Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6: (27 commits)
  ext2: Zero our b_size in ext2_quota_read()
  trivial: fix typos/grammar errors in fs/Kconfig
  quota: Coding style fixes
  quota: Remove superfluous inlines
  quota: Remove uppercase aliases for quota functions.
  nfsd: Use lowercase names of quota functions
  jfs: Use lowercase names of quota functions
  udf: Use lowercase names of quota functions
  ufs: Use lowercase names of quota functions
  reiserfs: Use lowercase names of quota functions
  ext4: Use lowercase names of quota functions
  ext3: Use lowercase names of quota functions
  ext2: Use lowercase names of quota functions
  ramfs: Remove quota call
  vfs: Use lowercase names of quota functions
  quota: Remove dqbuf_t and other cleanups
  quota: Remove NODQUOT macro
  quota: Make global quota locks cacheline aligned
  quota: Move quota files into separate directory
  ext4: quota reservation for delayed allocation
  ...

10 files changed, 4448 insertions, 0 deletions

diff --git a/fs/quota/Kconfig b/fs/quota/Kconfig
new file mode 100644
index 00000000000..8047e01ef46
--- /dev/null
+++ b/fs/quota/Kconfig
@@ -0,0 +1,59 @@
+#
+#  Quota configuration
+#
+
+config QUOTA
+	bool "Quota support"
+	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, and reiserfs file system. ext3 also supports journalled
+	  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 QUOTA && 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.
+
+# 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 v2 support"
+	depends on QUOTA
+	select QUOTA_TREE
+	help
+	  This quota format allows using quotas with 32-bit UIDs/GIDs. If you
+	  need this functionality say Y here.
+
+config QUOTACTL
+	bool
+	depends on XFS_QUOTA || QUOTA
+	default y
diff --git a/fs/quota/Makefile b/fs/quota/Makefile
new file mode 100644
index 00000000000..385a0831cc9
--- /dev/null
+++ b/fs/quota/Makefile
@@ -0,0 +1,14 @@
+#
+# Makefile for the Linux filesystems.
+#
+# 14 Sep 2000, Christoph Hellwig <hch@infradead.org>
+# Rewritten to use lists instead of if-statements.
+#
+
+obj-y :=
+
+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
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
new file mode 100644
index 00000000000..eb938015bd9
--- /dev/null
+++ b/fs/quota/dquot.c
@@ -0,0 +1,2611 @@
+/*
+ * Implementation of the diskquota system for the LINUX operating system. QUOTA
+ * is implemented using the BSD system call interface as the means of
+ * communication with the user level. This file contains the generic routines
+ * called by the different filesystems on allocation of an inode or block.
+ * These routines take care of the administration needed to have a consistent
+ * diskquota tracking system. The ideas of both user and group quotas are based
+ * on the Melbourne quota system as used on BSD derived systems. The internal
+ * implementation is based on one of the several variants of the LINUX
+ * inode-subsystem with added complexity of the diskquota system.
+ * 
+ * Author:	Marco van Wieringen <mvw@planets.elm.net>
+ *
+ * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
+ *
+ *		Revised list management to avoid races
+ *		-- Bill Hawes, <whawes@star.net>, 9/98
+ *
+ *		Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
+ *		As the consequence the locking was moved from dquot_decr_...(),
+ *		dquot_incr_...() to calling functions.
+ *		invalidate_dquots() now writes modified dquots.
+ *		Serialized quota_off() and quota_on() for mount point.
+ *		Fixed a few bugs in grow_dquots().
+ *		Fixed deadlock in write_dquot() - we no longer account quotas on
+ *		quota files
+ *		remove_dquot_ref() moved to inode.c - it now traverses through inodes
+ *		add_dquot_ref() restarts after blocking
+ *		Added check for bogus uid and fixed check for group in quotactl.
