Re: [ECOS] fseek on JFFS2

[Andrew Lunn <andrew at lunn dot ch>]

> set_position() calculates the new absolute position and calls 
> cyg_stdio_lseek() which (with CYGPKG_FILEIO) is meant to be just a thin 
> veneer over lseek().

fseek() works fine. However flush_output_unlocked() does not call
set_position() before flushing out the buffer. It seems to assume the
file position is already in the correct position. The test case shows
its not. What has happened is a read is made which fills the buffer
and obviously leaves the file pointer after the end of the data just
read. There is when a write within this buffer, which is naturally
buffered. The test case then does a fseek() back to the beginning of
the file. This causes the buffer to be flushed, which just causes it
to be written out. There is no set_position() called to seek back to
the start of the buffer location in the file, so the data gets written
in the wrong place. 

   Andrew

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