From 51b0a488882328f8f02519bb47ca7e0e7fbe12ff Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 7 Jul 2017 07:44:59 -0500 Subject: [PATCH] block: Make bdrv_is_allocated_above() 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, but that can be relaxed when a later patch implements byte-based block status. Therefore, 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 stream_run(), gets a lot simpler because it no longer has to mess with sectors. Leave comments where we can further simplify by switching to byte-based iterations, once later patches eliminate the need for sector-aligned operations. For ease of review, bdrv_is_allocated() was tackled separately. Signed-off-by: Eric Blake Signed-off-by: Kevin Wolf --- block/commit.c | 20 ++++++++------------ block/io.c | 38 ++++++++++++++++++-------------------- block/mirror.c | 8 +++++++- block/replication.c | 17 ++++++++++++----- block/stream.c | 23 +++++++++-------------- include/block/block.h | 2 +- qemu-img.c | 13 ++++++++++--- 7 files changed, 65 insertions(+), 56 deletions(-) diff --git a/block/commit.c b/block/commit.c index 241aa95b3f..774a8a599c 100644 --- a/block/commit.c +++ b/block/commit.c @@ -146,7 +146,7 @@ static void coroutine_fn commit_run(void *opaque) int64_t offset; uint64_t delay_ns = 0; int ret = 0; - int n = 0; /* sectors */ + int64_t n = 0; /* bytes */ void *buf = NULL; int bytes_written = 0; int64_t base_len; @@ -171,7 +171,7 @@ static void coroutine_fn commit_run(void *opaque) buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE); - for (offset = 0; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) { + for (offset = 0; offset < s->common.len; offset += n) { bool copy; /* Note that even when no rate limit is applied we need to yield @@ -183,15 +183,12 @@ static void coroutine_fn commit_run(void *opaque) } /* Copy if allocated above the base */ ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), - offset / BDRV_SECTOR_SIZE, - COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE, - &n); + offset, COMMIT_BUFFER_SIZE, &n); copy = (ret == 1); - trace_commit_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret); + trace_commit_one_iteration(s, offset, n, ret); if (copy) { - ret = commit_populate(s->top, s->base, offset, - n * BDRV_SECTOR_SIZE, buf); - bytes_written += n * BDRV_SECTOR_SIZE; + ret = commit_populate(s->top, s->base, offset, n, buf); + bytes_written += n; } if (ret < 0) { BlockErrorAction action = @@ -204,11 +201,10 @@ static void coroutine_fn commit_run(void *opaque) } } /* Publish progress */ - s->common.offset += n * BDRV_SECTOR_SIZE; + s->common.offset += n; if (copy && s->common.speed) { - delay_ns = ratelimit_calculate_delay(&s->limit, - n * BDRV_SECTOR_SIZE); + delay_ns = ratelimit_calculate_delay(&s->limit, n); } } diff --git a/block/io.c b/block/io.c index aad7fd30a4..23170a57ee 100644 --- a/block/io.c +++ b/block/io.c @@ -1926,50 +1926,48 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset, /* * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] * - * Return true if the given sector is allocated in any image between - * BASE and TOP (inclusive). BASE can be NULL to check if the given - * sector is allocated in any image of the chain. Return false otherwise, + * Return true if (a prefix of) the given range is allocated in any image + * between BASE and TOP (inclusive). BASE can be NULL to check if the given + * offset is allocated in any image of the chain. Return false otherwise, * or negative errno on failure. * - * 'pnum' is set to the number of sectors (including and immediately following - * the specified sector) that are known to be in the same - * allocated/unallocated state. + * 'pnum' is set to the number of bytes (including and immediately + * following the specified