Blame view
fs/buffer.c
85.1 KB
1da177e4c
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 |
/* * linux/fs/buffer.c * * Copyright (C) 1991, 1992, 2002 Linus Torvalds */ /* * Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95 * * Removed a lot of unnecessary code and simplified things now that * the buffer cache isn't our primary cache - Andrew Tridgell 12/96 * * Speed up hash, lru, and free list operations. Use gfp() for allocating * hash table, use SLAB cache for buffer heads. SMP threading. -DaveM * * Added 32k buffer block sizes - these are required older ARM systems. - RMK * * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de> */ |
1da177e4c
|
20 21 22 23 24 25 |
#include <linux/kernel.h> #include <linux/syscalls.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/percpu.h> #include <linux/slab.h> |
16f7e0fe2
|
26 |
#include <linux/capability.h> |
1da177e4c
|
27 28 29 30 |
#include <linux/blkdev.h> #include <linux/file.h> #include <linux/quotaops.h> #include <linux/highmem.h> |
630d9c472
|
31 |
#include <linux/export.h> |
1da177e4c
|
32 33 34 35 |
#include <linux/writeback.h> #include <linux/hash.h> #include <linux/suspend.h> #include <linux/buffer_head.h> |
55e829af0
|
36 |
#include <linux/task_io_accounting_ops.h> |
1da177e4c
|
37 38 39 40 41 |
#include <linux/bio.h> #include <linux/notifier.h> #include <linux/cpu.h> #include <linux/bitops.h> #include <linux/mpage.h> |
fb1c8f93d
|
42 |
#include <linux/bit_spinlock.h> |
1da177e4c
|
43 44 |
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); |
1da177e4c
|
45 46 47 48 49 50 51 52 53 |
#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers) inline void init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) { bh->b_end_io = handler; bh->b_private = private; } |
1fe72eaa0
|
54 |
EXPORT_SYMBOL(init_buffer); |
1da177e4c
|
55 |
|
7eaceacca
|
56 |
static int sleep_on_buffer(void *word) |
1da177e4c
|
57 |
{ |
1da177e4c
|
58 59 60 |
io_schedule(); return 0; } |
fc9b52cd8
|
61 |
void __lock_buffer(struct buffer_head *bh) |
1da177e4c
|
62 |
{ |
7eaceacca
|
63 |
wait_on_bit_lock(&bh->b_state, BH_Lock, sleep_on_buffer, |
1da177e4c
|
64 65 66 |
TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(__lock_buffer); |
fc9b52cd8
|
67 |
void unlock_buffer(struct buffer_head *bh) |
1da177e4c
|
68 |
{ |
51b07fc3c
|
69 |
clear_bit_unlock(BH_Lock, &bh->b_state); |
1da177e4c
|
70 71 72 |
smp_mb__after_clear_bit(); wake_up_bit(&bh->b_state, BH_Lock); } |
1fe72eaa0
|
73 |
EXPORT_SYMBOL(unlock_buffer); |
1da177e4c
|
74 75 76 77 78 79 80 81 |
/* * Block until a buffer comes unlocked. This doesn't stop it * from becoming locked again - you have to lock it yourself * if you want to preserve its state. */ void __wait_on_buffer(struct buffer_head * bh) { |
7eaceacca
|
82 |
wait_on_bit(&bh->b_state, BH_Lock, sleep_on_buffer, TASK_UNINTERRUPTIBLE); |
1da177e4c
|
83 |
} |
1fe72eaa0
|
84 |
EXPORT_SYMBOL(__wait_on_buffer); |
1da177e4c
|
85 86 87 88 89 |
static void __clear_page_buffers(struct page *page) { ClearPagePrivate(page); |
4c21e2f24
|
90 |
set_page_private(page, 0); |
1da177e4c
|
91 92 |
page_cache_release(page); } |
08bafc034
|
93 94 95 96 97 98 99 |
static int quiet_error(struct buffer_head *bh) { if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit()) return 0; return 1; } |
1da177e4c
|
100 101 102 |
static void buffer_io_error(struct buffer_head *bh) { char b[BDEVNAME_SIZE]; |
1da177e4c
|
103 104 105 106 107 108 109 |
printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu ", bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr); } /* |
68671f35f
|
110 111 112 113 114 115 |
* End-of-IO handler helper function which does not touch the bh after * unlocking it. * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but * a race there is benign: unlock_buffer() only use the bh's address for * hashing after unlocking the buffer, so it doesn't actually touch the bh * itself. |
1da177e4c
|
116 |
*/ |
68671f35f
|
117 |
static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate) |
1da177e4c
|
118 119 120 121 122 123 124 125 |
{ if (uptodate) { set_buffer_uptodate(bh); } else { /* This happens, due to failed READA attempts. */ clear_buffer_uptodate(bh); } unlock_buffer(bh); |
68671f35f
|
126 127 128 129 130 131 132 133 134 |
} /* * Default synchronous end-of-IO handler.. Just mark it up-to-date and * unlock the buffer. This is what ll_rw_block uses too. */ void end_buffer_read_sync(struct buffer_head *bh, int uptodate) { __end_buffer_read_notouch(bh, uptodate); |
1da177e4c
|
135 136 |
put_bh(bh); } |
1fe72eaa0
|
137 |
EXPORT_SYMBOL(end_buffer_read_sync); |
1da177e4c
|
138 139 140 141 142 143 144 145 |
void end_buffer_write_sync(struct buffer_head *bh, int uptodate) { char b[BDEVNAME_SIZE]; if (uptodate) { set_buffer_uptodate(bh); } else { |
0edd55fae
|
146 |
if (!quiet_error(bh)) { |
1da177e4c
|
147 148 149 150 151 152 153 154 155 156 157 158 |
buffer_io_error(bh); printk(KERN_WARNING "lost page write due to " "I/O error on %s ", bdevname(bh->b_bdev, b)); } set_buffer_write_io_error(bh); clear_buffer_uptodate(bh); } unlock_buffer(bh); put_bh(bh); } |
1fe72eaa0
|
159 |
EXPORT_SYMBOL(end_buffer_write_sync); |
1da177e4c
|
160 161 |
/* |
1da177e4c
|
162 163 164 165 166 167 168 169 170 171 172 |
* Various filesystems appear to want __find_get_block to be non-blocking. * But it's the page lock which protects the buffers. To get around this, * we get exclusion from try_to_free_buffers with the blockdev mapping's * private_lock. * * Hack idea: for the blockdev mapping, i_bufferlist_lock contention * may be quite high. This code could TryLock the page, and if that * succeeds, there is no need to take private_lock. (But if * private_lock is contended then so is mapping->tree_lock). */ static struct buffer_head * |
385fd4c59
|
173 |
__find_get_block_slow(struct block_device *bdev, sector_t block) |
1da177e4c
|
174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 |
{ struct inode *bd_inode = bdev->bd_inode; struct address_space *bd_mapping = bd_inode->i_mapping; struct buffer_head *ret = NULL; pgoff_t index; struct buffer_head *bh; struct buffer_head *head; struct page *page; int all_mapped = 1; index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits); page = find_get_page(bd_mapping, index); if (!page) goto out; spin_lock(&bd_mapping->private_lock); if (!page_has_buffers(page)) goto out_unlock; head = page_buffers(page); bh = head; do { |
97f76d3d1
|
195 196 197 |
if (!buffer_mapped(bh)) all_mapped = 0; else if (bh->b_blocknr == block) { |
1da177e4c
|
198 199 200 201 |
ret = bh; get_bh(bh); goto out_unlock; } |
1da177e4c
|
202 203 204 205 206 207 208 209 210 |
bh = bh->b_this_page; } while (bh != head); /* we might be here because some of the buffers on this page are * not mapped. This is due to various races between * file io on the block device and getblk. It gets dealt with * elsewhere, don't buffer_error if we had some unmapped buffers */ if (all_mapped) { |
72a2ebd8b
|
211 |
char b[BDEVNAME_SIZE]; |
1da177e4c
|
212 213 214 |
printk("__find_get_block_slow() failed. " "block=%llu, b_blocknr=%llu ", |
205f87f6b
|
215 216 217 218 219 |
(unsigned long long)block, (unsigned long long)bh->b_blocknr); printk("b_state=0x%08lx, b_size=%zu ", bh->b_state, bh->b_size); |
72a2ebd8b
|
220 221 222 |
printk("device %s blocksize: %d ", bdevname(bdev, b), 1 << bd_inode->i_blkbits); |
1da177e4c
|
223 224 225 226 227 228 229 |
} out_unlock: spin_unlock(&bd_mapping->private_lock); page_cache_release(page); out: return ret; } |
1da177e4c
|
230 |
/* |
5b0830cb9
|
231 |
* Kick the writeback threads then try to free up some ZONE_NORMAL memory. |
1da177e4c
|
232 233 234 |
*/ static void free_more_memory(void) { |
19770b326
|
235 |
struct zone *zone; |
0e88460da
|
236 |
int nid; |
1da177e4c
|
237 |
|
0e175a183
|
238 |
wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM); |
1da177e4c
|
239 |
yield(); |
0e88460da
|
240 |
for_each_online_node(nid) { |
19770b326
|
241 242 243 244 |
(void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS), gfp_zone(GFP_NOFS), NULL, &zone); if (zone) |
54a6eb5c4
|
245 |
try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0, |
327c0e968
|
246 |
GFP_NOFS, NULL); |
1da177e4c
|
247 248 249 250 251 252 253 254 255 |
} } /* * I/O completion handler for block_read_full_page() - pages * which come unlocked at the end of I/O. */ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) { |
1da177e4c
|
256 |
unsigned long flags; |
a39722034
|
257 |
struct buffer_head *first; |
1da177e4c
|
258 259 260 261 262 263 264 265 266 267 268 |
struct buffer_head *tmp; struct page *page; int page_uptodate = 1; BUG_ON(!buffer_async_read(bh)); page = bh->b_page; if (uptodate) { set_buffer_uptodate(bh); } else { clear_buffer_uptodate(bh); |
08bafc034
|
269 |
if (!quiet_error(bh)) |
1da177e4c
|
270 271 272 273 274 275 276 277 278 |
buffer_io_error(bh); SetPageError(page); } /* * Be _very_ careful from here on. Bad things can happen if * two buffer heads end IO at almost the same time and both * decide that the page is now completely done. */ |
a39722034
|
279 280 281 |
first = page_buffers(page); local_irq_save(flags); bit_spin_lock(BH_Uptodate_Lock, &first->b_state); |
1da177e4c
|
282 283 284 285 286 287 288 289 290 291 292 293 |
clear_buffer_async_read(bh); unlock_buffer(bh); tmp = bh; do { if (!buffer_uptodate(tmp)) page_uptodate = 0; if (buffer_async_read(tmp)) { BUG_ON(!buffer_locked(tmp)); goto still_busy; } tmp = tmp->b_this_page; } while (tmp != bh); |
a39722034
|
294 295 |
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); local_irq_restore(flags); |
1da177e4c
|
296 297 298 299 300 301 302 303 304 305 306 |
/* * If none of the buffers had errors and they are all * uptodate then we can set the page uptodate. */ if (page_uptodate && !PageError(page)) SetPageUptodate(page); unlock_page(page); return; still_busy: |
a39722034
|
307 308 |
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); local_irq_restore(flags); |
1da177e4c
|
309 310 311 312 313 314 315 |
return; } /* * Completion handler for block_write_full_page() - pages which are unlocked * during I/O, and which have PageWriteback cleared upon I/O completion. */ |
35c80d5f4
|
316 |
void end_buffer_async_write(struct buffer_head *bh, int uptodate) |
1da177e4c
|
317 318 |
{ char b[BDEVNAME_SIZE]; |
1da177e4c
|
319 |
unsigned long flags; |
a39722034
|
320 |
struct buffer_head *first; |
1da177e4c
|
321 322 323 324 325 326 327 328 329 |
struct buffer_head *tmp; struct page *page; BUG_ON(!buffer_async_write(bh)); page = bh->b_page; if (uptodate) { set_buffer_uptodate(bh); } else { |
08bafc034
|
330 |
if (!quiet_error(bh)) { |
1da177e4c
|
331 332 333 334 335 336 337 |
buffer_io_error(bh); printk(KERN_WARNING "lost page write due to " "I/O error on %s ", bdevname(bh->b_bdev, b)); } set_bit(AS_EIO, &page->mapping->flags); |
58ff407be
|
338 |
set_buffer_write_io_error(bh); |
1da177e4c
|
339 340 341 |
clear_buffer_uptodate(bh); SetPageError(page); } |
a39722034
|
342 343 344 |
first = page_buffers(page); local_irq_save(flags); bit_spin_lock(BH_Uptodate_Lock, &first->b_state); |
1da177e4c
|
345 346 347 348 349 350 351 352 353 354 |
clear_buffer_async_write(bh); unlock_buffer(bh); tmp = bh->b_this_page; while (tmp != bh) { if (buffer_async_write(tmp)) { BUG_ON(!buffer_locked(tmp)); goto still_busy; } tmp = tmp->b_this_page; } |
a39722034
|
355 356 |
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); local_irq_restore(flags); |
1da177e4c
|
357 358 359 360 |
end_page_writeback(page); return; still_busy: |
a39722034
|
361 362 |
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); local_irq_restore(flags); |
1da177e4c
|
363 364 |
return; } |
1fe72eaa0
|
365 |
EXPORT_SYMBOL(end_buffer_async_write); |
1da177e4c
|
366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 |
/* * If a page's buffers are under async readin (end_buffer_async_read * completion) then there is a possibility that another thread of * control could lock one of the buffers after it has completed * but while some of the other buffers have not completed. This * locked buffer would confuse end_buffer_async_read() into not unlocking * the page. So the absence of BH_Async_Read tells end_buffer_async_read() * that this buffer is not under async I/O. * * The page comes unlocked when it has no locked buffer_async buffers * left. * * PageLocked prevents anyone starting new async I/O reads any of * the buffers. * * PageWriteback is used to prevent simultaneous writeout of the same * page. * * PageLocked prevents anyone from starting writeback of a page which is * under read I/O (PageWriteback is only ever set against a locked page). */ static void mark_buffer_async_read(struct buffer_head *bh) { bh->b_end_io = end_buffer_async_read; set_buffer_async_read(bh); } |
1fe72eaa0
|
393 394 |
static void mark_buffer_async_write_endio(struct buffer_head *bh, bh_end_io_t *handler) |
1da177e4c
|
395 |
{ |
35c80d5f4
|
396 |
bh->b_end_io = handler; |
1da177e4c
|
397 398 |
set_buffer_async_write(bh); } |
35c80d5f4
|
399 400 401 402 403 |
void mark_buffer_async_write(struct buffer_head *bh) { mark_buffer_async_write_endio(bh, end_buffer_async_write); } |
1da177e4c
|
