fs/quota_v2.c - pub/scm/linux/kernel/git/joro/linux - Git at Google

 /*
  *	vfsv0 quota IO operations on file
  */

 #include <linux/errno.h>
 #include <linux/fs.h>
 #include <linux/mount.h>
 #include <linux/dqblk_v2.h>
 #include <linux/quotaio_v2.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>

 #include <asm/byteorder.h>
 #include <asm/uaccess.h>

 MODULE_AUTHOR("Jan Kara");
 MODULE_DESCRIPTION("Quota format v2 support");
 MODULE_LICENSE("GPL");

 #define __QUOTA_V2_PARANOIA

 typedef char *dqbuf_t;

 #define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
 #define GETENTRIES(buf) ((struct v2_disk_dqblk *)(((char *)buf)+sizeof(struct v2_disk_dqdbheader)))

 /* Check whether given file is really vfsv0 quotafile */
 static int v2_check_quota_file(struct super_block *sb, int type)
 {
 	struct v2_disk_dqheader dqhead;
 	struct file *f = sb_dqopt(sb)->files[type];
 	mm_segment_t fs;
 	ssize_t size;
 	loff_t offset = 0;
 	static const uint quota_magics[] = V2_INITQMAGICS;
 	static const uint quota_versions[] = V2_INITQVERSIONS;

 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	size = f->f_op->read(f, (char *)&dqhead, sizeof(struct v2_disk_dqheader), &offset);
 	set_fs(fs);
 	if (size != sizeof(struct v2_disk_dqheader))
 		return 0;
 	if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
 	    le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
 		return 0;
 	return 1;
 }

 /* Read information header from quota file */
 static int v2_read_file_info(struct super_block *sb, int type)
 {
 	mm_segment_t fs;
 	struct v2_disk_dqinfo dinfo;
 	struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
 	struct file *f = sb_dqopt(sb)->files[type];
 	ssize_t size;
 	loff_t offset = V2_DQINFOOFF;

 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	size = f->f_op->read(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
 	set_fs(fs);
 	if (size != sizeof(struct v2_disk_dqinfo)) {
 		printk(KERN_WARNING "Can't read info structure on device %s.\n",
 			f->f_vfsmnt->mnt_sb->s_id);
 		return -1;
 	}
 	info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
 	info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
 	info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
 	info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
 	info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
 	info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
 	return 0;
 }

 /* Write information header to quota file */
 static int v2_write_file_info(struct super_block *sb, int type)
 {
 	mm_segment_t fs;
 	struct v2_disk_dqinfo dinfo;
 	struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
 	struct file *f = sb_dqopt(sb)->files[type];
 	ssize_t size;
 	loff_t offset = V2_DQINFOOFF;

 	info->dqi_flags &= ~DQF_INFO_DIRTY;
 	dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
 	dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
 	dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
 	dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
 	dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 	dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	size = f->f_op->write(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
 	set_fs(fs);
 	if (size != sizeof(struct v2_disk_dqinfo)) {
 		printk(KERN_WARNING "Can't write info structure on device %s.\n",
 			f->f_vfsmnt->mnt_sb->s_id);
 		return -1;
 	}
 	return 0;
 }

 static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
 {
 	m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
 	m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
 	m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
 	m->dqb_itime = le64_to_cpu(d->dqb_itime);
 	m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
 	m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
 	m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
 	m->dqb_btime = le64_to_cpu(d->dqb_btime);
 }

 static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
 {
 	d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
 	d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
 	d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
 	d->dqb_itime = cpu_to_le64(m->dqb_itime);
 	d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
 	d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
 	d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
 	d->dqb_btime = cpu_to_le64(m->dqb_btime);
 	d->dqb_id = cpu_to_le32(id);
 }

 static dqbuf_t getdqbuf(void)
 {
 	dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_KERNEL);
 	if (!buf)
 		printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
 	return buf;
 }

 static inline void freedqbuf(dqbuf_t buf)
 {
 	kfree(buf);
 }

 static ssize_t read_blk(struct file *filp, uint blk, dqbuf_t buf)
 {
 	mm_segment_t fs;
 	ssize_t ret;
 	loff_t offset = blk<<V2_DQBLKSIZE_BITS;

 	memset(buf, 0, V2_DQBLKSIZE);
 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	ret = filp->f_op->read(filp, (char *)buf, V2_DQBLKSIZE, &offset);
 	set_fs(fs);
 	return ret;
 }

 static ssize_t write_blk(struct file *filp, uint blk, dqbuf_t buf)
 {
 	mm_segment_t fs;
 	ssize_t ret;
 	loff_t offset = blk<<V2_DQBLKSIZE_BITS;

 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	ret = filp->f_op->write(filp, (char *)buf, V2_DQBLKSIZE, &offset);
 	set_fs(fs);
 	return ret;

 }

 /* Remove empty block from list and return it */
 static int get_free_dqblk(struct file *filp, struct mem_dqinfo *info)
 {
 	dqbuf_t buf = getdqbuf();
 	struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 	int ret, blk;

 	if (!buf)
 		return -ENOMEM;
 	if (info->u.v2_i.dqi_free_blk) {
 		blk = info->u.v2_i.dqi_free_blk;
 		if ((ret = read_blk(filp, blk, buf)) < 0)
 			goto out_buf;
 		info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
 	}
 	else {
 		memset(buf, 0, V2_DQBLKSIZE);
 		if ((ret = write_blk(filp, info->u.v2_i.dqi_blocks, buf)) < 0)	/* Assure block allocation... */
 			goto out_buf;
 		blk = info->u.v2_i.dqi_blocks++;
 	}
 	mark_info_dirty(info);
 	ret = blk;
 out_buf:
 	freedqbuf(buf);
 	return ret;
 }