offset) that are known to be in the same + * allocated/unallocated state. Note that a subsequent call starting + * at 'offset + *pnum' may return the same allocation status (in other + * words, the result is not necessarily the maximum possible range); + * but 'pnum' will only be 0 when end of file is reached. * */ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, - int64_t sector_num, - int nb_sectors, int *pnum) + int64_t offset, int64_t bytes, int64_t *pnum) { BlockDriverState *intermediate; - int ret, n = nb_sectors; + int ret; + int64_t n = bytes; intermediate = top; while (intermediate && intermediate != base) { int64_t pnum_inter; int64_t size_inter; - int psectors_inter; - ret = bdrv_is_allocated(intermediate, sector_num * BDRV_SECTOR_SIZE, - nb_sectors * BDRV_SECTOR_SIZE, - &pnum_inter); + ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter); if (ret < 0) { return ret; } - assert(pnum_inter < INT_MAX * BDRV_SECTOR_SIZE); - psectors_inter = pnum_inter >> BDRV_SECTOR_BITS; if (ret) { - *pnum = psectors_inter; + *pnum = pnum_inter; return 1; } - size_inter = bdrv_nb_sectors(intermediate); + size_inter = bdrv_getlength(intermediate); if (size_inter < 0) { return size_inter; } - if (n > psectors_inter && - (intermediate == top || sector_num + psectors_inter < size_inter)) { - n = psectors_inter; + if (n > pnum_inter && + (intermediate == top || offset + pnum_inter < size_inter)) { + n = pnum_inter; } intermediate = backing_bs(intermediate); diff --git a/block/mirror.c b/block/mirror.c index b33f4bb1d6..eaf0fe7858 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -621,6 +621,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) BlockDriverState *bs = s->source; BlockDriverState *target_bs = blk_bs(s->target); int ret, n; + int64_t count; end = s->bdev_length / BDRV_SECTOR_SIZE; @@ -670,11 +671,16 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) return 0; } - ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); + ret = bdrv_is_allocated_above(bs, base, sector_num * BDRV_SECTOR_SIZE, + nb_sectors * BDRV_SECTOR_SIZE, &count); if (ret < 0) { return ret; } + /* TODO: Relax this once bdrv_is_allocated_above and dirty + * bitmaps no longer require sector alignment. */ + assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)); + n = count >> BDRV_SECTOR_BITS; assert(n > 0); if (ret == 1) { bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); diff --git a/block/replication.c b/block/replication.c index 8f3aba7a20..bf4462c8e7 100644 --- a/block/replication.c +++ b/block/replication.c @@ -264,7 +264,8 @@ static coroutine_fn int replication_co_writev(BlockDriverState *bs, BdrvChild *top = bs->file; BdrvChild *base = s->secondary_disk; BdrvChild *target; - int ret, n; + int ret; + int64_t n; ret = replication_get_io_status(s); if (ret < 0) { @@ -283,14 +284,20 @@ static coroutine_fn int replication_co_writev(BlockDriverState *bs, */ qemu_iovec_init(&hd_qiov, qiov->niov); while (remaining_sectors > 0) { - ret = bdrv_is_allocated_above(top->bs, base->bs, sector_num, - remaining_sectors, &n); + int64_t count; + + ret = bdrv_is_allocated_above(top->bs, base->bs, + sector_num * BDRV_SECTOR_SIZE, + remaining_sectors * BDRV_SECTOR_SIZE, + &count); if (ret < 0) { goto out1; } + assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)); + n = count >> BDRV_SECTOR_BITS; qemu_iovec_reset(&hd_qiov); - qemu_iovec_concat(&hd_qiov, qiov, bytes_done, n * BDRV_SECTOR_SIZE); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count); target = ret ? top : base; ret = bdrv_co_writev(target, sector_num, n, &hd_qiov); @@ -300,7 +307,7 @@ static coroutine_fn int replication_co_writev(BlockDriverState *bs, remaining_sectors -= n; sector_num += n; - bytes_done += n * BDRV_SECTOR_SIZE; + bytes_done += count; } out1: