Btrfs devel - Feb 2010 - [PATCH 0/2 V2] btrfs: a new tool to manage a btrfs filesystem

Hi all,

enclosed in the next two emails you can find two patches which introduce a new 
program called "btrfs". This program has the ambitious to replace the 
utilities of the btrfs-prog package, like:
- btrfsctl
- btrfs-show
- btrfs-volume
- btrfs

The goals are:
- improve the usability of the tools 
- add a man page which documents all the commands
- correct the btrfsctl return codes

I put a lot of attentions in order to avoid regression respect the old tools.
A clone of my git repository is available at

        http://cassiopea.homelinux.net/git/btrfs-command.git

On the basis of the feedback of the previous patches I rearranged some
"short
command name" (-s, -c ...) in order to avoid collision. I renamed also the 
command "create" in "subvolume" (and the relative short
command name from ''-S''
to ''-c'' :-) ).

Chris, do you think that these patches are mergeable ?

Comments are welcome.

BR
Goffredo
---

 Makefile       |    5
 btrfs.c        |  775 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/Makefile   |    5
 man/btrfs.8.in |  122 ++++++++
 4 files changed, 905 insertions(+), 2 deletions(-)

--

Example of use:
$ btrfs
Usage:
        btrfs snapshot|-s [<dest>/]<name>
                Create a writeble snapshot of the subvolume <source> with
                the name <name> in the <dest> directory.
        btrfs delete|-D <subvolume>
                Delete the subvolume <subvolume>.
        btrfs subvolume|-c [<dest>/]<name>
                Create a subvolume in <dest> (or the current directory if
                not passed).
        btrfs defrag|-f <file>|<dir> [<file>|<dir>...]
                Defragment a file or a directory.
        btrfs scan|-n [<device> [<device>..]
                Scan all device for or the passed device for a btrfs
                filesystem.
        btrfs fssync|-y <path>
                Force a fs sync on the filesystem <path>
        btrfs resize|-z [+/-]<newsize>[gkm]|max <filesystem>
                Resize the file system. If ''max'' is passed,
the filesystem
                will occupe all available space on the device.
        btrfs show|-l [<dev>|<label>...]
                Show the btrfs devices
        btrfs balance|-b <path>
                Balance the chunk across the device
        btrfs add-dev|-A <dev> [<dev>..] <path>
                Add a device to a filesystem
        btrfs rm-dev|-R <dev> [<dev>..] <path>
                Remove a device to a filesystem

        btrfs help|--help|-h
                Show the help.

Btrfs v0.19-12-g7e4c8e8-dirty




BTRFS(8)                             btrfs                            BTRFS(8)



NAME
       btrfs - control a btrfs filesystem

SYNOPSIS
       btrfs  snapshot|-s  <source> [<dest>/]<name>

       btrfs  delete|-D  <subvolume>

       btrfs  subvolume|-c  [<dest>/]<name>

       btrfs  defrag|-f  <file>|<dir> [<file>|<dir>...]

       btrfs  fssync|-y  <path>

       btrfs  resize|-z  [+/-]<size>[gkm]|max <filesystem>

       btrfs  scan|-n  [<device> [<device>..]]

       btrfs  show|-l  <dev>|<label> [<dev>|<label>...]

       btrfs  balance|-b  <path>

       btrfs  add-dev|-A  <dev> [<dev>..] <path>

       btrfs  rm-dev|-R  <dev> [<dev>..] <path> ]


       btrfs  help|--help|-h

DESCRIPTION
       btrfs  is  used to control the filesystem and the files and directories
       stored. It is the tool to create or destroy a new  snapshot  or  a  new
       subvolume for the filesystem, to defrag a file or a directory, to flush
       the dato to the disk, to resize the filesystem, to scan the device.    


OPTIONS
       snapshot|-s <source> [<dest>/]<name>
              Create a writeble snapshot of the subvolume  <source>  with 
the
              name  <name>  in the <dest> directory. If
<source> is not a sub‐
              volume, btrfs returns an error.                                 


       delete|-D <subvolume>
              Delete the subvolume <subvolume>. If <subvolume> is
not  a  sub‐
              volume, btrfs returns an error.                                 


       subvolume|-c [<dest>/]<name>
              Create  a  subvolume  in  <dest> (or in the current
directory if
              <dest> is not passed).


       defrag|-f <file>|<dir> [<file>|<dir>...]
              Defragment files and/or directories.


       scan|-n [<device> [<device>..]]
              Scan devices for a btrfs filesystem. If no devices  are  passed,
              btrfs scans all the block devices.                              


       fssync|-y <path>
              Force a sync for the filesystem identified by <path>.



       resize|-z [+/-]<size>[gkm]|max <filesystem>
              Resize a file system identified by <path>.  The <size>
parameter
              specifies the new size of the filesystem.  If the prefix + or  -
              is  present  the  size is increased or decreased by the quantity
              <size>.  If no units are  specified,  the  unit  of  the 
<size>
              parameter  is  the  byte.  Optionally, the size parameter may be
              suffixed by one of the following  the  units  designators: 
''K'',
              ''M'', or ''G'', kilobytes,
megabytes, or gigabytes, respectively.

              If  ''max''  is  passed,  the filesystem will
occupy all available
              space on the volume(s).                                         

              The resize command does not manipulate the  size  of  underlying
              partitions.   If  you  wish  to enlarge/reduce a filesystem, you
              must make sure you can expand/reduce the size of  the  partition
              also.                                                           


       show|-l [<dev>|<label>...]
              Show  the btrfs devices with some additional info. If no devices
              or labels are passed, btrfs scans all the block devices.


       balance|-b <path>
              Balance the chunk of the filesystem identified by <path> 
across
              the devices.


       add-dev|-A  <dev> [<dev>..] <path>
              Add device(s) to the filesystem identified by <path>.


       rm-dev|-R  <dev> [<dev>..] <path>
              Remove device(s) to the filesystem identified by <path>.

EXIT STATUS
       btrf  returns  a zero exist status if it succeeds. Non zero is returned
       in case of failure.


AVAILABILITY
       btrfs is part of btrfs-progs. Btrfs filesystem is currently under heavy
       development,  and not suitable for any uses other than benchmarking and
       review.  Please refer to the  btrfs  wiki  http://btrfs.wiki.kernel.org
       for further details.

SEE ALSO
       mkfs.btrfs(8)



btrfs                                                                 BTRFS(8)

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Hi,

Cool tool.
Just looking at the help output on the console I found a small typo.

