dquot.c

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				schedule();	/* Try to wait for a moment... */
			goto we_slept;
		}
		dquot = empty;
        	dquot->dq_id = id;
        	dquot->dq_type = type;
        	dquot->dq_dev = sb->s_dev;
        	dquot->dq_sb = sb;
		/* hash it first so it can be found */
		insert_dquot_hash(dquot);
        	read_dquot(dquot);
	} else {
		if (!dquot->dq_count++)
			remove_free_dquot(dquot);
		dqstats.cache_hits++;
		wait_on_dquot(dquot);
		if (empty)
			dqput(empty);
	}

	if (!dquot->dq_sb) {	/* Has somebody invalidated entry under us? */
		printk(KERN_ERR "VFS: dqget(): Quota invalidated in dqget()!\n");
		dqput(dquot);
		return NODQUOT;
	}
	dquot->dq_referenced++;
	dqstats.lookups++;

	return dquot;
}

static struct dquot *dqduplicate(struct dquot *dquot)
{
	if (dquot == NODQUOT)
		return NODQUOT;
	dquot->dq_count++;
	if (!dquot->dq_sb) {
		printk(KERN_ERR "VFS: dqduplicate(): Invalidated quota to be duplicated!\n");
		dquot->dq_count--;
		return NODQUOT;
	}
	if (dquot->dq_flags & DQ_LOCKED)
		printk(KERN_ERR "VFS: dqduplicate(): Locked quota to be duplicated!\n");
	dquot->dq_referenced++;
	dqstats.lookups++;
	return dquot;
}

static int dqinit_needed(struct inode *inode, short type)
{
	int cnt;

	if (IS_NOQUOTA(inode))
		return 0;
	if (type != -1)
		return inode->i_dquot[type] == NODQUOT;
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		if (inode->i_dquot[cnt] == NODQUOT)
			return 1;
	return 0;
}

static void add_dquot_ref(struct super_block *sb, short type)
{
	struct list_head *p;

	if (!sb->dq_op)
		return;	/* nothing to do */

restart:
	file_list_lock();
	for (p = sb->s_files.next; p != &sb->s_files; p = p->next) {
		struct file *filp = list_entry(p, struct file, f_list);
		struct inode *inode = filp->f_dentry->d_inode;
		if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
			struct vfsmount *mnt = mntget(filp->f_vfsmnt);
			struct dentry *dentry = dget(filp->f_dentry);
			file_list_unlock();
			sb->dq_op->initialize(inode, type);
			dput(dentry);
			mntput(mnt);
			/* As we may have blocked we had better restart... */
			goto restart;
		}
	}
	file_list_unlock();
}

/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
static inline int dqput_blocks(struct dquot *dquot)
{
	if (dquot->dq_count == 1)
		return 1;
	return 0;
}

/* Remove references to dquots from inode - add dquot to list for freeing if needed */
int remove_inode_dquot_ref(struct inode *inode, short type, struct list_head *tofree_head)
{
	struct dquot *dquot = inode->i_dquot[type];
	int cnt;

	inode->i_dquot[type] = NODQUOT;
	/* any other quota in use? */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] != NODQUOT)
			goto put_it;
	}
	inode->i_flags &= ~S_QUOTA;
put_it:
	if (dquot != NODQUOT) {
		if (dqput_blocks(dquot)) {
			if (dquot->dq_count != 1)
				printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", dquot->dq_count);
			list_add(&dquot->dq_free, tofree_head);	/* As dquot must have currently users it can't be on the free list... */
			return 1;
		}
		else
			dqput(dquot);   /* We have guaranteed we won't block */
	}
	return 0;
}