 /* Insert empty block to the list */
 static int put_free_dqblk(struct file *filp, struct mem_dqinfo *info, dqbuf_t buf, uint blk)
 {
 	struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 	int err;

 	dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 	dh->dqdh_prev_free = cpu_to_le32(0);
 	dh->dqdh_entries = cpu_to_le16(0);
 	info->u.v2_i.dqi_free_blk = blk;
 	mark_info_dirty(info);
 	if ((err = write_blk(filp, blk, buf)) < 0)	/* Some strange block. We had better leave it... */
 		return err;
 	return 0;
 }

 /* Remove given block from the list of blocks with free entries */
 static int remove_free_dqentry(struct file *filp, struct mem_dqinfo *info, dqbuf_t buf, uint blk)
 {
 	dqbuf_t tmpbuf = getdqbuf();
 	struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 	uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
 	int err;

 	if (!tmpbuf)
 		return -ENOMEM;
 	if (nextblk) {
 		if ((err = read_blk(filp, nextblk, tmpbuf)) < 0)
 			goto out_buf;
 		((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
 		if ((err = write_blk(filp, nextblk, tmpbuf)) < 0)
 			goto out_buf;
 	}
 	if (prevblk) {
 		if ((err = read_blk(filp, prevblk, tmpbuf)) < 0)
 			goto out_buf;
 		((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
 		if ((err = write_blk(filp, prevblk, tmpbuf)) < 0)
 			goto out_buf;
 	}
 	else {
 		info->u.v2_i.dqi_free_entry = nextblk;
 		mark_info_dirty(info);
 	}
 	freedqbuf(tmpbuf);
 	dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 	if (write_blk(filp, blk, buf) < 0)	/* No matter whether write succeeds block is out of list */
 		printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
 	return 0;
 out_buf:
 	freedqbuf(tmpbuf);
 	return err;
 }

 /* Insert given block to the beginning of list with free entries */
 static int insert_free_dqentry(struct file *filp, struct mem_dqinfo *info, dqbuf_t buf, uint blk)
 {
 	dqbuf_t tmpbuf = getdqbuf();
 	struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 	int err;

 	if (!tmpbuf)
 		return -ENOMEM;
 	dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 	dh->dqdh_prev_free = cpu_to_le32(0);
 	if ((err = write_blk(filp, blk, buf)) < 0)
 		goto out_buf;
 	if (info->u.v2_i.dqi_free_entry) {
 		if ((err = read_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 			goto out_buf;
 		((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
 		if ((err = write_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 			goto out_buf;
 	}
 	freedqbuf(tmpbuf);
 	info->u.v2_i.dqi_free_entry = blk;
 	mark_info_dirty(info);
 	return 0;
 out_buf:
 	freedqbuf(tmpbuf);
 	return err;
 }

 /* Find space for dquot */
 static uint find_free_dqentry(struct dquot *dquot, int *err)
 {
 	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info+dquot->dq_type;
 	uint blk, i;
 	struct v2_disk_dqdbheader *dh;
 	struct v2_disk_dqblk *ddquot;
 	struct v2_disk_dqblk fakedquot;
 	dqbuf_t buf;

 	*err = 0;
 	if (!(buf = getdqbuf())) {
 		*err = -ENOMEM;
 		return 0;
 	}
 	dh = (struct v2_disk_dqdbheader *)buf;
 	ddquot = GETENTRIES(buf);
 	if (info->u.v2_i.dqi_free_entry) {
 		blk = info->u.v2_i.dqi_free_entry;
 		if ((*err = read_blk(filp, blk, buf)) < 0)
 			goto out_buf;
 	}
 	else {
 		blk = get_free_dqblk(filp, info);
 		if ((int)blk < 0) {
 			*err = blk;
 			freedqbuf(buf);
 			return 0;
 		}
 		memset(buf, 0, V2_DQBLKSIZE);
 		info->u.v2_i.dqi_free_entry = blk;	/* This is enough as block is already zeroed and entry list is empty... */
 		mark_info_dirty(info);
 	}
 	if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)	/* Block will be full? */
 		if ((*err = remove_free_dqentry(filp, info, buf, blk)) < 0) {
 			printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
 			goto out_buf;
 		}
 	dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)+1);
 	memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 	/* Find free structure in block */
 	for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
 #ifdef __QUOTA_V2_PARANOIA
 	if (i == V2_DQSTRINBLK) {
 		printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
 		*err = -EIO;
 		goto out_buf;
 	}
 #endif
 	if ((*err = write_blk(filp, blk, buf)) < 0) {
 		printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
 		goto out_buf;
 	}
 	dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
 	freedqbuf(buf);
 	return blk;
 out_buf:
 	freedqbuf(buf);
 	return 0;
 }

