fs/ocfs2/resize.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * resize.c
  *
  * volume resize.
  * Inspired by ext3/resize.c.
  *
  * Copyright (C) 2007 Oracle.  All rights reserved.
  */

 #include <linux/fs.h>
 #include <linux/types.h>

 #include <cluster/masklog.h>

 #include "ocfs2.h"

 #include "alloc.h"
 #include "dlmglue.h"
 #include "inode.h"
 #include "journal.h"
 #include "super.h"
 #include "sysfile.h"
 #include "uptodate.h"
 #include "ocfs2_trace.h"

 #include "buffer_head_io.h"
 #include "suballoc.h"
 #include "resize.h"

 /*
  * Check whether there are new backup superblocks exist
  * in the last group. If there are some, mark them or clear
  * them in the bitmap.
  *
  * Return how many backups we find in the last group.
  */
 static u16 ocfs2_calc_new_backup_super(struct inode *inode,
 				       struct ocfs2_group_desc *gd,
 				       u16 cl_cpg,
 				       u16 old_bg_clusters,
 				       int set)
 {
 	int i;
 	u16 backups = 0;
 	u32 cluster, lgd_cluster;
 	u64 blkno, gd_blkno, lgd_blkno = le64_to_cpu(gd->bg_blkno);

 	for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
 		blkno = ocfs2_backup_super_blkno(inode->i_sb, i);
 		cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno);

 		gd_blkno = ocfs2_which_cluster_group(inode, cluster);
 		if (gd_blkno < lgd_blkno)
 			continue;
 		else if (gd_blkno > lgd_blkno)
 			break;

 		/* check if already done backup super */
 		lgd_cluster = ocfs2_blocks_to_clusters(inode->i_sb, lgd_blkno);
 		lgd_cluster += old_bg_clusters;
 		if (lgd_cluster >= cluster)
 			continue;

 		if (set)
 			ocfs2_set_bit(cluster % cl_cpg,
 				      (unsigned long *)gd->bg_bitmap);
 		else
 			ocfs2_clear_bit(cluster % cl_cpg,
 					(unsigned long *)gd->bg_bitmap);
 		backups++;
 	}

 	return backups;
 }

 static int ocfs2_update_last_group_and_inode(handle_t *handle,
 					     struct inode *bm_inode,
 					     struct buffer_head *bm_bh,
 					     struct buffer_head *group_bh,
 					     u32 first_new_cluster,
 					     int new_clusters)
 {
 	int ret = 0;
 	struct ocfs2_super *osb = OCFS2_SB(bm_inode->i_sb);
 	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) bm_bh->b_data;
 	struct ocfs2_chain_list *cl = &fe->id2.i_chain;
 	struct ocfs2_chain_rec *cr;
 	struct ocfs2_group_desc *group;
 	u16 chain, num_bits, backups = 0;
 	u16 cl_bpc = le16_to_cpu(cl->cl_bpc);
 	u16 cl_cpg = le16_to_cpu(cl->cl_cpg);
 	u16 old_bg_clusters;
 	u16 contig_bits;
 	__le16 old_bg_contig_free_bits;

 	trace_ocfs2_update_last_group_and_inode(new_clusters,
 						first_new_cluster);

 	ret = ocfs2_journal_access_gd(handle, INODE_CACHE(bm_inode),
 				      group_bh, OCFS2_JOURNAL_ACCESS_WRITE);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out;
 	}

 	group = (struct ocfs2_group_desc *)group_bh->b_data;

 	old_bg_clusters = le16_to_cpu(group->bg_bits) / cl_bpc;
 	/* update the group first. */
 	num_bits = new_clusters * cl_bpc;
 	le16_add_cpu(&group->bg_bits, num_bits);
 	le16_add_cpu(&group->bg_free_bits_count, num_bits);

 	/*
 	 * check whether there are some new backup superblocks exist in
 	 * this group and update the group bitmap accordingly.
 	 */
 	if (OCFS2_HAS_COMPAT_FEATURE(osb->sb,
 				     OCFS2_FEATURE_COMPAT_BACKUP_SB)) {
 		backups = ocfs2_calc_new_backup_super(bm_inode,
 						     group,
 						     cl_cpg, old_bg_clusters, 1);
 		le16_add_cpu(&group->bg_free_bits_count, -1 * backups);
 	}

 	contig_bits = ocfs2_find_max_contig_free_bits(group->bg_bitmap,
 					le16_to_cpu(group->bg_bits), 0);
 	old_bg_contig_free_bits = group->bg_contig_free_bits;
 	group->bg_contig_free_bits = cpu_to_le16(contig_bits);

 	ocfs2_journal_dirty(handle, group_bh);