Kind regards,
Andreas Philipp

diff --git a/btrfs.c b/btrfs.c
index cc55599..f3e5d8d 100644
--- a/btrfs.c
+++ b/btrfs.c
@@ -633,7 +633,7 @@ static struct Command commands[] = {
                "Add a device to a filesystem"
        },
        { -1, "rm-dev", "-R", "<dev>
[<dev>..] <path>\n"
-               "Remove a device to a filesystem"
+               "Remove a device from a filesystem"
        },
        /* coming soon
        { 2, "label", "-m", "<label>
<path>\n"


On 17.02.2010 21:02, Goffredo Baroncelli wrote:
> Hi all,
>
> enclosed in the next two emails you can find two patches which introduce a
new
> program called "btrfs". This program has the ambitious to replace
the
> utilities of the btrfs-prog package, like:
> - btrfsctl
> - btrfs-show
> - btrfs-volume
> - btrfs
>
> The goals are:
> - improve the usability of the tools 
> - add a man page which documents all the commands
> - correct the btrfsctl return codes
>
> I put a lot of attentions in order to avoid regression respect the old
tools.
> A clone of my git repository is available at
>
>         http://cassiopea.homelinux.net/git/btrfs-command.git
>
> On the basis of the feedback of the previous patches I rearranged some
"short
> command name" (-s, -c ...) in order to avoid collision. I renamed also
the
> command "create" in "subvolume" (and the relative short
command name from ''-S''
> to ''-c'' :-) ).
>
> Chris, do you think that these patches are mergeable ?
>
> Comments are welcome.
>
> BR
> Goffredo
> ---
>
>  Makefile       |    5
>  btrfs.c        |  775
+++++++++++++++++++++++++++++++++++++++++++++++++++++
>  man/Makefile   |    5
>  man/btrfs.8.in |  122 ++++++++
>  4 files changed, 905 insertions(+), 2 deletions(-)
>
> --
>
> Example of use:
> $ btrfs
> Usage:
>         btrfs snapshot|-s [<dest>/]<name>
>                 Create a writeble snapshot of the subvolume <source>
with
>                 the name <name> in the <dest> directory.
>         btrfs delete|-D <subvolume>
>                 Delete the subvolume <subvolume>.
>         btrfs subvolume|-c [<dest>/]<name>
>                 Create a subvolume in <dest> (or the current
directory if
>                 not passed).
>         btrfs defrag|-f <file>|<dir>
[<file>|<dir>...]
>                 Defragment a file or a directory.
>         btrfs scan|-n [<device> [<device>..]
>                 Scan all device for or the passed device for a btrfs
>                 filesystem.
>         btrfs fssync|-y <path>
>                 Force a fs sync on the filesystem <path>
>         btrfs resize|-z [+/-]<newsize>[gkm]|max <filesystem>
>                 Resize the file system. If ''max'' is
passed, the filesystem
>                 will occupe all available space on the device.
>         btrfs show|-l [<dev>|<label>...]
>                 Show the btrfs devices
>         btrfs balance|-b <path>
>                 Balance the chunk across the device
>         btrfs add-dev|-A <dev> [<dev>..] <path>
>                 Add a device to a filesystem
>         btrfs rm-dev|-R <dev> [<dev>..] <path>
>                 Remove a device to a filesystem
>
>         btrfs help|--help|-h
>                 Show the help.
>
> Btrfs v0.19-12-g7e4c8e8-dirty
>
>
>
>
> BTRFS(8)                             btrfs                           
BTRFS(8)
>
>
>
> NAME
>        btrfs - control a btrfs filesystem
>
> SYNOPSIS
>        btrfs  snapshot|-s  <source> [<dest>/]<name>
>
>        btrfs  delete|-D  <subvolume>
>
>        btrfs  subvolume|-c  [<dest>/]<name>
>
>        btrfs  defrag|-f  <file>|<dir>
[<file>|<dir>...]
>
>        btrfs  fssync|-y  <path>
>
>        btrfs  resize|-z  [+/-]<size>[gkm]|max <filesystem>
>
>        btrfs  scan|-n  [<device> [<device>..]]
>
>        btrfs  show|-l  <dev>|<label>
[<dev>|<label>...]
>
>        btrfs  balance|-b  <path>
>
>        btrfs  add-dev|-A  <dev> [<dev>..] <path>
>
>        btrfs  rm-dev|-R  <dev> [<dev>..] <path> ]
>
>
>        btrfs  help|--help|-h
>
> DESCRIPTION
>        btrfs  is  used to control the filesystem and the files and
directories
>        stored. It is the tool to create or destroy a new  snapshot  or  a 
new
>        subvolume for the filesystem, to defrag a file or a directory, to
flush
>        the dato to the disk, to resize the filesystem, to scan the device.
>
>
> OPTIONS
>        snapshot|-s <source> [<dest>/]<name>
>               Create a writeble snapshot of the subvolume  <source> 
with  the
>               name  <name>  in the <dest> directory. If
<source> is not a sub‐
>               volume, btrfs returns an error.
>
>
>        delete|-D <subvolume>
>               Delete the subvolume <subvolume>. If <subvolume>
is not  a  sub‐
>               volume, btrfs returns an error.
>
>
>        subvolume|-c [<dest>/]<name>
>               Create  a  subvolume  in  <dest> (or in the current
directory if
>               <dest> is not passed).
>
>
>        defrag|-f <file>|<dir> [<file>|<dir>...]
>               Defragment files and/or directories.
>
>
>        scan|-n [<device> [<device>..]]
>               Scan devices for a btrfs filesystem. If no devices  are 
passed,
>               btrfs scans all the block devices.
>
>
>        fssync|-y <path>
>               Force a sync for the filesystem identified by <path>.
>
>
>
>        resize|-z [+/-]<size>[gkm]|max <filesystem>
>               Resize a file system identified by <path>.  The
<size> parameter
>               specifies the new size of the filesystem.  If the prefix + or
-
>               is  present  the  size is increased or decreased by the
quantity
>               <size>.  If no units are  specified,  the  unit  of 
the  <size>
>               parameter  is  the  byte.  Optionally, the size parameter may
be
>               suffixed by one of the following  the  units  designators: 
''K'',
>               ''M'', or ''G'', kilobytes,
megabytes, or gigabytes, respectively.
>
>               If  ''max''  is  passed,  the filesystem will
occupy all available
>               space on the volume(s).
>
>               The resize command does not manipulate the  size  of 
underlying
>               partitions.   If  you  wish  to enlarge/reduce a filesystem,
you
>               must make sure you can expand/reduce the size of  the 
partition
>               also.
>
>
>        show|-l [<dev>|<label>...]
>               Show  the btrfs devices with some additional info. If no
devices
>               or labels are passed, btrfs scans all the block devices.
>
>
>        balance|-b <path>
>               Balance the chunk of the filesystem identified by
<path>  across
>               the devices.
>
>
>        add-dev|-A  <dev> [<dev>..] <path>
>               Add device(s) to the filesystem identified by <path>.
>
>
>        rm-dev|-R  <dev> [<dev>..] <path>
>               Remove device(s) to the filesystem identified by
<path>.
>
> EXIT STATUS
>        btrf  returns  a zero exist status if it succeeds. Non zero is
returned
>        in case of failure.
>
>
> AVAILABILITY
>        btrfs is part of btrfs-progs. Btrfs filesystem is currently under
heavy
>        development,  and not suitable for any uses other than benchmarking
and
>        review.  Please refer to the  btrfs  wiki 
http://btrfs.wiki.kernel.org
>        for further details.
>
> SEE ALSO
>        mkfs.btrfs(8)
>
>
>
> btrfs                                                                
BTRFS(8)
>
>   
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On Wednesday 17 February 2010, you (Andreas Philipp)
wrote:
> 
> Andreas Philipp <philipp.andreas@gmail.com>
Thank you, I corrected my source and updated the changes to the public 
repository.

