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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * inode.c | |
4 | * | |
5 | * Copyright (c) 1999 Al Smith | |
6 | * | |
7 | * Portions derived from work (c) 1995,1996 Christian Vogelgsang, | |
8 | * and from work (c) 1998 Mike Shaver. | |
9 | */ | |
10 | ||
1da177e4 LT |
11 | #include <linux/buffer_head.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/fs.h> | |
45254b4f CH |
14 | #include "efs.h" |
15 | #include <linux/efs_fs_sb.h> | |
1da177e4 LT |
16 | |
17 | static int efs_readpage(struct file *file, struct page *page) | |
18 | { | |
19 | return block_read_full_page(page,efs_get_block); | |
20 | } | |
21 | static sector_t _efs_bmap(struct address_space *mapping, sector_t block) | |
22 | { | |
23 | return generic_block_bmap(mapping,block,efs_get_block); | |
24 | } | |
f5e54d6e | 25 | static const struct address_space_operations efs_aops = { |
1da177e4 | 26 | .readpage = efs_readpage, |
1da177e4 LT |
27 | .bmap = _efs_bmap |
28 | }; | |
29 | ||
30 | static inline void extent_copy(efs_extent *src, efs_extent *dst) { | |
31 | /* | |
32 | * this is slightly evil. it doesn't just copy | |
33 | * efs_extent from src to dst, it also mangles | |
34 | * the bits so that dst ends up in cpu byte-order. | |
35 | */ | |
36 | ||
37 | dst->cooked.ex_magic = (unsigned int) src->raw[0]; | |
38 | dst->cooked.ex_bn = ((unsigned int) src->raw[1] << 16) | | |
39 | ((unsigned int) src->raw[2] << 8) | | |
40 | ((unsigned int) src->raw[3] << 0); | |
41 | dst->cooked.ex_length = (unsigned int) src->raw[4]; | |
42 | dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) | | |
43 | ((unsigned int) src->raw[6] << 8) | | |
44 | ((unsigned int) src->raw[7] << 0); | |
45 | return; | |
46 | } | |
47 | ||
298384cd | 48 | struct inode *efs_iget(struct super_block *super, unsigned long ino) |
1da177e4 LT |
49 | { |
50 | int i, inode_index; | |
51 | dev_t device; | |
52 | u32 rdev; | |
53 | struct buffer_head *bh; | |
298384cd DH |
54 | struct efs_sb_info *sb = SUPER_INFO(super); |
55 | struct efs_inode_info *in; | |
1da177e4 LT |
56 | efs_block_t block, offset; |
57 | struct efs_dinode *efs_inode; | |
298384cd DH |
58 | struct inode *inode; |
59 | ||
60 | inode = iget_locked(super, ino); | |
136eefa4 | 61 | if (!inode) |
298384cd DH |
62 | return ERR_PTR(-ENOMEM); |
63 | if (!(inode->i_state & I_NEW)) | |
64 | return inode; | |
65 | ||
66 | in = INODE_INFO(inode); | |
67 | ||
1da177e4 LT |
68 | /* |
69 | ** EFS layout: | |
70 | ** | |
71 | ** | cylinder group | cylinder group | cylinder group ..etc | |
72 | ** |inodes|data |inodes|data |inodes|data ..etc | |
73 | ** | |
74 | ** work out the inode block index, (considering initially that the | |
75 | ** inodes are stored as consecutive blocks). then work out the block | |
76 | ** number of that inode given the above layout, and finally the | |
77 | ** offset of the inode within that block. | |
78 | */ | |
79 | ||
80 | inode_index = inode->i_ino / | |
81 | (EFS_BLOCKSIZE / sizeof(struct efs_dinode)); | |
82 | ||
83 | block = sb->fs_start + sb->first_block + | |
84 | (sb->group_size * (inode_index / sb->inode_blocks)) + | |
85 | (inode_index % sb->inode_blocks); | |
86 | ||
87 | offset = (inode->i_ino % | |
88 | (EFS_BLOCKSIZE / sizeof(struct efs_dinode))) * | |
89 | sizeof(struct efs_dinode); | |
90 | ||
91 | bh = sb_bread(inode->i_sb, block); | |
92 | if (!bh) { | |
f403d1db | 93 | pr_warn("%s() failed at block %d\n", __func__, block); |
1da177e4 LT |
94 | goto read_inode_error; |
95 | } | |
96 | ||
97 | efs_inode = (struct efs_dinode *) (bh->b_data + offset); | |
98 | ||
99 | inode->i_mode = be16_to_cpu(efs_inode->di_mode); | |
bfe86848 | 100 | set_nlink(inode, be16_to_cpu(efs_inode->di_nlink)); |
5d4ea4da EB |
101 | i_uid_write(inode, (uid_t)be16_to_cpu(efs_inode->di_uid)); |
