Fixed MTP to work with TWRP

fs/quota/Kconfig

@@ -0,0 +1,75 @@
+#
+#  Quota configuration
+#
+
+config QUOTA
+	bool "Quota support"
+	select QUOTACTL
+	help
+	  If you say Y here, you will be able to set per user limits for disk
+	  usage (also called disk quotas). Currently, it works for the
+	  ext2, ext3, ext4, jfs, ocfs2 and reiserfs file systems.
+	  Note that gfs2 and xfs use their own quota system.
+	  Ext3, ext4 and reiserfs also support journaled quotas for which
+	  you don't need to run quotacheck(8) after an unclean shutdown.
+	  For further details, read the Quota mini-HOWTO, available from
+	  <http://www.tldp.org/docs.html#howto>, or the documentation provided
+	  with the quota tools. Probably the quota support is only useful for
+	  multi user systems. If unsure, say N.
+
+config QUOTA_NETLINK_INTERFACE
+	bool "Report quota messages through netlink interface"
+	depends on QUOTACTL && NET
+	help
+	  If you say Y here, quota warnings (about exceeding softlimit, reaching
+	  hardlimit, etc.) will be reported through netlink interface. If unsure,
+	  say Y.
+
+config PRINT_QUOTA_WARNING
+	bool "Print quota warnings to console (OBSOLETE)"
+	depends on QUOTA
+	default y
+	help
+	  If you say Y here, quota warnings (about exceeding softlimit, reaching
+	  hardlimit, etc.) will be printed to the process' controlling terminal.
+	  Note that this behavior is currently deprecated and may go away in
+	  future. Please use notification via netlink socket instead.
+
+config QUOTA_DEBUG
+	bool "Additional quota sanity checks"
+	depends on QUOTA
+	default n
+	help
+	  If you say Y here, quota subsystem will perform some additional
+	  sanity checks of quota internal structures. If unsure, say N.
+
+# Generic support for tree structured quota files. Selected when needed.
+config QUOTA_TREE
+	 tristate
+
+config QFMT_V1
+	tristate "Old quota format support"
+	depends on QUOTA
+	help
+	  This quota format was (is) used by kernels earlier than 2.4.22. If
+	  you have quota working and you don't want to convert to new quota
+	  format say Y here.
+
+config QFMT_V2
+	tristate "Quota format vfsv0 and vfsv1 support"
+	depends on QUOTA
+	select QUOTA_TREE
+	help
+	  This config option enables kernel support for vfsv0 and vfsv1 quota
+	  formats. Both these formats support 32-bit UIDs/GIDs and vfsv1 format
+	  also supports 64-bit inode and block quota limits. If you need this
+	  functionality say Y here.
+
+config QUOTACTL
+	bool
+	default n
+
+config QUOTACTL_COMPAT
+	bool
+	depends on QUOTACTL && COMPAT_FOR_U64_ALIGNMENT
+	default y

fs/quota/Makefile

@@ -0,0 +1,7 @@
+obj-$(CONFIG_QUOTA)		+= dquot.o
+obj-$(CONFIG_QFMT_V1)		+= quota_v1.o
+obj-$(CONFIG_QFMT_V2)		+= quota_v2.o
+obj-$(CONFIG_QUOTA_TREE)	+= quota_tree.o
+obj-$(CONFIG_QUOTACTL)		+= quota.o kqid.o
+obj-$(CONFIG_QUOTACTL_COMPAT)	+= compat.o
+obj-$(CONFIG_QUOTA_NETLINK_INTERFACE)	+= netlink.o

fs/quota/compat.c

@@ -0,0 +1,118 @@
+
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <linux/quotaops.h>
+
+/*
+ * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
+ * and is necessary due to alignment problems.
+ */
+struct compat_if_dqblk {
+	compat_u64 dqb_bhardlimit;
+	compat_u64 dqb_bsoftlimit;
+	compat_u64 dqb_curspace;
+	compat_u64 dqb_ihardlimit;
+	compat_u64 dqb_isoftlimit;
+	compat_u64 dqb_curinodes;
+	compat_u64 dqb_btime;
+	compat_u64 dqb_itime;
+	compat_uint_t dqb_valid;
+};
+
+/* XFS structures */
+struct compat_fs_qfilestat {
+	compat_u64 dqb_bhardlimit;
+	compat_u64 qfs_nblks;
+	compat_uint_t qfs_nextents;
+};
+
+struct compat_fs_quota_stat {
+	__s8		qs_version;
+	__u16		qs_flags;
+	__s8		qs_pad;
+	struct compat_fs_qfilestat	qs_uquota;
+	struct compat_fs_qfilestat	qs_gquota;
+	compat_uint_t	qs_incoredqs;
+	compat_int_t	qs_btimelimit;
+	compat_int_t	qs_itimelimit;
+	compat_int_t	qs_rtbtimelimit;
+	__u16		qs_bwarnlimit;
+	__u16		qs_iwarnlimit;
+};
+
+asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
+						qid_t id, void __user *addr)
+{
+	unsigned int cmds;
+	struct if_dqblk __user *dqblk;
+	struct compat_if_dqblk __user *compat_dqblk;
+	struct fs_quota_stat __user *fsqstat;
+	struct compat_fs_quota_stat __user *compat_fsqstat;
+	compat_uint_t data;
+	u16 xdata;
+	long ret;
+
+	cmds = cmd >> SUBCMDSHIFT;
+
+	switch (cmds) {
+	case Q_GETQUOTA:
+		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
+		compat_dqblk = addr;
+		ret = sys_quotactl(cmd, special, id, dqblk);
+		if (ret)
+			break;
+		if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
+			get_user(data, &dqblk->dqb_valid) ||
+			put_user(data, &compat_dqblk->dqb_valid))
+			ret = -EFAULT;
+		break;
+	case Q_SETQUOTA:
+		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
+		compat_dqblk = addr;
+		ret = -EFAULT;
+		if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
+			get_user(data, &compat_dqblk->dqb_valid) ||
+			put_user(data, &dqblk->dqb_valid))
+			break;
+		ret = sys_quotactl(cmd, special, id, dqblk);
+		break;
+	case Q_XGETQSTAT:
+		fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
+		compat_fsqstat = addr;
+		ret = sys_quotactl(cmd, special, id, fsqstat);
+		if (ret)
+			break;
+		ret = -EFAULT;
+		/* Copying qs_version, qs_flags, qs_pad */
+		if (copy_in_user(compat_fsqstat, fsqstat,
+			offsetof(struct compat_fs_quota_stat, qs_uquota)))
+			break;
+		/* Copying qs_uquota */
+		if (copy_in_user(&compat_fsqstat->qs_uquota,
+			&fsqstat->qs_uquota,
+			sizeof(compat_fsqstat->qs_uquota)) ||
+			get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
+			put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
+			break;
+		/* Copying qs_gquota */
+		if (copy_in_user(&compat_fsqstat->qs_gquota,
+			&fsqstat->qs_gquota,
+			sizeof(compat_fsqstat->qs_gquota)) ||
+			get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
+			put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
+			break;
+		/* Copying the rest */
+		if (copy_in_user(&compat_fsqstat->qs_incoredqs,
+			&fsqstat->qs_incoredqs,
+			sizeof(struct compat_fs_quota_stat) -
+			offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
+			get_user(xdata, &fsqstat->qs_iwarnlimit) ||
+			put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
+			break;
+		ret = 0;
+		break;
+	default:
+		ret = sys_quotactl(cmd, special, id, addr);
+	}
+	return ret;
+}

fs/quota/kqid.c

@@ -0,0 +1,132 @@
+#include <linux/fs.h>
+#include <linux/quota.h>
+#include <linux/export.h>
+
+/**
+ *	qid_eq - Test to see if to kquid values are the same
+ *	@left: A qid value
+ *	@right: Another quid value
+ *
+ *	Return true if the two qid values are equal and false otherwise.
+ */
+bool qid_eq(struct kqid left, struct kqid right)
+{
+	if (left.type != right.type)
+		return false;
+	switch(left.type) {
+	case USRQUOTA:
+		return uid_eq(left.uid, right.uid);
+	case GRPQUOTA:
+		return gid_eq(left.gid, right.gid);
+	case PRJQUOTA:
+		return projid_eq(left.projid, right.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(qid_eq);
+
+/**
+ *	qid_lt - Test to see if one qid value is less than another
+ *	@left: The possibly lesser qid value
+ *	@right: The possibly greater qid value
+ *
+ *	Return true if left is less than right and false otherwise.
+ */
+bool qid_lt(struct kqid left, struct kqid right)
+{
+	if (left.type < right.type)
+		return true;
+	if (left.type > right.type)
+		return false;
+	switch (left.type) {
+	case USRQUOTA:
+		return uid_lt(left.uid, right.uid);
+	case GRPQUOTA:
+		return gid_lt(left.gid, right.gid);
+	case PRJQUOTA:
+		return projid_lt(left.projid, right.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(qid_lt);
+
+/**
+ *	from_kqid - Create a qid from a kqid user-namespace pair.
+ *	@targ: The user namespace we want a qid in.
+ *	@kqid: The kernel internal quota identifier to start with.
+ *
+ *	Map @kqid into the user-namespace specified by @targ and
+ *	return the resulting qid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	If @kqid has no mapping in @targ (qid_t)-1 is returned.
+ */
+qid_t from_kqid(struct user_namespace *targ, struct kqid kqid)
+{
+	switch (kqid.type) {
+	case USRQUOTA:
+		return from_kuid(targ, kqid.uid);
+	case GRPQUOTA:
+		return from_kgid(targ, kqid.gid);
+	case PRJQUOTA:
+		return from_kprojid(targ, kqid.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(from_kqid);
+
+/**
+ *	from_kqid_munged - Create a qid from a kqid user-namespace pair.
+ *	@targ: The user namespace we want a qid in.
+ *	@kqid: The kernel internal quota identifier to start with.
+ *
+ *	Map @kqid into the user-namespace specified by @targ and
+ *	return the resulting qid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	Unlike from_kqid from_kqid_munged never fails and always
+ *	returns a valid projid.  This makes from_kqid_munged
+ *	appropriate for use in places where failing to provide
+ *	a qid_t is not a good option.
+ *
+ *	If @kqid has no mapping in @targ the kqid.type specific
+ *	overflow identifier is returned.
+ */
+qid_t from_kqid_munged(struct user_namespace *targ, struct kqid kqid)
+{
+	switch (kqid.type) {
+	case USRQUOTA:
+		return from_kuid_munged(targ, kqid.uid);
+	case GRPQUOTA:
+		return from_kgid_munged(targ, kqid.gid);
+	case PRJQUOTA:
+		return from_kprojid_munged(targ, kqid.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(from_kqid_munged);
+
+/**
+ *	qid_valid - Report if a valid value is stored in a kqid.
+ *	@qid: The kernel internal quota identifier to test.
+ */
+bool qid_valid(struct kqid qid)
+{
+	switch (qid.type) {
+	case USRQUOTA:
+		return uid_valid(qid.uid);
+	case GRPQUOTA:
+		return gid_valid(qid.gid);
+	case PRJQUOTA:
+		return projid_valid(qid.projid);
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(qid_valid);