 	/* update the inode accordingly. */
 	ret = ocfs2_journal_access_di(handle, INODE_CACHE(bm_inode), bm_bh,
 				      OCFS2_JOURNAL_ACCESS_WRITE);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out_rollback;
 	}

 	chain = le16_to_cpu(group->bg_chain);
 	cr = (&cl->cl_recs[chain]);
 	le32_add_cpu(&cr->c_total, num_bits);
 	le32_add_cpu(&cr->c_free, num_bits);
 	le32_add_cpu(&fe->id1.bitmap1.i_total, num_bits);
 	le32_add_cpu(&fe->i_clusters, new_clusters);

 	if (backups) {
 		le32_add_cpu(&cr->c_free, -1 * backups);
 		le32_add_cpu(&fe->id1.bitmap1.i_used, backups);
 	}

 	spin_lock(&OCFS2_I(bm_inode)->ip_lock);
 	OCFS2_I(bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
 	le64_add_cpu(&fe->i_size, (u64)new_clusters << osb->s_clustersize_bits);
 	spin_unlock(&OCFS2_I(bm_inode)->ip_lock);
 	i_size_write(bm_inode, le64_to_cpu(fe->i_size));

 	ocfs2_journal_dirty(handle, bm_bh);

 out_rollback:
 	if (ret < 0) {
 		ocfs2_calc_new_backup_super(bm_inode,
 					    group,
 					    cl_cpg, old_bg_clusters, 0);
 		le16_add_cpu(&group->bg_free_bits_count, backups);
 		le16_add_cpu(&group->bg_bits, -1 * num_bits);
 		le16_add_cpu(&group->bg_free_bits_count, -1 * num_bits);
 		group->bg_contig_free_bits = old_bg_contig_free_bits;
 	}
 out:
 	if (ret)
 		mlog_errno(ret);
 	return ret;
 }

 static int update_backups(struct inode * inode, u32 clusters, char *data)
 {
 	int i, ret = 0;
 	u32 cluster;
 	u64 blkno;
 	struct buffer_head *backup = NULL;
 	struct ocfs2_dinode *backup_di = NULL;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

 	/* calculate the real backups we need to update. */
 	for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
 		blkno = ocfs2_backup_super_blkno(inode->i_sb, i);
 		cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
 		if (cluster >= clusters)
 			break;

 		ret = ocfs2_read_blocks_sync(osb, blkno, 1, &backup);
 		if (ret < 0) {
 			mlog_errno(ret);
 			break;
 		}

 		memcpy(backup->b_data, data, inode->i_sb->s_blocksize);

 		backup_di = (struct ocfs2_dinode *)backup->b_data;
 		backup_di->i_blkno = cpu_to_le64(blkno);

 		ret = ocfs2_write_super_or_backup(osb, backup);
 		brelse(backup);
 		backup = NULL;
 		if (ret < 0) {
 			mlog_errno(ret);
 			break;
 		}
 	}

 	return ret;
 }

 static void ocfs2_update_super_and_backups(struct inode *inode,
 					   int new_clusters)
 {
 	int ret;
 	u32 clusters = 0;
 	struct buffer_head *super_bh = NULL;
 	struct ocfs2_dinode *super_di = NULL;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

 	/*
 	 * update the superblock last.
 	 * It doesn't matter if the write failed.
 	 */
 	ret = ocfs2_read_blocks_sync(osb, OCFS2_SUPER_BLOCK_BLKNO, 1,
 				     &super_bh);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out;
 	}

 	super_di = (struct ocfs2_dinode *)super_bh->b_data;
 	le32_add_cpu(&super_di->i_clusters, new_clusters);
 	clusters = le32_to_cpu(super_di->i_clusters);

 	ret = ocfs2_write_super_or_backup(osb, super_bh);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out;
 	}

 	if (OCFS2_HAS_COMPAT_FEATURE(osb->sb, OCFS2_FEATURE_COMPAT_BACKUP_SB))
 		ret = update_backups(inode, clusters, super_bh->b_data);

 out:
 	brelse(super_bh);
 	if (ret)
 		printk(KERN_WARNING "ocfs2: Failed to update super blocks on %s"
 			" during fs resize. This condition is not fatal,"
 			" but fsck.ocfs2 should be run to fix it\n",
 			osb->dev_str);
 	return;
 }

 /*
  * Extend the filesystem to the new number of clusters specified.  This entry
  * point is only used to extend the current filesystem to the end of the last
  * existing group.
  */
 int ocfs2_group_extend(struct inode * inode, int new_clusters)
 {
 	int ret;
 	handle_t *handle;
 	struct buffer_head *main_bm_bh = NULL;
 	struct buffer_head *group_bh = NULL;
 	struct inode *main_bm_inode = NULL;
 	struct ocfs2_dinode *fe = NULL;
 	struct ocfs2_group_desc *group = NULL;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	u16 cl_bpc;
 	u32 first_new_cluster;
 	u64 lgd_blkno;

 	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 		return -EROFS;

 	if (new_clusters < 0)
 		return -EINVAL;
 	else if (new_clusters == 0)
 		return 0;

 	main_bm_inode = ocfs2_get_system_file_inode(osb,
 						    GLOBAL_BITMAP_SYSTEM_INODE,
 						    OCFS2_INVALID_SLOT);
 	if (!main_bm_inode) {
 		ret = -EINVAL;
 		mlog_errno(ret);
 		goto out;
 	}

 	inode_lock(main_bm_inode);

 	ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out_mutex;
 	}

 	fe = (struct ocfs2_dinode *)main_bm_bh->b_data;

