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 #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
  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
 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