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