Commit 31826642 authored by Eric Blake's avatar Eric Blake Committed by Kevin Wolf
Browse files

block: Convert bdrv_get_block_status_above() to bytes 



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 name of the function from bdrv_get_block_status_above()
to bdrv_block_status_above() ensures that the compiler enforces that
all callers are updated.  Likewise, since it a byte interface allows
an offset mapping that might not be sector aligned, split the mapping
out of the return value and into a pass-by-reference parameter.  For
now, the io.c layer still assert()s that all uses are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status in the drivers.

For the most part this patch is just the addition of scaling at the
callers followed by inverse scaling at bdrv_block_status(), plus
updates for the new split return interface.  But some code,
particularly bdrv_block_status(), gets a lot simpler because it no
longer has to mess with sectors.  Likewise, mirror code no longer
computes s->granularity >> BDRV_SECTOR_BITS, and can therefore drop
an assertion about alignment because the loop no longer depends on
alignment (never mind that we don't really have a driver that
reports sub-sector alignments, so it's not really possible to test
the effect of sub-sector mirroring).  Fix a neighboring assertion to
use is_power_of_2 while there.

For ease of review, bdrv_get_block_status() was tackled separately.

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 5b648c67

block/io.c

+8 −47
Original line number Diff line number Diff line
@@ -2016,7 +2016,7 @@ static int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs, 
    return ret;

}



/* Coroutine wrapper for bdrv_get_block_status_above() */

/* Coroutine wrapper for bdrv_block_status_above() */

static void coroutine_fn bdrv_block_status_above_co_entry(void *opaque)

{

    BdrvCoBlockStatusData *data = opaque;
@@ -2064,58 +2064,19 @@ static int bdrv_common_block_status_above(BlockDriverState *bs, 
    return data.ret;

}



int64_t bdrv_get_block_status_above(BlockDriverState *bs,

                                    BlockDriverState *base,

                                    int64_t sector_num,

                                    int nb_sectors, int *pnum,

                                    BlockDriverState **file)

int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,

                            int64_t offset, int64_t bytes, int64_t *pnum,

                            int64_t *map, BlockDriverState **file)

{

    int64_t ret;

    int64_t n;

    int64_t map;



    ret = bdrv_common_block_status_above(bs, base, true,

                                         sector_num * BDRV_SECTOR_SIZE,

                                         nb_sectors * BDRV_SECTOR_SIZE,

                                         &n, &map, file);

    if (ret < 0) {

        *pnum = 0;

        return ret;

    }

    assert(QEMU_IS_ALIGNED(n | map, BDRV_SECTOR_SIZE));

    *pnum = n >> BDRV_SECTOR_BITS;

    return ret | map;

    return bdrv_common_block_status_above(bs, base, true, offset, bytes,

                                          pnum, map, file);

}



int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,

                      int64_t *pnum, int64_t *map, BlockDriverState **file)

{

    int64_t ret;

    int n;



    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));

    assert(pnum);

    /*

     * The contract allows us to return pnum smaller than bytes, even

     * if the next query would see the same status; we truncate the

     * request to avoid overflowing the driver's 32-bit interface.

     */

    bytes = MIN(bytes, BDRV_REQUEST_MAX_BYTES);

    ret = bdrv_get_block_status_above(bs, backing_bs(bs),

                                      offset >> BDRV_SECTOR_BITS,

                                      bytes >> BDRV_SECTOR_BITS, &n, file);

    if (ret < 0) {

        assert(INT_MIN <= ret);

        *pnum = 0;

        return ret;

    }

    *pnum = n * BDRV_SECTOR_SIZE;

    if (map) {

        *map = ret & BDRV_BLOCK_OFFSET_MASK;

    } else {

        ret &= ~BDRV_BLOCK_OFFSET_VALID;

    }

    return ret & ~BDRV_BLOCK_OFFSET_MASK;

    return bdrv_block_status_above(bs, backing_bs(bs),

                                   offset, bytes, pnum, map, file);

}



int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,

block/mirror.c

+6 −12
Original line number Diff line number Diff line
@@ -328,7 +328,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 
    uint64_t delay_ns = 0;

    /* At least the first dirty chunk is mirrored in one iteration. */

    int nb_chunks = 1;

    int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;

    bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));

    int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
@@ -376,7 +375,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 
    }



    /* Clear dirty bits before querying the block status, because

     * calling bdrv_get_block_status_above could yield - if some blocks are

     * calling bdrv_block_status_above could yield - if some blocks are

     * marked dirty in this window, we need to know.

