 * 1024 * 1024)
static int64_t sectors_to_bytes(int64_t sectors)
{
return sectors << BDRV_SECTOR_BITS;
}
/*
* Check if passed sectors are empty (not allocated or contain only 0 bytes)
*
@ -1241,7 +1236,7 @@ static int img_compare(int argc, char **argv)
const char *fmt1 = NULL, *fmt2 = NULL, *cache, *filename1, *filename2;
BlockBackend *blk1, *blk2;
BlockDriverState *bs1, *bs2;
int64_t total_sectors1, total_sectors2;
int64_t total_size1, total_size2;
uint8_t *buf1 = NULL, *buf2 = NULL;
int64_t pnum1, pnum2;
int allocated1, allocated2;
@ -1249,9 +1244,9 @@ static int img_compare(int argc, char **argv)
bool progress = false, quiet = false, strict = false;
int flags;
bool writethrough;
int64_t total_sectors;
int64_t sector_num = 0;
int64_t nb_sectors;
int64_t total_size;
int64_t offset = 0;
int64_t chunk;
int c;
uint64_t progress_base;
bool image_opts = false;
@ -1365,39 +1360,37 @@ static int img_compare(int argc, char **argv)
buf1 = blk_blockalign(blk1, IO_BUF_SIZE);
buf2 = blk_blockalign(blk2, IO_BUF_SIZE);
total_sectors1 = blk_nb_sectors(blk1);
if (total_sectors1 < 0) {
total_size1 = blk_getlength(blk1);
if (total_size1 < 0) {
error_report("Can't get size of %s: %s",
filename1, strerror(-total_sectors1));
filename1, strerror(-total_size1));
ret = 4;
goto out;
}
total_sectors2 = blk_nb_sectors(blk2);
if (total_sectors2 < 0) {
total_size2 = blk_getlength(blk2);
if (total_size2 < 0) {
error_report("Can't get size of %s: %s",
filename2, strerror(-total_sectors2));
filename2, strerror(-total_size2));
ret = 4;
goto out;
}
total_sectors = MIN(total_sectors1, total_sectors2);
progress_base = MAX(total_sectors1, total_sectors2);
total_size = MIN(total_size1, total_size2);
progress_base = MAX(total_size1, total_size2);
qemu_progress_print(0, 100);
if (strict && total_sectors1 != total_sectors2) {
if (strict && total_size1 != total_size2) {
ret = 1;
qprintf(quiet, "Strict mode: Image size mismatch!\n");
goto out;
}
while (sector_num < total_sectors) {
while (offset < total_size) {
int status1, status2;
status1 = bdrv_block_status_above(bs1, NULL,
sector_num * BDRV_SECTOR_SIZE,
(total_sectors1 - sector_num) *
BDRV_SECTOR_SIZE,
&pnum1, NULL, NULL);
status1 = bdrv_block_status_above(bs1, NULL, offset,
total_size1 - offset, &pnum1, NULL,
NULL);
if (status1 < 0) {
ret = 3;
error_report("Sector allocation test failed for %s", filename1);
@ -1405,30 +1398,24 @@ static int img_compare(int argc, char **argv)
}
allocated1 = status1 & BDRV_BLOCK_ALLOCATED;
status2 = bdrv_block_status_above(bs2, NULL,
sector_num * BDRV_SECTOR_SIZE,
(total_sectors2 - sector_num) *
BDRV_SECTOR_SIZE,
&pnum2, NULL, NULL);
status2 = bdrv_block_status_above(bs2, NULL, offset,
total_size2 - offset, &pnum2, NULL,
NULL);
if (status2 < 0) {
ret = 3;
error_report("Sector allocation test failed for %s", filename2);
goto out;
}
allocated2 = status2 & BDRV_BLOCK_ALLOCATED;
/* TODO: Relax this once comparison is byte-based, and we no longer
* have to worry about sector alignment */
assert(QEMU_IS_ALIGNED(pnum1 | pnum2, BDRV_SECTOR_SIZE));
assert(pnum1 && pnum2);
nb_sectors = MIN(pnum1, pnum2) >> BDRV_SECTOR_BITS;
chunk = MIN(pnum1, pnum2);
if (strict) {
if (status1 != status2) {
ret = 1;
qprintf(quiet, "Strict mode: Offset %" PRId64
" block status mismatch!\n",
sectors_to_bytes(sector_num));
" block status mismatch!\n", offset);
goto out;
}
}
@ -1438,59 +1425,54 @@ static int img_compare(int argc, char **argv)
if (allocated1) {
int64_t pnum;
