Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 1 | /* |
| 2 | * page.c - buffer/page management specific to NILFS |
| 3 | * |
| 4 | * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | * |
| 20 | * Written by Ryusuke Konishi <ryusuke@osrg.net>, |
| 21 | * Seiji Kihara <kihara@osrg.net>. |
| 22 | */ |
| 23 | |
| 24 | #include <linux/pagemap.h> |
| 25 | #include <linux/writeback.h> |
| 26 | #include <linux/swap.h> |
| 27 | #include <linux/bitops.h> |
| 28 | #include <linux/page-flags.h> |
| 29 | #include <linux/list.h> |
| 30 | #include <linux/highmem.h> |
| 31 | #include <linux/pagevec.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 32 | #include <linux/gfp.h> |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 33 | #include "nilfs.h" |
| 34 | #include "page.h" |
| 35 | #include "mdt.h" |
| 36 | |
| 37 | |
| 38 | #define NILFS_BUFFER_INHERENT_BITS \ |
| 39 | ((1UL << BH_Uptodate) | (1UL << BH_Mapped) | (1UL << BH_NILFS_Node) | \ |
Ryusuke Konishi | 4e13e66 | 2010-07-18 10:42:25 +0900 | [diff] [blame] | 40 | (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Allocated) | \ |
| 41 | (1UL << BH_NILFS_Checked)) |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 42 | |
| 43 | static struct buffer_head * |
| 44 | __nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index, |
| 45 | int blkbits, unsigned long b_state) |
| 46 | |
| 47 | { |
| 48 | unsigned long first_block; |
| 49 | struct buffer_head *bh; |
| 50 | |
| 51 | if (!page_has_buffers(page)) |
| 52 | create_empty_buffers(page, 1 << blkbits, b_state); |
| 53 | |
| 54 | first_block = (unsigned long)index << (PAGE_CACHE_SHIFT - blkbits); |
| 55 | bh = nilfs_page_get_nth_block(page, block - first_block); |
| 56 | |
| 57 | touch_buffer(bh); |
| 58 | wait_on_buffer(bh); |
| 59 | return bh; |
| 60 | } |
| 61 | |
| 62 | /* |
| 63 | * Since the page cache of B-tree node pages or data page cache of pseudo |
| 64 | * inodes does not have a valid mapping->host pointer, calling |
| 65 | * mark_buffer_dirty() for their buffers causes a NULL pointer dereference; |
| 66 | * it calls __mark_inode_dirty(NULL) through __set_page_dirty(). |
| 67 | * To avoid this problem, the old style mark_buffer_dirty() is used instead. |
| 68 | */ |
| 69 | void nilfs_mark_buffer_dirty(struct buffer_head *bh) |
| 70 | { |
| 71 | if (!buffer_dirty(bh) && !test_set_buffer_dirty(bh)) |
| 72 | __set_page_dirty_nobuffers(bh->b_page); |
| 73 | } |
| 74 | |
| 75 | struct buffer_head *nilfs_grab_buffer(struct inode *inode, |
| 76 | struct address_space *mapping, |
| 77 | unsigned long blkoff, |
| 78 | unsigned long b_state) |
| 79 | { |
| 80 | int blkbits = inode->i_blkbits; |
| 81 | pgoff_t index = blkoff >> (PAGE_CACHE_SHIFT - blkbits); |
Ryusuke Konishi | c1c1d7092 | 2010-08-29 12:44:56 +0900 | [diff] [blame] | 82 | struct page *page; |
| 83 | struct buffer_head *bh; |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 84 | |
| 85 | page = grab_cache_page(mapping, index); |
| 86 | if (unlikely(!page)) |
| 87 | return NULL; |
| 88 | |
| 89 | bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state); |
