From: Eric Blake <ebl...@redhat.com> Commit a290f085 exposed a latent bug in qemu-img map introduced during the conversion of block status to be byte-based. Earlier in commit 5e344dd8, the internal interface get_block_status() switched to take byte-based parameters, but still called a sector-based block layer function; as such, rounding was added in the lone caller to obey the contract. However, commit 237d78f8 changed get_block_status() to truly be byte-based, at which point rounding to sector boundaries can result in calling bdrv_block_status() with 'bytes == 0' (a coding error) when the boundary between data and a hole falls mid-sector (true for the past-EOF implicit hole present in POSIX files). Fix things by removing the rounding that is now no longer necessary.
See also https://bugzilla.redhat.com/1589738 Fixes: 237d78f8 Reported-by: Dan Kenigsberg <dan...@redhat.com> Reported-by: Nir Soffer <nsof...@redhat.com> Reported-by: Maor Lipchuk <mlipc...@redhat.com> CC: qemu-sta...@nongnu.org Signed-off-by: Eric Blake <ebl...@redhat.com> Signed-off-by: Kevin Wolf <kw...@redhat.com> (cherry picked from commit e0b371ed5e2db079051139136fd0478728b6a58f) Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com> --- qemu-img.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/qemu-img.c b/qemu-img.c index 86060aab71..bf9de27893 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -2826,7 +2826,7 @@ static int img_map(int argc, char **argv) int64_t n; /* Probe up to 1 GiB at a time. */ - n = QEMU_ALIGN_DOWN(MIN(1 << 30, length - offset), BDRV_SECTOR_SIZE); + n = MIN(1 << 30, length - offset); ret = get_block_status(bs, offset, n, &next); if (ret < 0) { -- 2.11.0
