[PATCH 11/11] ubifs: Add quota support

[Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>]

From: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx>

This introduces poor man's quota support for UBIFS. Unlike other
implementations we never store anything on the flash. This has two
big advantages:

- No possible regressions with a changed on-disk format
- no quota files can get out of sync.

There are downsides aswell:

- During mount the whole index must be scanned which takes some time
- The quota limits must be set manually each time a filesystem is mounted.

UBIFS is targetted for embedded systems and quota limits are likely not
changed interactively, so having to restore the quota limits with a
script shouldn't be a big deal. The mount time penalty is a price we
must pay, but for that we get a simple and straight forward
implementation for this rather rarely used feature.

The quota data itself is stored in a red-black tree in memory. It is
implemented as a quota format. When enabled with the "quota" mount
option all three quota types (user, group, project) are enabled.

The quota integration into UBIFS is taken from a series posted earlier
by Dongsheng Yang. Like the earlier series we only account regular files
for quota. All others are counted in the number of files, but do not
require any quota space.

iSigned-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
 fs/ubifs/Makefile  |   1 +
 fs/ubifs/dir.c     |  18 +-
 fs/ubifs/file.c    |  43 ++++
 fs/ubifs/ioctl.c   |  32 +++
 fs/ubifs/journal.c |   2 +
 fs/ubifs/quota.c   | 590 +++++++++++++++++++++++++++++++++++++++++++++
 fs/ubifs/super.c   |  45 +++-
 fs/ubifs/tnc.c     |   2 +-
 fs/ubifs/ubifs.h   |  27 +++
 9 files changed, 756 insertions(+), 4 deletions(-)
 create mode 100644 fs/ubifs/quota.c

diff --git a/fs/ubifs/Makefile b/fs/ubifs/Makefile
index 5c4b845754a7..07f657f5ea8f 100644
--- a/fs/ubifs/Makefile
+++ b/fs/ubifs/Makefile
@@ -9,3 +9,4 @@ ubifs-y += misc.o
 ubifs-$(CONFIG_FS_ENCRYPTION) += crypto.o
 ubifs-$(CONFIG_UBIFS_FS_XATTR) += xattr.o
 ubifs-$(CONFIG_UBIFS_FS_AUTHENTICATION) += auth.o
+ubifs-$(CONFIG_QUOTA) += quota.o
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index e2d3dfb67ae3..b7a2c255ffcd 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -113,6 +113,11 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
 			 current_time(inode);
 	inode->i_mapping->nrpages = 0;
 
+	dquot_initialize(inode);
+	err = dquot_alloc_inode(inode);
+	if (err)
+		goto fail_drop;
+
 	if (ubifs_inode(dir)->flags & UBIFS_PROJINHERIT_FL)
 		ui->projid = ubifs_inode(dir)->projid;
 	else
@@ -158,8 +163,8 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
 			spin_unlock(&c->cnt_lock);
 			ubifs_err(c, "out of inode numbers");
 			make_bad_inode(inode);
-			iput(inode);
-			return ERR_PTR(-EINVAL);
+			err = -EINVAL;
+			goto fail_free;
 		}
 		ubifs_warn(c, "running out of inode numbers (current %lu, max %u)",
 			   (unsigned long)c->highest_inum, INUM_WATERMARK);
@@ -187,6 +192,13 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
 	}
 
 	return inode;
+
+fail_free:
+	dquot_free_inode(inode);
+fail_drop:
+	dquot_drop(inode);
+	iput(inode);
+	return ERR_PTR(err);
 }
 
 static int dbg_check_name(const struct ubifs_info *c,
@@ -776,6 +788,8 @@ static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
 	unsigned int saved_nlink = inode->i_nlink;
 	struct fscrypt_name nm;
 
+	dquot_initialize(inode);
+
 	/*
 	 * Budget request settings: deletion direntry, deletion inode (+1 for
 	 * @dirtied_ino), changing the parent directory inode. If budgeting
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 400970d740bb..a2800d56217f 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -427,8 +427,10 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 	struct ubifs_inode *ui = ubifs_inode(inode);
 	pgoff_t index = pos >> PAGE_SHIFT;
 	int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
+	int quota_size = 0;
 	int skipped_read = 0;
 	struct page *page;
+	int ret = 0;
 
 	ubifs_assert(c, ubifs_inode(inode)->ui_size == inode->i_size);
 	ubifs_assert(c, !c->ro_media && !c->ro_mount);
@@ -436,6 +438,16 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 	if (unlikely(c->ro_error))
 		return -EROFS;
 
