Hi,
I have now evacuated the data on the filesystem and I *did* manage to
recreate the
"Should never happen: resize inode corrupt!" using the versions of
e2fsprogs I believe I was using at the time.
The vast majority of the data that I was able to checksum was ok.
For me I guess the way forward should be to recreate the fs with 1.42.13
and stick to online resize
from now on, correct?
Are there any feature flags that I should not use when expanding file
systems or any that I must use?
-johan
Here is a step by step of what I did to reproduce
I have built the following two versions of e2fsprogs (configure, make,
make install, nothing else):
421d693 (HEAD) libext2fs: fix potential buffer overflow in closefs()
6a3741a (tag: v1.42.12) Update release notes, etc. for final 1.42.12 release
9779e29 (HEAD, tag: v1.42.10) Update release notes, etc. for final
1.42.10 release
===
First build the fs with 1.42.10 with the exact number of blocks I
originally had.
# MKE2FS_CONFIG=/root/e10/out/etc/mke2fs.conf
/root/e10/out/sbin/mkfs.ext4 /dev/md0 -i 262144 -m 0 -O 64bit 15627548672k
mke2fs 1.42.10 (18-May-2014)
/dev/md0 contains a ext4 file system
created on Sat Sep 12 11:23:02 2015
Proceed anyway? (y,n) y
Creating filesystem with 3906887168 4k blocks and 61045248 inodes
Filesystem UUID: d00e9e59-3756-4e59-9539-bc00fe2446b5
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632,
2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848, 512000000, 550731776, 644972544, 1934917632,
2560000000, 3855122432
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
From dumpe2fs I observe:
1) the fs features match what I had on my broken fs
2) the number of free blocks is 512088558484167 which is clearly wrong.
# e2fsck -fnv /dev/md0
e2fsck 1.42.13 (17-May-2015)
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
Free blocks count wrong (512088558484167, counted=3902749383).
Fix? no
So the initial fs created by 1.42.10 appear to be bad.
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: d00e9e59-3756-4e59-9539-bc00fe2446b5
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index
filetype extent 64bit flex_bg sparse_super large_file huge_file
uninit_bg dir_nlink extra_isize
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 61045248
Block count: 3906887168
Reserved block count: 0
Free blocks: 512088558484167
Free inodes: 61045237
First block: 0
Block size: 4096
Fragment size: 4096
Group descriptor size: 64
Reserved GDT blocks: 185
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 512
Inode blocks per group: 32
Flex block group size: 16
Filesystem created: Sat Sep 12 11:27:55 2015
Last mount time: n/a
Last write time: Sat Sep 12 11:27:55 2015
Mount count: 0
Maximum mount count: -1
Last checked: Sat Sep 12 11:27:55 2015
Check interval: 0 (<none>)
Lifetime writes: 158 MB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: f252a723-7016-43d1-97f8-579062a215e1
Journal backup: inode blocks
Journal features: (none)
Journal size: 128M
Journal length: 32768
Journal sequence: 0x00000001
Journal start: 0
The next step is resizing + 4 TB with 1.42.12.
# MKE2FS_CONFIG=/root/e12/out/etc/mke2fs.conf
/root/e12/out/sbin/resize2fs -p /dev/md0 19534435840k
resize2fs 1.42.12 (29-Aug-2014)
<and nothing more>
It did *not* print the "Resizing the filesystem on /dev/md0 to
4883608960 (4k) blocks." that it should have.
I let it run for 90+ minutes sampling CPU and IO usage with iotop from
time to time. It was using more or less 100% CPU and no visible io.
So, I let e2fsck fix the free block count and re-did the resize:
# e2fsck -f /dev/md0
e2fsck 1.42.13 (17-May-2015)
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
Free blocks count wrong (512088558484167, counted=3902749383).
Fix<y>? yes
/dev/md0: ***** FILE SYSTEM WAS MODIFIED *****
/dev/md0: 11/61045248 files (0.0% non-contiguous), 4137785/3906887168 blocks
# MKE2FS_CONFIG=/root/e12/out/etc/mke2fs.conf
/root/e12/out/sbin/resize2fs -p /dev/md0 19534435840k
resize2fs 1.42.12 (29-Aug-2014)
Resizing the filesystem on /dev/md0 to 4883608960 (4k) blocks.
