1// SPDX-License-Identifier: GPL-2.0
2/*
3 *  linux/fs/sysv/inode.c
4 *
5 *  minix/inode.c
6 *  Copyright (C) 1991, 1992  Linus Torvalds
7 *
8 *  xenix/inode.c
9 *  Copyright (C) 1992  Doug Evans
10 *
11 *  coh/inode.c
12 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
13 *
14 *  sysv/inode.c
15 *  Copyright (C) 1993  Paul B. Monday
16 *
17 *  sysv/inode.c
18 *  Copyright (C) 1993  Bruno Haible
19 *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
20 *
21 *  This file contains code for allocating/freeing inodes and for read/writing
22 *  the superblock.
23 */
24
25#include <linux/highuid.h>
26#include <linux/slab.h>
27#include <linux/init.h>
28#include <linux/buffer_head.h>
29#include <linux/vfs.h>
30#include <linux/writeback.h>
31#include <linux/namei.h>
32#include <asm/byteorder.h>
33#include "sysv.h"
34
35static int sysv_sync_fs(struct super_block *sb, int wait)
36{
37	struct sysv_sb_info *sbi = SYSV_SB(sb);
38	u32 time = (u32)ktime_get_real_seconds(), old_time;
39
40	mutex_lock(&sbi->s_lock);
41
42	/*
43	 * If we are going to write out the super block,
44	 * then attach current time stamp.
45	 * But if the filesystem was marked clean, keep it clean.
46	 */
47	old_time = fs32_to_cpu(sbi, *sbi->s_sb_time);
48	if (sbi->s_type == FSTYPE_SYSV4) {
49		if (*sbi->s_sb_state == cpu_to_fs32(sbi, 0x7c269d38u - old_time))
50			*sbi->s_sb_state = cpu_to_fs32(sbi, 0x7c269d38u - time);
51		*sbi->s_sb_time = cpu_to_fs32(sbi, time);
52		mark_buffer_dirty(sbi->s_bh2);
53	}
54
55	mutex_unlock(&sbi->s_lock);
56
57	return 0;
58}
59
60static int sysv_remount(struct super_block *sb, int *flags, char *data)
61{
62	struct sysv_sb_info *sbi = SYSV_SB(sb);
63
64	sync_filesystem(sb);
65	if (sbi->s_forced_ro)
66		*flags |= SB_RDONLY;
67	return 0;
68}
69
70static void sysv_put_super(struct super_block *sb)
71{
72	struct sysv_sb_info *sbi = SYSV_SB(sb);
73
74	if (!sb_rdonly(sb)) {
75		/* XXX ext2 also updates the state here */
76		mark_buffer_dirty(sbi->s_bh1);
77		if (sbi->s_bh1 != sbi->s_bh2)
78			mark_buffer_dirty(sbi->s_bh2);
79	}
80
81	brelse(sbi->s_bh1);
82	if (sbi->s_bh1 != sbi->s_bh2)
83		brelse(sbi->s_bh2);
84
85	kfree(sbi);
86}
87
88static int sysv_statfs(struct dentry *dentry, struct kstatfs *buf)
89{
90	struct super_block *sb = dentry->d_sb;
91	struct sysv_sb_info *sbi = SYSV_SB(sb);
92	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
93
94	buf->f_type = sb->s_magic;
95	buf->f_bsize = sb->s_blocksize;
96	buf->f_blocks = sbi->s_ndatazones;
97	buf->f_bavail = buf->f_bfree = sysv_count_free_blocks(sb);
98	buf->f_files = sbi->s_ninodes;
99	buf->f_ffree = sysv_count_free_inodes(sb);
100	buf->f_namelen = SYSV_NAMELEN;
101	buf->f_fsid = u64_to_fsid(id);
102	return 0;
103}
104
105/*
106 * NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
107 */
108static inline void read3byte(struct sysv_sb_info *sbi,
109	unsigned char * from, unsigned char * to)
110{
111	if (sbi->s_bytesex == BYTESEX_PDP) {
112		to[0] = from[0];
113		to[1] = 0;
114		to[2] = from[1];
115		to[3] = from[2];
116	} else if (sbi->s_bytesex == BYTESEX_LE) {
117		to[0] = from[0];
118		to[1] = from[1];
119		to[2] = from[2];
120		to[3] = 0;
121	} else {
122		to[0] = 0;
123		to[1] = from[0];
124		to[2] = from[1];
125		to[3] = from[2];
126	}
127}
128
129static inline void write3byte(struct sysv_sb_info *sbi,
130	unsigned char * from, unsigned char * to)
131{
132	if (sbi->s_bytesex == BYTESEX_PDP) {
