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> | |
12 | ||
13 | #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) | |
14 | ||
15 | static int mtd_read(struct super_block *sb, loff_t ofs, size_t len, void *buf) | |
16 | { | |
17 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
18 | size_t retlen; | |
19 | int ret; | |
20 | ||
21 | ret = mtd->read(mtd, ofs, len, &retlen, buf); | |
22 | BUG_ON(ret == -EINVAL); | |
23 | if (ret) | |
24 | return ret; | |
25 | ||
26 | /* Not sure if we should loop instead. */ | |
27 | if (retlen != len) | |
28 | return -EIO; | |
29 | ||
30 | return 0; | |
31 | } | |
32 | ||
33 | static int mtd_write(struct super_block *sb, loff_t ofs, size_t len, void *buf) | |
34 | { | |
35 | struct logfs_super *super = logfs_super(sb); | |
36 | struct mtd_info *mtd = super->s_mtd; | |
37 | size_t retlen; | |
38 | loff_t page_start, page_end; | |
39 | int ret; | |
40 | ||
41 | if (super->s_flags & LOGFS_SB_FLAG_RO) | |
42 | return -EROFS; | |
43 | ||
44 | BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs)); | |
45 | BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift); | |
46 | BUG_ON(len > PAGE_CACHE_SIZE); | |
47 | page_start = ofs & PAGE_CACHE_MASK; | |
48 | page_end = PAGE_CACHE_ALIGN(ofs + len) - 1; | |
49 | ret = mtd->write(mtd, ofs, len, &retlen, buf); | |
50 | if (ret || (retlen != len)) | |
51 | return -EIO; | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
56 | /* | |
57 | * For as long as I can remember (since about 2001) mtd->erase has been an | |
58 | * asynchronous interface lacking the first driver to actually use the | |
59 | * asynchronous properties. So just to prevent the first implementor of such | |
60 | * a thing from breaking logfs in 2350, we do the usual pointless dance to | |
61 | * declare a completion variable and wait for completion before returning | |
62 | * from mtd_erase(). What an excercise in futility! | |
63 | */ | |
64 | static void logfs_erase_callback(struct erase_info *ei) | |
65 | { | |
66 | complete((struct completion *)ei->priv); | |
67 | } | |
68 | ||
69 | static int mtd_erase_mapping(struct super_block *sb, loff_t ofs, size_t len) | |
70 | { | |
71 | struct logfs_super *super = logfs_super(sb); | |
72 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
73 | struct page *page; | |
74 | pgoff_t index = ofs >> PAGE_SHIFT; | |
75 | ||
76 | for (index = ofs >> PAGE_SHIFT; index < (ofs + len) >> PAGE_SHIFT; index++) { | |
77 | page = find_get_page(mapping, index); | |
78 | if (!page) | |
79 | continue; | |
80 | memset(page_address(page), 0xFF, PAGE_SIZE); | |
81 | page_cache_release(page); | |
82 | } | |
83 | return 0; | |
84 | } | |
85 | ||
9421502b JE |
86 | static int mtd_erase(struct super_block *sb, loff_t ofs, size_t len, |
87 | int ensure_write) | |
5db53f3e JE |
88 | { |
89 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
90 | struct erase_info ei; | |
91 | DECLARE_COMPLETION_ONSTACK(complete); | |
92 | int ret; | |
93 | ||
94 | BUG_ON(len % mtd->erasesize); | |
95 | if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) | |
96 | return -EROFS; | |
97 | ||
98 | memset(&ei, 0, sizeof(ei)); | |
99 | ei.mtd = mtd; | |
100 | ei.addr = ofs; | |
101 | ei.len = len; | |
102 | ei.callback = logfs_erase_callback; | |
103 | ei.priv = (long)&complete; | |
104 | ret = mtd->erase(mtd, &ei); | |
105 | if (ret) | |
106 | return -EIO; | |
107 | ||
108 | wait_for_completion(&complete); | |
109 | if (ei.state != MTD_ERASE_DONE) | |
110 | return -EIO; | |
111 | return mtd_erase_mapping(sb, ofs, len); | |
112 | } | |
113 | ||
114 | static void mtd_sync(struct super_block *sb) | |
115 | { | |
116 | struct mtd_info *mtd = logfs_super(sb)->s_mtd; | |
117 | ||
118 | if (mtd->sync) | |
119 | mtd->sync(mtd); | |
120 | } | |
121 | ||
122 | static int mtd_readpage(void *_sb, struct page *page) | |
123 | { | |
124 | struct super_block *sb = _sb; | |
125 | int err; | |
126 | ||
127 | err = mtd_read(sb, page->index << PAGE_SHIFT, PAGE_SIZE, | |
128 | page_address(page)); | |