+	quota_size = ((pos + len) - inode->i_size);
+	if (quota_size < 0)
+		quota_size = 0;
+	if (S_ISREG(inode->i_mode)) {
+		dquot_initialize(inode);
+		ret = dquot_alloc_space_nodirty(inode, quota_size);
+		if (unlikely(ret))
+			return ret;
+	}
+
 	/* Try out the fast-path part first */
 	page = grab_cache_page_write_begin(mapping, index, flags);
 	if (unlikely(!page))
@@ -541,6 +553,7 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,
 	struct ubifs_inode *ui = ubifs_inode(inode);
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
 	loff_t end_pos = pos + len;
+	int quota_size = 0;
 	int appending = !!(end_pos > inode->i_size);
 
 	dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
@@ -559,6 +572,11 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,
 		dbg_gen("copied %d instead of %d, read page and repeat",
 			copied, len);
 		cancel_budget(c, page, ui, appending);
+		quota_size = ((pos + len) - inode->i_size);
+		if (quota_size < 0)
+			quota_size = 0;
+		if (S_ISREG(inode->i_mode))
+			dquot_free_space_nodirty(inode, quota_size);
 		ClearPageChecked(page);
 
 		/*
@@ -1112,6 +1130,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
 	int err;
 	struct ubifs_budget_req req;
 	loff_t old_size = inode->i_size, new_size = attr->ia_size;
+	loff_t quota_size = (old_size - new_size);
 	int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1;
 	struct ubifs_inode *ui = ubifs_inode(inode);
 
@@ -1191,6 +1210,10 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
 	do_attr_changes(inode, attr);
 	err = ubifs_jnl_truncate(c, inode, old_size, new_size);
 	mutex_unlock(&ui->ui_mutex);
+	if (quota_size < 0)
+		quota_size = 0;
+	if (S_ISREG(inode->i_mode))
+		dquot_free_space_nodirty(inode, quota_size);
 
 out_budg:
 	if (budgeted)
@@ -1227,6 +1250,17 @@ static int do_setattr(struct ubifs_info *c, struct inode *inode,
 
 	if (attr->ia_valid & ATTR_SIZE) {
 		dbg_gen("size %lld -> %lld", inode->i_size, new_size);
+		if (S_ISREG(inode->i_mode)) {
+			if (new_size > inode->i_size) {
+				err = dquot_alloc_space_nodirty(inode, new_size - inode->i_size);
+				if (err) {
+					ubifs_release_budget(c, &req);
+					return err;
+				}
+			} else {
+				dquot_free_space_nodirty(inode, inode->i_size - new_size);
+			}
+		}
 		truncate_setsize(inode, new_size);
 	}
 
@@ -1278,6 +1312,15 @@ int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
 	if (err)
 		return err;
 
+	if (is_quota_modification(inode, attr))
+		dquot_initialize(inode);
+	if ((attr->ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
+	    (attr->ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
+		err = dquot_transfer(inode, attr);
+		if (err)
+			return err;
+	}
+
 	if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size < inode->i_size)
 		/* Truncation to a smaller size */
 		err = do_truncation(c, inode, attr);
diff --git a/fs/ubifs/ioctl.c b/fs/ubifs/ioctl.c
index 824def711381..0805665ce0b4 100644
--- a/fs/ubifs/ioctl.c
+++ b/fs/ubifs/ioctl.c
@@ -157,16 +157,48 @@ static int ubifs_ioctl_check_project(struct ubifs_inode *ui, struct fsxattr *fa)
 	return 0;
 }
 
+#ifdef CONFIG_QUOTA
+static int ubifs_transfer_project_quota(struct inode *inode, kprojid_t kprojid)
+{
+	struct dquot *transfer_to[MAXQUOTAS] = {};
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	struct super_block *sb = c->vfs_sb;
+	int err = 0;
+
+	err = dquot_initialize(inode);
+	if (err)
+		return err;
+
+	transfer_to[PRJQUOTA] = dqget(sb, make_kqid_projid(kprojid));
+	if (!IS_ERR(transfer_to[PRJQUOTA])) {
+		err = __dquot_transfer(inode, transfer_to);
+		dqput(transfer_to[PRJQUOTA]);
+	}
+
+	return err;
+}
+#else
+static int ubifs_transfer_project_quota(struct inode *inode, kprojid_t kprojid)
+{
+	return 0;
+}
+#endif
+
 static int ubifs_ioc_setproject(struct file *file, __u32 projid)
 {
 	struct inode *inode = file_inode(file);
 	struct ubifs_inode *ui = ubifs_inode(inode);
 	kprojid_t kprojid;
+	int err;
 
 	kprojid = make_kprojid(&init_user_ns, (projid_t)projid);
 	if (projid_eq(kprojid, ui->projid))
 		return 0;
 