+ *		Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
+ *
+ *		Used struct list_head instead of own list struct
+ *		Invalidation of referenced dquots is no longer possible
+ *		Improved free_dquots list management
+ *		Quota and i_blocks are now updated in one place to avoid races
+ *		Warnings are now delayed so we won't block in critical section
+ *		Write updated not to require dquot lock
+ *		Jan Kara, <jack@suse.cz>, 9/2000
+ *
+ *		Added dynamic quota structure allocation
+ *		Jan Kara <jack@suse.cz> 12/2000
+ *
+ *		Rewritten quota interface. Implemented new quota format and
+ *		formats registering.
+ *		Jan Kara, <jack@suse.cz>, 2001,2002
+ *
+ *		New SMP locking.
+ *		Jan Kara, <jack@suse.cz>, 10/2002
+ *
+ *		Added journalled quota support, fix lock inversion problems
+ *		Jan Kara, <jack@suse.cz>, 2003,2004
+ *
+ * (C) Copyright 1994 - 1997 Marco van Wieringen 
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/mm.h>
+#include <linux/time.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/tty.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/security.h>
+#include <linux/kmod.h>
+#include <linux/namei.h>
+#include <linux/buffer_head.h>
+#include <linux/capability.h>
+#include <linux/quotaops.h>
+#include <linux/writeback.h> /* for inode_lock, oddly enough.. */
+#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#endif
+
+#include <asm/uaccess.h>
+
+#define __DQUOT_PARANOIA
+
+/*
+ * There are three quota SMP locks. dq_list_lock protects all lists with quotas
+ * and quota formats, dqstats structure containing statistics about the lists
+ * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
+ * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
+ * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
+ * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
+ * modifications of quota state (on quotaon and quotaoff) and readers who care
+ * about latest values take it as well.
+ *
+ * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
+ *   dq_list_lock > dq_state_lock
+ *
+ * Note that some things (eg. sb pointer, type, id) doesn't change during
+ * the life of the dquot structure and so needn't to be protected by a lock
+ *
+ * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
+ * operation is just reading pointers from inode (or not using them at all) the
+ * read lock is enough. If pointers are altered function must hold write lock
+ * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
+ * for altering the flag i_mutex is also needed).
+ *
+ * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
+ * from inodes (dquot_alloc_space() and such don't check the dq_lock).
+ * Currently dquot is locked only when it is being read to memory (or space for
+ * it is being allocated) on the first dqget() and when it is being released on
+ * the last dqput(). The allocation and release oparations are serialized by
+ * the dq_lock and by checking the use count in dquot_release().  Write
+ * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
+ * spinlock to internal buffers before writing.
+ *
+ * Lock ordering (including related VFS locks) is the following:
+ *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
+ *   dqio_mutex
+ * The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
+ * dqptr_sem. But filesystem has to count with the fact that functions such as
+ * dquot_alloc_space() acquire dqptr_sem and they usually have to be called
+ * from inside a transaction to keep filesystem consistency after a crash. Also
+ * filesystems usually want to do some IO on dquot from ->mark_dirty which is
+ * called with dqptr_sem held.