fs/quota/netlink.c

@@ -0,0 +1,109 @@
+
+#include <linux/cred.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/quotaops.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+static const struct genl_multicast_group quota_mcgrps[] = {
+	{ .name = "events", },
+};
+
+/* Netlink family structure for quota */
+static struct genl_family quota_genl_family = {
+	/*
+	 * Needed due to multicast group ID abuse - old code assumed
+	 * the family ID was also a valid multicast group ID (which
+	 * isn't true) and userspace might thus rely on it. Assign a
+	 * static ID for this group to make dealing with that easier.
+	 */
+	.id = GENL_ID_VFS_DQUOT,
+	.hdrsize = 0,
+	.name = "VFS_DQUOT",
+	.version = 1,
+	.maxattr = QUOTA_NL_A_MAX,
+	.mcgrps = quota_mcgrps,
+	.n_mcgrps = ARRAY_SIZE(quota_mcgrps),
+};
+
+/**
+ * quota_send_warning - Send warning to userspace about exceeded quota
+ * @qid: The kernel internal quota identifier.
+ * @dev: The device on which the fs is mounted (sb->s_dev)
+ * @warntype: The type of the warning: QUOTA_NL_...
+ *
+ * This can be used by filesystems (including those which don't use
+ * dquot) to send a message to userspace relating to quota limits.
+ *
+ */
+
+void quota_send_warning(struct kqid qid, dev_t dev,
+			const char warntype)
+{
+	static atomic_t seq;
+	struct sk_buff *skb;
+	void *msg_head;
+	int ret;
+	int msg_size = 4 * nla_total_size(sizeof(u32)) +
+		       2 * nla_total_size(sizeof(u64));
+
+	/* We have to allocate using GFP_NOFS as we are called from a
+	 * filesystem performing write and thus further recursion into
+	 * the fs to free some data could cause deadlocks. */
+	skb = genlmsg_new(msg_size, GFP_NOFS);
+	if (!skb) {
+		printk(KERN_ERR
+		  "VFS: Not enough memory to send quota warning.\n");
+		return;
+	}
+	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
+			&quota_genl_family, 0, QUOTA_NL_C_WARNING);
+	if (!msg_head) {
+		printk(KERN_ERR
+		  "VFS: Cannot store netlink header in quota warning.\n");
+		goto err_out;
+	}
+	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
+			  from_kqid_munged(&init_user_ns, qid));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
+			  from_kuid_munged(&init_user_ns, current_uid()));
+	if (ret)
+		goto attr_err_out;
+	genlmsg_end(skb, msg_head);
+
+	genlmsg_multicast(&quota_genl_family, skb, 0, 0, GFP_NOFS);
+	return;
+attr_err_out:
+	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
+err_out:
+	kfree_skb(skb);
+}
+EXPORT_SYMBOL(quota_send_warning);
+
+static int __init quota_init(void)
+{
+	if (genl_register_family(&quota_genl_family) != 0)
+		printk(KERN_ERR
+		       "VFS: Failed to create quota netlink interface.\n");
+	return 0;
+};
+
+module_init(quota_init);