+	err = ubifs_transfer_project_quota(inode, kprojid);
+	if (err)
+		return err;
+
 	ui->projid = kprojid;
 
 	return 0;
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index d8961993f9dd..cba061c74c41 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -630,6 +630,8 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
 			goto out_finish;
 		}
 		ui->del_cmtno = c->cmt_no;
+		if (S_ISREG(inode->i_mode))
+			dquot_free_space_nodirty((struct inode *)inode, inode->i_size);
 	}
 
 	err = write_head(c, BASEHD, dent, len, &lnum, &dent_offs, sync);
diff --git a/fs/ubifs/quota.c b/fs/ubifs/quota.c
new file mode 100644
index 000000000000..88351c227975
--- /dev/null
+++ b/fs/ubifs/quota.c
@@ -0,0 +1,590 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2019 Pengutronix, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
+ */
+#include "ubifs.h"
+
+struct ubifs_dqblk {
+	struct mem_dqblk dqblk;
+	struct rb_node rb;
+	struct kqid kqid;
+};
+
+/**
+ * ubifs_dqblk_insert - find qid in tree
+ * @c: UBIFS file-system description object
+ * @new: The new entry to insert
+ *
+ * This inserts a new entry to the dqblk tree which is sorted by qids. Caller
+ * must make sure this entry doesn't exist already.
+ */
+static void ubifs_dqblk_insert(struct ubifs_info *c, struct ubifs_dqblk *new)
+{
+	struct rb_root *root = &c->dqblk_tree[new->kqid.type];
+	struct rb_node **link = &root->rb_node, *parent = NULL;
+	struct ubifs_dqblk *ud;
+
+	/* Go to the bottom of the tree */
+	while (*link) {
+		parent = *link;
+
+		ud = rb_entry(parent, struct ubifs_dqblk, rb);
+
+		if (qid_lt(new->kqid, ud->kqid))
+			link = &(*link)->rb_left;
+		else
+			link = &(*link)->rb_right;
+	}
+
+	/* Put the new node there */
+	rb_link_node(&new->rb, parent, link);
+	rb_insert_color(&new->rb, root);
+}
+
+/**
+ * ubifs_dqblk_find - find qid in tree
+ * @c: UBIFS file-system description object
+ * @qid: The qid to look for
+ *
+ * This walks the dqblk tree and searches a given qid. Returns the dqblk entry
+ * when found or NULL otherwise.
+ */
+static struct ubifs_dqblk *ubifs_dqblk_find(struct ubifs_info *c,
+					    struct kqid qid)
+{
+	struct rb_node *node = c->dqblk_tree[qid.type].rb_node;
+
+	while (node) {
+		struct ubifs_dqblk *ud = rb_entry(node, struct ubifs_dqblk, rb);
+
+		if (qid_eq(qid, ud->kqid))
+			return ud;
+
+		if (qid_lt(qid, ud->kqid))
+			node = node->rb_left;
+		else
+			node = node->rb_right;
+	}
+
+	return NULL;
+}
+
+/**
+ * ubifs_dqblk_find_next - find the next qid
+ * @c: UBIFS file-system description object
+ * @qid: The qid to look for
+ *
+ * Find the next dqblk entry with a qid that is bigger or equally big than the
+ * given qid. Returns the next dqblk entry if found or NULL if no dqblk exists
+ * with a qid that is at least equally big.
+ */
+static struct ubifs_dqblk *ubifs_dqblk_find_next(struct ubifs_info *c,
+						 struct kqid qid)
+{
+	struct rb_node *node = c->dqblk_tree[qid.type].rb_node;
+	struct ubifs_dqblk *next = NULL;
+
+	while (node) {
+		struct ubifs_dqblk *ud = rb_entry(node, struct ubifs_dqblk, rb);
+
+		if (qid_eq(qid, ud->kqid))
+			return ud;
+
+		if (qid_lt(qid, ud->kqid)) {
+			if (!next || qid_lt(ud->kqid, next->kqid))
+				next = ud;
+
+			node = node->rb_left;
+		} else {
+			node = node->rb_right;
+		}
+	}
+
+	return next;
+}
+
+/**
+ * ubifs_dqblk_get - get dqblk entry for given qid
+ * @c: UBIFS file-system description object
+ * @qid: The qid to look for
+ *
+ * This searches the given qid in the dqblk tree and returns it if found. If not,
+ * a new dqblk entry is created, inserted into the dqblk tree and returned.
+ */
+static struct ubifs_dqblk *ubifs_dqblk_get(struct ubifs_info *c,
+					   struct kqid qid)
+{
+	struct ubifs_dqblk *ud;
+
+	ud = ubifs_dqblk_find(c, qid);
+	if (ud)
+		return ud;
+
+	ud = kzalloc(sizeof(*ud), GFP_KERNEL);
+	if (!ud)
+		return NULL;
+
+	ud->kqid = qid;
+
+	ubifs_dqblk_insert(c, ud);
+
+	return ud;
+}
+
+/**
+ * ubifs_check_quota_file - check if quota file is valid for this format
+ * @sb: The superblock
+ * @type: Quota type
+ *
+ * We currently do not store any quota file on flash. It's completely in RAM and
+ * thus always valid.
+ */
+static int ubifs_check_quota_file(struct super_block *sb, int type)
+{
+	return 1;
+}
+
+/**
+ * ubifs_read_file_info - read quota file info
+ * @sb: The superblock
+ * @type: Quota type
+ *
+ * We currently do not store any quota info on flash. Just fill in default
+ * values.
+ */
+static int ubifs_read_file_info(struct super_block *sb, int type)
+{
+	struct quota_info *dqopt = sb_dqopt(sb);
+	struct mem_dqinfo *info = &dqopt->info[type];
+
+	down_read(&dqopt->dqio_sem);
+
+	/*
+	 * Used space is stored as unsigned 64-bit value in bytes but
+	 * quota core supports only signed 64-bit values so use that
+	 * as a limit
+	 */
+	info->dqi_max_spc_limit = 0x7fffffffffffffffLL; /* 2^63-1 */
+	info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
+	info->dqi_bgrace = 0;
+	info->dqi_igrace = 0;
+	info->dqi_flags = 0;
+
+	up_read(&dqopt->dqio_sem);