 /* Insert reference to structure into the trie */
 static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
 {
 	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
 	dqbuf_t buf;
 	int ret = 0, newson = 0, newact = 0;
 	u32 *ref;
 	uint newblk;

 	if (!(buf = getdqbuf()))
 		return -ENOMEM;
 	if (!*treeblk) {
 		ret = get_free_dqblk(filp, info);
 		if (ret < 0)
 			goto out_buf;
 		*treeblk = ret;
 		memset(buf, 0, V2_DQBLKSIZE);
 		newact = 1;
 	}
 	else {
 		if ((ret = read_blk(filp, *treeblk, buf)) < 0) {
 			printk(KERN_ERR "VFS: Can't read tree quota block %u.\n", *treeblk);
 			goto out_buf;
 		}
 	}
 	ref = (u32 *)buf;
 	newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 	if (!newblk)
 		newson = 1;
 	if (depth == V2_DQTREEDEPTH-1) {
 #ifdef __QUOTA_V2_PARANOIA
 		if (newblk) {
 			printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", ref[GETIDINDEX(dquot->dq_id, depth)]);
 			ret = -EIO;
 			goto out_buf;
 		}
 #endif
 		newblk = find_free_dqentry(dquot, &ret);
 	}
 	else
 		ret = do_insert_tree(dquot, &newblk, depth+1);
 	if (newson && ret >= 0) {
 		ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
 		ret = write_blk(filp, *treeblk, buf);
 	}
 	else if (newact && ret < 0)
 		put_free_dqblk(filp, info, buf, *treeblk);
 out_buf:
 	freedqbuf(buf);
 	return ret;
 }

 /* Wrapper for inserting quota structure into tree */
 static inline int dq_insert_tree(struct dquot *dquot)
 {
 	int tmp = V2_DQTREEOFF;
 	return do_insert_tree(dquot, &tmp, 0);
 }

 /*
  *	We don't have to be afraid of deadlocks as we never have quotas on quota files...
  */
 static int v2_write_dquot(struct dquot *dquot)
 {
 	int type = dquot->dq_type;
 	struct file *filp;
 	mm_segment_t fs;
 	loff_t offset;
 	ssize_t ret;
 	struct v2_disk_dqblk ddquot;

 	if (!dquot->dq_off)
 		if ((ret = dq_insert_tree(dquot)) < 0) {
 			printk(KERN_ERR "VFS: Error %Zd occurred while creating quota.\n", ret);
 			return ret;
 		}
 	filp = sb_dqopt(dquot->dq_sb)->files[type];
 	offset = dquot->dq_off;
 	mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	ret = filp->f_op->write(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset);
 	set_fs(fs);
 	if (ret != sizeof(struct v2_disk_dqblk)) {
 		printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
 		if (ret >= 0)
 			ret = -ENOSPC;
 	}
 	else
 		ret = 0;
 	dqstats.writes++;

 	return ret;
 }

 /* Free dquot entry in data block */
 static int free_dqentry(struct dquot *dquot, uint blk)
 {
 	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
 	struct v2_disk_dqdbheader *dh;
 	dqbuf_t buf = getdqbuf();
 	int ret = 0;

 	if (!buf)
 		return -ENOMEM;
 	if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
 		printk(KERN_ERR "VFS: Quota structure has offset to other block (%u) than it should (%u).\n", blk, (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
 		goto out_buf;
 	}
 	if ((ret = read_blk(filp, blk, buf)) < 0) {
 		printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
 		goto out_buf;
 	}
 	dh = (struct v2_disk_dqdbheader *)buf;
 	dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)-1);
 	if (!le16_to_cpu(dh->dqdh_entries)) {	/* Block got free? */
 		if ((ret = remove_free_dqentry(filp, info, buf, blk)) < 0 ||
 		    (ret = put_free_dqblk(filp, info, buf, blk)) < 0) {
 			printk(KERN_ERR "VFS: Can't move quota data block (%u) to free list.\n", blk);
 			goto out_buf;
 		}
 	}
 	else {
 		memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0, sizeof(struct v2_disk_dqblk));
 		if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
 			/* Insert will write block itself */
 			if ((ret = insert_free_dqentry(filp, info, buf, blk)) < 0) {
 				printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
 				goto out_buf;
 			}
 		}
 		else
 			if ((ret = write_blk(filp, blk, buf)) < 0) {
 				printk(KERN_ERR "VFS: Can't write quota data block %u\n", blk);
 				goto out_buf;
 			}
 	}
 	dquot->dq_off = 0;	/* Quota is now unattached */
 out_buf:
 	freedqbuf(buf);
 	return ret;
 }

 /* Remove reference to dquot from tree */
 static int remove_tree(struct dquot *dquot, uint *blk, int depth)
 {
 	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
 	dqbuf_t buf = getdqbuf();
 	int ret = 0;
 	uint newblk;
 	u32 *ref = (u32 *)buf;

 	if (!buf)
 		return -ENOMEM;
 	if ((ret = read_blk(filp, *blk, buf)) < 0) {
 		printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
 		goto out_buf;
 	}
 	newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 	if (depth == V2_DQTREEDEPTH-1) {
 		ret = free_dqentry(dquot, newblk);
 		newblk = 0;
 	}
 	else
 		ret = remove_tree(dquot, &newblk, depth+1);
 	if (ret >= 0 && !newblk) {
 		int i;
 		ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
 		for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);	/* Block got empty? */
 		if (i == V2_DQBLKSIZE) {
 			put_free_dqblk(filp, info, buf, *blk);
 			*blk = 0;
 		}
 		else
 			if ((ret = write_blk(filp, *blk, buf)) < 0)
 				printk(KERN_ERR "VFS: Can't write quota tree block %u.\n", *blk);
 	}
 out_buf:
 	freedqbuf(buf);
 	return ret;
 }

