On Mon, Jun 24, 2019 at 5:48 PM Qu Wenruo <quwenruo.bt...@gmx.com> wrote:
>
> The problem is not complex, one inode which shouldn't go through
> compression (maybe nodatacow or nodatasum set) has go through compression.
>
> This leads to missing csum while still compressed.
>
> This could cause read time error.
>
> The solution should be pretty easy, find inode 4665463 in root 492, and
> remove it.
They are systemd journals. Based on the ctime/mtime they were clearly
modified today, which I don't understand because I've had volatile
journal set for a few days now. But you can see they are set to nocow,
and yet there are zstd compressed extents. We've discussed the case
before, where defragmenting a nocow file while the file system is
mounted with compress option, permits compression. I think that's
what's going on here. I've seen it with zlib and lzo too, but I
haven't used them in years so I don't know if that's still the case. I
know systemd-journald does by default set /var/log/journal with chattr
+C and also defragments journals upon rotation.
item 106 key (4665463 INODE_ITEM 0) itemoff 49169 itemsize 160
generation 57085 transid 59069 size 33554432 nbytes 33554432
block group 0 mode 100640 links 1 uid 0 gid 190 rdev 0
sequence 6143 flags 0x13(NODATASUM|NODATACOW|PREALLOC)
atime 1561330326.52881457 (2019-06-23 22:52:06)
ctime 1561390782.569639513 (2019-06-24 15:39:42)
mtime 1561390782.443639516 (2019-06-24 15:39:42)
otime 1561330326.52881457 (2019-06-23 22:52:06)
item 107 key (4665463 INODE_REF 169326) itemoff 49110 itemsize 59
index 52 namelen 49 name:
system@00058c139ef35bc6-a1c70e9eca5616e6.journal~
item 108 key (4665463 XATTR_ITEM 843765919) itemoff 49056 itemsize 54
location key (0 UNKNOWN.0 0) type XATTR
transid 57085 data_len 8 name_len 16
name: user.crtime_usec
item 109 key (4665463 XATTR_ITEM 2038346239) itemoff 48951 itemsize 105
location key (0 UNKNOWN.0 0) type XATTR
transid 57085 data_len 52 name_len 23
name: system.posix_acl_access
data
item 110 key (4665463 XATTR_ITEM 3817753667) itemoff 48874 itemsize 77
location key (0 UNKNOWN.0 0) type XATTR
transid 57085 data_len 31 name_len 16
name: security.selinux
data system_u:object_r:var_log_t:s0
item 111 key (4665463 EXTENT_DATA 0) itemoff 48821 itemsize 53
generation 59069 type 1 (regular)
extent data disk byte 1115086848 nr 16384
extent data offset 0 nr 131072 ram 131072
extent compression 3 (zstd)
Anyway the problem looks minor, the file system itself is fine. But it
does stop the startup process.
--
Chris Murphy
