Commit | Line | Data |
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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 | ||
16 | static int mtd_read(struct super_block *sb, loff_t ofs, size_t len, void *buf) | |
17 | { | |
18 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
19 | size_t retlen; | |
20 | int ret; | |
21 | ||
22 | ret = mtd->read(mtd, ofs, len, &retlen, buf); | |
23 | BUG_ON(ret == -EINVAL); | |
24 | if (ret) | |
25 | return ret; | |
26 | ||
27 | /* Not sure if we should loop instead. */ | |
28 | if (retlen != len) | |
29 | return -EIO; | |
30 | ||
31 | return 0; | |
32 | } | |
33 | ||
34 | static int mtd_write(struct super_block *sb, loff_t ofs, size_t len, void *buf) | |
35 | { | |
36 | struct logfs_super *super = logfs_super(sb); | |
37 | struct mtd_info *mtd = super->s_mtd; | |
38 | size_t retlen; | |
39 | loff_t page_start, page_end; | |
40 | int ret; | |
41 | ||
42 | if (super->s_flags & LOGFS_SB_FLAG_RO) | |
43 | return -EROFS; | |
44 | ||
45 | BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs)); | |
46 | BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift); | |
47 | BUG_ON(len > PAGE_CACHE_SIZE); | |
48 | page_start = ofs & PAGE_CACHE_MASK; | |
49 | page_end = PAGE_CACHE_ALIGN(ofs + len) - 1; | |
50 | ret = mtd->write(mtd, ofs, len, &retlen, buf); | |
51 | if (ret || (retlen != len)) | |
52 | return -EIO; | |
53 | ||
54 | return 0; | |
55 | } | |
56 | ||
57 | /* | |
58 | * For as long as I can remember (since about 2001) mtd->erase has been an | |
59 | * asynchronous interface lacking the first driver to actually use the | |
60 | * asynchronous properties. So just to prevent the first implementor of such | |
61 | * a thing from breaking logfs in 2350, we do the usual pointless dance to | |
62 | * declare a completion variable and wait for completion before returning | |
25985edc | 63 | * from mtd_erase(). What an exercise in futility! |
5db53f3e JE |
64 | */ |
65 | static void logfs_erase_callback(struct erase_info *ei) | |
66 | { | |
67 | complete((struct completion *)ei->priv); | |
68 | } | |
69 | ||
70 | static int mtd_erase_mapping(struct super_block *sb, loff_t ofs, size_t len) | |
71 | { | |
72 | struct logfs_super *super = logfs_super(sb); | |
73 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
74 | struct page *page; | |
75 | pgoff_t index = ofs >> PAGE_SHIFT; | |
76 | ||
77 | for (index = ofs >> PAGE_SHIFT; index < (ofs + len) >> PAGE_SHIFT; index++) { | |
78 | page = find_get_page(mapping, index); | |
79 | if (!page) | |
80 | continue; | |
81 | memset(page_address(page), 0xFF, PAGE_SIZE); | |
82 | page_cache_release(page); | |
83 | } | |
84 | return 0; | |
85 | } | |
86 | ||
9421502b JE |
87 | static int mtd_erase(struct super_block *sb, loff_t ofs, size_t len, |
88 | int ensure_write) | |
5db53f3e JE |
89 | { |
90 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
91 | struct erase_info ei; | |
92 | DECLARE_COMPLETION_ONSTACK(complete); | |
93 | int ret; | |
94 | ||
95 | BUG_ON(len % mtd->erasesize); | |
96 | if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) | |
97 | return -EROFS; | |
98 | ||
99 | memset(&ei, 0, sizeof(ei)); | |
100 | ei.mtd = mtd; | |
101 | ei.addr = ofs; | |
102 | ei.len = len; | |
103 | ei.callback = logfs_erase_callback; | |
104 | ei.priv = (long)&complete; | |
105 | ret = mtd->erase(mtd, &ei); | |
106 | if (ret) | |
107 | return -EIO; | |
108 | ||
109 | wait_for_completion(&complete); | |
110 | if (ei.state != MTD_ERASE_DONE) | |
111 | return -EIO; | |
112 | return mtd_erase_mapping(sb, ofs, len); | |
113 | } | |
114 | ||
115 | static void mtd_sync(struct super_block *sb) | |
116 | { | |
117 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
118 | ||
119 | if (mtd->sync) | |
120 | mtd->sync(mtd); | |
121 | } | |
122 | ||
123 | static int mtd_readpage(void *_sb, struct page *page) | |
124 | { | |
125 | struct super_block *sb = _sb; | |
126 | int err; | |
127 | ||
128 | err = mtd_read(sb, page->index << PAGE_SHIFT, PAGE_SIZE, | |
129 | page_address(page)); | |
6f485b41 JE |
130 | if (err == -EUCLEAN || err == -EBADMSG) { |
131 | /* -EBADMSG happens regularly on power failures */ | |
5db53f3e JE |
132 | err = 0; |
133 | /* FIXME: force GC this segment */ | |
134 | } | |
135 | if (err) { | |
136 | ClearPageUptodate(page); | |
137 | SetPageError(page); | |
138 | } else { | |
139 | SetPageUptodate(page); | |
140 | ClearPageError(page); | |
141 | } | |
