Re: [libvirt] [PATCH 3/3] util: storage: Improve error message when requesting image above 'start'

On Tue, Apr 21, 2015 at 05:52:14PM +0200, Peter Krempa wrote: >When a user would specify a backing chain index that is above the start >point libvirt would report a rather unhelpful error: > >invalid argument: could not find backing store 1 in chain for 'sub/link2' > >This patch adds an explicit check that the index is below start point in >the backing store and reports the following error if not: > >invalid argument: requested backing store index 1 is above 'sub/../qcow2' in chain for 'sub/link2' > >Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1177062 >--- > src/util/virstoragefile.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > >diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c >index c9d3977..2a2f238 100644 >--- a/src/util/virstoragefile.c >+++ b/src/util/virstoragefile.c >@@ -1341,6 +1341,15 @@ virStorageFileChainLookup(virStorageSourcePtr chain, > *parent = startFrom; > } > >+ if (idx && idx < i) { >+ virReportError(VIR_ERR_INVALID_ARG, >+ _("requested backing store index %u is above '%s' " >+ "in chain for '%s'"), >+ idx, NULLSTR(startFrom->path), NULLSTR(start)); Possible crasher: startFrom can be NULL here, rather move the check into the previous block where the parent is being set when found (idx can't be < i when there is no startFrom anyway). You can then avoid cleaning up the *parent here -+ | +-----------+ | v