133		to[0] = from[0];
134		to[1] = from[2];
135		to[2] = from[3];
136	} else if (sbi->s_bytesex == BYTESEX_LE) {
137		to[0] = from[0];
138		to[1] = from[1];
139		to[2] = from[2];
140	} else {
141		to[0] = from[1];
142		to[1] = from[2];
143		to[2] = from[3];
144	}
145}
146
147static const struct inode_operations sysv_symlink_inode_operations = {
148	.get_link	= page_get_link,
149	.getattr	= sysv_getattr,
150};
151
152void sysv_set_inode(struct inode *inode, dev_t rdev)
153{
154	if (S_ISREG(inode->i_mode)) {
155		inode->i_op = &sysv_file_inode_operations;
156		inode->i_fop = &sysv_file_operations;
157		inode->i_mapping->a_ops = &sysv_aops;
158	} else if (S_ISDIR(inode->i_mode)) {
159		inode->i_op = &sysv_dir_inode_operations;
160		inode->i_fop = &sysv_dir_operations;
161		inode->i_mapping->a_ops = &sysv_aops;
162	} else if (S_ISLNK(inode->i_mode)) {
163		inode->i_op = &sysv_symlink_inode_operations;
164		inode_nohighmem(inode);
165		inode->i_mapping->a_ops = &sysv_aops;
166	} else
167		init_special_inode(inode, inode->i_mode, rdev);
168}
169
170struct inode *sysv_iget(struct super_block *sb, unsigned int ino)
171{
172	struct sysv_sb_info * sbi = SYSV_SB(sb);
173	struct buffer_head * bh;
174	struct sysv_inode * raw_inode;
175	struct sysv_inode_info * si;
176	struct inode *inode;
177	unsigned int block;
178
179	if (!ino || ino > sbi->s_ninodes) {
180		printk("Bad inode number on dev %s: %d is out of range\n",
181		       sb->s_id, ino);
182		return ERR_PTR(-EIO);
183	}
184
185	inode = iget_locked(sb, ino);
186	if (!inode)
187		return ERR_PTR(-ENOMEM);
188	if (!(inode->i_state & I_NEW))
189		return inode;
190
191	raw_inode = sysv_raw_inode(sb, ino, &bh);
192	if (!raw_inode) {
193		printk("Major problem: unable to read inode from dev %s\n",
194		       inode->i_sb->s_id);
195		goto bad_inode;
196	}
197	/* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
198	inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
199	i_uid_write(inode, (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid));
200	i_gid_write(inode, (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid));
201	set_nlink(inode, fs16_to_cpu(sbi, raw_inode->i_nlink));
202	inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
203	inode_set_atime(inode, fs32_to_cpu(sbi, raw_inode->i_atime), 0);
204	inode_set_mtime(inode, fs32_to_cpu(sbi, raw_inode->i_mtime), 0);
205	inode_set_ctime(inode, fs32_to_cpu(sbi, raw_inode->i_ctime), 0);
206	inode->i_blocks = 0;
207
208	si = SYSV_I(inode);
209	for (block = 0; block < 10+1+1+1; block++)
210		read3byte(sbi, &raw_inode->i_data[3*block],
211				(u8 *)&si->i_data[block]);
212	brelse(bh);
213	si->i_dir_start_lookup = 0;
214	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
215		sysv_set_inode(inode,
216			       old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
217	else
218		sysv_set_inode(inode, 0);
219	unlock_new_inode(inode);
220	return inode;
221
222bad_inode:
223	iget_failed(inode);
224	return ERR_PTR(-EIO);
225}
226
227static int __sysv_write_inode(struct inode *inode, int wait)
228{
229	struct super_block * sb = inode->i_sb;
230	struct sysv_sb_info * sbi = SYSV_SB(sb);
231	struct buffer_head * bh;
232	struct sysv_inode * raw_inode;
233	struct sysv_inode_info * si;
234	unsigned int ino, block;
235	int err = 0;
236
237	ino = inode->i_ino;
238	if (!ino || ino > sbi->s_ninodes) {
239		printk("Bad inode number on dev %s: %d is out of range\n",