142 | unlock_page(page); | |
143 | return err; | |
144 | } | |
145 | ||
146 | static struct page *mtd_find_first_sb(struct super_block *sb, u64 *ofs) | |
147 | { | |
148 | struct logfs_super *super = logfs_super(sb); | |
149 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
150 | filler_t *filler = mtd_readpage; | |
151 | struct mtd_info *mtd = super->s_mtd; | |
152 | ||
153 | if (!mtd->block_isbad) | |
154 | return NULL; | |
155 | ||
156 | *ofs = 0; | |
157 | while (mtd->block_isbad(mtd, *ofs)) { | |
158 | *ofs += mtd->erasesize; | |
159 | if (*ofs >= mtd->size) | |
160 | return NULL; | |
161 | } | |
162 | BUG_ON(*ofs & ~PAGE_MASK); | |
163 | return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); | |
164 | } | |
165 | ||
166 | static struct page *mtd_find_last_sb(struct super_block *sb, u64 *ofs) | |
167 | { | |
168 | struct logfs_super *super = logfs_super(sb); | |
169 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
170 | filler_t *filler = mtd_readpage; | |
171 | struct mtd_info *mtd = super->s_mtd; | |
172 | ||
173 | if (!mtd->block_isbad) | |
174 | return NULL; | |
175 | ||
176 | *ofs = mtd->size - mtd->erasesize; | |
177 | while (mtd->block_isbad(mtd, *ofs)) { | |
178 | *ofs -= mtd->erasesize; | |
179 | if (*ofs <= 0) | |
180 | return NULL; | |
181 | } | |
182 | *ofs = *ofs + mtd->erasesize - 0x1000; | |
183 | BUG_ON(*ofs & ~PAGE_MASK); | |
184 | return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); | |
185 | } | |
186 | ||
187 | static int __mtd_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, | |
188 | size_t nr_pages) | |
189 | { | |
190 | struct logfs_super *super = logfs_super(sb); | |
191 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
192 | struct page *page; | |
193 | int i, err; | |
194 | ||
195 | for (i = 0; i < nr_pages; i++) { | |
196 | page = find_lock_page(mapping, index + i); | |
197 | BUG_ON(!page); | |
198 | ||
199 | err = mtd_write(sb, page->index << PAGE_SHIFT, PAGE_SIZE, | |
200 | page_address(page)); | |
201 | unlock_page(page); | |
202 | page_cache_release(page); | |
203 | if (err) | |
204 | return err; | |
205 | } | |
206 | return 0; | |
207 | } | |
208 | ||
209 | static void mtd_writeseg(struct super_block *sb, u64 ofs, size_t len) | |
210 | { | |
211 | struct logfs_super *super = logfs_super(sb); | |
212 | int head; | |
213 | ||
214 | if (super->s_flags & LOGFS_SB_FLAG_RO) | |
215 | return; | |
216 | ||
217 | if (len == 0) { | |
218 | /* This can happen when the object fit perfectly into a | |
219 | * segment, the segment gets written per sync and subsequently | |
220 | * closed. | |
221 | */ | |
222 | return; | |
223 | } | |
224 | head = ofs & (PAGE_SIZE - 1); | |
225 | if (head) { | |
226 | ofs -= head; | |
227 | len += head; | |
228 | } | |
229 | len = PAGE_ALIGN(len); | |
230 | __mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); | |
231 | } | |
232 | ||
e5a0726a | 233 | static void mtd_put_device(struct logfs_super *s) |
5db53f3e | 234 | { |
e5a0726a | 235 | put_mtd_device(s->s_mtd); |
5db53f3e JE |
236 | } |
237 | ||
6f485b41 JE |
238 | static int mtd_can_write_buf(struct super_block *sb, u64 ofs) |
239 | { | |
240 | struct logfs_super *super = logfs_super(sb); | |
241 | void *buf; | |
242 | int err; | |
243 | ||
244 | buf = kmalloc(super->s_writesize, GFP_KERNEL); | |
245 | if (!buf) | |
246 | return -ENOMEM; | |
247 | err = mtd_read(sb, ofs, super->s_writesize, buf); | |
248 | if (err) | |
249 | goto out; | |
250 | if (memchr_inv(buf, 0xff, super->s_writesize)) | |
251 | err = -EIO; | |
252 | kfree(buf); | |
253 | out: | |
254 | return err; | |
255 | } | |
256 | ||
5db53f3e JE |
257 | static const struct logfs_device_ops mtd_devops = { |
258 | .find_first_sb = mtd_find_first_sb, | |
259 | .find_last_sb = mtd_find_last_sb, | |
260 | .readpage = mtd_readpage, | |
261 | .writeseg = mtd_writeseg, | |
262 | .erase = mtd_erase, | |
6f485b41 | 263 | .can_write_buf = mtd_can_write_buf, |
5db53f3e JE |
264 | .sync = mtd_sync, |
265 | .put_device = mtd_put_device, | |
266 | }; | |
267 | ||
7d945a3a | 268 | int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr) |
5db53f3e | 269 | { |
0d85c799 | 270 | struct mtd_info *mtd = get_mtd_device(NULL, mtdnr); |
7d945a3a | 271 | if (IS_ERR(mtd)) |
ccf31c10 | 272 | return PTR_ERR(mtd); |
0d85c799 AV |
273 | |
274 | s->s_bdev = NULL; | |
275 | s->s_mtd = mtd; | |
276 | s->s_devops = &mtd_devops; | |
7d945a3a | 277 | return 0; |
5db53f3e | 278 | } |