1 files changed, 189 insertions, 0 deletions
diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h
new file mode 100644
index 000000000000..ad17fef7ce91
--- /dev/null
+++ b/fs/zonefs/zonefs.h
@@ -0,0 +1,189 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Simple zone file system for zoned block devices.
+ *
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ */
+#ifndef __ZONEFS_H__
+#define __ZONEFS_H__
+
+#include <linux/fs.h>
+#include <linux/magic.h>
+#include <linux/uuid.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+
+/*
+ * Maximum length of file names: this only needs to be large enough to fit
+ * the zone group directory names and a decimal zone number for file names.
+ * 16 characters is plenty.
+ */
+#define ZONEFS_NAME_MAX		16
+
+/*
+ * Zone types: ZONEFS_ZTYPE_SEQ is used for all sequential zone types
+ * defined in linux/blkzoned.h, that is, BLK_ZONE_TYPE_SEQWRITE_REQ and
+ * BLK_ZONE_TYPE_SEQWRITE_PREF.
+ */
+enum zonefs_ztype {
+	ZONEFS_ZTYPE_CNV,
+	ZONEFS_ZTYPE_SEQ,
+	ZONEFS_ZTYPE_MAX,
+};
+
+static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone)
+{
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return ZONEFS_ZTYPE_CNV;
+	return ZONEFS_ZTYPE_SEQ;
+}
+
+/*
+ * In-memory inode data.
+ */
+struct zonefs_inode_info {
+	struct inode		i_vnode;
+
+	/* File zone type */
+	enum zonefs_ztype	i_ztype;
+
+	/* File zone start sector (512B unit) */
+	sector_t		i_zsector;
+
+	/* File zone write pointer position (sequential zones only) */
+	loff_t			i_wpoffset;
+
+	/* File maximum size */
+	loff_t			i_max_size;
+
+	/*
+	 * To serialise fully against both syscall and mmap based IO and
+	 * sequential file truncation, two locks are used. For serializing
+	 * zonefs_seq_file_truncate() against zonefs_iomap_begin(), that is,
+	 * file truncate operations against block mapping, i_truncate_mutex is
+	 * used. i_truncate_mutex also protects against concurrent accesses
+	 * and changes to the inode private data, and in particular changes to
+	 * a sequential file size on completion of direct IO writes.
+	 * Serialization of mmap read IOs with truncate and syscall IO
+	 * operations is done with i_mmap_sem in addition to i_truncate_mutex.
+	 * Only zonefs_seq_file_truncate() takes both lock (i_mmap_sem first,
+	 * i_truncate_mutex second).
+	 */
+	struct mutex		i_truncate_mutex;
+	struct rw_semaphore	i_mmap_sem;
+};
+
+static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
+{
+	return container_of(inode, struct zonefs_inode_info, i_vnode);
+}
+
+/*
+ * On-disk super block (block 0).
+ */
+#define ZONEFS_LABEL_LEN	64
+#define ZONEFS_UUID_SIZE	16
+#define ZONEFS_SUPER_SIZE	4096
+
+struct zonefs_super {
+
+	/* Magic number */
+	__le32		s_magic;
+
+	/* Checksum */
+	__le32		s_crc;
+
+	/* Volume label */
+	char		s_label[ZONEFS_LABEL_LEN];
+
+	/* 128-bit uuid */
+	__u8		s_uuid[ZONEFS_UUID_SIZE];
+
+	/* Features */
+	__le64		s_features;
+
+	/* UID/GID to use for files */
+	__le32		s_uid;
+	__le32		s_gid;
+
+	/* File permissions */
+	__le32		s_perm;
+
+	/* Padding to ZONEFS_SUPER_SIZE bytes */
+	__u8		s_reserved[3988];
+
+} __packed;
+
+/*
+ * Feature flags: specified in the s_features field of the on-disk super
+ * block struct zonefs_super and in-memory in the s_feartures field of
+ * struct zonefs_sb_info.
+ */
+enum zonefs_features {
+	/*
+	 * Aggregate contiguous conventional zones into a single file.
+	 */
+	ZONEFS_F_AGGRCNV = 1ULL << 0,
+	/*
+	 * Use super block specified UID for files instead of default 0.
+	 */
+	ZONEFS_F_UID = 1ULL << 1,
+	/*
+	 * Use super block specified GID for files instead of default 0.
+	 */
+	ZONEFS_F_GID = 1ULL << 2,
+	/*
+	 * Use super block specified file permissions instead of default 640.
+	 */
+	ZONEFS_F_PERM = 1ULL << 3,
+};
+
+#define ZONEFS_F_DEFINED_FEATURES \
+	(ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
+
+/*
+ * Mount options for zone write pointer error handling.
+ */
+#define ZONEFS_MNTOPT_ERRORS_RO		(1 << 0) /* Make zone file readonly */
+#define ZONEFS_MNTOPT_ERRORS_ZRO	(1 << 1) /* Make zone file offline */
+#define ZONEFS_MNTOPT_ERRORS_ZOL	(1 << 2) /* Make zone file offline */
+#define ZONEFS_MNTOPT_ERRORS_REPAIR	(1 << 3) /* Remount read-only */
+#define ZONEFS_MNTOPT_ERRORS_MASK	\
+	(ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \
+	 ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR)
+
+/*
+ * In-memory Super block information.
+ */
+struct zonefs_sb_info {
+
+	unsigned long		s_mount_opts;
+
+	spinlock_t		s_lock;
+
+	unsigned long long	s_features;
+	kuid_t			s_uid;
+	kgid_t			s_gid;
+	umode_t			s_perm;
+	uuid_t			s_uuid;
+	unsigned int		s_zone_sectors_shift;
+
+	unsigned int		s_nr_files[ZONEFS_ZTYPE_MAX];
+
+	loff_t			s_blocks;
+	loff_t			s_used_blocks;
+};
+
+static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+#define zonefs_info(sb, format, args...)	\
+	pr_info("zonefs (%s): " format, sb->s_id, ## args)
+#define zonefs_err(sb, format, args...)		\
+	pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args)
+#define zonefs_warn(sb, format, args...)	\
+	pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
+
+#endif