 /* Delete dquot from tree */
 static int v2_delete_dquot(struct dquot *dquot)
 {
 	uint tmp = V2_DQTREEOFF;

 	if (!dquot->dq_off)	/* Even not allocated? */
 		return 0;
 	return remove_tree(dquot, &tmp, 0);
 }

 /* Find entry in block */
 static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
 {
 	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 	dqbuf_t buf = getdqbuf();
 	loff_t ret = 0;
 	int i;
 	struct v2_disk_dqblk *ddquot = GETENTRIES(buf);

 	if (!buf)
 		return -ENOMEM;
 	if ((ret = read_blk(filp, blk, buf)) < 0) {
 		printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 		goto out_buf;
 	}
 	if (dquot->dq_id)
 		for (i = 0; i < V2_DQSTRINBLK && le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
 	else {	/* ID 0 as a bit more complicated searching... */
 		struct v2_disk_dqblk fakedquot;

 		memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 		for (i = 0; i < V2_DQSTRINBLK; i++)
 			if (!le32_to_cpu(ddquot[i].dqb_id) && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
 				break;
 	}
 	if (i == V2_DQSTRINBLK) {
 		printk(KERN_ERR "VFS: Quota for id %u referenced but not present.\n", dquot->dq_id);
 		ret = -EIO;
 		goto out_buf;
 	}
 	else
 		ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
 out_buf:
 	freedqbuf(buf);
 	return ret;
 }

 /* Find entry for given id in the tree */
 static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
 {
 	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 	dqbuf_t buf = getdqbuf();
 	loff_t ret = 0;
 	u32 *ref = (u32 *)buf;

 	if (!buf)
 		return -ENOMEM;
 	if ((ret = read_blk(filp, blk, buf)) < 0) {
 		printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 		goto out_buf;
 	}
 	ret = 0;
 	blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 	if (!blk)	/* No reference? */
 		goto out_buf;
 	if (depth < V2_DQTREEDEPTH-1)
 		ret = find_tree_dqentry(dquot, blk, depth+1);
 	else
 		ret = find_block_dqentry(dquot, blk);
 out_buf:
 	freedqbuf(buf);
 	return ret;
 }

 /* Find entry for given id in the tree - wrapper function */
 static inline loff_t find_dqentry(struct dquot *dquot)
 {
 	return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
 }

 static int v2_read_dquot(struct dquot *dquot)
 {
 	int type = dquot->dq_type;
 	struct file *filp;
 	mm_segment_t fs;
 	loff_t offset;
 	struct v2_disk_dqblk ddquot;
 	int ret = 0;

 	filp = sb_dqopt(dquot->dq_sb)->files[type];

 #ifdef __QUOTA_V2_PARANOIA
 	if (!filp || !dquot->dq_sb) {	/* Invalidated quota? */
 		printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
 		return -EIO;
 	}
 #endif
 	offset = find_dqentry(dquot);
 	if (offset <= 0) {	/* Entry not present? */
 		if (offset < 0)
 			printk(KERN_ERR "VFS: Can't read quota structure for id %u.\n", dquot->dq_id);
 		dquot->dq_off = 0;
 		dquot->dq_flags |= DQ_FAKE;
 		memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 		ret = offset;
 	}
 	else {
 		dquot->dq_off = offset;
 		fs = get_fs();
 		set_fs(KERNEL_DS);
 		if ((ret = filp->f_op->read(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset)) != sizeof(struct v2_disk_dqblk)) {
 			if (ret >= 0)
 				ret = -EIO;
 			printk(KERN_ERR "VFS: Error while reading quota structure for id %u.\n", dquot->dq_id);
 			memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
 		}
 		else
 			ret = 0;
 		set_fs(fs);
 		disk2memdqb(&dquot->dq_dqb, &ddquot);
 	}
 	dqstats.reads++;

 	return ret;
 }

 /* Commit changes of dquot to disk - it might also mean deleting it when quota became fake one and user has no blocks... */
 static int v2_commit_dquot(struct dquot *dquot)
 {
 	/* We clear the flag everytime so we don't loop when there was an IO error... */
 	dquot->dq_flags &= ~DQ_MOD;
 	if (dquot->dq_flags & DQ_FAKE && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 		return v2_delete_dquot(dquot);
 	else
 		return v2_write_dquot(dquot);
 }

 static struct quota_format_ops v2_format_ops = {
 	.check_quota_file	= v2_check_quota_file,
 	.read_file_info		= v2_read_file_info,
 	.write_file_info	= v2_write_file_info,
 	.free_file_info		= NULL,
 	.read_dqblk		= v2_read_dquot,
 	.commit_dqblk		= v2_commit_dquot,
 };

 static struct quota_format_type v2_quota_format = {
 	.qf_fmt_id	= QFMT_VFS_V0,
 	.qf_ops		= &v2_format_ops,
 	.qf_owner	= THIS_MODULE
 };

 static int __init init_v2_quota_format(void)
 {
 	return register_quota_format(&v2_quota_format);
 }

 static void __exit exit_v2_quota_format(void)
 {
 	unregister_quota_format(&v2_quota_format);
 }

 module_init(init_v2_quota_format);
 module_exit(exit_v2_quota_format);
	/*
	* vfsv0 quota IO operations on file
	*/

