LXR linux/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 */
  28enum zonefs_ztype {
  29        ZONEFS_ZTYPE_CNV,
  30        ZONEFS_ZTYPE_SEQ,
  31        ZONEFS_ZTYPE_MAX,
  32};
  33
  34static 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 */
  46struct 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
  85static 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
  97struct 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 */
 131enum 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 */
 168struct 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
 190static 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