/* Free list of dquots - called from inode.c */
void put_dquot_list(struct list_head *tofree_head)
{
	struct list_head *act_head;
	struct dquot *dquot;

	lock_kernel();
	act_head = tofree_head->next;
	/* So now we have dquots on the list... Just free them */
	while (act_head != tofree_head) {
		dquot = list_entry(act_head, struct dquot, dq_free);
		act_head = act_head->next;
		list_del(&dquot->dq_free);	/* Remove dquot from the list so we won't have problems... */
		INIT_LIST_HEAD(&dquot->dq_free);
		dqput(dquot);
	}
	unlock_kernel();
}

static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
{
	dquot->dq_curinodes += number;
	dquot->dq_flags |= DQ_MOD;
}

static inline void dquot_incr_blocks(struct dquot *dquot, unsigned long number)
{
	dquot->dq_curblocks += number;
	dquot->dq_flags |= DQ_MOD;
}

static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
{
	if (dquot->dq_curinodes > number)
		dquot->dq_curinodes -= number;
	else
		dquot->dq_curinodes = 0;
	if (dquot->dq_curinodes < dquot->dq_isoftlimit)
		dquot->dq_itime = (time_t) 0;
	dquot->dq_flags &= ~DQ_INODES;
	dquot->dq_flags |= DQ_MOD;
}

static inline void dquot_decr_blocks(struct dquot *dquot, unsigned long number)
{
	if (dquot->dq_curblocks > number)
		dquot->dq_curblocks -= number;
	else
		dquot->dq_curblocks = 0;
	if (dquot->dq_curblocks < dquot->dq_bsoftlimit)
		dquot->dq_btime = (time_t) 0;
	dquot->dq_flags &= ~DQ_BLKS;
	dquot->dq_flags |= DQ_MOD;
}

static inline int need_print_warning(struct dquot *dquot, int flag)
{
	switch (dquot->dq_type) {
		case USRQUOTA:
			return current->fsuid == dquot->dq_id && !(dquot->dq_flags & flag);
		case GRPQUOTA:
			return in_group_p(dquot->dq_id) && !(dquot->dq_flags & flag);
	}
	return 0;
}

/* Values of warnings */
#define NOWARN 0
#define IHARDWARN 1
#define ISOFTLONGWARN 2
#define ISOFTWARN 3
#define BHARDWARN 4
#define BSOFTLONGWARN 5
#define BSOFTWARN 6

/* Print warning to user which exceeded quota */
static void print_warning(struct dquot *dquot, const char warntype)
{
	char *msg = NULL;
	int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS :
	  ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES : 0);

	if (!need_print_warning(dquot, flag))
		return;
	dquot->dq_flags |= flag;
	tty_write_message(current->tty, (char *)bdevname(dquot->dq_sb->s_dev));
	if (warntype == ISOFTWARN || warntype == BSOFTWARN)
		tty_write_message(current->tty, ": warning, ");
	else
		tty_write_message(current->tty, ": write failed, ");
	tty_write_message(current->tty, quotatypes[dquot->dq_type]);
	switch (warntype) {
		case IHARDWARN:
			msg = " file limit reached.\n";
			break;
		case ISOFTLONGWARN:
			msg = " file quota exceeded too long.\n";
			break;
		case ISOFTWARN:
			msg = " file quota exceeded.\n";
			break;
		case BHARDWARN:
			msg = " block limit reached.\n";
			break;
		case BSOFTLONGWARN:
			msg = " block quota exceeded too long.\n";
			break;
		case BSOFTWARN:
			msg = " block quota exceeded.\n";
			break;
	}
	tty_write_message(current->tty, msg);
}

static inline void flush_warnings(struct dquot **dquots, char *warntype)
{
	int i;

	for (i = 0; i < MAXQUOTAS; i++)
		if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
			print_warning(dquots[i], warntype[i]);
}

static inline char ignore_hardlimit(struct dquot *dquot)
{
	return capable(CAP_SYS_RESOURCE) && !dquot->dq_sb->s_dquot.rsquash[dquot->dq_type];
}

static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
{
	*warntype = NOWARN;
	if (inodes <= 0 || dquot->dq_flags & DQ_FAKE)
		return QUOTA_OK;

	if (dquot->dq_ihardlimit &&
	   (dquot->dq_curinodes + inodes) > dquot->dq_ihardlimit &&
            !ignore_hardlimit(dquot)) {
		*warntype = IHARDWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_isoftlimit &&
	   (dquot->dq_curinodes + inodes) > dquot->dq_isoftlimit &&
	    dquot->dq_itime && CURRENT_TIME >= dquot->dq_itime &&
            !ignore_hardlimit(dquot)) {
		*warntype = ISOFTLONGWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_isoftlimit &&
	   (dquot->dq_curinodes + inodes) > dquot->dq_isoftlimit &&
	    dquot->dq_itime == 0) {
		*warntype = ISOFTWARN;
		dquot->dq_itime = CURRENT_TIME + dquot->dq_sb->s_dquot.inode_expire[dquot->dq_type];
	}

