Re: Using UBIFS as an FTL

[Ezequiel Garcia <ezequiel.garcia@free-electrons.com>]

On 27 Jul 09:20 AM, Richard Weinberger wrote:
> On Sat, Jul 26, 2014 at 1:41 AM, hujianyang <hujianyang@huawei.com> wrote:
> > On 2014/7/26 2:21, Daniel Ehrenberg wrote:
> >> - loopback-mounting a file on ubifs--From skimming the code, it looks
> >> to me like ubifs uses some nice datastructures to handle writes within
> >> a file without doing read-modify-writes all the time as ubiblock
> >> forces. ubifs authors/maintainers, do you see any downside to using
> >> ubifs this way?
> >
> > This way seems most easily to realize. Synchronize the loop file and
> > maybe you will never worry about power cut.
> >
> > How about using UBI-layer and writing a new block driver to handle
> > bio? This driver should care about which leb on the flash has data
> > and other thing else(I don't have a clear idea now). The 'leb_change'
> > ops in UBI-layer maybe helpful for in-place update and atomic write.
> > But This way is harder than using a loop file.
> 
> Instead of adding another UBI block layer, please integrate such functionality
> in Ezequiel's UBI block.
> 

Daniel already mentioned it didn't git his needs. Quoting him:

"""
- ubiblock--the read-modify-write sounds unacceptable to me, even if
wear leveling and atomicity are handled.
- Some coworkers have suggested a new effort to build a new block
device, but that that's a huge project and takes a long time to get
right.
"""

Daniel: Maybe you can mention why you believe it's unacceptable?
-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com