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linux/fs/sysv/super.c
Deepa Dinamani 452c277941 fs: sysv: Initialize filesystem timestamp ranges 
Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: hch@infradead.org
2019-08-30 07:27:18 -07:00

595 lines
15 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/sysv/inode.c
*
* minix/inode.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* xenix/inode.c
* Copyright (C) 1992 Doug Evans
*
* coh/inode.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/inode.c
* Copyright (C) 1993 Paul B. Monday
*
* sysv/inode.c
* Copyright (C) 1993 Bruno Haible
* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
*
* This file contains code for read/parsing the superblock.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include "sysv.h"
/*
* The following functions try to recognize specific filesystems.
*
* We recognize:
* - Xenix FS by its magic number.
* - SystemV FS by its magic number.
* - Coherent FS by its funny fname/fpack field.
* - SCO AFS by s_nfree == 0xffff
* - V7 FS has no distinguishing features.
*
* We discriminate among SystemV4 and SystemV2 FS by the assumption that
* the time stamp is not < 01-01-1980.
*/
enum {
JAN_1_1980 = (10*365 + 2) * 24 * 60 * 60
};
static void detected_xenix(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct buffer_head *bh1 = sbi->s_bh1;
struct buffer_head *bh2 = sbi->s_bh2;
struct xenix_super_block * sbd1;
struct xenix_super_block * sbd2;
if (bh1 != bh2)
sbd1 = sbd2 = (struct xenix_super_block *) bh1->b_data;
else {
/* block size = 512, so bh1 != bh2 */
sbd1 = (struct xenix_super_block *) bh1->b_data;
sbd2 = (struct xenix_super_block *) (bh2->b_data - 512);
}
*max_links = XENIX_LINK_MAX;
sbi->s_fic_size = XENIX_NICINOD;
sbi->s_flc_size = XENIX_NICFREE;
sbi->s_sbd1 = (char *)sbd1;
sbi->s_sbd2 = (char *)sbd2;
sbi->s_sb_fic_count = &sbd1->s_ninode;
sbi->s_sb_fic_inodes = &sbd1->s_inode[0];
sbi->s_sb_total_free_inodes = &sbd2->s_tinode;
sbi->s_bcache_count = &sbd1->s_nfree;
sbi->s_bcache = &sbd1->s_free[0];
sbi->s_free_blocks = &sbd2->s_tfree;
sbi->s_sb_time = &sbd2->s_time;
sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd1->s_isize);
sbi->s_nzones = fs32_to_cpu(sbi, sbd1->s_fsize);
}
static void detected_sysv4(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct sysv4_super_block * sbd;
struct buffer_head *bh1 = sbi->s_bh1;
struct buffer_head *bh2 = sbi->s_bh2;
if (bh1 == bh2)
sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2);
else
sbd = (struct sysv4_super_block *) bh2->b_data;
*max_links = SYSV_LINK_MAX;
sbi->s_fic_size = SYSV_NICINOD;
sbi->s_flc_size = SYSV_NICFREE;
sbi->s_sbd1 = (char *)sbd;
sbi->s_sbd2 = (char *)sbd;
sbi->s_sb_fic_count = &sbd->s_ninode;
sbi->s_sb_fic_inodes = &sbd->s_inode[0];
sbi->s_sb_total_free_inodes = &sbd->s_tinode;
sbi->s_bcache_count = &sbd->s_nfree;
sbi->s_bcache = &sbd->s_free[0];
sbi->s_free_blocks = &sbd->s_tfree;
sbi->s_sb_time = &sbd->s_time;
sbi->s_sb_state = &sbd->s_state;
sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static void detected_sysv2(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct sysv2_super_block *sbd;
struct buffer_head *bh1 = sbi->s_bh1;
struct buffer_head *bh2 = sbi->s_bh2;
if (bh1 == bh2)
sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2);
else
sbd = (struct sysv2_super_block *) bh2->b_data;
*max_links = SYSV_LINK_MAX;
sbi->s_fic_size = SYSV_NICINOD;
sbi->s_flc_size = SYSV_NICFREE;
sbi->s_sbd1 = (char *)sbd;
sbi->s_sbd2 = (char *)sbd;
sbi->s_sb_fic_count = &sbd->s_ninode;
sbi->s_sb_fic_inodes = &sbd->s_inode[0];
sbi->s_sb_total_free_inodes = &sbd->s_tinode;
