1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * fs/bfs/dir.c |
4 | * BFS directory operations. |
5 | * Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com> |
6 | * Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005 |
7 | */ |
8 | |
9 | #include <linux/time.h> |
10 | #include <linux/string.h> |
11 | #include <linux/fs.h> |
12 | #include <linux/buffer_head.h> |
13 | #include <linux/sched.h> |
14 | #include "bfs.h" |
15 | |
16 | #undef DEBUG |
17 | |
18 | #ifdef DEBUG |
19 | #define dprintf(x...) printf(x) |
20 | #else |
21 | #define dprintf(x...) |
22 | #endif |
23 | |
24 | static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino); |
25 | static struct buffer_head *bfs_find_entry(struct inode *dir, |
26 | const struct qstr *child, |
27 | struct bfs_dirent **res_dir); |
28 | |
29 | static int bfs_readdir(struct file *f, struct dir_context *ctx) |
30 | { |
31 | struct inode *dir = file_inode(f); |
32 | struct buffer_head *bh; |
33 | struct bfs_dirent *de; |
34 | unsigned int offset; |
35 | int block; |
36 | |
37 | if (ctx->pos & (BFS_DIRENT_SIZE - 1)) { |
38 | printf("Bad f_pos=%08lx for %s:%08lx\n" , |
39 | (unsigned long)ctx->pos, |
40 | dir->i_sb->s_id, dir->i_ino); |
41 | return -EINVAL; |
42 | } |
43 | |
44 | while (ctx->pos < dir->i_size) { |
45 | offset = ctx->pos & (BFS_BSIZE - 1); |
46 | block = BFS_I(inode: dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS); |
47 | bh = sb_bread(sb: dir->i_sb, block); |
48 | if (!bh) { |
49 | ctx->pos += BFS_BSIZE - offset; |
50 | continue; |
51 | } |
52 | do { |
53 | de = (struct bfs_dirent *)(bh->b_data + offset); |
54 | if (de->ino) { |
55 | int size = strnlen(p: de->name, BFS_NAMELEN); |
56 | if (!dir_emit(ctx, name: de->name, namelen: size, |
57 | le16_to_cpu(de->ino), |
58 | DT_UNKNOWN)) { |
59 | brelse(bh); |
60 | return 0; |
61 | } |
62 | } |
63 | offset += BFS_DIRENT_SIZE; |
64 | ctx->pos += BFS_DIRENT_SIZE; |
65 | } while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size)); |
66 | brelse(bh); |
67 | } |
68 | return 0; |
69 | } |
70 | |
71 | const struct file_operations bfs_dir_operations = { |
72 | .read = generic_read_dir, |
73 | .iterate_shared = bfs_readdir, |
74 | .fsync = generic_file_fsync, |
75 | .llseek = generic_file_llseek, |
76 | }; |
77 | |
78 | static int bfs_create(struct mnt_idmap *idmap, struct inode *dir, |
79 | struct dentry *dentry, umode_t mode, bool excl) |
80 | { |
81 | int err; |
82 | struct inode *inode; |
83 | struct super_block *s = dir->i_sb; |
84 | struct bfs_sb_info *info = BFS_SB(sb: s); |
85 | unsigned long ino; |
86 | |
87 | inode = new_inode(sb: s); |
88 | if (!inode) |
89 | return -ENOMEM; |
90 | mutex_lock(&info->bfs_lock); |
91 | ino = find_first_zero_bit(addr: info->si_imap, size: info->si_lasti + 1); |
92 | if (ino > info->si_lasti) { |
93 | mutex_unlock(lock: &info->bfs_lock); |
94 | iput(inode); |
95 | return -ENOSPC; |
96 | } |
97 | set_bit(nr: ino, addr: info->si_imap); |
98 | info->si_freei--; |
99 | inode_init_owner(idmap: &nop_mnt_idmap, inode, dir, mode); |
100 | simple_inode_init_ts(inode); |
101 | inode->i_blocks = 0; |
102 | inode->i_op = &bfs_file_inops; |
103 | inode->i_fop = &bfs_file_operations; |
104 | inode->i_mapping->a_ops = &bfs_aops; |
105 | inode->i_ino = ino; |
106 | BFS_I(inode)->i_dsk_ino = ino; |
107 | BFS_I(inode)->i_sblock = 0; |
108 | BFS_I(inode)->i_eblock = 0; |
109 | insert_inode_hash(inode); |
110 | mark_inode_dirty(inode); |
111 | bfs_dump_imap("create" , s); |
112 | |
113 | err = bfs_add_entry(dir, child: &dentry->d_name, ino: inode->i_ino); |
114 | if (err) { |
115 | inode_dec_link_count(inode); |
116 | mutex_unlock(lock: &info->bfs_lock); |
117 | iput(inode); |
118 | return err; |
119 | } |
120 | mutex_unlock(lock: &info->bfs_lock); |
