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Commit 1c06b912 authored by Tristan Ye's avatar Tristan Ye
Browse files

Ocfs2/move_extents: find the victim alloc group, where the given #blk fits. 



This function tries locate the right alloc group, where a given physical block
resides, it returns the caller a buffer_head of victim group descriptor, and also
the offset of block in this group, by passing the block number.

Signed-off-by: default avatarTristan Ye <tristan.ye@oracle.com>
parent 202ee5fa

fs/ocfs2/move_extents.c

+104 −0
Original line number Diff line number Diff line
@@ -351,3 +351,107 @@ out: 


	return ret;

}



/*

 * find the victim alloc group, where #blkno fits.

 */

static int ocfs2_find_victim_alloc_group(struct inode *inode,

					 u64 vict_blkno,

					 int type, int slot,

					 int *vict_bit,

					 struct buffer_head **ret_bh)

{

	int ret, i, blocks_per_unit = 1;

	u64 blkno;

	char namebuf[40];



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

	struct buffer_head *ac_bh = NULL, *gd_bh = NULL;

	struct ocfs2_chain_list *cl;

	struct ocfs2_chain_rec *rec;

	struct ocfs2_dinode *ac_dinode;

	struct ocfs2_group_desc *bg;



	ocfs2_sprintf_system_inode_name(namebuf, sizeof(namebuf), type, slot);

	ret = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,

					 strlen(namebuf), &blkno);

	if (ret) {

		ret = -ENOENT;

		goto out;

	}



	ret = ocfs2_read_blocks_sync(osb, blkno, 1, &ac_bh);

	if (ret) {

		mlog_errno(ret);

		goto out;

	}



	ac_dinode = (struct ocfs2_dinode *)ac_bh->b_data;

	cl = &(ac_dinode->id2.i_chain);

	rec = &(cl->cl_recs[0]);



	if (type == GLOBAL_BITMAP_SYSTEM_INODE)

		blocks_per_unit <<= (osb->s_clustersize_bits -

						inode->i_sb->s_blocksize_bits);

	/*

	 * 'vict_blkno' was out of the valid range.

	 */

	if ((vict_blkno < le64_to_cpu(rec->c_blkno)) ||

	    (vict_blkno >= (le32_to_cpu(ac_dinode->id1.bitmap1.i_total) *

				blocks_per_unit))) {

		ret = -EINVAL;

		goto out;

	}



	for (i = 0; i < le16_to_cpu(cl->cl_next_free_rec); i++) {



		rec = &(cl->cl_recs[i]);

		if (!rec)

			continue;



		bg = NULL;



		do {

			if (!bg)

				blkno = le64_to_cpu(rec->c_blkno);

			else

				blkno = le64_to_cpu(bg->bg_next_group);



			if (gd_bh) {

				brelse(gd_bh);

				gd_bh = NULL;

			}



			ret = ocfs2_read_blocks_sync(osb, blkno, 1, &gd_bh);

			if (ret) {

				mlog_errno(ret);

				goto out;

			}



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



			if (vict_blkno < (le64_to_cpu(bg->bg_blkno) +

						le16_to_cpu(bg->bg_bits))) {



				*ret_bh = gd_bh;

				*vict_bit = (vict_blkno - blkno) /

							blocks_per_unit;

				mlog(0, "find the victim group: #%llu, "

				     "total_bits: %u, vict_bit: %u\n",

				     blkno, le16_to_cpu(bg->bg_bits),

				     *vict_bit);

				goto out;

			}



		} while (le64_to_cpu(bg->bg_next_group));

	}



	ret = -EINVAL;

out:

	brelse(ac_bh);



	/*

	 * caller has to release the gd_bh properly.

	 */

	return ret;

}