xref: /openbmc/linux/fs/sysv/inode.c (revision 2a598d0b)
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 
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 
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 
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 
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 = u64_to_fsid(id);
102 	return 0;
103 }
104 
105 /*
106  * NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
107  */
108 static 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 
129 static 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 
147 static const struct inode_operations sysv_symlink_inode_operations = {
148 	.get_link	= page_get_link,
149 	.getattr	= sysv_getattr,
150 };
151 
152 void 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 
170 struct 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->i_atime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_atime);
204 	inode->i_mtime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_mtime);
205 	inode->i_ctime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_ctime);
206 	inode->i_ctime.tv_nsec = 0;
207 	inode->i_atime.tv_nsec = 0;
208 	inode->i_mtime.tv_nsec = 0;
209 	inode->i_blocks = 0;
210 
211 	si = SYSV_I(inode);
212 	for (block = 0; block < 10+1+1+1; block++)
213 		read3byte(sbi, &raw_inode->i_data[3*block],
214 				(u8 *)&si->i_data[block]);
215 	brelse(bh);
216 	si->i_dir_start_lookup = 0;
217 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
218 		sysv_set_inode(inode,
219 			       old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
220 	else
221 		sysv_set_inode(inode, 0);
222 	unlock_new_inode(inode);
223 	return inode;
224 
225 bad_inode:
226 	iget_failed(inode);
227 	return ERR_PTR(-EIO);
228 }
229 
230 static int __sysv_write_inode(struct inode *inode, int wait)
231 {
232 	struct super_block * sb = inode->i_sb;
233 	struct sysv_sb_info * sbi = SYSV_SB(sb);
234 	struct buffer_head * bh;
235 	struct sysv_inode * raw_inode;
236 	struct sysv_inode_info * si;
237 	unsigned int ino, block;
238 	int err = 0;
239 
240 	ino = inode->i_ino;
241 	if (!ino || ino > sbi->s_ninodes) {
242 		printk("Bad inode number on dev %s: %d is out of range\n",
243 		       inode->i_sb->s_id, ino);
244 		return -EIO;
245 	}
246 	raw_inode = sysv_raw_inode(sb, ino, &bh);
247 	if (!raw_inode) {
248 		printk("unable to read i-node block\n");
249 		return -EIO;
250 	}
251 
252 	raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
253 	raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(i_uid_read(inode)));
254 	raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(i_gid_read(inode)));
255 	raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
256 	raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
257 	raw_inode->i_atime = cpu_to_fs32(sbi, inode->i_atime.tv_sec);
258 	raw_inode->i_mtime = cpu_to_fs32(sbi, inode->i_mtime.tv_sec);
259 	raw_inode->i_ctime = cpu_to_fs32(sbi, inode->i_ctime.tv_sec);
260 
261 	si = SYSV_I(inode);
262 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
263 		si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
264 	for (block = 0; block < 10+1+1+1; block++)
265 		write3byte(sbi, (u8 *)&si->i_data[block],
266 			&raw_inode->i_data[3*block]);
267 	mark_buffer_dirty(bh);
268 	if (wait) {
269                 sync_dirty_buffer(bh);
270                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
271                         printk ("IO error syncing sysv inode [%s:%08x]\n",
272                                 sb->s_id, ino);
273                         err = -EIO;
274                 }
275         }
276 	brelse(bh);
277 	return err;
278 }
279 
280 int sysv_write_inode(struct inode *inode, struct writeback_control *wbc)
281 {
282 	return __sysv_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
283 }
284 
285 int sysv_sync_inode(struct inode *inode)
286 {
287 	return __sysv_write_inode(inode, 1);
288 }
289 
290 static void sysv_evict_inode(struct inode *inode)
291 {
292 	truncate_inode_pages_final(&inode->i_data);
293 	if (!inode->i_nlink) {
294 		inode->i_size = 0;
295 		sysv_truncate(inode);
296 	}
297 	invalidate_inode_buffers(inode);
298 	clear_inode(inode);
299 	if (!inode->i_nlink)
300 		sysv_free_inode(inode);
301 }
302 
303 static struct kmem_cache *sysv_inode_cachep;
304 
305 static struct inode *sysv_alloc_inode(struct super_block *sb)
306 {
307 	struct sysv_inode_info *si;
308 
309 	si = alloc_inode_sb(sb, sysv_inode_cachep, GFP_KERNEL);
310 	if (!si)
311 		return NULL;
312 	return &si->vfs_inode;
313 }
314 
315 static void sysv_free_in_core_inode(struct inode *inode)
316 {
317 	kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
318 }
319 
320 static void init_once(void *p)
321 {
322 	struct sysv_inode_info *si = (struct sysv_inode_info *)p;
323 
324 	inode_init_once(&si->vfs_inode);
325 }
326 
327 const struct super_operations sysv_sops = {
328 	.alloc_inode	= sysv_alloc_inode,
329 	.free_inode	= sysv_free_in_core_inode,
330 	.write_inode	= sysv_write_inode,
331 	.evict_inode	= sysv_evict_inode,
332 	.put_super	= sysv_put_super,
333 	.sync_fs	= sysv_sync_fs,
334 	.remount_fs	= sysv_remount,
335 	.statfs		= sysv_statfs,
336 };
337 
338 int __init sysv_init_icache(void)
339 {
340 	sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
341 			sizeof(struct sysv_inode_info), 0,
342 			SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
343 			init_once);
344 	if (!sysv_inode_cachep)
345 		return -ENOMEM;
346 	return 0;
347 }
348 
349 void sysv_destroy_icache(void)
350 {
351 	/*
352 	 * Make sure all delayed rcu free inodes are flushed before we
353 	 * destroy cache.
354 	 */
355 	rcu_barrier();
356 	kmem_cache_destroy(sysv_inode_cachep);
357 }
358