tree 15f606a79b486170992719e1d290d36f61ae409a
parent 30ca22c70e3ef0a96ff84de69cd7e8561b416cb2
author Patrick J. LoPresti <lopresti@gmail.com> 1279836256 -0700
committer Joel Becker <joel.becker@oracle.com> 1284133314 -0700

JBD2: Allow feature checks before journal recovery

Before we start accessing a huge (> 16 TiB) OCFS2 volume, we need to
confirm that its journal supports 64-bit offsets.  In particular, we
need to check the journal's feature bits before recovering the journal.

This is not possible with JBD2 at present, because the journal
superblock (where the feature bits reside) is not loaded from disk until
the journal is recovered.

This patch loads the journal superblock in
jbd2_journal_check_used_features() if it has not already been loaded,
allowing us to check the feature bits before journal recovery.

Signed-off-by: Patrick LoPresti <lopresti@gmail.com>
Cc: linux-ext4@vger.kernel.org
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Joel Becker <joel.becker@oracle.com>