From d6a644bbfef81bb6c7ab11656ad71e326f75ac77 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 7 Jul 2017 07:44:57 -0500 Subject: block: Make bdrv_is_allocated() byte-based We are gradually moving away from sector-based interfaces, towards byte-based. In the common case, allocation is unlikely to ever use values that are not naturally sector-aligned, but it is possible that byte-based values will let us be more precise about allocation at the end of an unaligned file that can do byte-based access. Changing the signature of the function to use int64_t *pnum ensures that the compiler enforces that all callers are updated. For now, the io.c layer still assert()s that all callers are sector-aligned on input and that *pnum is sector-aligned on return to the caller, but that can be relaxed when a later patch implements byte-based block status. Therefore, this code adds usages like DIV_ROUND_UP(,BDRV_SECTOR_SIZE) to callers that still want aligned values, where the call might reasonbly give non-aligned results in the future; on the other hand, no rounding is needed for callers that should just continue to work with byte alignment. For the most part this patch is just the addition of scaling at the callers followed by inverse scaling at bdrv_is_allocated(). But some code, particularly bdrv_commit(), gets a lot simpler because it no longer has to mess with sectors; also, it is now possible to pass NULL if the caller does not care how much of the image is allocated beyond the initial offset. Leave comments where we can further simplify once a later patch eliminates the need for sector-aligned requests through bdrv_is_allocated(). For ease of review, bdrv_is_allocated_above() will be tackled separately. Signed-off-by: Eric Blake Signed-off-by: Kevin Wolf --- qemu-io-cmds.c | 70 +++++++++++++++++++++++++++------------------------------- 1 file changed, 32 insertions(+), 38 deletions(-) (limited to 'qemu-io-cmds.c') diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c index b0ea327024..f4fdf2dcce 100644 --- a/qemu-io-cmds.c +++ b/qemu-io-cmds.c @@ -1760,12 +1760,12 @@ out: static int alloc_f(BlockBackend *blk, int argc, char **argv) { BlockDriverState *bs = blk_bs(blk); - int64_t offset, sector_num, nb_sectors, remaining, count; + int64_t offset, start, remaining, count; char s1[64]; - int num, ret; - int64_t sum_alloc; + int ret; + int64_t num, sum_alloc; - offset = cvtnum(argv[1]); + start = offset = cvtnum(argv[1]); if (offset < 0) { print_cvtnum_err(offset, argv[1]); return 0; @@ -1793,32 +1793,30 @@ static int alloc_f(BlockBackend *blk, int argc, char **argv) count); return 0; } - nb_sectors = count >> BDRV_SECTOR_BITS; - remaining = nb_sectors; + remaining = count; sum_alloc = 0; - sector_num = offset >> 9; while (remaining) { - ret = bdrv_is_allocated(bs, sector_num, remaining, &num); + ret = bdrv_is_allocated(bs, offset, remaining, &num); if (ret < 0) { printf("is_allocated failed: %s\n", strerror(-ret)); return 0; } - sector_num += num; + offset += num; remaining -= num; if (ret) { sum_alloc += num; } if (num == 0) { - nb_sectors -= remaining; + count -= remaining; remaining = 0; } } - cvtstr(offset, s1, sizeof(s1)); + cvtstr(start, s1, sizeof(s1)); printf("%"PRId64"/%"PRId64" bytes allocated at offset %s\n", - sum_alloc << BDRV_SECTOR_BITS, nb_sectors << BDRV_SECTOR_BITS, s1); + sum_alloc, count, s1); return 0; } @@ -1833,14 +1831,15 @@ static const cmdinfo_t alloc_cmd = { }; -static int map_is_allocated(BlockDriverState *bs, int64_t sector_num, - int64_t nb_sectors, int64_t *pnum) +static int map_is_allocated(BlockDriverState *bs, int64_t offset, + int64_t bytes, int64_t *pnum) { - int num, num_checked; + int64_t num; + int num_checked; int ret, firstret; - num_checked = MIN(nb_sectors, INT_MAX); - ret = bdrv_is_allocated(bs, sector_num, num_checked, &num); + num_checked = MIN(bytes, BDRV_REQUEST_MAX_BYTES); + ret = bdrv_is_allocated(bs, offset, num_checked, &num); if (ret < 0) { return ret; } @@ -1848,12 +1847,12 @@ static int map_is_allocated(BlockDriverState *bs, int64_t sector_num, firstret = ret; *pnum = num; - while (nb_sectors > 0 && ret == firstret) { - sector_num += num; - nb_sectors -= num; + while (bytes > 0 && ret == firstret) { + offset += num; + bytes -= num; - num_checked = MIN(nb_sectors, INT_MAX); - ret = bdrv_is_allocated(bs, sector_num, num_checked, &num); + num_checked = MIN(bytes, BDRV_REQUEST_MAX_BYTES); + ret = bdrv_is_allocated(bs, offset, num_checked, &num); if (ret == firstret && num) { *pnum += num; } else { @@ -1866,25 +1865,21 @@ static int map_is_allocated(BlockDriverState *bs, int64_t sector_num, static int map_f(BlockBackend *blk, int argc, char **argv) { - int64_t offset; - int64_t nb_sectors, total_sectors; + int64_t offset, bytes; char s1[64], s2[64]; int64_t num; int ret; const char *retstr; offset = 0; - total_sectors = blk_nb_sectors(blk); - if (total_sectors < 0) { - error_report("Failed to query image length: %s", - strerror(-total_sectors)); + bytes = blk_getlength(blk); + if (bytes < 0) { + error_report("Failed to query image length: %s", strerror(-bytes)); return 0; } - nb_sectors = total_sectors; - - do { - ret = map_is_allocated(blk_bs(blk), offset, nb_sectors, &num); + while (bytes) { + ret = map_is_allocated(blk_bs(blk), offset, bytes, &num); if (ret < 0) { error_report("Failed to get allocation status: %s", strerror(-ret)); return 0; @@ -1894,15 +1889,14 @@ static int map_f(BlockBackend *blk, int argc, char **argv) } retstr = ret ? " allocated" : "not allocated"; - cvtstr(num << BDRV_SECTOR_BITS, s1, sizeof(s1)); - cvtstr(offset << BDRV_SECTOR_BITS, s2, sizeof(s2)); + cvtstr(num, s1, sizeof(s1)); + cvtstr(offset, s2, sizeof(s2)); printf("%s (0x%" PRIx64 ") bytes %s at offset %s (0x%" PRIx64 ")\n", - s1, num << BDRV_SECTOR_BITS, retstr, - s2, offset << BDRV_SECTOR_BITS); + s1, num, retstr, s2, offset); offset += num; - nb_sectors -= num; - } while (offset < total_sectors); + bytes -= num; + } return 0; } -- cgit v1.2.3