openkylin
/
qemu
mirror of https://gitee.com/openkylin/qemu.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

block: Open backing image in force share mode for size probe 

Management tools create overlays of running guests with qemu-img:

  $ qemu-img create -b /image/in/use.qcow2 -f qcow2 /overlay/image.qcow2

but this doesn't work anymore due to image locking:

    qemu-img: /overlay/image.qcow2: Failed to get shared "write" lock
    Is another process using the image?
    Could not open backing image to determine size.
Use the force share option to allow this use case again.

Cc: qemu-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2017-12-15 16:04:45 +08:00 committed by Kevin Wolf
parent 1ee24514ae
commit cc954f01e3
1 changed files with 2 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
block.c
View File

@ -4605,10 +4605,11 @@ void bdrv_img_create(const char *filename, const char *fmt,
back_flags = flags; back_flags = flags;
back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
backing_options = qdict_new();
if (backing_fmt) { if (backing_fmt) {
backing_options = qdict_new();
qdict_put_str(backing_options, "driver", backing_fmt); qdict_put_str(backing_options, "driver", backing_fmt);
} }
qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true);
bs = bdrv_open(full_backing, NULL, backing_options, back_flags, bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
&local_err); &local_err);