+ * i_mutex on quota files is special (it's below dqio_mutex)
+ */
+
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
+EXPORT_SYMBOL(dq_data_lock);
+
+static char *quotatypes[] = INITQFNAMES;
+static struct quota_format_type *quota_formats;	/* List of registered formats */
+static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
+
+/* SLAB cache for dquot structures */
+static struct kmem_cache *dquot_cachep;
+
+int register_quota_format(struct quota_format_type *fmt)
+{
+	spin_lock(&dq_list_lock);
+	fmt->qf_next = quota_formats;
+	quota_formats = fmt;
+	spin_unlock(&dq_list_lock);
+	return 0;
+}
+EXPORT_SYMBOL(register_quota_format);
+
+void unregister_quota_format(struct quota_format_type *fmt)
+{
+	struct quota_format_type **actqf;
+
+	spin_lock(&dq_list_lock);
+	for (actqf = &quota_formats; *actqf && *actqf != fmt;
+	     actqf = &(*actqf)->qf_next)
+		;
+	if (*actqf)
+		*actqf = (*actqf)->qf_next;
+	spin_unlock(&dq_list_lock);
+}
+EXPORT_SYMBOL(unregister_quota_format);
+
+static struct quota_format_type *find_quota_format(int id)
+{
+	struct quota_format_type *actqf;
+
+	spin_lock(&dq_list_lock);
+	for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
+	     actqf = actqf->qf_next)
+		;
+	if (!actqf || !try_module_get(actqf->qf_owner)) {
+		int qm;
+
+		spin_unlock(&dq_list_lock);
+		
+		for (qm = 0; module_names[qm].qm_fmt_id &&
+			     module_names[qm].qm_fmt_id != id; qm++)
+			;
+		if (!module_names[qm].qm_fmt_id ||
+		    request_module(module_names[qm].qm_mod_name))
+			return NULL;
+
+		spin_lock(&dq_list_lock);
+		for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
+		     actqf = actqf->qf_next)
+			;
+		if (actqf && !try_module_get(actqf->qf_owner))
+			actqf = NULL;
+	}
+	spin_unlock(&dq_list_lock);
+	return actqf;
+}
+
+static void put_quota_format(struct quota_format_type *fmt)
+{
+	module_put(fmt->qf_owner);
+}
+
+/*
+ * Dquot List Management:
+ * The quota code uses three lists for dquot management: the inuse_list,
+ * free_dquots, and dquot_hash[] array. A single dquot structure may be
+ * on all three lists, depending on its current state.
+ *
+ * All dquots are placed to the end of inuse_list when first created, and this
+ * list is used for invalidate operation, which must look at every dquot.
+ *
+ * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
+ * and this list is searched whenever we need an available dquot.  Dquots are
+ * removed from the list as soon as they are used again, and
+ * dqstats.free_dquots gives the number of dquots on the list. When
+ * dquot is invalidated it's completely released from memory.
+ *
+ * Dquots with a specific identity (device, type and id) are placed on
+ * one of the dquot_hash[] hash chains. The provides an efficient search
+ * mechanism to locate a specific dquot.
+ */
+
+static LIST_HEAD(inuse_list);
+static LIST_HEAD(free_dquots);
+static unsigned int dq_hash_bits, dq_hash_mask;
+static struct hlist_head *dquot_hash;
+
+struct dqstats dqstats;
+EXPORT_SYMBOL(dqstats);
+
+static inline unsigned int
+hashfn(const struct super_block *sb, unsigned int id, int type)
+{
+	unsigned long tmp;
+
+	tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
+	return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
+}
+
+/*
+ * Following list functions expect dq_list_lock to be held
+ */
+static inline void insert_dquot_hash(struct dquot *dquot)
+{
+	struct hlist_head *head;
+	head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
+	hlist_add_head(&dquot->dq_hash, head);
+}
+
+static inline void remove_dquot_hash(struct dquot *dquot)
+{
+	hlist_del_init(&dquot->dq_hash);
+}
+
+static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
+				unsigned int id, int type)
+{
+	struct hlist_node *node;
+	struct dquot *dquot;
+
+	hlist_for_each (node, dquot_hash+hashent) {
+		dquot = hlist_entry(node, struct dquot, dq_hash);
+		if (dquot->dq_sb == sb && dquot->dq_id == id &&
+		    dquot->dq_type == type)
+			return dquot;
+	}
+	return NULL;
+}
+
+/* Add a dquot to the tail of the free list */
+static inline void put_dquot_last(struct dquot *dquot)
+{
+	list_add_tail(&dquot->dq_free, &free_dquots);
+	dqstats.free_dquots++;
+}
+
+static inline void remove_free_dquot(struct dquot *dquot)
+{
+	if (list_empty(&dquot->dq_free))
+		return;
+	list_del_init(&dquot->dq_free);
+	dqstats.free_dquots--;
+}
+
+static inline void put_inuse(struct dquot *dquot)
+{
+	/* We add to the back of inuse list so we don't have to restart
+	 * when traversing this list and we block */
+	list_add_tail(&dquot->dq_inuse, &inuse_list);
+	dqstats.allocated_dquots++;
+}
+
