Commit | Line | Data |
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5db53f3e JE |
1 | /* |
2 | * fs/logfs/dev_bdev.c - Device access methods for block devices | |
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/bio.h> | |
10 | #include <linux/blkdev.h> | |
11 | #include <linux/buffer_head.h> | |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
268bb0ce | 13 | #include <linux/prefetch.h> |
5db53f3e JE |
14 | |
15 | #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) | |
16 | ||
17 | static void request_complete(struct bio *bio, int err) | |
18 | { | |
19 | complete((struct completion *)bio->bi_private); | |
20 | } | |
21 | ||
22 | static int sync_request(struct page *page, struct block_device *bdev, int rw) | |
23 | { | |
24 | struct bio bio; | |
25 | struct bio_vec bio_vec; | |
26 | struct completion complete; | |
27 | ||
28 | bio_init(&bio); | |
cd8bfa9c | 29 | bio.bi_max_vecs = 1; |
5db53f3e JE |
30 | bio.bi_io_vec = &bio_vec; |
31 | bio_vec.bv_page = page; | |
32 | bio_vec.bv_len = PAGE_SIZE; | |
33 | bio_vec.bv_offset = 0; | |
34 | bio.bi_vcnt = 1; | |
5db53f3e JE |
35 | bio.bi_size = PAGE_SIZE; |
36 | bio.bi_bdev = bdev; | |
37 | bio.bi_sector = page->index * (PAGE_SIZE >> 9); | |
38 | init_completion(&complete); | |
39 | bio.bi_private = &complete; | |
40 | bio.bi_end_io = request_complete; | |
41 | ||
42 | submit_bio(rw, &bio); | |
5db53f3e JE |
43 | wait_for_completion(&complete); |
44 | return test_bit(BIO_UPTODATE, &bio.bi_flags) ? 0 : -EIO; | |
45 | } | |
46 | ||
47 | static int bdev_readpage(void *_sb, struct page *page) | |
48 | { | |
49 | struct super_block *sb = _sb; | |
50 | struct block_device *bdev = logfs_super(sb)->s_bdev; | |
51 | int err; | |
52 | ||
53 | err = sync_request(page, bdev, READ); | |
54 | if (err) { | |
55 | ClearPageUptodate(page); | |
56 | SetPageError(page); | |
57 | } else { | |
58 | SetPageUptodate(page); | |
59 | ClearPageError(page); | |
60 | } | |
61 | unlock_page(page); | |
62 | return err; | |
63 | } | |
64 | ||
65 | static DECLARE_WAIT_QUEUE_HEAD(wq); | |
66 | ||
67 | static void writeseg_end_io(struct bio *bio, int err) | |
68 | { | |
69 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
70 | struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; | |
71 | struct super_block *sb = bio->bi_private; | |
72 | struct logfs_super *super = logfs_super(sb); | |
73 | struct page *page; | |
74 | ||
75 | BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ | |
76 | BUG_ON(err); | |
77 | BUG_ON(bio->bi_vcnt == 0); | |
78 | do { | |
79 | page = bvec->bv_page; | |
80 | if (--bvec >= bio->bi_io_vec) | |
81 | prefetchw(&bvec->bv_page->flags); | |
82 | ||
83 | end_page_writeback(page); | |
e07bf553 | 84 | page_cache_release(page); |
5db53f3e JE |
85 | } while (bvec >= bio->bi_io_vec); |
86 | bio_put(bio); | |
87 | if (atomic_dec_and_test(&super->s_pending_writes)) | |
88 | wake_up(&wq); | |
89 | } | |
90 | ||
91 | static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, | |
92 | size_t nr_pages) | |
93 | { | |
94 | struct logfs_super *super = logfs_super(sb); | |
95 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
96 | struct bio *bio; | |
97 | struct page *page; | |
9f0bbd8c | 98 | unsigned int max_pages; |
5db53f3e JE |
99 | int i; |
100 | ||
9f0bbd8c PJ |
101 | max_pages = min(nr_pages, (size_t) bio_get_nr_vecs(super->s_bdev)); |
102 | ||
5db53f3e | 103 | bio = bio_alloc(GFP_NOFS, max_pages); |
59fe27c0 | 104 | BUG_ON(!bio); |
5db53f3e JE |
105 | |
106 | for (i = 0; i < nr_pages; i++) { | |
107 | if (i >= max_pages) { | |
108 | /* Block layer cannot split bios :( */ | |
109 | bio->bi_vcnt = i; | |
5db53f3e JE |
110 | bio->bi_size = i * PAGE_SIZE; |
111 | bio->bi_bdev = super->s_bdev; | |
112 | bio->bi_sector = ofs >> 9; | |
113 | bio->bi_private = sb; | |
