From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45121) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cWRbp-00064T-5j for qemu-devel@nongnu.org; Wed, 25 Jan 2017 12:43:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cWRbo-0006FL-8B for qemu-devel@nongnu.org; Wed, 25 Jan 2017 12:43:49 -0500 Date: Wed, 25 Jan 2017 12:43:40 -0500 From: Jeff Cody Message-ID: <20170125174340.GA2688@localhost.localdomain> References: <9a93d47ddba5f86d36cbdf884d86e2fa6f5542ae.1485364872.git.jcody@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9a93d47ddba5f86d36cbdf884d86e2fa6f5542ae.1485364872.git.jcody@redhat.com> Subject: Re: [Qemu-devel] [PATCH 1/1] block: check full backing filename when searching protocol filenames List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, mreitz@redhat.com, qemu-block@nongnu.org Forgot to cc qemu-block, added. On Wed, Jan 25, 2017 at 12:22:02PM -0500, Jeff Cody wrote: > In bdrv_find_backing_image(), if we are searching an image for a backing > file that contains a protocol, we currently only compare unmodified > paths. > > However, some management software will change the backing filename to be > a relative filename in a path. QEMU is able to handle this fine, > because internally it will use path_combine to put together the full > protocol URI. > > However, this can lead to an inability to match an image during a QAPI > command that needs to use bdrv_find_backing_image() to find the image, > when it is searched by the full URI. > > When searching for a protocol filename, if the straight comparison > fails, this patch will also compare against the full backing filename to > see if that is a match. > > Signed-off-by: Jeff Cody > --- > block.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/block.c b/block.c > index 39ddea3..a173afc 100644 > --- a/block.c > +++ b/block.c > @@ -3145,6 +3145,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, > int is_protocol = 0; > BlockDriverState *curr_bs = NULL; > BlockDriverState *retval = NULL; > + Error *local_error = NULL; > > if (!bs || !bs->drv || !backing_file) { > return NULL; > @@ -3165,6 +3166,17 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, > retval = curr_bs->backing->bs; > break; > } > + /* Also check against the full backing filename for the image */ > + bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX, > + &local_error); > + if (local_error == NULL) { > + if (strcmp(backing_file, backing_file_full) == 0) { > + retval = curr_bs->backing->bs; > + break; > + } > + } else { > + error_free(local_error); > + } > } else { > /* If not an absolute filename path, make it relative to the current > * image's filename path */ > -- > 2.9.3 >