libbb/loop: don't try to re-use existing loop device

loopinfo.lo_file_name is not enough to uniquely identify a file on a system with
multiple mount namespaces.  We could conceivably change this to dedup on
(lo_rdevice, lo_inode), but, as the comment above the deleted code notes, this
whole approach of reusing devices is racy anyway, so it seems better to stop
doing it entirely.

Signed-off-by: Kevin Wallace <k@igneous.io>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Kevin Wallace 2015-02-03 16:17:29 -08:00 committed by Denys Vlasenko
parent a03195941b
commit 782ee2aa0e

View File

@ -154,16 +154,7 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
else
ioctl(dfd, LOOP_CLR_FD, 0);
}
/* If this block device already set up right, re-use it.
* (Yes this is racy, but associating two loop devices with the same
* file isn't pretty either. In general, mounting the same file twice
* without using losetup manually is problematic.)
*/
} else
if (strcmp(file, (char *)loopinfo.lo_file_name) != 0
|| offset != loopinfo.lo_offset
) {
} else {
rc = -1;
}
close(dfd);