	#include <linux/errno.h>
	#include <linux/fs.h>
	#include <linux/mount.h>
	#include <linux/dqblk_v2.h>
	#include <linux/quotaio_v2.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/slab.h>

	#include <asm/byteorder.h>
	#include <asm/uaccess.h>

	MODULE_AUTHOR("Jan Kara");
	MODULE_DESCRIPTION("Quota format v2 support");
	MODULE_LICENSE("GPL");

	#define __QUOTA_V2_PARANOIA

	typedef char *dqbuf_t;

	#define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
	#define GETENTRIES(buf) ((struct v2_disk_dqblk )(((char )buf)+sizeof(struct v2_disk_dqdbheader)))

	/* Check whether given file is really vfsv0 quotafile */
	static int v2_check_quota_file(struct super_block *sb, int type)
	{
	struct v2_disk_dqheader dqhead;
	struct file *f = sb_dqopt(sb)->files[type];
	mm_segment_t fs;
	ssize_t size;
	loff_t offset = 0;
	static const uint quota_magics[] = V2_INITQMAGICS;
	static const uint quota_versions[] = V2_INITQVERSIONS;

	fs = get_fs();
	set_fs(KERNEL_DS);
	size = f->f_op->read(f, (char *)&dqhead, sizeof(struct v2_disk_dqheader), &offset);
	set_fs(fs);
	if (size != sizeof(struct v2_disk_dqheader))
	return 0;
	if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] \|\|
	le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
	return 0;
	return 1;
	}

	/* Read information header from quota file */
	static int v2_read_file_info(struct super_block *sb, int type)
	{
	mm_segment_t fs;
	struct v2_disk_dqinfo dinfo;
	struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
	struct file *f = sb_dqopt(sb)->files[type];
	ssize_t size;
	loff_t offset = V2_DQINFOOFF;

	fs = get_fs();
	set_fs(KERNEL_DS);
	size = f->f_op->read(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
	set_fs(fs);
	if (size != sizeof(struct v2_disk_dqinfo)) {
	printk(KERN_WARNING "Can't read info structure on device %s.\n",
	f->f_vfsmnt->mnt_sb->s_id);
	return -1;
	}
	info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
	info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
	info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
	info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
	info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
	info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
	return 0;
	}

	/* Write information header to quota file */
	static int v2_write_file_info(struct super_block *sb, int type)
	{
	mm_segment_t fs;
	struct v2_disk_dqinfo dinfo;
	struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
	struct file *f = sb_dqopt(sb)->files[type];
	ssize_t size;
	loff_t offset = V2_DQINFOOFF;

	info->dqi_flags &= ~DQF_INFO_DIRTY;
	dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
	dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
	dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
	dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
	dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
	dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
	fs = get_fs();
	set_fs(KERNEL_DS);
	size = f->f_op->write(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
	set_fs(fs);
	if (size != sizeof(struct v2_disk_dqinfo)) {
	printk(KERN_WARNING "Can't write info structure on device %s.\n",
	f->f_vfsmnt->mnt_sb->s_id);
	return -1;
	}
	return 0;
	}

	static void disk2memdqb(struct mem_dqblk m, struct v2_disk_dqblk d)
	{
	m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
	m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
	m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
	m->dqb_itime = le64_to_cpu(d->dqb_itime);
	m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
	m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
	m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
	m->dqb_btime = le64_to_cpu(d->dqb_btime);
	}

	static void mem2diskdqb(struct v2_disk_dqblk d, struct mem_dqblk m, qid_t id)
	{
	d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
	d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
	d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
	d->dqb_itime = cpu_to_le64(m->dqb_itime);
	d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
	d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
	d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
	d->dqb_btime = cpu_to_le64(m->dqb_btime);
	d->dqb_id = cpu_to_le32(id);
	}

	static dqbuf_t getdqbuf(void)
	{
	dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_KERNEL);
	if (!buf)
	printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
	return buf;
	}

	static inline void freedqbuf(dqbuf_t buf)
	{
	kfree(buf);
	}

	static ssize_t read_blk(struct file *filp, uint blk, dqbuf_t buf)
	{
	mm_segment_t fs;
	ssize_t ret;
	loff_t offset = blk<<V2_DQBLKSIZE_BITS;

	memset(buf, 0, V2_DQBLKSIZE);
	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = filp->f_op->read(filp, (char *)buf, V2_DQBLKSIZE, &offset);
	set_fs(fs);
	return ret;
	}

	static ssize_t write_blk(struct file *filp, uint blk, dqbuf_t buf)
	{
	mm_segment_t fs;
	ssize_t ret;
	loff_t offset = blk<<V2_DQBLKSIZE_BITS;

	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = filp->f_op->write(filp, (char *)buf, V2_DQBLKSIZE, &offset);
	set_fs(fs);
	return ret;