fs/quota/quota.c

@@ -0,0 +1,568 @@
+/*
+ * Quota code necessary even when VFS quota support is not compiled
+ * into the kernel.  The interesting stuff is over in dquot.c, here
+ * we have symbols for initial quotactl(2) handling, the sysctl(2)
+ * variables, etc - things needed even when quota support disabled.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <asm/current.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/capability.h>
+#include <linux/quotaops.h>
+#include <linux/types.h>
+#include <linux/writeback.h>
+
+static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
+				     qid_t id)
+{
+	switch (cmd) {
+	/* these commands do not require any special privilegues */
+	case Q_GETFMT:
+	case Q_SYNC:
+	case Q_GETINFO:
+	case Q_XGETQSTAT:
+	case Q_XGETQSTATV:
+	case Q_XQUOTASYNC:
+		break;
+	/* allow to query information for dquots we "own" */
+	case Q_GETQUOTA:
+	case Q_XGETQUOTA:
+		if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
+		    (type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
+			break;
+		/*FALLTHROUGH*/
+	default:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+	}
+
+	return security_quotactl(cmd, type, id, sb);
+}
+
+static void quota_sync_one(struct super_block *sb, void *arg)
+{
+	if (sb->s_qcop && sb->s_qcop->quota_sync)
+		sb->s_qcop->quota_sync(sb, *(int *)arg);
+}
+
+static int quota_sync_all(int type)
+{
+	int ret;
+
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+	ret = security_quotactl(Q_SYNC, type, 0, NULL);
+	if (!ret)
+		iterate_supers(quota_sync_one, &type);
+	return ret;
+}
+
+static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
+		         struct path *path)
+{
+	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
+		return -ENOSYS;
+	if (sb->s_qcop->quota_on_meta)
+		return sb->s_qcop->quota_on_meta(sb, type, id);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	return sb->s_qcop->quota_on(sb, type, id, path);
+}
+
+static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
+{
+	__u32 fmt;
+
+	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
+	if (!sb_has_quota_active(sb, type)) {
+		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+		return -ESRCH;
+	}
+	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
+	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+	if (copy_to_user(addr, &fmt, sizeof(fmt)))
+		return -EFAULT;
+	return 0;
+}
+
+static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
+{
+	struct if_dqinfo info;
+	int ret;
+
+	if (!sb->s_qcop->get_info)
+		return -ENOSYS;
+	ret = sb->s_qcop->get_info(sb, type, &info);
+	if (!ret && copy_to_user(addr, &info, sizeof(info)))
+		return -EFAULT;
+	return ret;
+}
+
+static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
+{
+	struct if_dqinfo info;
+
+	if (copy_from_user(&info, addr, sizeof(info)))
+		return -EFAULT;
+	if (!sb->s_qcop->set_info)
+		return -ENOSYS;
+	return sb->s_qcop->set_info(sb, type, &info);
+}
+
+static inline qsize_t qbtos(qsize_t blocks)
+{
+	return blocks << QIF_DQBLKSIZE_BITS;
+}
+
+static inline qsize_t stoqb(qsize_t space)
+{
+	return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
+}
+
+static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
+{
+	memset(dst, 0, sizeof(*dst));
+	dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
+	dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
+	dst->dqb_curspace = src->d_space;
+	dst->dqb_ihardlimit = src->d_ino_hardlimit;
+	dst->dqb_isoftlimit = src->d_ino_softlimit;
+	dst->dqb_curinodes = src->d_ino_count;
+	dst->dqb_btime = src->d_spc_timer;
+	dst->dqb_itime = src->d_ino_timer;
+	dst->dqb_valid = QIF_ALL;
+}
+
+static int quota_getquota(struct super_block *sb, int type, qid_t id,
+			  void __user *addr)
+{
+	struct kqid qid;
+	struct qc_dqblk fdq;
+	struct if_dqblk idq;
+	int ret;
+
+	if (!sb->s_qcop->get_dqblk)
+		return -ENOSYS;
+	qid = make_kqid(current_user_ns(), type, id);
+	if (!qid_valid(qid))
+		return -EINVAL;
+	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
+	if (ret)
+		return ret;
+	copy_to_if_dqblk(&idq, &fdq);
+	if (copy_to_user(addr, &idq, sizeof(idq)))
+		return -EFAULT;
+	return 0;
+}
+
+static void copy_from_if_dqblk(struct qc_dqblk *dst, struct if_dqblk *src)
+{
+	dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
+	dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
+	dst->d_space = src->dqb_curspace;
+	dst->d_ino_hardlimit = src->dqb_ihardlimit;
+	dst->d_ino_softlimit = src->dqb_isoftlimit;
+	dst->d_ino_count = src->dqb_curinodes;
+	dst->d_spc_timer = src->dqb_btime;
+	dst->d_ino_timer = src->dqb_itime;
+
+	dst->d_fieldmask = 0;
+	if (src->dqb_valid & QIF_BLIMITS)
+		dst->d_fieldmask |= QC_SPC_SOFT | QC_SPC_HARD;
+	if (src->dqb_valid & QIF_SPACE)
+		dst->d_fieldmask |= QC_SPACE;
+	if (src->dqb_valid & QIF_ILIMITS)
+		dst->d_fieldmask |= QC_INO_SOFT | QC_INO_HARD;
+	if (src->dqb_valid & QIF_INODES)
+		dst->d_fieldmask |= QC_INO_COUNT;
+	if (src->dqb_valid & QIF_BTIME)
+		dst->d_fieldmask |= QC_SPC_TIMER;
+	if (src->dqb_valid & QIF_ITIME)
+		dst->d_fieldmask |= QC_INO_TIMER;
+}
+
+static int quota_setquota(struct super_block *sb, int type, qid_t id,
+			  void __user *addr)
+{
+	struct qc_dqblk fdq;
+	struct if_dqblk idq;
+	struct kqid qid;
+
+	if (copy_from_user(&idq, addr, sizeof(idq)))
+		return -EFAULT;
+	if (!sb->s_qcop->set_dqblk)
+		return -ENOSYS;
+	qid = make_kqid(current_user_ns(), type, id);
+	if (!qid_valid(qid))
+		return -EINVAL;
+	copy_from_if_dqblk(&fdq, &idq);
+	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
+}
+
+static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
+{
+	__u32 flags;
+
+	if (copy_from_user(&flags, addr, sizeof(flags)))
+		return -EFAULT;
+	if (!sb->s_qcop->set_xstate)
+		return -ENOSYS;
+	return sb->s_qcop->set_xstate(sb, flags, cmd);
+}
+
+static int quota_getxstate(struct super_block *sb, void __user *addr)
+{
+	struct fs_quota_stat fqs;
+	int ret;
+
+	if (!sb->s_qcop->get_xstate)
+		return -ENOSYS;
+	ret = sb->s_qcop->get_xstate(sb, &fqs);
+	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
+		return -EFAULT;
+	return ret;
+}
+
+static int quota_getxstatev(struct super_block *sb, void __user *addr)
+{
+	struct fs_quota_statv fqs;
+	int ret;
+
+	if (!sb->s_qcop->get_xstatev)
+		return -ENOSYS;
+
+	memset(&fqs, 0, sizeof(fqs));
+	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
+		return -EFAULT;
+
+	/* If this kernel doesn't support user specified version, fail */
+	switch (fqs.qs_version) {
+	case FS_QSTATV_VERSION1:
+		break;
+	default:
+		return -EINVAL;
+	}
+	ret = sb->s_qcop->get_xstatev(sb, &fqs);
+	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
+		return -EFAULT;
+	return ret;
+}
+
+/*
+ * XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
+ * out of there as xfsprogs rely on definitions being in that header file. So
+ * just define same functions here for quota purposes.
+ */
+#define XFS_BB_SHIFT 9
+
+static inline u64 quota_bbtob(u64 blocks)
+{
+	return blocks << XFS_BB_SHIFT;
+}
+
+static inline u64 quota_btobb(u64 bytes)
+{
+	return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
+}
+
+static void copy_from_xfs_dqblk(struct qc_dqblk *dst, struct fs_disk_quota *src)
+{
+	dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
+	dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
+	dst->d_ino_hardlimit = src->d_ino_hardlimit;
+	dst->d_ino_softlimit = src->d_ino_softlimit;
+	dst->d_space = quota_bbtob(src->d_bcount);
+	dst->d_ino_count = src->d_icount;
+	dst->d_ino_timer = src->d_itimer;
+	dst->d_spc_timer = src->d_btimer;
+	dst->d_ino_warns = src->d_iwarns;
+	dst->d_spc_warns = src->d_bwarns;
+	dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
+	dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
+	dst->d_rt_space = quota_bbtob(src->d_rtbcount);
+	dst->d_rt_spc_timer = src->d_rtbtimer;
+	dst->d_rt_spc_warns = src->d_rtbwarns;
+	dst->d_fieldmask = 0;
+	if (src->d_fieldmask & FS_DQ_ISOFT)
+		dst->d_fieldmask |= QC_INO_SOFT;
+	if (src->d_fieldmask & FS_DQ_IHARD)
+		dst->d_fieldmask |= QC_INO_HARD;
+	if (src->d_fieldmask & FS_DQ_BSOFT)
+		dst->d_fieldmask |= QC_SPC_SOFT;
+	if (src->d_fieldmask & FS_DQ_BHARD)
+		dst->d_fieldmask |= QC_SPC_HARD;
+	if (src->d_fieldmask & FS_DQ_RTBSOFT)
+		dst->d_fieldmask |= QC_RT_SPC_SOFT;
+	if (src->d_fieldmask & FS_DQ_RTBHARD)
+		dst->d_fieldmask |= QC_RT_SPC_HARD;
+	if (src->d_fieldmask & FS_DQ_BTIMER)
+		dst->d_fieldmask |= QC_SPC_TIMER;
+	if (src->d_fieldmask & FS_DQ_ITIMER)
+		dst->d_fieldmask |= QC_INO_TIMER;
+	if (src->d_fieldmask & FS_DQ_RTBTIMER)
+		dst->d_fieldmask |= QC_RT_SPC_TIMER;
+	if (src->d_fieldmask & FS_DQ_BWARNS)
+		dst->d_fieldmask |= QC_SPC_WARNS;
+	if (src->d_fieldmask & FS_DQ_IWARNS)
+		dst->d_fieldmask |= QC_INO_WARNS;
+	if (src->d_fieldmask & FS_DQ_RTBWARNS)
+		dst->d_fieldmask |= QC_RT_SPC_WARNS;
+	if (src->d_fieldmask & FS_DQ_BCOUNT)
+		dst->d_fieldmask |= QC_SPACE;
+	if (src->d_fieldmask & FS_DQ_ICOUNT)
+		dst->d_fieldmask |= QC_INO_COUNT;
+	if (src->d_fieldmask & FS_DQ_RTBCOUNT)
+		dst->d_fieldmask |= QC_RT_SPACE;
+}
+
+static int quota_setxquota(struct super_block *sb, int type, qid_t id,
+			   void __user *addr)
+{
+	struct fs_disk_quota fdq;
+	struct qc_dqblk qdq;
+	struct kqid qid;
+
+	if (copy_from_user(&fdq, addr, sizeof(fdq)))
+		return -EFAULT;
+	if (!sb->s_qcop->set_dqblk)
+		return -ENOSYS;
+	qid = make_kqid(current_user_ns(), type, id);
+	if (!qid_valid(qid))
+		return -EINVAL;
+	copy_from_xfs_dqblk(&qdq, &fdq);
+	return sb->s_qcop->set_dqblk(sb, qid, &qdq);
+}
+
+static void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
+			      int type, qid_t id)
+{
+	memset(dst, 0, sizeof(*dst));
+	dst->d_version = FS_DQUOT_VERSION;
+	dst->d_id = id;
+	if (type == USRQUOTA)
+		dst->d_flags = FS_USER_QUOTA;
+	else if (type == PRJQUOTA)
+		dst->d_flags = FS_PROJ_QUOTA;
+	else
+		dst->d_flags = FS_GROUP_QUOTA;
+	dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
+	dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
+	dst->d_ino_hardlimit = src->d_ino_hardlimit;
+	dst->d_ino_softlimit = src->d_ino_softlimit;
+	dst->d_bcount = quota_btobb(src->d_space);
+	dst->d_icount = src->d_ino_count;
+	dst->d_itimer = src->d_ino_timer;
+	dst->d_btimer = src->d_spc_timer;
+	dst->d_iwarns = src->d_ino_warns;
+	dst->d_bwarns = src->d_spc_warns;
+	dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
+	dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
+	dst->d_rtbcount = quota_btobb(src->d_rt_space);
+	dst->d_rtbtimer = src->d_rt_spc_timer;
+	dst->d_rtbwarns = src->d_rt_spc_warns;
+}
+
+static int quota_getxquota(struct super_block *sb, int type, qid_t id,
+			   void __user *addr)
+{
+	struct fs_disk_quota fdq;
+	struct qc_dqblk qdq;
+	struct kqid qid;
+	int ret;
+
+	if (!sb->s_qcop->get_dqblk)
+		return -ENOSYS;
+	qid = make_kqid(current_user_ns(), type, id);
+	if (!qid_valid(qid))
+		return -EINVAL;
+	ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
+	if (ret)
+		return ret;
+	copy_to_xfs_dqblk(&fdq, &qdq, type, id);
+	if (copy_to_user(addr, &fdq, sizeof(fdq)))
+		return -EFAULT;
+	return ret;
+}
+
+static int quota_rmxquota(struct super_block *sb, void __user *addr)
+{
+	__u32 flags;
+
+	if (copy_from_user(&flags, addr, sizeof(flags)))
+		return -EFAULT;
+	if (!sb->s_qcop->rm_xquota)
+		return -ENOSYS;
+	return sb->s_qcop->rm_xquota(sb, flags);
+}
+
+/* Copy parameters and call proper function */
+static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
+		       void __user *addr, struct path *path)
+{
+	int ret;
+
+	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
+		return -EINVAL;
+	if (!sb->s_qcop)
+		return -ENOSYS;
+
+	ret = check_quotactl_permission(sb, type, cmd, id);
+	if (ret < 0)
+		return ret;
+
+	switch (cmd) {
+	case Q_QUOTAON:
+		return quota_quotaon(sb, type, cmd, id, path);
+	case Q_QUOTAOFF:
+		if (!sb->s_qcop->quota_off)
+			return -ENOSYS;
+		return sb->s_qcop->quota_off(sb, type);
+	case Q_GETFMT:
+		return quota_getfmt(sb, type, addr);
+	case Q_GETINFO:
+		return quota_getinfo(sb, type, addr);
+	case Q_SETINFO:
+		return quota_setinfo(sb, type, addr);
+	case Q_GETQUOTA:
+		return quota_getquota(sb, type, id, addr);
+	case Q_SETQUOTA:
+		return quota_setquota(sb, type, id, addr);
+	case Q_SYNC:
+		if (!sb->s_qcop->quota_sync)
+			return -ENOSYS;
+		return sb->s_qcop->quota_sync(sb, type);
+	case Q_XQUOTAON:
+	case Q_XQUOTAOFF:
+		return quota_setxstate(sb, cmd, addr);
+	case Q_XQUOTARM:
+		return quota_rmxquota(sb, addr);
+	case Q_XGETQSTAT:
+		return quota_getxstate(sb, addr);
+	case Q_XGETQSTATV:
+		return quota_getxstatev(sb, addr);
+	case Q_XSETQLIM:
+		return quota_setxquota(sb, type, id, addr);
+	case Q_XGETQUOTA:
+		return quota_getxquota(sb, type, id, addr);
+	case Q_XQUOTASYNC:
+		if (sb->s_flags & MS_RDONLY)
+			return -EROFS;
+		/* XFS quotas are fully coherent now, making this call a noop */
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+#ifdef CONFIG_BLOCK
+
+/* Return 1 if 'cmd' will block on frozen filesystem */
+static int quotactl_cmd_write(int cmd)
+{
+	switch (cmd) {
+	case Q_GETFMT:
+	case Q_GETINFO:
+	case Q_SYNC:
+	case Q_XGETQSTAT:
+	case Q_XGETQSTATV:
+	case Q_XGETQUOTA:
+	case Q_XQUOTASYNC:
+		return 0;
+	}
+	return 1;
+}
+
+#endif /* CONFIG_BLOCK */
+
+/*
+ * look up a superblock on which quota ops will be performed
+ * - use the name of a block device to find the superblock thereon
+ */
+static struct super_block *quotactl_block(const char __user *special, int cmd)
+{
+#ifdef CONFIG_BLOCK
+	struct block_device *bdev;
+	struct super_block *sb;
+	struct filename *tmp = getname(special);
+
+	if (IS_ERR(tmp))
+		return ERR_CAST(tmp);
+	bdev = lookup_bdev(tmp->name);
+	putname(tmp);
+	if (IS_ERR(bdev))
+		return ERR_CAST(bdev);
+	if (quotactl_cmd_write(cmd))
+		sb = get_super_thawed(bdev);
+	else
+		sb = get_super(bdev);
+	bdput(bdev);
+	if (!sb)
+		return ERR_PTR(-ENODEV);
+
+	return sb;
+#else
+	return ERR_PTR(-ENODEV);
+#endif
+}
+
+/*
+ * This is the system call interface. This communicates with
+ * the user-level programs. Currently this only supports diskquota
+ * calls. Maybe we need to add the process quotas etc. in the future,
+ * but we probably should use rlimits for that.
+ */
+SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
+		qid_t, id, void __user *, addr)
+{
+	uint cmds, type;
+	struct super_block *sb = NULL;
+	struct path path, *pathp = NULL;
+	int ret;
+
+	cmds = cmd >> SUBCMDSHIFT;
+	type = cmd & SUBCMDMASK;
+
+	/*
+	 * As a special case Q_SYNC can be called without a specific device.
+	 * It will iterate all superblocks that have quota enabled and call
+	 * the sync action on each of them.
+	 */
+	if (!special) {
+		if (cmds == Q_SYNC)
+			return quota_sync_all(type);
+		return -ENODEV;
+	}
+
+	/*
+	 * Path for quotaon has to be resolved before grabbing superblock
+	 * because that gets s_umount sem which is also possibly needed by path
+	 * resolution (think about autofs) and thus deadlocks could arise.
+	 */
+	if (cmds == Q_QUOTAON) {
+		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
+		if (ret)
+			pathp = ERR_PTR(ret);
+		else
+			pathp = &path;
+	}
+
+	sb = quotactl_block(special, cmds);
+	if (IS_ERR(sb)) {
+		ret = PTR_ERR(sb);
+		goto out;
+	}
+
+	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
+
+	drop_super(sb);
+out:
+	if (pathp && !IS_ERR(pathp))
+		path_put(pathp);
+	return ret;
+}

