From: Tomasz Chmielewski <mangoo@wpkg.org>
To: jim owens <jowens@hp.com>
Cc: "Pär Andersson" <paran@lysator.liu.se>, linux-btrfs@vger.kernel.org
Subject: Re: Mass-Hardlinking Oops
Date: Mon, 12 Oct 2009 22:50:05 +0200 [thread overview]
Message-ID: <4AD3967D.1070907@wpkg.org> (raw)
In-Reply-To: <4AD35667.3020103@hp.com>
jim owens wrote:
> P=C3=A4r Andersson wrote:
>> I just ran into the max hard link per directory limit, and remembere=
d
>> this thread. I get EMLINK when trying to create more than 311 (not 2=
72)
>> links in a directory, so at least the BUG() is fixed.
>>
>> What is the reason for the limit, and is there any chance of increas=
ing
>> it to something more reasonable as Mikhail suggested?
>>
>> For comparison I tried to create 200k hardlinks to the the same file=
in
>> the same directory on btrfs, ext4, reiserfs and xfs:
>=20
> what real-world application uses and needs this many hard links?
The number of links depends on the length of a filename.
Is _13_ (yes, thirteen) hardlinks in a directory a big number? I don't =
think so.
On systems storing user data, I regularly see user files having maximum=
length: mostly files=20
and/or directories saved by users using a webbrowser - the files take t=
heir name from the
website title, and these titles can be really long.
Consider that most sides of the world use UTF-8 characters, so the maxi=
mum file name is easily achieved.
Below, we hit this limit with just 13 hardlinks - it's not me to decide=
if 13 is "this many hard links".
cd /tmp
dd if=3D/dev/zero of=3Dbtrfs.img bs=3D1M count=3D400
mkfs.btrfs btrfs.img
mount -o loop btrfs /mnt/btrfs/
touch aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
i=3D1 ; while [ $i -ne 40 ] ; do
> ln $LNFILE $i$LNFILE =20
> echo $i
> i=3D$((i+1))
> done =
=
=20
1 =
=
=20
2 =
=
=20
3 =
=
=20
4 =
=
=20
5
6
7
8
9
10
11
12
13
ln: Erzeuge harte Verkn=C3=BCpfung =E2=80=9E14aaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaa=E2=80=9C =E2=87=92 =E2=80=9Eaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaa=E2=80=9C: Datei oder Verzeichnis nicht gefunden
14
ln: Erzeuge harte Verkn=C3=BCpfung =E2=80=9E15aaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaa=E2=80=9C =E2=87=92 =E2=80=9Eaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaa=E2=80=9C: Datei oder Verzeichnis nicht gefunden
15
ln: Erzeuge harte Verkn=C3=BCpfung =E2=80=9E16aaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaa=E2=80=9C =E2=87=92 =E2=80=9Eaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa=
aaaaaaaaaaaaaa=E2=80=9C: Datei oder Verzeichnis nicht gefunden
16
Message from syslogd@dom at Mon Oct 12 22:31:49 2009 ...
dom klogd: [ 9657.948456] Oops: 0000 [#1] SMP
Get=C3=B6tet
17
Message from syslogd@dom at Mon Oct 12 22:31:49 2009 ...
dom klogd: [ 9657.948459] last sysfs file: /sys/devices/system/cpu/cpu7=
/cache/index2/shared_cpu_map
Message from syslogd@dom at Mon Oct 12 22:31:49 2009 ...
dom klogd: [ 9657.948574] Stack:
Message from syslogd@dom at Mon Oct 12 22:31:49 2009 ...
dom klogd: [ 9657.948589] Call Trace:
--=20
Tomasz Chmielewski
http://wpkg.org
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prev parent reply other threads:[~2009-10-12 20:50 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-01 13:16 Mass-Hardlinking Oops Raskin Michael
2009-08-03 14:57 ` Chris Mason
2009-08-03 15:00 ` Tomasz Chmielewski
2009-08-03 20:01 ` Mikhail Raskin
2009-10-11 15:05 ` Pär Andersson
2009-10-11 22:43 ` Yan, Zheng
2009-10-12 8:07 ` Tomasz Chmielewski
2009-10-12 12:47 ` Chris Mason
2009-10-13 7:07 ` Florian Weimer
2009-10-13 7:28 ` Yan, Zheng
2009-10-14 0:29 ` Matteo Frigo
2009-10-15 17:55 ` Tracy Reed
2009-10-15 18:27 ` Tomasz Chmielewski
2009-10-15 19:15 ` Oystein Viggen
2009-10-16 22:17 ` Pär Andersson
2009-10-12 16:16 ` jim owens
2009-10-12 17:09 ` Goffredo Baroncelli
2009-10-12 18:07 ` jim owens
2009-10-12 17:42 ` John Dong
2009-10-12 18:17 ` jim owens
2009-10-12 20:04 ` Chris Mason
2009-10-12 21:51 ` berk walker
2009-10-13 0:31 ` Claudio Martins
2009-10-13 3:42 ` Anthony Roberts
2009-10-13 9:08 ` Brian Brunswick
2009-10-13 17:45 ` Zach Brown
2009-10-13 20:03 ` Chris Mason
2009-10-13 20:55 ` Zach Brown
2009-10-12 20:50 ` Tomasz Chmielewski [this message]
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