	}

	/* Remove empty block from list and return it */
	static int get_free_dqblk(struct file filp, struct mem_dqinfo info)
	{
	dqbuf_t buf = getdqbuf();
	struct v2_disk_dqdbheader dh = (struct v2_disk_dqdbheader )buf;
	int ret, blk;

	if (!buf)
	return -ENOMEM;
	if (info->u.v2_i.dqi_free_blk) {
	blk = info->u.v2_i.dqi_free_blk;
	if ((ret = read_blk(filp, blk, buf)) < 0)
	goto out_buf;
	info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
	}
	else {
	memset(buf, 0, V2_DQBLKSIZE);
	if ((ret = write_blk(filp, info->u.v2_i.dqi_blocks, buf)) < 0) /* Assure block allocation... */
	goto out_buf;
	blk = info->u.v2_i.dqi_blocks++;
	}
	mark_info_dirty(info);
	ret = blk;
	out_buf:
	freedqbuf(buf);
	return ret;
	}

	/* Insert empty block to the list */
	static int put_free_dqblk(struct file filp, struct mem_dqinfo info, dqbuf_t buf, uint blk)
	{
	struct v2_disk_dqdbheader dh = (struct v2_disk_dqdbheader )buf;
	int err;

	dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
	dh->dqdh_prev_free = cpu_to_le32(0);
	dh->dqdh_entries = cpu_to_le16(0);
	info->u.v2_i.dqi_free_blk = blk;
	mark_info_dirty(info);
	if ((err = write_blk(filp, blk, buf)) < 0) /* Some strange block. We had better leave it... */
	return err;
	return 0;
	}

	/* Remove given block from the list of blocks with free entries */
	static int remove_free_dqentry(struct file filp, struct mem_dqinfo info, dqbuf_t buf, uint blk)
	{
	dqbuf_t tmpbuf = getdqbuf();
	struct v2_disk_dqdbheader dh = (struct v2_disk_dqdbheader )buf;
	uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
	int err;

	if (!tmpbuf)
	return -ENOMEM;
	if (nextblk) {
	if ((err = read_blk(filp, nextblk, tmpbuf)) < 0)
	goto out_buf;
	((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
	if ((err = write_blk(filp, nextblk, tmpbuf)) < 0)
	goto out_buf;
	}
	if (prevblk) {
	if ((err = read_blk(filp, prevblk, tmpbuf)) < 0)
	goto out_buf;
	((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
	if ((err = write_blk(filp, prevblk, tmpbuf)) < 0)
	goto out_buf;
	}
	else {
	info->u.v2_i.dqi_free_entry = nextblk;
	mark_info_dirty(info);
	}
	freedqbuf(tmpbuf);
	dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
	if (write_blk(filp, blk, buf) < 0) /* No matter whether write succeeds block is out of list */
	printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
	return 0;
	out_buf:
	freedqbuf(tmpbuf);
	return err;
	}

	/* Insert given block to the beginning of list with free entries */
	static int insert_free_dqentry(struct file filp, struct mem_dqinfo info, dqbuf_t buf, uint blk)
	{
	dqbuf_t tmpbuf = getdqbuf();
	struct v2_disk_dqdbheader dh = (struct v2_disk_dqdbheader )buf;
	int err;

	if (!tmpbuf)
	return -ENOMEM;
	dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
	dh->dqdh_prev_free = cpu_to_le32(0);
	if ((err = write_blk(filp, blk, buf)) < 0)
	goto out_buf;
	if (info->u.v2_i.dqi_free_entry) {
	if ((err = read_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
	goto out_buf;
	((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
	if ((err = write_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
	goto out_buf;
	}
	freedqbuf(tmpbuf);
	info->u.v2_i.dqi_free_entry = blk;
	mark_info_dirty(info);
	return 0;
	out_buf:
	freedqbuf(tmpbuf);
	return err;
	}

	/* Find space for dquot */
	static uint find_free_dqentry(struct dquot dquot, int err)
	{
	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info+dquot->dq_type;
	uint blk, i;
	struct v2_disk_dqdbheader *dh;
	struct v2_disk_dqblk *ddquot;
	struct v2_disk_dqblk fakedquot;
	dqbuf_t buf;

	*err = 0;
	if (!(buf = getdqbuf())) {
	*err = -ENOMEM;
	return 0;
	}
	dh = (struct v2_disk_dqdbheader *)buf;
	ddquot = GETENTRIES(buf);
	if (info->u.v2_i.dqi_free_entry) {
	blk = info->u.v2_i.dqi_free_entry;
	if ((*err = read_blk(filp, blk, buf)) < 0)
	goto out_buf;
	}
	else {
	blk = get_free_dqblk(filp, info);
	if ((int)blk < 0) {
	*err = blk;
	freedqbuf(buf);
	return 0;
	}
	memset(buf, 0, V2_DQBLKSIZE);
	info->u.v2_i.dqi_free_entry = blk; /* This is enough as block is already zeroed and entry list is empty... */
	mark_info_dirty(info);
	}
	if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK) /* Block will be full? */
	if ((*err = remove_free_dqentry(filp, info, buf, blk)) < 0) {
	printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
	goto out_buf;
	}
	dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)+1);
	memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
	/* Find free structure in block */
	for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
	#ifdef __QUOTA_V2_PARANOIA
	if (i == V2_DQSTRINBLK) {
	printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
	*err = -EIO;
	goto out_buf;
	}
	#endif
	if ((*err = write_blk(filp, blk, buf)) < 0) {
	printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
	goto out_buf;
	}
	dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
	freedqbuf(buf);
	return blk;
	out_buf:
	freedqbuf(buf);
	return 0;
	}