 	/* main_bm_bh is validated by inode read inside ocfs2_inode_lock(),
 	 * so any corruption is a code bug. */
 	BUG_ON(!OCFS2_IS_VALID_DINODE(fe));

 	if (le16_to_cpu(fe->id2.i_chain.cl_cpg) !=
 		ocfs2_group_bitmap_size(osb->sb, 0,
 					osb->s_feature_incompat) * 8) {
 		mlog(ML_ERROR, "The disk is too old and small. "
 		     "Force to do offline resize.");
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	first_new_cluster = le32_to_cpu(fe->i_clusters);
 	lgd_blkno = ocfs2_which_cluster_group(main_bm_inode,
 					      first_new_cluster - 1);

 	ret = ocfs2_read_group_descriptor(main_bm_inode, fe, lgd_blkno,
 					  &group_bh);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out_unlock;
 	}
 	group = (struct ocfs2_group_desc *)group_bh->b_data;

 	cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
 	if (le16_to_cpu(group->bg_bits) / cl_bpc + new_clusters >
 		le16_to_cpu(fe->id2.i_chain.cl_cpg)) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}


 	trace_ocfs2_group_extend(
 	     (unsigned long long)le64_to_cpu(group->bg_blkno), new_clusters);

 	handle = ocfs2_start_trans(osb, OCFS2_GROUP_EXTEND_CREDITS);
 	if (IS_ERR(handle)) {
 		mlog_errno(PTR_ERR(handle));
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	/* update the last group descriptor and inode. */
 	ret = ocfs2_update_last_group_and_inode(handle, main_bm_inode,
 						main_bm_bh, group_bh,
 						first_new_cluster,
 						new_clusters);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
 	}

 	ocfs2_update_super_and_backups(main_bm_inode, new_clusters);

 out_commit:
 	ocfs2_commit_trans(osb, handle);
 out_unlock:
 	brelse(group_bh);
 	brelse(main_bm_bh);

 	ocfs2_inode_unlock(main_bm_inode, 1);

 out_mutex:
 	inode_unlock(main_bm_inode);
 	iput(main_bm_inode);

 out:
 	return ret;
 }

 static int ocfs2_check_new_group(struct inode *inode,
 				 struct ocfs2_dinode *di,
 				 struct ocfs2_new_group_input *input,
 				 struct buffer_head *group_bh)
 {
 	int ret;
 	struct ocfs2_group_desc *gd =
 		(struct ocfs2_group_desc *)group_bh->b_data;
 	u16 cl_bpc = le16_to_cpu(di->id2.i_chain.cl_bpc);

 	ret = ocfs2_check_group_descriptor(inode->i_sb, di, group_bh);
 	if (ret)
 		goto out;

 	ret = -EINVAL;
 	if (le16_to_cpu(gd->bg_chain) != input->chain)
 		mlog(ML_ERROR, "Group descriptor # %llu has bad chain %u "
 		     "while input has %u set.\n",
 		     (unsigned long long)le64_to_cpu(gd->bg_blkno),
 		     le16_to_cpu(gd->bg_chain), input->chain);
 	else if (le16_to_cpu(gd->bg_bits) != input->clusters * cl_bpc)
 		mlog(ML_ERROR, "Group descriptor # %llu has bit count %u but "
 		     "input has %u clusters set\n",
 		     (unsigned long long)le64_to_cpu(gd->bg_blkno),
 		     le16_to_cpu(gd->bg_bits), input->clusters);
 	else if (le16_to_cpu(gd->bg_free_bits_count) != input->frees * cl_bpc)
 		mlog(ML_ERROR, "Group descriptor # %llu has free bit count %u "
 		     "but it should have %u set\n",
 		     (unsigned long long)le64_to_cpu(gd->bg_blkno),
 		     le16_to_cpu(gd->bg_bits),
 		     input->frees * cl_bpc);
 	else
 		ret = 0;

 out:
 	return ret;
 }

 static int ocfs2_verify_group_and_input(struct inode *inode,
 					struct ocfs2_dinode *di,
 					struct ocfs2_new_group_input *input,
 					struct buffer_head *group_bh)
 {
 	u16 cl_count = le16_to_cpu(di->id2.i_chain.cl_count);
 	u16 cl_cpg = le16_to_cpu(di->id2.i_chain.cl_cpg);
 	u16 next_free = le16_to_cpu(di->id2.i_chain.cl_next_free_rec);
 	u32 cluster = ocfs2_blocks_to_clusters(inode->i_sb, input->group);
 	u32 total_clusters = le32_to_cpu(di->i_clusters);
 	int ret = -EINVAL;

 	if (cluster < total_clusters)
 		mlog(ML_ERROR, "add a group which is in the current volume.\n");
 	else if (input->chain >= cl_count)
 		mlog(ML_ERROR, "input chain exceeds the limit.\n");
 	else if (next_free != cl_count && next_free != input->chain)
 		mlog(ML_ERROR,
 		     "the add group should be in chain %u\n", next_free);
 	else if (total_clusters + input->clusters < total_clusters)
 		mlog(ML_ERROR, "add group's clusters overflow.\n");
 	else if (input->clusters > cl_cpg)
 		mlog(ML_ERROR, "the cluster exceeds the maximum of a group\n");
 	else if (input->frees > input->clusters)
 		mlog(ML_ERROR, "the free cluster exceeds the total clusters\n");
 	else if (total_clusters % cl_cpg != 0)
 		mlog(ML_ERROR,
 		     "the last group isn't full. Use group extend first.\n");
 	else if (input->group != ocfs2_which_cluster_group(inode, cluster))
 		mlog(ML_ERROR, "group blkno is invalid\n");
 	else if ((ret = ocfs2_check_new_group(inode, di, input, group_bh)))
 		mlog(ML_ERROR, "group descriptor check failed.\n");
 	else
 		ret = 0;

 	return ret;
 }

 /* Add a new group descriptor to global_bitmap. */
 int ocfs2_group_add(struct inode *inode, struct ocfs2_new_group_input *input)
 {
 	int ret;
 	handle_t *handle;
 	struct buffer_head *main_bm_bh = NULL;
 	struct inode *main_bm_inode = NULL;
 	struct ocfs2_dinode *fe = NULL;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	struct buffer_head *group_bh = NULL;
 	struct ocfs2_group_desc *group = NULL;
 	struct ocfs2_chain_list *cl;
 	struct ocfs2_chain_rec *cr;
 	u16 cl_bpc;
 	u64 bg_ptr;