+static inline void remove_inuse(struct dquot *dquot)
+{
+	dqstats.allocated_dquots--;
+	list_del(&dquot->dq_inuse);
+}
+/*
+ * End of list functions needing dq_list_lock
+ */
+
+static void wait_on_dquot(struct dquot *dquot)
+{
+	mutex_lock(&dquot->dq_lock);
+	mutex_unlock(&dquot->dq_lock);
+}
+
+static inline int dquot_dirty(struct dquot *dquot)
+{
+	return test_bit(DQ_MOD_B, &dquot->dq_flags);
+}
+
+static inline int mark_dquot_dirty(struct dquot *dquot)
+{
+	return dquot->dq_sb->dq_op->mark_dirty(dquot);
+}
+
+int dquot_mark_dquot_dirty(struct dquot *dquot)
+{
+	spin_lock(&dq_list_lock);
+	if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
+		list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
+				info[dquot->dq_type].dqi_dirty_list);
+	spin_unlock(&dq_list_lock);
+	return 0;
+}
+EXPORT_SYMBOL(dquot_mark_dquot_dirty);
+
+/* This function needs dq_list_lock */
+static inline int clear_dquot_dirty(struct dquot *dquot)
+{
+	if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
+		return 0;
+	list_del_init(&dquot->dq_dirty);
+	return 1;
+}
+
+void mark_info_dirty(struct super_block *sb, int type)
+{
+	set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
+}
+EXPORT_SYMBOL(mark_info_dirty);
+
+/*
+ *	Read dquot from disk and alloc space for it
+ */
+
+int dquot_acquire(struct dquot *dquot)
+{
+	int ret = 0, ret2 = 0;
+	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+
+	mutex_lock(&dquot->dq_lock);
+	mutex_lock(&dqopt->dqio_mutex);
+	if (!test_bit(DQ_READ_B, &dquot->dq_flags))
+		ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
+	if (ret < 0)
+		goto out_iolock;
+	set_bit(DQ_READ_B, &dquot->dq_flags);
+	/* Instantiate dquot if needed */
+	if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
+		ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
+		/* Write the info if needed */
+		if (info_dirty(&dqopt->info[dquot->dq_type])) {
+			ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
+						dquot->dq_sb, dquot->dq_type);
+		}
+		if (ret < 0)
+			goto out_iolock;
+		if (ret2 < 0) {
+			ret = ret2;
+			goto out_iolock;
+		}
+	}
+	set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
+out_iolock:
+	mutex_unlock(&dqopt->dqio_mutex);
+	mutex_unlock(&dquot->dq_lock);
+	return ret;
+}
+EXPORT_SYMBOL(dquot_acquire);
+
+/*
+ *	Write dquot to disk
+ */
+int dquot_commit(struct dquot *dquot)
+{
+	int ret = 0, ret2 = 0;
+	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+
+	mutex_lock(&dqopt->dqio_mutex);
+	spin_lock(&dq_list_lock);
+	if (!clear_dquot_dirty(dquot)) {
+		spin_unlock(&dq_list_lock);
+		goto out_sem;
+	}
+	spin_unlock(&dq_list_lock);
+	/* Inactive dquot can be only if there was error during read/init
+	 * => we have better not writing it */
+	if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
+		ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
+		if (info_dirty(&dqopt->info[dquot->dq_type])) {
+			ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
+						dquot->dq_sb, dquot->dq_type);
+		}
+		if (ret >= 0)
+			ret = ret2;
+	}
+out_sem:
+	mutex_unlock(&dqopt->dqio_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(dquot_commit);
+
+/*
+ *	Release dquot
+ */
+int dquot_release(struct dquot *dquot)
+{
+	int ret = 0, ret2 = 0;
+	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+
+	mutex_lock(&dquot->dq_lock);
+	/* Check whether we are not racing with some other dqget() */
+	if (atomic_read(&dquot->dq_count) > 1)
+		goto out_dqlock;
+	mutex_lock(&dqopt->dqio_mutex);
+	if (dqopt->ops[dquot->dq_type]->release_dqblk) {
+		ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
+		/* Write the info */
+		if (info_dirty(&dqopt->info[dquot->dq_type])) {
+			ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
+						dquot->dq_sb, dquot->dq_type);
+		}
+		if (ret >= 0)
+			ret = ret2;
+	}
+	clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
+	mutex_unlock(&dqopt->dqio_mutex);
+out_dqlock:
+	mutex_unlock(&dquot->dq_lock);
+	return ret;
+}
+EXPORT_SYMBOL(dquot_release);
+
+void dquot_destroy(struct dquot *dquot)
+{
+	kmem_cache_free(dquot_cachep, dquot);
+}
+EXPORT_SYMBOL(dquot_destroy);
+
+static inline void do_destroy_dquot(struct dquot *dquot)
+{
+	dquot->dq_sb->dq_op->destroy_dquot(dquot);
+}
+
+/* Invalidate all dquots on the list. Note that this function is called after
+ * quota is disabled and pointers from inodes removed so there cannot be new
+ * quota users. There can still be some users of quotas due to inodes being
+ * just deleted or pruned by prune_icache() (those are not attached to any
+ * list) or parallel quotactl call. We have to wait for such users.