102 | i_gid_write(inode, (gid_t)be16_to_cpu(efs_inode->di_gid)); | |
1da177e4 LT |
103 | inode->i_size = be32_to_cpu(efs_inode->di_size); |
104 | inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime); | |
105 | inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime); | |
106 | inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime); | |
107 | inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0; | |
108 | ||
109 | /* this is the number of blocks in the file */ | |
110 | if (inode->i_size == 0) { | |
111 | inode->i_blocks = 0; | |
112 | } else { | |
113 | inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1; | |
114 | } | |
115 | ||
116 | rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev); | |
117 | if (rdev == 0xffff) { | |
118 | rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev); | |
119 | if (sysv_major(rdev) > 0xfff) | |
120 | device = 0; | |
121 | else | |
122 | device = MKDEV(sysv_major(rdev), sysv_minor(rdev)); | |
123 | } else | |
124 | device = old_decode_dev(rdev); | |
125 | ||
126 | /* get the number of extents for this object */ | |
127 | in->numextents = be16_to_cpu(efs_inode->di_numextents); | |
128 | in->lastextent = 0; | |
129 | ||
130 | /* copy the extents contained within the inode to memory */ | |
131 | for(i = 0; i < EFS_DIRECTEXTENTS; i++) { | |
132 | extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i])); | |
133 | if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) { | |
f403d1db FF |
134 | pr_warn("extent %d has bad magic number in inode %lu\n", |
135 | i, inode->i_ino); | |
1da177e4 LT |
136 | brelse(bh); |
137 | goto read_inode_error; | |
138 | } | |
139 | } | |
140 | ||
141 | brelse(bh); | |
d1826f2a FF |
142 | pr_debug("efs_iget(): inode %lu, extents %d, mode %o\n", |
143 | inode->i_ino, in->numextents, inode->i_mode); | |
1da177e4 LT |
144 | switch (inode->i_mode & S_IFMT) { |
145 | case S_IFDIR: | |
146 | inode->i_op = &efs_dir_inode_operations; | |
147 | inode->i_fop = &efs_dir_operations; | |
148 | break; | |
149 | case S_IFREG: | |
150 | inode->i_fop = &generic_ro_fops; | |
151 | inode->i_data.a_ops = &efs_aops; | |
152 | break; | |
153 | case S_IFLNK: | |
154 | inode->i_op = &page_symlink_inode_operations; | |
21fc61c7 | 155 | inode_nohighmem(inode); |
1da177e4 LT |
156 | inode->i_data.a_ops = &efs_symlink_aops; |
157 | break; | |
158 | case S_IFCHR: | |
159 | case S_IFBLK: | |
160 | case S_IFIFO: | |
161 | init_special_inode(inode, inode->i_mode, device); | |
162 | break; | |
163 | default: | |
f403d1db | 164 | pr_warn("unsupported inode mode %o\n", inode->i_mode); |
1da177e4 LT |
165 | goto read_inode_error; |
166 | break; | |
167 | } | |
168 | ||
298384cd DH |
169 | unlock_new_inode(inode); |
170 | return inode; | |
1da177e4 LT |
171 | |
172 | read_inode_error: | |
f403d1db | 173 | pr_warn("failed to read inode %lu\n", inode->i_ino); |
298384cd DH |
174 | iget_failed(inode); |
175 | return ERR_PTR(-EIO); | |
1da177e4 LT |
176 | } |
177 | ||
178 | static inline efs_block_t | |
179 | efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) { | |
180 | efs_block_t start; | |
181 | efs_block_t length; | |
182 | efs_block_t offset; | |
183 | ||
184 | /* | |
185 | * given an extent and a logical block within a file, | |
186 | * can this block be found within this extent ? | |
187 | */ | |
188 | start = ptr->cooked.ex_bn; | |
189 | length = ptr->cooked.ex_length; | |
190 | offset = ptr->cooked.ex_offset; | |
191 | ||
192 | if ((block >= offset) && (block < offset+length)) { | |
193 | return(sb->fs_start + start + block - offset); | |
194 | } else { | |
195 | return 0; | |
196 | } | |
197 | } | |
198 | ||
199 | efs_block_t efs_map_block(struct inode *inode, efs_block_t block) { | |
200 | struct efs_sb_info *sb = SUPER_INFO(inode->i_sb); | |
201 | struct efs_inode_info *in = INODE_INFO(inode); | |
