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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> |
5db53f3e JE |
13 | |
14 | #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) | |
15 | ||
16 | static void request_complete(struct bio *bio, int err) | |
17 | { | |
18 | complete((struct completion *)bio->bi_private); | |
19 | } | |
20 | ||
21 | static int sync_request(struct page *page, struct block_device *bdev, int rw) | |
22 | { | |
23 | struct bio bio; | |
24 | struct bio_vec bio_vec; | |
25 | struct completion complete; | |
26 | ||
27 | bio_init(&bio); | |
28 | bio.bi_io_vec = &bio_vec; | |
29 | bio_vec.bv_page = page; | |
30 | bio_vec.bv_len = PAGE_SIZE; | |
31 | bio_vec.bv_offset = 0; | |
32 | bio.bi_vcnt = 1; | |
33 | bio.bi_idx = 0; | |
34 | bio.bi_size = PAGE_SIZE; | |
35 | bio.bi_bdev = bdev; | |
36 | bio.bi_sector = page->index * (PAGE_SIZE >> 9); | |
37 | init_completion(&complete); | |
38 | bio.bi_private = &complete; | |
39 | bio.bi_end_io = request_complete; | |
40 | ||
41 | submit_bio(rw, &bio); | |
42 | generic_unplug_device(bdev_get_queue(bdev)); | |
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; | |
98 | struct request_queue *q = bdev_get_queue(sb->s_bdev); | |
99 | unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9); | |
100 | int i; | |
101 | ||
59fe27c0 JE |
102 | if (max_pages > BIO_MAX_PAGES) |
103 | max_pages = BIO_MAX_PAGES; | |
5db53f3e | 104 | bio = bio_alloc(GFP_NOFS, max_pages); |
59fe27c0 | 105 | BUG_ON(!bio); |
5db53f3e JE |
106 | |
107 | for (i = 0; i < nr_pages; i++) { | |
108 | if (i >= max_pages) { | |
109 | /* Block layer cannot split bios :( */ | |
110 | bio->bi_vcnt = i; | |
111 | bio->bi_idx = 0; | |
112 | bio->bi_size = i * PAGE_SIZE; | |
113 | bio->bi_bdev = super->s_bdev; | |
114 | bio->bi_sector = ofs >> 9; | |
115 | bio->bi_private = sb; | |
116 | bio->bi_end_io = writeseg_end_io; | |
117 | atomic_inc(&super->s_pending_writes); | |
118 | submit_bio(WRITE, bio); | |
119 | ||
120 | ofs += i * PAGE_SIZE; | |
121 | index += i; | |
122 | nr_pages -= i; | |
123 | i = 0; | |
124 | ||
125 | bio = bio_alloc(GFP_NOFS, max_pages); | |
126 | BUG_ON(!bio); | |
127 | } | |
128 | page = find_lock_page(mapping, index + i); | |
129 | BUG_ON(!page); | |
130 | bio->bi_io_vec[i].bv_page = page; | |
131 | bio->bi_io_vec[i].bv_len = PAGE_SIZE; | |
132 | bio->bi_io_vec[i].bv_offset = 0; | |
133 | ||
134 | BUG_ON(PageWriteback(page)); | |
135 | set_page_writeback(page); | |
136 | unlock_page(page); | |
137 | } | |
138 | bio->bi_vcnt = nr_pages; | |
139 | bio->bi_idx = 0; | |
140 | bio->bi_size = nr_pages * PAGE_SIZE; | |
141 | bio->bi_bdev = super->s_bdev; | |
142 | bio->bi_sector = ofs >> 9; | |
143 | bio->bi_private = sb; | |
144 | bio->bi_end_io = writeseg_end_io; | |
145 | atomic_inc(&super->s_pending_writes); | |
146 | submit_bio(WRITE, bio); | |
147 | return 0; | |
148 | } | |
149 | ||
150 | static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len) | |
151 | { | |
152 | struct logfs_super *super = logfs_super(sb); | |
153 | int head; | |
154 | ||
155 | BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO); | |
156 | ||
157 | if (len == 0) { | |
158 | /* This can happen when the object fit perfectly into a | |