fs/quota/quota_tree.c

@@ -0,0 +1,663 @@
+/*
+ *	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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/quotaops.h>
+
+#include <asm/byteorder.h>
+
+#include "quota_tree.h"
+
+MODULE_AUTHOR("Jan Kara");
+MODULE_DESCRIPTION("Quota trie support");
+MODULE_LICENSE("GPL");
+
+#define __QUOTA_QT_PARANOIA
+
+static int get_index(struct qtree_mem_dqinfo *info, struct kqid qid, int depth)
+{
+	unsigned int epb = info->dqi_usable_bs >> 2;
+	qid_t id = from_kqid(&init_user_ns, qid);
+
+	depth = info->dqi_qtree_depth - depth - 1;
+	while (depth--)
+		id /= epb;
+	return id % epb;
+}
+
+/* Number of entries in one blocks */
+static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
+{
+	return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader))
+	       / info->dqi_entry_size;
+}
+
+static char *getdqbuf(size_t size)
+{
+	char *buf = kmalloc(size, GFP_NOFS);
+	if (!buf)
+		printk(KERN_WARNING
+		       "VFS: Not enough memory for quota buffers.\n");
+	return buf;
+}
+
+static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
+{
+	struct super_block *sb = info->dqi_sb;
+
+	memset(buf, 0, info->dqi_usable_bs);
+	return sb->s_op->quota_read(sb, info->dqi_type, buf,
+	       info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
+}
+
+static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
+{
+	struct super_block *sb = info->dqi_sb;
+	ssize_t ret;
+
+	ret = sb->s_op->quota_write(sb, info->dqi_type, buf,
+	       info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
+	if (ret != info->dqi_usable_bs) {
+		quota_error(sb, "dquota write failed");
+		if (ret >= 0)
+			ret = -EIO;
+	}
+	return ret;
+}
+
+/* Remove empty block from list and return it */
+static int get_free_dqblk(struct qtree_mem_dqinfo *info)
+{
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
+	int ret, blk;
+
+	if (!buf)
+		return -ENOMEM;
+	if (info->dqi_free_blk) {
+		blk = info->dqi_free_blk;
+		ret = read_blk(info, blk, buf);
+		if (ret < 0)
+			goto out_buf;
+		info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
+	}
+	else {
+		memset(buf, 0, info->dqi_usable_bs);
+		/* Assure block allocation... */
+		ret = write_blk(info, info->dqi_blocks, buf);
+		if (ret < 0)
+			goto out_buf;
+		blk = info->dqi_blocks++;
+	}
+	mark_info_dirty(info->dqi_sb, info->dqi_type);
+	ret = blk;
+out_buf:
+	kfree(buf);
+	return ret;
+}
+
+/* Insert empty block to the list */
+static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
+{
+	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
+	int err;
+
+	dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk);
+	dh->dqdh_prev_free = cpu_to_le32(0);
+	dh->dqdh_entries = cpu_to_le16(0);
+	err = write_blk(info, blk, buf);
+	if (err < 0)
+		return err;
+	info->dqi_free_blk = blk;
+	mark_info_dirty(info->dqi_sb, info->dqi_type);
+	return 0;
+}
+
+/* Remove given block from the list of blocks with free entries */
+static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
+			       uint blk)
+{
+	char *tmpbuf = getdqbuf(info->dqi_usable_bs);
+	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
+	uint nextblk = le32_to_cpu(dh->dqdh_next_free);
+	uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
+	int err;
+
+	if (!tmpbuf)
+		return -ENOMEM;
+	if (nextblk) {
+		err = read_blk(info, nextblk, tmpbuf);
+		if (err < 0)
+			goto out_buf;
+		((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
+							dh->dqdh_prev_free;
+		err = write_blk(info, nextblk, tmpbuf);
+		if (err < 0)
+			goto out_buf;
+	}
+	if (prevblk) {
+		err = read_blk(info, prevblk, tmpbuf);
+		if (err < 0)
+			goto out_buf;
+		((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
+							dh->dqdh_next_free;
+		err = write_blk(info, prevblk, tmpbuf);
+		if (err < 0)
+			goto out_buf;
+	} else {
+		info->dqi_free_entry = nextblk;
+		mark_info_dirty(info->dqi_sb, info->dqi_type);
+	}
+	kfree(tmpbuf);
+	dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
+	/* No matter whether write succeeds block is out of list */
+	if (write_blk(info, blk, buf) < 0)
+		quota_error(info->dqi_sb, "Can't write block (%u) "
+			    "with free entries", blk);
+	return 0;
+out_buf:
+	kfree(tmpbuf);
+	return err;
+}
+
+/* Insert given block to the beginning of list with free entries */
+static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
+			       uint blk)
+{
+	char *tmpbuf = getdqbuf(info->dqi_usable_bs);
+	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
+	int err;
+
+	if (!tmpbuf)
+		return -ENOMEM;
+	dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
+	dh->dqdh_prev_free = cpu_to_le32(0);
+	err = write_blk(info, blk, buf);
+	if (err < 0)
+		goto out_buf;
+	if (info->dqi_free_entry) {
+		err = read_blk(info, info->dqi_free_entry, tmpbuf);
+		if (err < 0)
+			goto out_buf;
+		((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
+							cpu_to_le32(blk);
+		err = write_blk(info, info->dqi_free_entry, tmpbuf);
+		if (err < 0)
+			goto out_buf;
+	}
+	kfree(tmpbuf);
+	info->dqi_free_entry = blk;
+	mark_info_dirty(info->dqi_sb, info->dqi_type);
+	return 0;
+out_buf:
+	kfree(tmpbuf);
+	return err;
+}
+
+/* Is the entry in the block free? */
+int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk)
+{
+	int i;
+
+	for (i = 0; i < info->dqi_entry_size; i++)
+		if (disk[i])
+			return 0;
+	return 1;
+}
+EXPORT_SYMBOL(qtree_entry_unused);
+
+/* Find space for dquot */
+static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
+			      struct dquot *dquot, int *err)
+{
+	uint blk, i;
+	struct qt_disk_dqdbheader *dh;
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	char *ddquot;
+
+	*err = 0;
+	if (!buf) {
+		*err = -ENOMEM;
+		return 0;
+	}
+	dh = (struct qt_disk_dqdbheader *)buf;
+	if (info->dqi_free_entry) {
+		blk = info->dqi_free_entry;
+		*err = read_blk(info, blk, buf);
+		if (*err < 0)
+			goto out_buf;
+	} else {
+		blk = get_free_dqblk(info);
+		if ((int)blk < 0) {
+			*err = blk;
+			kfree(buf);
+			return 0;
+		}
+		memset(buf, 0, info->dqi_usable_bs);
+		/* This is enough as the block is already zeroed and the entry
+		 * list is empty... */
+		info->dqi_free_entry = blk;
+		mark_info_dirty(dquot->dq_sb, dquot->dq_id.type);
+	}
+	/* Block will be full? */
+	if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) {
+		*err = remove_free_dqentry(info, buf, blk);
+		if (*err < 0) {
+			quota_error(dquot->dq_sb, "Can't remove block (%u) "
+				    "from entry free list", blk);
+			goto out_buf;
+		}
+	}
+	le16_add_cpu(&dh->dqdh_entries, 1);
+	/* Find free structure in block */
+	ddquot = buf + sizeof(struct qt_disk_dqdbheader);
+	for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
+		if (qtree_entry_unused(info, ddquot))
+			break;
+		ddquot += info->dqi_entry_size;
+	}
+#ifdef __QUOTA_QT_PARANOIA
+	if (i == qtree_dqstr_in_blk(info)) {
+		quota_error(dquot->dq_sb, "Data block full but it shouldn't");
+		*err = -EIO;
+		goto out_buf;
+	}
+#endif
+	*err = write_blk(info, blk, buf);
+	if (*err < 0) {
+		quota_error(dquot->dq_sb, "Can't write quota data block %u",
+			    blk);
+		goto out_buf;
+	}
+	dquot->dq_off = (blk << info->dqi_blocksize_bits) +
+			sizeof(struct qt_disk_dqdbheader) +
+			i * info->dqi_entry_size;
+	kfree(buf);
+	return blk;
+out_buf:
+	kfree(buf);
+	return 0;
+}
+
+/* Insert reference to structure into the trie */
+static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
+			  uint *treeblk, int depth)
+{
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	int ret = 0, newson = 0, newact = 0;
+	__le32 *ref;
+	uint newblk;
+
+	if (!buf)
+		return -ENOMEM;
+	if (!*treeblk) {
+		ret = get_free_dqblk(info);
+		if (ret < 0)
+			goto out_buf;
+		*treeblk = ret;
+		memset(buf, 0, info->dqi_usable_bs);
+		newact = 1;
+	} else {
+		ret = read_blk(info, *treeblk, buf);
+		if (ret < 0) {
+			quota_error(dquot->dq_sb, "Can't read tree quota "
+				    "block %u", *treeblk);
+			goto out_buf;
+		}
+	}
+	ref = (__le32 *)buf;
+	newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
+	if (!newblk)
+		newson = 1;
+	if (depth == info->dqi_qtree_depth - 1) {
+#ifdef __QUOTA_QT_PARANOIA
+		if (newblk) {
+			quota_error(dquot->dq_sb, "Inserting already present "
+				    "quota entry (block %u)",
+				    le32_to_cpu(ref[get_index(info,
+						dquot->dq_id, depth)]));
+			ret = -EIO;
+			goto out_buf;
+		}
+#endif
+		newblk = find_free_dqentry(info, dquot, &ret);
+	} else {
+		ret = do_insert_tree(info, dquot, &newblk, depth+1);
+	}
+	if (newson && ret >= 0) {
+		ref[get_index(info, dquot->dq_id, depth)] =
+							cpu_to_le32(newblk);
+		ret = write_blk(info, *treeblk, buf);
+	} else if (newact && ret < 0) {
+		put_free_dqblk(info, buf, *treeblk);
+	}
+out_buf:
+	kfree(buf);
+	return ret;
+}
+
+/* Wrapper for inserting quota structure into tree */
+static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
+				 struct dquot *dquot)
+{
+	int tmp = QT_TREEOFF;
+	return do_insert_tree(info, dquot, &tmp, 0);
+}
+
+/*
+ * We don't have to be afraid of deadlocks as we never have quotas on quota
+ * files...
+ */
+int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
+{
+	int type = dquot->dq_id.type;
+	struct super_block *sb = dquot->dq_sb;
+	ssize_t ret;
+	char *ddquot = getdqbuf(info->dqi_entry_size);
+
+	if (!ddquot)
+		return -ENOMEM;
+
+	/* dq_off is guarded by dqio_mutex */
+	if (!dquot->dq_off) {
+		ret = dq_insert_tree(info, dquot);
+		if (ret < 0) {
+			quota_error(sb, "Error %zd occurred while creating "
+				    "quota", ret);
+			kfree(ddquot);
+			return ret;
+		}
+	}
+	spin_lock(&dq_data_lock);
+	info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
+	spin_unlock(&dq_data_lock);
+	ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
+				    dquot->dq_off);
+	if (ret != info->dqi_entry_size) {
+		quota_error(sb, "dquota write failed");
+		if (ret >= 0)
+			ret = -ENOSPC;
+	} else {
+		ret = 0;
+	}
+	dqstats_inc(DQST_WRITES);
+	kfree(ddquot);
+
+	return ret;
+}
+EXPORT_SYMBOL(qtree_write_dquot);
+
+/* Free dquot entry in data block */
+static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
+			uint blk)
+{
+	struct qt_disk_dqdbheader *dh;
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	int ret = 0;
+
+	if (!buf)
+		return -ENOMEM;
+	if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
+		quota_error(dquot->dq_sb, "Quota structure has offset to "
+			"other block (%u) than it should (%u)", blk,
+			(uint)(dquot->dq_off >> info->dqi_blocksize_bits));
+		goto out_buf;
+	}
+	ret = read_blk(info, blk, buf);
+	if (ret < 0) {
+		quota_error(dquot->dq_sb, "Can't read quota data block %u",
+			    blk);
+		goto out_buf;
+	}
+	dh = (struct qt_disk_dqdbheader *)buf;
+	le16_add_cpu(&dh->dqdh_entries, -1);
+	if (!le16_to_cpu(dh->dqdh_entries)) {	/* Block got free? */
+		ret = remove_free_dqentry(info, buf, blk);
+		if (ret >= 0)
+			ret = put_free_dqblk(info, buf, blk);
+		if (ret < 0) {
+			quota_error(dquot->dq_sb, "Can't move quota data block "
+				    "(%u) to free list", blk);
+			goto out_buf;
+		}
+	} else {
+		memset(buf +
+		       (dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)),
+		       0, info->dqi_entry_size);
+		if (le16_to_cpu(dh->dqdh_entries) ==
+		    qtree_dqstr_in_blk(info) - 1) {
+			/* Insert will write block itself */
+			ret = insert_free_dqentry(info, buf, blk);
+			if (ret < 0) {
+				quota_error(dquot->dq_sb, "Can't insert quota "
+				    "data block (%u) to free entry list", blk);
+				goto out_buf;
+			}
+		} else {
+			ret = write_blk(info, blk, buf);
+			if (ret < 0) {
+				quota_error(dquot->dq_sb, "Can't write quota "
+					    "data block %u", blk);
+				goto out_buf;
+			}
+		}
+	}
+	dquot->dq_off = 0;	/* Quota is now unattached */
+out_buf:
+	kfree(buf);
+	return ret;
+}
+
+/* Remove reference to dquot from tree */
+static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
+		       uint *blk, int depth)
+{
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	int ret = 0;
+	uint newblk;
+	__le32 *ref = (__le32 *)buf;
+
+	if (!buf)
+		return -ENOMEM;
+	ret = read_blk(info, *blk, buf);
+	if (ret < 0) {
+		quota_error(dquot->dq_sb, "Can't read quota data block %u",
+			    *blk);
+		goto out_buf;
+	}
+	newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
+	if (depth == info->dqi_qtree_depth - 1) {
+		ret = free_dqentry(info, dquot, newblk);
+		newblk = 0;
+	} else {
+		ret = remove_tree(info, dquot, &newblk, depth+1);
+	}
+	if (ret >= 0 && !newblk) {
+		int i;
+		ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0);
+		/* Block got empty? */
+		for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++)
+			;
+		/* Don't put the root block into the free block list */
+		if (i == (info->dqi_usable_bs >> 2)
+		    && *blk != QT_TREEOFF) {
+			put_free_dqblk(info, buf, *blk);
+			*blk = 0;
+		} else {
+			ret = write_blk(info, *blk, buf);
+			if (ret < 0)
+				quota_error(dquot->dq_sb,
+					    "Can't write quota tree block %u",
+					    *blk);
+		}
+	}
+out_buf:
+	kfree(buf);
+	return ret;
+}
+
+/* Delete dquot from tree */
+int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
+{
+	uint tmp = QT_TREEOFF;
+
+	if (!dquot->dq_off)	/* Even not allocated? */
+		return 0;
+	return remove_tree(info, dquot, &tmp, 0);
+}
+EXPORT_SYMBOL(qtree_delete_dquot);
+
+/* Find entry in block */
+static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
+				 struct dquot *dquot, uint blk)
+{
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	loff_t ret = 0;
+	int i;
+	char *ddquot;
+
+	if (!buf)
+		return -ENOMEM;
+	ret = read_blk(info, blk, buf);
+	if (ret < 0) {
+		quota_error(dquot->dq_sb, "Can't read quota tree "
+			    "block %u", blk);
+		goto out_buf;
+	}
+	ddquot = buf + sizeof(struct qt_disk_dqdbheader);
+	for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
+		if (info->dqi_ops->is_id(ddquot, dquot))
+			break;
+		ddquot += info->dqi_entry_size;
+	}
+	if (i == qtree_dqstr_in_blk(info)) {
+		quota_error(dquot->dq_sb,
+			    "Quota for id %u referenced but not present",
+			    from_kqid(&init_user_ns, dquot->dq_id));
+		ret = -EIO;
+		goto out_buf;
+	} else {
+		ret = (blk << info->dqi_blocksize_bits) + sizeof(struct
+		  qt_disk_dqdbheader) + i * info->dqi_entry_size;
+	}
+out_buf:
+	kfree(buf);
+	return ret;
+}
+
+/* Find entry for given id in the tree */
+static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
+				struct dquot *dquot, uint blk, int depth)
+{
+	char *buf = getdqbuf(info->dqi_usable_bs);
+	loff_t ret = 0;
+	__le32 *ref = (__le32 *)buf;
+
+	if (!buf)
+		return -ENOMEM;
+	ret = read_blk(info, blk, buf);
+	if (ret < 0) {
+		quota_error(dquot->dq_sb, "Can't read quota tree block %u",
+			    blk);
+		goto out_buf;
+	}
+	ret = 0;
+	blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
+	if (!blk)	/* No reference? */
+		goto out_buf;
+	if (depth < info->dqi_qtree_depth - 1)
+		ret = find_tree_dqentry(info, dquot, blk, depth+1);
+	else
+		ret = find_block_dqentry(info, dquot, blk);
+out_buf:
+	kfree(buf);
+	return ret;
+}
+
+/* Find entry for given id in the tree - wrapper function */
+static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info,
+				  struct dquot *dquot)
+{
+	return find_tree_dqentry(info, dquot, QT_TREEOFF, 0);
+}
+
+int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
+{
+	int type = dquot->dq_id.type;
+	struct super_block *sb = dquot->dq_sb;
+	loff_t offset;
+	char *ddquot;
+	int ret = 0;
+
+#ifdef __QUOTA_QT_PARANOIA
+	/* Invalidated quota? */
+	if (!sb_dqopt(dquot->dq_sb)->files[type]) {
+		quota_error(sb, "Quota invalidated while reading!");
+		return -EIO;
+	}
+#endif
+	/* Do we know offset of the dquot entry in the quota file? */
+	if (!dquot->dq_off) {
+		offset = find_dqentry(info, dquot);
+		if (offset <= 0) {	/* Entry not present? */
+			if (offset < 0)
+				quota_error(sb,"Can't read quota structure "
+					    "for id %u",
+					    from_kqid(&init_user_ns,
+						      dquot->dq_id));
+			dquot->dq_off = 0;
+			set_bit(DQ_FAKE_B, &dquot->dq_flags);
+			memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
+			ret = offset;
+			goto out;
+		}
+		dquot->dq_off = offset;
+	}
+	ddquot = getdqbuf(info->dqi_entry_size);
+	if (!ddquot)
+		return -ENOMEM;
+	ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
+				   dquot->dq_off);
+	if (ret != info->dqi_entry_size) {
+		if (ret >= 0)
+			ret = -EIO;
+		quota_error(sb, "Error while reading quota structure for id %u",
+			    from_kqid(&init_user_ns, dquot->dq_id));
+		set_bit(DQ_FAKE_B, &dquot->dq_flags);
+		memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
+		kfree(ddquot);
+		goto out;
+	}
+	spin_lock(&dq_data_lock);
+	info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
+	if (!dquot->dq_dqb.dqb_bhardlimit &&
+	    !dquot->dq_dqb.dqb_bsoftlimit &&
+	    !dquot->dq_dqb.dqb_ihardlimit &&
+	    !dquot->dq_dqb.dqb_isoftlimit)
+		set_bit(DQ_FAKE_B, &dquot->dq_flags);
+	spin_unlock(&dq_data_lock);
+	kfree(ddquot);
+out:
+	dqstats_inc(DQST_READS);
+	return ret;
+}
+EXPORT_SYMBOL(qtree_read_dquot);
+
+/* Check whether dquot should not be deleted. We know we are
+ * the only one operating on dquot (thanks to dq_lock) */
+int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
+{
+	if (test_bit(DQ_FAKE_B, &dquot->dq_flags) &&
+	    !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
+		return qtree_delete_dquot(info, dquot);
+	return 0;
+}
+EXPORT_SYMBOL(qtree_release_dquot);