+
+	return 0;
+}
+
+/**
+ * ubifs_write_file_info - write quota file to device
+ * @sb: The superblock
+ * @type: Quota type
+ *
+ * We currently do not store any quota file on flash. Nothing to do here.
+ */
+static int ubifs_write_file_info(struct super_block *sb, int type)
+{
+	return 0;
+}
+
+/**
+ * ubifs_read_dquot - read dquot from device
+ * @dquot: The dquot entry to read
+ *
+ * For us this means finding the entry in the dquot tree.
+ */
+static int ubifs_read_dquot(struct dquot *dquot)
+{
+	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+	struct ubifs_info *c = dquot->dq_sb->s_fs_info;
+	struct ubifs_dqblk *ud;
+	int ret = 0;
+
+	down_read(&dqopt->dqio_sem);
+
+	ud = ubifs_dqblk_find(c, dquot->dq_id);
+	if (ud)
+		dquot->dq_dqb = ud->dqblk;
+	else
+		ret = -ENOENT;
+
+	up_read(&dqopt->dqio_sem);
+
+	return 0;
+}
+
+/**
+ * ubifs_write_dquot - write dquot to device
+ * @dquot: The dquot entry to read
+ *
+ * For us this means finding or creating the entry in the dquot tree and setting
+ * it to the dquots contents.
+ */
+static int ubifs_write_dquot(struct dquot *dquot)
+{
+	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+	struct ubifs_info *c = dquot->dq_sb->s_fs_info;
+	int ret = 0;
+	struct ubifs_dqblk *ud;
+
+	down_write(&dqopt->dqio_sem);
+
+	ud = ubifs_dqblk_get(c, dquot->dq_id);
+	if (!ud) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ud->dqblk = dquot->dq_dqb;
+
+out:
+	up_write(&dqopt->dqio_sem);
+
+	return ret;
+}
+
+/**
+ * ubifs_release_dquot - release memory associated to a dquot entry
+ * @dquot: The dquot entry
+ *
+ * Nothing to do here, we didn't allocate anything. Our data is freed at unmount
+ * time.
+ */
+static int ubifs_release_dquot(struct dquot *dquot)
+{
+	return 0;
+}
+
+/**
+ * ubifs_free_file_info - free memory allocated during reading the file info
+ * @sb: The superblock
+ * @type: Quota type
+ *
+ * Nothing to do here.
+ */
+static int ubifs_free_file_info(struct super_block *sb, int type)
+{
+	return 0;
+}
+
+static int ubifs_get_next_id(struct super_block *sb, struct kqid *qid)
+{
+	struct quota_info *dqopt = sb_dqopt(sb);
+	struct ubifs_info *c = sb->s_fs_info;
+	struct ubifs_dqblk *ud;
+	int ret = 0;
+
+	down_read(&dqopt->dqio_sem);
+
+	ud = ubifs_dqblk_find_next(c, *qid);
+	if (!ud) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	*qid = ud->kqid;
+out:
+	up_read(&dqopt->dqio_sem);
+
+	return ret;
+}
+
+static const struct quota_format_ops ubifs_format_ops = {
+	.check_quota_file	= ubifs_check_quota_file,
+	.read_file_info		= ubifs_read_file_info,
+	.write_file_info	= ubifs_write_file_info,
+	.free_file_info		= ubifs_free_file_info,
+	.read_dqblk		= ubifs_read_dquot,
+	.commit_dqblk		= ubifs_write_dquot,
+	.release_dqblk		= ubifs_release_dquot,
+	.get_next_id		= ubifs_get_next_id,
+};
+
+/**
+ * add_inode_quota - read quota informations for an inode
+ * @c: UBIFS file-system description object
+ * @zbr: The zbranch to read the inode from
+ *
+ * This reads the inode as referred to by @zbr from the medium and
+ * extracts the quota relevant informations. Returns 0 for success
+ * or a negative error code otherwise.
+ */
+static int add_inode_quota(struct ubifs_info *c, struct ubifs_zbranch *zbr)
+{
+	struct ubifs_ino_node *ino;
+	int err, type = key_type(c, &zbr->key);
+	struct kqid qid[MAXQUOTAS];
+	kprojid_t kprojid;
+	kgid_t kgid;
+	kuid_t kuid;
+	int i;
+
+	if (type != UBIFS_INO_KEY) {
+		ubifs_err(c, "%s called on non INO node %d", __func__, type);
+		return 0;
+	}
+
+	if (zbr->len < UBIFS_CH_SZ) {
+		ubifs_err(c, "bad leaf length %d (LEB %d:%d)",
+				zbr->len, zbr->lnum, zbr->offs);
+		return -EINVAL;
+	}
+
+	ino = kmalloc(zbr->len, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	err = ubifs_tnc_read_node(c, zbr, ino);
+	if (err) {
+		ubifs_err(c, "cannot read leaf node at LEB %d:%d, error %d",
+				zbr->lnum, zbr->offs, err);
+		goto out_free;
+	}
+
+	kuid = make_kuid(&init_user_ns, le32_to_cpu(ino->uid));
+	qid[USRQUOTA] = make_kqid_uid(kuid);
+
+	kgid = make_kgid(&init_user_ns, le32_to_cpu(ino->gid));
+	qid[GRPQUOTA] = make_kqid_gid(kgid);
+
+	kprojid = make_kprojid(&init_user_ns, le32_to_cpu(ino->projid));
+	qid[PRJQUOTA] = make_kqid_projid(kprojid);
+
+	for (i = 0; i < UBIFS_MAXQUOTAS; i++) {
+		struct ubifs_dqblk *ud;
+
+		ud = ubifs_dqblk_get(c, qid[i]);
+		if (!ud) {
+			err = -ENOMEM;
+			goto out_free;
+		}
+
+		if (S_ISREG(le32_to_cpu(ino->mode)))
+			ud->dqblk.dqb_curspace += le64_to_cpu(ino->size);
+		ud->dqblk.dqb_curinodes++;
+	}
+
+	err = 0;
+
+out_free:
+	kfree(ino);
+
+	return err;
+}
+
+/**
+ * get_next_parent_inum - get the next inum
+ * @c: UBIFS file-system description object
+ * @znode: The znode to start searching from
+ * @inum: The next inum returned here
+ *
+ * Helper function for ubifs_quota_walk_index(). If we know the next inum we
+ * find up the tree is still the same as we just handled we do not have to walk
+ * down the tree but can skip these branches. Returns 0 for success or -ENOENT
+ * when we can't go further to the upper-right but hit the root node instead.