 	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 		return -EROFS;

 	main_bm_inode = ocfs2_get_system_file_inode(osb,
 						    GLOBAL_BITMAP_SYSTEM_INODE,
 						    OCFS2_INVALID_SLOT);
 	if (!main_bm_inode) {
 		ret = -EINVAL;
 		mlog_errno(ret);
 		goto out;
 	}

 	inode_lock(main_bm_inode);

 	ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out_mutex;
 	}

 	fe = (struct ocfs2_dinode *)main_bm_bh->b_data;

 	if (le16_to_cpu(fe->id2.i_chain.cl_cpg) !=
 		ocfs2_group_bitmap_size(osb->sb, 0,
 					osb->s_feature_incompat) * 8) {
 		mlog(ML_ERROR, "The disk is too old and small."
 		     " Force to do offline resize.");
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	ret = ocfs2_read_blocks_sync(osb, input->group, 1, &group_bh);
 	if (ret < 0) {
 		mlog(ML_ERROR, "Can't read the group descriptor # %llu "
 		     "from the device.", (unsigned long long)input->group);
 		goto out_unlock;
 	}

 	ocfs2_set_new_buffer_uptodate(INODE_CACHE(inode), group_bh);

 	ret = ocfs2_verify_group_and_input(main_bm_inode, fe, input, group_bh);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_free_group_bh;
 	}

 	trace_ocfs2_group_add((unsigned long long)input->group,
 			       input->chain, input->clusters, input->frees);

 	handle = ocfs2_start_trans(osb, OCFS2_GROUP_ADD_CREDITS);
 	if (IS_ERR(handle)) {
 		mlog_errno(PTR_ERR(handle));
 		ret = -EINVAL;
 		goto out_free_group_bh;
 	}

 	cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
 	cl = &fe->id2.i_chain;
 	cr = &cl->cl_recs[input->chain];

 	ret = ocfs2_journal_access_gd(handle, INODE_CACHE(main_bm_inode),
 				      group_bh, OCFS2_JOURNAL_ACCESS_WRITE);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out_commit;
 	}

 	group = (struct ocfs2_group_desc *)group_bh->b_data;
 	bg_ptr = le64_to_cpu(group->bg_next_group);
 	group->bg_next_group = cr->c_blkno;
 	ocfs2_journal_dirty(handle, group_bh);

 	ret = ocfs2_journal_access_di(handle, INODE_CACHE(main_bm_inode),
 				      main_bm_bh, OCFS2_JOURNAL_ACCESS_WRITE);
 	if (ret < 0) {
 		group->bg_next_group = cpu_to_le64(bg_ptr);
 		mlog_errno(ret);
 		goto out_commit;
 	}

 	if (input->chain == le16_to_cpu(cl->cl_next_free_rec)) {
 		le16_add_cpu(&cl->cl_next_free_rec, 1);
 		memset(cr, 0, sizeof(struct ocfs2_chain_rec));
 	}

 	cr->c_blkno = cpu_to_le64(input->group);
 	le32_add_cpu(&cr->c_total, input->clusters * cl_bpc);
 	le32_add_cpu(&cr->c_free, input->frees * cl_bpc);

 	le32_add_cpu(&fe->id1.bitmap1.i_total, input->clusters *cl_bpc);
 	le32_add_cpu(&fe->id1.bitmap1.i_used,
 		     (input->clusters - input->frees) * cl_bpc);
 	le32_add_cpu(&fe->i_clusters, input->clusters);

 	ocfs2_journal_dirty(handle, main_bm_bh);

 	spin_lock(&OCFS2_I(main_bm_inode)->ip_lock);
 	OCFS2_I(main_bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
 	le64_add_cpu(&fe->i_size, (u64)input->clusters << osb->s_clustersize_bits);
 	spin_unlock(&OCFS2_I(main_bm_inode)->ip_lock);
 	i_size_write(main_bm_inode, le64_to_cpu(fe->i_size));

 	ocfs2_update_super_and_backups(main_bm_inode, input->clusters);

 out_commit:
 	ocfs2_commit_trans(osb, handle);

 out_free_group_bh:
 	if (ret < 0)
 		ocfs2_remove_from_cache(INODE_CACHE(inode), group_bh);
 	brelse(group_bh);

 out_unlock:
 	brelse(main_bm_bh);

 	ocfs2_inode_unlock(main_bm_inode, 1);

 out_mutex:
 	inode_unlock(main_bm_inode);
 	iput(main_bm_inode);

 out:
 	return ret;
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* resize.c
	*
	* volume resize.
	* Inspired by ext3/resize.c.
	*
	* Copyright (C) 2007 Oracle. All rights reserved.
	*/