diff --git a/block/stream.c b/block/stream.c index df9679c0fc..e6f72346e5 100644 --- a/block/stream.c +++ b/block/stream.c @@ -111,7 +111,7 @@ static void coroutine_fn stream_run(void *opaque) uint64_t delay_ns = 0; int error = 0; int ret = 0; - int n = 0; /* sectors */ + int64_t n = 0; /* bytes */ void *buf; if (!bs->backing) { @@ -135,9 +135,8 @@ static void coroutine_fn stream_run(void *opaque) bdrv_enable_copy_on_read(bs); } - for ( ; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) { + for ( ; offset < s->common.len; offset += n) { bool copy; - int64_t count = 0; /* Note that even when no rate limit is applied we need to yield * with no pending I/O here so that bdrv_drain_all() returns. @@ -149,28 +148,25 @@ static void coroutine_fn stream_run(void *opaque) copy = false; - ret = bdrv_is_allocated(bs, offset, STREAM_BUFFER_SIZE, &count); - /* TODO relax this once bdrv_is_allocated does not enforce sectors */ - assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)); - n = count >> BDRV_SECTOR_BITS; + ret = bdrv_is_allocated(bs, offset, STREAM_BUFFER_SIZE, &n); if (ret == 1) { /* Allocated in the top, no need to copy. */ } else if (ret >= 0) { /* Copy if allocated in the intermediate images. Limit to the * known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */ ret = bdrv_is_allocated_above(backing_bs(bs), base, - offset / BDRV_SECTOR_SIZE, n, &n); + offset, n, &n); /* Finish early if end of backing file has been reached */ if (ret == 0 && n == 0) { - n = (s->common.len - offset) / BDRV_SECTOR_SIZE; + n = s->common.len - offset; } copy = (ret == 1); } - trace_stream_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret); + trace_stream_one_iteration(s, offset, n, ret); if (copy) { - ret = stream_populate(blk, offset, n * BDRV_SECTOR_SIZE, buf); + ret = stream_populate(blk, offset, n, buf); } if (ret < 0) { BlockErrorAction action = @@ -189,10 +185,9 @@ static void coroutine_fn stream_run(void *opaque) ret = 0; /* Publish progress */ - s->common.offset += n * BDRV_SECTOR_SIZE; + s->common.offset += n; if (copy && s->common.speed) { - delay_ns = ratelimit_calculate_delay(&s->limit, - n * BDRV_SECTOR_SIZE); + delay_ns = ratelimit_calculate_delay(&s->limit, n); } } diff --git a/include/block/block.h b/include/block/block.h index 8d16cc1d98..4a2725267d 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -430,7 +430,7 @@ int64_t bdrv_get_block_status_above(BlockDriverState *bs, int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, int64_t *pnum); int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, - int64_t sector_num, int nb_sectors, int *pnum); + int64_t offset, int64_t bytes, int64_t *pnum); bool bdrv_is_read_only(BlockDriverState *bs); bool bdrv_is_writable(BlockDriverState *bs); diff --git a/qemu-img.c b/qemu-img.c index 86e24335fc..f7ffb79db6 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1508,12 +1508,16 @@ static int img_compare(int argc, char **argv) } for (;;) { + int64_t count; + nb_sectors = sectors_to_process(total_sectors_over, sector_num); if (nb_sectors <= 0) { break; } - ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL, sector_num, - nb_sectors, &pnum); + ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL, + sector_num * BDRV_SECTOR_SIZE, + nb_sectors * BDRV_SECTOR_SIZE, + &count); if (ret < 0) { ret = 3; error_report("Sector allocation test failed for %s", @@ -1521,7 +1525,10 @@ static int img_compare(int argc, char **argv) goto out; } - nb_sectors = pnum; + /* TODO relax this once bdrv_is_allocated_above does not enforce + * sector alignment */ + assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)); + nb_sectors = count >> BDRV_SECTOR_BITS; if (ret) { ret = check_empty_sectors(blk_over, sector_num, nb_sectors, filename_over, buf1, quiet);