     */

    bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
@@ -385,8 +384,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 


    bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);

    while (nb_chunks > 0 && offset < s->bdev_length) {

        int64_t ret;

        int io_sectors;

        int ret;

        int64_t io_bytes;

        int64_t io_bytes_acct;

        enum MirrorMethod {
@@ -396,11 +394,9 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 
        } mirror_method = MIRROR_METHOD_COPY;



        assert(!(offset % s->granularity));

        ret = bdrv_get_block_status_above(source, NULL,

                                          offset >> BDRV_SECTOR_BITS,

                                          nb_chunks * sectors_per_chunk,

                                          &io_sectors, NULL);

        io_bytes = io_sectors * BDRV_SECTOR_SIZE;

        ret = bdrv_block_status_above(source, NULL, offset,

                                      nb_chunks * s->granularity,

                                      &io_bytes, NULL, NULL);

        if (ret < 0) {

            io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);

        } else if (ret & BDRV_BLOCK_DATA) {
@@ -1131,9 +1127,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, 
        granularity = bdrv_get_default_bitmap_granularity(target);

    }



    assert ((granularity & (granularity - 1)) == 0);

    /* Granularity must be large enough for sector-based dirty bitmap */

    assert(granularity >= BDRV_SECTOR_SIZE);

    assert(is_power_of_2(granularity));



    if (buf_size < 0) {

        error_setg(errp, "Invalid parameter 'buf-size'");

block/qcow2.c

+12 −18
Original line number Diff line number Diff line
@@ -2974,8 +2974,8 @@ finish: 


static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)

{

    int nr;

    int64_t res;

    int64_t nr;

    int res;

    int64_t start;



    /* TODO: Widening to sector boundaries should only be needed as
@@ -2991,10 +2991,8 @@ static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 
    if (!bytes) {

        return true;

    }

    res = bdrv_get_block_status_above(bs, NULL, start >> BDRV_SECTOR_BITS,

                                      bytes >> BDRV_SECTOR_BITS, &nr, NULL);

    return res >= 0 && (res & BDRV_BLOCK_ZERO) &&

        nr * BDRV_SECTOR_SIZE == bytes;

    res = bdrv_block_status_above(bs, NULL, start, bytes, &nr, NULL, NULL);

    return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;

}



static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
@@ -3700,17 +3698,14 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 
            required = virtual_size;

        } else {

            int64_t offset;

            int pnum = 0;

            int64_t pnum = 0;



            for (offset = 0; offset < ssize;

                 offset += pnum * BDRV_SECTOR_SIZE) {

                int nb_sectors = MIN(ssize - offset,

                                     BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE;

                int64_t ret;

            for (offset = 0; offset < ssize; offset += pnum) {

                int ret;



                ret = bdrv_get_block_status_above(in_bs, NULL,

                                                  offset >> BDRV_SECTOR_BITS,

                                                  nb_sectors, &pnum, NULL);

                ret = bdrv_block_status_above(in_bs, NULL, offset,

                                              ssize - offset, &pnum, NULL,

                                              NULL);

                if (ret < 0) {

                    error_setg_errno(&local_err, -ret,

                                     "Unable to get block status");
@@ -3722,11 +3717,10 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 
                } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==

                           (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {

                    /* Extend pnum to end of cluster for next iteration */

                    pnum = (ROUND_UP(offset + pnum * BDRV_SECTOR_SIZE,

                                 cluster_size) - offset) >> BDRV_SECTOR_BITS;

                    pnum = ROUND_UP(offset + pnum, cluster_size) - offset;



                    /* Count clusters we've seen */

                    required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE;

                    required += offset % cluster_size + pnum;

                }

            }

        }

include/block/block.h

+3 −5
Original line number Diff line number Diff line
@@ -425,11 +425,9 @@ bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs); 
int bdrv_block_status(BlockDriverState *bs, int64_t offset,

                      int64_t bytes, int64_t *pnum, int64_t *map,

                      BlockDriverState **file);

int64_t bdrv_get_block_status_above(BlockDriverState *bs,

                                    BlockDriverState *base,

                                    int64_t sector_num,

                                    int nb_sectors, int *pnum,

                                    BlockDriverState **file);

int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,

                            int64_t offset, int64_t bytes, int64_t *pnum,

                            int64_t *map, BlockDriverState **file);

int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,

                      int64_t *pnum);

int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,

qemu-img.c

+28 −21
Original line number Diff line number Diff line
@@ -1226,7 +1226,7 @@ static int img_compare(int argc, char **argv) 
    BlockDriverState *bs1, *bs2;

    int64_t total_sectors1, total_sectors2;

    uint8_t *buf1 = NULL, *buf2 = NULL;

    int pnum1, pnum2;

    int64_t pnum1, pnum2;

    int allocated1, allocated2;

    int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */

    bool progress = false, quiet = false, strict = false;
@@ -1374,15 +1374,17 @@ static int img_compare(int argc, char **argv) 
    }



    for (;;) {

        int64_t status1, status2;

        int status1, status2;



        nb_sectors = sectors_to_process(total_sectors, sector_num);

        if (nb_sectors <= 0) {

            break;