404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 |
EXPORT_SYMBOL(mark_buffer_async_write); /* * fs/buffer.c contains helper functions for buffer-backed address space's * fsync functions. A common requirement for buffer-based filesystems is * that certain data from the backing blockdev needs to be written out for * a successful fsync(). For example, ext2 indirect blocks need to be * written back and waited upon before fsync() returns. * * The functions mark_buffer_inode_dirty(), fsync_inode_buffers(), * inode_has_buffers() and invalidate_inode_buffers() are provided for the * management of a list of dependent buffers at ->i_mapping->private_list. * * Locking is a little subtle: try_to_free_buffers() will remove buffers * from their controlling inode's queue when they are being freed. But * try_to_free_buffers() will be operating against the *blockdev* mapping * at the time, not against the S_ISREG file which depends on those buffers. * So the locking for private_list is via the private_lock in the address_space * which backs the buffers. Which is different from the address_space * against which the buffers are listed. So for a particular address_space, * mapping->private_lock does *not* protect mapping->private_list! In fact, * mapping->private_list will always be protected by the backing blockdev's * ->private_lock. * * Which introduces a requirement: all buffers on an address_space's * ->private_list must be from the same address_space: the blockdev's. * * address_spaces which do not place buffers at ->private_list via these * utility functions are free to use private_lock and private_list for * whatever they want. The only requirement is that list_empty(private_list) * be true at clear_inode() time. * * FIXME: clear_inode should not call invalidate_inode_buffers(). The * filesystems should do that. invalidate_inode_buffers() should just go * BUG_ON(!list_empty). * * FIXME: mark_buffer_dirty_inode() is a data-plane operation. It should * take an address_space, not an inode. And it should be called * mark_buffer_dirty_fsync() to clearly define why those buffers are being * queued up. * * FIXME: mark_buffer_dirty_inode() doesn't need to add the buffer to the * list if it is already on a list. Because if the buffer is on a list, * it *must* already be on the right one. If not, the filesystem is being * silly. This will save a ton of locking. But first we have to ensure * that buffers are taken *off* the old inode's list when they are freed * (presumably in truncate). That requires careful auditing of all * filesystems (do it inside bforget()). It could also be done by bringing * b_inode back. */ /* * The buffer's backing address_space's private_lock must be held */ |
dbacefc9c
|
459 |
static void __remove_assoc_queue(struct buffer_head *bh) |
1da177e4c
|
460 461 |
{ list_del_init(&bh->b_assoc_buffers); |
58ff407be
|
462 463 464 465 |
WARN_ON(!bh->b_assoc_map); if (buffer_write_io_error(bh)) set_bit(AS_EIO, &bh->b_assoc_map->flags); bh->b_assoc_map = NULL; |
1da177e4c
|
466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 |
} int inode_has_buffers(struct inode *inode) { return !list_empty(&inode->i_data.private_list); } /* * osync is designed to support O_SYNC io. It waits synchronously for * all already-submitted IO to complete, but does not queue any new * writes to the disk. * * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as * you dirty the buffers, and then use osync_inode_buffers to wait for * completion. Any other dirty buffers which are not yet queued for * write will not be flushed to disk by the osync. */ static int osync_buffers_list(spinlock_t *lock, struct list_head *list) { struct buffer_head *bh; struct list_head *p; int err = 0; spin_lock(lock); repeat: list_for_each_prev(p, list) { bh = BH_ENTRY(p); if (buffer_locked(bh)) { get_bh(bh); spin_unlock(lock); wait_on_buffer(bh); if (!buffer_uptodate(bh)) err = -EIO; brelse(bh); spin_lock(lock); goto repeat; } } spin_unlock(lock); return err; } |
01a05b337
|
507 |
static void do_thaw_one(struct super_block *sb, void *unused) |
c2d754385
|
508 |
{ |
c2d754385
|
509 |
char b[BDEVNAME_SIZE]; |
01a05b337
|
510 511 512 513 514 |
while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb)) printk(KERN_WARNING "Emergency Thaw on %s ", bdevname(sb->s_bdev, b)); } |
c2d754385
|
515 |
|
01a05b337
|
516 517 518 |
static void do_thaw_all(struct work_struct *work) { iterate_supers(do_thaw_one, NULL); |
053c525fc
|
519 |
kfree(work); |
c2d754385
|
520 521 522 523 524 525 526 527 528 529 530 |
printk(KERN_WARNING "Emergency Thaw complete "); } /** * emergency_thaw_all -- forcibly thaw every frozen filesystem * * Used for emergency unfreeze of all filesystems via SysRq */ void emergency_thaw_all(void) { |
053c525fc
|
531 532 533 534 535 536 537 |
struct work_struct *work; work = kmalloc(sizeof(*work), GFP_ATOMIC); if (work) { INIT_WORK(work, do_thaw_all); schedule_work(work); } |
c2d754385
|
538 |
} |
1da177e4c
|
539 |
/** |
78a4a50a8
|
540 |
* sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers |
67be2dd1b
|
541 |
* @mapping: the mapping which wants those buffers written |
1da177e4c
|
542 543 544 545 |
* * Starts I/O against the buffers at mapping->private_list, and waits upon * that I/O. * |
67be2dd1b
|
546 547 548 |
* Basically, this is a convenience function for fsync(). * @mapping is a file or directory which needs those buffers to be written for * a successful fsync(). |
1da177e4c
|
549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 |
*/ int sync_mapping_buffers(struct address_space *mapping) { struct address_space *buffer_mapping = mapping->assoc_mapping; if (buffer_mapping == NULL || list_empty(&mapping->private_list)) return 0; return fsync_buffers_list(&buffer_mapping->private_lock, &mapping->private_list); } EXPORT_SYMBOL(sync_mapping_buffers); /* * Called when we've recently written block `bblock', and it is known that * `bblock' was for a buffer_boundary() buffer. This means that the block at * `bblock + 1' is probably a dirty indirect block. Hunt it down and, if it's * dirty, schedule it for IO. So that indirects merge nicely with their data. */ void write_boundary_block(struct block_device *bdev, sector_t bblock, unsigned blocksize) { struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize); if (bh) { if (buffer_dirty(bh)) ll_rw_block(WRITE, 1, &bh); put_bh(bh); } } void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode) { struct address_space *mapping = inode->i_mapping; struct address_space *buffer_mapping = bh->b_page->mapping; mark_buffer_dirty(bh); if (!mapping->assoc_mapping) { mapping->assoc_mapping = buffer_mapping; } else { |
e827f9235
|
588 |
BUG_ON(mapping->assoc_mapping != buffer_mapping); |
1da177e4c
|
589 |
} |
535ee2fbf
|
590 |
if (!bh->b_assoc_map) { |
1da177e4c
|
591 592 593 |
spin_lock(&buffer_mapping->private_lock); list_move_tail(&bh->b_assoc_buffers, &mapping->private_list); |
58ff407be
|
594 |
bh->b_assoc_map = mapping; |
1da177e4c
|
595 596 597 598 599 600 |
spin_unlock(&buffer_mapping->private_lock); } } EXPORT_SYMBOL(mark_buffer_dirty_inode); /* |
787d2214c
|
601 602 603 604 605 606 |
* Mark the page dirty, and set it dirty in the radix tree, and mark the inode * dirty. * * If warn is true, then emit a warning if the page is not uptodate and has * not been truncated. */ |
a8e7d49aa
|
607 |
static void __set_page_dirty(struct page *page, |
787d2214c
|
608 609 |
struct address_space *mapping, int warn) { |
19fd62312
|
610 |
spin_lock_irq(&mapping->tree_lock); |
787d2214c
|
611 612 |
if (page->mapping) { /* Race with truncate? */ WARN_ON_ONCE(warn && !PageUptodate(page)); |
e3a7cca1e
|
613 |
account_page_dirtied(page, mapping); |
787d2214c
|
614 615 616 |
radix_tree_tag_set(&mapping->page_tree, page_index(page), PAGECACHE_TAG_DIRTY); } |
19fd62312
|
617 |
spin_unlock_irq(&mapping->tree_lock); |
787d2214c
|
618 |
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
787d2214c
|
619 620 621 |
} /* |
1da177e4c
|
622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 |
* Add a page to the dirty page list. * * It is a sad fact of life that this function is called from several places * deeply under spinlocking. It may not sleep. * * If the page has buffers, the uptodate buffers are set dirty, to preserve * dirty-state coherency between the page and the buffers. It the page does * not have buffers then when they are later attached they will all be set * dirty. * * The buffers are dirtied before the page is dirtied. There's a small race * window in which a writepage caller may see the page cleanness but not the * buffer dirtiness. That's fine. If this code were to set the page dirty * before the buffers, a concurrent writepage caller could clear the page dirty * bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean * page on the dirty page list. * * We use private_lock to lock against try_to_free_buffers while using the * page's buffer list. Also use this to protect against clean buffers being * added to the page after it was set dirty. * * FIXME: may need to call ->reservepage here as well. That's rather up to the * address_space though. */ int __set_page_dirty_buffers(struct page *page) { |
a8e7d49aa
|
648 |
int newly_dirty; |
787d2214c
|
649 |
struct address_space *mapping = page_mapping(page); |
ebf7a227d
|
650 651 652 |
if (unlikely(!mapping)) return !TestSetPageDirty(page); |
1da177e4c
|
653 654 655 656 657 658 659 660 661 662 663 |
spin_lock(&mapping->private_lock); if (page_has_buffers(page)) { struct buffer_head *head = page_buffers(page); struct buffer_head *bh = head; do { set_buffer_dirty(bh); bh = bh->b_this_page; } while (bh != head); } |
a8e7d49aa
|
664 |
newly_dirty = !TestSetPageDirty(page); |
1da177e4c
|
665 |
spin_unlock(&mapping->private_lock); |
a8e7d49aa
|
666 667 668 |
if (newly_dirty) __set_page_dirty(page, mapping, 1); return newly_dirty; |
1da177e4c
|
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 |
} EXPORT_SYMBOL(__set_page_dirty_buffers); /* * Write out and wait upon a list of buffers. * * We have conflicting pressures: we want to make sure that all * initially dirty buffers get waited on, but that any subsequently * dirtied buffers don't. After all, we don't want fsync to last * forever if somebody is actively writing to the file. * * Do this in two main stages: first we copy dirty buffers to a * temporary inode list, queueing the writes as we go. Then we clean * up, waiting for those writes to complete. * * During this second stage, any subsequent updates to the file may end * up refiling the buffer on the original inode's dirty list again, so * there is a chance we will end up with a buffer queued for write but * not yet completed on that list. So, as a final cleanup we go through * the osync code to catch these locked, dirty buffers without requeuing * any newly dirty buffers for write. */ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) { struct buffer_head *bh; struct list_head tmp; |
7eaceacca
|
695 |
struct address_space *mapping; |
1da177e4c
|
696 |
int err = 0, err2; |
4ee2491ed
|
697 |
struct blk_plug plug; |
1da177e4c
|
698 699 |
INIT_LIST_HEAD(&tmp); |
4ee2491ed
|
700 |
blk_start_plug(&plug); |
1da177e4c
|
701 702 703 704 |
spin_lock(lock); while (!list_empty(list)) { bh = BH_ENTRY(list->next); |
535ee2fbf
|
705 |
mapping = bh->b_assoc_map; |
58ff407be
|
706 |
__remove_assoc_queue(bh); |
535ee2fbf
|
707 708 709 |
/* Avoid race with mark_buffer_dirty_inode() which does * a lockless check and we rely on seeing the dirty bit */ smp_mb(); |
1da177e4c
|
710 711 |
if (buffer_dirty(bh) || buffer_locked(bh)) { list_add(&bh->b_assoc_buffers, &tmp); |
535ee2fbf
|
712 |
bh->b_assoc_map = mapping; |
1da177e4c
|
713 714 715 716 717 |
if (buffer_dirty(bh)) { get_bh(bh); spin_unlock(lock); /* * Ensure any pending I/O completes so that |
9cb569d60
|
718 719 720 721 |
* write_dirty_buffer() actually writes the * current contents - it is a noop if I/O is * still in flight on potentially older * contents. |
1da177e4c
|
722 |
*/ |
721a9602e
|
723 |
write_dirty_buffer(bh, WRITE_SYNC); |
9cf6b720f
|
724 725 726 727 728 729 730 |
/* * Kick off IO for the previous mapping. Note * that we will not run the very last mapping, * wait_on_buffer() will do that for us * through sync_buffer(). */ |
1da177e4c
|
731 732 733 734 735 |
brelse(bh); spin_lock(lock); } } } |
4ee2491ed
|
736 737 738 |
spin_unlock(lock); blk_finish_plug(&plug); spin_lock(lock); |
1da177e4c
|
739 740 |
while (!list_empty(&tmp)) { bh = BH_ENTRY(tmp.prev); |
1da177e4c
|
741 |
get_bh(bh); |
535ee2fbf
|
742 743 744 745 746 747 748 |
mapping = bh->b_assoc_map; __remove_assoc_queue(bh); /* Avoid race with mark_buffer_dirty_inode() which does * a lockless check and we rely on seeing the dirty bit */ smp_mb(); if (buffer_dirty(bh)) { list_add(&bh->b_assoc_buffers, |
e3892296d
|
749 |
&mapping->private_list); |
535ee2fbf
|
750 751 |
bh->b_assoc_map = mapping; } |
1da177e4c
|
752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 |