+ */
+static int get_next_parent_inum(struct ubifs_info *c, struct ubifs_znode *znode,
+				ino_t *inum)
+{
+	struct ubifs_znode *zp;
+
+	while (1) {
+		int nn;
+
+		zp = znode->parent;
+		if (!zp)
+			return -ENOENT;
+
+		nn = znode->iip + 1;
+		znode = zp;
+
+		if (nn < znode->child_cnt) {
+			*inum = key_inum(c, &znode->zbranch[nn].key);
+			return 0;
+		}
+	}
+}
+
+/**
+ * ubifs_quota_walk_index - Collect quota info
+ * @c: UBIFS file-system description object
+ *
+ * This function walks the whole index and collects the quota usage information
+ * for all inodes. Returns 0 for success or a negative error code otherwise.
+ */
+static int ubifs_quota_walk_index(struct ubifs_info *c)
+{
+	int err;
+	struct ubifs_znode *znode;
+	int i, nn = 0;
+	ino_t inum = 0, pinum;
+
+	if (!c->zroot.znode) {
+		c->zroot.znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
+		if (IS_ERR(c->zroot.znode)) {
+			err = PTR_ERR(c->zroot.znode);
+			c->zroot.znode = NULL;
+			return err;
+		}
+	}
+
+	znode = c->zroot.znode;
+
+	while (1) {
+		while (znode->level != 0) {
+			znode = ubifs_get_znode(c, znode, nn);
+			if (IS_ERR(znode))
+				return PTR_ERR(znode);
+			nn = 0;
+		}
+
+		for (i = 0; i < znode->child_cnt; i++) {
+			if (inum == key_inum(c, &znode->zbranch[i].key))
+				continue;
+
+			add_inode_quota(c, &znode->zbranch[i]);
+			inum = key_inum(c, &znode->zbranch[i].key);
+		}
+
+		while (1) {
+			struct ubifs_znode *zp;
+
+			zp = znode->parent;
+			if (!zp)
+				return 0;
+
+			nn = znode->iip + 1;
+			znode = zp;
+
+			err = get_next_parent_inum(c, znode, &pinum);
+
+			/*
+			 * Optimization: When the next parent node is still for
+			 * the inode we just handled we can skip parsing our
+			 * children.
+			 */
+			if (!err && pinum == inum)
+				continue;
+
+			/*
+			 * Optimization: We can skip scanning all child nodes
+			 * which are for the same inode as we already looked at.
+			 */
+			while (nn < znode->child_cnt - 1 &&
+			       inum == key_inum(c, &znode->zbranch[nn + 1].key))
+				nn++;
+
+			if (nn < znode->child_cnt)
+				break;
+		}
+	}
+}
+
+/**
+ * ubifs_enable_quotas - enable quota
+ * @c: UBIFS file-system description object
+ *
+ * Enable usage tracking for all quota types.
+ */
+int ubifs_enable_quotas(struct ubifs_info *c)
+{
+	struct super_block *sb = c->vfs_sb;
+	struct quota_info *dqopt = sb_dqopt(sb);
+	int type;
+
+	if (!c->quota_enable)
+		return 0;
+
+	dqopt->flags |= DQUOT_QUOTA_SYS_FILE | DQUOT_NOLIST_DIRTY;
+
+	for (type = 0; type < UBIFS_MAXQUOTAS; type++) {
+		struct mem_dqinfo *info = sb_dqinfo(sb, type);
+		unsigned int flags = DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED;
+
+		dqopt->flags |= dquot_state_flag(flags, type);
+		dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
+		dqopt->ops[type] = &ubifs_format_ops;
+
+		info->dqi_max_spc_limit = 0x7fffffffffffffffLL;
+		info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
+
+		c->dqblk_tree[type] = RB_ROOT;
+	}
+
+	return ubifs_quota_walk_index(c);
+}
+
+/**
+ * ubifs_disable_quotas - disable quota
+ * @c: UBIFS file-system description object
+ *
+ * Disable quota for UBFIS.
+ */
+void ubifs_disable_quotas(struct ubifs_info *c)
+{
+	struct rb_node *n;
+	struct ubifs_dqblk *ud;
+	int type;
+
+	if (!c->quota_enable)
+		return;
+
+	dquot_disable(c->vfs_sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
+
+	for (type = 0; type < UBIFS_MAXQUOTAS; type++) {
+		while ((n = rb_first(&c->dqblk_tree[type]))) {
+			ud = rb_entry(n, struct ubifs_dqblk, rb);
+			rb_erase(n, &c->dqblk_tree[type]);
+			kfree(ud);
+		}
+	}
+}
+
+static int ubifs_get_projid(struct inode *inode, kprojid_t *projid)
+{
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	*projid = ui->projid;
+
+	return 0;
+}
+
+static const struct dquot_operations ubifs_dquot_operations = {
+	.write_dquot	= dquot_commit,
+	.acquire_dquot	= dquot_acquire,
+	.release_dquot	= dquot_release,
+	.mark_dirty	= dquot_mark_dquot_dirty,
+	.write_info	= dquot_commit_info,
+	.alloc_dquot	= dquot_alloc,
+	.destroy_dquot	= dquot_destroy,
+	.get_next_id	= dquot_get_next_id,
+	.get_projid	= ubifs_get_projid,
+};
+
+static const struct quotactl_ops ubifs_quotactl_ops = {
+	.get_state	= dquot_get_state,
+	.set_info	= dquot_set_dqinfo,
+	.get_dqblk	= dquot_get_dqblk,
+	.set_dqblk	= dquot_set_dqblk,
+	.get_nextdqblk	= dquot_get_next_dqblk,
+};
+
+/**
+ * ubifs_init_quota - init quota ops for UBIFS
+ * @c: UBIFS file-system description object
+ *
+ * This inits the quota operations for UBIFS
+ */
+void ubifs_init_quota(struct ubifs_info *c)
+{
+	struct super_block *sb = c->vfs_sb;
+
+	if (!c->quota_enable)
+		return;
+
+	sb->dq_op = &ubifs_dquot_operations;
+	sb->s_qcop = &ubifs_quotactl_ops;
+	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
+}
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index dc7e235b1a4a..3f20866b73db 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -151,6 +151,7 @@ struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
 