+ */
+static void invalidate_dquots(struct super_block *sb, int type)
+{
+	struct dquot *dquot, *tmp;
+
+restart:
+	spin_lock(&dq_list_lock);
+	list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
+		if (dquot->dq_sb != sb)
+			continue;
+		if (dquot->dq_type != type)
+			continue;
+		/* Wait for dquot users */
+		if (atomic_read(&dquot->dq_count)) {
+			DEFINE_WAIT(wait);
+
+			atomic_inc(&dquot->dq_count);
+			prepare_to_wait(&dquot->dq_wait_unused, &wait,
+					TASK_UNINTERRUPTIBLE);
+			spin_unlock(&dq_list_lock);
+			/* Once dqput() wakes us up, we know it's time to free
+			 * the dquot.
+			 * IMPORTANT: we rely on the fact that there is always
+			 * at most one process waiting for dquot to free.
+			 * Otherwise dq_count would be > 1 and we would never
+			 * wake up.
+			 */
+			if (atomic_read(&dquot->dq_count) > 1)
+				schedule();
+			finish_wait(&dquot->dq_wait_unused, &wait);
+			dqput(dquot);
+			/* At this moment dquot() need not exist (it could be
+			 * reclaimed by prune_dqcache(). Hence we must
+			 * restart. */
+			goto restart;
+		}
+		/*
+		 * Quota now has no users and it has been written on last
+		 * dqput()
+		 */
+		remove_dquot_hash(dquot);
+		remove_free_dquot(dquot);
+		remove_inuse(dquot);
+		do_destroy_dquot(dquot);
+	}
+	spin_unlock(&dq_list_lock);
+}
+
+/* Call callback for every active dquot on given filesystem */
+int dquot_scan_active(struct super_block *sb,
+		      int (*fn)(struct dquot *dquot, unsigned long priv),
+		      unsigned long priv)
+{
+	struct dquot *dquot, *old_dquot = NULL;
+	int ret = 0;
+
+	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
+	spin_lock(&dq_list_lock);
+	list_for_each_entry(dquot, &inuse_list, dq_inuse) {
+		if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
+			continue;
+		if (dquot->dq_sb != sb)
+			continue;
+		/* Now we have active dquot so we can just increase use count */
+		atomic_inc(&dquot->dq_count);
+		dqstats.lookups++;
+		spin_unlock(&dq_list_lock);
+		dqput(old_dquot);
+		old_dquot = dquot;
+		ret = fn(dquot, priv);
+		if (ret < 0)
+			goto out;
+		spin_lock(&dq_list_lock);
+		/* We are safe to continue now because our dquot could not
+		 * be moved out of the inuse list while we hold the reference */
+	}
+	spin_unlock(&dq_list_lock);
+out:
+	dqput(old_dquot);
+	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(dquot_scan_active);
+
+int vfs_quota_sync(struct super_block *sb, int type)
+{
+	struct list_head *dirty;
+	struct dquot *dquot;
+	struct quota_info *dqopt = sb_dqopt(sb);
+	int cnt;
+
+	mutex_lock(&dqopt->dqonoff_mutex);
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+		if (type != -1 && cnt != type)
+			continue;
+		if (!sb_has_quota_active(sb, cnt))
+			continue;
+		spin_lock(&dq_list_lock);
+		dirty = &dqopt->info[cnt].dqi_dirty_list;
+		while (!list_empty(dirty)) {
+			dquot = list_first_entry(dirty, struct dquot,
+						 dq_dirty);
+			/* Dirty and inactive can be only bad dquot... */
+			if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
+				clear_dquot_dirty(dquot);
+				continue;
+			}