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<kreijack@inwind.it>
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I think he need some command hierarchy here.

On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
<kreijack@gmail.com> wrote:
> OPTIONS
>       snapshot|-s <source> [<dest>/]<name>
>              Create a writeble snapshot of the subvolume  <source>
 with  the
>              name  <name>  in the <dest> directory. If
<source> is not a sub‐
>              volume, btrfs returns an error.
This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
It only works on subvolumes.
>
>
>       delete|-D <subvolume>
>              Delete the subvolume <subvolume>. If <subvolume>
is not  a  sub‐
>              volume, btrfs returns an error.
>
This becomes:

btrfs subvolume delete <subvolume>

This works with snapshots as well.
>
>       subvolume|-c [<dest>/]<name>
>              Create  a  subvolume  in  <dest> (or in the current
directory if
>              <dest> is not passed).
btrfs subvolume create [<dest>/]<name>
>
>
>       defrag|-f <file>|<dir> [<file>|<dir>...]
>              Defragment files and/or directories.
This will defrag individual files?  Does it defrag a directory tree?
Does it defrag a subvolume?  Does it defrag a pool?
>
>
>       scan|-n [<device> [<device>..]]
>              Scan devices for a btrfs filesystem. If no devices  are
 passed,
>              btrfs scans all the block devices.
btrfs pool scan [<device> [<device>..]]
>
>
>       fssync|-y <path>
>              Force a sync for the filesystem identified by <path>.
>
Does it sync a pool or subvolume?  Assuming it works against
subvolumes, it would be:

btrfs subvolume sync <path>
>
>
>       resize|-z [+/-]<size>[gkm]|max <filesystem>
>              Resize a file system identified by <path>.  The
<size> parameter
>              specifies the new size of the filesystem.  If the prefix + or
 -
>              is  present  the  size is increased or decreased by the
quantity
>              <size>.  If no units are  specified,  the  unit  of  the
 <size>
>              parameter  is  the  byte.  Optionally, the size parameter may
be
>              suffixed by one of the following  the  units  designators:
 ''K'',
>              ''M'', or ''G'', kilobytes,
megabytes, or gigabytes, respectively.
>
>              If  ''max''  is  passed,  the filesystem will
occupy all available
>              space on the volume(s).
>
>              The resize command does not manipulate the  size  of
 underlying
>              partitions.   If  you  wish  to enlarge/reduce a filesystem,
you
>              must make sure you can expand/reduce the size of  the
 partition
>              also.
>
This works with physical devices, not a pool or subvolume.  I get the
name "physical volume" from lvm.  Also I think it should resize to max
without arguments, in order to do that, the size argument would need
to be the last argument.

It becomes:

btrfs pvolume resize [+/-]<size>[gkm]|max <filesystem>

Or:

btrfs pvolume resize <filesystem> [[+/-]<size>[gkm]]
>
>       show|-l [<dev>|<label>...]
>              Show  the btrfs devices with some additional info. If no
devices
>              or labels are passed, btrfs scans all the block devices.
This becomes:

btrfs pool show [<dev>|<label>...]
>
>
>       balance|-b <path>
>              Balance the chunk of the filesystem identified by <path>
 across
>              the devices.
Is path to one of the block devices in the pool?

This becomes:

btrfs pool balance <path>
>
>
>       add-dev|-A  <dev> [<dev>..] <path>
>              Add device(s) to the filesystem identified by <path>.
What is path?  Somewhere the pool is mounted?  The root of where the
pool is mounted?

this becomes:

btrfs pvolume add <dev> [<dev>..] <path>
>
>
>       rm-dev|-R  <dev> [<dev>..] <path>
>              Remove device(s) to the filesystem identified by <path>.
(same questions as with add)

This becomes:

btrfs pvolume remove <dev> [<dev>..] <path>

Mike
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Hi,
I agree with Mike, it''s just much much more pleasant and intuitive to
work with the hierarchyial cli he suggests.

Alex
 
Mike Fedyk wrote:
> I think he need some command hierarchy here.
>
> On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
> <kreijack@gmail.com> wrote:
>   
>> OPTIONS
>>       snapshot|-s <source> [<dest>/]<name>
>>              Create a writeble snapshot of the subvolume 
<source>  with  the
>>              name  <name>  in the <dest> directory. If
<source> is not a sub‐
>>              volume, btrfs returns an error.
>>     
>
> This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
> It only works on subvolumes.
>
>   
>>       delete|-D <subvolume>
>>              Delete the subvolume <subvolume>. If
<subvolume> is not  a  sub‐
>>              volume, btrfs returns an error.
>>
>>     
>
> This becomes:
>
> btrfs subvolume delete <subvolume>
>
> This works with snapshots as well.
>
>   
>>       subvolume|-c [<dest>/]<name>
>>              Create  a  subvolume  in  <dest> (or in the current
directory if
>>              <dest> is not passed).
>>     
>
> btrfs subvolume create [<dest>/]<name>
>
>   
>>       defrag|-f <file>|<dir> [<file>|<dir>...]
>>              Defragment files and/or directories.
>>     
>
> This will defrag individual files?  Does it defrag a directory tree?
> Does it defrag a subvolume?  Does it defrag a pool?
>
>   
>>       scan|-n [<device> [<device>..]]
>>              Scan devices for a btrfs filesystem. If no devices  are 
passed,
>>              btrfs scans all the block devices.
>>     
>
> btrfs pool scan [<device> [<device>..]]
>
>   
>>       fssync|-y <path>
>>              Force a sync for the filesystem identified by
<path>.
>>
>>     
>
> Does it sync a pool or subvolume?  Assuming it works against
> subvolumes, it would be:
>
> btrfs subvolume sync <path>
>
>   
>>       resize|-z [+/-]<size>[gkm]|max <filesystem>
>>              Resize a file system identified by <path>.  The
<size> parameter
>>              specifies the new size of the filesystem.  If the prefix +
or  -
>>              is  present  the  size is increased or decreased by the
quantity
>>              <size>.  If no units are  specified,  the  unit  of 
the  <size>
>>              parameter  is  the  byte.  Optionally, the size parameter
may be
>>              suffixed by one of the following  the  units  designators:
''K'',
>>              ''M'', or ''G'',
kilobytes, megabytes, or gigabytes, respectively.
>>
>>              If  ''max''  is  passed,  the filesystem
will occupy all available
>>              space on the volume(s).
>>
>>              The resize command does not manipulate the  size  of 
underlying
>>              partitions.   If  you  wish  to enlarge/reduce a
filesystem, you
>>              must make sure you can expand/reduce the size of  the 
partition
>>              also.
>>
>>     
>
> This works with physical devices, not a pool or subvolume.  I get the
> name "physical volume" from lvm.  Also I think it should resize
to max
> without arguments, in order to do that, the size argument would need
> to be the last argument.
>
> It becomes:
>
> btrfs pvolume resize [+/-]<size>[gkm]|max <filesystem>
>
> Or:
>
> btrfs pvolume resize <filesystem> [[+/-]<size>[gkm]]
>
>   
>>       show|-l [<dev>|<label>...]
>>              Show  the btrfs devices with some additional info. If no
devices
>>              or labels are passed, btrfs scans all the block devices.
>>     
>
> This becomes:
>
> btrfs pool show [<dev>|<label>...]
>
>   
>>       balance|-b <path>
>>              Balance the chunk of the filesystem identified by
<path>  across
>>              the devices.
>>     
>
> Is path to one of the block devices in the pool?
>
> This becomes:
>
> btrfs pool balance <path>
>
>   
>>       add-dev|-A  <dev> [<dev>..] <path>
>>              Add device(s) to the filesystem identified by
<path>.
>>     
>
> What is path?  Somewhere the pool is mounted?  The root of where the
> pool is mounted?
>
> this becomes:
>
> btrfs pvolume add <dev> [<dev>..] <path>
>
>   
>>       rm-dev|-R  <dev> [<dev>..] <path>
>>              Remove device(s) to the filesystem identified by
<path>.
>>     
>
> (same questions as with add)
>
> This becomes:
>
> btrfs pvolume remove <dev> [<dev>..] <path>
>
> Mike
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I do like the subcommand method, more details below.

