Commit | Line | Data |
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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 | 16 | |
2c69e205 | 17 | static int efs_read_folio(struct file *file, struct folio *folio) |
1da177e4 | 18 | { |
2c69e205 | 19 | return block_read_full_folio(folio, efs_get_block); |
1da177e4 | 20 | } |
2c69e205 | 21 | |
1da177e4 LT |
22 | static sector_t _efs_bmap(struct address_space *mapping, sector_t block) |
23 | { | |
24 | return generic_block_bmap(mapping,block,efs_get_block); | |
25 | } | |
2c69e205 | 26 | |
f5e54d6e | 27 | static const struct address_space_operations efs_aops = { |
2c69e205 | 28 | .read_folio = efs_read_folio, |
1da177e4 LT |
29 | .bmap = _efs_bmap |
30 | }; | |
31 | ||
32 | static inline void extent_copy(efs_extent *src, efs_extent *dst) { | |
33 | /* | |
34 | * this is slightly evil. it doesn't just copy | |
35 | * efs_extent from src to dst, it also mangles | |
36 | * the bits so that dst ends up in cpu byte-order. | |
37 | */ | |
38 | ||
39 | dst->cooked.ex_magic = (unsigned int) src->raw[0]; | |
40 | dst->cooked.ex_bn = ((unsigned int) src->raw[1] << 16) | | |
41 | ((unsigned int) src->raw[2] << 8) | | |
42 | ((unsigned int) src->raw[3] << 0); | |
43 | dst->cooked.ex_length = (unsigned int) src->raw[4]; | |
44 | dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) | | |
45 | ((unsigned int) src->raw[6] << 8) | | |
46 | ((unsigned int) src->raw[7] << 0); | |
47 | return; | |
48 | } | |
49 | ||
298384cd | 50 | struct inode *efs_iget(struct super_block *super, unsigned long ino) |
1da177e4 LT |
51 | { |
52 | int i, inode_index; | |
53 | dev_t device; | |
54 | u32 rdev; | |
55 | struct buffer_head *bh; | |
298384cd DH |
56 | struct efs_sb_info *sb = SUPER_INFO(super); |
57 | struct efs_inode_info *in; | |
1da177e4 LT |
58 | efs_block_t block, offset; |
59 | struct efs_dinode *efs_inode; | |
298384cd DH |
60 | struct inode *inode; |
61 | ||
62 | inode = iget_locked(super, ino); | |
136eefa4 | 63 | if (!inode) |
298384cd DH |
64 | return ERR_PTR(-ENOMEM); |
65 | if (!(inode->i_state & I_NEW)) | |
66 | return inode; | |
67 | ||
68 | in = INODE_INFO(inode); | |
69 | ||
1da177e4 LT |
70 | /* |
71 | ** EFS layout: | |
72 | ** | |
73 | ** | cylinder group | cylinder group | cylinder group ..etc | |
74 | ** |inodes|data |inodes|data |inodes|data ..etc | |
75 | ** | |
76 | ** work out the inode block index, (considering initially that the | |
77 | ** inodes are stored as consecutive blocks). then work out the block | |
78 | ** number of that inode given the above layout, and finally the | |
79 | ** offset of the inode within that block. | |
80 | */ | |
81 | ||
82 | inode_index = inode->i_ino / | |
83 | (EFS_BLOCKSIZE / sizeof(struct efs_dinode)); | |
84 | ||
85 | block = sb->fs_start + sb->first_block + | |
86 | (sb->group_size * (inode_index / sb->inode_blocks)) + | |
87 | (inode_index % sb->inode_blocks); | |
88 | ||
89 | offset = (inode->i_ino % | |
90 | (EFS_BLOCKSIZE / sizeof(struct efs_dinode))) * | |
91 | sizeof(struct efs_dinode); | |
92 | ||
93 | bh = sb_bread(inode->i_sb, block); | |
94 | if (!bh) { | |
f403d1db | 95 | pr_warn("%s() failed at block %d\n", __func__, block); |
1da177e4 LT |
96 | goto read_inode_error; |
97 | } | |
98 | ||
99 | efs_inode = (struct efs_dinode *) (bh->b_data + offset); | |
100 | ||
101 | inode->i_mode = be16_to_cpu(efs_inode->di_mode); | |
bfe86848 | 102 | set_nlink(inode, be16_to_cpu(efs_inode->di_nlink)); |
5d4ea4da EB |
103 | i_uid_write(inode, (uid_t)be16_to_cpu(efs_inode->di_uid)); |
104 | i_gid_write(inode, (gid_t)be16_to_cpu(efs_inode->di_gid)); | |
1da177e4 LT |
105 | inode->i_size = be32_to_cpu(efs_inode->di_size); |
106 | inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime); | |
