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 i_mmap_sem in addition to i_truncate_mutex.
74 * Only zonefs_seq_file_truncate() takes both lock (i_mmap_sem first,
75 * i_truncate_mutex second).
76 */
77 struct mutex i_truncate_mutex;
78 struct rw_semaphore i_mmap_sem;
79
80 /* guarded by i_truncate_mutex */
81 unsigned int i_wr_refcnt;
82 unsigned int i_flags;
83 };
84
ZONEFS_I(struct inode * inode)85 static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
86 {
87 return container_of(inode, struct zonefs_inode_info, i_vnode);
88 }
89
90 /*
91 * On-disk super block (block 0).
92 */
93 #define ZONEFS_LABEL_LEN 64
94 #define ZONEFS_UUID_SIZE 16
95 #define ZONEFS_SUPER_SIZE 4096
96
97 struct zonefs_super {
98
99 /* Magic number */
100 __le32 s_magic;
101
102 /* Checksum */
103 __le32 s_crc;
104
105 /* Volume label */
106 char s_label[ZONEFS_LABEL_LEN];
107
108 /* 128-bit uuid */
109 __u8 s_uuid[ZONEFS_UUID_SIZE];
110
111 /* Features */
112 __le64 s_features;
113
114 /* UID/GID to use for files */
115 __le32 s_uid;
116 __le32 s_gid;
117
118 /* File permissions */
119 __le32 s_perm;
120
121 /* Padding to ZONEFS_SUPER_SIZE bytes */
122 __u8 s_reserved[3988];
123
124 } __packed;
125
126 /*
127 * Feature flags: specified in the s_features field of the on-disk super
128 * block struct zonefs_super and in-memory in the s_feartures field of
129 * struct zonefs_sb_info.
130 */
131 enum zonefs_features {
132 /*
133 * Aggregate contiguous conventional zones into a single file.
134 */
135 ZONEFS_F_AGGRCNV = 1ULL << 0,
136 /*
137 * Use super block specified UID for files instead of default 0.
138 */
139 ZONEFS_F_UID = 1ULL << 1,
140 /*
141 * Use super block specified GID for files instead of default 0.
142 */
143 ZONEFS_F_GID = 1ULL << 2,
144 /*
145 * Use super block specified file permissions instead of default 640.
146 */
147 ZONEFS_F_PERM = 1ULL << 3,
148 };
149
150 #define ZONEFS_F_DEFINED_FEATURES \
151 (ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
152
153 /*
154 * Mount options for zone write pointer error handling.
155 */
156 #define ZONEFS_MNTOPT_ERRORS_RO (1 << 0) /* Make zone file readonly */
157 #define ZONEFS_MNTOPT_ERRORS_ZRO (1 << 1) /* Make zone file offline */
158 #define ZONEFS_MNTOPT_ERRORS_ZOL (1 << 2) /* Make zone file offline */
159 #define ZONEFS_MNTOPT_ERRORS_REPAIR (1 << 3) /* Remount read-only */
160 #define ZONEFS_MNTOPT_ERRORS_MASK \
161 (ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \
162 ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR)
163 #define ZONEFS_MNTOPT_EXPLICIT_OPEN (1 << 4) /* Explicit open/close of zones on open/close */
164
165 /*
166 * In-memory Super block information.
167 */
168 struct zonefs_sb_info {
169
170 unsigned long s_mount_opts;
171
172 spinlock_t s_lock;
173
174 unsigned long long s_features;
175 kuid_t s_uid;
176 kgid_t s_gid;
177 umode_t s_perm;
178 uuid_t s_uuid;
179 unsigned int s_zone_sectors_shift;
180
181 unsigned int s_nr_files[ZONEFS_ZTYPE_MAX];
182
183 loff_t s_blocks;
184 loff_t s_used_blocks;
185
186 unsigned int s_max_open_zones;
187 atomic_t s_open_zones;
188 };
189
ZONEFS_SB(struct super_block * sb)190 static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
191 {
192 return sb->s_fs_info;
193 }
194
195 #define zonefs_info(sb, format, args...) \
196 pr_info("zonefs (%s): " format, sb->s_id, ## args)
197 #define zonefs_err(sb, format, args...) \
198 pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args)
199 #define zonefs_warn(sb, format, args...) \
200 pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
201
202 #endif
203