On Wed, Feb 17, 2010 at 03:35:26PM -0800, Mike Fedyk
wrote:
> I think he need some command hierarchy here.
> 
> On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
> <kreijack@gmail.com> wrote:
> > OPTIONS
> >       snapshot|-s <source> [<dest>/]<name>
> >              Create a writeble snapshot of the subvolume
 <source>  with  the
> >              name  <name>  in the <dest> directory. If
<source> is not a sub‐
> >              volume, btrfs returns an error.
> 
> This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
> It only works on subvolumes.
If we can type subvol instead of subvolume I like it.  Basically the
perl/python arg parsing system where any short form of the command that
uniquely matches it is allowed.

We keep the long forms but allow the user to pick a shorter form if it
isn''t ambiguous.
> 
> >
> >
> >       delete|-D <subvolume>
> >              Delete the subvolume <subvolume>. If
<subvolume> is not  a  sub‐
> >              volume, btrfs returns an error.
> >
> 
> This becomes:
> 
> btrfs subvolume delete <subvolume>
subvol del (same as above).
> 
> This works with snapshots as well.
> 
> >
> >       subvolume|-c [<dest>/]<name>
> >              Create  a  subvolume  in  <dest> (or in the current
directory if
> >              <dest> is not passed).
> 
> btrfs subvolume create [<dest>/]<name>
> 
> >
> >
> >       defrag|-f <file>|<dir> [<file>|<dir>...]
> >              Defragment files and/or directories.
> 
> This will defrag individual files?  Does it defrag a directory tree?
> Does it defrag a subvolume?  Does it defrag a pool?
For now lets change this to only do files.  That''s the only thing the
tool supports today.
> 
> >
> >
> >       scan|-n [<device> [<device>..]]
> >              Scan devices for a btrfs filesystem. If no devices  are
 passed,
> >              btrfs scans all the block devices.
> 
> btrfs pool scan [<device> [<device>..]]
Instead of btrfs pool, please use btrfs dev
> 
> >
> >
> >       fssync|-y <path>
> >              Force a sync for the filesystem identified by
<path>.
> >
> 
> Does it sync a pool or subvolume?  Assuming it works against
> subvolumes, it would be:
> 
> btrfs subvolume sync <path>
> 
> >
> >
> >       resize|-z [+/-]<size>[gkm]|max <filesystem>
> >              Resize a file system identified by <path>.  The
<size> parameter
> >              specifies the new size of the filesystem.  If the prefix
+ or  -
> >              is  present  the  size is increased or decreased by the
quantity
> >              <size>.  If no units are  specified,  the  unit  of
 the  <size>
> >              parameter  is  the  byte.  Optionally, the size parameter
may be
> >              suffixed by one of the following  the  units
 designators:  ''K'',
> >              ''M'', or ''G'',
kilobytes, megabytes, or gigabytes, respectively.
> >
> >              If  ''max''  is  passed,  the filesystem
will occupy all available
> >              space on the volume(s).
> >
> >              The resize command does not manipulate the  size  of
 underlying
> >              partitions.   If  you  wish  to enlarge/reduce a
filesystem, you
> >              must make sure you can expand/reduce the size of  the
 partition
> >              also.
> >
> 
> This works with physical devices, not a pool or subvolume.  I get the
> name "physical volume" from lvm.  Also I think it should resize
to max
> without arguments, in order to do that, the size argument would need
> to be the last argument.
We don''t have physical volumes and logical volumes the way lvm does, so
I''d like to avoid the pvolume theme.
> 
> It becomes:
> 
> btrfs pvolume resize [+/-]<size>[gkm]|max <filesystem>
> 
> Or:
> 
> btrfs pvolume resize <filesystem> [[+/-]<size>[gkm]]
btrfs dev resize
> 
> >
> >       show|-l [<dev>|<label>...]
> >              Show  the btrfs devices with some additional info. If no
devices
> >              or labels are passed, btrfs scans all the block devices.
> 
> This becomes:
> 
> btrfs pool show [<dev>|<label>...]
btrfs dev show
> 
> >
> >
> >       balance|-b <path>
> >              Balance the chunk of the filesystem identified by
<path>  across
> >              the devices.
> 
> Is path to one of the block devices in the pool?
> 
> This becomes:
> 
> btrfs pool balance <path>
btrfs dev balance
> 
> >
> >
> >       add-dev|-A  <dev> [<dev>..] <path>
> >              Add device(s) to the filesystem identified by
<path>.
> 
> What is path?  Somewhere the pool is mounted?  The root of where the
> pool is mounted?
The path just tells us which filesystem to work against.  It can really
be any path inside the mount point.
> 
> this becomes:
> 
> btrfs pvolume add <dev> [<dev>..] <path>
btrfs dev add 
> 
> >
> >
> >       rm-dev|-R  <dev> [<dev>..] <path>
> >              Remove device(s) to the filesystem identified by
<path>.
> 
> (same questions as with add)
> 
> This becomes:
> 
> btrfs pvolume remove <dev> [<dev>..] <path>
btrfs dev remove