fs/quota/quota_tree.h

@@ -0,0 +1,25 @@
+/*
+ *	Definitions of structures for vfsv0 quota format
+ */
+
+#ifndef _LINUX_QUOTA_TREE_H
+#define _LINUX_QUOTA_TREE_H
+
+#include <linux/types.h>
+#include <linux/quota.h>
+
+/*
+ *  Structure of header of block with quota structures. It is padded to 16 bytes so
+ *  there will be space for exactly 21 quota-entries in a block
+ */
+struct qt_disk_dqdbheader {
+	__le32 dqdh_next_free;	/* Number of next block with free entry */
+	__le32 dqdh_prev_free;	/* Number of previous block with free entry */
+	__le16 dqdh_entries;	/* Number of valid entries in block */
+	__le16 dqdh_pad1;
+	__le32 dqdh_pad2;
+};
+
+#define QT_TREEOFF	1		/* Offset of tree in file in blocks */
+
+#endif /* _LINUX_QUOTAIO_TREE_H */

fs/quota/quota_v1.c

@@ -0,0 +1,235 @@
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/quota.h>
+#include <linux/quotaops.h>
+#include <linux/dqblk_v1.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+#include <asm/byteorder.h>
+
+#include "quotaio_v1.h"
+
+MODULE_AUTHOR("Jan Kara");
+MODULE_DESCRIPTION("Old quota format support");
+MODULE_LICENSE("GPL");
+
+#define QUOTABLOCK_BITS 10
+#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
+
+static inline qsize_t v1_stoqb(qsize_t space)
+{
+	return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
+}
+
+static inline qsize_t v1_qbtos(qsize_t blocks)
+{
+	return blocks << QUOTABLOCK_BITS;
+}
+
+static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
+{
+	m->dqb_ihardlimit = d->dqb_ihardlimit;
+	m->dqb_isoftlimit = d->dqb_isoftlimit;
+	m->dqb_curinodes = d->dqb_curinodes;
+	m->dqb_bhardlimit = v1_qbtos(d->dqb_bhardlimit);
+	m->dqb_bsoftlimit = v1_qbtos(d->dqb_bsoftlimit);
+	m->dqb_curspace = v1_qbtos(d->dqb_curblocks);
+	m->dqb_itime = d->dqb_itime;
+	m->dqb_btime = d->dqb_btime;
+}
+
+static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
+{
+	d->dqb_ihardlimit = m->dqb_ihardlimit;
+	d->dqb_isoftlimit = m->dqb_isoftlimit;
+	d->dqb_curinodes = m->dqb_curinodes;
+	d->dqb_bhardlimit = v1_stoqb(m->dqb_bhardlimit);
+	d->dqb_bsoftlimit = v1_stoqb(m->dqb_bsoftlimit);
+	d->dqb_curblocks = v1_stoqb(m->dqb_curspace);
+	d->dqb_itime = m->dqb_itime;
+	d->dqb_btime = m->dqb_btime;
+}
+
+static int v1_read_dqblk(struct dquot *dquot)
+{
+	int type = dquot->dq_id.type;
+	struct v1_disk_dqblk dqblk;
+
+	if (!sb_dqopt(dquot->dq_sb)->files[type])
+		return -EINVAL;
+
+	/* Set structure to 0s in case read fails/is after end of file */
+	memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
+	dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
+			sizeof(struct v1_disk_dqblk),
+			v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
+
+	v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
+	if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
+	    dquot->dq_dqb.dqb_bsoftlimit == 0 &&
+	    dquot->dq_dqb.dqb_ihardlimit == 0 &&
+	    dquot->dq_dqb.dqb_isoftlimit == 0)
+		set_bit(DQ_FAKE_B, &dquot->dq_flags);
+	dqstats_inc(DQST_READS);
+
+	return 0;
+}
+
+static int v1_commit_dqblk(struct dquot *dquot)
+{
+	short type = dquot->dq_id.type;
+	ssize_t ret;
+	struct v1_disk_dqblk dqblk;
+
+	v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
+	if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
+	    ((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
+		dqblk.dqb_btime =
+			sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
+		dqblk.dqb_itime =
+			sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
+	}
+	ret = 0;
+	if (sb_dqopt(dquot->dq_sb)->files[type])
+		ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
+			(char *)&dqblk, sizeof(struct v1_disk_dqblk),
+			v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
+	if (ret != sizeof(struct v1_disk_dqblk)) {
+		quota_error(dquot->dq_sb, "dquota write failed");
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
+	ret = 0;
+
+out:
+	dqstats_inc(DQST_WRITES);
+
+	return ret;
+}
+
+/* Magics of new quota format */
+#define V2_INITQMAGICS {\
+	0xd9c01f11,     /* USRQUOTA */\
+	0xd9c01927      /* GRPQUOTA */\
+}
+
+/* Header of new quota format */
+struct v2_disk_dqheader {
+	__le32 dqh_magic;        /* Magic number identifying file */
+	__le32 dqh_version;      /* File version */
+};
+
+static int v1_check_quota_file(struct super_block *sb, int type)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	ulong blocks;
+	size_t off; 
+	struct v2_disk_dqheader dqhead;
+	ssize_t size;
+	loff_t isize;
+	static const uint quota_magics[] = V2_INITQMAGICS;
+
+	isize = i_size_read(inode);
+	if (!isize)
+		return 0;
+	blocks = isize >> BLOCK_SIZE_BITS;
+	off = isize & (BLOCK_SIZE - 1);
+	if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
+	    sizeof(struct v1_disk_dqblk))
+		return 0;
+	/* Doublecheck whether we didn't get file with new format - with old
+	 * quotactl() this could happen */
+	size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
+				    sizeof(struct v2_disk_dqheader), 0);
+	if (size != sizeof(struct v2_disk_dqheader))
+		return 1;	/* Probably not new format */
+	if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
+		return 1;	/* Definitely not new format */
+	printk(KERN_INFO
+	       "VFS: %s: Refusing to turn on old quota format on given file."
+	       " It probably contains newer quota format.\n", sb->s_id);
+        return 0;		/* Seems like a new format file -> refuse it */
+}
+
+static int v1_read_file_info(struct super_block *sb, int type)
+{
+	struct quota_info *dqopt = sb_dqopt(sb);
+	struct v1_disk_dqblk dqblk;
+	int ret;
+
+	ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
+				sizeof(struct v1_disk_dqblk), v1_dqoff(0));
+	if (ret != sizeof(struct v1_disk_dqblk)) {
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
+	ret = 0;
+	/* limits are stored as unsigned 32-bit data */
+	dqopt->info[type].dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
+	dqopt->info[type].dqi_max_ino_limit = 0xffffffff;
+	dqopt->info[type].dqi_igrace =
+			dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
+	dqopt->info[type].dqi_bgrace =
+			dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
+out:
+	return ret;
+}
+
+static int v1_write_file_info(struct super_block *sb, int type)
+{
+	struct quota_info *dqopt = sb_dqopt(sb);
+	struct v1_disk_dqblk dqblk;
+	int ret;
+
+	dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
+	ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
+				sizeof(struct v1_disk_dqblk), v1_dqoff(0));
+	if (ret != sizeof(struct v1_disk_dqblk)) {
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
+	dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
+	dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
+	ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
+	      sizeof(struct v1_disk_dqblk), v1_dqoff(0));
+	if (ret == sizeof(struct v1_disk_dqblk))
+		ret = 0;
+	else if (ret > 0)
+		ret = -EIO;
+out:
+	return ret;
+}
+
+static const struct quota_format_ops v1_format_ops = {
+	.check_quota_file	= v1_check_quota_file,
+	.read_file_info		= v1_read_file_info,
+	.write_file_info	= v1_write_file_info,
+	.free_file_info		= NULL,
+	.read_dqblk		= v1_read_dqblk,
+	.commit_dqblk		= v1_commit_dqblk,
+};
+
+static struct quota_format_type v1_quota_format = {
+	.qf_fmt_id	= QFMT_VFS_OLD,
+	.qf_ops		= &v1_format_ops,
+	.qf_owner	= THIS_MODULE
+};
+
+static int __init init_v1_quota_format(void)
+{
+        return register_quota_format(&v1_quota_format);
+}
+
+static void __exit exit_v1_quota_format(void)
+{
+        unregister_quota_format(&v1_quota_format);
+}
+
+module_init(init_v1_quota_format);
+module_exit(exit_v1_quota_format);
+