	#include <linux/fs.h>
	#include <linux/types.h>

	#include <cluster/masklog.h>

	#include "ocfs2.h"

	#include "alloc.h"
	#include "dlmglue.h"
	#include "inode.h"
	#include "journal.h"
	#include "super.h"
	#include "sysfile.h"
	#include "uptodate.h"
	#include "ocfs2_trace.h"

	#include "buffer_head_io.h"
	#include "suballoc.h"
	#include "resize.h"

	/*
	* Check whether there are new backup superblocks exist
	* in the last group. If there are some, mark them or clear
	* them in the bitmap.
	*
	* Return how many backups we find in the last group.
	*/
	static u16 ocfs2_calc_new_backup_super(struct inode *inode,
	struct ocfs2_group_desc *gd,
	u16 cl_cpg,
	u16 old_bg_clusters,
	int set)
	{
	int i;
	u16 backups = 0;
	u32 cluster, lgd_cluster;
	u64 blkno, gd_blkno, lgd_blkno = le64_to_cpu(gd->bg_blkno);

	for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
	blkno = ocfs2_backup_super_blkno(inode->i_sb, i);
	cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno);

	gd_blkno = ocfs2_which_cluster_group(inode, cluster);
	if (gd_blkno < lgd_blkno)
	continue;
	else if (gd_blkno > lgd_blkno)
	break;

	/* check if already done backup super */
	lgd_cluster = ocfs2_blocks_to_clusters(inode->i_sb, lgd_blkno);
	lgd_cluster += old_bg_clusters;
	if (lgd_cluster >= cluster)
	continue;

	if (set)
	ocfs2_set_bit(cluster % cl_cpg,
	(unsigned long *)gd->bg_bitmap);
	else
	ocfs2_clear_bit(cluster % cl_cpg,
	(unsigned long *)gd->bg_bitmap);
	backups++;
	}

	return backups;
	}

	static int ocfs2_update_last_group_and_inode(handle_t *handle,
	struct inode *bm_inode,
	struct buffer_head *bm_bh,
	struct buffer_head *group_bh,
	u32 first_new_cluster,
	int new_clusters)
	{
	int ret = 0;
	struct ocfs2_super *osb = OCFS2_SB(bm_inode->i_sb);
	struct ocfs2_dinode fe = (struct ocfs2_dinode ) bm_bh->b_data;
	struct ocfs2_chain_list *cl = &fe->id2.i_chain;
	struct ocfs2_chain_rec *cr;
	struct ocfs2_group_desc *group;
	u16 chain, num_bits, backups = 0;
	u16 cl_bpc = le16_to_cpu(cl->cl_bpc);
	u16 cl_cpg = le16_to_cpu(cl->cl_cpg);
	u16 old_bg_clusters;
	u16 contig_bits;
	__le16 old_bg_contig_free_bits;

	trace_ocfs2_update_last_group_and_inode(new_clusters,
	first_new_cluster);

	ret = ocfs2_journal_access_gd(handle, INODE_CACHE(bm_inode),
	group_bh, OCFS2_JOURNAL_ACCESS_WRITE);
	if (ret < 0) {
	mlog_errno(ret);
	goto out;
	}

	group = (struct ocfs2_group_desc *)group_bh->b_data;

	old_bg_clusters = le16_to_cpu(group->bg_bits) / cl_bpc;
	/* update the group first. */
	num_bits = new_clusters * cl_bpc;
	le16_add_cpu(&group->bg_bits, num_bits);
	le16_add_cpu(&group->bg_free_bits_count, num_bits);

	/*
	* check whether there are some new backup superblocks exist in
	* this group and update the group bitmap accordingly.
	*/
	if (OCFS2_HAS_COMPAT_FEATURE(osb->sb,
	OCFS2_FEATURE_COMPAT_BACKUP_SB)) {
	backups = ocfs2_calc_new_backup_super(bm_inode,
	group,
	cl_cpg, old_bg_clusters, 1);
	le16_add_cpu(&group->bg_free_bits_count, -1 * backups);
	}

	contig_bits = ocfs2_find_max_contig_free_bits(group->bg_bitmap,
	le16_to_cpu(group->bg_bits), 0);
	old_bg_contig_free_bits = group->bg_contig_free_bits;
	group->bg_contig_free_bits = cpu_to_le16(contig_bits);

	ocfs2_journal_dirty(handle, group_bh);

	/* update the inode accordingly. */
	ret = ocfs2_journal_access_di(handle, INODE_CACHE(bm_inode), bm_bh,
	OCFS2_JOURNAL_ACCESS_WRITE);
	if (ret < 0) {
	mlog_errno(ret);
	goto out_rollback;
	}

	chain = le16_to_cpu(group->bg_chain);
	cr = (&cl->cl_recs[chain]);
	le32_add_cpu(&cr->c_total, num_bits);
	le32_add_cpu(&cr->c_free, num_bits);
	le32_add_cpu(&fe->id1.bitmap1.i_total, num_bits);
	le32_add_cpu(&fe->i_clusters, new_clusters);

	if (backups) {
	le32_add_cpu(&cr->c_free, -1 * backups);
	le32_add_cpu(&fe->id1.bitmap1.i_used, backups);
	}

