Re: [PATCH -mm] fault-injection: reject-failure-if-any-caller-lies-within-specified range

[Akinobu Mita <akinobu.mita@gmail.com>]

On Sun, Nov 19, 2006 at 07:04:07PM -0800, Don Mullis wrote:
> /debug/fail_make_request can force a failure like the following:
> 
> 	FAULT_INJECTION: forcing a failure
...
> 	Buffer I/O error on device hda2, logical block 5782
> 	lost page write due to I/O error on hda2
> 	Aborting journal on device hda2.
> 	journal commit I/O error
> 	ext3_abort called.
> 	EXT3-fs error (device hda2): ext3_journal_start_sb: Detected aborted journal
> 	Remounting filesystem read-only
> 
> The above read-only remount effectively ends the test run.  

This test is a little intentional.
(Normal I/O may fail, but journal commit I/O doesn't fail)

If you want to do this, you could put journal on the other device.

> Implementation approach is to extend the existing
> address-start/address-end mechanism specifying a range _required_ to
> be found on the stack, by the addition of an address range to be
> _rejected_.  

The only problem about this is, the users who set reject address range really
don't want to insert failures from the address range. So they have to change
stacktrace-depth large enough. It will cause large slow down by aggressive
stacktrace and there is no guarantee to prevent from injecting failures the
address range.