121 | d_instantiate(dentry, inode); |
122 | return 0; |
123 | } |
124 | |
125 | static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry, |
126 | unsigned int flags) |
127 | { |
128 | struct inode *inode = NULL; |
129 | struct buffer_head *bh; |
130 | struct bfs_dirent *de; |
131 | struct bfs_sb_info *info = BFS_SB(sb: dir->i_sb); |
132 | |
133 | if (dentry->d_name.len > BFS_NAMELEN) |
134 | return ERR_PTR(error: -ENAMETOOLONG); |
135 | |
136 | mutex_lock(&info->bfs_lock); |
137 | bh = bfs_find_entry(dir, child: &dentry->d_name, res_dir: &de); |
138 | if (bh) { |
139 | unsigned long ino = (unsigned long)le16_to_cpu(de->ino); |
140 | brelse(bh); |
141 | inode = bfs_iget(sb: dir->i_sb, ino); |
142 | } |
143 | mutex_unlock(lock: &info->bfs_lock); |
144 | return d_splice_alias(inode, dentry); |
145 | } |
146 | |
147 | static int bfs_link(struct dentry *old, struct inode *dir, |
148 | struct dentry *new) |
149 | { |
150 | struct inode *inode = d_inode(dentry: old); |
151 | struct bfs_sb_info *info = BFS_SB(sb: inode->i_sb); |
152 | int err; |
153 | |
154 | mutex_lock(&info->bfs_lock); |
155 | err = bfs_add_entry(dir, child: &new->d_name, ino: inode->i_ino); |
156 | if (err) { |
157 | mutex_unlock(lock: &info->bfs_lock); |
158 | return err; |
159 | } |
160 | inc_nlink(inode); |
161 | inode_set_ctime_current(inode); |
162 | mark_inode_dirty(inode); |
163 | ihold(inode); |
164 | d_instantiate(new, inode); |
165 | mutex_unlock(lock: &info->bfs_lock); |
166 | return 0; |
167 | } |
168 | |
169 | static int bfs_unlink(struct inode *dir, struct dentry *dentry) |
170 | { |
171 | int error = -ENOENT; |
172 | struct inode *inode = d_inode(dentry); |
173 | struct buffer_head *bh; |
174 | struct bfs_dirent *de; |
175 | struct bfs_sb_info *info = BFS_SB(sb: inode->i_sb); |
176 | |
177 | mutex_lock(&info->bfs_lock); |
178 | bh = bfs_find_entry(dir, child: &dentry->d_name, res_dir: &de); |
179 | if (!bh || (le16_to_cpu(de->ino) != inode->i_ino)) |
180 | goto out_brelse; |
181 | |
182 | if (!inode->i_nlink) { |
183 | printf("unlinking non-existent file %s:%lu (nlink=%d)\n" , |
184 | inode->i_sb->s_id, inode->i_ino, |
185 | inode->i_nlink); |
186 | set_nlink(inode, nlink: 1); |
187 | } |
188 | de->ino = 0; |
189 | mark_buffer_dirty_inode(bh, inode: dir); |
190 | inode_set_mtime_to_ts(inode: dir, ts: inode_set_ctime_current(inode: dir)); |
191 | mark_inode_dirty(inode: dir); |
192 | inode_set_ctime_to_ts(inode, ts: inode_get_ctime(inode: dir)); |
193 | inode_dec_link_count(inode); |
194 | error = 0; |
195 | |
196 | out_brelse: |
197 | brelse(bh); |
198 | mutex_unlock(lock: &info->bfs_lock); |
199 | return error; |
200 | } |
201 | |
202 | static int bfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, |
203 | struct dentry *old_dentry, struct inode *new_dir, |
204 | struct dentry *new_dentry, unsigned int flags) |
205 | { |
206 | struct inode *old_inode, *new_inode; |
207 | struct buffer_head *old_bh, *new_bh; |
208 | struct bfs_dirent *old_de, *new_de; |
209 | struct bfs_sb_info *info; |
210 | int error = -ENOENT; |
211 | |
212 | if (flags & ~RENAME_NOREPLACE) |
213 | return -EINVAL; |
214 | |
215 | old_bh = new_bh = NULL; |
216 | old_inode = d_inode(dentry: old_dentry); |
217 | if (S_ISDIR(old_inode->i_mode)) |
218 | return -EINVAL; |
219 | |
220 | info = BFS_SB(sb: old_inode->i_sb); |
221 | |
222 | mutex_lock(&info->bfs_lock); |
223 | old_bh = bfs_find_entry(dir: old_dir, child: &old_dentry->d_name, res_dir: &old_de); |
224 | |
225 | if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino)) |
226 | goto end_rename; |
227 | |
228 | error = -EPERM; |
229 | new_inode = d_inode(dentry: new_dentry); |
230 | new_bh = bfs_find_entry(dir: new_dir, child: &new_dentry->d_name, res_dir: &new_de); |
231 | |
