[RFC][V2] New attempt to a better "btrfs fi df"

[Goffredo Baroncelli <kreijack@gmail.com>]

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Hi all,

this is a new attempt to improve the output of the command "btrfs fi df".

The previous attempt received a good reception. However there was no a
general consensus about the wording.

Moreover I still didn't understand how btrfs was using the disks.
A my first attempt was to develop a new command which shows how the
disks are divided in chunks.
Then after some thoughts I made three commands:

$ btrfs filesystem df <path>
# btrfs device disk-usage <path>
# btrfs filesystem disk-usage <path>

The first one shows only the section that before I called "Summary":

$ ./btrfs filesystem df /mnt/btrfs1/
Disk_size:		  21.00GB
Disk_allocated:		   1.83GB
Disk_unallocated:	  19.17GB
Used:			 284.00KB
Free_(Estimated):	  15.76GB	(Max: 20.54GB, min: 10.96GB)
Data_to_disk_ratio:	     75 %

The second one show the chunk list grouped by devices:

$ sudo ./btrfs device disk-usage /mnt/btrfs1/
/dev/vdb	    3.00GB
   Data,Single:              8.00MB
   Data,RAID0:             307.25MB
   Metadata,Single:          8.00MB
   Metadata,RAID1:         460.94MB
   System,Single:            4.00MB
   Unallocated:              2.23GB

/dev/vdc	    3.00GB
   Data,RAID0:             307.25MB
   System,RAID1:             8.00MB
   Unallocated:              2.69GB

/dev/vdd	    3.00GB
   Data,RAID0:             307.25MB
   Metadata,RAID1:         460.94MB
   System,RAID1:             8.00MB
   Unallocated:              2.24GB

/dev/vdf	   12.00GB
   Unallocated:             12.00GB


The third one shows the devices grouped by chunk type; it has two kind
of output the first kind of output is a linear one (as before); the
second kind of output is in a tabular form. I don't like it because it
is suitable only when the filesystem uses few profile; otherwise this
output is larger than 80 columns.

$ sudo ./btrfs filesystem disk-usage /mnt/btrfs1/
Data,Single: Size:8.00MB, Used:0.00
   /dev/vdb	    8.00MB

Data,RAID0: Size:921.75MB, Used:256.00KB
   /dev/vdb	  307.25MB
   /dev/vdc	  307.25MB
   /dev/vdd	  307.25MB

Metadata,Single: Size:8.00MB, Used:0.00
   /dev/vdb	    8.00MB

Metadata,RAID1: Size:460.94MB, Used:24.00KB
   /dev/vdb	  460.94MB
   /dev/vdd	  460.94MB

System,Single: Size:4.00MB, Used:0.00
   /dev/vdb	    4.00MB

System,RAID1: Size:8.00MB, Used:4.00KB
   /dev/vdc	    8.00MB
   /dev/vdd	    8.00MB

Unallocated:
   /dev/vdb	    2.23GB
   /dev/vdc	    2.69GB
   /dev/vdd	    2.24GB
   /dev/vdf	   12.00GB



$ sudo ./btrfs filesystem disk-usage -t /mnt/btrfs1/
           Data      Data      Metadata  System    System
           Single    RAID0     Single    Single    RAID1     Unused

vdb          8.00MB  307.25MB    8.00MB    4.00MB         -    2.23GB
vdc               -  307.25MB         -         -    8.00MB    2.69GB
vdd               -  307.25MB         -         -    8.00MB    2.24GB
vdf               -         -         -         -         -   12.00GB
          ========= ========= ========= ========= ========= =========
Total        8.00MB  921.75MB    8.00MB    4.00MB    8.00MB   19.17GB
Used           0.00  256.00KB      0.00      0.00    4.00KB


The latest output is a fake, because the original one requires 78-79
columns, so the email reader would rewrap it. I had to remove a column
(Metadata,RAID1) : this confirm me that this kind of output is
unusable as general case.

The code is pullable from
        http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git
branch
        info-cmd

I don't publish the patches because aren't in a good shape. The
example is a filesystem based on three disks of 3GB and one disk of 12 GB.

Comments are welcome.

Known bugs:
- - the commands btrfs fi disk-usage and btrfs device disk-usage need
root capability (I use the BTRFS_IOC_TREE_SEARCH
to get the chunk info; so that is unavoidable)



- -- 
gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it>
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