107 | inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime); | |
108 | inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime); | |
109 | inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0; | |
110 | ||
111 | /* this is the number of blocks in the file */ | |
112 | if (inode->i_size == 0) { | |
113 | inode->i_blocks = 0; | |
114 | } else { | |
115 | inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1; | |
116 | } | |
117 | ||
118 | rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev); | |
119 | if (rdev == 0xffff) { | |
120 | rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev); | |
121 | if (sysv_major(rdev) > 0xfff) | |
122 | device = 0; | |
123 | else | |
124 | device = MKDEV(sysv_major(rdev), sysv_minor(rdev)); | |
125 | } else | |
126 | device = old_decode_dev(rdev); | |
127 | ||
128 | /* get the number of extents for this object */ | |
129 | in->numextents = be16_to_cpu(efs_inode->di_numextents); | |
130 | in->lastextent = 0; | |
131 | ||
132 | /* copy the extents contained within the inode to memory */ | |
133 | for(i = 0; i < EFS_DIRECTEXTENTS; i++) { | |
134 | extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i])); | |
135 | if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) { | |
f403d1db FF |
136 | pr_warn("extent %d has bad magic number in inode %lu\n", |
137 | i, inode->i_ino); | |
1da177e4 LT |
138 | brelse(bh); |
139 | goto read_inode_error; | |
140 | } | |
141 | } | |
142 | ||
143 | brelse(bh); | |
d1826f2a FF |
144 | pr_debug("efs_iget(): inode %lu, extents %d, mode %o\n", |
145 | inode->i_ino, in->numextents, inode->i_mode); | |
1da177e4 LT |
146 | switch (inode->i_mode & S_IFMT) { |
147 | case S_IFDIR: | |
148 | inode->i_op = &efs_dir_inode_operations; | |
149 | inode->i_fop = &efs_dir_operations; | |
150 | break; | |
151 | case S_IFREG: | |
152 | inode->i_fop = &generic_ro_fops; | |
153 | inode->i_data.a_ops = &efs_aops; | |
154 | break; | |
155 | case S_IFLNK: | |
156 | inode->i_op = &page_symlink_inode_operations; | |
21fc61c7 | 157 | inode_nohighmem(inode); |
1da177e4 LT |
158 | inode->i_data.a_ops = &efs_symlink_aops; |
159 | break; | |
160 | case S_IFCHR: | |
161 | case S_IFBLK: | |
162 | case S_IFIFO: | |
163 | init_special_inode(inode, inode->i_mode, device); | |
164 | break; | |
165 | default: | |
f403d1db | 166 | pr_warn("unsupported inode mode %o\n", inode->i_mode); |
1da177e4 LT |
167 | goto read_inode_error; |
168 | break; | |
169 | } | |
170 | ||
298384cd DH |
171 | unlock_new_inode(inode); |
172 | return inode; | |
1da177e4 LT |
173 | |
174 | read_inode_error: | |
f403d1db | 175 | pr_warn("failed to read inode %lu\n", inode->i_ino); |
298384cd DH |
176 | iget_failed(inode); |
177 | return ERR_PTR(-EIO); | |
1da177e4 LT |
178 | } |
179 | ||
180 | static inline efs_block_t | |
181 | efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) { | |
182 | efs_block_t start; | |
183 | efs_block_t length; | |
184 | efs_block_t offset; | |
185 | ||
186 | /* | |
187 | * given an extent and a logical block within a file, | |
188 | * can this block be found within this extent ? | |
189 | */ | |
190 | start = ptr->cooked.ex_bn; | |
191 | length = ptr->cooked.ex_length; | |
192 | offset = ptr->cooked.ex_offset; | |
193 | ||
194 | if ((block >= offset) && (block < offset+length)) { | |
195 | return(sb->fs_start + start + block - offset); | |
196 | } else { | |
197 | return 0; | |
198 | } | |
199 | } | |
200 | ||
201 | efs_block_t efs_map_block(struct inode *inode, efs_block_t block) { | |
202 | struct efs_sb_info *sb = SUPER_INFO(inode->i_sb); | |
203 | struct efs_inode_info *in = INODE_INFO(inode); | |
204 | struct buffer_head *bh = NULL; | |
205 | ||
206 | int cur, last, first = 1; | |
