ext4: add project quota support

This patch adds mount options for enabling/disabling project quota
accounting and enforcement. A new specific inode is also used for
project quota accounting.

[ Includes fix from Dan Carpenter to crrect error checking from dqget(). ]
Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>

fs/ext4/ext4.h

@@ -1261,7 +1261,7 @@ struct ext4_super_block {
 #endif
 
 /* Number of quota types we support */
-#define EXT4_MAXQUOTAS 2
+#define EXT4_MAXQUOTAS 3
 
 /*
  * fourth extended-fs super-block data in memory

fs/ext4/super.c

@@ -1097,8 +1097,8 @@ static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
 }
 
 #ifdef CONFIG_QUOTA
-#define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
-#define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
+static char *quotatypes[] = INITQFNAMES;
+#define QTYPE2NAME(t) (quotatypes[t])
 
 static int ext4_write_dquot(struct dquot *dquot);
 static int ext4_acquire_dquot(struct dquot *dquot);
@@ -2558,6 +2558,12 @@ static int ext4_feature_set_ok(struct super_block *sb, int readonly)
 			 "without CONFIG_QUOTA");
 		return 0;
 	}
+	if (ext4_has_feature_project(sb) && !readonly) {
+		ext4_msg(sb, KERN_ERR,
+			 "Filesystem with project quota feature cannot be mounted RDWR "
+			 "without CONFIG_QUOTA");
+		return 0;
+	}
 #endif  /* CONFIG_QUOTA */
 	return 1;
 }
@@ -3686,7 +3692,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		sb->s_qcop = &dquot_quotactl_sysfile_ops;
 	else
 		sb->s_qcop = &ext4_qctl_operations;
-	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
+	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
 #endif
 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
 
@@ -4822,6 +4828,48 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 	return err;
 }
 
+#ifdef CONFIG_QUOTA
+static int ext4_statfs_project(struct super_block *sb,
+			       kprojid_t projid, struct kstatfs *buf)
+{
+	struct kqid qid;
+	struct dquot *dquot;
+	u64 limit;
+	u64 curblock;
+
+	qid = make_kqid_projid(projid);
+	dquot = dqget(sb, qid);
+	if (IS_ERR(dquot))
+		return PTR_ERR(dquot);
+	spin_lock(&dq_data_lock);
+
+	limit = (dquot->dq_dqb.dqb_bsoftlimit ?
+		 dquot->dq_dqb.dqb_bsoftlimit :
+		 dquot->dq_dqb.dqb_bhardlimit) >> sb->s_blocksize_bits;
+	if (limit && buf->f_blocks > limit) {
+		curblock = dquot->dq_dqb.dqb_curspace >> sb->s_blocksize_bits;
+		buf->f_blocks = limit;
+		buf->f_bfree = buf->f_bavail =
+			(buf->f_blocks > curblock) ?
+			 (buf->f_blocks - curblock) : 0;
+	}
+
+	limit = dquot->dq_dqb.dqb_isoftlimit ?
+		dquot->dq_dqb.dqb_isoftlimit :
+		dquot->dq_dqb.dqb_ihardlimit;
+	if (limit && buf->f_files > limit) {
+		buf->f_files = limit;
+		buf->f_ffree =
+			(buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
+			 (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
+	}
+
+	spin_unlock(&dq_data_lock);
+	dqput(dquot);
+	return 0;
+}
+#endif
+
 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
@@ -4854,6 +4902,11 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
 
+#ifdef CONFIG_QUOTA
+	if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
+	    sb_has_quota_limits_enabled(sb, PRJQUOTA))
+		ext4_statfs_project(sb, EXT4_I(dentry->d_inode)->i_projid, buf);
+#endif
 	return 0;
 }
 
@@ -5018,7 +5071,8 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
 	struct inode *qf_inode;
 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
-		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
 	};
 
 	BUG_ON(!ext4_has_feature_quota(sb));
@@ -5046,7 +5100,8 @@ static int ext4_enable_quotas(struct super_block *sb)
 	int type, err = 0;
 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
-		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
 	};
 
 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;