 	switch (inode->i_mode & S_IFMT) {
 	case S_IFREG:
+		inode_set_bytes(inode, ino->size);
 		inode->i_mapping->a_ops = &ubifs_file_address_operations;
 		inode->i_op = &ubifs_file_inode_operations;
 		inode->i_fop = &ubifs_file_operations;
@@ -344,6 +345,7 @@ static void ubifs_evict_inode(struct inode *inode)
 	if (is_bad_inode(inode))
 		goto out;
 
+	dquot_initialize(inode);
 	ui->ui_size = inode->i_size = 0;
 	err = ubifs_jnl_delete_inode(c, inode);
 	if (err)
@@ -353,7 +355,7 @@ static void ubifs_evict_inode(struct inode *inode)
 		 */
 		ubifs_err(c, "can't delete inode %lu, error %d",
 			  inode->i_ino, err);
-
+	dquot_free_inode(inode);
 out:
 	if (ui->dirty)
 		ubifs_release_dirty_inode_budget(c, ui);
@@ -363,6 +365,7 @@ static void ubifs_evict_inode(struct inode *inode)
 		smp_wmb();
 	}
 done:
+	dquot_drop(inode);
 	clear_inode(inode);
 	fscrypt_put_encryption_info(inode);
 }
@@ -425,6 +428,9 @@ static int ubifs_show_options(struct seq_file *s, struct dentry *root)
 	else if (c->mount_opts.chk_data_crc == 1)
 		seq_puts(s, ",no_chk_data_crc");
 
