On 09/13/2017 12:03 PM, Eric Blake wrote:
> In the continuing quest to make more things byte-based, change
> the internal iteration of img_compare(). We can finally drop the
> TODO assertion 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 <ebl...@redhat.com>
>
> ---
> v3: new patch
> ---
> qemu-img.c | 119
> ++++++++++++++++++++++++-------------------------------------
> 1 file changed, 46 insertions(+), 73 deletions(-)
>
> diff --git a/qemu-img.c b/qemu-img.c
> index 028c34a2cc..ef7062649d 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -1185,11 +1185,6 @@ 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)
> *
> @@ -1240,7 +1235,7 @@ 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;
> @@ -1248,9 +1243,9 @@ 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;
> @@ -1364,39 +1359,36 @@ 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) {
> int64_t status1, status2;
>
> - status1 = bdrv_block_status_above(bs1, NULL,
> - sector_num * BDRV_SECTOR_SIZE,
> - (total_sectors1 - sector_num) *
> - BDRV_SECTOR_SIZE,
> - &pnum1, NULL);
> + status1 = bdrv_block_status_above(bs1, NULL, offset,
> + total_size1 - offset, &pnum1,
> NULL);
> if (status1 < 0) {
> ret = 3;
> error_report("Sector allocation test failed for %s", filename1);
> @@ -1404,11 +1396,8 @@ 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);
> + status2 = bdrv_block_status_above(bs2, NULL, offset,
> + total_size2 - offset, &pnum2,
> NULL);
> if (status2 < 0) {
> ret = 3;
> error_report("Sector allocation test failed for %s", filename2);
> @@ -1417,15 +1406,14 @@ static int img_compare(int argc, char **argv)
> allocated2 = status2 & BDRV_BLOCK_ALLOCATED;
>
> assert(pnum1 && pnum2);
> - nb_sectors = DIV_ROUND_UP(MIN(pnum1, pnum2), BDRV_SECTOR_SIZE);
> + chunk = MIN(pnum1, pnum2);
Ayup, there goes that line.
>
> if (strict) {
> if ((status1 & ~BDRV_BLOCK_OFFSET_MASK) !=
> (status2 & ~BDRV_BLOCK_OFFSET_MASK)) {
> ret = 1;
> qprintf(quiet, "Strict mode: Offset %" PRId64
> - " block status mismatch!\n",
> - sectors_to_bytes(sector_num));
> + " block status mismatch!\n", offset);
> goto out;
> }
> }
> @@ -1435,59 +1423,54 @@ 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);
> + 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),
> filename1,
> - strerror(-ret));
> + error_report("Error while reading offset %" PRId64
> + " of %s: %s",
> + offset, filename1, strerror(-ret));
> ret = 4;
> goto out;
> }
> - ret = blk_pread(blk2, sector_num << BDRV_SECTOR_BITS, buf2,
> - nb_sectors << BDRV_SECTOR_BITS);
> + ret = blk_pread(blk2, offset, buf2, 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, filename2, 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 = 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 {
> @@ -1495,14 +1478,10 @@ 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);
> + while (offset < progress_base) {
> + ret = bdrv_block_status_above(blk_bs(blk_over), NULL, offset,
> + progress_base - offset, &chunk,
> + NULL);
> if (ret < 0) {
> ret = 3;
> error_report("Sector allocation test failed for %s",
> @@ -1510,22 +1489,16 @@ 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);
> }
> }
>
Reviewed-by: John Snow <js...@redhat.com>
