Date:	Wed, 28 May 2014 22:27:33 -0700
From:	"Darrick J. Wong" <darrick.wong@...cle.com>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: more resize breakage

On Thu, May 29, 2014 at 12:22:37AM -0500, Eric Sandeen wrote:
> After considering how many resize2fs corruptions we've had, I decided to try to write a resize fuzzer which picks random parameters and sizes, and sees what happens with online & offline grow & offline shrink.  When I get it cleaner, I'll send it out to play with.
> 
> But it is indeed finding resize issues; for example, with e2fsprogs git master & v3.15-rc3,
> 
> # truncate --size=11g fsfile
> # mke2fs -t ext4 -O 64bit,^bigalloc,extent,^flex_bg,^meta_bg,resize_inode,sparse_super,^uninit_bg, -E packed_meta_blocks=0 -b 1024 -I 512 -g 3648 fsfile
> mke2fs 1.43-WIP (18-May-2014)
> Discarding device blocks: done                            
> Creating filesystem with 11534336 1k blocks and 708288 inodes
> Filesystem UUID: 25a71d26-0a54-4732-bcb5-d08bdb0878ab
> Superblock backups stored on blocks: 
> 	3649, 10945, 18241, 25537, 32833, 91201, 98497, 178753, 295489, 456001, 
> 	886465, 1251265, 2280001, 2659393, 7978177, 8758849, 11400001
> 
> Allocating group tables: done                            
> Writing inode tables: done                            
> Creating journal (32768 blocks): done
> Writing superblocks and filesystem accounting information: done
> 
> # truncate --size=35g fsfile
> # mount -o loop fsfile mnt/
> # resize2fs /dev/loop0
> resize2fs 1.43-WIP (18-May-2014)
> Filesystem at /dev/loop0 is mounted on /mnt/test2/resizefuzzer/mnt; on-line resizing required
> old_desc_blocks = 198, new_desc_blocks = 629
> The filesystem on /dev/loop0 is now 36700160 blocks long.
> 
> # umount mnt
> # e2fsck -fn fsfile 
> e2fsck 1.43-WIP (18-May-2014)
> Pass 1: Checking inodes, blocks, and sizes
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Pass 4: Checking reference counts
> Pass 5: Checking group summary information
> Block bitmap differences:  +54721 +(54723--54732) +54734 +54736 +54741 +(54743--54745) +(54747--54752) +(54755--54764) +54766 +54768 +54773 +(54775--54777) +(54779--54786) +(54788--54796) +54798 +54800 +54805 +(54807--54809) +(54811--54816) +54818 +(54821--54822) +54826 +(54829--54834) -(54838--54840) -54867 -55234 -55239 -(55242--55245) -55247 -(55249--55252) -55254 -55258 -(55265--55266) -55271 -(55274--55277) -55279 -(55281--55284) -55286 -55290 -55299 -55303 -(55306--55309) -55311 -(55313--55316) -55318 -55322 -55329 -(55331--55332) -(55335--55337) -(55339--55340) -(55350--55352) -55379 -55745 -55752 -(55755--55756) -(55758--55759) -(55761--55764) -55766 -55770 -55778 -55784 -(55787--55788) -(55790--55791) -(55793--55796) -55798 -55802 -(55809--55810) -55816 -(55819--55820) -(55822--55823) -(55825--55828) -55830 -55834 -(55842--55844) -(55847--55849) -(55851--55852) -(55862--55864) -55891 -56257 -(56263--56264) -56266 -(56268--56271) -(56273--56276) -56278 -56282 -56290 !
>  -(56295--5
> 6296) -56298 -(56300--56303) -(56305--56308) -56310 -56314 -(56321--56322) -(56327--56328) -56330 -(56332--56335) -(56337--56340) -56342 -56346 -(56354--56356) -(56359--56361) -(56363--56364) -(56374--56376) -56403 -56769 -56777 -56780 -(56784--56788) -56790 -56794 -56802 -56809 -56812 -(56816--56820) -56822 -56826 -(56833--56834) -56841 -56844 -(56848--56852) -56854 -56858 -(56866--56868) -(56871--56873) -(56875--56876) -(56886--56888) -56915 -57281 -57287 -(57289--57291) -57293 -(57296--57300) -57302 -57306 -57314 -57319 -(57321--57323) -57325 -(57328--57332) -57334 -57338 -(57345--57346) -57351 -(57353--57355) -57357 -(57360--57364) -57366 -57370 -(57378--57380) -(57383--57385) -(57387--57388) -(57398--57400) -57427 -57793 -(57800--57801) -57803 -57806 -(57808--57812) -57814 -57818 -57826 -(57832--57833) -57835 -57838 -(57840--57844) -57846 -57850 -(57857--57858) -(57864--57865) -57867 -57870 -(57872--57876) -57878 -57882 -(57890--57892) -(57895--57897) -(57899--57900) -(!
>  57910--579
> 12) -57939 -58305 -(58311--58314) -(58317--58318) -(58320--58324) -58326 -58330 -58338 -(58343--58346) -(58349--58350) -(58352--58356) -58358 -58362
> Fix? no
> 
> Free blocks count wrong for group #15 (3534, counted=3280).
> Fix? no
> 
> Free blocks count wrong (35511254, counted=35511000).
> Fix? no
> 
> 
> fsfile: ********** WARNING: Filesystem still has errors **********
> 
> fsfile: 11/2253664 files (0.0% non-contiguous), 1188906/36700160 blocks
> 
> Sad face.  :(

D'oh!

/me wonders, is offline grow any better?

Also I "extended" fsfuzz to corrupt only metadata blocks and made the
kernel+e2fsck chew through all that crap.  The kernel survived, but e2fsck
seemed to die either failing to allocate blocks to resurrect the journal (bad
bbitmap) or because of that thing where calling block_iterate on an inline data
file makes e2fsck abort.

So, uh, ... long live the patchbomb? :(

--D

> 
> I haven't looked into these failures, but it seems clear that "we're not there, yet."
> 
> Resize seems to be getting so fiendishly complex with all the format options it must cope with.
> 
> -Eric
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