+	if (c->quota_enable)
+		seq_puts(s, ",quota");
+
 	if (c->mount_opts.override_compr) {
 		seq_printf(s, ",compr=%s",
 			   ubifs_compr_name(c, c->mount_opts.compr_type));
@@ -913,6 +919,13 @@ static int check_volume_empty(struct ubifs_info *c)
 	return 0;
 }
 
+#ifdef CONFIG_QUOTA
+static struct dquot **ubifs_get_dquots(struct inode *inode)
+{
+	return ubifs_inode(inode)->i_dquot;
+}
+#endif
+
 /*
  * UBIFS mount options.
  *
@@ -940,6 +953,7 @@ enum {
 	Opt_auth_key,
 	Opt_auth_hash_name,
 	Opt_ignore,
+	Opt_quota,
 	Opt_err,
 };
 
@@ -956,6 +970,7 @@ static const match_table_t tokens = {
 	{Opt_ignore, "ubi=%s"},
 	{Opt_ignore, "vol=%s"},
 	{Opt_assert, "assert=%s"},
+	{Opt_quota, "quota"},
 	{Opt_err, NULL},
 };
 
@@ -1090,6 +1105,15 @@ static int ubifs_parse_options(struct ubifs_info *c, char *options,
 			break;
 		case Opt_ignore:
 			break;
+#ifdef CONFIG_QUOTA
+		case Opt_quota:
+			c->quota_enable = true;
+			break;
+#else
+		case Opt_quota:
+			ubifs_err(c, "quota operations not supported");
+			break;
+#endif
 		default:
 		{
 			unsigned long flag;
@@ -1786,6 +1810,7 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 		 */
 		err = dbg_check_space_info(c);
 	}
+	c->vfs_sb->s_flags &= ~SB_RDONLY;
 
 	mutex_unlock(&c->umount_mutex);
 	return err;
@@ -1855,6 +1880,7 @@ static void ubifs_remount_ro(struct ubifs_info *c)
 	err = dbg_check_space_info(c);
 	if (err)
 		ubifs_ro_mode(c, err);
+	c->vfs_sb->s_flags |= SB_RDONLY;
 	mutex_unlock(&c->umount_mutex);
 }
 
@@ -1865,6 +1891,8 @@ static void ubifs_put_super(struct super_block *sb)
 
 	ubifs_msg(c, "un-mount UBI device %d", c->vi.ubi_num);
 
