Re: block allocation in ext2fs

From: Benhanokh Gabriel (gabriel@SANgate.com)
Date: Wed May 10 2000 - 14:03:54 EST


> > i didn't see who is calling the end_that_request_last function, it is not being
> > called by the ll_rw_blk or the make_reqest functions
> > should i call it myself?
> not needed make_request will call it internally
> end_that_request_last is usually executed by the driver itself
> look in ide.c and associated files (it indicates completion of
> requests thus awaking all processes sleeping on request's wait
> queue)

> > ok, i checked it up and it looks like there is no need to override the
> > make_request function, it checks for the dirty bit before attemting to write, and
> > if it is clean it jumps directly to the end_io: label which calls the b_end_io
> > so i guess that using
> > mark_buffer_uptodate( bh )
> > mark_buffer_clean( bh )
> >
> > will prevent the buffer from being ever written to the disk.
> >
> Every true
> > but how do i recycle the buffer head? do i need to call brelease or bforget ? or
> call brelse takes care of all conditions and safe
> > that the make_request will take care for this ?
> no
> > do i need to call end_that_request_last ?
> no make_request internally calls it on completion of last buffer
> request

i think that if i mark the buffer_clean than make_request would never
issue any request, so there will be noone calling
end_that_request_last()

regards
/gaby

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