+			/* Now we have active dquot from which someone is
+ 			 * holding reference so we can safely just increase
+			 * use count */
+			atomic_inc(&dquot->dq_count);
+			dqstats.lookups++;
+			spin_unlock(&dq_list_lock);
+			sb->dq_op->write_dquot(dquot);
+			dqput(dquot);
+			spin_lock(&dq_list_lock);
+		}
+		spin_unlock(&dq_list_lock);
+	}
+
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
+		if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
+		    && info_dirty(&dqopt->info[cnt]))
+			sb->dq_op->write_info(sb, cnt);
+	spin_lock(&dq_list_lock);
+	dqstats.syncs++;
+	spin_unlock(&dq_list_lock);
+	mutex_unlock(&dqopt->dqonoff_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL(vfs_quota_sync);
+
+/* Free unused dquots from cache */
+static void prune_dqcache(int count)
+{
+	struct list_head *head;
+	struct dquot *dquot;
+
+	head = free_dquots.prev;
+	while (head != &free_dquots && count) {
+		dquot = list_entry(head, struct dquot, dq_free);
+		remove_dquot_hash(dquot);
+		remove_free_dquot(dquot);
+		remove_inuse(dquot);
+		do_destroy_dquot(dquot);
+		count--;
+		head = free_dquots.prev;
+	}
+}
+
+/*
+ * This is called from kswapd when we think we need some
+ * more memory
+ */
+
+static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
+{
+	if (nr) {
+		spin_lock(&dq_list_lock);
+		prune_dqcache(nr);
+		spin_unlock(&dq_list_lock);
+	}
+	return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
+}
+
+static struct shrinker dqcache_shrinker = {
+	.shrink = shrink_dqcache_memory,
+	.seeks = DEFAULT_SEEKS,
+};
+
+/*
+ * Put reference to dquot
+ * NOTE: If you change this function please check whether dqput_blocks() works right...
+ */
+void dqput(struct dquot *dquot)
+{
+	int ret;
+
+	if (!dquot)
+		return;
+#ifdef __DQUOT_PARANOIA
+	if (!atomic_read(&dquot->dq_count)) {
+		printk("VFS: dqput: trying to free free dquot\n");
+		printk("VFS: device %s, dquot of %s %d\n",
+			dquot->dq_sb->s_id,
+			quotatypes[dquot->dq_type],
+			dquot->dq_id);
+		BUG();
+	}
+#endif
+	
+	spin_lock(&dq_list_lock);
+	dqstats.drops++;
+	spin_unlock(&dq_list_lock);
+we_slept:
+	spin_lock(&dq_list_lock);
+	if (atomic_read(&dquot->dq_count) > 1) {
+		/* We have more than one user... nothing to do */
+		atomic_dec(&dquot->dq_count);
+		/* Releasing dquot during quotaoff phase? */
+		if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_type) &&
+		    atomic_read(&dquot->dq_count) == 1)
+			wake_up(&dquot->dq_wait_unused);
+		spin_unlock(&dq_list_lock);
+		return;
+	}
+	/* Need to release dquot? */
+	if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
+		spin_unlock(&dq_list_lock);
+		/* Commit dquot before releasing */
+		ret = dquot->dq_sb->dq_op->write_dquot(dquot);
+		if (ret < 0) {
+			printk(KERN_ERR "VFS: cannot write quota structure on "
+				"device %s (error %d). Quota may get out of "
+				"sync!\n", dquot->dq_sb->s_id, ret);
+			/*
+			 * We clear dirty bit anyway, so that we avoid
+			 * infinite loop here
+			 */
+			spin_lock(&dq_list_lock);
+			clear_dquot_dirty(dquot);
+			spin_unlock(&dq_list_lock);
+		}
+		goto we_slept;
+	}
