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 <junm...@gmail.com>
---
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