spin_unlock(lock); wait_on_buffer(bh); if (!buffer_uptodate(bh)) err = -EIO; brelse(bh); spin_lock(lock); } spin_unlock(lock); err2 = osync_buffers_list(lock, list); if (err) return err; else return err2; } /* * Invalidate any and all dirty buffers on a given inode. We are * probably unmounting the fs, but that doesn't mean we have already * done a sync(). Just drop the buffers from the inode list. * * NOTE: we take the inode's blockdev's mapping's private_lock. Which * assumes that all the buffers are against the blockdev. Not true * for reiserfs. */ void invalidate_inode_buffers(struct inode *inode) { if (inode_has_buffers(inode)) { struct address_space *mapping = &inode->i_data; struct list_head *list = &mapping->private_list; struct address_space *buffer_mapping = mapping->assoc_mapping; spin_lock(&buffer_mapping->private_lock); while (!list_empty(list)) __remove_assoc_queue(BH_ENTRY(list->next)); spin_unlock(&buffer_mapping->private_lock); } } |
52b19ac99
|
790 |
EXPORT_SYMBOL(invalidate_inode_buffers); |
1da177e4c
|
791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 |
/* * Remove any clean buffers from the inode's buffer list. This is called * when we're trying to free the inode itself. Those buffers can pin it. * * Returns true if all buffers were removed. */ int remove_inode_buffers(struct inode *inode) { int ret = 1; if (inode_has_buffers(inode)) { struct address_space *mapping = &inode->i_data; struct list_head *list = &mapping->private_list; struct address_space *buffer_mapping = mapping->assoc_mapping; spin_lock(&buffer_mapping->private_lock); while (!list_empty(list)) { struct buffer_head *bh = BH_ENTRY(list->next); if (buffer_dirty(bh)) { ret = 0; break; } __remove_assoc_queue(bh); } spin_unlock(&buffer_mapping->private_lock); } return ret; } /* * Create the appropriate buffers when given a page for data area and * the size of each buffer.. Use the bh->b_this_page linked list to * follow the buffers created. Return NULL if unable to create more * buffers. * * The retry flag is used to differentiate async IO (paging, swapping) * which may not fail from ordinary buffer allocations. */ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, int retry) { struct buffer_head *bh, *head; long offset; try_again: head = NULL; offset = PAGE_SIZE; while ((offset -= size) >= 0) { bh = alloc_buffer_head(GFP_NOFS); if (!bh) goto no_grow; bh->b_bdev = NULL; bh->b_this_page = head; bh->b_blocknr = -1; head = bh; bh->b_state = 0; atomic_set(&bh->b_count, 0); bh->b_size = size; /* Link the buffer to its page */ set_bh_page(bh, page, offset); |
01ffe339e
|
855 |
init_buffer(bh, NULL, NULL); |
1da177e4c
|
856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 |
} return head; /* * In case anything failed, we just free everything we got. */ no_grow: if (head) { do { bh = head; head = head->b_this_page; free_buffer_head(bh); } while (head); } /* * Return failure for non-async IO requests. Async IO requests * are not allowed to fail, so we have to wait until buffer heads * become available. But we don't want tasks sleeping with * partially complete buffers, so all were released above. */ if (!retry) return NULL; /* We're _really_ low on memory. Now we just * wait for old buffer heads to become free due to * finishing IO. Since this is an async request and * the reserve list is empty, we're sure there are * async buffer heads in use. */ free_more_memory(); goto try_again; } EXPORT_SYMBOL_GPL(alloc_page_buffers); static inline void link_dev_buffers(struct page *page, struct buffer_head *head) { struct buffer_head *bh, *tail; bh = head; do { tail = bh; bh = bh->b_this_page; } while (bh); tail->b_this_page = head; attach_page_buffers(page, head); } /* * Initialise the state of a blockdev page's buffers. */ |
676ce6d5c
|
907 |
static sector_t |
1da177e4c
|
908 909 910 911 912 913 |
init_page_buffers(struct page *page, struct block_device *bdev, sector_t block, int size) { struct buffer_head *head = page_buffers(page); struct buffer_head *bh = head; int uptodate = PageUptodate(page); |
080399aaa
|
914 |
sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode)); |
1da177e4c
|
915 916 917 918 919 920 921 922 |
do { if (!buffer_mapped(bh)) { init_buffer(bh, NULL, NULL); bh->b_bdev = bdev; bh->b_blocknr = block; if (uptodate) set_buffer_uptodate(bh); |
080399aaa
|
923 924 |
if (block < end_block) set_buffer_mapped(bh); |
1da177e4c
|
925 926 927 928 |
} block++; bh = bh->b_this_page; } while (bh != head); |
676ce6d5c
|
929 930 931 932 933 |
/* * Caller needs to validate requested block against end of device. */ return end_block; |
1da177e4c
|
934 935 936 937 938 |
} /* * Create the page-cache page that contains the requested block. * |
676ce6d5c
|
939 |
* This is used purely for blockdev mappings. |
1da177e4c
|
940 |
*/ |
676ce6d5c
|
941 |
static int |
1da177e4c
|
942 |
grow_dev_page(struct block_device *bdev, sector_t block, |
676ce6d5c
|
943 |
pgoff_t index, int size, int sizebits) |
1da177e4c
|
944 945 946 947 |
{ struct inode *inode = bdev->bd_inode; struct page *page; struct buffer_head *bh; |
676ce6d5c
|
948 949 |
sector_t end_block; int ret = 0; /* Will call free_more_memory() */ |
1da177e4c
|
950 |
|
ea125892a
|
951 |
page = find_or_create_page(inode->i_mapping, index, |
769848c03
|
952 |
(mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); |
1da177e4c
|
953 |
if (!page) |
676ce6d5c
|
954 |
return ret; |
1da177e4c
|
955 |
|
e827f9235
|
956 |
BUG_ON(!PageLocked(page)); |
1da177e4c
|
957 958 959 960 |
if (page_has_buffers(page)) { bh = page_buffers(page); if (bh->b_size == size) { |
676ce6d5c
|
961 962 963 |
end_block = init_page_buffers(page, bdev, index << sizebits, size); goto done; |
1da177e4c
|
964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 |
} if (!try_to_free_buffers(page)) goto failed; } /* * Allocate some buffers for this page */ bh = alloc_page_buffers(page, size, 0); if (!bh) goto failed; /* * Link the page to the buffers and initialise them. Take the * lock to be atomic wrt __find_get_block(), which does not * run under the page lock. */ spin_lock(&inode->i_mapping->private_lock); link_dev_buffers(page, bh); |
676ce6d5c
|
983 |
end_block = init_page_buffers(page, bdev, index << sizebits, size); |
1da177e4c
|
984 |
spin_unlock(&inode->i_mapping->private_lock); |
676ce6d5c
|
985 986 |
done: ret = (block < end_block) ? 1 : -ENXIO; |
1da177e4c
|
987 |
failed: |
1da177e4c
|
988 989 |
unlock_page(page); page_cache_release(page); |
676ce6d5c
|
990 |
return ret; |
1da177e4c
|
991 992 993 994 995 |
} /* * Create buffers for the specified block device block's page. If * that page was dirty, the buffers are set dirty also. |
1da177e4c
|
996 |
*/ |
858119e15
|
997 |
static int |
1da177e4c
|
998 999 |
grow_buffers(struct block_device *bdev, sector_t block, int size) { |
1da177e4c
|
1000 1001 1002 1003 1004 1005 1006 1007 1008 |
pgoff_t index; int sizebits; sizebits = -1; do { sizebits++; } while ((size << sizebits) < PAGE_SIZE); index = block >> sizebits; |
1da177e4c
|
1009 |
|
e56579338
|
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 |
/* * Check for a block which wants to lie outside our maximum possible * pagecache index. (this comparison is done using sector_t types). */ if (unlikely(index != block >> sizebits)) { char b[BDEVNAME_SIZE]; printk(KERN_ERR "%s: requested out-of-range block %llu for " "device %s ", |
8e24eea72
|
1020 |
__func__, (unsigned long long)block, |
e56579338
|
1021 1022 1023 |
bdevname(bdev, b)); return -EIO; } |
676ce6d5c
|
1024 |
|
1da177e4c
|
1025 |
/* Create a page with the proper size buffers.. */ |
676ce6d5c
|
1026 |
return grow_dev_page(bdev, block, index, size, sizebits); |
1da177e4c
|
1027 |
} |
75c96f858
|
1028 |
static struct buffer_head * |
1da177e4c
|
1029 1030 1031 |
__getblk_slow(struct block_device *bdev, sector_t block, int size) { /* Size must be multiple of hard sectorsize */ |
e1defc4ff
|
1032 |
if (unlikely(size & (bdev_logical_block_size(bdev)-1) || |
1da177e4c
|
1033 1034 1035 1036 |
(size < 512 || size > PAGE_SIZE))) { printk(KERN_ERR "getblk(): invalid block size %d requested ", size); |
e1defc4ff
|
1037 1038 1039 |
printk(KERN_ERR "logical block size: %d ", bdev_logical_block_size(bdev)); |
1da177e4c
|
1040 1041 1042 1043 |
dump_stack(); return NULL; } |
676ce6d5c
|
1044 1045 1046 |
for (;;) { struct buffer_head *bh; int ret; |
1da177e4c
|
1047 1048 1049 1050 |
bh = __find_get_block(bdev, block, size); if (bh) return bh; |
676ce6d5c
|
1051 1052 1053 1054 1055 1056 |
ret = grow_buffers(bdev, block, size); if (ret < 0) return NULL; if (ret == 0) free_more_memory(); |
1da177e4c
|
1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 |
} } /* * The relationship between dirty buffers and dirty pages: * * Whenever a page has any dirty buffers, the page's dirty bit is set, and * the page is tagged dirty in its radix tree. * * At all times, the dirtiness of the buffers represents the dirtiness of * subsections of the page. If the page has buffers, the page dirty bit is * merely a hint about the true dirty state. * * When a page is set dirty in its entirety, all its buffers are marked dirty * (if the page has buffers). * * When a buffer is marked dirty, its page is dirtied, but the page's other * buffers are not. * * Also. When blockdev buffers are explicitly read with bread(), they * individually become uptodate. But their backing page remains not * uptodate - even if all of its buffers are uptodate. A subsequent * block_read_full_page() against that page will discover all the uptodate * buffers, will set the page uptodate and will perform no I/O. */ /** * mark_buffer_dirty - mark a buffer_head as needing writeout |
67be2dd1b
|
1085 |
* @bh: the buffer_head to mark dirty |
1da177e4c
|
1086 1087 1088 1089 1090 1091 1092 |
* * mark_buffer_dirty() will set the dirty bit against the buffer, then set its * backing page dirty, then tag the page as dirty in its address_space's radix * tree and then attach the address_space's inode to its superblock's dirty * inode list. * * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, |
250df6ed2
|
1093 |
* mapping->tree_lock and mapping->host->i_lock. |
1da177e4c
|
1094 |
*/ |
fc9b52cd8
|
1095 |
void mark_buffer_dirty(struct buffer_head *bh) |
1da177e4c
|
1096 |
{ |
787d2214c
|
1097 |
WARN_ON_ONCE(!buffer_uptodate(bh)); |
1be62dc19
|
1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 |
/* * Very *carefully* optimize the it-is-already-dirty case. * * Don't let the final "is it dirty" escape to before we * perhaps modified the buffer. */ if (buffer_dirty(bh)) { smp_mb(); if (buffer_dirty(bh)) return; } |
a8e7d49aa
|
1110 1111 |
if (!test_set_buffer_dirty(bh)) { struct page *page = bh->b_page; |
8e9d78ede
|
1112 1113 1114 1115 1116 |
if (!TestSetPageDirty(page)) { struct address_space *mapping = page_mapping(page); if (mapping) __set_page_dirty(page, mapping, 0); } |
a8e7d49aa
|
1117 |
} |
1da177e4c
|
1118 |
} |
1fe72eaa0
|
1119 |
EXPORT_SYMBOL(mark_buffer_dirty); |
1da177e4c
|
1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 |
/* * Decrement a buffer_head's reference count. If all buffers against a page * have zero reference count, are clean and unlocked, and if the page is clean * and unlocked then try_to_free_buffers() may strip the buffers from the page * in preparation for freeing it (sometimes, rarely, buffers are removed from * a page but it ends up not being freed, and buffers may later be reattached). */ void __brelse(struct buffer_head * buf) { if (atomic_read(&buf->b_count)) { put_bh(buf); return; } |
5c752ad9f
|
1134 1135 |
WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer "); |
1da177e4c
|
1136 |
} |
1fe72eaa0
|
1137 |
EXPORT_SYMBOL(__brelse); |
1da177e4c
|
1138 1139 1140 1141 1142 1143 1144 1145 |
/* * bforget() is like brelse(), except it discards any * potentially dirty data. */ void __bforget(struct buffer_head *bh) { clear_buffer_dirty(bh); |
535ee2fbf
|
1146 |
if (bh->b_assoc_map) { |
1da177e4c
|
1147 1148 1149 1150 |
struct address_space *buffer_mapping = bh->b_page->mapping; spin_lock(&buffer_mapping->private_lock); list_del_init(&bh->b_assoc_buffers); |
58ff407be
|
1151 |
bh->b_assoc_map = NULL; |
1da177e4c
|
1152 1153 1154 1155 |
spin_unlock(&buffer_mapping->private_lock); } __brelse(bh); } |
1fe72eaa0
|
1156 |
EXPORT_SYMBOL(__bforget); |
1da177e4c
|
1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 |
static struct buffer_head *__bread_slow(struct buffer_head *bh) { lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); return bh; } else { get_bh(bh); bh->b_end_io = end_buffer_read_sync; submit_bh(READ, bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return bh; } brelse(bh); return NULL; } /* * Per-cpu buffer LRU implementation. To reduce the cost of __find_get_block(). * The bhs[] array is sorted - newest buffer is at bhs[0]. Buffers have their * refcount elevated by one when they're in an LRU. A buffer can only appear * once in a particular CPU's LRU. A single buffer can be present in multiple * CPU's LRUs at the same time. * * This is a transparent caching front-end to sb_bread(), sb_getblk() and * sb_find_get_block(). * * The LRUs themselves only need locking against invalidate_bh_lrus. We use * a local interrupt disable for that. */ #define BH_LRU_SIZE 8 struct bh_lru { struct buffer_head *bhs[BH_LRU_SIZE]; }; static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }}; #ifdef CONFIG_SMP #define bh_lru_lock() local_irq_disable() #define bh_lru_unlock() local_irq_enable() #else #define bh_lru_lock() preempt_disable() #define bh_lru_unlock() preempt_enable() #endif static inline void check_irqs_on(void) { #ifdef irqs_disabled BUG_ON(irqs_disabled()); #endif } /* * The LRU management algorithm is dopey-but-simple. Sorry. */ static void bh_lru_install(struct buffer_head *bh) { struct buffer_head *evictee = NULL; |