	spin_lock(&OCFS2_I(bm_inode)->ip_lock);
	OCFS2_I(bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
	le64_add_cpu(&fe->i_size, (u64)new_clusters << osb->s_clustersize_bits);
	spin_unlock(&OCFS2_I(bm_inode)->ip_lock);
	i_size_write(bm_inode, le64_to_cpu(fe->i_size));

	ocfs2_journal_dirty(handle, bm_bh);

	out_rollback:
	if (ret < 0) {
	ocfs2_calc_new_backup_super(bm_inode,
	group,
	cl_cpg, old_bg_clusters, 0);
	le16_add_cpu(&group->bg_free_bits_count, backups);
	le16_add_cpu(&group->bg_bits, -1 * num_bits);
	le16_add_cpu(&group->bg_free_bits_count, -1 * num_bits);
	group->bg_contig_free_bits = old_bg_contig_free_bits;
	}
	out:
	if (ret)
	mlog_errno(ret);
	return ret;
	}

	static int update_backups(struct inode * inode, u32 clusters, char *data)
	{
	int i, ret = 0;
	u32 cluster;
	u64 blkno;
	struct buffer_head *backup = NULL;
	struct ocfs2_dinode *backup_di = NULL;
	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

	/* calculate the real backups we need to update. */
	for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
	blkno = ocfs2_backup_super_blkno(inode->i_sb, i);
	cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
	if (cluster >= clusters)
	break;

	ret = ocfs2_read_blocks_sync(osb, blkno, 1, &backup);
	if (ret < 0) {
	mlog_errno(ret);
	break;
	}

	memcpy(backup->b_data, data, inode->i_sb->s_blocksize);

	backup_di = (struct ocfs2_dinode *)backup->b_data;
	backup_di->i_blkno = cpu_to_le64(blkno);

	ret = ocfs2_write_super_or_backup(osb, backup);
	brelse(backup);
	backup = NULL;
	if (ret < 0) {
	mlog_errno(ret);
	break;
	}
	}

	return ret;
	}

	static void ocfs2_update_super_and_backups(struct inode *inode,
	int new_clusters)
	{
	int ret;
	u32 clusters = 0;
	struct buffer_head *super_bh = NULL;
	struct ocfs2_dinode *super_di = NULL;
	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

	/*
	* update the superblock last.
	* It doesn't matter if the write failed.
	*/
	ret = ocfs2_read_blocks_sync(osb, OCFS2_SUPER_BLOCK_BLKNO, 1,
	&super_bh);
	if (ret < 0) {
	mlog_errno(ret);
	goto out;
	}

	super_di = (struct ocfs2_dinode *)super_bh->b_data;
	le32_add_cpu(&super_di->i_clusters, new_clusters);
	clusters = le32_to_cpu(super_di->i_clusters);

	ret = ocfs2_write_super_or_backup(osb, super_bh);
	if (ret < 0) {
	mlog_errno(ret);
	goto out;
	}

	if (OCFS2_HAS_COMPAT_FEATURE(osb->sb, OCFS2_FEATURE_COMPAT_BACKUP_SB))
	ret = update_backups(inode, clusters, super_bh->b_data);

	out:
	brelse(super_bh);
	if (ret)
	printk(KERN_WARNING "ocfs2: Failed to update super blocks on %s"
	" during fs resize. This condition is not fatal,"
	" but fsck.ocfs2 should be run to fix it\n",
	osb->dev_str);
	return;
	}

	/*
	* Extend the filesystem to the new number of clusters specified. This entry
	* point is only used to extend the current filesystem to the end of the last
	* existing group.
	*/
	int ocfs2_group_extend(struct inode * inode, int new_clusters)
	{
	int ret;
	handle_t *handle;
	struct buffer_head *main_bm_bh = NULL;
	struct buffer_head *group_bh = NULL;
	struct inode *main_bm_inode = NULL;
	struct ocfs2_dinode *fe = NULL;
	struct ocfs2_group_desc *group = NULL;
	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	u16 cl_bpc;
	u32 first_new_cluster;
	u64 lgd_blkno;

	if (ocfs2_is_hard_readonly(osb) \|\| ocfs2_is_soft_readonly(osb))
	return -EROFS;

	if (new_clusters < 0)
	return -EINVAL;
	else if (new_clusters == 0)
	return 0;

	main_bm_inode = ocfs2_get_system_file_inode(osb,
	GLOBAL_BITMAP_SYSTEM_INODE,
	OCFS2_INVALID_SLOT);
	if (!main_bm_inode) {
	ret = -EINVAL;
	mlog_errno(ret);
	goto out;
	}

	inode_lock(main_bm_inode);

	ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
	if (ret < 0) {
	mlog_errno(ret);
	goto out_mutex;
	}

	fe = (struct ocfs2_dinode *)main_bm_bh->b_data;