+	/* Clear flag in case dquot was inactive (something bad happened) */
+	clear_dquot_dirty(dquot);
+	if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
+		spin_unlock(&dq_list_lock);
+		dquot->dq_sb->dq_op->release_dquot(dquot);
+		goto we_slept;
+	}
+	atomic_dec(&dquot->dq_count);
+#ifdef __DQUOT_PARANOIA
+	/* sanity check */
+	BUG_ON(!list_empty(&dquot->dq_free));
+#endif
+	put_dquot_last(dquot);
+	spin_unlock(&dq_list_lock);
+}
+EXPORT_SYMBOL(dqput);
+
+struct dquot *dquot_alloc(struct super_block *sb, int type)
+{
+	return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
+}
+EXPORT_SYMBOL(dquot_alloc);
+
+static struct dquot *get_empty_dquot(struct super_block *sb, int type)
+{
+	struct dquot *dquot;
+
+	dquot = sb->dq_op->alloc_dquot(sb, type);
+	if(!dquot)
+		return NULL;
+
+	mutex_init(&dquot->dq_lock);
+	INIT_LIST_HEAD(&dquot->dq_free);
+	INIT_LIST_HEAD(&dquot->dq_inuse);
+	INIT_HLIST_NODE(&dquot->dq_hash);
+	INIT_LIST_HEAD(&dquot->dq_dirty);
+	init_waitqueue_head(&dquot->dq_wait_unused);
+	dquot->dq_sb = sb;
+	dquot->dq_type = type;
+	atomic_set(&dquot->dq_count, 1);
+
+	return dquot;
+}
+
+/*
+ * Get reference to dquot
+ *
+ * Locking is slightly tricky here. We are guarded from parallel quotaoff()
+ * destroying our dquot by:
+ *   a) checking for quota flags under dq_list_lock and
+ *   b) getting a reference to dquot before we release dq_list_lock
+ */
+struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
+{
+	unsigned int hashent = hashfn(sb, id, type);
+	struct dquot *dquot = NULL, *empty = NULL;
+
+        if (!sb_has_quota_active(sb, type))
+		return NULL;
+we_slept:
+	spin_lock(&dq_list_lock);
+	spin_lock(&dq_state_lock);
+	if (!sb_has_quota_active(sb, type)) {
+		spin_unlock(&dq_state_lock);
+		spin_unlock(&dq_list_lock);
+		goto out;
+	}
+	spin_unlock(&dq_state_lock);
+
+	dquot = find_dquot(hashent, sb, id, type);
+	if (!dquot) {
+		if (!empty) {
+			spin_unlock(&dq_list_lock);
+			empty = get_empty_dquot(sb, type);
+			if (!empty)
+				schedule();	/* Try to wait for a moment... */
+			goto we_slept;
+		}
+		dquot = empty;
+		empty = NULL;
+		dquot->dq_id = id;
+		/* all dquots go on the inuse_list */
+		put_inuse(dquot);
+		/* hash it first so it can be found */
+		insert_dquot_hash(dquot);
+		dqstats.lookups++;
+		spin_unlock(&dq_list_lock);
+	} else {
+		if (!atomic_read(&dquot->dq_count))
+			remove_free_dquot(dquot);
+		atomic_inc(&dquot->dq_count);
+		dqstats.cache_hits++;
+		dqstats.lookups++;
+		spin_unlock(&dq_list_lock);
+	}
+	/* Wait for dq_lock - after this we know that either dquot_release() is
+	 * already finished or it will be canceled due to dq_count > 1 test */
+	wait_on_dquot(dquot);
+	/* Read the dquot / allocate space in quota file */
+	if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) &&
+	    sb->dq_op->acquire_dquot(dquot) < 0) {
+		dqput(dquot);
+		dquot = NULL;
+		goto out;
+	}
+#ifdef __DQUOT_PARANOIA
+	BUG_ON(!dquot->dq_sb);	/* Has somebody invalidated entry under us? */
+#endif
+out:
+	if (empty)
+		do_destroy_dquot(empty);
+
+	return dquot;
+}
+EXPORT_SYMBOL(dqget);
+
+static int dqinit_needed(struct inode *inode, int type)
