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 
sysv_sync_fs(struct super_block * sb,int wait)35 static 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 
sysv_remount(struct super_block * sb,int * flags,char * data)60 static 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 
sysv_put_super(struct super_block * sb)70 static 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 
sysv_statfs(struct dentry * dentry,struct kstatfs * buf)88 static 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.val[0] = (u32)id;
102 	buf->f_fsid.val[1] = (u32)(id >> 32);
103 	return 0;
104 }
105 
106 /*
107  * NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
108  */
read3byte(struct sysv_sb_info * sbi,unsigned char * from,unsigned char * to)109 static inline void read3byte(struct sysv_sb_info *sbi,
110 	unsigned char * from, unsigned char * to)
111 {
112 	if (sbi->s_bytesex == BYTESEX_PDP) {
113 		to[0] = from[0];
114 		to[1] = 0;
115 		to[2] = from[1];
116 		to[3] = from[2];
117 	} else if (sbi->s_bytesex == BYTESEX_LE) {
118 		to[0] = from[0];
119 		to[1] = from[1];
120 		to[2] = from[2];
121 		to[3] = 0;
122 	} else {
123 		to[0] = 0;
124 		to[1] = from[0];
125 		to[2] = from[1];
126 		to[3] = from[2];
127 	}
128 }
129 
write3byte(struct sysv_sb_info * sbi,unsigned char * from,unsigned char * to)130 static inline void write3byte(struct sysv_sb_info *sbi,
131 	unsigned char * from, unsigned char * to)
132 {
133 	if (sbi->s_bytesex == BYTESEX_PDP) {
134 		to[0] = from[0];
135 		to[1] = from[2];
136 		to[2] = from[3];
137 	} else if (sbi->s_bytesex == BYTESEX_LE) {
138 		to[0] = from[0];
139 		to[1] = from[1];
140 		to[2] = from[2];
141 	} else {
142 		to[0] = from[1];
143 		to[1] = from[2];
144 		to[2] = from[3];
145 	}
146 }
147 
148 static const struct inode_operations sysv_symlink_inode_operations = {
149 	.get_link	= page_get_link,
150 	.getattr	= sysv_getattr,
151 };
152 
sysv_set_inode(struct inode * inode,dev_t rdev)153 void sysv_set_inode(struct inode *inode, dev_t rdev)
154 {
155 	if (S_ISREG(inode->i_mode)) {
156 		inode->i_op = &sysv_file_inode_operations;
157 		inode->i_fop = &sysv_file_operations;
158 		inode->i_mapping->a_ops = &sysv_aops;
159 	} else if (S_ISDIR(inode->i_mode)) {
160 		inode->i_op = &sysv_dir_inode_operations;
161 		inode->i_fop = &sysv_dir_operations;
162 		inode->i_mapping->a_ops = &sysv_aops;
163 	} else if (S_ISLNK(inode->i_mode)) {
164 		inode->i_op = &sysv_symlink_inode_operations;
165 		inode_nohighmem(inode);
166 		inode->i_mapping->a_ops = &sysv_aops;
167 	} else
168 		init_special_inode(inode, inode->i_mode, rdev);
169 }
170 
sysv_iget(struct super_block * sb,unsigned int ino)171 struct inode *sysv_iget(struct super_block *sb, unsigned int ino)
172 {
173 	struct sysv_sb_info * sbi = SYSV_SB(sb);
174 	struct buffer_head * bh;
175 	struct sysv_inode * raw_inode;
176 	struct sysv_inode_info * si;
177 	struct inode *inode;
178 	unsigned int block;
179 
180 	if (!ino || ino > sbi->s_ninodes) {
181 		printk("Bad inode number on dev %s: %d is out of range\n",
182 		       sb->s_id, ino);
183 		return ERR_PTR(-EIO);
184 	}
185 
186 	inode = iget_locked(sb, ino);
187 	if (!inode)
188 		return ERR_PTR(-ENOMEM);
189 	if (!(inode->i_state & I_NEW))
190 		return inode;
191 
192 	raw_inode = sysv_raw_inode(sb, ino, &bh);
193 	if (!raw_inode) {
194 		printk("Major problem: unable to read inode from dev %s\n",
195 		       inode->i_sb->s_id);
196 		goto bad_inode;
197 	}
198 	/* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
199 	inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
200 	i_uid_write(inode, (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid));
201 	i_gid_write(inode, (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid));
202 	set_nlink(inode, fs16_to_cpu(sbi, raw_inode->i_nlink));
203 	inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
204 	inode->i_atime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_atime);
205 	inode->i_mtime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_mtime);
206 	inode->i_ctime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_ctime);
207 	inode->i_ctime.tv_nsec = 0;
208 	inode->i_atime.tv_nsec = 0;
209 	inode->i_mtime.tv_nsec = 0;
210 	inode->i_blocks = 0;
211 
212 	si = SYSV_I(inode);
213 	for (block = 0; block < 10+1+1+1; block++)
214 		read3byte(sbi, &raw_inode->i_data[3*block],
215 				(u8 *)&si->i_data[block]);
216 	brelse(bh);
217 	si->i_dir_start_lookup = 0;
218 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
219 		sysv_set_inode(inode,
220 			       old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
221 	else
222 		sysv_set_inode(inode, 0);