fs/quota/quota_v2.c

@@ -0,0 +1,340 @@
+/*
+ *	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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/quotaops.h>
+
+#include <asm/byteorder.h>
+
+#include "quota_tree.h"
+#include "quotaio_v2.h"
+
+MODULE_AUTHOR("Jan Kara");
+MODULE_DESCRIPTION("Quota format v2 support");
+MODULE_LICENSE("GPL");
+
+#define __QUOTA_V2_PARANOIA
+
+static void v2r0_mem2diskdqb(void *dp, struct dquot *dquot);
+static void v2r0_disk2memdqb(struct dquot *dquot, void *dp);
+static int v2r0_is_id(void *dp, struct dquot *dquot);
+static void v2r1_mem2diskdqb(void *dp, struct dquot *dquot);
+static void v2r1_disk2memdqb(struct dquot *dquot, void *dp);
+static int v2r1_is_id(void *dp, struct dquot *dquot);
+
+static struct qtree_fmt_operations v2r0_qtree_ops = {
+	.mem2disk_dqblk = v2r0_mem2diskdqb,
+	.disk2mem_dqblk = v2r0_disk2memdqb,
+	.is_id = v2r0_is_id,
+};
+
+static struct qtree_fmt_operations v2r1_qtree_ops = {
+	.mem2disk_dqblk = v2r1_mem2diskdqb,
+	.disk2mem_dqblk = v2r1_disk2memdqb,
+	.is_id = v2r1_is_id,
+};
+
+#define QUOTABLOCK_BITS 10
+#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
+
+static inline qsize_t v2_stoqb(qsize_t space)
+{
+	return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
+}
+
+static inline qsize_t v2_qbtos(qsize_t blocks)
+{
+	return blocks << QUOTABLOCK_BITS;
+}
+
+static int v2_read_header(struct super_block *sb, int type,
+			  struct v2_disk_dqheader *dqhead)
+{
+	ssize_t size;
+
+	size = sb->s_op->quota_read(sb, type, (char *)dqhead,
+				    sizeof(struct v2_disk_dqheader), 0);
+	if (size != sizeof(struct v2_disk_dqheader)) {
+		quota_error(sb, "Failed header read: expected=%zd got=%zd",
+			    sizeof(struct v2_disk_dqheader), size);
+		return 0;
+	}
+	return 1;
+}
+
+/* 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;
+	static const uint quota_magics[] = V2_INITQMAGICS;
+	static const uint quota_versions[] = V2_INITQVERSIONS;
+ 
+	if (!v2_read_header(sb, type, &dqhead))
+		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)
+{
+	struct v2_disk_dqinfo dinfo;
+	struct v2_disk_dqheader dqhead;
+	struct mem_dqinfo *info = sb_dqinfo(sb, type);
+	struct qtree_mem_dqinfo *qinfo;
+	ssize_t size;
+	unsigned int version;
+
+	if (!v2_read_header(sb, type, &dqhead))
+		return -1;
+	version = le32_to_cpu(dqhead.dqh_version);
+	if ((info->dqi_fmt_id == QFMT_VFS_V0 && version != 0) ||
+	    (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1))
+		return -1;
+
+	size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
+	       sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
+	if (size != sizeof(struct v2_disk_dqinfo)) {
+		quota_error(sb, "Can't read info structure");
+		return -1;
+	}
+	info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_NOFS);
+	if (!info->dqi_priv) {
+		printk(KERN_WARNING
+		       "Not enough memory for quota information structure.\n");
+		return -ENOMEM;
+	}
+	qinfo = info->dqi_priv;
+	if (version == 0) {
+		/* limits are stored as unsigned 32-bit data */
+		info->dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
+		info->dqi_max_ino_limit = 0xffffffff;
+	} else {
+		/* used space is stored as unsigned 64-bit value in bytes */
+		info->dqi_max_spc_limit = 0xffffffffffffffffULL; /* 2^64-1 */
+		info->dqi_max_ino_limit = 0xffffffffffffffffULL;
+	}
+	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);
+	qinfo->dqi_sb = sb;
+	qinfo->dqi_type = type;
+	qinfo->dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
+	qinfo->dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
+	qinfo->dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
+	qinfo->dqi_blocksize_bits = V2_DQBLKSIZE_BITS;
+	qinfo->dqi_usable_bs = 1 << V2_DQBLKSIZE_BITS;
+	qinfo->dqi_qtree_depth = qtree_depth(qinfo);
+	if (version == 0) {
+		qinfo->dqi_entry_size = sizeof(struct v2r0_disk_dqblk);
+		qinfo->dqi_ops = &v2r0_qtree_ops;
+	} else {
+		qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
+		qinfo->dqi_ops = &v2r1_qtree_ops;
+	}
+	return 0;
+}
+
+/* Write information header to quota file */
+static int v2_write_file_info(struct super_block *sb, int type)
+{
+	struct v2_disk_dqinfo dinfo;
+	struct mem_dqinfo *info = sb_dqinfo(sb, type);
+	struct qtree_mem_dqinfo *qinfo = info->dqi_priv;
+	ssize_t size;
+
+	spin_lock(&dq_data_lock);
+	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);
+	spin_unlock(&dq_data_lock);
+	dinfo.dqi_blocks = cpu_to_le32(qinfo->dqi_blocks);
+	dinfo.dqi_free_blk = cpu_to_le32(qinfo->dqi_free_blk);
+	dinfo.dqi_free_entry = cpu_to_le32(qinfo->dqi_free_entry);
+	size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
+	       sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
+	if (size != sizeof(struct v2_disk_dqinfo)) {
+		quota_error(sb, "Can't write info structure");
+		return -1;
+	}
+	return 0;
+}
+
+static void v2r0_disk2memdqb(struct dquot *dquot, void *dp)
+{
+	struct v2r0_disk_dqblk *d = dp, empty;
+	struct mem_dqblk *m = &dquot->dq_dqb;
+
+	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 = v2_qbtos(le32_to_cpu(d->dqb_bhardlimit));
+	m->dqb_bsoftlimit = v2_qbtos(le32_to_cpu(d->dqb_bsoftlimit));
+	m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
+	m->dqb_btime = le64_to_cpu(d->dqb_btime);
+	/* We need to escape back all-zero structure */
+	memset(&empty, 0, sizeof(struct v2r0_disk_dqblk));
+	empty.dqb_itime = cpu_to_le64(1);
+	if (!memcmp(&empty, dp, sizeof(struct v2r0_disk_dqblk)))
+		m->dqb_itime = 0;
+}
+
+static void v2r0_mem2diskdqb(void *dp, struct dquot *dquot)
+{
+	struct v2r0_disk_dqblk *d = dp;
+	struct mem_dqblk *m = &dquot->dq_dqb;
+	struct qtree_mem_dqinfo *info =
+			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
+
+	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(v2_stoqb(m->dqb_bhardlimit));
+	d->dqb_bsoftlimit = cpu_to_le32(v2_stoqb(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(from_kqid(&init_user_ns, dquot->dq_id));
+	if (qtree_entry_unused(info, dp))
+		d->dqb_itime = cpu_to_le64(1);
+}
+
+static int v2r0_is_id(void *dp, struct dquot *dquot)
+{
+	struct v2r0_disk_dqblk *d = dp;
+	struct qtree_mem_dqinfo *info =
+			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
+
+	if (qtree_entry_unused(info, dp))
+		return 0;
+	return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
+				le32_to_cpu(d->dqb_id)),
+		      dquot->dq_id);
+}
+
+static void v2r1_disk2memdqb(struct dquot *dquot, void *dp)
+{
+	struct v2r1_disk_dqblk *d = dp, empty;
+	struct mem_dqblk *m = &dquot->dq_dqb;
+
+	m->dqb_ihardlimit = le64_to_cpu(d->dqb_ihardlimit);
+	m->dqb_isoftlimit = le64_to_cpu(d->dqb_isoftlimit);
+	m->dqb_curinodes = le64_to_cpu(d->dqb_curinodes);
+	m->dqb_itime = le64_to_cpu(d->dqb_itime);
+	m->dqb_bhardlimit = v2_qbtos(le64_to_cpu(d->dqb_bhardlimit));
+	m->dqb_bsoftlimit = v2_qbtos(le64_to_cpu(d->dqb_bsoftlimit));
+	m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
+	m->dqb_btime = le64_to_cpu(d->dqb_btime);
+	/* We need to escape back all-zero structure */
+	memset(&empty, 0, sizeof(struct v2r1_disk_dqblk));
+	empty.dqb_itime = cpu_to_le64(1);
+	if (!memcmp(&empty, dp, sizeof(struct v2r1_disk_dqblk)))
+		m->dqb_itime = 0;
+}
+
+static void v2r1_mem2diskdqb(void *dp, struct dquot *dquot)
+{
+	struct v2r1_disk_dqblk *d = dp;
+	struct mem_dqblk *m = &dquot->dq_dqb;
+	struct qtree_mem_dqinfo *info =
+			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
+
+	d->dqb_ihardlimit = cpu_to_le64(m->dqb_ihardlimit);
+	d->dqb_isoftlimit = cpu_to_le64(m->dqb_isoftlimit);
+	d->dqb_curinodes = cpu_to_le64(m->dqb_curinodes);
+	d->dqb_itime = cpu_to_le64(m->dqb_itime);
+	d->dqb_bhardlimit = cpu_to_le64(v2_stoqb(m->dqb_bhardlimit));
+	d->dqb_bsoftlimit = cpu_to_le64(v2_stoqb(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(from_kqid(&init_user_ns, dquot->dq_id));
+	if (qtree_entry_unused(info, dp))
+		d->dqb_itime = cpu_to_le64(1);
+}
+
+static int v2r1_is_id(void *dp, struct dquot *dquot)
+{
+	struct v2r1_disk_dqblk *d = dp;
+	struct qtree_mem_dqinfo *info =
+			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
+
+	if (qtree_entry_unused(info, dp))
+		return 0;
+	return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
+				le32_to_cpu(d->dqb_id)),
+		      dquot->dq_id);
+}
+
+static int v2_read_dquot(struct dquot *dquot)
+{
+	return qtree_read_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+}
+
+static int v2_write_dquot(struct dquot *dquot)
+{
+	return qtree_write_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+}
+
+static int v2_release_dquot(struct dquot *dquot)
+{
+	return qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+}
+
+static int v2_free_file_info(struct super_block *sb, int type)
+{
+	kfree(sb_dqinfo(sb, type)->dqi_priv);
+	return 0;
+}
+
+static const 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		= v2_free_file_info,
+	.read_dqblk		= v2_read_dquot,
+	.commit_dqblk		= v2_write_dquot,
+	.release_dqblk		= v2_release_dquot,
+};
+
+static struct quota_format_type v2r0_quota_format = {
+	.qf_fmt_id	= QFMT_VFS_V0,
+	.qf_ops		= &v2_format_ops,
+	.qf_owner	= THIS_MODULE
+};
+
+static struct quota_format_type v2r1_quota_format = {
+	.qf_fmt_id	= QFMT_VFS_V1,
+	.qf_ops		= &v2_format_ops,
+	.qf_owner	= THIS_MODULE
+};
+
+static int __init init_v2_quota_format(void)
+{
+	int ret;
+
+	ret = register_quota_format(&v2r0_quota_format);
+	if (ret)
+		return ret;
+	return register_quota_format(&v2r1_quota_format);
+}
+
+static void __exit exit_v2_quota_format(void)
+{
+	unregister_quota_format(&v2r0_quota_format);
+	unregister_quota_format(&v2r1_quota_format);
+}
+
+module_init(init_v2_quota_format);
+module_exit(exit_v2_quota_format);

