Date:	Tue, 1 Jul 2014 08:26:19 +0200
From:	David Jander <david@...tonic.nl>
To:	Matteo Croce <technoboy85@...il.com>
Cc:	linux-ext4@...r.kernel.org, "Theodore Ts'o" <tytso@....edu>
Subject: Re: ext4: journal has aborted


Hi,

On Mon, 30 Jun 2014 23:30:10 +0200
Matteo Croce <technoboy85@...il.com> wrote:

> I was web surfing and using gimp when:
> 
> EXT4-fs error (device sda2): ext4_mb_generate_buddy:756: group 199,
> 9414 clusters in bitmap, 9500 in gd; block bitmap corrupt.

I was about to post a related question to this list. I am also seeing these
kind of errors when using ext4 on latest mainline (I began testing with 3.15
where I saw this and now in 3.16-rc3 it is still there).
It happens almost instantly when power-cycling the system (unclean shutdown).
The next time the system boots, I get these errors.

AFAICT, you are using a pretty recent kernel. Which version exactly?

> Aborting journal on device sda2-8.
> EXT4-fs (sda2): Remounting filesystem read-only
> ------------[ cut here ]------------
> WARNING: CPU: 6 PID: 4134 at fs/ext4/ext4_jbd2.c:259
> __ext4_handle_dirty_metadata+0x18e/0x1d0()
> Modules linked in: snd_hda_codec_hdmi snd_hda_codec_realtek
> snd_hda_codec_generic ecb uvcvideo videobuf2_vmalloc videobuf2_memops
> videobuf2_core videodev ath3k btusb rts5139(C) ctr ccm iTCO_wdt bnep
> rfcomm bluetooth nls_iso8859_1 vfat fat arc4 intel_rapl
> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm
> snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm
> aesni_intel aes_x86_64 snd_seq_midi snd_seq_midi_event ath9k led_class
> glue_helper ath9k_common lrw gf128mul ath9k_hw ablk_helper cryptd ath
> mac80211 snd_rawmidi snd_seq cfg80211 radeon microcode rfkill
> snd_timer snd_seq_device sr_mod psmouse r8169 snd cdrom i915 lpc_ich
> soundcore ttm mii mfd_core drm_kms_helper drm intel_gtt agpgart
> ehci_pci mei_me xhci_hcd tpm_infineon ehci_hcd video mei wmi tpm
> backlight
> CPU: 6 PID: 4134 Comm: gimp-2.8 Tainted: G         C    3.15.0 #6
>  0000000000000009 ffffffff813acbdd 0000000000000000 ffffffff8103de3d
>  ffff8802365231a0 00000000ffffffe2 0000000000000000 ffff8800b90816c0
>  ffffffff814205a0 ffffffff8118879e 0000000000000005 ffff8802365231a0
> Call Trace:
>  [<ffffffff813acbdd>] ? dump_stack+0x41/0x51
>  [<ffffffff8103de3d>] ? warn_slowpath_common+0x6d/0x90
>  [<ffffffff8118879e>] ? __ext4_handle_dirty_metadata+0x18e/0x1d0
>  [<ffffffff8116e130>] ? ext4_dirty_inode+0x20/0x50
>  [<ffffffff811903e9>] ? ext4_free_blocks+0x539/0xa40
>  [<ffffffff8118468b>] ? ext4_ext_remove_space+0x83b/0xe60
>  [<ffffffff81186a58>] ? ext4_ext_truncate+0x98/0xc0
>  [<ffffffff8116c985>] ? ext4_truncate+0x2b5/0x300
>  [<ffffffff8116d3d8>] ? ext4_evict_inode+0x3d8/0x410
>  [<ffffffff81114a46>] ? evict+0xa6/0x160
>  [<ffffffff81109346>] ? do_unlinkat+0x186/0x2a0
>  [<ffffffff8110e51e>] ? SyS_getdents+0xde/0x100
>  [<ffffffff8110e1d0>] ? fillonedir+0xd0/0xd0
>  [<ffffffff813b2626>] ? system_call_fastpath+0x1a/0x1f
> ---[ end trace 795411398e41fbcb ]---
> EXT4: jbd2_journal_dirty_metadata failed: handle type 5 started at
> line 241, credits 91/91, errcode -30
> EXT4: jbd2_journal_dirty_metadata failed: handle type 5 started at
> line 241, credits 91/91, errcode -30<2>EXT4-fs error (device sda2) in
> ext4_free_blocks:4867: Journal has aborted
> EXT4-fs error (device sda2): ext4_ext_rm_leaf:2731: inode #8257653:
> block 6520936: comm gimp-2.8: journal_dirty_metadata failed: handle
> type 5 started at line 241, credits 91/91, errcode -30
> EXT4-fs error (device sda2) in ext4_ext_remove_space:3018: Journal has
> aborted EXT4-fs error (device sda2) in ext4_ext_truncate:4666: Journal has
> aborted EXT4-fs error (device sda2) in ext4_reserve_inode_write:4877: Journal
> has aborted
> EXT4-fs error (device sda2) in ext4_truncate:3788: Journal has aborted
> EXT4-fs error (device sda2) in ext4_reserve_inode_write:4877: Journal
> has aborted
> EXT4-fs error (device sda2) in ext4_orphan_del:2684: Journal has aborted
> EXT4-fs error (device sda2) in ext4_reserve_inode_write:4877: Journal
> has aborted

I did not get these errors. I suspect this may be a consequence of FS
corruption due to a bug in etx4.

Here's why I suspect a bug:

I am running latest git head (3.16-rc3+ as of yesterday) on an ARM system with
eMMC flash. The eMMC is formatted in SLC mode ("enhanced" mode according to
eMMC 4.41) and "reliable-writes" are enabled, so power-cycling should not
cause FS corruption in presence of a journal.

I can format the eMMC device either as EXT3 or EXT4 for the test. After
formatting and writing the rootfs to the partition I can boot successfully in
either situation. Once booted from eMMC, I start bonnie++ (to just stress the
FS for a while), and after a minute or so the board is power-cycled while
bonnie++ is still running.

Next time I boot the situation is this:

With EXT3: All seems fine, journal is replayed, no errors. I can repeat this as
many times as I want, FS stays consistent.

With EXT4: After just one power cycle I start getting this:

[    7.603871] EXT4-fs error (device mmcblk0p2): ext4_mb_generate_buddy:757: group 1, 8542 clusters in bitmap, 8550 in gd; block bitmap corrupt.
[    7.616743] JBD2: Spotted dirty metadata buffer (dev = mmcblk0p2, blocknr = 0). There's a risk of filesystem corruption in case of system crash.

If I continue the test, it doesn't take long and serious corruption starts
occurring.

Again, with EXT3 I am unable to detect any problems.

Best regards,

-- 
David Jander
Protonic Holland.
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