223 	unlock_new_inode(inode);
224 	return inode;
225 
226 bad_inode:
227 	iget_failed(inode);
228 	return ERR_PTR(-EIO);
229 }
230 
__sysv_write_inode(struct inode * inode,int wait)231 static int __sysv_write_inode(struct inode *inode, int wait)
232 {
233 	struct super_block * sb = inode->i_sb;
234 	struct sysv_sb_info * sbi = SYSV_SB(sb);
235 	struct buffer_head * bh;
236 	struct sysv_inode * raw_inode;
237 	struct sysv_inode_info * si;
238 	unsigned int ino, block;
239 	int err = 0;
240 
241 	ino = inode->i_ino;
242 	if (!ino || ino > sbi->s_ninodes) {
243 		printk("Bad inode number on dev %s: %d is out of range\n",
244 		       inode->i_sb->s_id, ino);
245 		return -EIO;
246 	}
247 	raw_inode = sysv_raw_inode(sb, ino, &bh);
248 	if (!raw_inode) {
249 		printk("unable to read i-node block\n");
250 		return -EIO;
251 	}
252 
253 	raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
254 	raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(i_uid_read(inode)));
255 	raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(i_gid_read(inode)));
256 	raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
257 	raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
258 	raw_inode->i_atime = cpu_to_fs32(sbi, inode->i_atime.tv_sec);
259 	raw_inode->i_mtime = cpu_to_fs32(sbi, inode->i_mtime.tv_sec);
260 	raw_inode->i_ctime = cpu_to_fs32(sbi, inode->i_ctime.tv_sec);
261 
262 	si = SYSV_I(inode);
263 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
264 		si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
265 	for (block = 0; block < 10+1+1+1; block++)
266 		write3byte(sbi, (u8 *)&si->i_data[block],
267 			&raw_inode->i_data[3*block]);
268 	mark_buffer_dirty(bh);
269 	if (wait) {
270                 sync_dirty_buffer(bh);
271                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
272                         printk ("IO error syncing sysv inode [%s:%08x]\n",
273                                 sb->s_id, ino);
274                         err = -EIO;
275                 }
276         }
277 	brelse(bh);
278 	return err;
279 }
280 
sysv_write_inode(struct inode * inode,struct writeback_control * wbc)281 int sysv_write_inode(struct inode *inode, struct writeback_control *wbc)
282 {
283 	return __sysv_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
284 }
285 
sysv_sync_inode(struct inode * inode)286 int sysv_sync_inode(struct inode *inode)
287 {
288 	return __sysv_write_inode(inode, 1);
289 }
290 
sysv_evict_inode(struct inode * inode)291 static void sysv_evict_inode(struct inode *inode)
292 {
293 	truncate_inode_pages_final(&inode->i_data);
294 	if (!inode->i_nlink) {
295 		inode->i_size = 0;
296 		sysv_truncate(inode);
297 	}
298 	invalidate_inode_buffers(inode);
299 	clear_inode(inode);
300 	if (!inode->i_nlink)
301 		sysv_free_inode(inode);
302 }
303 
304 static struct kmem_cache *sysv_inode_cachep;
305 
sysv_alloc_inode(struct super_block * sb)306 static struct inode *sysv_alloc_inode(struct super_block *sb)
307 {
308 	struct sysv_inode_info *si;
309 
310 	si = kmem_cache_alloc(sysv_inode_cachep, GFP_KERNEL);
311 	if (!si)
312 		return NULL;
313 	return &si->vfs_inode;
314 }
315 
sysv_i_callback(struct rcu_head * head)316 static void sysv_i_callback(struct rcu_head *head)
317 {
318 	struct inode *inode = container_of(head, struct inode, i_rcu);
319 	kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
320 }
321 
sysv_destroy_inode(struct inode * inode)322 static void sysv_destroy_inode(struct inode *inode)
323 {
324 	call_rcu(&inode->i_rcu, sysv_i_callback);
325 }
326 
init_once(void * p)327 static void init_once(void *p)
328 {
329 	struct sysv_inode_info *si = (struct sysv_inode_info *)p;
330 
331 	inode_init_once(&si->vfs_inode);
332 }
333 
334 const struct super_operations sysv_sops = {
335 	.alloc_inode	= sysv_alloc_inode,
336 	.destroy_inode	= sysv_destroy_inode,
337 	.write_inode	= sysv_write_inode,
338 	.evict_inode	= sysv_evict_inode,
339 	.put_super	= sysv_put_super,
340 	.sync_fs	= sysv_sync_fs,
341 	.remount_fs	= sysv_remount,
342 	.statfs		= sysv_statfs,
343 };
344 
sysv_init_icache(void)345 int __init sysv_init_icache(void)
346 {
347 	sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
348 			sizeof(struct sysv_inode_info), 0,
349 			SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
350 			init_once);
351 	if (!sysv_inode_cachep)
352 		return -ENOMEM;
353 	return 0;
354 }
355 
sysv_destroy_icache(void)356 void sysv_destroy_icache(void)
357 {
358 	/*
359 	 * Make sure all delayed rcu free inodes are flushed before we
360 	 * destroy cache.
361 	 */
362 	rcu_barrier();
363 	kmem_cache_destroy(sysv_inode_cachep);
364 }
365