linux-ext4 - Re: ext4 filesystem bad extent error review

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <52C6F944.4030605@redhat.com>
Date:	Fri, 03 Jan 2014 11:54:12 -0600
From:	Eric Sandeen <sandeen@...hat.com>
To:	"Theodore Ts'o" <tytso@....edu>
CC:	"Huang Weller (CM/ESW12-CN)" <Weller.Huang@...bosch.com>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
	"Juergens Dirk (CM-AI/ECO2)" <Dirk.Juergens@...bosch.com>
Subject: Re: ext4 filesystem bad extent error review

On 1/3/14, 11:51 AM, Theodore Ts'o wrote:
> On Fri, Jan 03, 2014 at 11:23:54AM -0600, Eric Sandeen wrote:
>>> The BLKFLSBUF ioctl does __not__ send a CACHE FLUSH command to the
>>> hardware device.  It forces all of the dirty buffers in memory to the
>>> storage device, and then it invalidates all the buffer cache, but it
>>> does not send a CACHE FLUSH command to the hardware.  Hence, the
>>> hardware is free to write it to its on-disk cache, and not necessarily
>>> guarantee that the data is written to stable store.  (For an example
>>> use case of BLKFLSBUF, we use it in e2fsck to drop the buffer cache
>>> for benchmarking purposes.)
>>
>> Are you sure?  for a bdev w/ ext4 on it:
>>
>> BLKFLSBUF
>> 	fsync_bdev
>> 		sync_filesystem
>> 			sync_fs
>> 				ext4_sync_fs
>> 					blkdev_issue_flush
> 
> This call chain only happens if the block device is mounted.

Sure, but I thought that's what they were doing.  Maybe I misread.

-Eric


--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html