| 90 | if (unlikely(!bh)) { |
| 91 | unlock_page(page); |
| 92 | page_cache_release(page); |
| 93 | return NULL; |
| 94 | } |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 95 | return bh; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * nilfs_forget_buffer - discard dirty state |
| 100 | * @inode: owner inode of the buffer |
| 101 | * @bh: buffer head of the buffer to be discarded |
| 102 | */ |
| 103 | void nilfs_forget_buffer(struct buffer_head *bh) |
| 104 | { |
| 105 | struct page *page = bh->b_page; |
| 106 | |
| 107 | lock_buffer(bh); |
| 108 | clear_buffer_nilfs_volatile(bh); |
Ryusuke Konishi | 4e13e66 | 2010-07-18 10:42:25 +0900 | [diff] [blame] | 109 | clear_buffer_nilfs_checked(bh); |
Ryusuke Konishi | b1f6a4f | 2010-08-31 11:40:34 +0900 | [diff] [blame] | 110 | clear_buffer_nilfs_redirected(bh); |
Ryusuke Konishi | 8433823 | 2009-05-05 21:52:06 +0900 | [diff] [blame] | 111 | clear_buffer_dirty(bh); |
| 112 | if (nilfs_page_buffers_clean(page)) |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 113 | __nilfs_clear_page_dirty(page); |
| 114 | |
| 115 | clear_buffer_uptodate(bh); |
| 116 | clear_buffer_mapped(bh); |
| 117 | bh->b_blocknr = -1; |
| 118 | ClearPageUptodate(page); |
| 119 | ClearPageMappedToDisk(page); |
| 120 | unlock_buffer(bh); |
| 121 | brelse(bh); |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * nilfs_copy_buffer -- copy buffer data and flags |
| 126 | * @dbh: destination buffer |
| 127 | * @sbh: source buffer |
| 128 | */ |
| 129 | void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh) |
| 130 | { |
| 131 | void *kaddr0, *kaddr1; |
| 132 | unsigned long bits; |
| 133 | struct page *spage = sbh->b_page, *dpage = dbh->b_page; |
| 134 | struct buffer_head *bh; |
| 135 | |
| 136 | kaddr0 = kmap_atomic(spage, KM_USER0); |
| 137 | kaddr1 = kmap_atomic(dpage, KM_USER1); |
| 138 | memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size); |
| 139 | kunmap_atomic(kaddr1, KM_USER1); |
| 140 | kunmap_atomic(kaddr0, KM_USER0); |
| 141 | |
| 142 | dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS; |
| 143 | dbh->b_blocknr = sbh->b_blocknr; |
| 144 | dbh->b_bdev = sbh->b_bdev; |
| 145 | |
| 146 | bh = dbh; |
| 147 | bits = sbh->b_state & ((1UL << BH_Uptodate) | (1UL << BH_Mapped)); |
| 148 | while ((bh = bh->b_this_page) != dbh) { |
| 149 | lock_buffer(bh); |
| 150 | bits &= bh->b_state; |
| 151 | unlock_buffer(bh); |
| 152 | } |
| 153 | if (bits & (1UL << BH_Uptodate)) |
| 154 | SetPageUptodate(dpage); |
| 155 | else |
| 156 | ClearPageUptodate(dpage); |
| 157 | if (bits & (1UL << BH_Mapped)) |
| 158 | SetPageMappedToDisk(dpage); |
| 159 | else |
| 160 | ClearPageMappedToDisk(dpage); |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * nilfs_page_buffers_clean - check if a page has dirty buffers or not. |
| 165 | * @page: page to be checked |
| 166 | * |
| 167 | * nilfs_page_buffers_clean() returns zero if the page has dirty buffers. |
| 168 | * Otherwise, it returns non-zero value. |
| 169 | */ |
| 170 | int nilfs_page_buffers_clean(struct page *page) |
| 171 | { |