Begin pass 2 (max = 6)
Relocating blocks XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 119229)
Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 5 (max = 8)
Moving inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/md0 is now 4883608960 (4k) blocks long.
dumpe2fs 1.42.13 (17-May-2015)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 159d3929-1842-4f8d-907f-7509c16f06df
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index
filetype extent 64bit flex_bg sparse_super large_file huge_file
uninit_bg dir_nlink extra_isize
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 76306432
Block count: 4883608960
Reserved block count: 0
Free blocks: 4878450712
Free inodes: 76306421
First block: 0
Block size: 4096
Fragment size: 4096
Group descriptor size: 64
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 512
Inode blocks per group: 32
RAID stride: 32752
Flex block group size: 16
Filesystem created: Sat Sep 12 11:41:10 2015
Last mount time: n/a
Last write time: Sat Sep 12 11:56:20 2015
Mount count: 0
Maximum mount count: -1
Last checked: Sat Sep 12 11:49:28 2015
Check interval: 0 (<none>)
Lifetime writes: 279 MB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: feeea566-bb38-44c6-a4d5-f97aa78001d4
Journal backup: inode blocks
Journal features: (none)
Journal size: 128M
Journal length: 32768
Journal sequence: 0x00000001
Journal start: 0
Looking good so far, and now for the final resize to 24 TB using 1.42.13:
# resize2fs -p /dev/md0
resize2fs 1.42.13 (17-May-2015)
Resizing the filesystem on /dev/md0 to 5860330752 (4k) blocks.
Begin pass 2 (max = 6)
Relocating blocks XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 149036)
Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 5 (max = 14)
Moving inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Should never happen: resize inode corrupt!
# dumpe2fs -h /dev/md0
dumpe2fs 1.42.13 (17-May-2015)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 159d3929-1842-4f8d-907f-7509c16f06df
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index
filetype extent 64bit flex_bg sparse_super large_file huge_file
uninit_bg dir_nlink extra_isize
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean with errors
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 91568128
Block count: 5860330752
Reserved block count: 0
Free blocks: 5853069550
Free inodes: 91568117
First block: 0
Block size: 4096
Fragment size: 4096
Group descriptor size: 64
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 512
Inode blocks per group: 32
RAID stride: 32752
Flex block group size: 16
Filesystem created: Sat Sep 12 11:41:10 2015
Last mount time: n/a
Last write time: Sat Sep 12 12:03:55 2015
Mount count: 0
Maximum mount count: -1
Last checked: Sat Sep 12 11:49:28 2015
Check interval: 0 (<none>)
Lifetime writes: 279 MB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: feeea566-bb38-44c6-a4d5-f97aa78001d4
Journal backup: inode blocks
Journal superblock magic number invalid!
On 2015-09-04 00:16, Johan Harvyl wrote:
Hello again,
I finally got around to dig some more into this and made what I
consider some good progress as I am now able to mount the filesystem
read-only so I thought I would update this thread a bit.
Short one sentence recap since it's been a while since the original
post: I am trying to recover a filesystem that was quite badly damaged
by an offline resize2fs of a fairly modern ext4fs from 20 TB to 24 TB.
I spent a lot of time trying to get something meaningful out of
e2fsck/debugfs and learned quite a bit in the process and I would like
to briefly share some observations.
1) The first hurdle running e2fsck -fnv is that the "Superblock has an
invalid journal (inode 8)" is considered fatal and cannot be fixed, at
least not in r/o mode so e2fsck just stops, this check needed to go away.
2) e2fsck gets utterly confused by the "bad block inode" that
incorrectly gets identified as having something worth looking at and
spends days iterating through blocks (before I cancelled it). Removing
handling if ino == EXT2_BAD_INO in pass1 and pass1b made things a bit
better.
3) e2fsck using a backup superblock
ext2fs_check_desc: Corrupt group descriptor: bad block for inode table
e2fsck: Group descriptors look bad... trying backup blocks...
This is bad, as it means using a superblock that has not been updated
with the +4TB. Consequently it gets the location of the first block
group wrong, or at the very least the first inode table that houses
the root inode.
Forcing it to use the master superblock again makes things a bit better.
I have some logs from various e2fsck runs with various amounts of
hacks applied if they are of any interest to developers? I will also
likely have the filesystem in this state for a week or two more if any
other information I can extract is of interest to figure out what made
resize2fs screw things up.
In the end, the only actual change I have made to the filesystem to
make it mountable is that I borrowed a root inode from a different
filesystem and updated the i_block pointer to point to the extent tree
corresponding to the root inode of my broken filesystem which was
quite easy to find by just looking for the string "lost+found".
# mount -o ro,noload /dev/md0 /mnt/loop
[2815465.034803] EXT4-fs (md0): mounted filesystem without journal.
Opts: noload
# df -h /dev/md0
Filesystem Size Used Avail Use% Mounted on
/dev/md0 22T -382T 404T - /mnt/loop
Uh oh, does not look to good.. But hey, doing some checks on the data
contents and so far results are very promising. An "ls /" looks good
and so does a lot of the data that I can verify checksums on, checks
are still running...
