Commit | Line | Data |
---|---|---|
5db53f3e JE |
1 | /* |
2 | * fs/logfs/dev_mtd.c - Device access methods for MTD | |
3 | * | |
4 | * As should be obvious for Linux kernel code, license is GPLv2 | |
5 | * | |
6 | * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> | |
7 | */ | |
8 | #include "logfs.h" | |
9 | #include <linux/completion.h> | |
10 | #include <linux/mount.h> | |
11 | #include <linux/sched.h> | |
6f485b41 | 12 | #include <linux/slab.h> |
5db53f3e JE |
13 | |
14 | #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) | |
15 | ||
48d36102 AB |
16 | static int logfs_mtd_read(struct super_block *sb, loff_t ofs, size_t len, |
17 | void *buf) | |
5db53f3e JE |
18 | { |
19 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
20 | size_t retlen; | |
21 | int ret; | |
22 | ||
329ad399 | 23 | ret = mtd_read(mtd, ofs, len, &retlen, buf); |
5db53f3e JE |
24 | BUG_ON(ret == -EINVAL); |
25 | if (ret) | |
26 | return ret; | |
27 | ||
28 | /* Not sure if we should loop instead. */ | |
29 | if (retlen != len) | |
30 | return -EIO; | |
31 | ||
32 | return 0; | |
33 | } | |
34 | ||
48d36102 AB |
35 | static int loffs_mtd_write(struct super_block *sb, loff_t ofs, size_t len, |
36 | void *buf) | |
5db53f3e JE |
37 | { |
38 | struct logfs_super *super = logfs_super(sb); | |
39 | struct mtd_info *mtd = super->s_mtd; | |
40 | size_t retlen; | |
41 | loff_t page_start, page_end; | |
42 | int ret; | |
43 | ||
44 | if (super->s_flags & LOGFS_SB_FLAG_RO) | |
45 | return -EROFS; | |
46 | ||
47 | BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs)); | |
48 | BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift); | |
49 | BUG_ON(len > PAGE_CACHE_SIZE); | |
50 | page_start = ofs & PAGE_CACHE_MASK; | |
51 | page_end = PAGE_CACHE_ALIGN(ofs + len) - 1; | |
eda95cbf | 52 | ret = mtd_write(mtd, ofs, len, &retlen, buf); |
5db53f3e JE |
53 | if (ret || (retlen != len)) |
54 | return -EIO; | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
59 | /* | |
60 | * For as long as I can remember (since about 2001) mtd->erase has been an | |
61 | * asynchronous interface lacking the first driver to actually use the | |
62 | * asynchronous properties. So just to prevent the first implementor of such | |
63 | * a thing from breaking logfs in 2350, we do the usual pointless dance to | |
64 | * declare a completion variable and wait for completion before returning | |
48d36102 | 65 | * from logfs_mtd_erase(). What an exercise in futility! |
5db53f3e JE |
66 | */ |
67 | static void logfs_erase_callback(struct erase_info *ei) | |
68 | { | |
69 | complete((struct completion *)ei->priv); | |
70 | } | |
71 | ||
48d36102 AB |
72 | static int logfs_mtd_erase_mapping(struct super_block *sb, loff_t ofs, |
73 | size_t len) | |
5db53f3e JE |
74 | { |
75 | struct logfs_super *super = logfs_super(sb); | |
76 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
77 | struct page *page; | |
78 | pgoff_t index = ofs >> PAGE_SHIFT; | |
79 | ||
80 | for (index = ofs >> PAGE_SHIFT; index < (ofs + len) >> PAGE_SHIFT; index++) { | |
81 | page = find_get_page(mapping, index); | |
82 | if (!page) | |
83 | continue; | |
84 | memset(page_address(page), 0xFF, PAGE_SIZE); | |
85 | page_cache_release(page); | |
86 | } | |
87 | return 0; | |
88 | } | |
89 | ||