-chris

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On Thu, Feb 18, 2010 at 8:58 AM, Chris Mason <chris.mason@oracle.com>
wrote:
> I do like the subcommand method, more details below.
>
> On Wed, Feb 17, 2010 at 03:35:26PM -0800, Mike Fedyk wrote:
>> I think he need some command hierarchy here.
>>
>> On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
>> <kreijack@gmail.com> wrote:
>> > OPTIONS
>> >       snapshot|-s <source> [<dest>/]<name>
>> >              Create a writeble snapshot of the subvolume
 <source>  with  the
>> >              name  <name>  in the <dest> directory. If
<source> is not a sub‐
>> >              volume, btrfs returns an error.
>>
>> This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
>> It only works on subvolumes.
>
> If we can type subvol instead of subvolume I like it.  Basically the
> perl/python arg parsing system where any short form of the command that
> uniquely matches it is allowed.
>
> We keep the long forms but allow the user to pick a shorter form if it
> isn''t ambiguous.
>
Yes, I agree.  This is why I compared it with the ip command which
does the same.
>>
>> >
>> >
>> >       delete|-D <subvolume>
>> >              Delete the subvolume <subvolume>. If
<subvolume> is not  a  sub‐
>> >              volume, btrfs returns an error.
>> >
>>
>> This becomes:
>>
>> btrfs subvolume delete <subvolume>
>
> subvol del (same as above).
>
>>
>> This works with snapshots as well.
>>
>> >
>> >       subvolume|-c [<dest>/]<name>
>> >              Create  a  subvolume  in  <dest> (or in the
current directory if
>> >              <dest> is not passed).
>>
>> btrfs subvolume create [<dest>/]<name>
>>
>> >
>> >
>> >       defrag|-f <file>|<dir>
[<file>|<dir>...]
>> >              Defragment files and/or directories.
>>
>> This will defrag individual files?  Does it defrag a directory tree?
>> Does it defrag a subvolume?  Does it defrag a pool?
>
> For now lets change this to only do files.  That''s the only thing
the
> tool supports today.
>
>>
>> >
>> >
>> >       scan|-n [<device> [<device>..]]
>> >              Scan devices for a btrfs filesystem. If no devices
 are  passed,
>> >              btrfs scans all the block devices.
>>
>> btrfs pool scan [<device> [<device>..]]
>
> Instead of btrfs pool, please use btrfs dev
>
>>
>> >
>> >
>> >       fssync|-y <path>
>> >              Force a sync for the filesystem identified by
<path>.
>> >
>>
>> Does it sync a pool or subvolume?  Assuming it works against
>> subvolumes, it would be:
>>
>> btrfs subvolume sync <path>
>>
>> >
>> >
>> >       resize|-z [+/-]<size>[gkm]|max <filesystem>
>> >              Resize a file system identified by <path>.  The
<size> parameter
>> >              specifies the new size of the filesystem.  If the
prefix + or  -
>> >              is  present  the  size is increased or decreased by
the quantity
>> >              <size>.  If no units are  specified,  the  unit
 of  the  <size>
>> >              parameter  is  the  byte.  Optionally, the size
parameter may be
>> >              suffixed by one of the following  the  units
 designators:  ''K'',
>> >              ''M'', or ''G'',
kilobytes, megabytes, or gigabytes, respectively.
>> >
>> >              If  ''max''  is  passed,  the
filesystem will occupy all available
>> >              space on the volume(s).
>> >
>> >              The resize command does not manipulate the  size  of
 underlying
>> >              partitions.   If  you  wish  to enlarge/reduce a
filesystem, you
>> >              must make sure you can expand/reduce the size of  the
 partition
>> >              also.
>> >
>>
>> This works with physical devices, not a pool or subvolume.  I get the
>> name "physical volume" from lvm.  Also I think it should
resize to max
>> without arguments, in order to do that, the size argument would need
>> to be the last argument.
>
> We don''t have physical volumes and logical volumes the way lvm
does, so
> I''d like to avoid the pvolume theme.
>
>>
>> It becomes:
>>
>> btrfs pvolume resize [+/-]<size>[gkm]|max <filesystem>
>>
>> Or:
>>
>> btrfs pvolume resize <filesystem> [[+/-]<size>[gkm]]
>
> btrfs dev resize
>
Dev works for me, I could only think of the lvm terms at the time.
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I''m happy that I''m not alone with my preference for
subcommands :) over short -<one-letter> commands.

Btw: I think it would be a good idea start from the beginning with a
''libbtrfs'' library and a corresponding API. That way
integrating into other languages like Python and integration into tools like
parted (or libparted) would be quite easy.


On 18 Feb 2010, at 18:58, Mike Fedyk wrote:
> On Thu, Feb 18, 2010 at 8:58 AM, Chris Mason <chris.mason@oracle.com>
wrote:
>> I do like the subcommand method, more details below.
>> 
>> On Wed, Feb 17, 2010 at 03:35:26PM -0800, Mike Fedyk wrote:
>>> I think he need some command hierarchy here.
>>> 
>>> On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
>>> <kreijack@gmail.com> wrote:
>>>> OPTIONS
>>>>       snapshot|-s <source> [<dest>/]<name>
>>>>              Create a writeble snapshot of the subvolume 
<source>  with  the
>>>>              name  <name>  in the <dest> directory.
If <source> is not a sub‐
>>>>              volume, btrfs returns an error.
>>> 
>>> This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
>>> It only works on subvolumes.
>> 
>> If we can type subvol instead of subvolume I like it.  Basically the
>> perl/python arg parsing system where any short form of the command that
>> uniquely matches it is allowed.
>> 
>> We keep the long forms but allow the user to pick a shorter form if it
>> isn''t ambiguous.
>> 
> 
> Yes, I agree.  This is why I compared it with the ip command which
> does the same.
> 
>>> 
>>>> 
>>>> 
>>>>       delete|-D <subvolume>
>>>>              Delete the subvolume <subvolume>. If
<subvolume> is not  a  sub‐
>>>>              volume, btrfs returns an error.
>>>> 
>>> 
>>> This becomes:
>>> 
>>> btrfs subvolume delete <subvolume>
>> 
>> subvol del (same as above).
>> 
>>> 
>>> This works with snapshots as well.
>>> 
>>>> 
>>>>       subvolume|-c [<dest>/]<name>
>>>>              Create  a  subvolume  in  <dest> (or in the
current directory if
>>>>              <dest> is not passed).
>>> 
>>> btrfs subvolume create [<dest>/]<name>
>>> 
>>>> 
>>>> 
>>>>       defrag|-f <file>|<dir>
[<file>|<dir>...]
>>>>              Defragment files and/or directories.
>>> 
>>> This will defrag individual files?  Does it defrag a directory
tree?
>>> Does it defrag a subvolume?  Does it defrag a pool?
>> 
>> For now lets change this to only do files.  That''s the only
thing the
>> tool supports today.
>> 
>>> 
>>>> 
>>>> 
>>>>       scan|-n [<device> [<device>..]]
>>>>              Scan devices for a btrfs filesystem. If no devices
are  passed,
>>>>              btrfs scans all the block devices.
>>> 
>>> btrfs pool scan [<device> [<device>..]]
>> 
>> Instead of btrfs pool, please use btrfs dev
>> 
>>> 
>>>> 
>>>> 
>>>>       fssync|-y <path>
>>>>              Force a sync for the filesystem identified by
<path>.
>>>> 
>>> 
>>> Does it sync a pool or subvolume?  Assuming it works against
>>> subvolumes, it would be:
>>> 
>>> btrfs subvolume sync <path>
>>> 
>>>> 
>>>> 
>>>>       resize|-z [+/-]<size>[gkm]|max <filesystem>
>>>>              Resize a file system identified by <path>. 
The <size> parameter
>>>>              specifies the new size of the filesystem.  If the
prefix + or  -
>>>>              is  present  the  size is increased or decreased
by the quantity
>>>>              <size>.  If no units are  specified,  the 
unit  of  the  <size>
>>>>              parameter  is  the  byte.  Optionally, the size
parameter may be
>>>>              suffixed by one of the following  the  units 
designators:  ''K'',
>>>>              ''M'', or ''G'',
kilobytes, megabytes, or gigabytes, respectively.
>>>> 
>>>>              If  ''max''  is  passed,  the
filesystem will occupy all available
>>>>              space on the volume(s).
>>>> 
>>>>              The resize command does not manipulate the  size 
of  underlying
>>>>              partitions.   If  you  wish  to enlarge/reduce a
filesystem, you
>>>>              must make sure you can expand/reduce the size of 
the  partition
>>>>              also.
>>>> 
>>> 
>>> This works with physical devices, not a pool or subvolume.  I get
the
>>> name "physical volume" from lvm.  Also I think it should
resize to max
>>> without arguments, in order to do that, the size argument would
need
>>> to be the last argument.
>> 
>> We don''t have physical volumes and logical volumes the way lvm
does, so
>> I''d like to avoid the pvolume theme.
>> 
>>> 
>>> It becomes:
>>> 
>>> btrfs pvolume resize [+/-]<size>[gkm]|max <filesystem>
>>> 
>>> Or:
>>> 
>>> btrfs pvolume resize <filesystem> [[+/-]<size>[gkm]]
>> 
>> btrfs dev resize
>> 
> 
> Dev works for me, I could only think of the lvm terms at the time.
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On Thursday 18 February 2010, Chris Mason wrote:
> I do like the subcommand method, more details below.
> 
I try to summarise your suggestions. But there are some cases not to clear for 
me. 
I grouped the commands in three categories: subvolume, devices, and 
filesystem.