1da177e4c
|
1219 1220 1221 |
check_irqs_on(); bh_lru_lock(); |
c7b92516a
|
1222 |
if (__this_cpu_read(bh_lrus.bhs[0]) != bh) { |
1da177e4c
|
1223 1224 1225 1226 1227 1228 1229 |
struct buffer_head *bhs[BH_LRU_SIZE]; int in; int out = 0; get_bh(bh); bhs[out++] = bh; for (in = 0; in < BH_LRU_SIZE; in++) { |
c7b92516a
|
1230 1231 |
struct buffer_head *bh2 = __this_cpu_read(bh_lrus.bhs[in]); |
1da177e4c
|
1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 |
if (bh2 == bh) { __brelse(bh2); } else { if (out >= BH_LRU_SIZE) { BUG_ON(evictee != NULL); evictee = bh2; } else { bhs[out++] = bh2; } } } while (out < BH_LRU_SIZE) bhs[out++] = NULL; |
c7b92516a
|
1246 |
memcpy(__this_cpu_ptr(&bh_lrus.bhs), bhs, sizeof(bhs)); |
1da177e4c
|
1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 |
} bh_lru_unlock(); if (evictee) __brelse(evictee); } /* * Look up the bh in this cpu's LRU. If it's there, move it to the head. */ |
858119e15
|
1257 |
static struct buffer_head * |
3991d3bd1
|
1258 |
lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size) |
1da177e4c
|
1259 1260 |
{ struct buffer_head *ret = NULL; |
3991d3bd1
|
1261 |
unsigned int i; |
1da177e4c
|
1262 1263 1264 |
check_irqs_on(); bh_lru_lock(); |
1da177e4c
|
1265 |
for (i = 0; i < BH_LRU_SIZE; i++) { |
c7b92516a
|
1266 |
struct buffer_head *bh = __this_cpu_read(bh_lrus.bhs[i]); |
1da177e4c
|
1267 1268 1269 1270 1271 |
if (bh && bh->b_bdev == bdev && bh->b_blocknr == block && bh->b_size == size) { if (i) { while (i) { |
c7b92516a
|
1272 1273 |
__this_cpu_write(bh_lrus.bhs[i], __this_cpu_read(bh_lrus.bhs[i - 1])); |
1da177e4c
|
1274 1275 |
i--; } |
c7b92516a
|
1276 |
__this_cpu_write(bh_lrus.bhs[0], bh); |
1da177e4c
|
1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 |
} get_bh(bh); ret = bh; break; } } bh_lru_unlock(); return ret; } /* * Perform a pagecache lookup for the matching buffer. If it's there, refresh * it in the LRU and mark it as accessed. If it is not present then return * NULL */ struct buffer_head * |
3991d3bd1
|
1293 |
__find_get_block(struct block_device *bdev, sector_t block, unsigned size) |
1da177e4c
|
1294 1295 1296 1297 |
{ struct buffer_head *bh = lookup_bh_lru(bdev, block, size); if (bh == NULL) { |
385fd4c59
|
1298 |
bh = __find_get_block_slow(bdev, block); |
1da177e4c
|
1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 |
if (bh) bh_lru_install(bh); } if (bh) touch_buffer(bh); return bh; } EXPORT_SYMBOL(__find_get_block); /* * __getblk will locate (and, if necessary, create) the buffer_head * which corresponds to the passed block_device, block and size. The * returned buffer has its reference count incremented. * |
1da177e4c
|
1313 1314 1315 1316 |
* __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() * attempt is failing. FIXME, perhaps? */ struct buffer_head * |
3991d3bd1
|
1317 |
__getblk(struct block_device *bdev, sector_t block, unsigned size) |
1da177e4c
|
1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 |
{ struct buffer_head *bh = __find_get_block(bdev, block, size); might_sleep(); if (bh == NULL) bh = __getblk_slow(bdev, block, size); return bh; } EXPORT_SYMBOL(__getblk); /* * Do async read-ahead on a buffer.. */ |
3991d3bd1
|
1331 |
void __breadahead(struct block_device *bdev, sector_t block, unsigned size) |
1da177e4c
|
1332 1333 |
{ struct buffer_head *bh = __getblk(bdev, block, size); |
a3e713b5f
|
1334 1335 1336 1337 |
if (likely(bh)) { ll_rw_block(READA, 1, &bh); brelse(bh); } |
1da177e4c
|
1338 1339 1340 1341 1342 |
} EXPORT_SYMBOL(__breadahead); /** * __bread() - reads a specified block and returns the bh |
67be2dd1b
|
1343 |
* @bdev: the block_device to read from |
1da177e4c
|
1344 1345 1346 1347 1348 1349 1350 |
* @block: number of block * @size: size (in bytes) to read * * Reads a specified block, and returns buffer head that contains it. * It returns NULL if the block was unreadable. */ struct buffer_head * |
3991d3bd1
|
1351 |
__bread(struct block_device *bdev, sector_t block, unsigned size) |
1da177e4c
|
1352 1353 |
{ struct buffer_head *bh = __getblk(bdev, block, size); |
a3e713b5f
|
1354 |
if (likely(bh) && !buffer_uptodate(bh)) |
1da177e4c
|
1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 |
bh = __bread_slow(bh); return bh; } EXPORT_SYMBOL(__bread); /* * invalidate_bh_lrus() is called rarely - but not only at unmount. * This doesn't race because it runs in each cpu either in irq * or with preempt disabled. */ static void invalidate_bh_lru(void *arg) { struct bh_lru *b = &get_cpu_var(bh_lrus); int i; for (i = 0; i < BH_LRU_SIZE; i++) { brelse(b->bhs[i]); b->bhs[i] = NULL; } put_cpu_var(bh_lrus); } |
42be35d03
|
1376 1377 1378 1379 1380 |
static bool has_bh_in_lru(int cpu, void *dummy) { struct bh_lru *b = per_cpu_ptr(&bh_lrus, cpu); int i; |
1da177e4c
|
1381 |
|
42be35d03
|
1382 1383 1384 1385 1386 1387 1388 |
for (i = 0; i < BH_LRU_SIZE; i++) { if (b->bhs[i]) return 1; } return 0; } |
f9a14399a
|
1389 |
void invalidate_bh_lrus(void) |
1da177e4c
|
1390 |
{ |
42be35d03
|
1391 |
on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1, GFP_KERNEL); |
1da177e4c
|
1392 |
} |
9db5579be
|
1393 |
EXPORT_SYMBOL_GPL(invalidate_bh_lrus); |
1da177e4c
|
1394 1395 1396 1397 1398 |
void set_bh_page(struct buffer_head *bh, struct page *page, unsigned long offset) { bh->b_page = page; |
e827f9235
|
1399 |
BUG_ON(offset >= PAGE_SIZE); |
1da177e4c
|
1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 |
if (PageHighMem(page)) /* * This catches illegal uses and preserves the offset: */ bh->b_data = (char *)(0 + offset); else bh->b_data = page_address(page) + offset; } EXPORT_SYMBOL(set_bh_page); /* * Called when truncating a buffer on a page completely. */ |
858119e15
|
1413 |
static void discard_buffer(struct buffer_head * bh) |
1da177e4c
|
1414 1415 1416 1417 1418 1419 1420 1421 |
{ lock_buffer(bh); clear_buffer_dirty(bh); bh->b_bdev = NULL; clear_buffer_mapped(bh); clear_buffer_req(bh); clear_buffer_new(bh); clear_buffer_delay(bh); |
33a266dda
|
1422 |
clear_buffer_unwritten(bh); |
1da177e4c
|
1423 1424 1425 1426 |
unlock_buffer(bh); } /** |
814e1d25a
|
1427 |
* block_invalidatepage - invalidate part or all of a buffer-backed page |
1da177e4c
|
1428 1429 1430 1431 1432 |
* * @page: the page which is affected * @offset: the index of the truncation point * * block_invalidatepage() is called when all or part of the page has become |
814e1d25a
|
1433 |
* invalidated by a truncate operation. |
1da177e4c
|
1434 1435 1436 1437 1438 1439 1440 |
* * block_invalidatepage() does not have to release all buffers, but it must * ensure that no dirty buffer is left outside @offset and that no I/O * is underway against any of the blocks which are outside the truncation * point. Because the caller is about to free (and possibly reuse) those * blocks on-disk. */ |
2ff28e22b
|
1441 |
void block_invalidatepage(struct page *page, unsigned long offset) |
1da177e4c
|
1442 1443 1444 |
{ struct buffer_head *head, *bh, *next; unsigned int curr_off = 0; |
1da177e4c
|
1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 |
BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) goto out; head = page_buffers(page); bh = head; do { unsigned int next_off = curr_off + bh->b_size; next = bh->b_this_page; /* * is this block fully invalidated? */ if (offset <= curr_off) discard_buffer(bh); curr_off = next_off; bh = next; } while (bh != head); /* * We release buffers only if the entire page is being invalidated. * The get_block cached value has been unconditionally invalidated, * so real IO is not possible anymore. */ if (offset == 0) |
2ff28e22b
|
1471 |
try_to_release_page(page, 0); |
1da177e4c
|
1472 |
out: |
2ff28e22b
|
1473 |
return; |
1da177e4c
|
1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 |
} EXPORT_SYMBOL(block_invalidatepage); /* * We attach and possibly dirty the buffers atomically wrt * __set_page_dirty_buffers() via private_lock. try_to_free_buffers * is already excluded via the page lock. */ void create_empty_buffers(struct page *page, unsigned long blocksize, unsigned long b_state) { struct buffer_head *bh, *head, *tail; head = alloc_page_buffers(page, blocksize, 1); bh = head; do { bh->b_state |= b_state; tail = bh; bh = bh->b_this_page; } while (bh); tail->b_this_page = head; spin_lock(&page->mapping->private_lock); if (PageUptodate(page) || PageDirty(page)) { bh = head; do { if (PageDirty(page)) set_buffer_dirty(bh); if (PageUptodate(page)) set_buffer_uptodate(bh); bh = bh->b_this_page; } while (bh != head); } attach_page_buffers(page, head); spin_unlock(&page->mapping->private_lock); } EXPORT_SYMBOL(create_empty_buffers); /* * We are taking a block for data and we don't want any output from any * buffer-cache aliases starting from return from that function and * until the moment when something will explicitly mark the buffer * dirty (hopefully that will not happen until we will free that block ;-) * We don't even need to mark it not-uptodate - nobody can expect * anything from a newly allocated buffer anyway. We used to used * unmap_buffer() for such invalidation, but that was wrong. We definitely * don't want to mark the alias unmapped, for example - it would confuse * anyone who might pick it with bread() afterwards... * * Also.. Note that bforget() doesn't lock the buffer. So there can * be writeout I/O going on against recently-freed buffers. We don't * wait on that I/O in bforget() - it's more efficient to wait on the I/O * only if we really need to. That happens here. */ void unmap_underlying_metadata(struct block_device *bdev, sector_t block) { struct buffer_head *old_bh; might_sleep(); |
385fd4c59
|
1533 |
old_bh = __find_get_block_slow(bdev, block); |
1da177e4c
|
1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 |
if (old_bh) { clear_buffer_dirty(old_bh); wait_on_buffer(old_bh); clear_buffer_req(old_bh); __brelse(old_bh); } } EXPORT_SYMBOL(unmap_underlying_metadata); /* * NOTE! All mapped/uptodate combinations are valid: * * Mapped Uptodate Meaning * * No No "unknown" - must do get_block() * No Yes "hole" - zero-filled * Yes No "allocated" - allocated on disk, not read in * Yes Yes "valid" - allocated and up-to-date in memory. * * "Dirty" is valid only with the last case (mapped+uptodate). */ /* * While block_write_full_page is writing back the dirty buffers under * the page lock, whoever dirtied the buffers may decide to clean them * again at any time. We handle that by only looking at the buffer * state inside lock_buffer(). * * If block_write_full_page() is called for regular writeback * (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a * locked buffer. This only can happen if someone has written the buffer * directly, with submit_bh(). At the address_space level PageWriteback * prevents this contention from occurring. |
6e34eeddf
|
1567 1568 |
* * If block_write_full_page() is called with wbc->sync_mode == |
721a9602e
|
1569 1570 |
* WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this * causes the writes to be flagged as synchronous writes. |
1da177e4c
|
1571 1572 |
*/ static int __block_write_full_page(struct inode *inode, struct page *page, |
35c80d5f4
|
1573 1574 |
get_block_t *get_block, struct writeback_control *wbc, bh_end_io_t *handler) |
1da177e4c
|
1575 1576 1577 1578 |
{ int err; sector_t block; sector_t last_block; |
f0fbd5fc0
|
1579 |
struct buffer_head *bh, *head; |
b0cf2321c
|
1580 |
const unsigned blocksize = 1 << inode->i_blkbits; |
1da177e4c
|
1581 |
int nr_underway = 0; |
6e34eeddf
|
1582 |
int write_op = (wbc->sync_mode == WB_SYNC_ALL ? |
721a9602e
|
1583 |
WRITE_SYNC : WRITE); |
1da177e4c
|
1584 1585 1586 1587 1588 1589 |
BUG_ON(!PageLocked(page)); last_block = (i_size_read(inode) - 1) >> inode->i_blkbits; if (!page_has_buffers(page)) { |
b0cf2321c
|
1590 |
create_empty_buffers(page, blocksize, |
1da177e4c
|
1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 |
(1 << BH_Dirty)|(1 << BH_Uptodate)); } /* * Be very careful. We have no exclusion from __set_page_dirty_buffers * here, and the (potentially unmapped) buffers may become dirty at * any time. If a buffer becomes dirty here after we've inspected it * then we just miss that fact, and the page stays dirty. * * Buffers outside i_size may be dirtied by __set_page_dirty_buffers; * handle that here by just cleaning them. */ |
54b21a799
|
1603 |
block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
1da177e4c
|
1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 |
head = page_buffers(page); bh = head; /* * Get all the dirty buffers mapped to disk addresses and * handle any aliases from the underlying blockdev's mapping. */ do { if (block > last_block) { /* * mapped buffers outside i_size will occur, because * this page can be outside i_size when there is a * truncate in progress. */ /* * The buffer was zeroed by block_write_full_page() */ clear_buffer_dirty(bh); set_buffer_uptodate(bh); |
