On 21/09/15 23:44, Pádraig Brady wrote: > On 21/09/15 21:04, Dave Chiluk wrote: >> Fixes an issue where bind mounts with shorter mount directories than the >> original mount are prioritized when running df. The root cause of this >> is that /proc/self/mountinfo now lists the filesystem device with bind >> mounts rather than the source directory. With /etc/mtab the source >> device was listed as the originating directory so this was not an issue. >> >> More information is available here. >> https://bugs.launchpad.net/ubuntu/+source/coreutils/+bug/1432871 >> --- >> src/df.c | 9 +++++++-- >> 1 file changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/src/df.c b/src/df.c >> index 2e541b9..4a3afa2 100644 >> --- a/src/df.c >> +++ b/src/df.c >> @@ -652,9 +652,14 @@ filter_mount_list (bool devices_only) >> else if ((strchr (me->me_devname, '/') >> /* let "real" devices with '/' in the name win. */ >> && ! strchr (devlist->me->me_devname, '/')) >> - /* let a shorter mountdir win. */ >> - || (strlen (devlist->me->me_mountdir) >> + /* let a shorter mountdir win. If it's mntroot is */ >> + /* also shorter. i.e. not a bind mount. */ >> + || ((strlen (devlist->me->me_mountdir) >> > strlen (me->me_mountdir)) >> + && (devlist->me->me_mntroot == NULL >> + || me->me_mntroot == NULL >> + || (strlen (devlist->me->me_mntroot) >> + >= strlen(me->me_mntroot)))) >> /* let an entry overmounted on a new device win... >> */ >> || (! STREQ (devlist->me->me_devname, me->me_devname) >> /* ... but only when matching an existing mnt >> point, >> > > This logic looks correct thanks. > I'll adjust the comment a bit and maybe refactor > all the conditions to a single nearer_device_root boolean. > > I'll push this later on, > with the associated gnulib update.
Attached is the refactored patch, with also lots of adjustments to commit messages. I'll apply tomorrow. thanks, Pádraig.
>From 1e925a0a80a783401129dff6840709928c8cf951 Mon Sep 17 00:00:00 2001 From: Dave Chiluk <[email protected]> Date: Mon, 21 Sep 2015 15:04:11 -0500 Subject: [PATCH] df: prioritize mounts nearer the device root In the presence of bind mounts of a device, the 4th "mount root" field from /proc/self/mountinfo is now considered, so as to prefer mount points closer to the root of the device. Note on older systems with an /etc/mtab file, the source device was listed as the originating directory, and so this was not an issue. Details at http://pad.lv/1432871 * src/df.c (filter_mount_list): When deduplicating mount entries, only prefer sources nearer or at the root of the device, when the target is nearer the root of the device. * NEWS: Mention the change in behavior. --- NEWS | 3 +++ src/df.c | 12 +++++++++--- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/NEWS b/NEWS index 63574da..9aec259 100644 --- a/NEWS +++ b/NEWS @@ -17,6 +17,9 @@ GNU coreutils NEWS -*- outline -*- base64 no longer supports hex or oct --wrap parameters, thus better supporting decimals with leading zeros. + df now prefers sources towards the root of a device when + eliding duplicate bind mounted entries. + ** Improvements du no longer stats all mount points at startup, only doing so diff --git a/src/df.c b/src/df.c index 2e541b9..7b294e5 100644 --- a/src/df.c +++ b/src/df.c @@ -641,6 +641,13 @@ filter_mount_list (bool devices_only) if (devlist) { + bool target_nearer_root = strlen (devlist->me->me_mountdir) + > strlen (me->me_mountdir); + /* With bind mounts, prefer items nearer the root of the source */ + bool source_below_root = devlist->me->me_mntroot != NULL + && me->me_mntroot != NULL + && (strlen (devlist->me->me_mntroot) + < strlen(me->me_mntroot)); if (! print_grand_total && me->me_remote && devlist->me->me_remote && ! STREQ (devlist->me->me_devname, me->me_devname)) { @@ -652,9 +659,8 @@ filter_mount_list (bool devices_only) else if ((strchr (me->me_devname, '/') /* let "real" devices with '/' in the name win. */ && ! strchr (devlist->me->me_devname, '/')) - /* let a shorter mountdir win. */ - || (strlen (devlist->me->me_mountdir) - > strlen (me->me_mountdir)) + /* let points towards the root of the device win. */ + || (target_nearer_root && ! source_below_root) /* let an entry overmounted on a new device win... */ || (! STREQ (devlist->me->me_devname, me->me_devname) /* ... but only when matching an existing mnt point, -- 2.4.1