| 172 | struct buffer_head *bh, *head; |
| 173 | |
| 174 | bh = head = page_buffers(page); |
| 175 | do { |
| 176 | if (buffer_dirty(bh)) |
| 177 | return 0; |
| 178 | bh = bh->b_this_page; |
| 179 | } while (bh != head); |
| 180 | return 1; |
| 181 | } |
| 182 | |
| 183 | void nilfs_page_bug(struct page *page) |
| 184 | { |
| 185 | struct address_space *m; |
| 186 | unsigned long ino = 0; |
| 187 | |
| 188 | if (unlikely(!page)) { |
| 189 | printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n"); |
| 190 | return; |
| 191 | } |
| 192 | |
| 193 | m = page->mapping; |
| 194 | if (m) { |
| 195 | struct inode *inode = NILFS_AS_I(m); |
| 196 | if (inode != NULL) |
| 197 | ino = inode->i_ino; |
| 198 | } |
| 199 | printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx " |
| 200 | "mapping=%p ino=%lu\n", |
| 201 | page, atomic_read(&page->_count), |
| 202 | (unsigned long long)page->index, page->flags, m, ino); |
| 203 | |
| 204 | if (page_has_buffers(page)) { |
| 205 | struct buffer_head *bh, *head; |
| 206 | int i = 0; |
| 207 | |
| 208 | bh = head = page_buffers(page); |
| 209 | do { |
| 210 | printk(KERN_CRIT |
| 211 | " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n", |
| 212 | i++, bh, atomic_read(&bh->b_count), |
| 213 | (unsigned long long)bh->b_blocknr, bh->b_state); |
| 214 | bh = bh->b_this_page; |
| 215 | } while (bh != head); |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * nilfs_alloc_private_page - allocate a private page with buffer heads |
| 221 | * |
| 222 | * Return Value: On success, a pointer to the allocated page is returned. |
| 223 | * On error, NULL is returned. |
| 224 | */ |
| 225 | struct page *nilfs_alloc_private_page(struct block_device *bdev, int size, |
| 226 | unsigned long state) |
| 227 | { |
| 228 | struct buffer_head *bh, *head, *tail; |
| 229 | struct page *page; |
| 230 | |
| 231 | page = alloc_page(GFP_NOFS); /* page_count of the returned page is 1 */ |
| 232 | if (unlikely(!page)) |
| 233 | return NULL; |
| 234 | |
| 235 | lock_page(page); |
| 236 | head = alloc_page_buffers(page, size, 0); |
| 237 | if (unlikely(!head)) { |
| 238 | unlock_page(page); |
| 239 | __free_page(page); |
| 240 | return NULL; |
| 241 | } |
| 242 | |
| 243 | bh = head; |
| 244 | do { |
| 245 | bh->b_state = (1UL << BH_NILFS_Allocated) | state; |
| 246 | tail = bh; |
| 247 | bh->b_bdev = bdev; |
| 248 | bh = bh->b_this_page; |
| 249 | } while (bh); |
| 250 | |
| 251 | tail->b_this_page = head; |
| 252 | attach_page_buffers(page, head); |
| 253 | |
| 254 | return page; |
| 255 | } |
| 256 | |
| 257 | void nilfs_free_private_page(struct page *page) |
| 258 | { |
| 259 | BUG_ON(!PageLocked(page)); |
| 260 | BUG_ON(page->mapping); |
| 261 | |
| 262 | if (page_has_buffers(page) && !try_to_free_buffers(page)) |
| 263 | NILFS_PAGE_BUG(page, "failed to free page"); |
| 264 | |
| 265 | unlock_page(page); |
| 266 | __free_page(page); |
| 267 | } |
| 268 | |
| 269 | /** |
| 270 | * nilfs_copy_page -- copy the page with buffers |
| 271 | * @dst: destination page |
| 272 | * @src: source page |
| 273 | * @copy_dirty: flag whether to copy dirty states on the page's buffer heads. |