129 | if (err == -EUCLEAN) { | |
130 | err = 0; | |
131 | /* FIXME: force GC this segment */ | |
132 | } | |
133 | if (err) { | |
134 | ClearPageUptodate(page); | |
135 | SetPageError(page); | |
136 | } else { | |
137 | SetPageUptodate(page); | |
138 | ClearPageError(page); | |
139 | } | |
140 | unlock_page(page); | |
141 | return err; | |
142 | } | |
143 | ||
144 | static struct page *mtd_find_first_sb(struct super_block *sb, u64 *ofs) | |
145 | { | |
146 | struct logfs_super *super = logfs_super(sb); | |
147 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
148 | filler_t *filler = mtd_readpage; | |
149 | struct mtd_info *mtd = super->s_mtd; | |
150 | ||
151 | if (!mtd->block_isbad) | |
152 | return NULL; | |
153 | ||
154 | *ofs = 0; | |
155 | while (mtd->block_isbad(mtd, *ofs)) { | |
156 | *ofs += mtd->erasesize; | |
157 | if (*ofs >= mtd->size) | |
158 | return NULL; | |
159 | } | |
160 | BUG_ON(*ofs & ~PAGE_MASK); | |
161 | return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); | |
162 | } | |
163 | ||
164 | static struct page *mtd_find_last_sb(struct super_block *sb, u64 *ofs) | |
165 | { | |
166 | struct logfs_super *super = logfs_super(sb); | |
167 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
168 | filler_t *filler = mtd_readpage; | |
169 | struct mtd_info *mtd = super->s_mtd; | |
170 | ||
171 | if (!mtd->block_isbad) | |
172 | return NULL; | |
173 | ||
174 | *ofs = mtd->size - mtd->erasesize; | |
175 | while (mtd->block_isbad(mtd, *ofs)) { | |
176 | *ofs -= mtd->erasesize; | |
177 | if (*ofs <= 0) | |
178 | return NULL; | |
179 | } | |
180 | *ofs = *ofs + mtd->erasesize - 0x1000; | |
181 | BUG_ON(*ofs & ~PAGE_MASK); | |
182 | return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); | |
183 | } | |
184 | ||
185 | static int __mtd_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, | |
186 | size_t nr_pages) | |
187 | { | |
188 | struct logfs_super *super = logfs_super(sb); | |
189 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
190 | struct page *page; | |
191 | int i, err; | |
192 | ||
193 | for (i = 0; i < nr_pages; i++) { | |
194 | page = find_lock_page(mapping, index + i); | |
195 | BUG_ON(!page); | |
196 | ||
197 | err = mtd_write(sb, page->index << PAGE_SHIFT, PAGE_SIZE, | |
198 | page_address(page)); | |
199 | unlock_page(page); | |
200 | page_cache_release(page); | |
201 | if (err) | |
202 | return err; | |
203 | } | |
204 | return 0; | |
205 | } | |
206 | ||
207 | static void mtd_writeseg(struct super_block *sb, u64 ofs, size_t len) | |
208 | { | |
209 | struct logfs_super *super = logfs_super(sb); | |
210 | int head; | |
211 | ||
212 | if (super->s_flags & LOGFS_SB_FLAG_RO) | |
213 | return; | |
214 | ||
215 | if (len == 0) { | |
216 | /* This can happen when the object fit perfectly into a | |
217 | * segment, the segment gets written per sync and subsequently | |
218 | * closed. | |
219 | */ | |
220 | return; | |
221 | } | |
222 | head = ofs & (PAGE_SIZE - 1); | |
223 | if (head) { | |
224 | ofs -= head; | |
225 | len += head; | |
226 | } | |
227 | len = PAGE_ALIGN(len); | |
228 | __mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); | |
229 | } | |
230 | ||
231 | static void mtd_put_device(struct super_block *sb) | |
232 | { | |
233 | put_mtd_device(logfs_super(sb)->s_mtd); | |
234 | } | |
235 | ||
236 | static const struct logfs_device_ops mtd_devops = { | |
237 | .find_first_sb = mtd_find_first_sb, | |
238 | .find_last_sb = mtd_find_last_sb, | |
239 | .readpage = mtd_readpage, | |
240 | .writeseg = mtd_writeseg, | |
241 | .erase = mtd_erase, | |
242 | .sync = mtd_sync, | |
243 | .put_device = mtd_put_device, | |
244 | }; | |
245 | ||
246 | int logfs_get_sb_mtd(struct file_system_type *type, int flags, | |
247 | int mtdnr, struct vfsmount *mnt) | |
248 | { | |
249 | struct mtd_info *mtd; | |
250 | const struct logfs_device_ops *devops = &mtd_devops; | |
251 | ||
252 | mtd = get_mtd_device(NULL, mtdnr); | |
253 | return logfs_get_sb_device(type, flags, mtd, NULL, devops, mnt); | |
254 | } |