190 lines
4.7 KiB
C
190 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Simple zone file system for zoned block devices.
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*
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* Copyright (C) 2019 Western Digital Corporation or its affiliates.
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*/
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#ifndef __ZONEFS_H__
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#define __ZONEFS_H__
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#include <linux/fs.h>
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#include <linux/magic.h>
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#include <linux/uuid.h>
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#include <linux/mutex.h>
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#include <linux/rwsem.h>
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/*
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* Maximum length of file names: this only needs to be large enough to fit
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* the zone group directory names and a decimal zone number for file names.
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* 16 characters is plenty.
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*/
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#define ZONEFS_NAME_MAX 16
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/*
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* Zone types: ZONEFS_ZTYPE_SEQ is used for all sequential zone types
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* defined in linux/blkzoned.h, that is, BLK_ZONE_TYPE_SEQWRITE_REQ and
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* BLK_ZONE_TYPE_SEQWRITE_PREF.
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*/
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enum zonefs_ztype {
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ZONEFS_ZTYPE_CNV,
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ZONEFS_ZTYPE_SEQ,
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ZONEFS_ZTYPE_MAX,
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};
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static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone)
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{
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if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
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return ZONEFS_ZTYPE_CNV;
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return ZONEFS_ZTYPE_SEQ;
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}
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/*
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* In-memory inode data.
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*/
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struct zonefs_inode_info {
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struct inode i_vnode;
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/* File zone type */
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enum zonefs_ztype i_ztype;
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/* File zone start sector (512B unit) */
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sector_t i_zsector;
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/* File zone write pointer position (sequential zones only) */
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loff_t i_wpoffset;
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/* File maximum size */
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loff_t i_max_size;
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/*
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* To serialise fully against both syscall and mmap based IO and
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* sequential file truncation, two locks are used. For serializing
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* zonefs_seq_file_truncate() against zonefs_iomap_begin(), that is,
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* file truncate operations against block mapping, i_truncate_mutex is
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* used. i_truncate_mutex also protects against concurrent accesses
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* and changes to the inode private data, and in particular changes to
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* a sequential file size on completion of direct IO writes.
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* Serialization of mmap read IOs with truncate and syscall IO
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* operations is done with i_mmap_sem in addition to i_truncate_mutex.
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* Only zonefs_seq_file_truncate() takes both lock (i_mmap_sem first,
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* i_truncate_mutex second).
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*/
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struct mutex i_truncate_mutex;
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struct rw_semaphore i_mmap_sem;
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};
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static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
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{
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return container_of(inode, struct zonefs_inode_info, i_vnode);
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}
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/*
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* On-disk super block (block 0).
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*/
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#define ZONEFS_LABEL_LEN 64
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#define ZONEFS_UUID_SIZE 16
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#define ZONEFS_SUPER_SIZE 4096
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struct zonefs_super {
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/* Magic number */
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__le32 s_magic;
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/* Checksum */
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__le32 s_crc;
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/* Volume label */
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char s_label[ZONEFS_LABEL_LEN];
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/* 128-bit uuid */
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__u8 s_uuid[ZONEFS_UUID_SIZE];
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/* Features */
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__le64 s_features;
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/* UID/GID to use for files */
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__le32 s_uid;
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__le32 s_gid;
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/* File permissions */
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__le32 s_perm;
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/* Padding to ZONEFS_SUPER_SIZE bytes */
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__u8 s_reserved[3988];
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} __packed;
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/*
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* Feature flags: specified in the s_features field of the on-disk super
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* block struct zonefs_super and in-memory in the s_feartures field of
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* struct zonefs_sb_info.
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*/
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enum zonefs_features {
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/*
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* Aggregate contiguous conventional zones into a single file.
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*/
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ZONEFS_F_AGGRCNV = 1ULL << 0,
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/*
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* Use super block specified UID for files instead of default 0.
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*/
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ZONEFS_F_UID = 1ULL << 1,
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/*
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* Use super block specified GID for files instead of default 0.
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*/
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ZONEFS_F_GID = 1ULL << 2,
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/*
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* Use super block specified file permissions instead of default 640.
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*/
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ZONEFS_F_PERM = 1ULL << 3,
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};
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#define ZONEFS_F_DEFINED_FEATURES \
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(ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
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/*
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* Mount options for zone write pointer error handling.
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*/
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#define ZONEFS_MNTOPT_ERRORS_RO (1 << 0) /* Make zone file readonly */
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#define ZONEFS_MNTOPT_ERRORS_ZRO (1 << 1) /* Make zone file offline */
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#define ZONEFS_MNTOPT_ERRORS_ZOL (1 << 2) /* Make zone file offline */
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#define ZONEFS_MNTOPT_ERRORS_REPAIR (1 << 3) /* Remount read-only */
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#define ZONEFS_MNTOPT_ERRORS_MASK \
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(ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \
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ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR)
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/*
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* In-memory Super block information.
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*/
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struct zonefs_sb_info {
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unsigned long s_mount_opts;
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spinlock_t s_lock;
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unsigned long long s_features;
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kuid_t s_uid;
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kgid_t s_gid;
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umode_t s_perm;
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uuid_t s_uuid;
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unsigned int s_zone_sectors_shift;
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unsigned int s_nr_files[ZONEFS_ZTYPE_MAX];
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loff_t s_blocks;
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loff_t s_used_blocks;
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};
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static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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#define zonefs_info(sb, format, args...) \
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pr_info("zonefs (%s): " format, sb->s_id, ## args)
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#define zonefs_err(sb, format, args...) \
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pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args)
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#define zonefs_warn(sb, format, args...) \
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pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
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#endif
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