+{
+	int cnt;
+
+	if (IS_NOQUOTA(inode))
+		return 0;
+	if (type != -1)
+		return !inode->i_dquot[type];
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
+		if (!inode->i_dquot[cnt])
+			return 1;
+	return 0;
+}
+
+/* This routine is guarded by dqonoff_mutex mutex */
+static void add_dquot_ref(struct super_block *sb, int type)
+{
+	struct inode *inode, *old_inode = NULL;
+
+	spin_lock(&inode_lock);
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+		if (!atomic_read(&inode->i_writecount))
+			continue;
+		if (!dqinit_needed(inode, type))
+			continue;
+		if (inode->i_state & (I_FREEING|I_WILL_FREE))
+			continue;
+
+		__iget(inode);
+		spin_unlock(&inode_lock);
+
+		iput(old_inode);
+		sb->dq_op->initialize(inode, type);
+		/* We hold a reference to 'inode' so it couldn't have been
+		 * removed from s_inodes list while we dropped the inode_lock.
+		 * We cannot iput the inode now as we can be holding the last
+		 * reference and we cannot iput it under inode_lock. So we
+		 * keep the reference and iput it later. */
+		old_inode = inode;
+		spin_lock(&inode_lock);
+	}
+	spin_unlock(&inode_lock);
+	iput(old_inode);
+}
+
+/*
+ * Return 0 if dqput() won't block.
+ * (note that 1 doesn't necessarily mean blocking)
+ */
+static inline int dqput_blocks(struct dquot *dquot)
+{
+	if (atomic_read(&dquot->dq_count) <= 1)
+		return 1;
+	return 0;
+}
+
+/*
+ * Remove references to dquots from inode and add dquot to list for freeing
+ * if we have the last referece to dquot
+ * We can't race with anybody because we hold dqptr_sem for writing...
+ */
+static int remove_inode_dquot_ref(struct inode *inode, int type,
+				  struct list_head *tofree_head)
+{
+	struct dquot *dquot = inode->i_dquot[type];
+
+	inode->i_dquot[type] = NULL;
+	if (dquot) {
+		if (dqput_blocks(dquot)) {
+#ifdef __DQUOT_PARANOIA
+			if (atomic_read(&dquot->dq_count) != 1)
+				printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
+#endif
+			spin_lock(&dq_list_lock);
+			/* As dquot must have currently users it can't be on
+			 * the free list... */
+			list_add(&dquot->dq_free, tofree_head);
+			spin_unlock(&dq_list_lock);
+			return 1;
+		}
+		else
+			dqput(dquot);   /* We have guaranteed we won't block */
+	}
+	return 0;
+}
+
+/*
+ * Free list of dquots
+ * Dquots are removed from inodes and no new references can be got so we are
+ * the only ones holding reference
+ */
+static void put_dquot_list(struct list_head *tofree_head)
+{
+	struct list_head *act_head;
+	struct dquot *dquot;
+
+	act_head = tofree_head->next;
+	while (act_head != tofree_head) {
+		dquot = list_entry(act_head, struct dquot, dq_free);
+		act_head = act_head->next;
+		/* Remove dquot from the list so we won't have problems... */
+		list_del_init(&dquot->dq_free);
+		dqput(dquot);
+	}
+}
+
+static void remove_dquot_ref(struct super_block *sb, int type,
+		struct list_head *tofree_head)
+{
+	struct inode *inode;
+
+	spin_lock(&inode_lock);
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+		if (!IS_NOQUOTA(inode))
+			remove_inode_dquot_ref(inode, type, tofree_head);
+	}