29a814d2e
|
1623 1624 |
} else if ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh)) { |
b0cf2321c
|
1625 |
WARN_ON(bh->b_size != blocksize); |
1da177e4c
|
1626 1627 1628 |
err = get_block(inode, block, bh, 1); if (err) goto recover; |
29a814d2e
|
1629 |
clear_buffer_delay(bh); |
1da177e4c
|
1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 |
if (buffer_new(bh)) { /* blockdev mappings never come here */ clear_buffer_new(bh); unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); } } bh = bh->b_this_page; block++; } while (bh != head); do { |
1da177e4c
|
1642 1643 1644 1645 1646 |
if (!buffer_mapped(bh)) continue; /* * If it's a fully non-blocking write attempt and we cannot * lock the buffer then redirty the page. Note that this can |
5b0830cb9
|
1647 1648 1649 |
* potentially cause a busy-wait loop from writeback threads * and kswapd activity, but those code paths have their own * higher-level throttling. |
1da177e4c
|
1650 |
*/ |
1b430beee
|
1651 |
if (wbc->sync_mode != WB_SYNC_NONE) { |
1da177e4c
|
1652 |
lock_buffer(bh); |
ca5de404f
|
1653 |
} else if (!trylock_buffer(bh)) { |
1da177e4c
|
1654 1655 1656 1657 |
redirty_page_for_writepage(wbc, page); continue; } if (test_clear_buffer_dirty(bh)) { |
35c80d5f4
|
1658 |
mark_buffer_async_write_endio(bh, handler); |
1da177e4c
|
1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 |
} else { unlock_buffer(bh); } } while ((bh = bh->b_this_page) != head); /* * The page and its buffers are protected by PageWriteback(), so we can * drop the bh refcounts early. */ BUG_ON(PageWriteback(page)); set_page_writeback(page); |
1da177e4c
|
1670 1671 1672 1673 |
do { struct buffer_head *next = bh->b_this_page; if (buffer_async_write(bh)) { |
a64c8610b
|
1674 |
submit_bh(write_op, bh); |
1da177e4c
|
1675 1676 |
nr_underway++; } |
1da177e4c
|
1677 1678 |
bh = next; } while (bh != head); |
05937baae
|
1679 |
unlock_page(page); |
1da177e4c
|
1680 1681 1682 1683 1684 1685 1686 1687 1688 |
err = 0; done: if (nr_underway == 0) { /* * The page was marked dirty, but the buffers were * clean. Someone wrote them back by hand with * ll_rw_block/submit_bh. A rare case. */ |
1da177e4c
|
1689 |
end_page_writeback(page); |
3d67f2d7c
|
1690 |
|
1da177e4c
|
1691 1692 1693 1694 |
/* * The page and buffer_heads can be released at any time from * here on. */ |
1da177e4c
|
1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 |
} return err; recover: /* * ENOSPC, or some other error. We may already have added some * blocks to the file, so we need to write these out to avoid * exposing stale data. * The page is currently locked and not marked for writeback */ bh = head; /* Recovery: lock and submit the mapped buffers */ do { |
29a814d2e
|
1708 1709 |
if (buffer_mapped(bh) && buffer_dirty(bh) && !buffer_delay(bh)) { |
1da177e4c
|
1710 |
lock_buffer(bh); |
35c80d5f4
|
1711 |
mark_buffer_async_write_endio(bh, handler); |
1da177e4c
|
1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 |
} else { /* * The buffer may have been set dirty during * attachment to a dirty page. */ clear_buffer_dirty(bh); } } while ((bh = bh->b_this_page) != head); SetPageError(page); BUG_ON(PageWriteback(page)); |
7e4c3690b
|
1722 |
mapping_set_error(page->mapping, err); |
1da177e4c
|
1723 |
set_page_writeback(page); |
1da177e4c
|
1724 1725 1726 1727 |
do { struct buffer_head *next = bh->b_this_page; if (buffer_async_write(bh)) { clear_buffer_dirty(bh); |
a64c8610b
|
1728 |
submit_bh(write_op, bh); |
1da177e4c
|
1729 1730 |
nr_underway++; } |
1da177e4c
|
1731 1732 |
bh = next; } while (bh != head); |
ffda9d302
|
1733 |
unlock_page(page); |
1da177e4c
|
1734 1735 |
goto done; } |
afddba49d
|
1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 |
/* * If a page has any new buffers, zero them out here, and mark them uptodate * and dirty so they'll be written out (in order to prevent uninitialised * block data from leaking). And clear the new bit. */ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) { unsigned int block_start, block_end; struct buffer_head *head, *bh; BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) return; bh = head = page_buffers(page); block_start = 0; do { block_end = block_start + bh->b_size; if (buffer_new(bh)) { if (block_end > from && block_start < to) { if (!PageUptodate(page)) { unsigned start, size; start = max(from, block_start); size = min(to, block_end) - start; |
eebd2aa35
|
1762 |
zero_user(page, start, size); |
afddba49d
|
1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 |
set_buffer_uptodate(bh); } clear_buffer_new(bh); mark_buffer_dirty(bh); } } block_start = block_end; bh = bh->b_this_page; } while (bh != head); } EXPORT_SYMBOL(page_zero_new_buffers); |
ebdec241d
|
1776 |
int __block_write_begin(struct page *page, loff_t pos, unsigned len, |
6e1db88d5
|
1777 |
get_block_t *get_block) |
1da177e4c
|
1778 |
{ |
ebdec241d
|
1779 1780 |
unsigned from = pos & (PAGE_CACHE_SIZE - 1); unsigned to = from + len; |
6e1db88d5
|
1781 |
struct inode *inode = page->mapping->host; |
1da177e4c
|
1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 |
unsigned block_start, block_end; sector_t block; int err = 0; unsigned blocksize, bbits; struct buffer_head *bh, *head, *wait[2], **wait_bh=wait; BUG_ON(!PageLocked(page)); BUG_ON(from > PAGE_CACHE_SIZE); BUG_ON(to > PAGE_CACHE_SIZE); BUG_ON(from > to); blocksize = 1 << inode->i_blkbits; if (!page_has_buffers(page)) create_empty_buffers(page, blocksize, 0); head = page_buffers(page); bbits = inode->i_blkbits; block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); for(bh = head, block_start = 0; bh != head || !block_start; block++, block_start=block_end, bh = bh->b_this_page) { block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (PageUptodate(page)) { if (!buffer_uptodate(bh)) set_buffer_uptodate(bh); } continue; } if (buffer_new(bh)) clear_buffer_new(bh); if (!buffer_mapped(bh)) { |
b0cf2321c
|
1814 |
WARN_ON(bh->b_size != blocksize); |
1da177e4c
|
1815 1816 |
err = get_block(inode, block, bh, 1); if (err) |
f3ddbdc62
|
1817 |
break; |
1da177e4c
|
1818 |
if (buffer_new(bh)) { |
1da177e4c
|
1819 1820 1821 |
unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); if (PageUptodate(page)) { |
637aff46f
|
1822 |
clear_buffer_new(bh); |
1da177e4c
|
1823 |
set_buffer_uptodate(bh); |
637aff46f
|
1824 |
mark_buffer_dirty(bh); |
1da177e4c
|
1825 1826 |
continue; } |
eebd2aa35
|
1827 1828 1829 1830 |
if (block_end > to || block_start < from) zero_user_segments(page, to, block_end, block_start, from); |
1da177e4c
|
1831 1832 1833 1834 1835 1836 1837 1838 1839 |
continue; } } if (PageUptodate(page)) { if (!buffer_uptodate(bh)) set_buffer_uptodate(bh); continue; } if (!buffer_uptodate(bh) && !buffer_delay(bh) && |
33a266dda
|
1840 |
!buffer_unwritten(bh) && |
1da177e4c
|
1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 |
(block_start < from || block_end > to)) { ll_rw_block(READ, 1, &bh); *wait_bh++=bh; } } /* * If we issued read requests - let them complete. */ while(wait_bh > wait) { wait_on_buffer(*--wait_bh); if (!buffer_uptodate(*wait_bh)) |
f3ddbdc62
|
1852 |
err = -EIO; |
1da177e4c
|
1853 |
} |
f9f07b6c1
|
1854 |
if (unlikely(err)) |
afddba49d
|
1855 |
page_zero_new_buffers(page, from, to); |
1da177e4c
|
1856 1857 |
return err; } |
ebdec241d
|
1858 |
EXPORT_SYMBOL(__block_write_begin); |
1da177e4c
|
1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 |
static int __block_commit_write(struct inode *inode, struct page *page, unsigned from, unsigned to) { unsigned block_start, block_end; int partial = 0; unsigned blocksize; struct buffer_head *bh, *head; blocksize = 1 << inode->i_blkbits; for(bh = head = page_buffers(page), block_start = 0; bh != head || !block_start; block_start=block_end, bh = bh->b_this_page) { block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (!buffer_uptodate(bh)) partial = 1; } else { set_buffer_uptodate(bh); mark_buffer_dirty(bh); } |
afddba49d
|
1881 |
clear_buffer_new(bh); |
1da177e4c
|
1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 |
} /* * If this is a partial write which happened to make all buffers * uptodate then we can optimize away a bogus readpage() for * the next read(). Here we 'discover' whether the page went * uptodate as a result of this (potentially partial) write. */ if (!partial) SetPageUptodate(page); return 0; } /* |
155130a4f
|
1896 1897 1898 |
* block_write_begin takes care of the basic task of block allocation and * bringing partial write blocks uptodate first. * |
7bb46a673
|
1899 |
* The filesystem needs to handle block truncation upon failure. |
afddba49d
|
1900 |
*/ |
155130a4f
|
1901 1902 |
int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, get_block_t *get_block) |
afddba49d
|
1903 |
{ |
6e1db88d5
|
1904 |
pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
afddba49d
|
1905 |
struct page *page; |
6e1db88d5
|
1906 |
int status; |
afddba49d
|
1907 |
|
6e1db88d5
|
1908 1909 1910 |
page = grab_cache_page_write_begin(mapping, index, flags); if (!page) return -ENOMEM; |
afddba49d
|
1911 |
|
6e1db88d5
|
1912 |
status = __block_write_begin(page, pos, len, get_block); |
afddba49d
|
1913 |
if (unlikely(status)) { |
6e1db88d5
|
1914 1915 1916 |
unlock_page(page); page_cache_release(page); page = NULL; |
afddba49d
|
1917 |
} |
6e1db88d5
|
1918 |
*pagep = page; |
afddba49d
|
1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 |
return status; } EXPORT_SYMBOL(block_write_begin); int block_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = mapping->host; unsigned start; start = pos & (PAGE_CACHE_SIZE - 1); if (unlikely(copied < len)) { /* * The buffers that were written will now be uptodate, so we * don't have to worry about a readpage reading them and * overwriting a partial write. However if we have encountered * a short write and only partially written into a buffer, it * will not be marked uptodate, so a readpage might come in and * destroy our partial write. * * Do the simplest thing, and just treat any short write to a * non uptodate page as a zero-length write, and force the * caller to redo the whole thing. */ if (!PageUptodate(page)) copied = 0; page_zero_new_buffers(page, start+copied, start+len); } flush_dcache_page(page); /* This could be a short (even 0-length) commit */ __block_commit_write(inode, page, start, start+copied); return copied; } EXPORT_SYMBOL(block_write_end); int generic_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = mapping->host; |
c7d206b33
|
1964 |
int i_size_changed = 0; |
afddba49d
|
1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 |
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); /* * No need to use i_size_read() here, the i_size * cannot change under us because we hold i_mutex. * * But it's important to update i_size while still holding page lock: * page writeout could otherwise come in and zero beyond i_size. */ if (pos+copied > inode->i_size) { i_size_write(inode, pos+copied); |
c7d206b33
|
1977 |
i_size_changed = 1; |
afddba49d
|
1978 1979 1980 1981 |
} unlock_page(page); page_cache_release(page); |
c7d206b33
|
1982 1983 1984 1985 1986 1987 1988 1989 |
/* * Don't mark the inode dirty under page lock. First, it unnecessarily * makes the holding time of page lock longer. Second, it forces lock * ordering of page lock and transaction start for journaling * filesystems. */ if (i_size_changed) mark_inode_dirty(inode); |
afddba49d
|
1990 1991 1992 1993 1994 |
return copied; } EXPORT_SYMBOL(generic_write_end); /* |
8ab22b9ab
|
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 |
* block_is_partially_uptodate checks whether buffers within a page are * uptodate or not. * * Returns true if all buffers which correspond to a file portion * we want to read are uptodate. */ int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, unsigned long from) { struct inode *inode = page->mapping->host; unsigned block_start, block_end, blocksize; unsigned to; struct buffer_head *bh, *head; int ret = 1; if (!page_has_buffers(page)) return 0; blocksize = 1 << inode->i_blkbits; to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count); to = from + to; if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize) return 0; head = page_buffers(page); bh = head; block_start = 0; do { block_end = block_start + blocksize; if (block_end > from && block_start < to) { if (!buffer_uptodate(bh)) { ret = 0; break; } if (block_end >= to) break; } block_start = block_end; bh = bh->b_this_page; } while (bh != head); return ret; } EXPORT_SYMBOL(block_is_partially_uptodate); /* |
1da177e4c
|
2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 |
* Generic "read page" function for block devices that have the normal * get_block functionality. This is most of the block device filesystems. * Reads the page asynchronously --- the unlock_buffer() and * set/clear_buffer_uptodate() functions propagate buffer state into the * page struct once IO has completed. */ int block_read_full_page(struct page *page, get_block_t *get_block) { struct inode *inode = page->mapping->host; sector_t iblock, lblock; struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; unsigned int blocksize; int nr, i; int fully_mapped = 1; |
