Messages in this thread |  | | | Date | Mon, 13 Sep 2010 16:09:05 -0700 | | From | Andrew Morton <> | | Subject | Re: [PATCH] vfs: calculate block-size correctly |
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On Wed, 8 Sep 2010 18:07:10 +0800 Cong Meng <mcpacino@gmail.com> wrote:
> I sent this patch half mount ago, but no response at all. If anything is > wrong, please tell me. Thanks a lots. This is my first time to send patch > to linux kernel. > > The invocation of __getblk(bdev, block, size) will cause kernel stall if > the @size parameter is not equal to the blockr-size of @bdev, which is saved > in bdev->bd_inode->i_blkbits. > > submit_bh() has the similar problem. > > This patch calculates the block-size using i_blkbits. > So that, for example, __getblk() can get a 4K buffer head while the > block-size of @bdev is 1K. >
This comes up every couple of years and iirc we always decided that it's a bug in the calling code somewhere. How did you hit it?
> --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -1051,10 +1051,7 @@ grow_buffers(struct block_device *bdev, sector_t block, int size) > pgoff_t index; > int sizebits; > > - sizebits = -1; > - do { > - sizebits++; > - } while ((size << sizebits) < PAGE_SIZE);
I'm sure the existing code could use __roundup_pow_of_two() here.
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