207 | int ibase, ioffset, dirext, direxts, indext, indexts; | |
208 | efs_block_t iblock, result = 0, lastblock = 0; | |
209 | efs_extent ext, *exts; | |
210 | ||
211 | last = in->lastextent; | |
212 | ||
213 | if (in->numextents <= EFS_DIRECTEXTENTS) { | |
214 | /* first check the last extent we returned */ | |
215 | if ((result = efs_extent_check(&in->extents[last], block, sb))) | |
216 | return result; | |
217 | ||
218 | /* if we only have one extent then nothing can be found */ | |
219 | if (in->numextents == 1) { | |
f403d1db | 220 | pr_err("%s() failed to map (1 extent)\n", __func__); |
1da177e4 LT |
221 | return 0; |
222 | } | |
223 | ||
224 | direxts = in->numextents; | |
225 | ||
226 | /* | |
227 | * check the stored extents in the inode | |
228 | * start with next extent and check forwards | |
229 | */ | |
230 | for(dirext = 1; dirext < direxts; dirext++) { | |
231 | cur = (last + dirext) % in->numextents; | |
232 | if ((result = efs_extent_check(&in->extents[cur], block, sb))) { | |
233 | in->lastextent = cur; | |
234 | return result; | |
235 | } | |
236 | } | |
237 | ||
f403d1db | 238 | pr_err("%s() failed to map block %u (dir)\n", __func__, block); |
1da177e4 LT |
239 | return 0; |
240 | } | |
241 | ||
d1826f2a FF |
242 | pr_debug("%s(): indirect search for logical block %u\n", |
243 | __func__, block); | |
1da177e4 LT |
244 | direxts = in->extents[0].cooked.ex_offset; |
245 | indexts = in->numextents; | |
246 | ||
247 | for(indext = 0; indext < indexts; indext++) { | |
248 | cur = (last + indext) % indexts; | |
249 | ||
250 | /* | |
251 | * work out which direct extent contains `cur'. | |
252 | * | |
253 | * also compute ibase: i.e. the number of the first | |
254 | * indirect extent contained within direct extent `cur'. | |
255 | * | |
256 | */ | |
257 | ibase = 0; | |
258 | for(dirext = 0; cur < ibase && dirext < direxts; dirext++) { | |
259 | ibase += in->extents[dirext].cooked.ex_length * | |
260 | (EFS_BLOCKSIZE / sizeof(efs_extent)); | |
261 | } | |
262 | ||
263 | if (dirext == direxts) { | |
264 | /* should never happen */ | |
f403d1db FF |
265 | pr_err("couldn't find direct extent for indirect extent %d (block %u)\n", |
266 | cur, block); | |
1da177e4 LT |
267 | if (bh) brelse(bh); |
268 | return 0; | |
269 | } | |
270 | ||
271 | /* work out block number and offset of this indirect extent */ | |
272 | iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn + | |
273 | (cur - ibase) / | |
274 | (EFS_BLOCKSIZE / sizeof(efs_extent)); | |
275 | ioffset = (cur - ibase) % | |
276 | (EFS_BLOCKSIZE / sizeof(efs_extent)); | |
277 | ||
278 | if (first || lastblock != iblock) { | |
279 | if (bh) brelse(bh); | |
280 | ||
281 | bh = sb_bread(inode->i_sb, iblock); | |
282 | if (!bh) { | |
f403d1db FF |
283 | pr_err("%s() failed at block %d\n", |
284 | __func__, iblock); | |
1da177e4 LT |
285 | return 0; |
286 | } | |
d1826f2a FF |
287 | pr_debug("%s(): read indirect extent block %d\n", |
288 | __func__, iblock); | |
1da177e4 LT |
289 | first = 0; |
290 | lastblock = iblock; | |
291 | } | |
292 | ||
293 | exts = (efs_extent *) bh->b_data; | |
294 | ||
295 | extent_copy(&(exts[ioffset]), &ext); | |
296 | ||
297 | if (ext.cooked.ex_magic != 0) { | |
f403d1db FF |
298 | pr_err("extent %d has bad magic number in block %d\n", |
299 | cur, iblock); | |
1da177e4 LT |
300 | if (bh) brelse(bh); |
301 | return 0; | |
302 | } | |
303 | ||
304 | if ((result = efs_extent_check(&ext, block, sb))) { | |
305 | if (bh) brelse(bh); | |
306 | in->lastextent = cur; | |
307 | return result; | |
308 | } | |
309 | } | |
310 | if (bh) brelse(bh); | |
f403d1db | 311 | pr_err("%s() failed to map block %u (indir)\n", __func__, block); |
1da177e4 LT |
312 | return 0; |
313 | } | |
314 | ||
315 | MODULE_LICENSE("GPL"); |