vpc: fix return value check for blk_pwrite
commit40a99aace3f9ffd65af07a89c381db3550b22316
authorPaolo Bonzini <pbonzini@redhat.com>
Thu, 7 Apr 2016 14:52:34 +0000 (7 16:52 +0200)
committerKevin Wolf <kwolf@redhat.com>
Tue, 12 Apr 2016 16:06:51 +0000 (12 18:06 +0200)
treee2a235bc1d95ac54913fac51dcd32d892d53c7ea
parent1fd06db03da73db868e54b838bb5ea02c10eea6c
vpc: fix return value check for blk_pwrite

bdrv_pwrite_sync used to return zero or negative error, while blk_pwrite returns
the number of written bytes when successful.  This caused VPC image creation
to fail spectacularly: it wrote the first 512 bytes, and then exited immediately
because of the non-zero answer from blk_pwrite.  But the truly spectacular part
is that it returns a positive value (the 512 that blk_pwrite returned) causing
everyone to believe that it succeeded.

This fixes qemu-iotests with vpc format.

Fixes: b8f45cdf7827e39f9a1e6cc446f5972cc6144237
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/vpc.c