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bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts
From: |
Dave Chiluk |
Subject: |
bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts |
Date: |
Fri, 11 Sep 2015 16:55:07 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 |
On 09/11/2015 03:42 PM, Pádraig Brady wrote:
> On 31/08/15 22:05, 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..00c77c1 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. */
>> + /* Only if it's 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))))
>
> As previously mentioned, should this be >= ?
Sorry my apologies for not addressing that. I don't think it should be
(strlen (devlist->me->me_mntroot)>= strlen(me->me_mntroot)), because
that would give preference to later mounts of the same me_mntroot
directory *(I'm specifically thinking of the case where both me_mntroot
= "/").
However, looking at the code again, I realized that by adding the NULL
checks I have actually changed the behavior for non-linux OS's since the
NULL checks would always defeat the (strlen (devlist->me->me_mountdir) >
strlen (me->me_mountdir) check.
I'm going to think through this nasty if case and see if I can make it
prettier.
>
> We'll need to look at tests.
> This will be quite tricky given the current
> avoidance of /proc/self/mountinfo in tests.
> I'll look at adding a separate test for this.
>
> thanks,
> Pádraig.
>
Additionally I agree with you that we should mirror the find_mnt
bracketting behavior.
/dev/sdb2 xfs 12.7G 9.4G 3.3G 74% /
/dev/sdb2[/etc] xfs /root/chroot
I'll submit that in a different patch once we have this more squared away.
Thanks,
Dave.
- bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts, Pádraig Brady, 2015/09/11
- bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts,
Dave Chiluk <=
- bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts, Pádraig Brady, 2015/09/11
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Dave Chiluk, 2015/09/21
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Pádraig Brady, 2015/09/21
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Pádraig Brady, 2015/09/21
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Dave Chiluk, 2015/09/22
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Dave Chiluk, 2015/09/22
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Pádraig Brady, 2015/09/22
- bug#21372: [PATCH v4] df: fix prioritize real mounts over bind mounts, Dave Chiluk, 2015/09/23