I really do not know how to move on with trying to repair the
filesystem with e2fsck. I do not feel brave enough to let it run r/w
on the given how many hacks that I consider very dirty were required
to even get it this far. At this point letting it make changes to the
filesystem may actually make it worse so I see no other way forward
than extracting all the contents and recreating the filesystem from
scratch.
Question is though, what is the recommended way to create the
filesystem? 64bit is clearly necessary, but what about the other
feature flags like flex_bg/meta_bg/resize_inode...? I do not care much
about slight gains in performance, robustness is more important, and
that it can be resized in the future.
Only online resize from now on, never offlline, I learned that lesson...
Will it be possible to expand from 24 TB to 28 TB online?
thanks,
-johan
On 2015-08-13 20:12, Johan Harvyl wrote:
On 2015-08-13 15:27, Theodore Ts'o wrote:
On Thu, Aug 13, 2015 at 12:00:50AM +0200, Johan Harvyl wrote:
I'm not aware of any offline resize with 1.42.13, but it sounds like
you were originally using mke2fs and resize2fs 1.42.10, which did
have
some bugs, and so the question is what sort of might it might have
left things.
What kind of bugs are we talking about, mke2fs? resize2fs? e2fsck? Any
specific commits of interest?
I suspect it was caused by a bug in resize2fs 1.42.10. The problem is
that off-line resize2fs is much more powerful; it can handle moving
file system metadata blocks around, so it can grow file systems in
cases which aren't supported by online resize --- and it can shrink
file systems when online resize doesn't support any kind of file
system shrink. As such, the code is a lot more complicated, whereas
the online resize code is much simpler, and ultimately, much more
robust.
Understood, so would it have been possible to move from my 20 TB ->
24 TB fs with
online resize? I am confused by the threads I see on the net with
regards to this.
Can you think of why it would zero out the first thousands of
inodes, like the root inode, lost+found and so on? I am thinking
that would help me assess the potential damage to the files. Could I
perhaps expect the same kind of zeroed out blocks at regular
intervals all over the device?
I didn't realize that the first thousands of inodes had been zeroed;
either you didn't mention this earier or I had missed that from your
e-mail. I suspect the resize inode before the resize was pretty
terribly corrupted, but in a way that e2fsck didn't complain.
Hi,
I may not have been clear on that it was not just the first handful
of inodes.
When I manually sampled some inodes with debugfs and a disk editor,
the first group
I found valid inodes in was:
Group 48: block bitmap at 1572864, inode bitmap at 1572880, inode
table at 1572896
With 512 inodes per group that would mean at least some 24k inodes
are blanked out,
but I did not check them all, I just sampled groups manually so there
could be some
valid in some of the groups below group 48 or a lot more invalid
afterwards.
I'll have to try to reproduce the problem based how you originally
created and grew the file system and see if I can somehow reproduce
the problem. Obviously e2fsck and resize2fs should be changed to make
this operation much more robust. If you can tell me the exact
original size (just under 16TB is probably good enough, but if you
know the exact starting size, that might be helpful), and then steps
by which the file system was grown, and which version of e2fsprogs was
installed at the time, that would be quite helpful.
Thanks,
- Ted
Cool, I will try to go through its history in some detail below.
If you have ideas on what I could look for, like ideas on if there is
a particular periodicity
to the corruption I can write some python to explore such theories.
The filesystem was originally created with e2fsprogs 1.42.10-1 and
most likely linux-image
3.14 from Debian.
# mkfs.ext4 /dev/md0 -i 262144 -m 0 -O 64bit
mke2fs 1.42.10 (18-May-2014)
Creating filesystem with 3906887168 4k blocks and 61045248 inodes
Filesystem UUID: 13c2eb37-e951-4ad1-b194-21f0880556db
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736,
1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616,
78675968,
102400000, 214990848, 512000000, 550731776, 644972544,
1934917632,
2560000000, 3855122432
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
#
It was expanded with 4 TB (another 976721792 4k blocks). Best I can
tell from my logs this
was done with either e2fsprogs:amd64 1.42.12-1 or 1.42.12-1.1 (debian
packages) and
Linux 3.16. Everything was running fine after this.
NOTE #1: It does *not* look like this filesystem was ever touched by
resize2fs 1.42.10.
NOTE #2: The diff between debian packages 1.42.12-1 and 1.42.12-1.1
appear to be this:
49d0fe2 libext2fs: fix potential buffer overflow in closefs()
Then for the final 4 TB for a total of 5860330752 4k blocks which was
done with
e2fsprogs:amd64 1.42.13-1 and Linux 4.0. This is where the:
"Should never happen: resize inode corrupt"
was seen.
In both cases the same offline resize was done, with no exotic options:
# umount /dev/md0
# fsck.ext4 -f /dev/md0
# resize2fs /dev/md0
thanks,
-johan
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