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Commit 99e4c750 authored by Tristan Ye's avatar Tristan Ye
Browse files

Ocfs2/move_extents: helper to validate and adjust moving goal. 



First best-effort attempt to validate and adjust the goal (physical address in
block), while it can't guarantee later operation can succeed all the time since
global_bitmap may change a bit over time.

Signed-off-by: default avatarTristan Ye <tristan.ye@oracle.com>
parent 1c06b912

fs/ocfs2/move_extents.c

+61 −0
Original line number Original line Diff line number Diff line
@@ -455,3 +455,64 @@ out: 
	 */

	 */

	return ret;

	return ret;

}

}



/*

 * XXX: helper to validate and adjust moving goal.

 */

static int ocfs2_validate_and_adjust_move_goal(struct inode *inode,

					       struct ocfs2_move_extents *range)

{

	int ret, goal_bit = 0;



	struct buffer_head *gd_bh = NULL;

	struct ocfs2_group_desc *bg;

	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

	int c_to_b = 1 << (osb->s_clustersize_bits -

					inode->i_sb->s_blocksize_bits);



	/*

	 * validate goal sits within global_bitmap, and return the victim

	 * group desc

	 */

	ret = ocfs2_find_victim_alloc_group(inode, range->me_goal,

					    GLOBAL_BITMAP_SYSTEM_INODE,

					    OCFS2_INVALID_SLOT,

					    &goal_bit, &gd_bh);

	if (ret)

		goto out;



	bg = (struct ocfs2_group_desc *)gd_bh->b_data;



	/*

	 * make goal become cluster aligned.

	 */

	if (range->me_goal % c_to_b)

		range->me_goal = range->me_goal / c_to_b * c_to_b;



	/*

	 * moving goal is not allowd to start with a group desc blok(#0 blk)

	 * let's compromise to the latter cluster.

	 */

	if (range->me_goal == le64_to_cpu(bg->bg_blkno))

		range->me_goal += c_to_b;



	/*

	 * movement is not gonna cross two groups.

	 */

	if ((le16_to_cpu(bg->bg_bits) - goal_bit) * osb->s_clustersize <

								range->me_len) {

		ret = -EINVAL;

		goto out;

	}

	/*

	 * more exact validations/adjustments will be performed later during

	 * moving operation for each extent range.

	 */

	mlog(0, "extents get ready to be moved to #%llu block\n",

	     range->me_goal);



out:

	brelse(gd_bh);



	return ret;

}