sbi->s_bcache_count = &sbd->s_nfree;
sbi->s_bcache = &sbd->s_free[0];
sbi->s_free_blocks = &sbd->s_tfree;
sbi->s_sb_time = &sbd->s_time;
sbi->s_sb_state = &sbd->s_state;
sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static void detected_coherent(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct coh_super_block * sbd;
struct buffer_head *bh1 = sbi->s_bh1;
sbd = (struct coh_super_block *) bh1->b_data;
*max_links = COH_LINK_MAX;
sbi->s_fic_size = COH_NICINOD;
sbi->s_flc_size = COH_NICFREE;
sbi->s_sbd1 = (char *)sbd;
sbi->s_sbd2 = (char *)sbd;
sbi->s_sb_fic_count = &sbd->s_ninode;
sbi->s_sb_fic_inodes = &sbd->s_inode[0];
sbi->s_sb_total_free_inodes = &sbd->s_tinode;
sbi->s_bcache_count = &sbd->s_nfree;
sbi->s_bcache = &sbd->s_free[0];
sbi->s_free_blocks = &sbd->s_tfree;
sbi->s_sb_time = &sbd->s_time;
sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static void detected_v7(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct buffer_head *bh2 = sbi->s_bh2;
struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data;
*max_links = V7_LINK_MAX;
sbi->s_fic_size = V7_NICINOD;
sbi->s_flc_size = V7_NICFREE;
sbi->s_sbd1 = (char *)sbd;
sbi->s_sbd2 = (char *)sbd;
sbi->s_sb_fic_count = &sbd->s_ninode;
sbi->s_sb_fic_inodes = &sbd->s_inode[0];
sbi->s_sb_total_free_inodes = &sbd->s_tinode;
sbi->s_bcache_count = &sbd->s_nfree;
sbi->s_bcache = &sbd->s_free[0];
sbi->s_free_blocks = &sbd->s_tfree;
sbi->s_sb_time = &sbd->s_time;
sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static int detect_xenix(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
struct xenix_super_block *sbd = (struct xenix_super_block *)bh->b_data;
if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0x2b5544))
sbi->s_bytesex = BYTESEX_LE;
else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0x2b5544))
sbi->s_bytesex = BYTESEX_BE;
else
return 0;
switch (fs32_to_cpu(sbi, sbd->s_type)) {
case 1:
sbi->s_type = FSTYPE_XENIX;
return 1;
case 2:
sbi->s_type = FSTYPE_XENIX;
return 2;
default:
return 0;
}
}
static int detect_sysv(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
struct super_block *sb = sbi->s_sb;
/* All relevant fields are at the same offsets in R2 and R4 */
struct sysv4_super_block * sbd;
u32 type;
sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2);
if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0xfd187e20))
sbi->s_bytesex = BYTESEX_LE;
else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0xfd187e20))
sbi->s_bytesex = BYTESEX_BE;
else
return 0;
type = fs32_to_cpu(sbi, sbd->s_type);
if (fs16_to_cpu(sbi, sbd->s_nfree) == 0xffff) {
sbi->s_type = FSTYPE_AFS;
sbi->s_forced_ro = 1;
if (!sb_rdonly(sb)) {
printk("SysV FS: SCO EAFS on %s detected, "
"forcing read-only mode.\n",
sb->s_id);
}
return type;
}
if (fs32_to_cpu(sbi, sbd->s_time) < JAN_1_1980) {
/* this is likely to happen on SystemV2 FS */
if (type > 3 || type < 1)
return 0;
sbi->s_type = FSTYPE_SYSV2;
return type;
}
if ((type > 3 || type < 1) && (type > 0x30 || type < 0x10))
return 0;
/* On Interactive Unix (ISC) Version 4.0/3.x s_type field = 0x10,
0x20 or 0x30 indicates that symbolic links and the 14-character
filename limit is gone. Due to lack of information about this
feature read-only mode seems to be a reasonable approach... -KGB */
if (type >= 0x10) {
printk("SysV FS: can't handle long file names on %s, "
"forcing read-only mode.\n", sb->s_id);
sbi->s_forced_ro = 1;
}
sbi->s_type = FSTYPE_SYSV4;
return type >= 0x10 ? type >> 4 : type;
}
static int detect_coherent(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
struct coh_super_block * sbd;
sbd = (struct coh_super_block *) (bh->b_data + BLOCK_SIZE/2);
