From: Jakob Unterwurzacher <jakobunt@gmail.com>
To: linux-btrfs@vger.kernel.org
Subject: Rename+crash behaviour of btrfs - nearly ext3!
Date: Mon, 17 May 2010 20:04:21 +0200 [thread overview]
Message-ID: <4BF18525.8080904@gmail.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1592 bytes --]
Hi!
Following Ubuntu's dpkg+ext4 problems I wanted to see if btrfs would
solve them all. And it nearly does! Now I wonder if the remaining 0.2
seconds window of exposing 0-size files could be closed too.
I tested using two simple scripts (attached for reference) on kernel
2.6.34-rc7:
- rentest creates files $i.tmp and renames to $i.cur,
- owtest does the same but overwrites existing $i.cur files,
letting them run for 30-50 seconds then resetting the virtual machine.
The results for ext3 are as expected: 0-size files are never exposed as
$i.cur, overwrites are atomic.
ext4 overwrites are /almost/ atomic (I get one 0-size file in owtest),
lots of 0-size files are exposed in rentest (30 seconds window).
btrfs *nearly* does as well as ext3. Overwrites are atomic.
The rentest exposes only a 0.2 seconds windows of 0-size $i.cur files,
so that a "ls --full-time" after the crash looks like this (notice the
time between 01281.cur and 01292.tmp, only 0.2 seconds):
[...]
-rw-r--r-- 1 root root 20 2010-05-17 17:06:25.812016407 +0200 01280.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:06:25.835999490 +0200 01281.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:25.868035485 +0200 01282.cur
[...]
-rw-r--r-- 1 root root 0 2010-05-17 17:06:26.080003626 +0200 01291.cur
-rw-rw-rw- 1 root root 0 2010-05-17 17:06:26.108010083 +0200 01292.tmp
Finally, xfs kills lots of existing files in owtest and exposes lots of
0-size files in rentest (both 40 seconds window).
If anybody is interested, the bunch of trimmed "ls --full-time" output
for all filesystems is attached.
Thanks,
Jakob
[-- Attachment #2: rentest --]
[-- Type: text/plain, Size: 204 bytes --]
#!/bin/bash
set -eu
cd rentest-tmp
rm -Rf *
sync
echo "$0: Running rename loop"
( sleep 30s ; echo "$0: 30s. " )&
for i in `seq -w 1 10000`
do
echo "File content $i." > $i.tmp
mv $i.tmp $i.cur
done
[-- Attachment #3: owtest --]
[-- Type: text/plain, Size: 329 bytes --]
#!/bin/bash
set -eu
cd owtest-tmp
rm -Rf *
sync
echo "$0: Running create loop"
for i in `seq -w 1 10000`
do
echo "old file content" > $i.cur
done
sync
echo "$0: Running overwrite loop"
( sleep 30s ; echo "$0: 30s" )&
for i in `seq -w 1 10000`
do
echo "new file content of different size" > $i.tmp
mv $i.tmp $i.cur
done
[-- Attachment #4: results.txt --]
[-- Type: text/plain, Size: 5295 bytes --]
Linux lucid-crash-burn 2.6.34-020634rc7-generic #020634rc7 SMP Mon May 10 10:08:20 UTC 2010 i686 GNU/Linux
########
ext3 data=ordered
########
********
rentest
********
-rw-r--r-- 1 root root 20 2010-05-17 19:05:05.000000000 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 20 2010-05-17 19:05:50.000000000 +0200 02013.cur
********
owtest
********
-rw-r--r-- 1 root root 35 2010-05-17 19:05:04.000000000 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 35 2010-05-17 19:05:50.000000000 +0200 02027.cur
-rw-r--r-- 1 root root 35 2010-05-17 19:05:50.000000000 +0200 02028.cur
-rw-r--r-- 1 root root 35 2010-05-17 19:05:50.000000000 +0200 02029.cur
-rw-r--r-- 1 root root 17 2010-05-17 19:05:03.000000000 +0200 02030.cur
-rw-r--r-- 1 root root 35 2010-05-17 19:05:50.000000000 +0200 02030.tmp
-rw-r--r-- 1 root root 17 2010-05-17 19:05:03.000000000 +0200 02031.cur
-rw-r--r-- 1 root root 17 2010-05-17 19:05:03.000000000 +0200 02032.cur
-rw-r--r-- 1 root root 17 2010-05-17 19:05:03.000000000 +0200 02033.cur
[...]
-rw-r--r-- 1 root root 17 2010-05-17 19:05:04.000000000 +0200 10000.cur
########
ext4 data=ordered
########
********
rentest
********
-rw-r--r-- 1 root root 20 2010-05-17 17:05:56.000000000 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 20 2010-05-17 17:06:06.000000000 +0200 00429.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:06:06.000000000 +0200 00430.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:06:06.000000000 +0200 00431.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:06.000000000 +0200 00432.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:06.000000000 +0200 00433.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:06.000000000 +0200 00434.cur
[...]