114 | bio->bi_end_io = writeseg_end_io; | |
115 | atomic_inc(&super->s_pending_writes); | |
116 | submit_bio(WRITE, bio); | |
117 | ||
118 | ofs += i * PAGE_SIZE; | |
119 | index += i; | |
120 | nr_pages -= i; | |
121 | i = 0; | |
122 | ||
123 | bio = bio_alloc(GFP_NOFS, max_pages); | |
124 | BUG_ON(!bio); | |
125 | } | |
126 | page = find_lock_page(mapping, index + i); | |
127 | BUG_ON(!page); | |
128 | bio->bi_io_vec[i].bv_page = page; | |
129 | bio->bi_io_vec[i].bv_len = PAGE_SIZE; | |
130 | bio->bi_io_vec[i].bv_offset = 0; | |
131 | ||
132 | BUG_ON(PageWriteback(page)); | |
133 | set_page_writeback(page); | |
134 | unlock_page(page); | |
135 | } | |
136 | bio->bi_vcnt = nr_pages; | |
5db53f3e JE |
137 | bio->bi_size = nr_pages * PAGE_SIZE; |
138 | bio->bi_bdev = super->s_bdev; | |
139 | bio->bi_sector = ofs >> 9; | |
140 | bio->bi_private = sb; | |
141 | bio->bi_end_io = writeseg_end_io; | |
142 | atomic_inc(&super->s_pending_writes); | |
143 | submit_bio(WRITE, bio); | |
144 | return 0; | |
145 | } | |
146 | ||
147 | static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len) | |
148 | { | |
149 | struct logfs_super *super = logfs_super(sb); | |
150 | int head; | |
151 | ||
152 | BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO); | |
153 | ||
154 | if (len == 0) { | |
155 | /* This can happen when the object fit perfectly into a | |
156 | * segment, the segment gets written per sync and subsequently | |
157 | * closed. | |
158 | */ | |
159 | return; | |
160 | } | |
161 | head = ofs & (PAGE_SIZE - 1); | |
162 | if (head) { | |
163 | ofs -= head; | |
164 | len += head; | |
165 | } | |
166 | len = PAGE_ALIGN(len); | |
167 | __bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); | |
5db53f3e JE |
168 | } |
169 | ||
9421502b JE |
170 | |
171 | static void erase_end_io(struct bio *bio, int err) | |
172 | { | |
173 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
174 | struct super_block *sb = bio->bi_private; | |
175 | struct logfs_super *super = logfs_super(sb); | |
176 | ||
177 | BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ | |
178 | BUG_ON(err); | |
179 | BUG_ON(bio->bi_vcnt == 0); | |
180 | bio_put(bio); | |
181 | if (atomic_dec_and_test(&super->s_pending_writes)) | |
182 | wake_up(&wq); | |
183 | } | |
184 | ||
185 | static int do_erase(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 bio *bio; | |
9f0bbd8c | 190 | unsigned int max_pages; |
9421502b JE |
191 | int i; |
192 | ||
9f0bbd8c PJ |
193 | max_pages = min(nr_pages, (size_t) bio_get_nr_vecs(super->s_bdev)); |
194 | ||
9421502b | 195 | bio = bio_alloc(GFP_NOFS, max_pages); |
59fe27c0 | 196 | BUG_ON(!bio); |
9421502b JE |
197 | |
198 | for (i = 0; i < nr_pages; i++) { | |
199 | if (i >= max_pages) { | |
200 | /* Block layer cannot split bios :( */ | |
201 | bio->bi_vcnt = i; | |
9421502b JE |
202 | bio->bi_size = i * PAGE_SIZE; |
203 | bio->bi_bdev = super->s_bdev; | |
204 | bio->bi_sector = ofs >> 9; | |
205 | bio->bi_private = sb; | |
206 | bio->bi_end_io = erase_end_io; | |
207 | atomic_inc(&super->s_pending_writes); | |
208 | submit_bio(WRITE, bio); | |
209 | ||
210 | ofs += i * PAGE_SIZE; | |
211 | index += i; | |
212 | nr_pages -= i; | |
213 | i = 0; | |
214 | ||
215 | bio = bio_alloc(GFP_NOFS, max_pages); | |
216 | BUG_ON(!bio); | |
217 | } | |
218 | bio->bi_io_vec[i].bv_page = super->s_erase_page; | |
219 | bio->bi_io_vec[i].bv_len = PAGE_SIZE; | |
220 | bio->bi_io_vec[i].bv_offset = 0; | |
221 | } | |
222 | bio->bi_vcnt = nr_pages; | |
9421502b JE |
223 | bio->bi_size = nr_pages * PAGE_SIZE; |
224 | bio->bi_bdev = super->s_bdev; | |
225 | bio->bi_sector = ofs >> 9; | |
226 | bio->bi_private = sb; | |
227 | bio->bi_end_io = erase_end_io; | |
228 | atomic_inc(&super->s_pending_writes); | |
229 | submit_bio(WRITE, bio); | |
230 | return 0; | |
231 | } | |
