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linux-next/fs/hfs/hfs_fs.h
Arnd Bergmann 4ddfc3dc60 hfs/hfsplus: use 64-bit inode timestamps 
The interpretation of on-disk timestamps in HFS and HFS+ differs
between 32-bit and 64-bit kernels at the moment. Use 64-bit timestamps
consistently so apply the current 64-bit behavior everyhere.

According to the official documentation for HFS+ [1], inode timestamps
are supposed to cover the time range from 1904 to 2040 as originally
used in classic MacOS.

The traditional Linux usage is to convert the timestamps into an unsigned
32-bit number based on the Unix epoch and from there to a time_t. On
32-bit systems, that wraps the time from 2038 to 1902, so the last
two years of the valid time range become garbled. On 64-bit systems,
all times before 1970 get turned into timestamps between 2038 and 2106,
which is more convenient but also different from the documented behavior.

Looking at the Darwin sources [2], it seems that MacOS is inconsistent in
yet another way: all timestamps are wrapped around to a 32-bit unsigned
number when written to the disk, but when read back, all numeric values
lower than 2082844800U are assumed to be invalid, so we cannot represent
the times before 1970 or the times after 2040.

While all implementations seem to agree on the interpretation of values
between 1970 and 2038, they often differ on the exact range they support
when reading back values outside of the common range:

MacOS (traditional):		1904-2040
Apple Documentation:		1904-2040
MacOS X source comments:	1970-2040
MacOS X source code:		1970-2038
32-bit Linux:			1902-2038
64-bit Linux:			1970-2106
hfsfuse:			1970-2040
hfsutils (32 bit, old libc)	1902-2038
hfsutils (32 bit, new libc)	1970-2106
hfsutils (64 bit)		1904-2040
hfsplus-utils			1904-2040
hfsexplorer			1904-2040
7-zip				1904-2040

Out of the above, the range from 1970 to 2106 seems to be the most useful,
as it allows using HFS and HFS+ beyond year 2038, and this matches the
behavior that most users would see today on Linux, as few people run
32-bit kernels any more.

Link: [1] https://developer.apple.com/library/archive/technotes/tn/tn1150.html
Link: [2] https://opensource.apple.com/source/hfs/hfs-407.30.1/core/MacOSStubs.c.auto.html
Link: https://lore.kernel.org/lkml/20180711224625.airwna6gzyatoowe@eaf/
Suggested-by: "Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: revert back to 1970-2106 time range
    fix bugs found in review
    merge both patches into one
    drop cc:stable tag
v2: treat pre-1970 dates as invalid following MacOS X behavior,
    reword and expand changelog text
2019-12-18 18:07:32 +01:00

