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

[Goffredo Baroncelli <kreijack@inwind.it>]

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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. However it still was no clear. Then I
realised that I need to merge the two output.

Below the results. It shows how the disks is used by the different chunks.

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

I don't publish the patched because aren't in a good shape. However I
really like the output. The example is a filesystem based on three
disks of 3GB.

It is clear that:
- - RAID0 uses all the disks
- - RAID1 uses two different disks

Comments are welcome.

Known bugs:
- - if a filesystem uses a disk but there is any chunk, the disk is not
shown (solvable)
- - this command need root capability (I use the BTRFS_IOC_TREE_SEARCH
to get the chunk info; so that is unavoidable)


ghigo@emulato:~$ sudo ./btrfs fi df /mnt/btrfs1/
[sudo] password for ghigo:
Path: /mnt/btrfs1
Summary:
  Disk_size:		   9.00GB
  Disk_allocated:	   1.83GB
  Disk_unallocated:	   7.17GB
  Used:			 284.00KB
  Free_(Estimated):	   6.76GB	(Max: 8.54GB, min: 4.96GB)
  Data_to_disk_ratio:	     75 %

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

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

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

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

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

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

  Unused:
     /dev/vdb	    2.23GB
     /dev/vdc	    2.69GB
     /dev/vdd	    2.24GB



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