48d36102 | 90 | static int logfs_mtd_erase(struct super_block *sb, loff_t ofs, size_t len, |
9421502b | 91 | int ensure_write) |
5db53f3e JE |
92 | { |
93 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
94 | struct erase_info ei; | |
95 | DECLARE_COMPLETION_ONSTACK(complete); | |
96 | int ret; | |
97 | ||
98 | BUG_ON(len % mtd->erasesize); | |
99 | if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) | |
100 | return -EROFS; | |
101 | ||
102 | memset(&ei, 0, sizeof(ei)); | |
103 | ei.mtd = mtd; | |
104 | ei.addr = ofs; | |
105 | ei.len = len; | |
106 | ei.callback = logfs_erase_callback; | |
107 | ei.priv = (long)&complete; | |
7e1f0dc0 | 108 | ret = mtd_erase(mtd, &ei); |
5db53f3e JE |
109 | if (ret) |
110 | return -EIO; | |
111 | ||
112 | wait_for_completion(&complete); | |
113 | if (ei.state != MTD_ERASE_DONE) | |
114 | return -EIO; | |
48d36102 | 115 | return logfs_mtd_erase_mapping(sb, ofs, len); |
5db53f3e JE |
116 | } |
117 | ||
48d36102 | 118 | static void logfs_mtd_sync(struct super_block *sb) |
5db53f3e JE |
119 | { |
120 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
121 | ||
122 | if (mtd->sync) | |
85f2f2a8 | 123 | mtd_sync(mtd); |
5db53f3e JE |
124 | } |
125 | ||
48d36102 | 126 | static int logfs_mtd_readpage(void *_sb, struct page *page) |
5db53f3e JE |
127 | { |
128 | struct super_block *sb = _sb; | |
129 | int err; | |
130 | ||
48d36102 | 131 | err = logfs_mtd_read(sb, page->index << PAGE_SHIFT, PAGE_SIZE, |
5db53f3e | 132 | page_address(page)); |
6f485b41 JE |
133 | if (err == -EUCLEAN || err == -EBADMSG) { |
134 | /* -EBADMSG happens regularly on power failures */ | |
5db53f3e JE |
135 | err = 0; |
136 | /* FIXME: force GC this segment */ | |
137 | } | |
138 | if (err) { | |
139 | ClearPageUptodate(page); | |
140 | SetPageError(page); | |
141 | } else { | |
142 | SetPageUptodate(page); | |
143 | ClearPageError(page); | |
144 | } | |
145 | unlock_page(page); | |
146 | return err; | |
147 | } | |
148 | ||
48d36102 | 149 | static struct page *logfs_mtd_find_first_sb(struct super_block *sb, u64 *ofs) |
5db53f3e JE |
150 | { |
151 | struct logfs_super *super = logfs_super(sb); | |
152 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
48d36102 | 153 | filler_t *filler = logfs_mtd_readpage; |
5db53f3e JE |
154 | struct mtd_info *mtd = super->s_mtd; |
155 | ||
156 | if (!mtd->block_isbad) | |
157 | return NULL; | |
158 | ||
159 | *ofs = 0; | |
160 | while (mtd->block_isbad(mtd, *ofs)) { | |
161 | *ofs += mtd->erasesize; | |
162 | if (*ofs >= mtd->size) | |
163 | return NULL; | |
164 | } | |
165 | BUG_ON(*ofs & ~PAGE_MASK); | |
166 | return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); | |
167 | } | |
168 | ||
48d36102 | 169 | static struct page *logfs_mtd_find_last_sb(struct super_block *sb, u64 *ofs) |
5db53f3e JE |
170 | { |
171 | struct logfs_super *super = logfs_super(sb); | |
172 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
48d36102 | 173 | filler_t *filler = logfs_mtd_readpage; |
5db53f3e JE |
174 | struct mtd_info *mtd = super->s_mtd; |
175 | ||
176 | if (!mtd->block_isbad) | |
177 | return NULL; | |
178 | ||
179 | *ofs = mtd->size - mtd->erasesize; | |
180 | while (mtd->block_isbad(mtd, *ofs)) { | |
181 | *ofs -= mtd->erasesize; | |
182 | if (*ofs <= 0) | |
183 | return NULL; | |
184 | } | |
185 | *ofs = *ofs + mtd->erasesize - 0x1000; | |
