From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58018) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fYKUC-0004tZ-D6 for qemu-devel@nongnu.org; Wed, 27 Jun 2018 20:08:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fYKU8-0004aR-C3 for qemu-devel@nongnu.org; Wed, 27 Jun 2018 20:08:32 -0400 From: Max Reitz Date: Thu, 28 Jun 2018 02:07:33 +0200 Message-Id: <20180628000745.4477-20-mreitz@redhat.com> In-Reply-To: <20180628000745.4477-1-mreitz@redhat.com> References: <20180628000745.4477-1-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v9 19/31] block: Use bdrv_dirname() for relative filenames List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Max Reitz , Kevin Wolf bdrv_get_full_backing_filename_from_filename() breaks down when it comes to JSON filenames. Using bdrv_dirname() as the basis is better because since we have BDS, we can descend through the BDS tree to the protocol layer, which gives us a greater probability of finding a non-JSON name; also, bdrv_dirname() is more correct as it allows block drivers to override the generation of that directory name in a protocol-specific way. We still need to keep bdrv_get_full_backing_filename_from_filename(), though, because it has valid callers which need it during image creation when no BDS is available yet. This makes a test case in qemu-iotest 110, which was supposed to fail, work. That is actually good, but we need to change the reference output (and the comment in 110) accordingly. Signed-off-by: Max Reitz --- block.c | 20 +++++++++++++------- tests/qemu-iotests/110 | 3 ++- tests/qemu-iotests/110.out | 2 +- 3 files changed, 16 insertions(+), 9 deletions(-) diff --git a/block.c b/block.c index ce7ff48553..c5251b10d8 100644 --- a/block.c +++ b/block.c @@ -318,16 +318,22 @@ char *bdrv_get_full_backing_filename_from_filename(const char *backed, static char *bdrv_make_absolute_filename(BlockDriverState *relative_to, const char *filename, Error **errp) { - char *bs_filename; + char *dir, *full_name; - bdrv_refresh_filename(relative_to); + if (!filename || filename[0] == '\0') { + return NULL; + } else if (path_has_protocol(filename) || path_is_absolute(filename)) { + return g_strdup(filename); + } - bs_filename = relative_to->exact_filename[0] - ? relative_to->exact_filename - : relative_to->filename; + dir = bdrv_dirname(relative_to, errp); + if (!dir) { + return NULL; + } - return bdrv_get_full_backing_filename_from_filename(bs_filename, - filename ?: "", errp); + full_name = g_strconcat(dir, filename, NULL); + g_free(dir); + return full_name; } char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp) diff --git a/tests/qemu-iotests/110 b/tests/qemu-iotests/110 index 9de7369f3a..ba1b3c6c7d 100755 --- a/tests/qemu-iotests/110 +++ b/tests/qemu-iotests/110 @@ -61,7 +61,8 @@ echo '=== Non-reconstructable filename ===' echo # Across blkdebug without a config file, you cannot reconstruct filenames, so -# qemu is incapable of knowing the directory of the top image +# qemu is incapable of knowing the directory of the top image from the filename +# alone. However, using bdrv_dirname(), it should still work. TEST_IMG="json:{ 'driver': '$IMGFMT', 'file': { diff --git a/tests/qemu-iotests/110.out b/tests/qemu-iotests/110.out index b3584ff87f..5370bc1d26 100644 --- a/tests/qemu-iotests/110.out +++ b/tests/qemu-iotests/110.out @@ -14,7 +14,7 @@ backing file: t.IMGFMT.base (actual path: TEST_DIR/t.IMGFMT.base) image: json:{"driver": "IMGFMT", "file": {"set-state.0.event": "read_aio", "image": {"driver": "file", "filename": "TEST_DIR/t.IMGFMT"}, "driver": "blkdebug", "set-state.0.new_state": 42}} file format: IMGFMT virtual size: 64M (67108864 bytes) -backing file: t.IMGFMT.base (cannot determine actual path) +backing file: t.IMGFMT.base (actual path: TEST_DIR/t.IMGFMT.base) === Backing name is always relative to the backed image === -- 2.17.1