	return QUOTA_OK;
}

static int check_bdq(struct dquot *dquot, ulong blocks, char prealloc, char *warntype)
{
	*warntype = 0;
	if (blocks <= 0 || dquot->dq_flags & DQ_FAKE)
		return QUOTA_OK;

	if (dquot->dq_bhardlimit &&
	   (dquot->dq_curblocks + blocks) > dquot->dq_bhardlimit &&
            !ignore_hardlimit(dquot)) {
		if (!prealloc)
			*warntype = BHARDWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_bsoftlimit &&
	   (dquot->dq_curblocks + blocks) > dquot->dq_bsoftlimit &&
	    dquot->dq_btime && CURRENT_TIME >= dquot->dq_btime &&
            !ignore_hardlimit(dquot)) {
		if (!prealloc)
			*warntype = BSOFTLONGWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_bsoftlimit &&
	   (dquot->dq_curblocks + blocks) > dquot->dq_bsoftlimit &&
	    dquot->dq_btime == 0) {
		if (!prealloc) {
			*warntype = BSOFTWARN;
			dquot->dq_btime = CURRENT_TIME + dquot->dq_sb->s_dquot.block_expire[dquot->dq_type];
		}
		else
			/*
			 * We don't allow preallocation to exceed softlimit so exceeding will
			 * be always printed
			 */
			return NO_QUOTA;
	}

	return QUOTA_OK;
}

/*
 * Initialize a dquot-struct with new quota info. This is used by the
 * system call interface functions.
 */ 
static int set_dqblk(struct super_block *sb, int id, short type, int flags, struct dqblk *dqblk)
{
	struct dquot *dquot;
	int error = -EFAULT;
	struct dqblk dq_dqblk;

	if (copy_from_user(&dq_dqblk, dqblk, sizeof(struct dqblk)))
		return error;

	if (sb && (dquot = dqget(sb, id, type)) != NODQUOT) {
		/* We can't block while changing quota structure... */
		if (id > 0 && ((flags & SET_QUOTA) || (flags & SET_QLIMIT))) {
			dquot->dq_bhardlimit = dq_dqblk.dqb_bhardlimit;
			dquot->dq_bsoftlimit = dq_dqblk.dqb_bsoftlimit;
			dquot->dq_ihardlimit = dq_dqblk.dqb_ihardlimit;
			dquot->dq_isoftlimit = dq_dqblk.dqb_isoftlimit;
		}

		if ((flags & SET_QUOTA) || (flags & SET_USE)) {
			if (dquot->dq_isoftlimit &&
			    dquot->dq_curinodes < dquot->dq_isoftlimit &&
			    dq_dqblk.dqb_curinodes >= dquot->dq_isoftlimit)
				dquot->dq_itime = CURRENT_TIME + dquot->dq_sb->s_dquot.inode_expire[type];
			dquot->dq_curinodes = dq_dqblk.dqb_curinodes;
			if (dquot->dq_curinodes < dquot->dq_isoftlimit)
				dquot->dq_flags &= ~DQ_INODES;
			if (dquot->dq_bsoftlimit &&
			    dquot->dq_curblocks < dquot->dq_bsoftlimit &&
			    dq_dqblk.dqb_curblocks >= dquot->dq_bsoftlimit)
				dquot->dq_btime = CURRENT_TIME + dquot->dq_sb->s_dquot.block_expire[type];
			dquot->dq_curblocks = dq_dqblk.dqb_curblocks;
			if (dquot->dq_curblocks < dquot->dq_bsoftlimit)
				dquot->dq_flags &= ~DQ_BLKS;
		}

		if (id == 0) {
			dquot->dq_sb->s_dquot.block_expire[type] = dquot->dq_btime = dq_dqblk.dqb_btime;
			dquot->dq_sb->s_dquot.inode_expire[type] = dquot->dq_itime = dq_dqblk.dqb_itime;
		}

