Re: A couple of ext4 crashes with inlinedata/bigalloc

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On Wed, Apr 09, 2014 at 11:04:49AM -0700, Darrick J. Wong wrote:
> On Wed, Apr 09, 2014 at 12:56:41PM +0800, Zheng Liu wrote:
> > On Tue, Apr 08, 2014 at 11:40:03AM -0700, Darrick J. Wong wrote:
> > > On Tue, Apr 08, 2014 at 07:54:25PM +0800, Zheng Liu wrote:
> > > > On Mon, Mar 10, 2014 at 08:06:04PM -0700, Darrick J. Wong wrote:
> > > > > Hi all,
> > > > > 
> > > > > A couple of errors to complain about before I send out the e2fsprogs patchbomb.
> > > > > :)
> > > > > 
> > > > > Zheng: I've been running the metadata checksum test with inline_data set.
> > > > > flat_dir_test is a stress test which copies /usr/share/doc into a filesystem
> > > > > and then "enlarges" the directories by recursively renaming "$foo" to
> > > > > "$foo.longer", with the results below.  e2fsck complained that the directories
> > > > > involved (4156, 4251) have multiple links to the subdir inode.  I'm not sure
> > > > > what this is all about; the only (circumstantial) evidence I have is that it
> > > > > goes away if I don't turn on inline_data.
> > > > 
> > > > Hi Darrick,
> > > > 
> > > > I guess that you were talking about this bug at LSF/MM submmit this
> > > > year, right?  Thanks for reporting this bug.  I am trying to take a
> > > > closer look at it.  It would be great if you could tell me where I can
> > > > find the your test program ('flat_dir_test').
> > > 
> > > It's buried in the metadata checksum test suite, alas.  The test copies an
> > > arbitrary directory (/usr/share/doc) to the filesystem, then does a depth-first
> > > traversal of the copied tree, renaming everything it finds from "oldname" to
> > > "oldname.longer" to force the kernel to shuffle directory entries all over the
> > > place, and likely causing spill-out from formerly inlinedata directories.
> > 
> > I write a simple script to try to reproduce the problem.  But,
> > unfortunately, I failed.  The kernel is based on ext4/dev branch, and
> > e2fsprogs is based on e2fsprogs/next branch.  I paste the script below
> > and the output of 'dumpe2fs -h'.  Please let me know if I miss
> > something.
> 
> It is necessary to umount and then mount the FS in between populating the FS
> and renaming the files.  flat_dir_test also renames *everything*, which is why
> you need the "-depth" so that the renames don't break find:
> 
> find $mnt/testdir -depth | while read f; do
>         mv $f $f.longer
> done
> 
> This doesn't affect the script's ability to reproduce errors; it just makes it
> run faster.  The errors I see look like this:
> 
> [   51.207952] EXT4-fs error (device vda): ext4_generic_delete_entry:2118: inode #4332: block 687: comm mv: bad entry in directory: rec_len % 4 != 0 - offset=0(0), inode=33188, rec_len=1201, name_len=0
> [   51.221472] EXT4-fs error (device vda) in ext4_delete_entry:2178: IO failure
> [   51.230300] EXT4-fs warning (device vda): ext4_rename:3151: Deleting old file (4332), 2, error=-5
> [   51.512388] EXT4-fs error (device vda): ext4_generic_delete_entry:2118: inode #4427: block 693: comm mv: bad entry in directory: directory entry across range - offset=2056(2056), inode=1397064974, rec_len=34064, name_len=69
> [   51.524525] EXT4-fs error (device vda) in ext4_delete_entry:2178: IO failure

Welp, I figured out why this was happening -- if renaming within the same
directory causes inline data conversion during a add-then-delete-dirent
operation, the delete operation incorrectly tries to delete out of i_block
(which is now an extent tree), causing the FS error.

Patch soon.

--D

> 
> --D
> 
> > 
> > Thanks,
> >                                                 - Zheng
> > 
> > 
> > #!/bin/bash
> > 
> > dev='/dev/sda1'
> > mnt='/mnt/sda1'
> > e2fsprogs_base="$HOME/projects/ext4-dev/e2fsprogs"
> > mkfs="$e2fsprogs_base/misc/mke2fs"
> > fsck="$e2fsprogs_base/e2fsck/e2fsck"
> > 
> > sudo umount $mnt
> > sudo $mkfs -t ext4 -O inline_data,metadata_csum,64bit $dev
> > sudo mount -t ext4 $dev $mnt
> > sudo chown wenqing:wenqing $mnt
> > 
> > cd $mnt
> > mkdir testdir
> > cp -rf /usr/share/doc/* testdir/
> > 
> > function do_rename()
> > {
> > 	tmpfilename=$(mktemp --dry-run)
> > 	postfix=$(echo $tmpfilename | awk -F'/' '{print $3}')
> > 	mv "$1" "$1-$postfix"
> > }
> > 
> > function do_dir()
> > {
> > 	for ent in $1/*; do
> > 		if [ -d $ent ]; then
> > 			do_dir $ent
> > 		else
> > 			do_rename $ent
> > 		fi
> > 	done
> > }
> > 
> > do_dir $mnt/testdir
> > 
> > cd $e2fsprogs_base
> > sudo umount $mnt
> > sudo $fsck -f $dev
> > 
> > exit 0
> > 
> > 
> > dumpe2fs 1.43-WIP (4-Feb-2014)
> > Filesystem volume name:   <none>
> > Last mounted on:          /mnt/sda1
> > Filesystem UUID:          5643cf62-dd3b-4883-9991-4d7f319e3e1e
> > Filesystem magic number:  0xEF53
> > Filesystem revision #:    1 (dynamic)
> > Filesystem features:      has_journal ext_attr resize_inode dir_index filetype extent 64bit flex_bg inline_data sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
> > Filesystem flags:         signed_directory_hash 
> > Default mount options:    user_xattr acl
> > Filesystem state:         clean
> > Errors behavior:          Continue
> > Filesystem OS type:       Linux
> > Inode count:              5021696
> > Block count:              20081242
> > Reserved block count:     1004062
> > Free blocks:              19663835
> > Free inodes:              5007473
> > First block:              0
> > Block size:               4096
> > Fragment size:            4096
> > Group descriptor size:    64
> > Reserved GDT blocks:      1024
> > Blocks per group:         32768
> > Fragments per group:      32768
> > Inodes per group:         8192
> > Inode blocks per group:   512
> > Flex block group size:    16
> > Filesystem created:       Wed Apr  9 11:41:36 2014
> > Last mount time:          Wed Apr  9 11:41:42 2014
> > Last write time:          Wed Apr  9 11:43:28 2014
> > Mount count:              0
> > Maximum mount count:      -1
> > Last checked:             Wed Apr  9 11:43:28 2014
> > Check interval:           0 (<none>)
> > Lifetime writes:          1601 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:      698d5a93-bfa8-4b55-b4ab-ae94c4e9e5e0
> > Journal backup:           inode blocks
> > Checksum type:            crc32c
> > Checksum:                 0x7c4d3477
> > Journal features:         journal_64bit
> > Journal size:             128M
> > Journal length:           32768
> > Journal sequence:         0x00000017
> > Journal start:            0
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