v4.19.13 snapshot.
diff --git a/fs/xfs/xfs_dquot.h b/fs/xfs/xfs_dquot.h
new file mode 100644
index 0000000..64bd864
--- /dev/null
+++ b/fs/xfs/xfs_dquot.h
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#ifndef __XFS_DQUOT_H__
+#define __XFS_DQUOT_H__
+
+/*
+ * Dquots are structures that hold quota information about a user or a group,
+ * much like inodes are for files. In fact, dquots share many characteristics
+ * with inodes. However, dquots can also be a centralized resource, relative
+ * to a collection of inodes. In this respect, dquots share some characteristics
+ * of the superblock.
+ * XFS dquots exploit both those in its algorithms. They make every attempt
+ * to not be a bottleneck when quotas are on and have minimal impact, if any,
+ * when quotas are off.
+ */
+
+struct xfs_mount;
+struct xfs_trans;
+
+enum {
+	XFS_QLOWSP_1_PCNT = 0,
+	XFS_QLOWSP_3_PCNT,
+	XFS_QLOWSP_5_PCNT,
+	XFS_QLOWSP_MAX
+};
+
+/*
+ * The incore dquot structure
+ */
+typedef struct xfs_dquot {
+	uint		 dq_flags;	/* various flags (XFS_DQ_*) */
+	struct list_head q_lru;		/* global free list of dquots */
+	struct xfs_mount*q_mount;	/* filesystem this relates to */
+	struct xfs_trans*q_transp;	/* trans this belongs to currently */
+	uint		 q_nrefs;	/* # active refs from inodes */
+	xfs_daddr_t	 q_blkno;	/* blkno of dquot buffer */
+	int		 q_bufoffset;	/* off of dq in buffer (# dquots) */
+	xfs_fileoff_t	 q_fileoffset;	/* offset in quotas file */
+
+	xfs_disk_dquot_t q_core;	/* actual usage & quotas */
+	xfs_dq_logitem_t q_logitem;	/* dquot log item */
+	xfs_qcnt_t	 q_res_bcount;	/* total regular nblks used+reserved */
+	xfs_qcnt_t	 q_res_icount;	/* total inos allocd+reserved */
+	xfs_qcnt_t	 q_res_rtbcount;/* total realtime blks used+reserved */
+	xfs_qcnt_t	 q_prealloc_lo_wmark;/* prealloc throttle wmark */
+	xfs_qcnt_t	 q_prealloc_hi_wmark;/* prealloc disabled wmark */
+	int64_t		 q_low_space[XFS_QLOWSP_MAX];
+	struct mutex	 q_qlock;	/* quota lock */
+	struct completion q_flush;	/* flush completion queue */
+	atomic_t          q_pincount;	/* dquot pin count */
+	wait_queue_head_t q_pinwait;	/* dquot pinning wait queue */
+} xfs_dquot_t;
+
+/*
+ * Lock hierarchy for q_qlock:
+ *	XFS_QLOCK_NORMAL is the implicit default,
+ * 	XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2
+ */
+enum {
+	XFS_QLOCK_NORMAL = 0,
+	XFS_QLOCK_NESTED,
+};
+
+/*
+ * Manage the q_flush completion queue embedded in the dquot.  This completion
+ * queue synchronizes processes attempting to flush the in-core dquot back to
+ * disk.