232 | if (new_bh && !new_inode) { |
233 | brelse(bh: new_bh); |
234 | new_bh = NULL; |
235 | } |
236 | if (!new_bh) { |
237 | error = bfs_add_entry(dir: new_dir, child: &new_dentry->d_name, |
238 | ino: old_inode->i_ino); |
239 | if (error) |
240 | goto end_rename; |
241 | } |
242 | old_de->ino = 0; |
243 | inode_set_mtime_to_ts(inode: old_dir, ts: inode_set_ctime_current(inode: old_dir)); |
244 | mark_inode_dirty(inode: old_dir); |
245 | if (new_inode) { |
246 | inode_set_ctime_current(inode: new_inode); |
247 | inode_dec_link_count(inode: new_inode); |
248 | } |
249 | mark_buffer_dirty_inode(bh: old_bh, inode: old_dir); |
250 | error = 0; |
251 | |
252 | end_rename: |
253 | mutex_unlock(lock: &info->bfs_lock); |
254 | brelse(bh: old_bh); |
255 | brelse(bh: new_bh); |
256 | return error; |
257 | } |
258 | |
259 | const struct inode_operations bfs_dir_inops = { |
260 | .create = bfs_create, |
261 | .lookup = bfs_lookup, |
262 | .link = bfs_link, |
263 | .unlink = bfs_unlink, |
264 | .rename = bfs_rename, |
265 | }; |
266 | |
267 | static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino) |
268 | { |
269 | const unsigned char *name = child->name; |
270 | int namelen = child->len; |
271 | struct buffer_head *bh; |
272 | struct bfs_dirent *de; |
273 | int block, sblock, eblock, off, pos; |
274 | int i; |
275 | |
276 | dprintf("name=%s, namelen=%d\n" , name, namelen); |
277 | |
278 | sblock = BFS_I(inode: dir)->i_sblock; |
279 | eblock = BFS_I(inode: dir)->i_eblock; |
280 | for (block = sblock; block <= eblock; block++) { |
281 | bh = sb_bread(sb: dir->i_sb, block); |
282 | if (!bh) |
283 | return -EIO; |
284 | for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) { |
285 | de = (struct bfs_dirent *)(bh->b_data + off); |
286 | if (!de->ino) { |
287 | pos = (block - sblock) * BFS_BSIZE + off; |
288 | if (pos >= dir->i_size) { |
289 | dir->i_size += BFS_DIRENT_SIZE; |
290 | inode_set_ctime_current(inode: dir); |
291 | } |
292 | inode_set_mtime_to_ts(inode: dir, |
293 | ts: inode_set_ctime_current(inode: dir)); |
294 | mark_inode_dirty(inode: dir); |
295 | de->ino = cpu_to_le16((u16)ino); |
296 | for (i = 0; i < BFS_NAMELEN; i++) |
297 | de->name[i] = |
298 | (i < namelen) ? name[i] : 0; |
299 | mark_buffer_dirty_inode(bh, inode: dir); |
300 | brelse(bh); |
301 | return 0; |
302 | } |
303 | } |
304 | brelse(bh); |
305 | } |
306 | return -ENOSPC; |
307 | } |
308 | |
309 | static inline int bfs_namecmp(int len, const unsigned char *name, |
310 | const char *buffer) |
311 | { |
312 | if ((len < BFS_NAMELEN) && buffer[len]) |
313 | return 0; |
314 | return !memcmp(p: name, q: buffer, size: len); |
315 | } |
316 | |
317 | static struct buffer_head *bfs_find_entry(struct inode *dir, |
318 | const struct qstr *child, |
319 | struct bfs_dirent **res_dir) |
320 | { |
321 | unsigned long block = 0, offset = 0; |
322 | struct buffer_head *bh = NULL; |
323 | struct bfs_dirent *de; |
324 | const unsigned char *name = child->name; |
325 | int namelen = child->len; |
326 | |
327 | *res_dir = NULL; |
328 | if (namelen > BFS_NAMELEN) |
329 | return NULL; |
330 | |
331 | while (block * BFS_BSIZE + offset < dir->i_size) { |
332 | if (!bh) { |
333 | bh = sb_bread(sb: dir->i_sb, block: BFS_I(inode: dir)->i_sblock + block); |
334 | if (!bh) { |
335 | block++; |
336 | continue; |
337 | } |
338 | } |
339 | de = (struct bfs_dirent *)(bh->b_data + offset); |
340 | offset += BFS_DIRENT_SIZE; |
341 | if (le16_to_cpu(de->ino) && |
342 | bfs_namecmp(len: namelen, name, buffer: de->name)) { |
343 | *res_dir = de; |
344 | return bh; |
345 | } |
346 | if (offset < bh->b_size) |
347 | continue; |
348 | brelse(bh); |
349 | bh = NULL; |
350 | offset = 0; |
351 | block++; |
352 | } |
353 | brelse(bh); |
354 | return NULL; |
355 | } |
356 | |