		if (dq_dqblk.dqb_bhardlimit == 0 && dq_dqblk.dqb_bsoftlimit == 0 &&
		    dq_dqblk.dqb_ihardlimit == 0 && dq_dqblk.dqb_isoftlimit == 0)
			dquot->dq_flags |= DQ_FAKE;
		else
			dquot->dq_flags &= ~DQ_FAKE;

		dquot->dq_flags |= DQ_MOD;
		dqput(dquot);
	}
	return 0;
}

static int get_quota(struct super_block *sb, int id, short type, struct dqblk *dqblk)
{
	struct dquot *dquot;
	struct dqblk data;
	int error = -ESRCH;

	if (!sb || !sb_has_quota_enabled(sb, type))
		goto out;
	dquot = dqget(sb, id, type);
	if (dquot == NODQUOT)
		goto out;

	memcpy(&data, &dquot->dq_dqb, sizeof(struct dqblk));        /* We copy data to preserve them from changing */
	dqput(dquot);
	error = -EFAULT;
	if (dqblk && !copy_to_user(dqblk, &data, sizeof(struct dqblk)))
		error = 0;
out:
	return error;
}

static int get_stats(caddr_t addr)
{
	int error = -EFAULT;
	struct dqstats stats;

	dqstats.allocated_dquots = nr_dquots;
	dqstats.free_dquots = nr_free_dquots;

	/* make a copy, in case we page-fault in user space */
	memcpy(&stats, &dqstats, sizeof(struct dqstats));
	if (!copy_to_user(addr, &stats, sizeof(struct dqstats)))
		error = 0;
	return error;
}

static int quota_root_squash(struct super_block *sb, short type, int *addr)
{
	int new_value, error;

	if (!sb)
		return(-ENODEV);

	error = -EFAULT;
	if (!copy_from_user(&new_value, addr, sizeof(int))) {
		sb_dqopt(sb)->rsquash[type] = new_value;
		error = 0;
	}
	return error;
}

#if 0	/* We are not going to support filesystems without i_blocks... */
/*
 * This is a simple algorithm that calculates the size of a file in blocks.
 * This is only used on filesystems that do not have an i_blocks count.
 */
static u_long isize_to_blocks(loff_t isize, size_t blksize_bits)
{
	u_long blocks;
	u_long indirect;

	if (!blksize_bits)
		blksize_bits = BLOCK_SIZE_BITS;
	blocks = (isize >> blksize_bits) + ((isize & ~((1 << blksize_bits)-1)) ? 1 : 0);
	if (blocks > 10) {
		indirect = ((blocks - 11) >> 8) + 1; /* single indirect blocks */
		if (blocks > (10 + 256)) {
			indirect += ((blocks - 267) >> 16) + 1; /* double indirect blocks */
			if (blocks > (10 + 256 + (256 << 8)))
				indirect++; /* triple indirect blocks */
		}
		blocks += indirect;
	}
	return blocks;
}
#endif

/*
 * Externally referenced functions through dquot_operations in inode.
 *
 * Note: this is a blocking operation.
 */
void dquot_initialize(struct inode *inode, short type)
{
	struct dquot *dquot[MAXQUOTAS];
	unsigned int id = 0;
	short cnt;

	if (IS_NOQUOTA(inode))
		return;
	/* Build list of quotas to initialize... We can block here */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		dquot[cnt] = NODQUOT;
		if (type != -1 && cnt != type)
			continue;
		if (!sb_has_quota_enabled(inode->i_sb, cnt))
			continue;
		if (inode->i_dquot[cnt] == NODQUOT) {
			switch (cnt) {
				case USRQUOTA:
					id = inode->i_uid;
					break;
				case GRPQUOTA:
					id = inode->i_gid;
					break;
			}
			dquot[cnt] = dqget(inode->i_sb, id, cnt);
		}
	}
	/* NOBLOCK START: Here we shouldn't block */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (dquot[cnt] == NODQUOT || !sb_has_quota_enabled(inode->i_sb, cnt) || inode->i_dquot[cnt] != NODQUOT)
			continue;
		inode->i_dquot[cnt] = dquot[cnt];
		dquot[cnt] = NODQUOT;