cd7619d6b
|
2055 |
BUG_ON(!PageLocked(page)); |
1da177e4c
|
2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 |
blocksize = 1 << inode->i_blkbits; if (!page_has_buffers(page)) create_empty_buffers(page, blocksize, 0); head = page_buffers(page); iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits; bh = head; nr = 0; i = 0; do { if (buffer_uptodate(bh)) continue; if (!buffer_mapped(bh)) { |
c64610ba5
|
2072 |
int err = 0; |
1da177e4c
|
2073 2074 |
fully_mapped = 0; if (iblock < lblock) { |
b0cf2321c
|
2075 |
WARN_ON(bh->b_size != blocksize); |
c64610ba5
|
2076 2077 |
err = get_block(inode, iblock, bh, 0); if (err) |
1da177e4c
|
2078 2079 2080 |
SetPageError(page); } if (!buffer_mapped(bh)) { |
eebd2aa35
|
2081 |
zero_user(page, i * blocksize, blocksize); |
c64610ba5
|
2082 2083 |
if (!err) set_buffer_uptodate(bh); |
1da177e4c
|
2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 |
continue; } /* * get_block() might have updated the buffer * synchronously */ if (buffer_uptodate(bh)) continue; } arr[nr++] = bh; } while (i++, iblock++, (bh = bh->b_this_page) != head); if (fully_mapped) SetPageMappedToDisk(page); if (!nr) { /* * All buffers are uptodate - we can set the page uptodate * as well. But not if get_block() returned an error. */ if (!PageError(page)) SetPageUptodate(page); unlock_page(page); return 0; } /* Stage two: lock the buffers */ for (i = 0; i < nr; i++) { bh = arr[i]; lock_buffer(bh); mark_buffer_async_read(bh); } /* * Stage 3: start the IO. Check for uptodateness * inside the buffer lock in case another process reading * the underlying blockdev brought it uptodate (the sct fix). */ for (i = 0; i < nr; i++) { bh = arr[i]; if (buffer_uptodate(bh)) end_buffer_async_read(bh, 1); else submit_bh(READ, bh); } return 0; } |
1fe72eaa0
|
2131 |
EXPORT_SYMBOL(block_read_full_page); |
1da177e4c
|
2132 2133 |
/* utility function for filesystems that need to do work on expanding |
89e107877
|
2134 |
* truncates. Uses filesystem pagecache writes to allow the filesystem to |
1da177e4c
|
2135 2136 |
* deal with the hole. */ |
89e107877
|
2137 |
int generic_cont_expand_simple(struct inode *inode, loff_t size) |
1da177e4c
|
2138 2139 2140 |
{ struct address_space *mapping = inode->i_mapping; struct page *page; |
89e107877
|
2141 |
void *fsdata; |
1da177e4c
|
2142 |
int err; |
c08d3b0e3
|
2143 2144 |
err = inode_newsize_ok(inode, size); if (err) |
1da177e4c
|
2145 |
goto out; |
89e107877
|
2146 2147 2148 2149 |
err = pagecache_write_begin(NULL, mapping, size, 0, AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND, &page, &fsdata); if (err) |
05eb0b51f
|
2150 |
goto out; |
05eb0b51f
|
2151 |
|
89e107877
|
2152 2153 |
err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata); BUG_ON(err > 0); |
05eb0b51f
|
2154 |
|
1da177e4c
|
2155 2156 2157 |
out: return err; } |
1fe72eaa0
|
2158 |
EXPORT_SYMBOL(generic_cont_expand_simple); |
1da177e4c
|
2159 |
|
f1e3af72c
|
2160 2161 |
static int cont_expand_zero(struct file *file, struct address_space *mapping, loff_t pos, loff_t *bytes) |
1da177e4c
|
2162 |
{ |
1da177e4c
|
2163 |
struct inode *inode = mapping->host; |
1da177e4c
|
2164 |
unsigned blocksize = 1 << inode->i_blkbits; |
89e107877
|
2165 2166 2167 2168 2169 2170 |
struct page *page; void *fsdata; pgoff_t index, curidx; loff_t curpos; unsigned zerofrom, offset, len; int err = 0; |
1da177e4c
|
2171 |
|
89e107877
|
2172 2173 2174 2175 2176 |
index = pos >> PAGE_CACHE_SHIFT; offset = pos & ~PAGE_CACHE_MASK; while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) { zerofrom = curpos & ~PAGE_CACHE_MASK; |
1da177e4c
|
2177 2178 2179 2180 |
if (zerofrom & (blocksize-1)) { *bytes |= (blocksize-1); (*bytes)++; } |
89e107877
|
2181 |
len = PAGE_CACHE_SIZE - zerofrom; |
1da177e4c
|
2182 |
|
89e107877
|
2183 2184 2185 2186 2187 |
err = pagecache_write_begin(file, mapping, curpos, len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); if (err) goto out; |
eebd2aa35
|
2188 |
zero_user(page, zerofrom, len); |
89e107877
|
2189 2190 2191 2192 2193 2194 |
err = pagecache_write_end(file, mapping, curpos, len, len, page, fsdata); if (err < 0) goto out; BUG_ON(err != len); err = 0; |
061e97469
|
2195 2196 |
balance_dirty_pages_ratelimited(mapping); |
89e107877
|
2197 |
} |
1da177e4c
|
2198 |
|
89e107877
|
2199 2200 2201 |
/* page covers the boundary, find the boundary offset */ if (index == curidx) { zerofrom = curpos & ~PAGE_CACHE_MASK; |
1da177e4c
|
2202 |
/* if we will expand the thing last block will be filled */ |
89e107877
|
2203 2204 2205 2206 |
if (offset <= zerofrom) { goto out; } if (zerofrom & (blocksize-1)) { |
1da177e4c
|
2207 2208 2209 |
*bytes |= (blocksize-1); (*bytes)++; } |
89e107877
|
2210 |
len = offset - zerofrom; |
1da177e4c
|
2211 |
|
89e107877
|
2212 2213 2214 2215 2216 |
err = pagecache_write_begin(file, mapping, curpos, len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); if (err) goto out; |
eebd2aa35
|
2217 |
zero_user(page, zerofrom, len); |
89e107877
|
2218 2219 2220 2221 2222 2223 |
err = pagecache_write_end(file, mapping, curpos, len, len, page, fsdata); if (err < 0) goto out; BUG_ON(err != len); err = 0; |
1da177e4c
|
2224 |
} |
89e107877
|
2225 2226 2227 2228 2229 2230 2231 2232 |
out: return err; } /* * For moronic filesystems that do not allow holes in file. * We may have to extend the file. */ |
282dc1788
|
2233 |
int cont_write_begin(struct file *file, struct address_space *mapping, |
89e107877
|
2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 |
loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata, get_block_t *get_block, loff_t *bytes) { struct inode *inode = mapping->host; unsigned blocksize = 1 << inode->i_blkbits; unsigned zerofrom; int err; err = cont_expand_zero(file, mapping, pos, bytes); if (err) |
155130a4f
|
2245 |
return err; |
89e107877
|
2246 2247 2248 2249 2250 |
zerofrom = *bytes & ~PAGE_CACHE_MASK; if (pos+len > *bytes && zerofrom & (blocksize-1)) { *bytes |= (blocksize-1); (*bytes)++; |
1da177e4c
|
2251 |
} |
1da177e4c
|
2252 |
|
155130a4f
|
2253 |
return block_write_begin(mapping, pos, len, flags, pagep, get_block); |
1da177e4c
|
2254 |
} |
1fe72eaa0
|
2255 |
EXPORT_SYMBOL(cont_write_begin); |
1da177e4c
|
2256 |
|
1da177e4c
|
2257 2258 2259 2260 2261 2262 |
int block_commit_write(struct page *page, unsigned from, unsigned to) { struct inode *inode = page->mapping->host; __block_commit_write(inode,page,from,to); return 0; } |
1fe72eaa0
|
2263 |
EXPORT_SYMBOL(block_commit_write); |
1da177e4c
|
2264 |
|
541716902
|
2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 |
/* * block_page_mkwrite() is not allowed to change the file size as it gets * called from a page fault handler when a page is first dirtied. Hence we must * be careful to check for EOF conditions here. We set the page up correctly * for a written page which means we get ENOSPC checking when writing into * holes and correct delalloc and unwritten extent mapping on filesystems that * support these features. * * We are not allowed to take the i_mutex here so we have to play games to * protect against truncate races as the page could now be beyond EOF. Because |
7bb46a673
|
2275 |
* truncate writes the inode size before removing pages, once we have the |
541716902
|
2276 2277 2278 |
* page lock we can determine safely if the page is beyond EOF. If it is not * beyond EOF, then the page is guaranteed safe against truncation until we * unlock the page. |
ea13a8646
|
2279 |
* |
14da92001
|
2280 2281 |
* Direct callers of this function should protect against filesystem freezing * using sb_start_write() - sb_end_write() functions. |
541716902
|
2282 |
*/ |
24da4fab5
|
2283 2284 |
int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, get_block_t get_block) |
541716902
|
2285 |
{ |
c2ec175c3
|
2286 |
struct page *page = vmf->page; |
541716902
|
2287 2288 2289 |
struct inode *inode = vma->vm_file->f_path.dentry->d_inode; unsigned long end; loff_t size; |
24da4fab5
|
2290 |
int ret; |
541716902
|
2291 |
|
5e8830dc8
|
2292 2293 2294 2295 2296 |
/* * Update file times before taking page lock. We may end up failing the * fault so this update may be superfluous but who really cares... */ file_update_time(vma->vm_file); |
541716902
|
2297 2298 2299 |
lock_page(page); size = i_size_read(inode); if ((page->mapping != inode->i_mapping) || |
183363380
|
2300 |
(page_offset(page) > size)) { |
24da4fab5
|
2301 2302 2303 |
/* We overload EFAULT to mean page got truncated */ ret = -EFAULT; goto out_unlock; |
541716902
|
2304 2305 2306 2307 2308 2309 2310 |
} /* page is wholly or partially inside EOF */ if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) end = size & ~PAGE_CACHE_MASK; else end = PAGE_CACHE_SIZE; |
ebdec241d
|
2311 |
ret = __block_write_begin(page, 0, end, get_block); |
541716902
|
2312 2313 |
if (!ret) ret = block_commit_write(page, 0, end); |
24da4fab5
|
2314 2315 |
if (unlikely(ret < 0)) goto out_unlock; |
ea13a8646
|
2316 |
set_page_dirty(page); |
d76ee18a8
|
2317 |
wait_on_page_writeback(page); |
24da4fab5
|
2318 2319 2320 |
return 0; out_unlock: unlock_page(page); |
541716902
|
2321 |
return ret; |
24da4fab5
|
2322 2323 2324 2325 2326 2327 |
} EXPORT_SYMBOL(__block_page_mkwrite); int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, get_block_t get_block) { |
ea13a8646
|
2328 2329 |
int ret; struct super_block *sb = vma->vm_file->f_path.dentry->d_inode->i_sb; |
24da4fab5
|
2330 |
|
14da92001
|
2331 |
sb_start_pagefault(sb); |
ea13a8646
|
2332 |
ret = __block_page_mkwrite(vma, vmf, get_block); |
14da92001
|
2333 |
sb_end_pagefault(sb); |
24da4fab5
|
2334 |
return block_page_mkwrite_return(ret); |
541716902
|
2335 |
} |
1fe72eaa0
|
2336 |
EXPORT_SYMBOL(block_page_mkwrite); |
1da177e4c
|
2337 2338 |
/* |
03158cd7e
|
2339 |
* nobh_write_begin()'s prereads are special: the buffer_heads are freed |
1da177e4c
|
2340 2341 |
* immediately, while under the page lock. So it needs a special end_io * handler which does not touch the bh after unlocking it. |
1da177e4c
|
2342 2343 2344 |
*/ static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) { |
68671f35f
|
2345 |
__end_buffer_read_notouch(bh, uptodate); |
1da177e4c
|
2346 2347 2348 |
} /* |
03158cd7e
|
2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 |
* Attach the singly-linked list of buffers created by nobh_write_begin, to * the page (converting it to circular linked list and taking care of page * dirty races). */ static void attach_nobh_buffers(struct page *page, struct buffer_head *head) { struct buffer_head *bh; BUG_ON(!PageLocked(page)); spin_lock(&page->mapping->private_lock); bh = head; do { if (PageDirty(page)) set_buffer_dirty(bh); if (!bh->b_this_page) bh->b_this_page = head; bh = bh->b_this_page; } while (bh != head); attach_page_buffers(page, head); spin_unlock(&page->mapping->private_lock); } /* |
ea0f04e59
|
2373 2374 |
* On entry, the page is fully not uptodate. * On exit the page is fully uptodate in the areas outside (from,to) |
7bb46a673
|
2375 |
* The filesystem needs to handle block truncation upon failure. |
1da177e4c
|
2376 |
*/ |
ea0f04e59
|
2377 |
int nobh_write_begin(struct address_space *mapping, |
03158cd7e
|
2378 2379 |
loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata, |
1da177e4c
|
2380 2381 |
get_block_t *get_block) { |
03158cd7e
|
2382 |
struct inode *inode = mapping->host; |
1da177e4c
|
2383 2384 |
const unsigned blkbits = inode->i_blkbits; const unsigned blocksize = 1 << blkbits; |
a4b0672db
|
2385 |
struct buffer_head *head, *bh; |
03158cd7e
|
2386 2387 2388 |
struct page *page; pgoff_t index; unsigned from, to; |
1da177e4c
|
2389 |
unsigned block_in_page; |
a4b0672db
|
2390 |
unsigned block_start, block_end; |
1da177e4c
|
2391 |
sector_t block_in_file; |
1da177e4c
|
2392 |
int nr_reads = 0; |
1da177e4c
|
2393 2394 |
int ret = 0; int is_mapped_to_disk = 1; |
1da177e4c
|
2395 |
|
03158cd7e
|
2396 2397 2398 |
index = pos >> PAGE_CACHE_SHIFT; from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; |
54566b2c1
|
2399 |
page = grab_cache_page_write_begin(mapping, index, flags); |
03158cd7e
|
2400 2401 2402 2403 2404 2405 |
if (!page) return -ENOMEM; *pagep = page; *fsdata = NULL; if (page_has_buffers(page)) { |
309f77ad9
|
2406 2407 2408 2409 |
ret = __block_write_begin(page, pos, len, get_block); if (unlikely(ret)) goto out_release; return ret; |
03158cd7e
|
2410 |
} |
a4b0672db
|
2411 |
|
1da177e4c
|
2412 2413 |
if (PageMappedToDisk(page)) return 0; |
a4b0672db
|
2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 |
/* * Allocate buffers so that we can keep track of state, and potentially * attach them to the page if an error occurs. In the common case of * no error, they will just be freed again without ever being attached * to the page (which is all OK, because we're under the page lock). * * Be careful: the buffer linked list is a NULL terminated one, rather * than the circular one we're used to. */ head = alloc_page_buffers(page, blocksize, 0); |
03158cd7e
|
2424 2425 2426 2427 |
if (!head) { ret = -ENOMEM; goto out_release; } |
a4b0672db
|
2428 |
|
1da177e4c
|
2429 |
block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits); |
