Ext4 developers,
I recently upgraded my kernel from 3.0.24 to 3.2.18, and discovered that df is now reporting different statistics for my ext4 file systems (sda1 is ext3 and unaffected). Notice the difference between the 1K-blocks column and Used column between kernel versions (Available remains constant, as it is merely Used subtracted from the total size):
3.0.24:
[root@box ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 5080796 951932 3866608 20% /
tmpfs 12368192 32 12368160 1% /dev/shm
/dev/sdb1 2907178636 205876 2906972760 1% /media/9c2fb7c6-31db-4e29-b1b4-c199261301f9
/dev/sdc1 2907178636 205876 2906972760 1% /media/a564e4e1-9b49-40f0-afbd-e0ec4789da70
/dev/sdd1 2907178636 205876 2906972760 1% /media/f628cda4-ed56-4b8d-be1e-133917569b47
/dev/sde1 2907178636 359512 2906819124 1% /media/648da0a1-3b1b-42f7-a032-d592bb1435e2
/dev/sdf1 2907178636 205876 2906972760 1% /media/ce380174-701c-43e8-8986-256d23c3cbd2
/dev/sdg1 2907178636 205876 2906972760 1% /media/a61227f7-ec93-43ba-b657-6c95b81e51e7
/dev/sdh1 2907178636 205876 2906972760 1% /media/62b23b60-b70d-4097-ba35-0ffa57de8a44
/dev/sdi1 2907178636 205876 2906972760 1% /media/479bcb00-f4b0-41e5-9a06-56f02259912c
/dev/sdj1 2907178636 359512 2906819124 1% /media/0ccf9659-15d1-4e2b-81c7-b3d1fbb61076
/dev/sdk1 2907178636 205876 2906972760 1% /media/096c90c5-b28f-409a-9f5b-8ae09569ecb0
/dev/sdl1 2907178636 205876 2906972760 1% /media/671e195b-2e10-4d2d-83cf-96fd07daf3da
/dev/sdm1 2907178636 205876 2906972760 1% /media/0ec3c3ed-374f-4d52-9ccf-f8a42fb246c5
3.2.18:
[root@box ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 5080796 953576 3864964 20% /
tmpfs 12368792 32 12368760 1% /dev/shm
/dev/sdb1 2928918024 21945264 2906972760 1% /media/9c2fb7c6-31db-4e29-b1b4-c199261301f9
/dev/sdc1 2928918024 21945264 2906972760 1% /media/a564e4e1-9b49-40f0-afbd-e0ec4789da70
/dev/sdd1 2928918024 21945264 2906972760 1% /media/f628cda4-ed56-4b8d-be1e-133917569b47
/dev/sde1 2928918024 22098900 2906819124 1% /media/648da0a1-3b1b-42f7-a032-d592bb1435e2
/dev/sdf1 2928918024 21945264 2906972760 1% /media/ce380174-701c-43e8-8986-256d23c3cbd2
/dev/sdg1 2928918024 21945264 2906972760 1% /media/a61227f7-ec93-43ba-b657-6c95b81e51e7
/dev/sdh1 2928918024 21945264 2906972760 1% /media/62b23b60-b70d-4097-ba35-0ffa57de8a44
/dev/sdi1 2928918024 21945264 2906972760 1% /media/479bcb00-f4b0-41e5-9a06-56f02259912c
/dev/sdj1 2928918024 22098900 2906819124 1% /media/0ccf9659-15d1-4e2b-81c7-b3d1fbb61076
/dev/sdk1 2928918024 21945264 2906972760 1% /media/096c90c5-b28f-409a-9f5b-8ae09569ecb0
/dev/sdl1 2928918024 21945264 2906972760 1% /media/671e195b-2e10-4d2d-83cf-96fd07daf3da
/dev/sdm1 2928918024 21945264 2906972760 1% /media/0ec3c3ed-374f-4d52-9ccf-f8a42fb246c5
I bisected the change to the following commit:
f975d6bcc7a698a10cc755115e27d3612dcfe322 is the first bad commit
commit f975d6bcc7a698a10cc755115e27d3612dcfe322
Author: Theodore Ts'o<tytso@xxxxxxx>
Date: Fri Sep 9 19:00:51 2011 -0400
ext4: teach ext4_statfs() to deal with clusters if bigalloc is enabled
Signed-off-by: "Theodore Ts'o"<tytso@xxxxxxx>
Reverting this commit on top of 3.2.18 returns the output to pre-3.2 levels.
Here's my /proc/mounts:
[root@box ~]# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw,relatime,errors=continue,user_xattr,acl,barrier=1,data=ordered 0 0
/dev /dev tmpfs rw,relatime,mode=755 0 0
/proc /proc proc rw,relatime 0 0
/sys /sys sysfs rw,relatime 0 0
devpts /dev/pts devpts rw,relatime,gid=5,mode=620 0 0
tmpfs /dev/shm tmpfs rw,relatime 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw,relatime 0 0
/dev/sdb1 /media/9c2fb7c6-31db-4e29-b1b4-c199261301f9 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdc1 /media/a564e4e1-9b49-40f0-afbd-e0ec4789da70 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdd1 /media/f628cda4-ed56-4b8d-be1e-133917569b47 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sde1 /media/648da0a1-3b1b-42f7-a032-d592bb1435e2 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdf1 /media/ce380174-701c-43e8-8986-256d23c3cbd2 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdg1 /media/a61227f7-ec93-43ba-b657-6c95b81e51e7 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdh1 /media/62b23b60-b70d-4097-ba35-0ffa57de8a44 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdi1 /media/479bcb00-f4b0-41e5-9a06-56f02259912c ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdj1 /media/0ccf9659-15d1-4e2b-81c7-b3d1fbb61076 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdk1 /media/096c90c5-b28f-409a-9f5b-8ae09569ecb0 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdl1 /media/671e195b-2e10-4d2d-83cf-96fd07daf3da ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/sdm1 /media/0ec3c3ed-374f-4d52-9ccf-f8a42fb246c5 ext4 rw,noatime,user_xattr,barrier=1,data=ordered 0 0
Is this discrepancy between the df outputs on the two kernel versions
expected given my mount options? I decided to come to the list
because I don't have the technical depth with regard to ext4 to be
able to analyze the ext4_statfs changes that went into making
bigalloc work, and I haven't found any reports of similar symptoms
via web searches or the Documentation/filesystems/ext4.txt. This is
