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Re: journal buffer_credits problem



> the 
> copy operation will eat up buffer credits from the current transaction. 
> ext3_prepare_write obviously does not reserve credits for us because it
> has 
> no idea that we intend to a whole lot more ext3 activity in between. I

Right.

> think 
> that for the most part, it so happens that the number of credits
> reserved in 
> ext3_prepare_write is conservatively quite high and we can squeeze in
> our 
> copy file without running out of credits, but sometimes we get unlucky
> and 
> there aren't enough credits for copying.
> As Erez said, we were nesting the copy operation between a prepare and 
> commit write. If instead, we do the copy before ext3_prepare_write and
> not 
> bother ext3 between ext3_prepare_write and ext3_commit_write, we don't
> run 
> into the
--buffer_credit problem, since the copy operation will happen in
> its 
> own transaction and will be allocated as many buffer credits as
> required.

You might need to nest the transaction as well.
What if power failure happen after backuping the file and before modify
to original file? Dp you left the backup file around?

Chris




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