if ((memcmp(sbd->s_fname,"noname",6) && memcmp(sbd->s_fname,"xxxxx ",6))
|| (memcmp(sbd->s_fpack,"nopack",6) && memcmp(sbd->s_fpack,"xxxxx\n",6)))
return 0;
sbi->s_bytesex = BYTESEX_PDP;
sbi->s_type = FSTYPE_COH;
return 1;
}
static int detect_sysv_odd(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
int size = detect_sysv(sbi, bh);
return size>2 ? 0 : size;
}
static struct {
int block;
int (*test)(struct sysv_sb_info *, struct buffer_head *);
} flavours[] = {
{1, detect_xenix},
{0, detect_sysv},
{0, detect_coherent},
{9, detect_sysv_odd},
{15,detect_sysv_odd},
{18,detect_sysv},
};
static char *flavour_names[] = {
[FSTYPE_XENIX] = "Xenix",
[FSTYPE_SYSV4] = "SystemV",
[FSTYPE_SYSV2] = "SystemV Release 2",
[FSTYPE_COH] = "Coherent",
[FSTYPE_V7] = "V7",
[FSTYPE_AFS] = "AFS",
};
static void (*flavour_setup[])(struct sysv_sb_info *, unsigned *) = {
[FSTYPE_XENIX] = detected_xenix,
[FSTYPE_SYSV4] = detected_sysv4,
[FSTYPE_SYSV2] = detected_sysv2,
[FSTYPE_COH] = detected_coherent,
[FSTYPE_V7] = detected_v7,
[FSTYPE_AFS] = detected_sysv4,
};
static int complete_read_super(struct super_block *sb, int silent, int size)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct inode *root_inode;
char *found = flavour_names[sbi->s_type];
u_char n_bits = size+8;
int bsize = 1 << n_bits;
int bsize_4 = bsize >> 2;
sbi->s_firstinodezone = 2;
flavour_setup[sbi->s_type](sbi, &sb->s_max_links);
sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone;
sbi->s_inodes_per_block = bsize >> 6;
sbi->s_inodes_per_block_1 = (bsize >> 6)-1;
sbi->s_inodes_per_block_bits = n_bits-6;
sbi->s_ind_per_block = bsize_4;
sbi->s_ind_per_block_2 = bsize_4*bsize_4;
sbi->s_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4));
sbi->s_ind_per_block_bits = n_bits-2;
sbi->s_ninodes = (sbi->s_firstdatazone - sbi->s_firstinodezone)
<< sbi->s_inodes_per_block_bits;
if (!silent)
printk("VFS: Found a %s FS (block size = %ld) on device %s\n",
found, sb->s_blocksize, sb->s_id);
sb->s_magic = SYSV_MAGIC_BASE + sbi->s_type;
/* set up enough so that it can read an inode */
sb->s_op = &sysv_sops;
if (sbi->s_forced_ro)
sb->s_flags |= SB_RDONLY;
root_inode = sysv_iget(sb, SYSV_ROOT_INO);
if (IS_ERR(root_inode)) {
printk("SysV FS: get root inode failed\n");
return 0;
}
sb->s_root = d_make_root(root_inode);
if (!sb->s_root) {
printk("SysV FS: get root dentry failed\n");
return 0;
}
return 1;
}
static int sysv_fill_super(struct super_block *sb, void *data, int silent)
{
struct buffer_head *bh1, *bh = NULL;
struct sysv_sb_info *sbi;
unsigned long blocknr;
int size = 0, i;
BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block));
BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block));
BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block));
BUILD_BUG_ON(500 != sizeof (struct coh_super_block));
BUILD_BUG_ON(64 != sizeof (struct sysv_inode));
sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sbi->s_sb = sb;
sbi->s_block_base = 0;
mutex_init(&sbi->s_lock);
sb->s_fs_info = sbi;
sb->s_time_min = 0;
sb->s_time_max = U32_MAX;
sb_set_blocksize(sb, BLOCK_SIZE);
for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) {
brelse(bh);
bh = sb_bread(sb, flavours[i].block);
if (!bh)
continue;
size = flavours[i].test(SYSV_SB(sb), bh);
}
if (!size)
goto Eunknown;
switch (size) {
case 1:
blocknr = bh->b_blocknr << 1;
brelse(bh);
sb_set_blocksize(sb, 512);
bh1 = sb_bread(sb, blocknr);
bh = sb_bread(sb, blocknr + 1);
break;
case 2:
bh1 = bh;
break;
case 3:
blocknr = bh->b_blocknr >> 1;
brelse(bh);
sb_set_blocksize(sb, 2048);
bh1 = bh = sb_bread(sb, blocknr);
break;
default:
