1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Simple zone file system for zoned block devices.
  4 *
  5 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
  6 */
  7#ifndef __ZONEFS_H__
  8#define __ZONEFS_H__
  9
 10#include <linux/fs.h>
 11#include <linux/magic.h>
 12#include <linux/uuid.h>
 13#include <linux/mutex.h>
 14#include <linux/rwsem.h>
 15
 16/*
 17 * Maximum length of file names: this only needs to be large enough to fit
 18 * the zone group directory names and a decimal zone number for file names.
 19 * 16 characters is plenty.
 20 */
 21#define ZONEFS_NAME_MAX		16
 22
 23/*
 24 * Zone types: ZONEFS_ZTYPE_SEQ is used for all sequential zone types
 25 * defined in linux/blkzoned.h, that is, BLK_ZONE_TYPE_SEQWRITE_REQ and
 26 * BLK_ZONE_TYPE_SEQWRITE_PREF.
 27 */
 28enum zonefs_ztype {
 29	ZONEFS_ZTYPE_CNV,
 30	ZONEFS_ZTYPE_SEQ,
 31	ZONEFS_ZTYPE_MAX,
 32};
 33
 34static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone)
 35{
 36	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
 37		return ZONEFS_ZTYPE_CNV;
 38	return ZONEFS_ZTYPE_SEQ;
 39}
 40
 41/*
 42 * In-memory inode data.
 43 */
 44struct zonefs_inode_info {
 45	struct inode		i_vnode;
 46
 47	/* File zone type */
 48	enum zonefs_ztype	i_ztype;
 49
 50	/* File zone start sector (512B unit) */
 51	sector_t		i_zsector;
 52
 53	/* File zone write pointer position (sequential zones only) */
 54	loff_t			i_wpoffset;
 55
 56	/* File maximum size */
 57	loff_t			i_max_size;
 58
 59	/* File zone size */
 60	loff_t			i_zone_size;
 61
 62	/*
 63	 * To serialise fully against both syscall and mmap based IO and
 64	 * sequential file truncation, two locks are used. For serializing
 65	 * zonefs_seq_file_truncate() against zonefs_iomap_begin(), that is,
 66	 * file truncate operations against block mapping, i_truncate_mutex is
 67	 * used. i_truncate_mutex also protects against concurrent accesses
 68	 * and changes to the inode private data, and in particular changes to
 69	 * a sequential file size on completion of direct IO writes.
 70	 * Serialization of mmap read IOs with truncate and syscall IO
 71	 * operations is done with i_mmap_sem in addition to i_truncate_mutex.
 72	 * Only zonefs_seq_file_truncate() takes both lock (i_mmap_sem first,
 73	 * i_truncate_mutex second).
 74	 */
 75	struct mutex		i_truncate_mutex;
 76	struct rw_semaphore	i_mmap_sem;
 77};
 78
 79static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
 80{
 81	return container_of(inode, struct zonefs_inode_info, i_vnode);
 82}
 83
 84/*
 85 * On-disk super block (block 0).
 86 */
 87#define ZONEFS_LABEL_LEN	64
 88#define ZONEFS_UUID_SIZE	16
 89#define ZONEFS_SUPER_SIZE	4096
 90
 91struct zonefs_super {
 92
 93	/* Magic number */
 94	__le32		s_magic;
 95
 96	/* Checksum */
 97	__le32		s_crc;
 98
 99	/* Volume label */
100	char		s_label[ZONEFS_LABEL_LEN];
101
102	/* 128-bit uuid */
103	__u8		s_uuid[ZONEFS_UUID_SIZE];
104
105	/* Features */
106	__le64		s_features;
107
108	/* UID/GID to use for files */
109	__le32		s_uid;
110	__le32		s_gid;
111
112	/* File permissions */
113	__le32		s_perm;
114
115	/* Padding to ZONEFS_SUPER_SIZE bytes */
116	__u8		s_reserved[3988];
117
118} __packed;
119
120/*
121 * Feature flags: specified in the s_features field of the on-disk super
122 * block struct zonefs_super and in-memory in the s_feartures field of
123 * struct zonefs_sb_info.
124 */
125enum zonefs_features {
126	/*
127	 * Aggregate contiguous conventional zones into a single file.
128	 */
129	ZONEFS_F_AGGRCNV = 1ULL << 0,
130	/*
131	 * Use super block specified UID for files instead of default 0.
132	 */
133	ZONEFS_F_UID = 1ULL << 1,
134	/*
135	 * Use super block specified GID for files instead of default 0.
136	 */
137	ZONEFS_F_GID = 1ULL << 2,
138	/*
139	 * Use super block specified file permissions instead of default 640.
140	 */
141	ZONEFS_F_PERM = 1ULL << 3,
142};
143
144#define ZONEFS_F_DEFINED_FEATURES \
145	(ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
146
147/*
148 * Mount options for zone write pointer error handling.
149 */
150#define ZONEFS_MNTOPT_ERRORS_RO		(1 << 0) /* Make zone file readonly */
151#define ZONEFS_MNTOPT_ERRORS_ZRO	(1 << 1) /* Make zone file offline */
152#define ZONEFS_MNTOPT_ERRORS_ZOL	(1 << 2) /* Make zone file offline */
153#define ZONEFS_MNTOPT_ERRORS_REPAIR	(1 << 3) /* Remount read-only */
154#define ZONEFS_MNTOPT_ERRORS_MASK	\
155	(ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \
156	 ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR)
157
158/*
159 * In-memory Super block information.
160 */
161struct zonefs_sb_info {
162
163	unsigned long		s_mount_opts;
164
165	spinlock_t		s_lock;
166
167	unsigned long long	s_features;
168	kuid_t			s_uid;
169	kgid_t			s_gid;
170	umode_t			s_perm;
171	uuid_t			s_uuid;
172	unsigned int		s_zone_sectors_shift;
173
174	unsigned int		s_nr_files[ZONEFS_ZTYPE_MAX];
175
176	loff_t			s_blocks;
177	loff_t			s_used_blocks;
178};
179
180static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
181{
182	return sb->s_fs_info;
183}
184
185#define zonefs_info(sb, format, args...)	\
186	pr_info("zonefs (%s): " format, sb->s_id, ## args)
187#define zonefs_err(sb, format, args...)		\
188	pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args)
189#define zonefs_warn(sb, format, args...)	\
190	pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
191
192#endif