186 | BUG_ON(*ofs & ~PAGE_MASK); | |
187 | return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); | |
188 | } | |
189 | ||
48d36102 | 190 | static int __logfs_mtd_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, |
5db53f3e JE |
191 | size_t nr_pages) |
192 | { | |
193 | struct logfs_super *super = logfs_super(sb); | |
194 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
195 | struct page *page; | |
196 | int i, err; | |
197 | ||
198 | for (i = 0; i < nr_pages; i++) { | |
199 | page = find_lock_page(mapping, index + i); | |
200 | BUG_ON(!page); | |
201 | ||
48d36102 AB |
202 | err = loffs_mtd_write(sb, page->index << PAGE_SHIFT, PAGE_SIZE, |
203 | page_address(page)); | |
5db53f3e JE |
204 | unlock_page(page); |
205 | page_cache_release(page); | |
206 | if (err) | |
207 | return err; | |
208 | } | |
209 | return 0; | |
210 | } | |
211 | ||
48d36102 | 212 | static void logfs_mtd_writeseg(struct super_block *sb, u64 ofs, size_t len) |
5db53f3e JE |
213 | { |
214 | struct logfs_super *super = logfs_super(sb); | |
215 | int head; | |
216 | ||
217 | if (super->s_flags & LOGFS_SB_FLAG_RO) | |
218 | return; | |
219 | ||
220 | if (len == 0) { | |
221 | /* This can happen when the object fit perfectly into a | |
222 | * segment, the segment gets written per sync and subsequently | |
223 | * closed. | |
224 | */ | |
225 | return; | |
226 | } | |
227 | head = ofs & (PAGE_SIZE - 1); | |
228 | if (head) { | |
229 | ofs -= head; | |
230 | len += head; | |
231 | } | |
232 | len = PAGE_ALIGN(len); | |
48d36102 | 233 | __logfs_mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); |
5db53f3e JE |
234 | } |
235 | ||
48d36102 | 236 | static void logfs_mtd_put_device(struct logfs_super *s) |
5db53f3e | 237 | { |
e5a0726a | 238 | put_mtd_device(s->s_mtd); |
5db53f3e JE |
239 | } |
240 | ||
48d36102 | 241 | static int logfs_mtd_can_write_buf(struct super_block *sb, u64 ofs) |
6f485b41 JE |
242 | { |
243 | struct logfs_super *super = logfs_super(sb); | |
244 | void *buf; | |
245 | int err; | |
246 | ||
247 | buf = kmalloc(super->s_writesize, GFP_KERNEL); | |
248 | if (!buf) | |
249 | return -ENOMEM; | |
48d36102 | 250 | err = logfs_mtd_read(sb, ofs, super->s_writesize, buf); |
6f485b41 JE |
251 | if (err) |
252 | goto out; | |
253 | if (memchr_inv(buf, 0xff, super->s_writesize)) | |
254 | err = -EIO; | |
255 | kfree(buf); | |
256 | out: | |
257 | return err; | |
258 | } | |
259 | ||
5db53f3e | 260 | static const struct logfs_device_ops mtd_devops = { |
48d36102 AB |
261 | .find_first_sb = logfs_mtd_find_first_sb, |
262 | .find_last_sb = logfs_mtd_find_last_sb, | |
263 | .readpage = logfs_mtd_readpage, | |
264 | .writeseg = logfs_mtd_writeseg, | |
265 | .erase = logfs_mtd_erase, | |
266 | .can_write_buf = logfs_mtd_can_write_buf, | |
267 | .sync = logfs_mtd_sync, | |
268 | .put_device = logfs_mtd_put_device, | |
5db53f3e JE |
269 | }; |
270 | ||
7d945a3a | 271 | int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr) |
5db53f3e | 272 | { |
0d85c799 | 273 | struct mtd_info *mtd = get_mtd_device(NULL, mtdnr); |
7d945a3a | 274 | if (IS_ERR(mtd)) |
ccf31c10 | 275 | return PTR_ERR(mtd); |
0d85c799 AV |
276 | |
277 | s->s_bdev = NULL; | |
278 | s->s_mtd = mtd; | |
279 | s->s_devops = &mtd_devops; | |
7d945a3a | 280 | return 0; |
5db53f3e | 281 | } |