232 | ||
233 | static int bdev_erase(struct super_block *sb, loff_t to, size_t len, | |
234 | int ensure_write) | |
5db53f3e JE |
235 | { |
236 | struct logfs_super *super = logfs_super(sb); | |
5db53f3e JE |
237 | |
238 | BUG_ON(to & (PAGE_SIZE - 1)); | |
239 | BUG_ON(len & (PAGE_SIZE - 1)); | |
240 | ||
9421502b | 241 | if (super->s_flags & LOGFS_SB_FLAG_RO) |
5db53f3e JE |
242 | return -EROFS; |
243 | ||
9421502b JE |
244 | if (ensure_write) { |
245 | /* | |
246 | * Object store doesn't care whether erases happen or not. | |
247 | * But for the journal they are required. Otherwise a scan | |
248 | * can find an old commit entry and assume it is the current | |
249 | * one, travelling back in time. | |
250 | */ | |
251 | do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT); | |
5db53f3e | 252 | } |
9421502b | 253 | |
5db53f3e JE |
254 | return 0; |
255 | } | |
256 | ||
257 | static void bdev_sync(struct super_block *sb) | |
258 | { | |
259 | struct logfs_super *super = logfs_super(sb); | |
260 | ||
261 | wait_event(wq, atomic_read(&super->s_pending_writes) == 0); | |
262 | } | |
263 | ||
264 | static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs) | |
265 | { | |
266 | struct logfs_super *super = logfs_super(sb); | |
267 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
268 | filler_t *filler = bdev_readpage; | |
269 | ||
270 | *ofs = 0; | |
271 | return read_cache_page(mapping, 0, filler, sb); | |
272 | } | |
273 | ||
274 | static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs) | |
275 | { | |
276 | struct logfs_super *super = logfs_super(sb); | |
277 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
278 | filler_t *filler = bdev_readpage; | |
279 | u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000; | |
280 | pgoff_t index = pos >> PAGE_SHIFT; | |
281 | ||
282 | *ofs = pos; | |
283 | return read_cache_page(mapping, index, filler, sb); | |
284 | } | |
285 | ||
286 | static int bdev_write_sb(struct super_block *sb, struct page *page) | |
287 | { | |
288 | struct block_device *bdev = logfs_super(sb)->s_bdev; | |
289 | ||
290 | /* Nothing special to do for block devices. */ | |
291 | return sync_request(page, bdev, WRITE); | |
292 | } | |
293 | ||
e5a0726a | 294 | static void bdev_put_device(struct logfs_super *s) |
5db53f3e | 295 | { |
e525fd89 | 296 | blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
5db53f3e JE |
297 | } |
298 | ||
6f485b41 JE |
299 | static int bdev_can_write_buf(struct super_block *sb, u64 ofs) |
300 | { | |
301 | return 0; | |
302 | } | |
303 | ||
5db53f3e JE |
304 | static const struct logfs_device_ops bd_devops = { |
305 | .find_first_sb = bdev_find_first_sb, | |
306 | .find_last_sb = bdev_find_last_sb, | |
307 | .write_sb = bdev_write_sb, | |
308 | .readpage = bdev_readpage, | |
309 | .writeseg = bdev_writeseg, | |
310 | .erase = bdev_erase, | |
6f485b41 | 311 | .can_write_buf = bdev_can_write_buf, |
5db53f3e JE |
312 | .sync = bdev_sync, |
313 | .put_device = bdev_put_device, | |
314 | }; | |
315 | ||
7d945a3a AV |
316 | int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type, |
317 | const char *devname) | |
5db53f3e JE |
318 | { |
319 | struct block_device *bdev; | |
320 | ||
d4d77629 TH |
321 | bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL, |
322 | type); | |
7d945a3a | 323 | if (IS_ERR(bdev)) |
5db53f3e JE |
324 | return PTR_ERR(bdev); |
325 | ||
326 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { | |
327 | int mtdnr = MINOR(bdev->bd_dev); | |
e525fd89 | 328 | blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
7d945a3a | 329 | return logfs_get_sb_mtd(p, mtdnr); |
5db53f3e JE |
330 | } |
331 | ||
0d85c799 AV |
332 | p->s_bdev = bdev; |
333 | p->s_mtd = NULL; | |
334 | p->s_devops = &bd_devops; | |
7d945a3a | 335 | return 0; |
5db53f3e | 336 | } |