Hi,
I've noticed that a single device partition was using metadata.single and
system.single instead of metadata.dup and system.dup. All tests to force
conversion to dup failed.
Here is how to reproduce this with an image and some very simple BTRFS commands
(Debian stretch):
$ uname -a
Linux asdasd 4.0.0-1-amd64 #1 SMP Debian 4.0.2-1 (2015-05-11) x86_64 GNU/Linux
$ btrfs --version
btrfs-progs v4.0
$ fallocate -l 8G test.img
$ mkdir mnt
$ mkfs.btrfs test.img
$ mount -o loop test.img mnt
$ touch mnt/asdasd
$ btrfs fi df mnt
Data, single: total=8.00MiB, used=64.00KiB
System, DUP: total=8.00MiB, used=16.00KiB
System, single: total=4.00MiB, used=0.00B
Metadata, DUP: total=409.56MiB, used=112.00KiB
Metadata, single: total=8.00MiB, used=0.00B
GlobalReserve, single: total=16.00MiB, used=0.00B
$ btrfs balance start -v -mconvert=single -sconvert=single -dconvert=single mnt
-f
Dumping filters: flags 0xf, state 0x0, force is on
DATA (flags 0x100): converting, target=281474976710656, soft is off
METADATA (flags 0x100): converting, target=281474976710656, soft is off
SYSTEM (flags 0x100): converting, target=281474976710656, soft is off
Done, had to relocate 5 out of 5 chunks
$ btrfs fi df mnt
Data, single: total=832.00MiB, used=256.00KiB
System, single: total=32.00MiB, used=16.00KiB
Metadata, single: total=256.00MiB, used=112.00KiB
GlobalReserve, single: total=16.00MiB, used=0.00B
$ btrfs balance start -v -mconvert=dup -sconvert=dup -dconvert=single mnt -f
Dumping filters: flags 0xf, state 0x0, force is on
DATA (flags 0x100): converting, target=281474976710656, soft is off
METADATA (flags 0x100): converting, target=32, soft is off
SYSTEM (flags 0x100): converting, target=32, soft is off
Done, had to relocate 3 out of 3 chunks
$ btrfs fi df mnt
Data, single: total=832.00MiB, used=320.00KiB
System, single: total=32.00MiB, used=16.00KiB
Metadata, single: total=256.00MiB, used=112.00KiB
GlobalReserve, single: total=16.00MiB, used=0.00B
The expected result would be Metadata, DUP and System, DUP and not
Metadata, single and System, single
Some more info.
$ btrfs fi show mnt
Label: none uuid: b1a70fc4-7c18-4929-9b73-8f8bb328e7de
Total devices 1 FS bytes used 384.00KiB
devid1 size 8.00GiB used 1.09GiB path /dev/loop0
btrfs-progs v4.0
$ btrfs fi usage mnt
Overall:
Device size: 8.00GiB
Device allocated: 1.09GiB
Device unallocated:6.91GiB
Device missing: 0.00B
Used:384.00KiB
Free (estimated): 7.72GiB (min: 7.72GiB)
Data ratio: 1.00
Metadata ratio: 1.00
Global reserve: 16.00MiB (used: 0.00B)
Data,single: Size:832.00MiB, Used:256.00KiB
/dev/loop0832.00MiB
Metadata,single: Size:256.00MiB, Used:112.00KiB
/dev/loop0256.00MiB
System,single: Size:32.00MiB, Used:16.00KiB
/dev/loop0 32.00MiB
Unallocated:
/dev/loop0 6.91GiB
$ btrfs-debug-tree test.img
root tree
leaf 2539634688 items 16 free space 12515 generation 47 owner 1
fs uuid b1a70fc4-7c18-4929-9b73-8f8bb328e7de
chunk uuid c2606900-bfa1-444e-ab4d-3f0b2d31626b
item 0 key (EXTENT_TREE ROOT_ITEM 0) itemoff 15844 itemsize 439
root data bytenr 2539651072 level 0 dirid 0 refs 1 gen 47
uuid ----
item 1 key (DEV_TREE ROOT_ITEM 0) itemoff 15405 itemsize 439
root data bytenr 2539569152 level 0 dirid 0 refs 1 gen 46
uuid ----
item 2 key (FS_TREE INODE_REF 6) itemoff 15388 itemsize 17
inode ref index 0 namelen 7 name: default
item 3 key (FS_TREE ROOT_ITEM 0) itemoff 14949 itemsize 439
root data bytenr 2539356160 level 0 dirid 256 refs 1 gen 42
uuid ----
ctransid 6 otransid 0 stransid 0 rtransid 0
item 4 key (ROOT_TREE_DIR INODE_ITEM 0) itemoff 14789 itemsize 160
inode generation 3 transid 0 size 0 block group 0 mode 40755
links 1 uid 0 gid 0 rdev 0 flags 0x0
item 5 key (ROOT_TREE_DIR INODE_REF 6) itemoff 14777 itemsize 12
inode ref index 0 namelen 2 name: ..
item 6 key (ROOT_TREE_DIR DIR_ITEM 2378154706) itemoff 14740 itemsize 37
location key (FS_TREE ROOT_ITEM -1) type DIR
namelen 7 datalen 0 name: default
item 7 key (CSUM_TREE ROOT_ITEM 0) itemoff 14301 itemsize 439
root data bytenr 2539667456 level 0 dirid 0 refs 1 gen 47
uuid ----
item 8 key (UUID_TREE ROOT_ITEM 0) itemoff 13862 itemsize 439
root data bytenr 2539208704 level 0 dirid 0 refs 1 gen 41
uuid be2539ee-1c09-e84c-8ec9-bfe054347ccf
item