	/* main_bm_bh is validated by inode read inside ocfs2_inode_lock(),
	* so any corruption is a code bug. */
	BUG_ON(!OCFS2_IS_VALID_DINODE(fe));

	if (le16_to_cpu(fe->id2.i_chain.cl_cpg) !=
	ocfs2_group_bitmap_size(osb->sb, 0,
	osb->s_feature_incompat) * 8) {
	mlog(ML_ERROR, "The disk is too old and small. "
	"Force to do offline resize.");
	ret = -EINVAL;
	goto out_unlock;
	}

	first_new_cluster = le32_to_cpu(fe->i_clusters);
	lgd_blkno = ocfs2_which_cluster_group(main_bm_inode,
	first_new_cluster - 1);

	ret = ocfs2_read_group_descriptor(main_bm_inode, fe, lgd_blkno,
	&group_bh);
	if (ret < 0) {
	mlog_errno(ret);
	goto out_unlock;
	}
	group = (struct ocfs2_group_desc *)group_bh->b_data;

	cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
	if (le16_to_cpu(group->bg_bits) / cl_bpc + new_clusters >
	le16_to_cpu(fe->id2.i_chain.cl_cpg)) {
	ret = -EINVAL;
	goto out_unlock;
	}


	trace_ocfs2_group_extend(
	(unsigned long long)le64_to_cpu(group->bg_blkno), new_clusters);

	handle = ocfs2_start_trans(osb, OCFS2_GROUP_EXTEND_CREDITS);
	if (IS_ERR(handle)) {
	mlog_errno(PTR_ERR(handle));
	ret = -EINVAL;
	goto out_unlock;
	}

	/* update the last group descriptor and inode. */
	ret = ocfs2_update_last_group_and_inode(handle, main_bm_inode,
	main_bm_bh, group_bh,
	first_new_cluster,
	new_clusters);
	if (ret) {
	mlog_errno(ret);
	goto out_commit;
	}

	ocfs2_update_super_and_backups(main_bm_inode, new_clusters);

	out_commit:
	ocfs2_commit_trans(osb, handle);
	out_unlock:
	brelse(group_bh);
	brelse(main_bm_bh);

	ocfs2_inode_unlock(main_bm_inode, 1);

	out_mutex:
	inode_unlock(main_bm_inode);
	iput(main_bm_inode);

	out:
	return ret;
	}

	static int ocfs2_check_new_group(struct inode *inode,
	struct ocfs2_dinode *di,
	struct ocfs2_new_group_input *input,
	struct buffer_head *group_bh)
	{
	int ret;
	struct ocfs2_group_desc *gd =
	(struct ocfs2_group_desc *)group_bh->b_data;
	u16 cl_bpc = le16_to_cpu(di->id2.i_chain.cl_bpc);

	ret = ocfs2_check_group_descriptor(inode->i_sb, di, group_bh);
	if (ret)
	goto out;

	ret = -EINVAL;
	if (le16_to_cpu(gd->bg_chain) != input->chain)
	mlog(ML_ERROR, "Group descriptor # %llu has bad chain %u "
	"while input has %u set.\n",
	(unsigned long long)le64_to_cpu(gd->bg_blkno),
	le16_to_cpu(gd->bg_chain), input->chain);
	else if (le16_to_cpu(gd->bg_bits) != input->clusters * cl_bpc)
	mlog(ML_ERROR, "Group descriptor # %llu has bit count %u but "
	"input has %u clusters set\n",
	(unsigned long long)le64_to_cpu(gd->bg_blkno),
	le16_to_cpu(gd->bg_bits), input->clusters);
	else if (le16_to_cpu(gd->bg_free_bits_count) != input->frees * cl_bpc)
	mlog(ML_ERROR, "Group descriptor # %llu has free bit count %u "
	"but it should have %u set\n",
	(unsigned long long)le64_to_cpu(gd->bg_blkno),
	le16_to_cpu(gd->bg_bits),
	input->frees * cl_bpc);
	else
	ret = 0;

	out:
	return ret;
	}

	static int ocfs2_verify_group_and_input(struct inode *inode,
	struct ocfs2_dinode *di,
	struct ocfs2_new_group_input *input,
	struct buffer_head *group_bh)
	{
	u16 cl_count = le16_to_cpu(di->id2.i_chain.cl_count);
	u16 cl_cpg = le16_to_cpu(di->id2.i_chain.cl_cpg);
	u16 next_free = le16_to_cpu(di->id2.i_chain.cl_next_free_rec);
	u32 cluster = ocfs2_blocks_to_clusters(inode->i_sb, input->group);
	u32 total_clusters = le32_to_cpu(di->i_clusters);
	int ret = -EINVAL;

	if (cluster < total_clusters)
	mlog(ML_ERROR, "add a group which is in the current volume.\n");
	else if (input->chain >= cl_count)
	mlog(ML_ERROR, "input chain exceeds the limit.\n");
	else if (next_free != cl_count && next_free != input->chain)
	mlog(ML_ERROR,
	"the add group should be in chain %u\n", next_free);
	else if (total_clusters + input->clusters < total_clusters)
	mlog(ML_ERROR, "add group's clusters overflow.\n");
	else if (input->clusters > cl_cpg)
	mlog(ML_ERROR, "the cluster exceeds the maximum of a group\n");
	else if (input->frees > input->clusters)
	mlog(ML_ERROR, "the free cluster exceeds the total clusters\n");
	else if (total_clusters % cl_cpg != 0)
	mlog(ML_ERROR,
	"the last group isn't full. Use group extend first.\n");
	else if (input->group != ocfs2_which_cluster_group(inode, cluster))
	mlog(ML_ERROR, "group blkno is invalid\n");
	else if ((ret = ocfs2_check_new_group(inode, di, input, group_bh)))
	mlog(ML_ERROR, "group descriptor check failed.\n");
	else
	ret = 0;