+	ubifs_disable_quotas(c);
+
 	/*
 	 * The following asserts are only valid if there has not been a failure
 	 * of the media. For example, there will be dirty inodes if we failed
@@ -1962,11 +1990,17 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
 		err = ubifs_remount_rw(c);
 		if (err)
 			return err;
+		err = dquot_resume(sb, -1);
+		if (err)
+			return err;
 	} else if (!c->ro_mount && (*flags & SB_RDONLY)) {
 		if (c->ro_error) {
 			ubifs_msg(c, "cannot re-mount R/O due to prior errors");
 			return -EROFS;
 		}
+		err = dquot_suspend(sb, -1);
+		if (err)
+			return err;
 		ubifs_remount_ro(c);
 	}
 
@@ -1997,6 +2031,9 @@ const struct super_operations ubifs_super_operations = {
 	.remount_fs    = ubifs_remount_fs,
 	.show_options  = ubifs_show_options,
 	.sync_fs       = ubifs_sync_fs,
+#ifdef CONFIG_QUOTA
+	.get_dquots    = ubifs_get_dquots,
+#endif
 };
 
 /**
@@ -2157,6 +2194,8 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 #endif
 	fscrypt_set_ops(sb, &ubifs_crypt_operations);
 
+	ubifs_init_quota(c);
+
 	mutex_lock(&c->umount_mutex);
 	err = mount_ubifs(c);
 	if (err) {
@@ -2171,6 +2210,10 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_umount;
 	}
 
+	err = ubifs_enable_quotas(c);
+	if (err)
+		goto out_umount;
+
 	sb->s_root = d_make_root(root);
 	if (!sb->s_root) {
 		err = -ENOMEM;
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 188fa036e655..624568365ad3 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -600,7 +600,7 @@ struct ubifs_znode *ubifs_get_znode(struct ubifs_info *c,
  * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
  * no next entry, or a negative error code otherwise.
  */
-static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
+int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
 {
 	struct ubifs_znode *znode = *zn;
 	int nn = *n;
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index fd9e52749ef7..884fce6c133e 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -27,6 +27,7 @@
 #include <linux/security.h>
 #include <linux/xattr.h>
 #include <linux/random.h>
+#include <linux/quotaops.h>
 #include <crypto/hash_info.h>
 #include <crypto/hash.h>
 #include <crypto/algapi.h>
@@ -157,6 +158,8 @@
 
 #define UBIFS_DEF_PROJID 0
 
+#define UBIFS_MAXQUOTAS 3
+
 /*
  * Lockdep classes for UBIFS inode @ui_mutex.
  */
@@ -416,6 +419,9 @@ struct ubifs_inode {
 	loff_t synced_i_size;
 	loff_t ui_size;
 	int flags;
+#ifdef CONFIG_QUOTA
+	struct dquot *i_dquot[UBIFS_MAXQUOTAS];
+#endif
 	kprojid_t projid;
 	pgoff_t last_page_read;
 	pgoff_t read_in_a_row;
@@ -1045,6 +1051,7 @@ struct ubifs_debug_info;
  * @rw_incompat: the media is not R/W compatible
  * @assert_action: action to take when a ubifs_assert() fails
  * @authenticated: flag indigating the FS is mounted in authenticated mode
+ * @quota_enable: If true, quota is enabled on this filesystem
  *
  * @tnc_mutex: protects the Tree Node Cache (TNC), @zroot, @cnext, @enext, and
  *             @calc_idx_sz
@@ -1386,6 +1393,9 @@ struct ubifs_info {
 	struct ubi_device_info di;
 	struct ubi_volume_info vi;
 
+	bool quota_enable;
+	struct rb_root dqblk_tree[UBIFS_MAXQUOTAS];
+
 	struct rb_root orph_tree;
 	struct list_head orph_list;
 	struct list_head orph_new;
@@ -2108,6 +2118,23 @@ static inline bool ubifs_crypt_is_encrypted(const struct inode *inode)
 	return ui->flags & UBIFS_CRYPT_FL;
 }
 
+/* quota.c */
+#ifdef CONFIG_QUOTA
+void ubifs_init_quota(struct ubifs_info *c);
+int ubifs_enable_quotas(struct ubifs_info *c);
+void ubifs_disable_quotas(struct ubifs_info *c);
+#else
+static inline void ubifs_init_quota(struct ubifs_info *c)
+{
+}
+static inline int ubifs_enable_quotas(struct ubifs_info *c)
+{
+	return 0;
+}
+static inline void ubifs_disable_quotas(struct ubifs_info *c)
+{
+}
+#endif
 /* Normal UBIFS messages */
 __printf(2, 3)
 void ubifs_msg(const struct ubifs_info *c, const char *fmt, ...);
-- 
2.20.1


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