Re: [PATCH] ReiserFS v3 I/O error handling

[Alex Zarochentsev <zam@namesys.com>]

Hi Jeff,

On Mon, Sep 13, 2004 at 06:11:59PM -0400, Jeff Mahoney wrote:
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> Hey all -
> 
> One of the most common complaints I've heard about ReiserFS is how
> graceless it is in handling critical I/O errors.
> 
> ext[23] can handle I/O errors anywhere, with the results being up to the
> system admin to determine: continue, go read only, or panic.
> 
> ReiserFS doesn't offer the admin any such choice, instead panicking on
> any I/O error in the journal.
> 
> Attached are four patches, against 2.6.9-rc2:
> * reiserfs-cleanup-buffer-heads.diff
> 	- Cleans up handling of buffer head bitfields - uses
> 	  the kernel supplied FNS_BUFFER macros instead.
ok

> * reiserfs-cleanup-sb-journal.diff
> 	- Cleans up accessing of the journal structure, prefering
> ~          to create a temporary variable in functions that access
> ~          the journal structure non-trivially. Should make 0 difference
> ~          at compile time.
ok

> * reiserfs-write-lock.diff
> 	- Fixes two missing reiserfs_write_unlock() calls on error paths
> ~          that are unrelated to the last patch.
ok

> * reiserfs-io-error-handling.diff
> 	- Allows ReiserFS to gracefully handle I/O errors in critical
> 	  code paths. The admin has the option to go read-only or panic.
> 	  Since ReiserFS has no option to ignore the use of the journal,
> ~          the "continue" method is not enabled.

What reiserfs will do with already dirty blocks on the R/O fs.  Those blocks
remain dirty, yes?

The whole patch is enough complex, one look is not enough :) I think Elena may
do additional testing to be sure that nothing is broken while improving i/o
handling. 

> These patches have seen a lot of testing in the SuSE Linux Enterprise
> Server 9 kernel, and are considered ready for mainline.
> 
> Hans - please take a look.
> 
> Resent: Since the namesys.com mail server refuses messages over 40k,
> I've posted the patches at
> ftp://ftp.suse.com/pub/people/jeffm/reiserfs/kernel-v2.6/io-error/
> 
> - -Jeff
> 
> - --
> Jeff Mahoney
> SuSE Labs
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-- 
Alex.