240		       inode->i_sb->s_id, ino);
241		return -EIO;
242	}
243	raw_inode = sysv_raw_inode(sb, ino, &bh);
244	if (!raw_inode) {
245		printk("unable to read i-node block\n");
246		return -EIO;
247	}
248
249	raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
250	raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(i_uid_read(inode)));
251	raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(i_gid_read(inode)));
252	raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
253	raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
254	raw_inode->i_atime = cpu_to_fs32(sbi, inode_get_atime_sec(inode));
255	raw_inode->i_mtime = cpu_to_fs32(sbi, inode_get_mtime_sec(inode));
256	raw_inode->i_ctime = cpu_to_fs32(sbi, inode_get_ctime_sec(inode));
257
258	si = SYSV_I(inode);
259	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
260		si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
261	for (block = 0; block < 10+1+1+1; block++)
262		write3byte(sbi, (u8 *)&si->i_data[block],
263			&raw_inode->i_data[3*block]);
264	mark_buffer_dirty(bh);
265	if (wait) {
266                sync_dirty_buffer(bh);
267                if (buffer_req(bh) && !buffer_uptodate(bh)) {
268                        printk ("IO error syncing sysv inode [%s:%08x]\n",
269                                sb->s_id, ino);
270                        err = -EIO;
271                }
272        }
273	brelse(bh);
274	return err;
275}
276
277int sysv_write_inode(struct inode *inode, struct writeback_control *wbc)
278{
279	return __sysv_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
280}
281
282int sysv_sync_inode(struct inode *inode)
283{
284	return __sysv_write_inode(inode, 1);
285}
286
287static void sysv_evict_inode(struct inode *inode)
288{
289	truncate_inode_pages_final(&inode->i_data);
290	if (!inode->i_nlink) {
291		inode->i_size = 0;
292		sysv_truncate(inode);
293	}
294	invalidate_inode_buffers(inode);
295	clear_inode(inode);
296	if (!inode->i_nlink)
297		sysv_free_inode(inode);
298}
299
300static struct kmem_cache *sysv_inode_cachep;
301
302static struct inode *sysv_alloc_inode(struct super_block *sb)
303{
304	struct sysv_inode_info *si;
305
306	si = alloc_inode_sb(sb, sysv_inode_cachep, GFP_KERNEL);
307	if (!si)
308		return NULL;
309	return &si->vfs_inode;
310}
311
312static void sysv_free_in_core_inode(struct inode *inode)
313{
314	kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
315}
316
317static void init_once(void *p)
318{
319	struct sysv_inode_info *si = (struct sysv_inode_info *)p;
320
321	inode_init_once(&si->vfs_inode);
322}
323
324const struct super_operations sysv_sops = {
325	.alloc_inode	= sysv_alloc_inode,
326	.free_inode	= sysv_free_in_core_inode,
327	.write_inode	= sysv_write_inode,
328	.evict_inode	= sysv_evict_inode,
329	.put_super	= sysv_put_super,
330	.sync_fs	= sysv_sync_fs,
331	.remount_fs	= sysv_remount,
332	.statfs		= sysv_statfs,
333};
334
335int __init sysv_init_icache(void)
336{
337	sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
338			sizeof(struct sysv_inode_info), 0,
339			SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
340			init_once);
341	if (!sysv_inode_cachep)
342		return -ENOMEM;
343	return 0;
344}
345
346void sysv_destroy_icache(void)
347{
348	/*
349	 * Make sure all delayed rcu free inodes are flushed before we
350	 * destroy cache.
351	 */
352	rcu_barrier();
353	kmem_cache_destroy(sysv_inode_cachep);
354}
355