[dm-devel] [PATCH] Fix loopback file with kpartx -av

[Mathieu Trudel-Lapierre]

Le 2016-01-20 09:53, Christophe Varoqui a écrit :
> Applied,
> thanks.
> 

This patch apparently breaks the use of loopback-mounted files if you
try to use them directly with kpartx -av.

For instance:
qemu-img create foo.img 20M
sgdisk -n 1 foo.img
kpartx -av foo.img


Fails with the following error:
device-mapper: reload ioctl on loop0p1 failed: No such device
create/reload failed on loop0p1
add map loop0p1 (0:0): 0 4192256 linear 0:0 2048


This can be fixed by stat()'ing the loop device again after picking it:

--- a/kpartx/kpartx.c
+++ b/kpartx/kpartx.c
@@ -322,6 +322,11 @@ main(int argc, char **argv){
                        loopcreated = 1;
                }
                device = loopdev;
+
+               if (stat(device, &buf)) {
+                       printf("failed to stat() %s\n", device);
+                       exit (1);
+               }
        }

        off = find_devname_offset(device);




-- 
Mathieu Trudel-Lapierre <mathieu.trudel-lapierre at canonical.com>
Freenode: cyphermox, Jabber: mathieu.tl at gmail.com
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