| 274 | * |
Ryusuke Konishi | 7a65004 | 2010-03-14 03:32:40 +0900 | [diff] [blame] | 275 | * This function is for both data pages and btnode pages. The dirty flag |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 276 | * should be treated by caller. The page must not be under i/o. |
| 277 | * Both src and dst page must be locked |
| 278 | */ |
| 279 | static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty) |
| 280 | { |
| 281 | struct buffer_head *dbh, *dbufs, *sbh, *sbufs; |
| 282 | unsigned long mask = NILFS_BUFFER_INHERENT_BITS; |
| 283 | |
| 284 | BUG_ON(PageWriteback(dst)); |
| 285 | |
| 286 | sbh = sbufs = page_buffers(src); |
| 287 | if (!page_has_buffers(dst)) |
| 288 | create_empty_buffers(dst, sbh->b_size, 0); |
| 289 | |
| 290 | if (copy_dirty) |
| 291 | mask |= (1UL << BH_Dirty); |
| 292 | |
| 293 | dbh = dbufs = page_buffers(dst); |
| 294 | do { |
| 295 | lock_buffer(sbh); |
| 296 | lock_buffer(dbh); |
| 297 | dbh->b_state = sbh->b_state & mask; |
| 298 | dbh->b_blocknr = sbh->b_blocknr; |
| 299 | dbh->b_bdev = sbh->b_bdev; |
| 300 | sbh = sbh->b_this_page; |
| 301 | dbh = dbh->b_this_page; |
| 302 | } while (dbh != dbufs); |
| 303 | |
| 304 | copy_highpage(dst, src); |
| 305 | |
| 306 | if (PageUptodate(src) && !PageUptodate(dst)) |
| 307 | SetPageUptodate(dst); |
| 308 | else if (!PageUptodate(src) && PageUptodate(dst)) |
| 309 | ClearPageUptodate(dst); |
| 310 | if (PageMappedToDisk(src) && !PageMappedToDisk(dst)) |
| 311 | SetPageMappedToDisk(dst); |
| 312 | else if (!PageMappedToDisk(src) && PageMappedToDisk(dst)) |
| 313 | ClearPageMappedToDisk(dst); |
| 314 | |
| 315 | do { |
| 316 | unlock_buffer(sbh); |
| 317 | unlock_buffer(dbh); |
| 318 | sbh = sbh->b_this_page; |
| 319 | dbh = dbh->b_this_page; |
| 320 | } while (dbh != dbufs); |
| 321 | } |
| 322 | |
| 323 | int nilfs_copy_dirty_pages(struct address_space *dmap, |
| 324 | struct address_space *smap) |
| 325 | { |
| 326 | struct pagevec pvec; |
| 327 | unsigned int i; |
| 328 | pgoff_t index = 0; |
| 329 | int err = 0; |
| 330 | |
| 331 | pagevec_init(&pvec, 0); |
| 332 | repeat: |
| 333 | if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY, |
| 334 | PAGEVEC_SIZE)) |
| 335 | return 0; |
| 336 | |
| 337 | for (i = 0; i < pagevec_count(&pvec); i++) { |
| 338 | struct page *page = pvec.pages[i], *dpage; |
| 339 | |
| 340 | lock_page(page); |
| 341 | if (unlikely(!PageDirty(page))) |
| 342 | NILFS_PAGE_BUG(page, "inconsistent dirty state"); |
| 343 | |
| 344 | dpage = grab_cache_page(dmap, page->index); |
| 345 | if (unlikely(!dpage)) { |
| 346 | /* No empty page is added to the page cache */ |
| 347 | err = -ENOMEM; |
| 348 | unlock_page(page); |
| 349 | break; |
| 350 | } |
| 351 | if (unlikely(!page_has_buffers(page))) |
| 352 | NILFS_PAGE_BUG(page, |
| 353 | "found empty page in dat page cache"); |
| 354 | |
| 355 | nilfs_copy_page(dpage, page, 1); |
| 356 | __set_page_dirty_nobuffers(dpage); |
| 357 | |
| 358 | unlock_page(dpage); |
| 359 | page_cache_release(dpage); |
| 360 | unlock_page(page); |
| 361 | } |
