I noticed a problem when doing ext4 online resizing and using according resize parameters when creating the file system to allow for larger size increase. The problem was initially found on kernel v4.14.65, but I could verify that it is still present in v4.19-rc2. The script performs the following actions: - a logical volume is created - a new file system is created within - the file system is mounted - the logical volume size is increased - the file system is resized => here the df already reports a free size larger than the size of the file system df -h /mnt Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg-foo31 1.1G -16T 17T - /mnt - the file system is resized to a larger size => here the resize2fs will loop forever because a underflow happens there when processing the file system information A script for reproducing the problem as attached as reproducer, its output is attached as reproducer.log I already contacted tytso@xxxxxxx as Maintainer of the e2fsprogs and he told me it seems to be a problem with the online resizing in the kernel. I noticed that the problems disappears if I reduced the resize option to a third of the value (357913941 instead of the current 1073741824). With Regards, Torsten Hilbrich
# bash -x reproducer foo31 + set -e + VG=vg + NAME=foo31 + '[' -z foo31 ']' + lvcreate -n foo31 -L128M /dev/vg /dev/sdb: open failed: No medium found Logical volume "foo31" created. + mke2fs -F -m0 -b 4096 -t ext4 -O 'resize_inode,^has_journal' -E resize=1073741824 /dev/vg/foo31 mke2fs 1.44.3 (10-July-2018) Discarding device blocks: 4096/32768 done Creating filesystem with 32768 4k blocks and 32768 inodes Allocating group tables: 0/1 done Writing inode tables: 0/1 done Writing superblocks and filesystem accounting information: 0/1 done + mount /dev/vg/foo31 /mnt + lvextend -f --size 1708M /dev/vg/foo31 /dev/sdb: open failed: No medium found Size of logical volume vg/foo31 changed from 128.00 MiB (32 extents) to <1.67 GiB (427 extents). Logical volume vg/foo31 successfully resized. + df -h /mnt Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg-foo31 124M 2.1M 120M 2% /mnt + resize2fs /dev/vg/foo31 2361000s resize2fs 1.44.3 (10-July-2018) Filesystem at /dev/vg/foo31 is mounted on /mnt; on-line resizing required old_desc_blocks = 1, new_desc_blocks = 1 The filesystem on /dev/vg/foo31 is now 295125 (4k) blocks long. + df -h /mnt Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg-foo31 1.1G -16T 17T - /mnt + resize2fs /dev/vg/foo31 3109200s resize2fs 1.44.3 (10-July-2018) ^C
#!/bin/bash set -e VG="vg" NAME="$1" if [ -z "$NAME" ]; then echo "Need name as parameter" >&2 exit 1 fi lvcreate -n $NAME -L128M /dev/$VG mke2fs -F -m0 -b 4096 -t ext4 -O resize_inode,^has_journal -E resize=1073741824 /dev/$VG/$NAME mount /dev/$VG/$NAME /mnt lvextend -f --size 1708M /dev/$VG/$NAME df -h /mnt resize2fs /dev/$VG/$NAME 2361000s df -h /mnt resize2fs /dev/$VG/$NAME 3109200s umount /mnt