159 | * segment, the segment gets written per sync and subsequently | |
160 | * closed. | |
161 | */ | |
162 | return; | |
163 | } | |
164 | head = ofs & (PAGE_SIZE - 1); | |
165 | if (head) { | |
166 | ofs -= head; | |
167 | len += head; | |
168 | } | |
169 | len = PAGE_ALIGN(len); | |
170 | __bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); | |
171 | generic_unplug_device(bdev_get_queue(logfs_super(sb)->s_bdev)); | |
172 | } | |
173 | ||
9421502b JE |
174 | |
175 | static void erase_end_io(struct bio *bio, int err) | |
176 | { | |
177 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
178 | struct super_block *sb = bio->bi_private; | |
179 | struct logfs_super *super = logfs_super(sb); | |
180 | ||
181 | BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ | |
182 | BUG_ON(err); | |
183 | BUG_ON(bio->bi_vcnt == 0); | |
184 | bio_put(bio); | |
185 | if (atomic_dec_and_test(&super->s_pending_writes)) | |
186 | wake_up(&wq); | |
187 | } | |
188 | ||
189 | static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index, | |
190 | size_t nr_pages) | |
191 | { | |
192 | struct logfs_super *super = logfs_super(sb); | |
193 | struct bio *bio; | |
194 | struct request_queue *q = bdev_get_queue(sb->s_bdev); | |
195 | unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9); | |
196 | int i; | |
197 | ||
59fe27c0 JE |
198 | if (max_pages > BIO_MAX_PAGES) |
199 | max_pages = BIO_MAX_PAGES; | |
9421502b | 200 | bio = bio_alloc(GFP_NOFS, max_pages); |
59fe27c0 | 201 | BUG_ON(!bio); |
9421502b JE |
202 | |
203 | for (i = 0; i < nr_pages; i++) { | |
204 | if (i >= max_pages) { | |
205 | /* Block layer cannot split bios :( */ | |
206 | bio->bi_vcnt = i; | |
207 | bio->bi_idx = 0; | |
208 | bio->bi_size = i * PAGE_SIZE; | |
209 | bio->bi_bdev = super->s_bdev; | |
210 | bio->bi_sector = ofs >> 9; | |
211 | bio->bi_private = sb; | |
212 | bio->bi_end_io = erase_end_io; | |
213 | atomic_inc(&super->s_pending_writes); | |
214 | submit_bio(WRITE, bio); | |
215 | ||
216 | ofs += i * PAGE_SIZE; | |
217 | index += i; | |
218 | nr_pages -= i; | |
219 | i = 0; | |
220 | ||
221 | bio = bio_alloc(GFP_NOFS, max_pages); | |
222 | BUG_ON(!bio); | |
223 | } | |
224 | bio->bi_io_vec[i].bv_page = super->s_erase_page; | |
225 | bio->bi_io_vec[i].bv_len = PAGE_SIZE; | |
226 | bio->bi_io_vec[i].bv_offset = 0; | |
227 | } | |
228 | bio->bi_vcnt = nr_pages; | |
229 | bio->bi_idx = 0; | |
230 | bio->bi_size = nr_pages * PAGE_SIZE; | |
231 | bio->bi_bdev = super->s_bdev; | |
232 | bio->bi_sector = ofs >> 9; | |
233 | bio->bi_private = sb; | |
234 | bio->bi_end_io = erase_end_io; | |
235 | atomic_inc(&super->s_pending_writes); | |
236 | submit_bio(WRITE, bio); | |
237 | return 0; | |
238 | } | |
239 | ||
240 | static int bdev_erase(struct super_block *sb, loff_t to, size_t len, | |
241 | int ensure_write) | |
5db53f3e JE |
242 | { |
243 | struct logfs_super *super = logfs_super(sb); | |
5db53f3e JE |
244 | |
245 | BUG_ON(to & (PAGE_SIZE - 1)); | |
246 | BUG_ON(len & (PAGE_SIZE - 1)); | |
247 | ||
9421502b | 248 | if (super->s_flags & LOGFS_SB_FLAG_RO) |
5db53f3e JE |
249 | return -EROFS; |
250 | ||
9421502b JE |
251 | if (ensure_write) { |
252 | /* | |
253 | * Object store doesn't care whether erases happen or not. | |
254 | * But for the journal they are required. Otherwise a scan | |
