tree bd9b8570880cfda44a9fad7a2567b977ab53f631
parent 027d6404eb4327878454db72a006adfcb8001bb8
author Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> 1252226989 +0900
committer Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> 1252920433 +0900

nilfs2: always lookup disk block address before reading metadata block

The current metadata file code skips disk address lookup for its data
block if the buffer has a mapped flag.

This has a potential risk to cause read request to be performed
against the stale block address that GC moved, and it may lead to meta
data corruption.  The mapped flag is safe if the buffer has an
uptodate flag, otherwise it may prevent necessary update of disk
address in the next read.

This will avoid the potential problem by ensuring disk address lookup
before reading metadata block even for buffers with the mapped flag.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>