	return ret;
	}

	/* Add a new group descriptor to global_bitmap. */
	int ocfs2_group_add(struct inode inode, struct ocfs2_new_group_input input)
	{
	int ret;
	handle_t *handle;
	struct buffer_head *main_bm_bh = NULL;
	struct inode *main_bm_inode = NULL;
	struct ocfs2_dinode *fe = NULL;
	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	struct buffer_head *group_bh = NULL;
	struct ocfs2_group_desc *group = NULL;
	struct ocfs2_chain_list *cl;
	struct ocfs2_chain_rec *cr;
	u16 cl_bpc;
	u64 bg_ptr;

	if (ocfs2_is_hard_readonly(osb) \|\| ocfs2_is_soft_readonly(osb))
	return -EROFS;

	main_bm_inode = ocfs2_get_system_file_inode(osb,
	GLOBAL_BITMAP_SYSTEM_INODE,
	OCFS2_INVALID_SLOT);
	if (!main_bm_inode) {
	ret = -EINVAL;
	mlog_errno(ret);
	goto out;
	}

	inode_lock(main_bm_inode);

	ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
	if (ret < 0) {
	mlog_errno(ret);
	goto out_mutex;
	}

	fe = (struct ocfs2_dinode *)main_bm_bh->b_data;

	if (le16_to_cpu(fe->id2.i_chain.cl_cpg) !=
	ocfs2_group_bitmap_size(osb->sb, 0,
	osb->s_feature_incompat) * 8) {
	mlog(ML_ERROR, "The disk is too old and small."
	" Force to do offline resize.");
	ret = -EINVAL;
	goto out_unlock;
	}

	ret = ocfs2_read_blocks_sync(osb, input->group, 1, &group_bh);
	if (ret < 0) {
	mlog(ML_ERROR, "Can't read the group descriptor # %llu "
	"from the device.", (unsigned long long)input->group);
	goto out_unlock;
	}

	ocfs2_set_new_buffer_uptodate(INODE_CACHE(inode), group_bh);

	ret = ocfs2_verify_group_and_input(main_bm_inode, fe, input, group_bh);
	if (ret) {
	mlog_errno(ret);
	goto out_free_group_bh;
	}

	trace_ocfs2_group_add((unsigned long long)input->group,
	input->chain, input->clusters, input->frees);

	handle = ocfs2_start_trans(osb, OCFS2_GROUP_ADD_CREDITS);
	if (IS_ERR(handle)) {
	mlog_errno(PTR_ERR(handle));
	ret = -EINVAL;
	goto out_free_group_bh;
	}

	cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
	cl = &fe->id2.i_chain;
	cr = &cl->cl_recs[input->chain];

	ret = ocfs2_journal_access_gd(handle, INODE_CACHE(main_bm_inode),
	group_bh, OCFS2_JOURNAL_ACCESS_WRITE);
	if (ret < 0) {
	mlog_errno(ret);
	goto out_commit;
	}

	group = (struct ocfs2_group_desc *)group_bh->b_data;
	bg_ptr = le64_to_cpu(group->bg_next_group);
	group->bg_next_group = cr->c_blkno;
	ocfs2_journal_dirty(handle, group_bh);

	ret = ocfs2_journal_access_di(handle, INODE_CACHE(main_bm_inode),
	main_bm_bh, OCFS2_JOURNAL_ACCESS_WRITE);
	if (ret < 0) {
	group->bg_next_group = cpu_to_le64(bg_ptr);
	mlog_errno(ret);
	goto out_commit;
	}

	if (input->chain == le16_to_cpu(cl->cl_next_free_rec)) {
	le16_add_cpu(&cl->cl_next_free_rec, 1);
	memset(cr, 0, sizeof(struct ocfs2_chain_rec));
	}

	cr->c_blkno = cpu_to_le64(input->group);
	le32_add_cpu(&cr->c_total, input->clusters * cl_bpc);
	le32_add_cpu(&cr->c_free, input->frees * cl_bpc);

	le32_add_cpu(&fe->id1.bitmap1.i_total, input->clusters *cl_bpc);
	le32_add_cpu(&fe->id1.bitmap1.i_used,
	(input->clusters - input->frees) * cl_bpc);
	le32_add_cpu(&fe->i_clusters, input->clusters);

	ocfs2_journal_dirty(handle, main_bm_bh);

	spin_lock(&OCFS2_I(main_bm_inode)->ip_lock);
	OCFS2_I(main_bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
	le64_add_cpu(&fe->i_size, (u64)input->clusters << osb->s_clustersize_bits);
	spin_unlock(&OCFS2_I(main_bm_inode)->ip_lock);
	i_size_write(main_bm_inode, le64_to_cpu(fe->i_size));

	ocfs2_update_super_and_backups(main_bm_inode, input->clusters);

	out_commit:
	ocfs2_commit_trans(osb, handle);

	out_free_group_bh:
	if (ret < 0)
	ocfs2_remove_from_cache(INODE_CACHE(inode), group_bh);
	brelse(group_bh);

	out_unlock:
	brelse(main_bm_bh);

	ocfs2_inode_unlock(main_bm_inode, 1);

	out_mutex:
	inode_unlock(main_bm_inode);
	iput(main_bm_inode);

	out:
	return ret;
	}