Commit 1113e1b5 authored Jul 22, 2010 by Patrick J. LoPresti Committed by Joel Becker Sep 10, 2010

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>

parent 30ca22c7

fs/jbd2/journal.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1371,6 +1371,10 @@ int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,

		if (!compat && !ro && !incompat)
		return 1;
		/* Load journal superblock if it is not loaded yet. */
		if (journal->j_format_version == 0 &&
		journal_get_superblock(journal) != 0)
		return 0;
		if (journal->j_format_version == 1)
		return 0;

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