Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 12 | #include <linux/gfp.h> |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 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); |
Joern Engel | e07bf55 | 2010-03-17 15:29:38 +0100 | [diff] [blame] | 84 | page_cache_release(page); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 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 | |
Joern Engel | 59fe27c | 2010-03-17 13:47:45 +0100 | [diff] [blame] | 102 | if (max_pages > BIO_MAX_PAGES) |
| 103 | max_pages = BIO_MAX_PAGES; |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 104 | bio = bio_alloc(GFP_NOFS, max_pages); |
Joern Engel | 59fe27c | 2010-03-17 13:47:45 +0100 | [diff] [blame] | 105 | BUG_ON(!bio); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 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 | |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 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) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 191 | { |
| 192 | struct logfs_super *super = logfs_super(sb); |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 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 | |
Joern Engel | 59fe27c | 2010-03-17 13:47:45 +0100 | [diff] [blame] | 198 | if (max_pages > BIO_MAX_PAGES) |
| 199 | max_pages = BIO_MAX_PAGES; |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 200 | bio = bio_alloc(GFP_NOFS, max_pages); |
Joern Engel | 59fe27c | 2010-03-17 13:47:45 +0100 | [diff] [blame] | 201 | BUG_ON(!bio); |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 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) |
| 242 | { |
| 243 | struct logfs_super *super = logfs_super(sb); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 244 | |
| 245 | BUG_ON(to & (PAGE_SIZE - 1)); |
| 246 | BUG_ON(len & (PAGE_SIZE - 1)); |
| 247 | |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 248 | if (super->s_flags & LOGFS_SB_FLAG_RO) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 249 | return -EROFS; |
| 250 | |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 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); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 259 | } |
Joern Engel | 9421502 | 2010-03-04 21:30:58 +0100 | [diff] [blame] | 260 | |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 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 | |
Al Viro | e5a0726 | 2010-07-26 12:06:00 +0400 | [diff] [blame] | 301 | static void bdev_put_device(struct logfs_super *s) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 302 | { |
Al Viro | e5a0726 | 2010-07-26 12:06:00 +0400 | [diff] [blame] | 303 | close_bdev_exclusive(s->s_bdev, FMODE_READ|FMODE_WRITE); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 304 | } |
| 305 | |
Joern Engel | 6f485b41 | 2010-05-07 19:38:40 +0200 | [diff] [blame] | 306 | static int bdev_can_write_buf(struct super_block *sb, u64 ofs) |
| 307 | { |
| 308 | return 0; |
| 309 | } |
| 310 | |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 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, |
Joern Engel | 6f485b41 | 2010-05-07 19:38:40 +0200 | [diff] [blame] | 318 | .can_write_buf = bdev_can_write_buf, |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 319 | .sync = bdev_sync, |
| 320 | .put_device = bdev_put_device, |
| 321 | }; |
| 322 | |
Al Viro | 7d945a3 | 2010-07-26 11:53:30 +0400 | [diff] [blame] | 323 | int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type, |
| 324 | const char *devname) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 325 | { |
| 326 | struct block_device *bdev; |
| 327 | |
| 328 | bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type); |
Al Viro | 7d945a3 | 2010-07-26 11:53:30 +0400 | [diff] [blame] | 329 | if (IS_ERR(bdev)) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 330 | return PTR_ERR(bdev); |
| 331 | |
| 332 | if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { |
| 333 | int mtdnr = MINOR(bdev->bd_dev); |
| 334 | close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE); |
Al Viro | 7d945a3 | 2010-07-26 11:53:30 +0400 | [diff] [blame] | 335 | return logfs_get_sb_mtd(p, mtdnr); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 336 | } |
| 337 | |
Al Viro | 0d85c79 | 2010-07-26 11:33:39 +0400 | [diff] [blame] | 338 | p->s_bdev = bdev; |
| 339 | p->s_mtd = NULL; |
| 340 | p->s_devops = &bd_devops; |
Al Viro | 7d945a3 | 2010-07-26 11:53:30 +0400 | [diff] [blame] | 341 | return 0; |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 342 | } |