[PATCH] roubust ext2fs against failure

Hirokazu Takahashi (h-takaha@mub.biglobe.ne.jp)
Sat, 14 Aug 1999 22:41:54 +0900


Hello, Remy.

I've just refined synchronous-updates-mount mode of ext2fs.
Ext2 mounted "sync" works very slow and ext2 might be damaged
seriously in an event of crash.
So I decided to redesign them.

Patch is availabe at
http://www03.u-page.so-net.ne.jp/da2/h-takaha/

This patch makes your linux:
1. robust in an event of crash.
keeping consitency of meta-data of filesystem.
2. improving performances.

The peformances of ext2fs applied this patch is bellow:
----------------------------------------------------
Machine spec: Pentium(166MHz) IDE-Disk(Western Degital AC31600H)

time cp -r src/linux /tmp time rm -r src/linux
linux 16 min 25 sec 3 min 2 sec
linux+patch 3 min 21 sec 1 min 49 sec
----------------------------------------------------

My first aproach to implement them is 'fail-safe and fail-soft':
- write meta-data back to disk in safe order.
- initialize meta-data on disk at first use.
- keep link-count of inodes zero when creating files.

Second, minimize loss of performance:
- it isn't neccesary to synhronous-update inode-bitmaps and
block-bitmaps. E2fsck will repair them perfectly.
- it isn't neccesary to synhronous-update inode and indirect-block,
this does'nt cause any problems.

Any comments any suggestions are welcome, Please e-mail me.

Regards,
Hirokazu Takahashi.

mailto:h-takaha@mub.biglobe.ne.jp
mailto:h-takaha@sss.abk.nec.co.jp

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/