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#include <linux/kobject.h>
 16
 17/*
 18 * Maximum length of file names: this only needs to be large enough to fit
 19 * the zone group directory names and a decimal zone number for file names.
 20 * 16 characters is plenty.
 21 */
 22#define ZONEFS_NAME_MAX		16
 23
 24/*
 25 * Zone types: ZONEFS_ZTYPE_SEQ is used for all sequential zone types
 26 * defined in linux/blkzoned.h, that is, BLK_ZONE_TYPE_SEQWRITE_REQ and
 27 * BLK_ZONE_TYPE_SEQWRITE_PREF.
 28 */
 29enum zonefs_ztype {
 30	ZONEFS_ZTYPE_CNV,
 31	ZONEFS_ZTYPE_SEQ,
 32	ZONEFS_ZTYPE_MAX,
 33};
 34
 35static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone)
 36{
 37	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
 38		return ZONEFS_ZTYPE_CNV;
 39	return ZONEFS_ZTYPE_SEQ;
 40}
 41
 42#define ZONEFS_ZONE_OPEN	(1U << 0)
 43#define ZONEFS_ZONE_ACTIVE	(1U << 1)
 44#define ZONEFS_ZONE_OFFLINE	(1U << 2)
 45#define ZONEFS_ZONE_READONLY	(1U << 3)
 46
 47/*
 48 * In-memory inode data.
 49 */
 50struct zonefs_inode_info {
 51	struct inode		i_vnode;
 52
 53	/* File zone type */
 54	enum zonefs_ztype	i_ztype;
 55
 56	/* File zone start sector (512B unit) */
 57	sector_t		i_zsector;
 58
 59	/* File zone write pointer position (sequential zones only) */
 60	loff_t			i_wpoffset;
 61
 62	/* File maximum size */
 63	loff_t			i_max_size;
 64
 65	/* File zone size */
 66	loff_t			i_zone_size;
 67
 68	/*
 69	 * To serialise fully against both syscall and mmap based IO and
 70	 * sequential file truncation, two locks are used. For serializing
 71	 * zonefs_seq_file_truncate() against zonefs_iomap_begin(), that is,
 72	 * file truncate operations against block mapping, i_truncate_mutex is
 73	 * used. i_truncate_mutex also protects against concurrent accesses
 74	 * and changes to the inode private data, and in particular changes to
 75	 * a sequential file size on completion of direct IO writes.
 76	 * Serialization of mmap read IOs with truncate and syscall IO
 77	 * operations is done with invalidate_lock in addition to
 78	 * i_truncate_mutex.  Only zonefs_seq_file_truncate() takes both lock
 79	 * (invalidate_lock first, i_truncate_mutex second).
 80	 */
 81	struct mutex		i_truncate_mutex;
 82
 83	/* guarded by i_truncate_mutex */
 84	unsigned int		i_wr_refcnt;
 85	unsigned int		i_flags;
 86};
 87
 88static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
 89{
 90	return container_of(inode, struct zonefs_inode_info, i_vnode);
 91}
 92
 93/*
 94 * On-disk super block (block 0).
 95 */
 96#define ZONEFS_LABEL_LEN	64
 97#define ZONEFS_UUID_SIZE	16
 98#define ZONEFS_SUPER_SIZE	4096
 99
100struct zonefs_super {
101
102	/* Magic number */
103	__le32		s_magic;
104
105	/* Checksum */
106	__le32		s_crc;
107
108	/* Volume label */
109	char		s_label[ZONEFS_LABEL_LEN];
110
111	/* 128-bit uuid */
112	__u8		s_uuid[ZONEFS_UUID_SIZE];
113
114	/* Features */
115	__le64		s_features;
116
117	/* UID/GID to use for files */
118	__le32		s_uid;
119	__le32		s_gid;
120
121	/* File permissions */
122	__le32		s_perm;
123
124	/* Padding to ZONEFS_SUPER_SIZE bytes */
125	__u8		s_reserved[3988];
126
127} __packed;
128
129/*
130 * Feature flags: specified in the s_features field of the on-disk super
131 * block struct zonefs_super and in-memory in the s_feartures field of
132 * struct zonefs_sb_info.
133 */
134enum zonefs_features {
135	/*
136	 * Aggregate contiguous conventional zones into a single file.
137	 */
138	ZONEFS_F_AGGRCNV = 1ULL << 0,
139	/*
140	 * Use super block specified UID for files instead of default 0.
141	 */
142	ZONEFS_F_UID = 1ULL << 1,
143	/*
144	 * Use super block specified GID for files instead of default 0.
145	 */
146	ZONEFS_F_GID = 1ULL << 2,
147	/*
148	 * Use super block specified file permissions instead of default 640.
149	 */
150	ZONEFS_F_PERM = 1ULL << 3,
151};
152
153#define ZONEFS_F_DEFINED_FEATURES \
154	(ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
155
156/*
157 * Mount options for zone write pointer error handling.
158 */
159#define ZONEFS_MNTOPT_ERRORS_RO		(1 << 0) /* Make zone file readonly */
160#define ZONEFS_MNTOPT_ERRORS_ZRO	(1 << 1) /* Make zone file offline */
161#define ZONEFS_MNTOPT_ERRORS_ZOL	(1 << 2) /* Make zone file offline */
162#define ZONEFS_MNTOPT_ERRORS_REPAIR	(1 << 3) /* Remount read-only */
163#define ZONEFS_MNTOPT_ERRORS_MASK	\
164	(ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \
165	 ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR)
166#define ZONEFS_MNTOPT_EXPLICIT_OPEN	(1 << 4) /* Explicit open/close of zones on open/close */
167
168/*
169 * In-memory Super block information.
170 */
171struct zonefs_sb_info {
172
173	unsigned long		s_mount_opts;
174
175	spinlock_t		s_lock;
176
177	unsigned long long	s_features;
178	kuid_t			s_uid;
179	kgid_t			s_gid;
180	umode_t			s_perm;
181	uuid_t			s_uuid;
182	unsigned int		s_zone_sectors_shift;
183
184	unsigned int		s_nr_files[ZONEFS_ZTYPE_MAX];
185
186	loff_t			s_blocks;
187	loff_t			s_used_blocks;
188
189	unsigned int		s_max_wro_seq_files;
190	atomic_t		s_wro_seq_files;
191
192	unsigned int		s_max_active_seq_files;
193	atomic_t		s_active_seq_files;
194
195	bool			s_sysfs_registered;
196	struct kobject		s_kobj;
197	struct completion	s_kobj_unregister;
198};
199
200static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
201{
202	return sb->s_fs_info;
203}
204
205#define zonefs_info(sb, format, args...)	\
206	pr_info("zonefs (%s): " format, sb->s_id, ## args)
207#define zonefs_err(sb, format, args...)		\
208	pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args)
209#define zonefs_warn(sb, format, args...)	\
210	pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
211
212int zonefs_sysfs_register(struct super_block *sb);
213void zonefs_sysfs_unregister(struct super_block *sb);
214int zonefs_sysfs_init(void);
215void zonefs_sysfs_exit(void);
216
217#endif