        }

        status1 = bdrv_get_block_status_above(bs1, NULL, sector_num,

                                              total_sectors1 - sector_num,

                                              &pnum1, NULL);

        status1 = bdrv_block_status_above(bs1, NULL,

                                          sector_num * BDRV_SECTOR_SIZE,

                                          (total_sectors1 - sector_num) *

                                          BDRV_SECTOR_SIZE,

                                          &pnum1, NULL, NULL);

        if (status1 < 0) {

            ret = 3;

            error_report("Sector allocation test failed for %s", filename1);
@@ -1390,25 +1392,29 @@ static int img_compare(int argc, char **argv) 
        }

        allocated1 = status1 & BDRV_BLOCK_ALLOCATED;



        status2 = bdrv_get_block_status_above(bs2, NULL, sector_num,

                                              total_sectors2 - sector_num,

                                              &pnum2, NULL);

        status2 = bdrv_block_status_above(bs2, NULL,

                                          sector_num * BDRV_SECTOR_SIZE,

                                          (total_sectors2 - sector_num) *

                                          BDRV_SECTOR_SIZE,

                                          &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));

        if (pnum1) {

            nb_sectors = MIN(nb_sectors, pnum1);

            nb_sectors = MIN(nb_sectors, pnum1 >> BDRV_SECTOR_BITS);

        }

        if (pnum2) {

            nb_sectors = MIN(nb_sectors, pnum2);

            nb_sectors = MIN(nb_sectors, pnum2 >> BDRV_SECTOR_BITS);

        }



        if (strict) {

            if ((status1 & ~BDRV_BLOCK_OFFSET_MASK) !=

                (status2 & ~BDRV_BLOCK_OFFSET_MASK)) {

            if (status1 != status2) {

                ret = 1;

                qprintf(quiet, "Strict mode: Offset %" PRId64

                        " block status mismatch!\n",
@@ -1417,7 +1423,7 @@ static int img_compare(int argc, char **argv) 
            }

        }

        if ((status1 & BDRV_BLOCK_ZERO) && (status2 & BDRV_BLOCK_ZERO)) {

            nb_sectors = MIN(pnum1, pnum2);

            nb_sectors = DIV_ROUND_UP(MIN(pnum1, pnum2), BDRV_SECTOR_SIZE);

        } else if (allocated1 == allocated2) {

            if (allocated1) {

                ret = blk_pread(blk1, sector_num << BDRV_SECTOR_BITS, buf1,
@@ -1589,8 +1595,8 @@ static void convert_select_part(ImgConvertState *s, int64_t sector_num, 


static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)

{

    int64_t ret, src_cur_offset;

    int n, src_cur;

    int64_t src_cur_offset;

    int ret, n, src_cur;



    convert_select_part(s, sector_num, &src_cur, &src_cur_offset);
@@ -1598,23 +1604,24 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) 
    n = MIN(s->total_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);



    if (s->sector_next_status <= sector_num) {

        if (s->target_has_backing) {

        int64_t count = n * BDRV_SECTOR_SIZE;



        if (s->target_has_backing) {



            ret = bdrv_block_status(blk_bs(s->src[src_cur]),

                                    (sector_num - src_cur_offset) *

                                    BDRV_SECTOR_SIZE,

                                    count, &count, NULL, NULL);

            assert(ret < 0 || QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));

            n = count >> BDRV_SECTOR_BITS;

        } else {

            ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,

                                              sector_num - src_cur_offset,

                                              n, &n, NULL);

            ret = bdrv_block_status_above(blk_bs(s->src[src_cur]), NULL,

                                          (sector_num - src_cur_offset) *

                                          BDRV_SECTOR_SIZE,

                                          count, &count, NULL, NULL);

        }

        if (ret < 0) {

            return ret;

        }

        n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);



        if (ret & BDRV_BLOCK_ZERO) {

            s->status = BLK_ZERO;