Messages in this thread | | | Date | Tue, 18 May 1999 15:31:33 -0400 (EDT) | From | "Theodore Y. Ts'o" <> | Subject | Re: ext2 question |
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Date: Tue, 18 May 1999 20:20:36 +0200 From: Manfred Spraul <manfreds@colorfullife.com>
No: use a mixed system: currently: the first 12 blocks direct, then 256 blocks indirect, then 65536 blocks indirect, etc. you replace the constants 12, 256 with 2 variables, everything else remains unchanged.
otherwise: clear 'extents possible', start a new block group (i.e. switch from direct to indirect or from indirect to double indirect); use the current system.
Oh, I see. Yes, that will will work, and it's pretty clever. In the worst case we might have a one or two extents in the inode before we get forced to swtich to an indirect scheme, but the direct extents describe less than 12 blocks you can convert the direct extents to direct blocks, and if it direct extents describe more than 12 blocks they were a win anyway.
Since the vast majority of files are written either sequentially, or with enough preallocation that the extent wouldn't be a problem, it's a nice solution.
I'll have to think about it some more, but off-hand that's a very interesting strategy.
- Ted
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