If an image references a backing file that doesn't exist, qemu-img info fails
to open this image. Exactly in this case the info would be valuable, though:
the user might want to find out which file is missing.
This patch introduces a BDRV_O_NO_BACKING flag to ignore the backing file when
opening the image. qemu-img info is the first user and provides info now even
if the backing file is invalid.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block.c | 4 ++--
block.h | 1 +
qemu-img.c | 2 +-
3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/block.c b/block.c
index 30ae2b1..994109e 100644
--- a/block.c
+++ b/block.c
@@ -477,7 +477,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename,
int flags,
unlink(filename);
}
#endif
- if (bs->backing_file[0] != '\0') {
+ if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') {
/* if there is a backing file, use it */
BlockDriver *back_drv = NULL;
bs->backing_hd = bdrv_new("");
@@ -1352,7 +1352,7 @@ const char *bdrv_get_encrypted_filename(BlockDriverState
*bs)
void bdrv_get_backing_filename(BlockDriverState *bs,
char *filename, int filename_size)
{
- if (!bs->backing_hd) {
+ if (!bs->backing_file) {
pstrcpy(filename, filename_size, "");
} else {
pstrcpy(filename, filename_size, bs->backing_file);
diff --git a/block.h b/block.h
index fa51ddf..f660d5f 100644
--- a/block.h
+++ b/block.h
@@ -39,6 +39,7 @@ typedef struct QEMUSnapshotInfo {
#define BDRV_O_NOCACHE 0x0020 /* do not use the host page cache */
#define BDRV_O_CACHE_WB 0x0040 /* use write-back caching */
#define BDRV_O_NATIVE_AIO 0x0080 /* use native AIO instead of the thread pool
*/
+#define BDRV_O_NO_BACKING 0x0100 /* don't open the backing file */
#define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_CACHE_WB)
diff --git a/qemu-img.c b/qemu-img.c
index 1d97f2e..5ad88bf 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -884,7 +884,7 @@ static int img_info(int argc, char **argv)
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
+ if (bdrv_open2(bs, filename, BRDV_O_FLAGS | BDRV_O_NO_BACKING, drv) < 0) {
error("Could not open '%s'", filename);
}
bdrv_get_format(bs, fmt_name, sizeof(fmt_name));
--
1.6.2.5
