Re: [ECOS] blib node allocation problem with FAT FS

[Andrew Lunn <andrew at lunn dot ch>]

> I found the problem. The reference count was decrementing below 0. Here 
> is a fix for fatfs_node_unref() in fatfs_ncache.c.
>
>  if (node->refcnt)
>        node->refcnt--;

It could be that you have fixed the symptom and not the cause. Why is
it being unreferenced more times than it is referenced? Maybe there is
a missing ref() so you could get file corrupt?

Before i commit this i want a clear explanation why your change is
correct.

> I also found that if you change the 512 to 32768 (sector size) in fatfs.c 
> call to cyg_blib_io_create() you get a 50% - 60% increase in disk  
> throughput, especially with large files. (driver reads writes clusters 
> not sectors)

Which driver? I quickly looked at the IDE and the MMC driver and both
appear to read/write blocks.

There is a FIXME where the cyg_blib_io_create() is, saying to get the
block size from the device. Maybe you want to implement this?

      Andrew

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