1da177e4c
|
2430 2431 2432 2433 2434 2435 |
/* * We loop across all blocks in the page, whether or not they are * part of the affected region. This is so we can discover if the * page is fully mapped-to-disk. */ |
a4b0672db
|
2436 |
for (block_start = 0, block_in_page = 0, bh = head; |
1da177e4c
|
2437 |
block_start < PAGE_CACHE_SIZE; |
a4b0672db
|
2438 |
block_in_page++, block_start += blocksize, bh = bh->b_this_page) { |
1da177e4c
|
2439 |
int create; |
a4b0672db
|
2440 2441 |
block_end = block_start + blocksize; bh->b_state = 0; |
1da177e4c
|
2442 2443 2444 2445 |
create = 1; if (block_start >= to) create = 0; ret = get_block(inode, block_in_file + block_in_page, |
a4b0672db
|
2446 |
bh, create); |
1da177e4c
|
2447 2448 |
if (ret) goto failed; |
a4b0672db
|
2449 |
if (!buffer_mapped(bh)) |
1da177e4c
|
2450 |
is_mapped_to_disk = 0; |
a4b0672db
|
2451 2452 2453 2454 |
if (buffer_new(bh)) unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); if (PageUptodate(page)) { set_buffer_uptodate(bh); |
1da177e4c
|
2455 |
continue; |
a4b0672db
|
2456 2457 |
} if (buffer_new(bh) || !buffer_mapped(bh)) { |
eebd2aa35
|
2458 2459 |
zero_user_segments(page, block_start, from, to, block_end); |
1da177e4c
|
2460 2461 |
continue; } |
a4b0672db
|
2462 |
if (buffer_uptodate(bh)) |
1da177e4c
|
2463 2464 |
continue; /* reiserfs does this */ if (block_start < from || block_end > to) { |
a4b0672db
|
2465 2466 2467 2468 |
lock_buffer(bh); bh->b_end_io = end_buffer_read_nobh; submit_bh(READ, bh); nr_reads++; |
1da177e4c
|
2469 2470 2471 2472 |
} } if (nr_reads) { |
1da177e4c
|
2473 2474 2475 2476 2477 |
/* * The page is locked, so these buffers are protected from * any VM or truncate activity. Hence we don't need to care * for the buffer_head refcounts. */ |
a4b0672db
|
2478 |
for (bh = head; bh; bh = bh->b_this_page) { |
1da177e4c
|
2479 2480 2481 |
wait_on_buffer(bh); if (!buffer_uptodate(bh)) ret = -EIO; |
1da177e4c
|
2482 2483 2484 2485 2486 2487 2488 |
} if (ret) goto failed; } if (is_mapped_to_disk) SetPageMappedToDisk(page); |
1da177e4c
|
2489 |
|
03158cd7e
|
2490 |
*fsdata = head; /* to be released by nobh_write_end */ |
a4b0672db
|
2491 |
|
1da177e4c
|
2492 2493 2494 |
return 0; failed: |
03158cd7e
|
2495 |
BUG_ON(!ret); |
1da177e4c
|
2496 |
/* |
a4b0672db
|
2497 2498 2499 2500 2501 |
* Error recovery is a bit difficult. We need to zero out blocks that * were newly allocated, and dirty them to ensure they get written out. * Buffers need to be attached to the page at this point, otherwise * the handling of potential IO errors during writeout would be hard * (could try doing synchronous writeout, but what if that fails too?) |
1da177e4c
|
2502 |
*/ |
03158cd7e
|
2503 2504 |
attach_nobh_buffers(page, head); page_zero_new_buffers(page, from, to); |
a4b0672db
|
2505 |
|
03158cd7e
|
2506 2507 2508 2509 |
out_release: unlock_page(page); page_cache_release(page); *pagep = NULL; |
a4b0672db
|
2510 |
|
7bb46a673
|
2511 2512 |
return ret; } |
03158cd7e
|
2513 |
EXPORT_SYMBOL(nobh_write_begin); |
1da177e4c
|
2514 |
|
03158cd7e
|
2515 2516 2517 |
int nobh_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) |
1da177e4c
|
2518 2519 |
{ struct inode *inode = page->mapping->host; |
efdc31319
|
2520 |
struct buffer_head *head = fsdata; |
03158cd7e
|
2521 |
struct buffer_head *bh; |
5b41e74ad
|
2522 |
BUG_ON(fsdata != NULL && page_has_buffers(page)); |
1da177e4c
|
2523 |
|
d4cf109f0
|
2524 |
if (unlikely(copied < len) && head) |
5b41e74ad
|
2525 2526 2527 2528 |
attach_nobh_buffers(page, head); if (page_has_buffers(page)) return generic_write_end(file, mapping, pos, len, copied, page, fsdata); |
a4b0672db
|
2529 |
|
22c8ca78f
|
2530 |
SetPageUptodate(page); |
1da177e4c
|
2531 |
set_page_dirty(page); |
03158cd7e
|
2532 2533 |
if (pos+copied > inode->i_size) { i_size_write(inode, pos+copied); |
1da177e4c
|
2534 2535 |
mark_inode_dirty(inode); } |
03158cd7e
|
2536 2537 2538 |
unlock_page(page); page_cache_release(page); |
03158cd7e
|
2539 2540 2541 2542 2543 2544 2545 |
while (head) { bh = head; head = head->b_this_page; free_buffer_head(bh); } return copied; |
1da177e4c
|
2546 |
} |
03158cd7e
|
2547 |
EXPORT_SYMBOL(nobh_write_end); |
1da177e4c
|
2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 |
/* * nobh_writepage() - based on block_full_write_page() except * that it tries to operate without attaching bufferheads to * the page. */ int nobh_writepage(struct page *page, get_block_t *get_block, struct writeback_control *wbc) { struct inode * const inode = page->mapping->host; loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; unsigned offset; |
1da177e4c
|
2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 |
int ret; /* Is the page fully inside i_size? */ if (page->index < end_index) goto out; /* Is the page fully outside i_size? (truncate in progress) */ offset = i_size & (PAGE_CACHE_SIZE-1); if (page->index >= end_index+1 || !offset) { /* * The page may have dirty, unmapped buffers. For example, * they may have been added in ext3_writepage(). Make them * freeable here, so the page does not leak. */ #if 0 /* Not really sure about this - do we need this ? */ if (page->mapping->a_ops->invalidatepage) page->mapping->a_ops->invalidatepage(page, offset); #endif unlock_page(page); return 0; /* don't care */ } /* * The page straddles i_size. It must be zeroed out on each and every * writepage invocation because it may be mmapped. "A file is mapped * in multiples of the page size. For a file that is not a multiple of * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ |
eebd2aa35
|
2591 |
zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
1da177e4c
|
2592 2593 2594 |
out: ret = mpage_writepage(page, get_block, wbc); if (ret == -EAGAIN) |
35c80d5f4
|
2595 2596 |
ret = __block_write_full_page(inode, page, get_block, wbc, end_buffer_async_write); |
1da177e4c
|
2597 2598 2599 |
return ret; } EXPORT_SYMBOL(nobh_writepage); |
03158cd7e
|
2600 2601 |
int nobh_truncate_page(struct address_space *mapping, loff_t from, get_block_t *get_block) |
1da177e4c
|
2602 |
{ |
1da177e4c
|
2603 2604 |
pgoff_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); |
03158cd7e
|
2605 2606 2607 2608 |
unsigned blocksize; sector_t iblock; unsigned length, pos; struct inode *inode = mapping->host; |
1da177e4c
|
2609 |
struct page *page; |
03158cd7e
|
2610 2611 |
struct buffer_head map_bh; int err; |
1da177e4c
|
2612 |
|
03158cd7e
|
2613 2614 2615 2616 2617 2618 2619 2620 2621 |
blocksize = 1 << inode->i_blkbits; length = offset & (blocksize - 1); /* Block boundary? Nothing to do */ if (!length) return 0; length = blocksize - length; iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
1da177e4c
|
2622 |
|
1da177e4c
|
2623 |
page = grab_cache_page(mapping, index); |
03158cd7e
|
2624 |
err = -ENOMEM; |
1da177e4c
|
2625 2626 |
if (!page) goto out; |
03158cd7e
|
2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 |
if (page_has_buffers(page)) { has_buffers: unlock_page(page); page_cache_release(page); return block_truncate_page(mapping, from, get_block); } /* Find the buffer that contains "offset" */ pos = blocksize; while (offset >= pos) { iblock++; pos += blocksize; } |
460bcf57b
|
2640 2641 |
map_bh.b_size = blocksize; map_bh.b_state = 0; |
03158cd7e
|
2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 |
err = get_block(inode, iblock, &map_bh, 0); if (err) goto unlock; /* unmapped? It's a hole - nothing to do */ if (!buffer_mapped(&map_bh)) goto unlock; /* Ok, it's mapped. Make sure it's up-to-date */ if (!PageUptodate(page)) { err = mapping->a_ops->readpage(NULL, page); if (err) { page_cache_release(page); goto out; } lock_page(page); if (!PageUptodate(page)) { err = -EIO; goto unlock; } if (page_has_buffers(page)) goto has_buffers; |
1da177e4c
|
2663 |
} |
eebd2aa35
|
2664 |
zero_user(page, offset, length); |
03158cd7e
|
2665 2666 2667 2668 |
set_page_dirty(page); err = 0; unlock: |
1da177e4c
|
2669 2670 2671 |
unlock_page(page); page_cache_release(page); out: |
03158cd7e
|
2672 |
return err; |
1da177e4c
|
2673 2674 2675 2676 2677 2678 2679 2680 2681 |
} EXPORT_SYMBOL(nobh_truncate_page); int block_truncate_page(struct address_space *mapping, loff_t from, get_block_t *get_block) { pgoff_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); unsigned blocksize; |
54b21a799
|
2682 |
sector_t iblock; |
1da177e4c
|
2683 2684 2685 2686 |
unsigned length, pos; struct inode *inode = mapping->host; struct page *page; struct buffer_head *bh; |
1da177e4c
|
2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 |
int err; blocksize = 1 << inode->i_blkbits; length = offset & (blocksize - 1); /* Block boundary? Nothing to do */ if (!length) return 0; length = blocksize - length; |
54b21a799
|
2697 |
iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
1da177e4c
|
2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 |
page = grab_cache_page(mapping, index); err = -ENOMEM; if (!page) goto out; if (!page_has_buffers(page)) create_empty_buffers(page, blocksize, 0); /* Find the buffer that contains "offset" */ bh = page_buffers(page); pos = blocksize; while (offset >= pos) { bh = bh->b_this_page; iblock++; pos += blocksize; } err = 0; if (!buffer_mapped(bh)) { |
b0cf2321c
|
2718 |
WARN_ON(bh->b_size != blocksize); |
1da177e4c
|
2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 |
err = get_block(inode, iblock, bh, 0); if (err) goto unlock; /* unmapped? It's a hole - nothing to do */ if (!buffer_mapped(bh)) goto unlock; } /* Ok, it's mapped. Make sure it's up-to-date */ if (PageUptodate(page)) set_buffer_uptodate(bh); |
33a266dda
|
2730 |
if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) { |
1da177e4c
|
2731 2732 2733 2734 2735 2736 2737 |
err = -EIO; ll_rw_block(READ, 1, &bh); wait_on_buffer(bh); /* Uhhuh. Read error. Complain and punt. */ if (!buffer_uptodate(bh)) goto unlock; } |
eebd2aa35
|
2738 |
zero_user(page, offset, length); |
1da177e4c
|
2739 2740 2741 2742 2743 2744 2745 2746 2747 |
mark_buffer_dirty(bh); err = 0; unlock: unlock_page(page); page_cache_release(page); out: return err; } |
1fe72eaa0
|
2748 |
EXPORT_SYMBOL(block_truncate_page); |
1da177e4c
|
2749 2750 2751 |
/* * The generic ->writepage function for buffer-backed address_spaces |
35c80d5f4
|
2752 |
* this form passes in the end_io handler used to finish the IO. |
1da177e4c
|
2753 |
*/ |
35c80d5f4
|
2754 2755 |
int block_write_full_page_endio(struct page *page, get_block_t *get_block, struct writeback_control *wbc, bh_end_io_t *handler) |
1da177e4c
|
2756 2757 2758 2759 2760 |
{ struct inode * const inode = page->mapping->host; loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; unsigned offset; |
1da177e4c
|
2761 2762 2763 |
/* Is the page fully inside i_size? */ if (page->index < end_index) |
35c80d5f4
|
2764 2765 |
return __block_write_full_page(inode, page, get_block, wbc, handler); |
1da177e4c
|
2766 2767 2768 2769 2770 2771 2772 2773 2774 |
/* Is the page fully outside i_size? (truncate in progress) */ offset = i_size & (PAGE_CACHE_SIZE-1); if (page->index >= end_index+1 || !offset) { /* * The page may have dirty, unmapped buffers. For example, * they may have been added in ext3_writepage(). Make them * freeable here, so the page does not leak. */ |
aaa4059bc
|
2775 |
do_invalidatepage(page, 0); |
1da177e4c
|
2776 2777 2778 2779 2780 2781 |
unlock_page(page); return 0; /* don't care */ } /* * The page straddles i_size. It must be zeroed out on each and every |
2a61aa401
|
2782 |
* writepage invocation because it may be mmapped. "A file is mapped |
1da177e4c
|
2783 2784 2785 2786 |
* in multiples of the page size. For a file that is not a multiple of * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ |
eebd2aa35
|
2787 |
zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
35c80d5f4
|
2788 |
return __block_write_full_page(inode, page, get_block, wbc, handler); |
1da177e4c
|
2789 |
} |
1fe72eaa0
|
2790 |
EXPORT_SYMBOL(block_write_full_page_endio); |
1da177e4c
|
2791 |
|
35c80d5f4
|
2792 2793 2794 2795 2796 2797 2798 2799 2800 |
/* * The generic ->writepage function for buffer-backed address_spaces */ int block_write_full_page(struct page *page, get_block_t *get_block, struct writeback_control *wbc) { return block_write_full_page_endio(page, get_block, wbc, end_buffer_async_write); } |
1fe72eaa0
|
2801 |
EXPORT_SYMBOL(block_write_full_page); |
35c80d5f4
|
2802 |
|
1da177e4c
|
2803 2804 2805 2806 2807 2808 2809 |
sector_t generic_block_bmap(struct address_space *mapping, sector_t block, get_block_t *get_block) { struct buffer_head tmp; struct inode *inode = mapping->host; tmp.b_state = 0; tmp.b_blocknr = 0; |
b0cf2321c
|
2810 |
tmp.b_size = 1 << inode->i_blkbits; |
1da177e4c
|
2811 2812 2813 |
get_block(inode, block, &tmp, 0); return tmp.b_blocknr; } |
1fe72eaa0
|
2814 |
EXPORT_SYMBOL(generic_block_bmap); |
1da177e4c
|
2815 |
|
6712ecf8f
|
2816 |
static void end_bio_bh_io_sync(struct bio *bio, int err) |
1da177e4c
|
2817 2818 |
{ struct buffer_head *bh = bio->bi_private; |
1da177e4c
|
2819 2820 |
if (err == -EOPNOTSUPP) { set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); |
1da177e4c
|
2821 |
} |
08bafc034
|
2822 2823 |
