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qemu-patch-raspberry4
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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>
(cherry picked from commit cc954f01e3)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
stable-2.11
Fam Zheng 2017-12-15 16:04:45 +08:00 committed by Michael Roth
parent 2b0c34cf61
commit 7f53a81073
1 changed files with 2 additions and 1 deletions
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block.c
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@ -4593,10 +4593,11 @@ void bdrv_img_create(const char *filename, const char *fmt,
back_flags = flags;
back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
backing_options = qdict_new();
if (backing_fmt) {
backing_options = qdict_new();
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,
&local_err);