255 | * can find an old commit entry and assume it is the current | |
256 | * one, travelling back in time. | |
257 | */ | |
258 | do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT); | |
5db53f3e | 259 | } |
9421502b | 260 | |
5db53f3e JE |
261 | return 0; |
262 | } | |
263 | ||
264 | static void bdev_sync(struct super_block *sb) | |
265 | { | |
266 | struct logfs_super *super = logfs_super(sb); | |
267 | ||
268 | wait_event(wq, atomic_read(&super->s_pending_writes) == 0); | |
269 | } | |
270 | ||
271 | static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs) | |
272 | { | |
273 | struct logfs_super *super = logfs_super(sb); | |
274 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
275 | filler_t *filler = bdev_readpage; | |
276 | ||
277 | *ofs = 0; | |
278 | return read_cache_page(mapping, 0, filler, sb); | |
279 | } | |
280 | ||
281 | static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs) | |
282 | { | |
283 | struct logfs_super *super = logfs_super(sb); | |
284 | struct address_space *mapping = super->s_mapping_inode->i_mapping; | |
285 | filler_t *filler = bdev_readpage; | |
286 | u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000; | |
287 | pgoff_t index = pos >> PAGE_SHIFT; | |
288 | ||
289 | *ofs = pos; | |
290 | return read_cache_page(mapping, index, filler, sb); | |
291 | } | |
292 | ||
293 | static int bdev_write_sb(struct super_block *sb, struct page *page) | |
294 | { | |
295 | struct block_device *bdev = logfs_super(sb)->s_bdev; | |
296 | ||
297 | /* Nothing special to do for block devices. */ | |
298 | return sync_request(page, bdev, WRITE); | |
299 | } | |
300 | ||
e5a0726a | 301 | static void bdev_put_device(struct logfs_super *s) |
5db53f3e | 302 | { |
e525fd89 | 303 | blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
5db53f3e JE |
304 | } |
305 | ||
6f485b41 JE |
306 | static int bdev_can_write_buf(struct super_block *sb, u64 ofs) |
307 | { | |
308 | return 0; | |
309 | } | |
310 | ||
5db53f3e JE |
311 | static const struct logfs_device_ops bd_devops = { |
312 | .find_first_sb = bdev_find_first_sb, | |
313 | .find_last_sb = bdev_find_last_sb, | |
314 | .write_sb = bdev_write_sb, | |
315 | .readpage = bdev_readpage, | |
316 | .writeseg = bdev_writeseg, | |
317 | .erase = bdev_erase, | |
6f485b41 | 318 | .can_write_buf = bdev_can_write_buf, |
5db53f3e JE |
319 | .sync = bdev_sync, |
320 | .put_device = bdev_put_device, | |
321 | }; | |
322 | ||
7d945a3a AV |
323 | int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type, |
324 | const char *devname) | |
5db53f3e JE |
325 | { |
326 | struct block_device *bdev; | |
327 | ||
d4d77629 TH |
328 | bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL, |
329 | type); | |
7d945a3a | 330 | if (IS_ERR(bdev)) |
5db53f3e JE |
331 | return PTR_ERR(bdev); |
332 | ||
333 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { | |
334 | int mtdnr = MINOR(bdev->bd_dev); | |
e525fd89 | 335 | blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
7d945a3a | 336 | return logfs_get_sb_mtd(p, mtdnr); |
5db53f3e JE |
337 | } |
338 | ||
0d85c799 AV |
339 | p->s_bdev = bdev; |
340 | p->s_mtd = NULL; | |
341 | p->s_devops = &bd_devops; | |
7d945a3a | 342 | return 0; |
5db53f3e | 343 | } |