+ */
+static inline void xfs_dqflock(xfs_dquot_t *dqp)
+{
+	wait_for_completion(&dqp->q_flush);
+}
+
+static inline bool xfs_dqflock_nowait(xfs_dquot_t *dqp)
+{
+	return try_wait_for_completion(&dqp->q_flush);
+}
+
+static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
+{
+	complete(&dqp->q_flush);
+}
+
+static inline int xfs_dqlock_nowait(struct xfs_dquot *dqp)
+{
+	return mutex_trylock(&dqp->q_qlock);
+}
+
+static inline void xfs_dqlock(struct xfs_dquot *dqp)
+{
+	mutex_lock(&dqp->q_qlock);
+}
+
+static inline void xfs_dqunlock(struct xfs_dquot *dqp)
+{
+	mutex_unlock(&dqp->q_qlock);
+}
+
+static inline int xfs_this_quota_on(struct xfs_mount *mp, int type)
+{
+	switch (type & XFS_DQ_ALLTYPES) {
+	case XFS_DQ_USER:
+		return XFS_IS_UQUOTA_ON(mp);
+	case XFS_DQ_GROUP:
+		return XFS_IS_GQUOTA_ON(mp);
+	case XFS_DQ_PROJ:
+		return XFS_IS_PQUOTA_ON(mp);
+	default:
+		return 0;
+	}
+}
+
+static inline xfs_dquot_t *xfs_inode_dquot(struct xfs_inode *ip, int type)
+{
+	switch (type & XFS_DQ_ALLTYPES) {
+	case XFS_DQ_USER:
+		return ip->i_udquot;
+	case XFS_DQ_GROUP:
+		return ip->i_gdquot;
+	case XFS_DQ_PROJ:
+		return ip->i_pdquot;
+	default:
+		return NULL;
+	}
+}
+
+/*
+ * Check whether a dquot is under low free space conditions. We assume the quota
+ * is enabled and enforced.
+ */
+static inline bool xfs_dquot_lowsp(struct xfs_dquot *dqp)
+{
+	int64_t freesp;
+
+	freesp = be64_to_cpu(dqp->q_core.d_blk_hardlimit) - dqp->q_res_bcount;
+	if (freesp < dqp->q_low_space[XFS_QLOWSP_1_PCNT])
+		return true;
+
+	return false;
+}
+
+#define XFS_DQ_IS_LOCKED(dqp)	(mutex_is_locked(&((dqp)->q_qlock)))
+#define XFS_DQ_IS_DIRTY(dqp)	((dqp)->dq_flags & XFS_DQ_DIRTY)
+#define XFS_QM_ISUDQ(dqp)	((dqp)->dq_flags & XFS_DQ_USER)
+#define XFS_QM_ISPDQ(dqp)	((dqp)->dq_flags & XFS_DQ_PROJ)
+#define XFS_QM_ISGDQ(dqp)	((dqp)->dq_flags & XFS_DQ_GROUP)
+
+extern void		xfs_qm_dqdestroy(xfs_dquot_t *);
+extern int		xfs_qm_dqflush(struct xfs_dquot *, struct xfs_buf **);
+extern void		xfs_qm_dqunpin_wait(xfs_dquot_t *);
+extern void		xfs_qm_adjust_dqtimers(xfs_mount_t *,
+					xfs_disk_dquot_t *);
+extern void		xfs_qm_adjust_dqlimits(struct xfs_mount *,
+					       struct xfs_dquot *);
+extern xfs_dqid_t	xfs_qm_id_for_quotatype(struct xfs_inode *ip,
+					uint type);
+extern int		xfs_qm_dqget(struct xfs_mount *mp, xfs_dqid_t id,
+					uint type, bool can_alloc,
+					struct xfs_dquot **dqpp);
+extern int		xfs_qm_dqget_inode(struct xfs_inode *ip, uint type,
+					bool can_alloc,
+					struct xfs_dquot **dqpp);
+extern int		xfs_qm_dqget_next(struct xfs_mount *mp, xfs_dqid_t id,
+					uint type, struct xfs_dquot **dqpp);
+extern int		xfs_qm_dqget_uncached(struct xfs_mount *mp,
+					xfs_dqid_t id, uint type,
+					struct xfs_dquot **dqpp);
+extern void		xfs_qm_dqput(xfs_dquot_t *);
+
+extern void		xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
+
+extern void		xfs_dquot_set_prealloc_limits(struct xfs_dquot *);
+
+static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
+{
+	xfs_dqlock(dqp);
+	dqp->q_nrefs++;
+	xfs_dqunlock(dqp);
+	return dqp;
+}
+
+typedef int (*xfs_qm_dqiterate_fn)(struct xfs_dquot *dq, uint dqtype,
+		void *priv);
+int xfs_qm_dqiterate(struct xfs_mount *mp, uint dqtype,
+		xfs_qm_dqiterate_fn iter_fn, void *priv);
+
+#endif /* __XFS_DQUOT_H__ */