On 10/22/2014 09:57 AM, Max Reitz wrote:
As its comment states, raw_co_get_block_status() should unconditionally
return 0 and set *pnum to 0 for after EOF.
An assertion after lseek(..., SEEK_HOLE) tried to catch this case by
asserting that errno != -ENXIO (which would indicate a position after
the EOF); but it should be errno != ENXIO instead. Regardless of that,
there should be no such assertion at all. If bdrv_getlength() returned
an outdated value and the image has been resized outside of qemu,
lseek() will return with errno == ENXIO. Just return that value as an
error then.
Setting *pnum to 0 and returning 0 should not be done here, as in that
case we should update the device length as well. So, from qemu's
perspective, the file has not been resized; it's just that there was an
error querying sectors beyond a certain point (the actual file size).
Additionally, nb_sectors should be clamped against the image end. This
was probably not an issue if FIEMAP or SEEK_HOLE/SEEK_DATA worked, but
the fallback did not take this case into account.
Reported-by: Kevin Wolf <address@hidden>
Signed-off-by: Max Reitz <address@hidden>
---
block/raw-posix.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
Reviewed-by: Eric Blake <address@hidden>
+ if (total_size < 0) {
+ return total_size;
+ } else if (start >= total_size) {
+ *pnum = 0;
+ return 0;
+ } else if (start + nb_sectors * BDRV_SECTOR_SIZE > total_size) {
+ nb_sectors = (total_size - start) / BDRV_SECTOR_SIZE;
Should this round up instead of truncate? But it would only matter for
a file size that is not a multiple of sectors, where we probably have
other issues, and where reporting just the full sectors also seems
reasonable.