Re: MPSAFE VFS -- List of upcoming actions

> On 07/17/2012 22:54, Gustau Pérez i Querol wrote:
>> In fact filesystems not particulary specific and not tied our kernel
>> would go to userspace; thinks like smbfs, nwfs, ntfs, ext2 o ext4 for
>> example should be in userspace

    The list is incomplete and maybe wrong; maybe some should stay in 
the kernel. It was just a quick guess. If you are think the list should 
be reviewed, I completely agree.

> A big -1 here.
>
> The more native FS support we have the better off we are in terms of
> both people migrating from other OS', and people who need to maintain
> compatibility with other OS'.

   Well, I don't think we would lose compatibility (but I may be wrong).

   I think there are some fs' too complex to implement or maintain, like 
the ntfs one. About the ntfs case there's a complete fs implementation 
of it in userspace. And there are also many other fs' implementations in 
userspace. I think we can benefit from those implementations, removing 
the burden of maintaining them in the kernel (it would have been useful 
to have it in userspace right now because of the vfs giant lock removal 
deadline).

   The fs' staying in the kernel should be well maintained, the others 
in userspace would always work too as long as fuse is up to date; if 
anything changes in the kernel only fuse would need to be fixed to allow 
the many fs' in userpace to work.

   In the final situation we would end having a few fs in the kernel (I 
don't exactly know which ones to keep) and then some in userspace that 
could be installed via ports. We wouldn't lose compatibility with other 
OS', I think instead we would have more compatibility because we could 
benefit from the implementation of many fs' in userspace.

    People migrating from other OS' would have the possibility of 
installing the appropriate fusefs port.

    Of course, I don't know the exact list of fs' staying and leaving.

>   Personally I use both msdosfs and ext2fs
> extensively for the latter purpose, and would not want to see either
> removed.

    Well, I don't know which ones I would remove/migrate to userspace. 
The msdosfs is probably one I wouldn't migrate.

    About the ext2 I used to use it time ago at work. Now I remember 
there was a GoC in 2009 to update the implementation and I would keep it 
in the kernel. We could even keep ext2 in the kernel and have support 
for it as a fusefs port; I could choose the kernel or the userspace 
implementation.

    At work I also have to deal with ext4 or exfat filesystems from time 
to time. Having a working fuse implementation would allow me to have a 
better compatibility with other OS'.


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O O O Gustau Pérez i Querol
O O O Departament d'Enginyeria Telemàtica
O O O Universitat Politècnica de Catalunya
       Edifici C3 - Despatx S101-B
  UPC  Campus Nord UPC
       C/ Jordi Girona, 1-3
       08034 - Barcelona