202 | struct buffer_head *bh = NULL; | |
203 | ||
204 | int cur, last, first = 1; | |
205 | int ibase, ioffset, dirext, direxts, indext, indexts; | |
206 | efs_block_t iblock, result = 0, lastblock = 0; | |
207 | efs_extent ext, *exts; | |
208 | ||
209 | last = in->lastextent; | |
210 | ||
211 | if (in->numextents <= EFS_DIRECTEXTENTS) { | |
212 | /* first check the last extent we returned */ | |
213 | if ((result = efs_extent_check(&in->extents[last], block, sb))) | |
214 | return result; | |
215 | ||
216 | /* if we only have one extent then nothing can be found */ | |
217 | if (in->numextents == 1) { | |
f403d1db | 218 | pr_err("%s() failed to map (1 extent)\n", __func__); |
1da177e4 LT |
219 | return 0; |
220 | } | |
221 | ||
222 | direxts = in->numextents; | |
223 | ||
224 | /* | |
225 | * check the stored extents in the inode | |
226 | * start with next extent and check forwards | |
227 | */ | |
228 | for(dirext = 1; dirext < direxts; dirext++) { | |
229 | cur = (last + dirext) % in->numextents; | |
230 | if ((result = efs_extent_check(&in->extents[cur], block, sb))) { | |
231 | in->lastextent = cur; | |
232 | return result; | |
233 | } | |
234 | } | |
235 | ||
f403d1db | 236 | pr_err("%s() failed to map block %u (dir)\n", __func__, block); |
1da177e4 LT |
237 | return 0; |
238 | } | |
239 | ||
d1826f2a FF |
240 | pr_debug("%s(): indirect search for logical block %u\n", |
241 | __func__, block); | |
1da177e4 LT |
242 | direxts = in->extents[0].cooked.ex_offset; |
243 | indexts = in->numextents; | |
244 | ||
245 | for(indext = 0; indext < indexts; indext++) { | |
246 | cur = (last + indext) % indexts; | |
247 | ||
248 | /* | |
249 | * work out which direct extent contains `cur'. | |
250 | * | |
251 | * also compute ibase: i.e. the number of the first | |
252 | * indirect extent contained within direct extent `cur'. | |
253 | * | |
254 | */ | |
255 | ibase = 0; | |
256 | for(dirext = 0; cur < ibase && dirext < direxts; dirext++) { | |
257 | ibase += in->extents[dirext].cooked.ex_length * | |
258 | (EFS_BLOCKSIZE / sizeof(efs_extent)); | |
259 | } | |
260 | ||
261 | if (dirext == direxts) { | |
262 | /* should never happen */ | |
f403d1db FF |
263 | pr_err("couldn't find direct extent for indirect extent %d (block %u)\n", |
264 | cur, block); | |
1da177e4 LT |
265 | if (bh) brelse(bh); |
266 | return 0; | |
267 | } | |
268 | ||
269 | /* work out block number and offset of this indirect extent */ | |
270 | iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn + | |
271 | (cur - ibase) / | |
272 | (EFS_BLOCKSIZE / sizeof(efs_extent)); | |
273 | ioffset = (cur - ibase) % | |
274 | (EFS_BLOCKSIZE / sizeof(efs_extent)); | |
275 | ||
276 | if (first || lastblock != iblock) { | |
277 | if (bh) brelse(bh); | |
278 | ||
279 | bh = sb_bread(inode->i_sb, iblock); | |
280 | if (!bh) { | |
f403d1db FF |
281 | pr_err("%s() failed at block %d\n", |
282 | __func__, iblock); | |
1da177e4 LT |
283 | return 0; |
284 | } | |
d1826f2a FF |
285 | pr_debug("%s(): read indirect extent block %d\n", |
286 | __func__, iblock); | |
1da177e4 LT |
287 | first = 0; |
288 | lastblock = iblock; | |
289 | } | |
290 | ||
291 | exts = (efs_extent *) bh->b_data; | |
292 | ||
293 | extent_copy(&(exts[ioffset]), &ext); | |
294 | ||
295 | if (ext.cooked.ex_magic != 0) { | |
f403d1db FF |
296 | pr_err("extent %d has bad magic number in block %d\n", |
297 | cur, iblock); | |
1da177e4 LT |
298 | if (bh) brelse(bh); |
299 | return 0; | |
300 | } | |
301 | ||
302 | if ((result = efs_extent_check(&ext, block, sb))) { | |
303 | if (bh) brelse(bh); | |
304 | in->lastextent = cur; | |
305 | return result; | |
306 | } | |
307 | } | |
308 | if (bh) brelse(bh); | |
f403d1db | 309 | pr_err("%s() failed to map block %u (indir)\n", __func__, block); |
1da177e4 LT |
310 | return 0; |
311 | } | |
312 | ||
313 | MODULE_LICENSE("GPL"); |