	/* Insert reference to structure into the trie */
	static int do_insert_tree(struct dquot dquot, uint treeblk, int depth)
	{
	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
	dqbuf_t buf;
	int ret = 0, newson = 0, newact = 0;
	u32 *ref;
	uint newblk;

	if (!(buf = getdqbuf()))
	return -ENOMEM;
	if (!*treeblk) {
	ret = get_free_dqblk(filp, info);
	if (ret < 0)
	goto out_buf;
	*treeblk = ret;
	memset(buf, 0, V2_DQBLKSIZE);
	newact = 1;
	}
	else {
	if ((ret = read_blk(filp, *treeblk, buf)) < 0) {
	printk(KERN_ERR "VFS: Can't read tree quota block %u.\n", *treeblk);
	goto out_buf;
	}
	}
	ref = (u32 *)buf;
	newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
	if (!newblk)
	newson = 1;
	if (depth == V2_DQTREEDEPTH-1) {
	#ifdef __QUOTA_V2_PARANOIA
	if (newblk) {
	printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", ref[GETIDINDEX(dquot->dq_id, depth)]);
	ret = -EIO;
	goto out_buf;
	}
	#endif
	newblk = find_free_dqentry(dquot, &ret);
	}
	else
	ret = do_insert_tree(dquot, &newblk, depth+1);
	if (newson && ret >= 0) {
	ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
	ret = write_blk(filp, *treeblk, buf);
	}
	else if (newact && ret < 0)
	put_free_dqblk(filp, info, buf, *treeblk);
	out_buf:
	freedqbuf(buf);
	return ret;
	}

	/* Wrapper for inserting quota structure into tree */
	static inline int dq_insert_tree(struct dquot *dquot)
	{
	int tmp = V2_DQTREEOFF;
	return do_insert_tree(dquot, &tmp, 0);
	}

	/*
	* We don't have to be afraid of deadlocks as we never have quotas on quota files...
	*/
	static int v2_write_dquot(struct dquot *dquot)
	{
	int type = dquot->dq_type;
	struct file *filp;
	mm_segment_t fs;
	loff_t offset;
	ssize_t ret;
	struct v2_disk_dqblk ddquot;

	if (!dquot->dq_off)
	if ((ret = dq_insert_tree(dquot)) < 0) {
	printk(KERN_ERR "VFS: Error %Zd occurred while creating quota.\n", ret);
	return ret;
	}
	filp = sb_dqopt(dquot->dq_sb)->files[type];
	offset = dquot->dq_off;
	mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = filp->f_op->write(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset);
	set_fs(fs);
	if (ret != sizeof(struct v2_disk_dqblk)) {
	printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
	if (ret >= 0)
	ret = -ENOSPC;
	}
	else
	ret = 0;
	dqstats.writes++;

	return ret;
	}

	/* Free dquot entry in data block */
	static int free_dqentry(struct dquot *dquot, uint blk)
	{
	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
	struct v2_disk_dqdbheader *dh;
	dqbuf_t buf = getdqbuf();
	int ret = 0;

	if (!buf)
	return -ENOMEM;
	if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
	printk(KERN_ERR "VFS: Quota structure has offset to other block (%u) than it should (%u).\n", blk, (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
	goto out_buf;
	}
	if ((ret = read_blk(filp, blk, buf)) < 0) {
	printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
	goto out_buf;
	}
	dh = (struct v2_disk_dqdbheader *)buf;
	dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)-1);
	if (!le16_to_cpu(dh->dqdh_entries)) { /* Block got free? */
	if ((ret = remove_free_dqentry(filp, info, buf, blk)) < 0 \|\|
	(ret = put_free_dqblk(filp, info, buf, blk)) < 0) {
	printk(KERN_ERR "VFS: Can't move quota data block (%u) to free list.\n", blk);
	goto out_buf;
	}
	}
	else {
	memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0, sizeof(struct v2_disk_dqblk));
	if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
	/* Insert will write block itself */
	if ((ret = insert_free_dqentry(filp, info, buf, blk)) < 0) {
	printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
	goto out_buf;
	}
	}
	else
	if ((ret = write_blk(filp, blk, buf)) < 0) {
	printk(KERN_ERR "VFS: Can't write quota data block %u\n", blk);
	goto out_buf;
	}
	}
	dquot->dq_off = 0; /* Quota is now unattached */
	out_buf:
	freedqbuf(buf);
	return ret;
	}

	/* Remove reference to dquot from tree */
	static int remove_tree(struct dquot dquot, uint blk, int depth)
	{
	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
	struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
	dqbuf_t buf = getdqbuf();
	int ret = 0;
	uint newblk;
	u32 ref = (u32 )buf;

	if (!buf)
	return -ENOMEM;
	if ((ret = read_blk(filp, *blk, buf)) < 0) {
	printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
	goto out_buf;
	}
	newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
	if (depth == V2_DQTREEDEPTH-1) {
	ret = free_dqentry(dquot, newblk);
	newblk = 0;
	}
	else
	ret = remove_tree(dquot, &newblk, depth+1);
	if (ret >= 0 && !newblk) {
	int i;
	ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
	for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++); /* Block got empty? */
	if (i == V2_DQBLKSIZE) {
	put_free_dqblk(filp, info, buf, *blk);
	*blk = 0;
	}
	else
	if ((ret = write_blk(filp, *blk, buf)) < 0)
	printk(KERN_ERR "VFS: Can't write quota tree block %u.\n", *blk);
	}
	out_buf:
	freedqbuf(buf);
	return ret;
	}

