fs/zonefs/zonefs.h

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