| 362 | pagevec_release(&pvec); |
| 363 | cond_resched(); |
| 364 | |
| 365 | if (likely(!err)) |
| 366 | goto repeat; |
| 367 | return err; |
| 368 | } |
| 369 | |
| 370 | /** |
Ryusuke Konishi | 7a65004 | 2010-03-14 03:32:40 +0900 | [diff] [blame] | 371 | * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 372 | * @dmap: destination page cache |
| 373 | * @smap: source page cache |
| 374 | * |
| 375 | * No pages must no be added to the cache during this process. |
| 376 | * This must be ensured by the caller. |
| 377 | */ |
| 378 | void nilfs_copy_back_pages(struct address_space *dmap, |
| 379 | struct address_space *smap) |
| 380 | { |
| 381 | struct pagevec pvec; |
| 382 | unsigned int i, n; |
| 383 | pgoff_t index = 0; |
| 384 | int err; |
| 385 | |
| 386 | pagevec_init(&pvec, 0); |
| 387 | repeat: |
| 388 | n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE); |
| 389 | if (!n) |
| 390 | return; |
| 391 | index = pvec.pages[n - 1]->index + 1; |
| 392 | |
| 393 | for (i = 0; i < pagevec_count(&pvec); i++) { |
| 394 | struct page *page = pvec.pages[i], *dpage; |
| 395 | pgoff_t offset = page->index; |
| 396 | |
| 397 | lock_page(page); |
| 398 | dpage = find_lock_page(dmap, offset); |
| 399 | if (dpage) { |
| 400 | /* override existing page on the destination cache */ |
Ryusuke Konishi | 1f5abe7 | 2009-04-06 19:01:55 -0700 | [diff] [blame] | 401 | WARN_ON(PageDirty(dpage)); |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 402 | nilfs_copy_page(dpage, page, 0); |
| 403 | unlock_page(dpage); |
| 404 | page_cache_release(dpage); |
| 405 | } else { |
| 406 | struct page *page2; |
| 407 | |
| 408 | /* move the page to the destination cache */ |
| 409 | spin_lock_irq(&smap->tree_lock); |
| 410 | page2 = radix_tree_delete(&smap->page_tree, offset); |
Ryusuke Konishi | 1f5abe7 | 2009-04-06 19:01:55 -0700 | [diff] [blame] | 411 | WARN_ON(page2 != page); |
| 412 | |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 413 | smap->nrpages--; |
| 414 | spin_unlock_irq(&smap->tree_lock); |
| 415 | |
| 416 | spin_lock_irq(&dmap->tree_lock); |
| 417 | err = radix_tree_insert(&dmap->page_tree, offset, page); |
| 418 | if (unlikely(err < 0)) { |
Ryusuke Konishi | 1f5abe7 | 2009-04-06 19:01:55 -0700 | [diff] [blame] | 419 | WARN_ON(err == -EEXIST); |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 420 | page->mapping = NULL; |
| 421 | page_cache_release(page); /* for cache */ |
| 422 | } else { |
| 423 | page->mapping = dmap; |
| 424 | dmap->nrpages++; |
| 425 | if (PageDirty(page)) |
| 426 | radix_tree_tag_set(&dmap->page_tree, |
| 427 | offset, |
| 428 | PAGECACHE_TAG_DIRTY); |
| 429 | } |
| 430 | spin_unlock_irq(&dmap->tree_lock); |
| 431 | } |
| 432 | unlock_page(page); |
| 433 | } |
| 434 | pagevec_release(&pvec); |
| 435 | cond_resched(); |
| 436 | |
| 437 | goto repeat; |
| 438 | } |
| 439 | |
| 440 | void nilfs_clear_dirty_pages(struct address_space *mapping) |
| 441 | { |
| 442 | struct pagevec pvec; |
| 443 | unsigned int i; |
| 444 | pgoff_t index = 0; |
| 445 | |
| 446 | pagevec_init(&pvec, 0); |
| 447 | |
