Consider these standard bind mounts on my system: $ grep sdb2 /proc/mounts /dev/sdb2 / ext4 rw,seclabel,relatime,user_xattr,barrier=1,data=ordered 0 0 /dev/sdb2 /tmp ext4 rw,seclabel,relatime,user_xattr,barrier=1,data=ordered 0 0 /dev/sdb2 /var/tmp ext4 rw,seclabel,relatime,user_xattr,barrier=1,data=ordered 0 0
Current df picks the last one: $ df -h /dev/sdb2 Filesystem Size Used Avail Use% Mounted on /dev/sdb2 13G 8.0G 4.5G 64% /var/tmp The attached patch uses the same technique as when handling non device node arguments, to use the shortest mount point: $ src/df /dev/sdb2 Filesystem Size Used Avail Use% Mounted on /dev/sdb2 13G 8.0G 4.5G 64% / thanks, Pádraig.
>From 2b2f0805bcf0cd9c1f7a4af50b4d912aa475f40e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]> Date: Wed, 4 Dec 2013 00:50:10 +0000 Subject: [PATCH] df: handle bind mounts when processing device nodes * src/df.c (get_disk): Use the same heuristic used in get_point() to select the shortest file system mount point, in an attempt to show the base mounted file system. * NEWS: Mention the bug fix. --- NEWS | 4 ++++ src/df.c | 13 ++++++++++++- 2 files changed, 16 insertions(+), 1 deletions(-) diff --git a/NEWS b/NEWS index 9274645..520e946 100644 --- a/NEWS +++ b/NEWS @@ -12,6 +12,10 @@ GNU coreutils NEWS -*- outline -*- df displayed the symlink's device rather than that for the device node. [This bug was present in "the beginning".] + df now processes disk device nodes correctly in the presence of bind mounts. + Now df shows the base mounted file system rather than the last one mounted. + [This bug was present in "the beginning".] + install now removes the target file if the strip program failed for any reason. Before, that file was left behind, sometimes even with wrong permissions. diff --git a/src/df.c b/src/df.c index 1d08869..e8c46f6 100644 --- a/src/df.c +++ b/src/df.c @@ -1062,10 +1062,21 @@ get_disk (char const *disk) if (resolved && resolved[0] == '/') disk = resolved; + size_t best_match_len = SIZE_MAX; for (me = mount_list; me; me = me->me_next) { if (STREQ (disk, me->me_devname)) - best_match = me; + { + size_t len = strlen (me->me_mountdir); + if (len < best_match_len) + { + best_match = me; + if (len == 1) /* Traditional root. */ + break; + else + best_match_len = len; + } + } } free (resolved); -- 1.7.7.6
