Bug 202403

Summary:	failed readahead spams syslog
Product:	File System	Reporter:	LimeTech (tomm)
Component:	btrfs	Assignee:	BTRFS virtual assignee (fs_btrfs)
Status:	RESOLVED CODE_FIX
Severity:	normal	CC:	dsterba
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	4.19.16	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	prevent failed readhead from spamming syslog

Description LimeTech 2019-01-24 18:52:24 UTC

Created attachment 280731 [details]
prevent failed readhead from spamming syslog

Probably due to this patch:
https://www.systutorials.com/linux-kernels/771332/btrfs-readpages-should-submit-io-as-read-ahead-linux-4-19/

When underlying device driver fails a REQ_RAHEAD the btrfs_end_io() function generates a syslog message.  This patch fixes it, but maybe a btrfs developer has a better method?

-tom

Comment 1 David Sterba 2019-01-25 12:10:40 UTC

Thanks for pointing it out, I've never seen the patch that added the REQ_RAHEAD bit as it was not CCed to the mailinglist. Readahead could fail for various reasons but should not be considered a hard error, unlike proper reads.

The proposed fix looks correct to me.

Comment 2 David Sterba 2019-03-07 14:56:33 UTC

Patch submitted https://patchwork.kernel.org/patch/10843055/ , queued for some 5.1-rc. Thanks for the report and fix.