	/* Delete dquot from tree */
	static int v2_delete_dquot(struct dquot *dquot)
	{
	uint tmp = V2_DQTREEOFF;

	if (!dquot->dq_off) /* Even not allocated? */
	return 0;
	return remove_tree(dquot, &tmp, 0);
	}

	/* Find entry in block */
	static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
	{
	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
	dqbuf_t buf = getdqbuf();
	loff_t ret = 0;
	int i;
	struct v2_disk_dqblk *ddquot = GETENTRIES(buf);

	if (!buf)
	return -ENOMEM;
	if ((ret = read_blk(filp, blk, buf)) < 0) {
	printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
	goto out_buf;
	}
	if (dquot->dq_id)
	for (i = 0; i < V2_DQSTRINBLK && le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
	else { /* ID 0 as a bit more complicated searching... */
	struct v2_disk_dqblk fakedquot;

	memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
	for (i = 0; i < V2_DQSTRINBLK; i++)
	if (!le32_to_cpu(ddquot[i].dqb_id) && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
	break;
	}
	if (i == V2_DQSTRINBLK) {
	printk(KERN_ERR "VFS: Quota for id %u referenced but not present.\n", dquot->dq_id);
	ret = -EIO;
	goto out_buf;
	}
	else
	ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
	out_buf:
	freedqbuf(buf);
	return ret;
	}

	/* Find entry for given id in the tree */
	static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
	{
	struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
	dqbuf_t buf = getdqbuf();
	loff_t ret = 0;
	u32 ref = (u32 )buf;

	if (!buf)
	return -ENOMEM;
	if ((ret = read_blk(filp, blk, buf)) < 0) {
	printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
	goto out_buf;
	}
	ret = 0;
	blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
	if (!blk) /* No reference? */
	goto out_buf;
	if (depth < V2_DQTREEDEPTH-1)
	ret = find_tree_dqentry(dquot, blk, depth+1);
	else
	ret = find_block_dqentry(dquot, blk);
	out_buf:
	freedqbuf(buf);
	return ret;
	}

	/* Find entry for given id in the tree - wrapper function */
	static inline loff_t find_dqentry(struct dquot *dquot)
	{
	return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
	}

	static int v2_read_dquot(struct dquot *dquot)
	{
	int type = dquot->dq_type;
	struct file *filp;
	mm_segment_t fs;
	loff_t offset;
	struct v2_disk_dqblk ddquot;
	int ret = 0;

	filp = sb_dqopt(dquot->dq_sb)->files[type];

	#ifdef __QUOTA_V2_PARANOIA
	if (!filp \|\| !dquot->dq_sb) { /* Invalidated quota? */
	printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
	return -EIO;
	}
	#endif
	offset = find_dqentry(dquot);
	if (offset <= 0) { /* Entry not present? */
	if (offset < 0)
	printk(KERN_ERR "VFS: Can't read quota structure for id %u.\n", dquot->dq_id);
	dquot->dq_off = 0;
	dquot->dq_flags \|= DQ_FAKE;
	memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
	ret = offset;
	}
	else {
	dquot->dq_off = offset;
	fs = get_fs();
	set_fs(KERNEL_DS);
	if ((ret = filp->f_op->read(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset)) != sizeof(struct v2_disk_dqblk)) {
	if (ret >= 0)
	ret = -EIO;
	printk(KERN_ERR "VFS: Error while reading quota structure for id %u.\n", dquot->dq_id);
	memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
	}
	else
	ret = 0;
	set_fs(fs);
	disk2memdqb(&dquot->dq_dqb, &ddquot);
	}
	dqstats.reads++;

	return ret;
	}

	/* Commit changes of dquot to disk - it might also mean deleting it when quota became fake one and user has no blocks... */
	static int v2_commit_dquot(struct dquot *dquot)
	{
	/* We clear the flag everytime so we don't loop when there was an IO error... */
	dquot->dq_flags &= ~DQ_MOD;
	if (dquot->dq_flags & DQ_FAKE && !(dquot->dq_dqb.dqb_curinodes \| dquot->dq_dqb.dqb_curspace))
	return v2_delete_dquot(dquot);
	else
	return v2_write_dquot(dquot);
	}

	static struct quota_format_ops v2_format_ops = {
	.check_quota_file = v2_check_quota_file,
	.read_file_info = v2_read_file_info,
	.write_file_info = v2_write_file_info,
	.free_file_info = NULL,
	.read_dqblk = v2_read_dquot,
	.commit_dqblk = v2_commit_dquot,
	};

	static struct quota_format_type v2_quota_format = {
	.qf_fmt_id = QFMT_VFS_V0,
	.qf_ops = &v2_format_ops,
	.qf_owner = THIS_MODULE
	};

	static int __init init_v2_quota_format(void)
	{
	return register_quota_format(&v2_quota_format);
	}

	static void __exit exit_v2_quota_format(void)
	{
	unregister_quota_format(&v2_quota_format);
	}

	module_init(init_v2_quota_format);
	module_exit(exit_v2_quota_format);