linux-kernel - bread problem

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Message-ID: <9ff7a3bc0908132152g694a2009r9007aed59428f892@mail.gmail.com>
Date:	Thu, 13 Aug 2009 21:52:59 -0700
From:	Joel Fernandes <agnel.joel@...il.com>
To:	linux-fs@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: bread problem

Hi,
I'm trying to read a block from disk by block_nr using __bread before
the block has even been written to disk.
The problem in doing this is the block is cached (junk data) and
future sb_bread's return the buffer head from this cache, and not one
that represent the actual data after this data has been written to
disk.

1. block contains junk
2. bread -> cached junk
3. actual data written to disk through the address space object hosted
by some other inode
4. bread -> still returns bh with junk

Is there any way to force a read from disk while doing the second
bread, or to instruct the kernel that the block that's in the cache
has to be re-read?

Thanks,
Joel
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