devices 	scan
devices		show
devices		balance
devices		add
devices		remove

subvolume	snapshot
subvolume	delete
subvolume	create
[subvolume	list]

filesystem	resize
[filesystem	label]

??? 	defrag
???	sync



For the first two categories both Chris and Mike agreed; but IMHO there are 
some commands that don''t fit nor in devices, nor subvolume, like resize
(we
resize a filesystem) and label (not available now).

I don''t know how classify defrag (per file / directory level ?) and
sync
(filesystem ?)

An option is to consider commands without classification. For examples:

$ btrfs subvolume create [path/]<subvolname>
$ btrfs sync <path>
$ btrfs defrag <file>

Any comments and/or suggestions ?
> On Wed, Feb 17, 2010 at 03:35:26PM -0800, Mike Fedyk wrote:
> > I think he need some command hierarchy here.
> > 
> > On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
> > <kreijack@gmail.com> wrote:
> > > OPTIONS
> > >       snapshot|-s <source> [<dest>/]<name>
> > >              Create a writeble snapshot of the subvolume 
<source>  with
 the
> > >              name  <name>  in the <dest> directory.
If <source> is not a
sub‐
> > >              volume, btrfs returns an error.
> > 
> > This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
> > It only works on subvolumes.
> 
> If we can type subvol instead of subvolume I like it.  Basically the
> perl/python arg parsing system where any short form of the command that
> uniquely matches it is allowed.
> 
> We keep the long forms but allow the user to pick a shorter form if it
> isn''t ambiguous.
> 
> > 
> > >
> > >
> > >       delete|-D <subvolume>
> > >              Delete the subvolume <subvolume>. If
<subvolume> is not  a
 sub‐
> > >              volume, btrfs returns an error.
> > >
> > 
> > This becomes:
> > 
> > btrfs subvolume delete <subvolume>
> 
> subvol del (same as above).
> 
> > 
> > This works with snapshots as well.
> > 
> > >
> > >       subvolume|-c [<dest>/]<name>
> > >              Create  a  subvolume  in  <dest> (or in the
current
directory if
> > >              <dest> is not passed).
> > 
> > btrfs subvolume create [<dest>/]<name>
> > 
> > >
> > >
> > >       defrag|-f <file>|<dir>
[<file>|<dir>...]
> > >              Defragment files and/or directories.
> > 
> > This will defrag individual files?  Does it defrag a directory tree?
> > Does it defrag a subvolume?  Does it defrag a pool?
> 
> For now lets change this to only do files.  That''s the only thing
the
> tool supports today.
> 
> > 
> > >
> > >
> > >       scan|-n [<device> [<device>..]]
> > >              Scan devices for a btrfs filesystem. If no devices 
are
 passed,
> > >              btrfs scans all the block devices.
> > 
> > btrfs pool scan [<device> [<device>..]]
> 
> Instead of btrfs pool, please use btrfs dev
> 
> > 
> > >
> > >
> > >       fssync|-y <path>
> > >              Force a sync for the filesystem identified by
<path>.
> > >
> > 
> > Does it sync a pool or subvolume?  Assuming it works against
> > subvolumes, it would be:
> > 
> > btrfs subvolume sync <path>
> > 
> > >
> > >
> > >       resize|-z [+/-]<size>[gkm]|max <filesystem>
> > >              Resize a file system identified by <path>. 
The <size>
parameter
> > >              specifies the new size of the filesystem.  If the
prefix +
or  -
> > >              is  present  the  size is increased or decreased by
the
quantity
> > >              <size>.  If no units are  specified,  the 
unit  of  the
 <size>
> > >              parameter  is  the  byte.  Optionally, the size
parameter
may be
> > >              suffixed by one of the following  the  units 
designators:
 ''K'',
> > >              ''M'', or ''G'',
kilobytes, megabytes, or gigabytes,
respectively.
> > >
> > >              If  ''max''  is  passed,  the
filesystem will occupy all
available
> > >              space on the volume(s).
> > >
> > >              The resize command does not manipulate the  size  of
 underlying
> > >              partitions.   If  you  wish  to enlarge/reduce a 
filesystem, you
> > >              must make sure you can expand/reduce the size of 
the
 partition
> > >              also.
> > >
> > 
> > This works with physical devices, not a pool or subvolume.  I get the
> > name "physical volume" from lvm.  Also I think it should
resize to max
> > without arguments, in order to do that, the size argument would need
> > to be the last argument.
> 
> We don''t have physical volumes and logical volumes the way lvm
does, so
> I''d like to avoid the pvolume theme.
> 
> > 
> > It becomes:
> > 
> > btrfs pvolume resize [+/-]<size>[gkm]|max <filesystem>
> > 
> > Or:
> > 
> > btrfs pvolume resize <filesystem> [[+/-]<size>[gkm]]
> 
> btrfs dev resize
> 
> > 
> > >
> > >       show|-l [<dev>|<label>...]
> > >              Show  the btrfs devices with some additional info.
If no
devices
> > >              or labels are passed, btrfs scans all the block
devices.
> > 
> > This becomes:
> > 
> > btrfs pool show [<dev>|<label>...]
> 
> btrfs dev show
> 
> > 
> > >
> > >
> > >       balance|-b <path>
> > >              Balance the chunk of the filesystem identified by
<path>
 across
> > >              the devices.
> > 
> > Is path to one of the block devices in the pool?
> > 
> > This becomes:
> > 
> > btrfs pool balance <path>
> 
> btrfs dev balance
> 
> > 
> > >
> > >
> > >       add-dev|-A  <dev> [<dev>..] <path>
> > >              Add device(s) to the filesystem identified by
<path>.
> > 
> > What is path?  Somewhere the pool is mounted?  The root of where the
> > pool is mounted?
> 
> The path just tells us which filesystem to work against.  It can really
> be any path inside the mount point.
> 
> > 
> > this becomes:
> > 
> > btrfs pvolume add <dev> [<dev>..] <path>
> 
> btrfs dev add 
> > 
> > >
> > >
> > >       rm-dev|-R  <dev> [<dev>..] <path>
> > >              Remove device(s) to the filesystem identified by
<path>.
> > 
> > (same questions as with add)
> > 
> > This becomes:
> > 
> > btrfs pvolume remove <dev> [<dev>..] <path>
> 
> btrfs dev remove
> 
> -chris
> 
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On Thu, Feb 18, 2010 at 11:59 AM, Goffredo Baroncelli
<kreijack@gmail.com> wrote:
> On Thursday 18 February 2010, Chris Mason wrote:
>> I do like the subcommand method, more details below.
>>
>
> I try to summarise your suggestions. But there are some cases not to clear
for
> me.
> I grouped the commands in three categories: subvolume, devices, and
> filesystem.
>
>
> devices         scan
> devices         show
> devices         balance
> devices         add
> devices         remove
>
> subvolume       snapshot
> subvolume       delete
> subvolume       create
> [subvolume      list]
>
> filesystem      resize
> [filesystem     label]
>
> ???     defrag
> ???     sync
>
>
>
> For the first two categories both Chris and Mike agreed; but IMHO there are
> some commands that don''t fit nor in devices, nor subvolume, like
resize (we
> resize a filesystem) and label (not available now).
>
A btrfs filesystem can span multiple devices.  Resize resizes how big
of a chunk of one device btrfs uses.  This would be used by
partitioning programs for instance.  zfs uses the term "pool" instead
of filesystem to solve this ambiguous use of the term "filesystem"
since btrfs and zfs break people''s existing definition of the word
"filesystem".
> I don''t know how classify defrag (per file / directory level ?)
and sync
> (filesystem ?)
It turns out that defrag is per file, which seems most cumbersome.
Maybe since it will probably eventually work against several types of
objects we could have:

