Re: [PATCH] mtd: cfi: Wait for Block Erase operation to finish

Paul Parsons
2012-03-02T15:15:16Z

--- On Fri, 2/3/12, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> > The problem only became a problem for me after I
> switched from JFFS2 to
> > UBIFS. I found that UBIFS would make file systems
> read-only. Either JFFS2
> > was more forgiving of CFI errors, or UBIFS exercised
> CFI in new ways that
> > provoked the errors. As others switch from JFFS2 to
> UBIFS they too might
> > find the same problem.
>
> yes, UBI probably has some different use. One seems that it
> keeps erasing the
> same block over and over again if the erase fails. JFFS2
> doesn't do that since
> you can't trust a block that is failing erase(how can you be
> sure that write will work?)
> So, IMHO, UBIFS should reconsider this policy.
>
> On that note, have you noticed any difference between JFFS2
> and UBIFS?
> Is performance comparable?

I haven't spent any time considering performance since I am preoccupied
with the errors. However my perception is that UBIFS boots slower but is
quicker for normal file writes and perhaps reads.

One functional difference which I have tested is the mmap(2) MAP_SHARED
flag. This was not supported in JFFS2 and consequently commands such as
localedef would simply fail. On UBIFS localedef works normally.