nb_sectors = MIN(nb_sectors, IO_BUF_SIZE >> BDRV_SECTOR_BITS);
ret = blk_pread(blk1, sector_num << BDRV_SECTOR_BITS, buf1,
nb_sectors << BDRV_SECTOR_BITS);
if (ret < 0) {
error_report("Error while reading offset %" PRId64 " of %s:"
" %s", sectors_to_bytes(sector_num), filename1,
strerror(-ret));
ret = 4;
goto out;
}
ret = blk_pread(blk2, sector_num << BDRV_SECTOR_BITS, buf2,
nb_sectors << BDRV_SECTOR_BITS);
chunk = MIN(chunk, IO_BUF_SIZE);
ret = blk_pread(blk1, offset, buf1, chunk);
if (ret < 0) {
error_report("Error while reading offset %" PRId64
" of %s: %s", sectors_to_bytes(sector_num),
filename2, strerror(-ret));
" of %s: %s",
offset, filename1, strerror(-ret));
ret = 4;
goto out;
}
ret = compare_buffers(buf1, buf2,
nb_sectors * BDRV_SECTOR_SIZE, &pnum);
if (ret || pnum != nb_sectors * BDRV_SECTOR_SIZE) {
ret = blk_pread(blk2, offset, buf2, chunk);
if (ret < 0) {
error_report("Error while reading offset %" PRId64
" of %s: %s",
offset, filename2, strerror(-ret));
ret = 4;
goto out;
}
ret = compare_buffers(buf1, buf2, chunk, &pnum);
if (ret || pnum != chunk) {
qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
sectors_to_bytes(sector_num) + (ret ? 0 : pnum));
offset + (ret ? 0 : pnum));
ret = 1;
goto out;
}
}
} else {
nb_sectors = MIN(nb_sectors, IO_BUF_SIZE >> BDRV_SECTOR_BITS);
chunk = MIN(chunk, IO_BUF_SIZE);
if (allocated1) {
ret = check_empty_sectors(blk1, sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
ret = check_empty_sectors(blk1, offset, chunk,
filename1, buf1, quiet);
} else {
ret = check_empty_sectors(blk2, sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
ret = check_empty_sectors(blk2, offset, chunk,
filename2, buf1, quiet);
}
if (ret) {
goto out;
}
}
sector_num += nb_sectors;
qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
offset += chunk;
qemu_progress_print(((float) chunk / progress_base) * 100, 100);
}
if (total_sectors1 != total_sectors2) {
if (total_size1 != total_size2) {
BlockBackend *blk_over;
const char *filename_over;
qprintf(quiet, "Warning: Image size mismatch!\n");
if (total_sectors1 > total_sectors2) {
if (total_size1 > total_size2) {
blk_over = blk1;
filename_over = filename1;
} else {
@ -1498,14 +1480,10 @@ static int img_compare(int argc, char **argv)
filename_over = filename2;
}
while (sector_num < progress_base) {
int64_t count;
ret = bdrv_block_status_above(blk_bs(blk_over), NULL,
sector_num * BDRV_SECTOR_SIZE,
(progress_base - sector_num) *
BDRV_SECTOR_SIZE,
&count, NULL, NULL);
while (offset < progress_base) {
ret = bdrv_block_status_above(blk_bs(blk_over), NULL, offset,
progress_base - offset, &chunk,
NULL, NULL);
if (ret < 0) {
ret = 3;
error_report("Sector allocation test failed for %s",
@ -1513,22 +1491,16 @@ static int img_compare(int argc, char **argv)
goto out;
}
/* TODO relax this once bdrv_block_status_above does not enforce
* sector alignment */
assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
nb_sectors = count >> BDRV_SECTOR_BITS;
if (ret & BDRV_BLOCK_ALLOCATED && !(ret & BDRV_BLOCK_ZERO)) {
nb_sectors = MIN(nb_sectors, IO_BUF_SIZE >> BDRV_SECTOR_BITS);
ret = check_empty_sectors(blk_over,
sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
chunk = MIN(chunk, IO_BUF_SIZE);
ret = check_empty_sectors(blk_over, offset, chunk,
filename_over, buf1, quiet);
if (ret) {
goto out;
}
}
sector_num += nb_sectors;
qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
offset += chunk;
qemu_progress_print(((float) chunk / progress_base) * 100, 100);
}
}