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/qemu/block/
H A Dfile-posix.ca290f085 Tue Feb 13 20:26:44 GMT 2018 Eric Blake <eblake@redhat.com> file-posix: Switch to .bdrv_co_block_status()

We are gradually moving away from sector-based interfaces, towards
byte-based. Update the file protocol driver accordingly.

In want_zero mode, we continue to report fine-grained hole
information (the caller wants as much mapping detail as possible);
but when not in that mode, the caller prefers larger *pnum and
merely cares about what offsets are allocated at this layer, rather
than where the holes live. Since holes still read as zeroes at
this layer (rather than deferring to a backing layer), we can take
the shortcut of skipping lseek(), and merely state that all bytes
are allocated.

We can also drop redundant bounds checks that are already
guaranteed by the block layer.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
/qemu/
H A Dqemu-img.ce0b371ed Mon Jun 11 21:39:26 GMT 2018 Eric Blake <eblake@redhat.com> qemu-img: Fix assert when mapping unaligned raw file

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 <danken@redhat.com>
Reported-by: Nir Soffer <nsoffer@redhat.com>
Reported-by: Maor Lipchuk <mlipchuk@redhat.com>
CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>