btrfs defrag file <file>
btrfs defrag directory <directory>
btrfs defrag subvol <subvol>
btrfs defrag pool <pool>
>
> An option is to consider commands without classification. For examples:
>
> $ btrfs subvolume create [path/]<subvolname>
> $ btrfs sync <path>
> $ btrfs defrag <file>
Maybe if the btrfs developers are agreeable, we could do this as well:

btrfs sync file <file>
btrfs sync directory <directory>
btrfs sync subvol <subvol>
btrfs sync pool <pool>

I''m not sure how useful syncing the pool or a directory tree would be,
but I''ll include it here for further discussion.

Mike
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On Thu, Feb 18, 2010 at 12:46:56PM -0800, Mike Fedyk
wrote:
> On Thu, Feb 18, 2010 at 11:59 AM, Goffredo Baroncelli
> <kreijack@gmail.com> wrote:
> > On Thursday 18 February 2010, Chris Mason wrote:
> >> I do like the subcommand method, more details below.
> >>
> >
> > I try to summarise your suggestions. But there are some cases not to
clear for
> > me.
> > I grouped the commands in three categories: subvolume, devices, and
> > filesystem.
> >
> >
> > devices         scan
> > devices         show
> > devices         balance
> > devices         add
> > devices         remove
> >
> > subvolume       snapshot
> > subvolume       delete
> > subvolume       create
> > [subvolume      list]
> >
> > filesystem      resize
> > [filesystem     label]
> >
> > ???     defrag
> > ???     sync
> >
> >
> >
> > For the first two categories both Chris and Mike agreed; but IMHO
there are
> > some commands that don''t fit nor in devices, nor subvolume,
like resize (we
> > resize a filesystem) and label (not available now).
> >
> 
> A btrfs filesystem can span multiple devices.  Resize resizes how big
> of a chunk of one device btrfs uses.
Right, resize is actually always per device.  When there is one device
resizing the FS and the device are the same thing.
> This would be used by
> partitioning programs for instance.  zfs uses the term "pool"
instead
> of filesystem to solve this ambiguous use of the term
"filesystem"
> since btrfs and zfs break people''s existing definition of the word
> "filesystem".
> 
> > I don''t know how classify defrag (per file / directory level
?) and sync
> > (filesystem ?)
> 
> It turns out that defrag is per file, which seems most cumbersome.
> Maybe since it will probably eventually work against several types of
> objects we could have:
> 
> btrfs defrag file <file>
> btrfs defrag directory <directory>
> btrfs defrag subvol <subvol>
I like these, although we don''t currently support the directory/subvol
side.  But we can leave the option open to add these later.
> btrfs defrag pool <pool>
I don''t think we''ll need defrag pool.
> 
> >
> > An option is to consider commands without classification. For
examples:
> >
> > $ btrfs subvolume create [path/]<subvolname>
> > $ btrfs sync <path>
> > $ btrfs defrag <file>
> 
> Maybe if the btrfs developers are agreeable, we could do this as well:
> 
> btrfs sync file <file>
> btrfs sync directory <directory>
fsync on files and dirs already does this, we don''t need a btrfsctl for
it.
> btrfs sync subvol <subvol>
btrfs sync subvol is nice.
> btrfs sync pool <pool>
> 
I don''t think we need sync pool.

-chris

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On Thursday 18 February 2010, Chris Mason wrote:
> I do like the subcommand method, more details below.
> 
> On Wed, Feb 17, 2010 at 03:35:26PM -0800, Mike Fedyk wrote:
> > I think he need some command hierarchy here.
> > 
> > On Wed, Feb 17, 2010 at 12:02 PM, Goffredo Baroncelli
> > <kreijack@gmail.com> wrote:
> > > OPTIONS
> > >       snapshot|-s <source> [<dest>/]<name>
> > >              Create a writeble snapshot of the subvolume 
<source>  with
 the
> > >              name  <name>  in the <dest> directory.
If <source> is not a
sub‐
> > >              volume, btrfs returns an error.
> > 
> > This should be "btrfs subvolume snapshot <source>
[<dest>/]<name>".
> > It only works on subvolumes.
> 
> If we can type subvol instead of subvolume I like it.  Basically the
> perl/python arg parsing system where any short form of the command that
> uniquely matches it is allowed.
So for you

$ btrfs s s <source> <dest>

is OK ?

