From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49480) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WjAG0-0003EA-Iw for qemu-devel@nongnu.org; Sat, 10 May 2014 12:36:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WjAFu-00019f-EC for qemu-devel@nongnu.org; Sat, 10 May 2014 12:36:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27032) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WjAFu-00019Z-79 for qemu-devel@nongnu.org; Sat, 10 May 2014 12:36:10 -0400 From: Jun Li Date: Sun, 11 May 2014 00:35:57 +0800 Message-Id: <1399739757-3111-1-git-send-email-juli@redhat.com> Subject: [Qemu-devel] [PATCH v3] snapshot: fixed bdrv_get_full_backing_filename can not get correct full_backing_filename List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, juli@redhat.com, famz@redhat.com, junmuzi@gmail.com, stefanha@redhat.com From: Jun Li This patch fixed the following bug: https://bugzilla.redhat.com/show_bug.cgi?id=1084302 . path_combine can not calculate the correct full path name for backing_file. Such as: create a snapshot chain: sn2->sn1->$BASE_IMG backing file is : /home/wookpecker/img.qcow2 sn1 : /home/woodpecker/tmp/sn1 sn2 : /home/woodpecker/tmp/sn2 when create sn2, path_combine can not got a correct path for $BASE_IMG. In this patch, will check the backing_filename is a symlink or not firstly, then return the full(absolute) path via realpath. Signed-off-by: Jun Li --- block.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index b749d31..6674719 100644 --- a/block.c +++ b/block.c @@ -304,10 +304,26 @@ void path_combine(char *dest, int dest_size, void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz) { + struct stat sb; + char *linkname; + if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) { pstrcpy(dest, sz, bs->backing_file); } else { - path_combine(dest, sz, bs->filename, bs->backing_file); + if (lstat(bs->backing_file, &sb) == -1) { + perror("lstat"); + exit(EXIT_FAILURE); + } + + /* Check linkname is a link or not */ + if (S_ISLNK(sb.st_mode)) { + linkname = malloc(sb.st_size + 1); + readlink(bs->backing_file, linkname, sb.st_size + 1); + linkname[sb.st_size] = '\0'; + realpath(linkname, dest); + } else { + realpath(bs->backing_file, dest); + } } } -- 1.8.3.1