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Commit 3bdb8efd authored by Patrick J. LoPresti's avatar Patrick J. LoPresti Committed by Joel Becker
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OCFS2: Allow huge (> 16 TiB) volumes to mount 



The OCFS2 developers have already done all of the hard work to allow
volumes larger than 16 TiB.  But there is still a "sanity check" in
fs/ocfs2/super.c that prevents the mounting of such volumes, even when
the cluster size and journal options would allow it.

This patch replaces that sanity check with a more sophisticated one to
mount a huge volume provided that (a) it is addressable by the raw
word/address size of the system (borrowing a test from ext4); (b) the
volume is using JBD2; and (c) the JBD2_FEATURE_INCOMPAT_64BIT flag is
set on the journal.

I factored out the sanity check into its own function.  I also moved it
from ocfs2_initialize_super() down to ocfs2_check_volume(); any earlier,
and the journal will not have been initialized yet.

This patch is one of a pair, and it depends on the other ("JBD2: Allow
feature checks before journal recovery").

I have tested this patch on small volumes, huge volumes, and huge
volumes without 64-bit block support in the journal.  All of them appear
to work or to fail gracefully, as appropriate.

Signed-off-by: default avatarPatrick LoPresti <lopresti@gmail.com>
Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
parent 1113e1b5

fs/ocfs2/super.c

+46 −5
Original line number Diff line number Diff line
@@ -1990,6 +1990,36 @@ static int ocfs2_setup_osb_uuid(struct ocfs2_super *osb, const unsigned char *uu 
	return 0;

}



/* Make sure entire volume is addressable by our journal.  Requires

   osb_clusters_at_boot to be valid and for the journal to have been

   initialized by ocfs2_journal_init(). */

static int ocfs2_journal_addressable(struct ocfs2_super *osb)

{

	int status = 0;

	u64 max_block =

		ocfs2_clusters_to_blocks(osb->sb,

					 osb->osb_clusters_at_boot) - 1;



	/* 32-bit block number is always OK. */

	if (max_block <= (u32)~0ULL)

		goto out;



	/* Volume is "huge", so see if our journal is new enough to

	   support it. */

	if (!(OCFS2_HAS_COMPAT_FEATURE(osb->sb,

				       OCFS2_FEATURE_COMPAT_JBD2_SB) &&

	      jbd2_journal_check_used_features(osb->journal->j_journal, 0, 0,

					       JBD2_FEATURE_INCOMPAT_64BIT))) {

		mlog(ML_ERROR, "The journal cannot address the entire volume. "

		     "Enable the 'block64' journal option with tunefs.ocfs2");

		status = -EFBIG;

		goto out;

	}



 out:

	return status;

}



static int ocfs2_initialize_super(struct super_block *sb,

				  struct buffer_head *bh,

				  int sector_size,
@@ -2002,6 +2032,7 @@ static int ocfs2_initialize_super(struct super_block *sb, 
	struct ocfs2_journal *journal;

	__le32 uuid_net_key;

	struct ocfs2_super *osb;

	u64 total_blocks;



	mlog_entry_void();
@@ -2214,11 +2245,15 @@ static int ocfs2_initialize_super(struct super_block *sb, 
		goto bail;

	}



	if (ocfs2_clusters_to_blocks(osb->sb, le32_to_cpu(di->i_clusters) - 1)

	    > (u32)~0UL) {

		mlog(ML_ERROR, "Volume might try to write to blocks beyond "

		     "what jbd can address in 32 bits.\n");

		status = -EINVAL;

	total_blocks = ocfs2_clusters_to_blocks(osb->sb,

						le32_to_cpu(di->i_clusters));



	status = generic_check_addressable(osb->sb->s_blocksize_bits,

					   total_blocks);

	if (status) {

		mlog(ML_ERROR, "Volume too large "

		     "to mount safely on this system");

		status = -EFBIG;

		goto bail;

	}
@@ -2380,6 +2415,12 @@ static int ocfs2_check_volume(struct ocfs2_super *osb) 
		goto finally;

	}



	/* Now that journal has been initialized, check to make sure

	   entire volume is addressable. */

	status = ocfs2_journal_addressable(osb);

	if (status)

		goto finally;



	/* If the journal was unmounted cleanly then we don't want to

	 * recover anything. Otherwise, journal_load will do that

	 * dirty work for us :) */