(''btrfs s s'' means btrfs subvolume snapshot)


> We keep the long forms but allow the user to pick a shorter form if it
> isn''t ambiguous.
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On Thursday 18 February 2010, Chris Mason wrote:
> On Thu, Feb 18, 2010 at 12:46:56PM -0800, Mike Fedyk wrote:
> > On Thu, Feb 18, 2010 at 11:59 AM, Goffredo Baroncelli
> > <kreijack@gmail.com> wrote:
> > > On Thursday 18 February 2010, Chris Mason wrote:
> > >> I do like the subcommand method, more details below.
> > >>
> > >
> > > I try to summarise your suggestions. But there are some cases not
to
clear for
> > > me.
> > > I grouped the commands in three categories: subvolume, devices,
and
> > > filesystem.
> > >
> > >
> > > devices         scan
> > > devices         show
> > > devices         balance
> > > devices         add
> > > devices         remove
> > >
> > > subvolume       snapshot
> > > subvolume       delete
> > > subvolume       create
> > > [subvolume      list]
> > >
> > > filesystem      resize
> > > [filesystem     label]
> > >
> > > ???     defrag
> > > ???     sync
> > >
> > >
> > >
> > > For the first two categories both Chris and Mike agreed; but IMHO
there
are
> > > some commands that don''t fit nor in devices, nor
subvolume, like resize
(we
> > > resize a filesystem) and label (not available now).
> > >
> > 
> > A btrfs filesystem can span multiple devices.  Resize resizes how big
> > of a chunk of one device btrfs uses.
> 
> Right, resize is actually always per device.  When there is one device
> resizing the FS and the device are the same thing.
> 
> > This would be used by
> > partitioning programs for instance.  zfs uses the term
"pool" instead
> > of filesystem to solve this ambiguous use of the term
"filesystem"
> > since btrfs and zfs break people''s existing definition of the
word
> > "filesystem".
> > 
> > > I don''t know how classify defrag (per file / directory
level ?) and sync
> > > (filesystem ?)
> > 
> > It turns out that defrag is per file, which seems most cumbersome.
> > Maybe since it will probably eventually work against several types of
> > objects we could have:
> > 
> > btrfs defrag file <file>
> > btrfs defrag directory <directory>
> > btrfs defrag subvol <subvol>
> 
> I like these, although we don''t currently support the
directory/subvol
> side.  But we can leave the option open to add these later.
Sorry, but why:

	$ btrfs defrag subvol

and not 

	$ btrfs  subvol defrag

What do you want:

	$ btrfs <object> <action>

or

	$ btrfs <action> <object>


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<kreijack@inwind.it>
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On Thu, Feb 18, 2010 at 12:46:56PM -0800, Mike Fedyk
wrote:
> btrfs defrag file <file>
> btrfs defrag directory <directory>
> btrfs defrag subvol <subvol>
> btrfs defrag pool <pool>
  I think this could be implied by <target>, so it will be better to drop
3rd word:

btrfs defrag /this/file
btrfs defrag /mnt/btrfs/somedir/
btrfs defrag /dev/sda2  		# for pool
btrfs defrag LABEL="lnx-test"		# for pool; libblkid integration is
nice :)

-- 
Tomasz Torcz                 "God, root, what''s the
difference?"
xmpp: zdzichubg@chrome.pl         "God is more forgiving."

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On Thu, Feb 18, 2010 at 12:58 PM, Chris Mason <chris.mason@oracle.com>
wrote:
> On Thu, Feb 18, 2010 at 12:46:56PM -0800, Mike Fedyk wrote:
>> On Thu, Feb 18, 2010 at 11:59 AM, Goffredo Baroncelli
>> <kreijack@gmail.com> wrote:
>> > On Thursday 18 February 2010, Chris Mason wrote:
>> >> I do like the subcommand method, more details below.
>> >>
>> >
>> > I try to summarise your suggestions. But there are some cases not
to clear for
>> > me.
>> > I grouped the commands in three categories: subvolume, devices,
and
>> > filesystem.
>> >
>> >
>> > devices         scan
>> > devices         show
>> > devices         balance
>> > devices         add
>> > devices         remove
>> >
>> > subvolume       snapshot
>> > subvolume       delete
>> > subvolume       create
>> > [subvolume      list]
>> >
>> > filesystem      resize
>> > [filesystem     label]
>> >
>> > ???     defrag
>> > ???     sync
>> >
>> >
>> >
>> > For the first two categories both Chris and Mike agreed; but IMHO
there are
>> > some commands that don''t fit nor in devices, nor
subvolume, like resize (we
>> > resize a filesystem) and label (not available now).
>> >
>>
>> A btrfs filesystem can span multiple devices.  Resize resizes how big
>> of a chunk of one device btrfs uses.
>
> Right, resize is actually always per device.  When there is one device
> resizing the FS and the device are the same thing.
>
>> This would be used by
>> partitioning programs for instance.  zfs uses the term "pool"
instead
>> of filesystem to solve this ambiguous use of the term
"filesystem"
>> since btrfs and zfs break people''s existing definition of the
word
>> "filesystem".
>>
>> > I don''t know how classify defrag (per file / directory
level ?) and sync
>> > (filesystem ?)
>>
>> It turns out that defrag is per file, which seems most cumbersome.
>> Maybe since it will probably eventually work against several types of
>> objects we could have:
>>
>> btrfs defrag file <file>
>> btrfs defrag directory <directory>
>> btrfs defrag subvol <subvol>
>
> I like these, although we don''t currently support the
directory/subvol
> side.  But we can leave the option open to add these later.
>
>> btrfs defrag pool <pool>
>
> I don''t think we''ll need defrag pool.
>
>>
>> >
>> > An option is to consider commands without classification. For
examples:
>> >
>> > $ btrfs subvolume create [path/]<subvolname>
>> > $ btrfs sync <path>
>> > $ btrfs defrag <file>
>>
>> Maybe if the btrfs developers are agreeable, we could do this as well:
>>
>> btrfs sync file <file>
>> btrfs sync directory <directory>
>
> fsync on files and dirs already does this, we don''t need a
btrfsctl for
> it.
>
How do you fsync a file/dir from a shell script?  Maybe that''s a
generic tool that needs to be created...
>> btrfs sync subvol <subvol>
>
> btrfs sync subvol is nice.
>
>> btrfs sync pool <pool>
>>
>
> I don''t think we need sync pool.
>
I honestly can''t think of a use for it, but I''ll bet
it''ll come in
handy for some weird case while running on top of iscsi or some such
topology.
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