| 448 | while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY, |
| 449 | PAGEVEC_SIZE)) { |
| 450 | for (i = 0; i < pagevec_count(&pvec); i++) { |
| 451 | struct page *page = pvec.pages[i]; |
| 452 | struct buffer_head *bh, *head; |
| 453 | |
| 454 | lock_page(page); |
| 455 | ClearPageUptodate(page); |
| 456 | ClearPageMappedToDisk(page); |
| 457 | bh = head = page_buffers(page); |
| 458 | do { |
| 459 | lock_buffer(bh); |
| 460 | clear_buffer_dirty(bh); |
| 461 | clear_buffer_nilfs_volatile(bh); |
Ryusuke Konishi | 4e13e66 | 2010-07-18 10:42:25 +0900 | [diff] [blame] | 462 | clear_buffer_nilfs_checked(bh); |
Ryusuke Konishi | b1f6a4f | 2010-08-31 11:40:34 +0900 | [diff] [blame] | 463 | clear_buffer_nilfs_redirected(bh); |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 464 | clear_buffer_uptodate(bh); |
| 465 | clear_buffer_mapped(bh); |
| 466 | unlock_buffer(bh); |
| 467 | bh = bh->b_this_page; |
| 468 | } while (bh != head); |
| 469 | |
| 470 | __nilfs_clear_page_dirty(page); |
| 471 | unlock_page(page); |
| 472 | } |
| 473 | pagevec_release(&pvec); |
| 474 | cond_resched(); |
| 475 | } |
| 476 | } |
| 477 | |
| 478 | unsigned nilfs_page_count_clean_buffers(struct page *page, |
| 479 | unsigned from, unsigned to) |
| 480 | { |
| 481 | unsigned block_start, block_end; |
| 482 | struct buffer_head *bh, *head; |
| 483 | unsigned nc = 0; |
| 484 | |
| 485 | for (bh = head = page_buffers(page), block_start = 0; |
| 486 | bh != head || !block_start; |
| 487 | block_start = block_end, bh = bh->b_this_page) { |
| 488 | block_end = block_start + bh->b_size; |
| 489 | if (block_end > from && block_start < to && !buffer_dirty(bh)) |
| 490 | nc++; |
| 491 | } |
| 492 | return nc; |
| 493 | } |
Ryusuke Konishi | ae53a0a | 2010-12-26 23:30:02 +0900 | [diff] [blame] | 494 | |
Ryusuke Konishi | ebdfed4 | 2010-09-06 12:05:43 +0900 | [diff] [blame] | 495 | void nilfs_mapping_init(struct address_space *mapping, |
| 496 | struct backing_dev_info *bdi, |
| 497 | const struct address_space_operations *aops) |
| 498 | { |
| 499 | mapping->host = NULL; |
| 500 | mapping->flags = 0; |
| 501 | mapping_set_gfp_mask(mapping, GFP_NOFS); |
| 502 | mapping->assoc_mapping = NULL; |
| 503 | mapping->backing_dev_info = bdi; |
| 504 | mapping->a_ops = aops; |
| 505 | } |
Ryusuke Konishi | 0bd49f9 | 2009-04-06 19:01:27 -0700 | [diff] [blame] | 506 | |
| 507 | /* |
| 508 | * NILFS2 needs clear_page_dirty() in the following two cases: |
| 509 | * |
| 510 | * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears |
| 511 | * page dirty flags when it copies back pages from the shadow cache |
| 512 | * (gcdat->{i_mapping,i_btnode_cache}) to its original cache |
| 513 | * (dat->{i_mapping,i_btnode_cache}). |
| 514 | * |
| 515 | * 2) Some B-tree operations like insertion or deletion may dispose buffers |
| 516 | * in dirty state, and this needs to cancel the dirty state of their pages. |
| 517 | */ |
| 518 | int __nilfs_clear_page_dirty(struct page *page) |
| 519 | { |
| 520 | struct address_space *mapping = page->mapping; |
| 521 | |
| 522 | if (mapping) { |
| 523 | spin_lock_irq(&mapping->tree_lock); |