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/*
* linux/fs/hfs/hfs_fs.h
*
* Copyright (C) 1995-1997 Paul H. Hargrove
* (C) 2003 Ardis Technologies <roman@ardistech.com>
* This file may be distributed under the terms of the GNU General Public License.
*/
#ifndef _LINUX_HFS_FS_H
#define _LINUX_HFS_FS_H
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/workqueue.h>
#include <asm/byteorder.h>
#include <linux/uaccess.h>
#include "hfs.h"
#define DBG_BNODE_REFS 0x00000001
#define DBG_BNODE_MOD 0x00000002
#define DBG_CAT_MOD 0x00000004
#define DBG_INODE 0x00000008
#define DBG_SUPER 0x00000010
#define DBG_EXTENT 0x00000020
#define DBG_BITMAP 0x00000040
//#define DBG_MASK (DBG_EXTENT|DBG_INODE|DBG_BNODE_MOD|DBG_CAT_MOD|DBG_BITMAP)
//#define DBG_MASK (DBG_BNODE_MOD|DBG_CAT_MOD|DBG_INODE)
//#define DBG_MASK (DBG_CAT_MOD|DBG_BNODE_REFS|DBG_INODE|DBG_EXTENT)
#define DBG_MASK (0)
#define hfs_dbg(flg, fmt, ...) \
do { \
if (DBG_##flg & DBG_MASK) \
printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); \
} while (0)
#define hfs_dbg_cont(flg, fmt, ...) \
do { \
if (DBG_##flg & DBG_MASK) \
pr_cont(fmt, ##__VA_ARGS__); \
} while (0)
/*
* struct hfs_inode_info
*
* The HFS-specific part of a Linux (struct inode)
*/
struct hfs_inode_info {
atomic_t opencnt;
unsigned int flags;
/* to deal with localtime ugliness */
int tz_secondswest;
struct hfs_cat_key cat_key;
struct list_head open_dir_list;
spinlock_t open_dir_lock;
struct inode *rsrc_inode;
struct mutex extents_lock;
u16 alloc_blocks, clump_blocks;
sector_t fs_blocks;
/* Allocation extents from catlog record or volume header */
hfs_extent_rec first_extents;
u16 first_blocks;
hfs_extent_rec cached_extents;
u16 cached_start, cached_blocks;
loff_t phys_size;
struct inode vfs_inode;
};
#define HFS_FLG_RSRC 0x0001
#define HFS_FLG_EXT_DIRTY 0x0002
#define HFS_FLG_EXT_NEW 0x0004
#define HFS_IS_RSRC(inode) (HFS_I(inode)->flags & HFS_FLG_RSRC)
/*
* struct hfs_sb_info
*
* The HFS-specific part of a Linux (struct super_block)
*/
struct hfs_sb_info {
struct buffer_head *mdb_bh; /* The hfs_buffer
holding the real
superblock (aka VIB
or MDB) */
struct hfs_mdb *mdb;
struct buffer_head *alt_mdb_bh; /* The hfs_buffer holding
the alternate superblock */
struct hfs_mdb *alt_mdb;
__be32 *bitmap; /* The page holding the
allocation bitmap */
struct hfs_btree *ext_tree; /* Information about
the extents b-tree */
struct hfs_btree *cat_tree; /* Information about
the catalog b-tree */
u32 file_count; /* The number of
regular files in
the filesystem */
u32 folder_count; /* The number of
directories in the
filesystem */
u32 next_id; /* The next available
file id number */
u32 clumpablks; /* The number of allocation
blocks to try to add when
extending a file */
u32 fs_start; /* The first 512-byte
block represented
in the bitmap */
u32 part_start;
u16 root_files; /* The number of
regular
(non-directory)
files in the root
directory */
u16 root_dirs; /* The number of
directories in the
root directory */
u16 fs_ablocks; /* The number of
allocation blocks
in the filesystem */
u16 free_ablocks; /* the number of unused
allocation blocks
in the filesystem */
u32 alloc_blksz; /* The size of an
"allocation block" */
int s_quiet; /* Silent failure when
changing owner or mode? */
__be32 s_type; /* Type for new files */
__be32 s_creator; /* Creator for new files */
umode_t s_file_umask; /* The umask applied to the
permissions on all files */
umode_t s_dir_umask; /* The umask applied to the
permissions on all dirs */
kuid_t s_uid; /* The uid of all files */
kgid_t s_gid; /* The gid of all files */
int session, part;
struct nls_table *nls_io, *nls_disk;
struct mutex bitmap_lock;
unsigned long flags;
u16 blockoffset;
int fs_div;
struct super_block *sb;
int work_queued; /* non-zero delayed work is queued */
struct delayed_work mdb_work; /* MDB flush delayed work */
spinlock_t work_lock; /* protects mdb_work and work_queued */
};
#define HFS_FLG_BITMAP_DIRTY 0
#define HFS_FLG_MDB_DIRTY 1
#define HFS_FLG_ALT_MDB_DIRTY 2
/* bitmap.c */
extern u32 hfs_vbm_search_free(struct super_block *, u32, u32 *);
extern int hfs_clear_vbm_bits(struct super_block *, u16, u16);
/* catalog.c */
extern int hfs_cat_keycmp(const btree_key *, const btree_key *);
struct hfs_find_data;
extern int hfs_cat_find_brec(struct super_block *, u32, struct hfs_find_data *);