goto Ebadsize;
}
if (bh && bh1) {
sbi->s_bh1 = bh1;
sbi->s_bh2 = bh;
if (complete_read_super(sb, silent, size))
return 0;
}
brelse(bh1);
brelse(bh);
sb_set_blocksize(sb, BLOCK_SIZE);
printk("oldfs: cannot read superblock\n");
failed:
kfree(sbi);
return -EINVAL;
Eunknown:
brelse(bh);
if (!silent)
printk("VFS: unable to find oldfs superblock on device %s\n",
sb->s_id);
goto failed;
Ebadsize:
brelse(bh);
if (!silent)
printk("VFS: oldfs: unsupported block size (%dKb)\n",
1<<(size-2));
goto failed;
}
static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh)
{
struct v7_super_block *v7sb;
struct sysv_inode *v7i;
struct buffer_head *bh2;
struct sysv_sb_info *sbi;
sbi = sb->s_fs_info;
/* plausibility check on superblock */
v7sb = (struct v7_super_block *) bh->b_data;
if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
return 0;
/* plausibility check on root inode: it is a directory,
with a nonzero size that is a multiple of 16 */
bh2 = sb_bread(sb, 2);
if (bh2 == NULL)
return 0;
v7i = (struct sysv_inode *)(bh2->b_data + 64);
if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
(fs32_to_cpu(sbi, v7i->i_size) == 0) ||
(fs32_to_cpu(sbi, v7i->i_size) & 017) ||
(fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
sizeof(struct sysv_dir_entry))) {
brelse(bh2);
return 0;
}
brelse(bh2);
return 1;
}
static int v7_fill_super(struct super_block *sb, void *data, int silent)
{
struct sysv_sb_info *sbi;
struct buffer_head *bh;
if (440 != sizeof (struct v7_super_block))
panic("V7 FS: bad super-block size");
if (64 != sizeof (struct sysv_inode))
panic("sysv fs: bad i-node size");
sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sbi->s_sb = sb;
sbi->s_block_base = 0;
sbi->s_type = FSTYPE_V7;
mutex_init(&sbi->s_lock);
sb->s_fs_info = sbi;
sb->s_time_min = 0;
sb->s_time_max = U32_MAX;
sb_set_blocksize(sb, 512);
if ((bh = sb_bread(sb, 1)) == NULL) {
if (!silent)
printk("VFS: unable to read V7 FS superblock on "
"device %s.\n", sb->s_id);
goto failed;
}
/* Try PDP-11 UNIX */
sbi->s_bytesex = BYTESEX_PDP;
if (v7_sanity_check(sb, bh))
goto detected;
/* Try PC/IX, v7/x86 */
sbi->s_bytesex = BYTESEX_LE;
if (v7_sanity_check(sb, bh))
goto detected;
goto failed;
detected:
sbi->s_bh1 = bh;
sbi->s_bh2 = bh;
if (complete_read_super(sb, silent, 1))
return 0;
failed:
printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",
sb->s_id);
brelse(bh);
kfree(sbi);
return -EINVAL;
}
/* Every kernel module contains stuff like this. */
static struct dentry *sysv_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, sysv_fill_super);
}
static struct dentry *v7_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, v7_fill_super);
}
static struct file_system_type sysv_fs_type = {
.owner = THIS_MODULE,
.name = "sysv",
.mount = sysv_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("sysv");
static struct file_system_type v7_fs_type = {
.owner = THIS_MODULE,
.name = "v7",
.mount = v7_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("v7");
MODULE_ALIAS("v7");
static int __init init_sysv_fs(void)
{
int error;
error = sysv_init_icache();
if (error)
goto out;
error = register_filesystem(&sysv_fs_type);
if (error)
goto destroy_icache;
error = register_filesystem(&v7_fs_type);
if (error)
goto unregister;
return 0;
unregister:
unregister_filesystem(&sysv_fs_type);
destroy_icache:
sysv_destroy_icache();
out:
return error;
}
static void __exit exit_sysv_fs(void)
{
unregister_filesystem(&sysv_fs_type);
unregister_filesystem(&v7_fs_type);
sysv_destroy_icache();
}
module_init(init_sysv_fs)
module_exit(exit_sysv_fs)
MODULE_LICENSE("GPL");
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