| 524 | if (test_bit(PG_dirty, &page->flags)) { |
| 525 | radix_tree_tag_clear(&mapping->page_tree, |
| 526 | page_index(page), |
| 527 | PAGECACHE_TAG_DIRTY); |
| 528 | spin_unlock_irq(&mapping->tree_lock); |
| 529 | return clear_page_dirty_for_io(page); |
| 530 | } |
| 531 | spin_unlock_irq(&mapping->tree_lock); |
| 532 | return 0; |
| 533 | } |
| 534 | return TestClearPageDirty(page); |
| 535 | } |
Ryusuke Konishi | 622daaff | 2010-12-26 16:38:43 +0900 | [diff] [blame] | 536 | |
| 537 | /** |
| 538 | * nilfs_find_uncommitted_extent - find extent of uncommitted data |
| 539 | * @inode: inode |
| 540 | * @start_blk: start block offset (in) |
| 541 | * @blkoff: start offset of the found extent (out) |
| 542 | * |
| 543 | * This function searches an extent of buffers marked "delayed" which |
| 544 | * starts from a block offset equal to or larger than @start_blk. If |
| 545 | * such an extent was found, this will store the start offset in |
| 546 | * @blkoff and return its length in blocks. Otherwise, zero is |
| 547 | * returned. |
| 548 | */ |
| 549 | unsigned long nilfs_find_uncommitted_extent(struct inode *inode, |
| 550 | sector_t start_blk, |
| 551 | sector_t *blkoff) |
| 552 | { |
| 553 | unsigned int i; |
| 554 | pgoff_t index; |
| 555 | unsigned int nblocks_in_page; |
| 556 | unsigned long length = 0; |
| 557 | sector_t b; |
| 558 | struct pagevec pvec; |
| 559 | struct page *page; |
| 560 | |
| 561 | if (inode->i_mapping->nrpages == 0) |
| 562 | return 0; |
| 563 | |
| 564 | index = start_blk >> (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 565 | nblocks_in_page = 1U << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 566 | |
| 567 | pagevec_init(&pvec, 0); |
| 568 | |
| 569 | repeat: |
| 570 | pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE, |
| 571 | pvec.pages); |
| 572 | if (pvec.nr == 0) |
| 573 | return length; |
| 574 | |
| 575 | if (length > 0 && pvec.pages[0]->index > index) |
| 576 | goto out; |
| 577 | |
| 578 | b = pvec.pages[0]->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 579 | i = 0; |
| 580 | do { |
| 581 | page = pvec.pages[i]; |
| 582 | |
| 583 | lock_page(page); |
| 584 | if (page_has_buffers(page)) { |
| 585 | struct buffer_head *bh, *head; |
| 586 | |
| 587 | bh = head = page_buffers(page); |
| 588 | do { |
| 589 | if (b < start_blk) |
| 590 | continue; |
| 591 | if (buffer_delay(bh)) { |
| 592 | if (length == 0) |
| 593 | *blkoff = b; |
| 594 | length++; |
| 595 | } else if (length > 0) { |
| 596 | goto out_locked; |
| 597 | } |
| 598 | } while (++b, bh = bh->b_this_page, bh != head); |
| 599 | } else { |
| 600 | if (length > 0) |
| 601 | goto out_locked; |
| 602 | |
| 603 | b += nblocks_in_page; |
| 604 | } |
| 605 | unlock_page(page); |
| 606 | |
| 607 | } while (++i < pagevec_count(&pvec)); |
| 608 | |
| 609 | index = page->index + 1; |
| 610 | pagevec_release(&pvec); |
| 611 | cond_resched(); |
| 612 | goto repeat; |
| 613 | |
| 614 | out_locked: |
| 615 | unlock_page(page); |
| 616 | out: |
| 617 | pagevec_release(&pvec); |
| 618 | return length; |
| 619 | } |