fs/quota/quotaio_v1.h

@@ -0,0 +1,33 @@
+#ifndef _LINUX_QUOTAIO_V1_H
+#define _LINUX_QUOTAIO_V1_H
+
+#include <linux/types.h>
+
+/*
+ * The following constants define the amount of time given a user
+ * before the soft limits are treated as hard limits (usually resulting
+ * in an allocation failure). The timer is started when the user crosses
+ * their soft limit, it is reset when they go below their soft limit.
+ */
+#define MAX_IQ_TIME  604800	/* (7*24*60*60) 1 week */
+#define MAX_DQ_TIME  604800	/* (7*24*60*60) 1 week */
+
+/*
+ * The following structure defines the format of the disk quota file
+ * (as it appears on disk) - the file is an array of these structures
+ * indexed by user or group number.
+ */
+struct v1_disk_dqblk {
+	__u32 dqb_bhardlimit;	/* absolute limit on disk blks alloc */
+	__u32 dqb_bsoftlimit;	/* preferred limit on disk blks */
+	__u32 dqb_curblocks;	/* current block count */
+	__u32 dqb_ihardlimit;	/* absolute limit on allocated inodes */
+	__u32 dqb_isoftlimit;	/* preferred inode limit */
+	__u32 dqb_curinodes;	/* current # allocated inodes */
+	time_t dqb_btime;	/* time limit for excessive disk use */
+	time_t dqb_itime;	/* time limit for excessive inode use */
+};
+
+#define v1_dqoff(UID)      ((loff_t)((UID) * sizeof (struct v1_disk_dqblk)))
+
+#endif	/* _LINUX_QUOTAIO_V1_H */

fs/quota/quotaio_v2.h

@@ -0,0 +1,73 @@
+/*
+ *	Definitions of structures for vfsv0 quota format
+ */
+
+#ifndef _LINUX_QUOTAIO_V2_H
+#define _LINUX_QUOTAIO_V2_H
+
+#include <linux/types.h>
+#include <linux/quota.h>
+
+/*
+ * Definitions of magics and versions of current quota files
+ */
+#define V2_INITQMAGICS {\
+	0xd9c01f11,	/* USRQUOTA */\
+	0xd9c01927	/* GRPQUOTA */\
+}
+
+#define V2_INITQVERSIONS {\
+	1,		/* USRQUOTA */\
+	1		/* GRPQUOTA */\
+}
+
+/* First generic header */
+struct v2_disk_dqheader {
+	__le32 dqh_magic;	/* Magic number identifying file */
+	__le32 dqh_version;	/* File version */
+};
+
+/*
+ * The following structure defines the format of the disk quota file
+ * (as it appears on disk) - the file is a radix tree whose leaves point
+ * to blocks of these structures.
+ */
+struct v2r0_disk_dqblk {
+	__le32 dqb_id;		/* id this quota applies to */
+	__le32 dqb_ihardlimit;	/* absolute limit on allocated inodes */
+	__le32 dqb_isoftlimit;	/* preferred inode limit */
+	__le32 dqb_curinodes;	/* current # allocated inodes */
+	__le32 dqb_bhardlimit;	/* absolute limit on disk space (in QUOTABLOCK_SIZE) */
+	__le32 dqb_bsoftlimit;	/* preferred limit on disk space (in QUOTABLOCK_SIZE) */
+	__le64 dqb_curspace;	/* current space occupied (in bytes) */
+	__le64 dqb_btime;	/* time limit for excessive disk use */
+	__le64 dqb_itime;	/* time limit for excessive inode use */
+};
+
+struct v2r1_disk_dqblk {
+	__le32 dqb_id;		/* id this quota applies to */
+	__le32 dqb_pad;
+	__le64 dqb_ihardlimit;	/* absolute limit on allocated inodes */
+	__le64 dqb_isoftlimit;	/* preferred inode limit */
+	__le64 dqb_curinodes;	/* current # allocated inodes */
+	__le64 dqb_bhardlimit;	/* absolute limit on disk space (in QUOTABLOCK_SIZE) */
+	__le64 dqb_bsoftlimit;	/* preferred limit on disk space (in QUOTABLOCK_SIZE) */
+	__le64 dqb_curspace;	/* current space occupied (in bytes) */
+	__le64 dqb_btime;	/* time limit for excessive disk use */
+	__le64 dqb_itime;	/* time limit for excessive inode use */
+};
+
+/* Header with type and version specific information */
+struct v2_disk_dqinfo {
+	__le32 dqi_bgrace;	/* Time before block soft limit becomes hard limit */
+	__le32 dqi_igrace;	/* Time before inode soft limit becomes hard limit */
+	__le32 dqi_flags;	/* Flags for quotafile (DQF_*) */
+	__le32 dqi_blocks;	/* Number of blocks in file */
+	__le32 dqi_free_blk;	/* Number of first free block in the list */
+	__le32 dqi_free_entry;	/* Number of block with at least one free entry */
+};
+
+#define V2_DQINFOOFF	sizeof(struct v2_disk_dqheader)	/* Offset of info header in file */
+#define V2_DQBLKSIZE_BITS 10				/* Size of leaf block in tree */
+
+#endif /* _LINUX_QUOTAIO_V2_H */