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author | Max Reitz <mreitz@redhat.com> | 2017-11-10 21:31:09 +0100 |
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committer | Max Reitz <mreitz@redhat.com> | 2017-11-17 18:21:31 +0100 |
commit | d470ad42acfc73c45d3e8ed5311a491160b4c100 (patch) | |
tree | cd64f938783d3c530c25f7d8c8d5de8735264fe0 /roms | |
parent | 93bbaf03ff7fd490e823814b8f5d6849a7b71a64 (diff) | |
download | qemu-d470ad42acfc73c45d3e8ed5311a491160b4c100.zip qemu-d470ad42acfc73c45d3e8ed5311a491160b4c100.tar.gz qemu-d470ad42acfc73c45d3e8ed5311a491160b4c100.tar.bz2 |
block: Guard against NULL bs->drv
We currently do not guard everywhere against a NULL bs->drv where we
should be doing so. Most of the places fixed here just do not care
about that case at all.
Some care implicitly, e.g. through a prior function call to
bdrv_getlength() which would always fail for an ejected BDS. Add an
assert there to make it more obvious.
Other places seem to care, but do so insufficiently: Freeing clusters in
a qcow2 image is an error-free operation, but it may leave the image in
an unusable state anyway. Giving qcow2_free_clusters() an error code is
not really viable, it is much easier to note that bs->drv may be NULL
even after a successful driver call. This concerns bdrv_co_flush(), and
the way the check is added to bdrv_co_pdiscard() (in every iteration
instead of only once).
Finally, some places employ at least an assert(bs->drv); somewhere, that
may be reasonable (such as in the reopen code), but in
bdrv_has_zero_init(), it is definitely not. Returning 0 there in case
of an ejected BDS saves us much headache instead.
Reported-by: R. Nageswara Sastry <nasastry@in.ibm.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1728660
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171110203111.7666-4-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'roms')
0 files changed, 0 insertions, 0 deletions