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bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts
From: |
Pádraig Brady |
Subject: |
bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts |
Date: |
Fri, 11 Sep 2015 23:02:33 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 |
On 11/09/15 22:55, Dave Chiluk wrote:
> 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.
Well I mentioned that df was "DEVICE oriented" and so should
probably not worry about distinguishing that, especially as
the functionality is already provided by findmnt(1).
thanks,
Pádraig
- 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, 2015/09/11
- bug#21372: [PATCH] df: fix prioritize real mounts over bind mounts,
Pádraig Brady <=
- 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