From ed1a495b3ccb2665a13229ca866f2115bd768d17 Mon Sep 17 00:00:00 2001 From: Pádraig Brady Date: Mon, 18 Aug 2014 17:59:26 +0100 Subject: df: improve mount point selection with inaccurate mount list v8.23 has a test failure on Fedora rawhide build servers in tests/df/skip-duplicate.sh. This was due to no '/' entry being output by df. That was due to an inaccurate /proc/mounts on the build environment as stat(/mnt/point) identified all these /proc/mounts entries as having the same device id: / rootfs / /dev/md1 /dev devtmpfs /run tmpfs /boot /dev/md0 /proc/filesystems /dev/md1 Since the device name on the right changes for a given id, that causes the entries to be continually replaced, thus resulting in no '/' entry. I'm guessing this is due to the mock environment bind mounting unneeded or sensitive items to a dummy file on the host / (/dev/md1) though have not looked into those details. So rather than relying on an accurate /proc/mounts, the attached patch takes a more conservative replacement approach and only swaps a new device entry when the mount point matches. That should handle all practical cases while also avoiding this situation. * src/df.c (filter_mount_list): Only replace entries with different device names when the mount point also matches. --- src/df.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'src') diff --git a/src/df.c b/src/df.c index 3ef5d33b0..e907b9409 100644 --- a/src/df.c +++ b/src/df.c @@ -640,13 +640,18 @@ filter_mount_list (bool devices_only) if (devlist) { - /* ...let the shorter mountdir win. */ + /* let "real" devices with '/' in the name win. */ if ((strchr (me->me_devname, '/') && ! strchr (devlist->me->me_devname, '/')) + /* let a shorter mountdir win. */ || (strlen (devlist->me->me_mountdir) > strlen (me->me_mountdir)) - /* or one overmounted on a different device. */ - || ! STREQ (devlist->me->me_devname, me->me_devname)) + /* let an entry overmounted on a different device win... */ + || (! STREQ (devlist->me->me_devname, me->me_devname) + /* ... but only when matching an exsiting mount point, to + avoid problematic replacement when given inaccurate mount + lists, seen with some chroot environments for example. */ + && STREQ (me->me_mountdir, devlist->me->me_mountdir))) { /* Discard mount entry for existing device. */ discard_me = devlist->me; -- cgit v1.2.3-54-g00ecf