if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags))) set_bit(BH_Quiet, &bh->b_state); |
1da177e4c
|
2824 2825 |
bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); bio_put(bio); |
1da177e4c
|
2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 |
} int submit_bh(int rw, struct buffer_head * bh) { struct bio *bio; int ret = 0; BUG_ON(!buffer_locked(bh)); BUG_ON(!buffer_mapped(bh)); BUG_ON(!bh->b_end_io); |
8fb0e3424
|
2836 2837 |
BUG_ON(buffer_delay(bh)); BUG_ON(buffer_unwritten(bh)); |
1da177e4c
|
2838 |
|
48fd4f93a
|
2839 |
/* |
48fd4f93a
|
2840 |
* Only clear out a write error when rewriting |
1da177e4c
|
2841 |
*/ |
48fd4f93a
|
2842 |
if (test_set_buffer_req(bh) && (rw & WRITE)) |
1da177e4c
|
2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 |
clear_buffer_write_io_error(bh); /* * from here on down, it's all bio -- do the initial mapping, * submit_bio -> generic_make_request may further map this bio around */ bio = bio_alloc(GFP_NOIO, 1); bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); bio->bi_bdev = bh->b_bdev; bio->bi_io_vec[0].bv_page = bh->b_page; bio->bi_io_vec[0].bv_len = bh->b_size; bio->bi_io_vec[0].bv_offset = bh_offset(bh); bio->bi_vcnt = 1; bio->bi_idx = 0; bio->bi_size = bh->b_size; bio->bi_end_io = end_bio_bh_io_sync; bio->bi_private = bh; bio_get(bio); submit_bio(rw, bio); if (bio_flagged(bio, BIO_EOPNOTSUPP)) ret = -EOPNOTSUPP; bio_put(bio); return ret; } |
1fe72eaa0
|
2873 |
EXPORT_SYMBOL(submit_bh); |
1da177e4c
|
2874 2875 2876 |
/** * ll_rw_block: low-level access to block devices (DEPRECATED) |
9cb569d60
|
2877 |
* @rw: whether to %READ or %WRITE or maybe %READA (readahead) |
1da177e4c
|
2878 2879 2880 |
* @nr: number of &struct buffer_heads in the array * @bhs: array of pointers to &struct buffer_head * |
a76622362
|
2881 2882 |
* ll_rw_block() takes an array of pointers to &struct buffer_heads, and * requests an I/O operation on them, either a %READ or a %WRITE. The third |
9cb569d60
|
2883 2884 |
* %READA option is described in the documentation for generic_make_request() * which ll_rw_block() calls. |
1da177e4c
|
2885 2886 |
* * This function drops any buffer that it cannot get a lock on (with the |
9cb569d60
|
2887 2888 2889 2890 2891 |
* BH_Lock state bit), any buffer that appears to be clean when doing a write * request, and any buffer that appears to be up-to-date when doing read * request. Further it marks as clean buffers that are processed for * writing (the buffer cache won't assume that they are actually clean * until the buffer gets unlocked). |
1da177e4c
|
2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 |
* * ll_rw_block sets b_end_io to simple completion handler that marks * the buffer up-to-date (if approriate), unlocks the buffer and wakes * any waiters. * * All of the buffers must be for the same device, and must also be a * multiple of the current approved size for the device. */ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[]) { int i; for (i = 0; i < nr; i++) { struct buffer_head *bh = bhs[i]; |
9cb569d60
|
2906 |
if (!trylock_buffer(bh)) |
1da177e4c
|
2907 |
continue; |
9cb569d60
|
2908 |
if (rw == WRITE) { |
1da177e4c
|
2909 |
if (test_clear_buffer_dirty(bh)) { |
76c3073a8
|
2910 |
bh->b_end_io = end_buffer_write_sync; |
e60e5c50a
|
2911 |
get_bh(bh); |
9cb569d60
|
2912 |
submit_bh(WRITE, bh); |
1da177e4c
|
2913 2914 2915 |
continue; } } else { |
1da177e4c
|
2916 |
if (!buffer_uptodate(bh)) { |
76c3073a8
|
2917 |
bh->b_end_io = end_buffer_read_sync; |
e60e5c50a
|
2918 |
get_bh(bh); |
1da177e4c
|
2919 2920 2921 2922 2923 |
submit_bh(rw, bh); continue; } } unlock_buffer(bh); |
1da177e4c
|
2924 2925 |
} } |
1fe72eaa0
|
2926 |
EXPORT_SYMBOL(ll_rw_block); |
1da177e4c
|
2927 |
|
9cb569d60
|
2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 |
void write_dirty_buffer(struct buffer_head *bh, int rw) { lock_buffer(bh); if (!test_clear_buffer_dirty(bh)) { unlock_buffer(bh); return; } bh->b_end_io = end_buffer_write_sync; get_bh(bh); submit_bh(rw, bh); } EXPORT_SYMBOL(write_dirty_buffer); |
1da177e4c
|
2940 2941 2942 2943 2944 |
/* * For a data-integrity writeout, we need to wait upon any in-progress I/O * and then start new I/O and then wait upon it. The caller must have a ref on * the buffer_head. */ |
87e99511e
|
2945 |
int __sync_dirty_buffer(struct buffer_head *bh, int rw) |
1da177e4c
|
2946 2947 2948 2949 2950 2951 2952 2953 |
{ int ret = 0; WARN_ON(atomic_read(&bh->b_count) < 1); lock_buffer(bh); if (test_clear_buffer_dirty(bh)) { get_bh(bh); bh->b_end_io = end_buffer_write_sync; |
87e99511e
|
2954 |
ret = submit_bh(rw, bh); |
1da177e4c
|
2955 |
wait_on_buffer(bh); |
1da177e4c
|
2956 2957 2958 2959 2960 2961 2962 |
if (!ret && !buffer_uptodate(bh)) ret = -EIO; } else { unlock_buffer(bh); } return ret; } |
87e99511e
|
2963 2964 2965 2966 2967 2968 |
EXPORT_SYMBOL(__sync_dirty_buffer); int sync_dirty_buffer(struct buffer_head *bh) { return __sync_dirty_buffer(bh, WRITE_SYNC); } |
1fe72eaa0
|
2969 |
EXPORT_SYMBOL(sync_dirty_buffer); |
1da177e4c
|
2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 |
/* * try_to_free_buffers() checks if all the buffers on this particular page * are unused, and releases them if so. * * Exclusion against try_to_free_buffers may be obtained by either * locking the page or by holding its mapping's private_lock. * * If the page is dirty but all the buffers are clean then we need to * be sure to mark the page clean as well. This is because the page * may be against a block device, and a later reattachment of buffers * to a dirty page will set *all* buffers dirty. Which would corrupt * filesystem data on the same device. * * The same applies to regular filesystem pages: if all the buffers are * clean then we set the page clean and proceed. To do that, we require * total exclusion from __set_page_dirty_buffers(). That is obtained with * private_lock. * * try_to_free_buffers() is non-blocking. */ static inline int buffer_busy(struct buffer_head *bh) { return atomic_read(&bh->b_count) | (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock))); } static int drop_buffers(struct page *page, struct buffer_head **buffers_to_free) { struct buffer_head *head = page_buffers(page); struct buffer_head *bh; bh = head; do { |
de7d5a3b6
|
3005 |
if (buffer_write_io_error(bh) && page->mapping) |
1da177e4c
|
3006 3007 3008 3009 3010 3011 3012 3013 |
set_bit(AS_EIO, &page->mapping->flags); if (buffer_busy(bh)) goto failed; bh = bh->b_this_page; } while (bh != head); do { struct buffer_head *next = bh->b_this_page; |
535ee2fbf
|
3014 |
if (bh->b_assoc_map) |
1da177e4c
|
3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 |
__remove_assoc_queue(bh); bh = next; } while (bh != head); *buffers_to_free = head; __clear_page_buffers(page); return 1; failed: return 0; } int try_to_free_buffers(struct page *page) { struct address_space * const mapping = page->mapping; struct buffer_head *buffers_to_free = NULL; int ret = 0; BUG_ON(!PageLocked(page)); |
ecdfc9787
|
3032 |
if (PageWriteback(page)) |
1da177e4c
|
3033 3034 3035 3036 3037 3038 3039 3040 3041 |
return 0; if (mapping == NULL) { /* can this still happen? */ ret = drop_buffers(page, &buffers_to_free); goto out; } spin_lock(&mapping->private_lock); ret = drop_buffers(page, &buffers_to_free); |
ecdfc9787
|
3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 |
/* * If the filesystem writes its buffers by hand (eg ext3) * then we can have clean buffers against a dirty page. We * clean the page here; otherwise the VM will never notice * that the filesystem did any IO at all. * * Also, during truncate, discard_buffer will have marked all * the page's buffers clean. We discover that here and clean * the page also. |
87df7241b
|
3052 3053 3054 3055 |
* * private_lock must be held over this entire operation in order * to synchronise against __set_page_dirty_buffers and prevent the * dirty bit from being lost. |
ecdfc9787
|
3056 3057 3058 |
*/ if (ret) cancel_dirty_page(page, PAGE_CACHE_SIZE); |
87df7241b
|
3059 |
spin_unlock(&mapping->private_lock); |
1da177e4c
|
3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 |
out: if (buffers_to_free) { struct buffer_head *bh = buffers_to_free; do { struct buffer_head *next = bh->b_this_page; free_buffer_head(bh); bh = next; } while (bh != buffers_to_free); } return ret; } EXPORT_SYMBOL(try_to_free_buffers); |
1da177e4c
|
3073 3074 3075 3076 3077 |
/* * There are no bdflush tunables left. But distributions are * still running obsolete flush daemons, so we terminate them here. * * Use of bdflush() is deprecated and will be removed in a future kernel. |
5b0830cb9
|
3078 |
* The `flush-X' kernel threads fully replace bdflush daemons and this call. |
1da177e4c
|
3079 |
*/ |
bdc480e3b
|
3080 |
SYSCALL_DEFINE2(bdflush, int, func, long, data) |
1da177e4c
|
3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 |
{ static int msg_count; if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (msg_count < 5) { msg_count++; printk(KERN_INFO "warning: process `%s' used the obsolete bdflush" " system call ", current->comm); printk(KERN_INFO "Fix your initscripts? "); } if (func == 1) do_exit(0); return 0; } /* * Buffer-head allocation */ |
a0a9b0433
|
3105 |
static struct kmem_cache *bh_cachep __read_mostly; |
1da177e4c
|
3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 |
/* * Once the number of bh's in the machine exceeds this level, we start * stripping them in writeback. */ static int max_buffer_heads; int buffer_heads_over_limit; struct bh_accounting { int nr; /* Number of live bh's */ int ratelimit; /* Limit cacheline bouncing */ }; static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0}; static void recalc_bh_state(void) { int i; int tot = 0; |
ee1be8626
|
3126 |
if (__this_cpu_inc_return(bh_accounting.ratelimit) - 1 < 4096) |
1da177e4c
|
3127 |
return; |
c7b92516a
|
3128 |
__this_cpu_write(bh_accounting.ratelimit, 0); |
8a1434268
|
3129 |
for_each_online_cpu(i) |
1da177e4c
|
3130 3131 3132 |
tot += per_cpu(bh_accounting, i).nr; buffer_heads_over_limit = (tot > max_buffer_heads); } |
c7b92516a
|
3133 |
|
dd0fc66fb
|
3134 |
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) |
1da177e4c
|
3135 |
{ |
019b4d123
|
3136 |
struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags); |
1da177e4c
|
3137 |
if (ret) { |
a35afb830
|
3138 |
INIT_LIST_HEAD(&ret->b_assoc_buffers); |
c7b92516a
|
3139 3140 |
preempt_disable(); __this_cpu_inc(bh_accounting.nr); |
1da177e4c
|
3141 |
recalc_bh_state(); |
c7b92516a
|
3142 |
preempt_enable(); |
1da177e4c
|
3143 3144 3145 3146 3147 3148 3149 3150 3151 |
} return ret; } EXPORT_SYMBOL(alloc_buffer_head); void free_buffer_head(struct buffer_head *bh) { BUG_ON(!list_empty(&bh->b_assoc_buffers)); kmem_cache_free(bh_cachep, bh); |
c7b92516a
|
3152 3153 |
preempt_disable(); __this_cpu_dec(bh_accounting.nr); |
1da177e4c
|
3154 |
recalc_bh_state(); |
c7b92516a
|
3155 |
preempt_enable(); |
1da177e4c
|
3156 3157 |
} EXPORT_SYMBOL(free_buffer_head); |
1da177e4c
|
3158 3159 3160 3161 3162 3163 3164 3165 3166 |
static void buffer_exit_cpu(int cpu) { int i; struct bh_lru *b = &per_cpu(bh_lrus, cpu); for (i = 0; i < BH_LRU_SIZE; i++) { brelse(b->bhs[i]); b->bhs[i] = NULL; } |
c7b92516a
|
3167 |
this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr); |
8a1434268
|
3168 |
per_cpu(bh_accounting, cpu).nr = 0; |
1da177e4c
|
3169 3170 3171 3172 3173 |
} static int buffer_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { |
8bb784428
|
3174 |
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) |
1da177e4c
|
3175 3176 3177 |
buffer_exit_cpu((unsigned long)hcpu); return NOTIFY_OK; } |
1da177e4c
|
3178 |
|
389d1b083
|
3179 |
/** |
a6b91919e
|
3180 |
* bh_uptodate_or_lock - Test whether the buffer is uptodate |
389d1b083
|
3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 |
* @bh: struct buffer_head * * Return true if the buffer is up-to-date and false, * with the buffer locked, if not. */ int bh_uptodate_or_lock(struct buffer_head *bh) { if (!buffer_uptodate(bh)) { lock_buffer(bh); if (!buffer_uptodate(bh)) return 0; unlock_buffer(bh); } return 1; } EXPORT_SYMBOL(bh_uptodate_or_lock); /** |
a6b91919e
|
3199 |
* bh_submit_read - Submit a locked buffer for reading |
389d1b083
|
3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 |
* @bh: struct buffer_head * * Returns zero on success and -EIO on error. */ int bh_submit_read(struct buffer_head *bh) { BUG_ON(!buffer_locked(bh)); if (buffer_uptodate(bh)) { unlock_buffer(bh); return 0; } get_bh(bh); bh->b_end_io = end_buffer_read_sync; submit_bh(READ, bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return 0; return -EIO; } EXPORT_SYMBOL(bh_submit_read); |
1da177e4c
|
3222 3223 3224 |
void __init buffer_init(void) { int nrpages; |
b98938c37
|
3225 3226 3227 3228 |
bh_cachep = kmem_cache_create("buffer_head", sizeof(struct buffer_head), 0, (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| SLAB_MEM_SPREAD), |
019b4d123
|
3229 |
NULL); |
1da177e4c
|
3230 3231 3232 3233 3234 3235 3236 3237 |
/* * Limit the bh occupancy to 10% of ZONE_NORMAL */ nrpages = (nr_free_buffer_pages() * 10) / 100; max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); hotcpu_notifier(buffer_cpu_notify, 0); } |