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Re: [PATCH] ext2fs and large stores (> 1.5G)
From: |
Neal H. Walfield |
Subject: |
Re: [PATCH] ext2fs and large stores (> 1.5G) |
Date: |
02 May 2003 21:35:58 -0400 |
User-agent: |
Gnus/5.0808 (Gnus v5.8.8) Emacs/21.2 |
It seems your email client is broken, it does not respect my
Mail-Copies-To header.
> > Can you describe the problem you are having?
>
> disk_image_bptr vector maps block number to memory address. When I
> reuse block in the cache I make the new block to map to the same
> address. The bug was that the old block continued to map to the
> address, thus one memory page is pointed by two disk blocks in
> disk_image_bptr.
>
> Of course, the solution is to remove the mapping between the old block
> and the memory page. Unfortunately, some functions can think that
> this block is still in memory and expect valid pointer from boffs_ptr
> but they receive NULL.
Actually, it is worse than this, your locking is quite broken as it
only covers a few of many cases. Consider: a function can be using a
page and have it taken out from underneath it because use_count is
only used when the block is accessed via disk_image_request (and there
are a lot of places where you use, e.g. bptr directly). You need to
do reference counting on all blocks and it should be done via
boffs_ptr, bptr_offs et al., not disk_image_*. Consider,
record_global_poke for just one example. As far as I can tell,
disk_image_{request,release,clear} serve no purpose that should not be
in the bptr_*, boffs_* family of functions.
- Re: [PATCH] ext2fs and large stores (> 1.5G), Marcus Brinkmann, 2003/05/02
- Re: [PATCH] ext2fs and large stores (> 1.5G), Ognyan Kulev, 2003/05/02
- Re: [PATCH] ext2fs and large stores (> 1.5G), Neal H. Walfield, 2003/05/02
- Re: [PATCH] ext2fs and large stores (> 1.5G), Ognyan Kulev, 2003/05/02
- Re: [PATCH] ext2fs and large stores (> 1.5G),
Neal H. Walfield <=
- Re: [PATCH] ext2fs and large stores (> 1.5G), Yoshinori K. Okuji, 2003/05/03
- Re: [PATCH] ext2fs and large stores (> 1.5G), Simon Law, 2003/05/03
- Re: [PATCH] ext2fs and large stores (> 1.5G), Ognyan Kulev, 2003/05/03
- Re: [PATCH] ext2fs and large stores (> 1.5G), Neal H. Walfield, 2003/05/03
- Re: [PATCH] ext2fs and large stores (> 1.5G), Ognyan Kulev, 2003/05/04
- Re: [PATCH] ext2fs and large stores (> 1.5G), Neal H. Walfield, 2003/05/04
- Re: [PATCH] ext2fs and large stores (> 1.5G), Ognyan Kulev, 2003/05/04
- Re: [PATCH] ext2fs and large stores (> 1.5G), Neal H. Walfield, 2003/05/04
- Re: [PATCH] ext2fs and large stores (> 1.5G), Ognyan Kulev, 2003/05/05
- Re: [PATCH] ext2fs and large stores (> 1.5G), Marcus Brinkmann, 2003/05/05