-rw-r--r-- 1 root root 0 2010-05-17 17:06:36.000000000 +0200 01748.cur
********
owtest
********
-rw-r--r-- 1 root root 35 2010-05-17 16:47:25.000000000 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 35 2010-05-17 16:48:01.000000000 +0200 01451.cur
-rw-r--r-- 1 root root 35 2010-05-17 16:48:01.000000000 +0200 01452.cur
-rw-r--r-- 1 root root 35 2010-05-17 16:48:01.000000000 +0200 01453.cur
-rw-r--r-- 1 root root 0 2010-05-17 16:48:01.000000000 +0200 01454.cur
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.000000000 +0200 01455.cur
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.000000000 +0200 01456.cur
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.000000000 +0200 01457.cur
[...]
-rw-r--r-- 1 root root 17 2010-05-17 16:47:24.000000000 +0200 10000.cur
########
btrfs
########
********
rentest
********
-rw-r--r-- 1 root root 20 2010-05-17 17:05:56.260291651 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 20 2010-05-17 17:06:25.788083319 +0200 01279.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:06:25.812016407 +0200 01280.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:06:25.835999490 +0200 01281.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:25.868035485 +0200 01282.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:25.887995591 +0200 01283.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:06:25.912002104 +0200 01284.cur
[...]
-rw-r--r-- 1 root root 0 2010-05-17 17:06:26.080003626 +0200 01291.cur
-rw-rw-rw- 1 root root 0 2010-05-17 17:06:26.108010083 +0200 01292.tmp
********
owtest
********
-rw-r--r-- 1 root root 35 2010-05-17 16:47:26.310637092 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 35 2010-05-17 16:47:56.770578127 +0200 01226.cur
-rw-r--r-- 1 root root 35 2010-05-17 16:47:56.794580123 +0200 01227.cur
-rw-r--r-- 1 root root 35 2010-05-17 16:47:56.818574731 +0200 01228.cur
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.122599650 +0200 01229.cur
-rw-rw-rw- 1 root root 0 2010-05-17 16:47:56.842574557 +0200 01229.new
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.122599650 +0200 01230.cur
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.122599650 +0200 01231.cur
-rw-r--r-- 1 root root 17 2010-05-17 16:47:22.122599650 +0200 01232.cur
[...]
-rw-r--r-- 1 root root 17 2010-05-17 16:47:25.906584357 +0200 10000.cur
########
xfs
########
********
rentest
********
-rw-r--r-- 1 root root 20 2010-05-17 17:45:29.856656127 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 20 2010-05-17 17:45:39.836115618 +0200 00346.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:45:39.860120683 +0200 00347.cur
-rw-r--r-- 1 root root 20 2010-05-17 17:45:39.892119985 +0200 00348.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:45:39.928119346 +0200 00349.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:45:39.964136036 +0200 00350.cur
-rw-r--r-- 1 root root 0 2010-05-17 17:45:39.992118460 +0200 00351.cur
[...]
-rw-r--r-- 1 root root 0 2010-05-17 17:46:19.036119284 +0200 01657.cur
********
owtest
********
-rw-r--r-- 1 root root 35 2010-05-17 18:02:00.046591863 +0200 00001.cur
[...]
-rw-r--r-- 1 root root 35 2010-05-17 18:02:04.886617159 +0200 00193.cur
-rw-r--r-- 1 root root 35 2010-05-17 18:02:04.906607613 +0200 00194.cur
-rw-r--r-- 1 root root 35 2010-05-17 18:02:04.930592724 +0200 00195.cur
-rw-r--r-- 1 root root 0 2010-05-17 18:02:04.958586922 +0200 00196.cur
-rw-r--r-- 1 root root 0 2010-05-17 18:02:04.982590376 +0200 00197.cur
-rw-r--r-- 1 root root 0 2010-05-17 18:02:05.006606400 +0200 00198.cur
[...]
-rw-r--r-- 1 root root 0 2010-05-17 18:02:44.878590296 +0200 01775.cur
-rw-r--r-- 1 root root 17 2010-05-17 18:01:46.674588629 +0200 01776.cur
[...]
-rw-r--r-- 1 root root 17 2010-05-17 18:01:53.202593995 +0200 10000.cur
next reply other threads:[~2010-05-17 18:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-17 18:04 Jakob Unterwurzacher [this message]
2010-05-17 19:12 ` Rename+crash behaviour of btrfs - nearly ext3! Ric Wheeler
2010-05-17 19:25 ` Josef Bacik
2010-05-17 20:09 ` Chris Mason
2010-05-17 20:30 ` Jakob Unterwurzacher
2010-05-17 19:36 ` Chris Mason
2010-05-18 0:14 ` Jakob Unterwurzacher
2010-05-18 0:30 ` Chris Mason
2010-05-18 0:59 ` Chris Mason
2010-05-18 12:03 ` Jakob Unterwurzacher
2010-05-18 13:13 ` Chris Mason
2010-05-18 13:28 ` Oystein Viggen
2010-05-18 14:47 ` Thomas Bellman
2010-05-18 13:39 ` Aidan Van Dyk
2010-05-18 14:06 ` Jakob Unterwurzacher
2010-05-18 14:36 ` Chris Mason
2010-05-18 15:57 ` Jakob Unterwurzacher
2010-05-18 16:10 ` Chris Mason
2010-05-18 18:01 ` Goffredo Baroncelli
2010-05-18 18:24 ` Jakob Unterwurzacher
2010-05-18 23:00 ` Ric Wheeler
2010-05-19 1:05 ` Bruce Guenter
2010-05-19 1:34 ` Andy Lutomirski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4BF18525.8080904@gmail.com \
--to=jakobunt@gmail.com \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.