extern int hfs_cat_create(u32, struct inode *, const struct qstr *, struct inode *);
extern int hfs_cat_delete(u32, struct inode *, const struct qstr *);
extern int hfs_cat_move(u32, struct inode *, const struct qstr *,
struct inode *, const struct qstr *);
extern void hfs_cat_build_key(struct super_block *, btree_key *, u32, const struct qstr *);
/* dir.c */
extern const struct file_operations hfs_dir_operations;
extern const struct inode_operations hfs_dir_inode_operations;
/* extent.c */
extern int hfs_ext_keycmp(const btree_key *, const btree_key *);
extern int hfs_free_fork(struct super_block *, struct hfs_cat_file *, int);
extern int hfs_ext_write_extent(struct inode *);
extern int hfs_extend_file(struct inode *);
extern void hfs_file_truncate(struct inode *);
extern int hfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
/* inode.c */
extern const struct address_space_operations hfs_aops;
extern const struct address_space_operations hfs_btree_aops;
extern struct inode *hfs_new_inode(struct inode *, const struct qstr *, umode_t);
extern void hfs_inode_write_fork(struct inode *, struct hfs_extent *, __be32 *, __be32 *);
extern int hfs_write_inode(struct inode *, struct writeback_control *);
extern int hfs_inode_setattr(struct dentry *, struct iattr *);
extern void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
__be32 log_size, __be32 phys_size, u32 clump_size);
extern struct inode *hfs_iget(struct super_block *, struct hfs_cat_key *, hfs_cat_rec *);
extern void hfs_evict_inode(struct inode *);
extern void hfs_delete_inode(struct inode *);
/* attr.c */
extern const struct xattr_handler *hfs_xattr_handlers[];
/* mdb.c */
extern int hfs_mdb_get(struct super_block *);
extern void hfs_mdb_commit(struct super_block *);
extern void hfs_mdb_close(struct super_block *);
extern void hfs_mdb_put(struct super_block *);
/* part_tbl.c */
extern int hfs_part_find(struct super_block *, sector_t *, sector_t *);
/* string.c */
extern const struct dentry_operations hfs_dentry_operations;
extern int hfs_hash_dentry(const struct dentry *, struct qstr *);
extern int hfs_strcmp(const unsigned char *, unsigned int,
const unsigned char *, unsigned int);
extern int hfs_compare_dentry(const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name);
/* trans.c */
extern void hfs_asc2mac(struct super_block *, struct hfs_name *, const struct qstr *);
extern int hfs_mac2asc(struct super_block *, char *, const struct hfs_name *);
/* super.c */
extern void hfs_mark_mdb_dirty(struct super_block *sb);
/*
* There are two time systems. Both are based on seconds since
* a particular time/date.
* Unix: signed little-endian since 00:00 GMT, Jan. 1, 1970
* mac: unsigned big-endian since 00:00 GMT, Jan. 1, 1904
*
* HFS implementations are highly inconsistent, this one matches the
* traditional behavior of 64-bit Linux, giving the most useful
* time range between 1970 and 2106, by treating any on-disk timestamp
* under HFS_UTC_OFFSET (Jan 1 1970) as a time between 2040 and 2106.
*/
#define HFS_UTC_OFFSET 2082844800U
static inline time64_t __hfs_m_to_utime(__be32 mt)
{
time64_t ut = (u32)(be32_to_cpu(mt) - HFS_UTC_OFFSET);
return ut + sys_tz.tz_minuteswest * 60;
}
static inline __be32 __hfs_u_to_mtime(time64_t ut)
{
ut -= sys_tz.tz_minuteswest * 60;
return cpu_to_be32(lower_32_bits(ut) + HFS_UTC_OFFSET);
}
#define HFS_I(inode) (container_of(inode, struct hfs_inode_info, vfs_inode))
#define HFS_SB(sb) ((struct hfs_sb_info *)(sb)->s_fs_info)
#define hfs_m_to_utime(time) (struct timespec64){ .tv_sec = __hfs_m_to_utime(time) }
#define hfs_u_to_mtime(time) __hfs_u_to_mtime((time).tv_sec)
#define hfs_mtime() __hfs_u_to_mtime(ktime_get_real_seconds())
static inline const char *hfs_mdb_name(struct super_block *sb)
{
return sb->s_id;
}
static inline void hfs_bitmap_dirty(struct super_block *sb)
{
set_bit(HFS_FLG_BITMAP_DIRTY, &HFS_SB(sb)->flags);
hfs_mark_mdb_dirty(sb);
}
#define sb_bread512(sb, sec, data) ({ \
struct buffer_head *__bh; \
sector_t __block; \
loff_t __start; \
int __offset; \
\
__start = (loff_t)(sec) << HFS_SECTOR_SIZE_BITS;\
__block = __start >> (sb)->s_blocksize_bits; \
__offset = __start & ((sb)->s_blocksize - 1); \
__bh = sb_bread((sb), __block); \
if (likely(__bh != NULL)) \
data = (void *)(__bh->b_data + __offset);\
else \
data = NULL; \
__bh; \
})
#endif
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