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 */
29 enum zonefs_ztype {
30 ZONEFS_ZTYPE_CNV,
31 ZONEFS_ZTYPE_SEQ,
32 ZONEFS_ZTYPE_MAX,
33 };
34
zonefs_zone_type(struct blk_zone * zone)35 static 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 */
50 struct 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
ZONEFS_I(struct inode * inode)88 static 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
100 struct 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 */
134 enum 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 */
171 struct 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
ZONEFS_SB(struct super_block * sb)200 static 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
212 int zonefs_sysfs_register(struct super_block *sb);
213 void zonefs_sysfs_unregister(struct super_block *sb);
214 int zonefs_sysfs_init(void);
215 void zonefs_sysfs_exit(void);
216
217 #endif
218