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1da177e4 LT |
1 | /* |
2 | * Copyright (c) 2000-2004 Silicon Graphics, Inc. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of version 2 of the GNU General Public License as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it would be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
11 | * | |
12 | * Further, this software is distributed without any warranty that it is | |
13 | * free of the rightful claim of any third person regarding infringement | |
14 | * or the like. Any license provided herein, whether implied or | |
15 | * otherwise, applies only to this software file. Patent licenses, if | |
16 | * any, provided herein do not apply to combinations of this program with | |
17 | * other software, or any other product whatsoever. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License along | |
20 | * with this program; if not, write the Free Software Foundation, Inc., 59 | |
21 | * Temple Place - Suite 330, Boston MA 02111-1307, USA. | |
22 | * | |
23 | * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, | |
24 | * Mountain View, CA 94043, or: | |
25 | * | |
26 | * http://www.sgi.com | |
27 | * | |
28 | * For further information regarding this notice, see: | |
29 | * | |
30 | * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ | |
31 | */ | |
32 | ||
33 | /* | |
34 | * The xfs_buf.c code provides an abstract buffer cache model on top | |
35 | * of the Linux page cache. Cached metadata blocks for a file system | |
36 | * are hashed to the inode for the block device. xfs_buf.c assembles | |
37 | * buffers (xfs_buf_t) on demand to aggregate such cached pages for I/O. | |
38 | * | |
39 | * Written by Steve Lord, Jim Mostek, Russell Cattelan | |
40 | * and Rajagopal Ananthanarayanan ("ananth") at SGI. | |
41 | * | |
42 | */ | |
43 | ||
44 | #include <linux/stddef.h> | |
45 | #include <linux/errno.h> | |
46 | #include <linux/slab.h> | |
47 | #include <linux/pagemap.h> | |
48 | #include <linux/init.h> | |
49 | #include <linux/vmalloc.h> | |
50 | #include <linux/bio.h> | |
51 | #include <linux/sysctl.h> | |
52 | #include <linux/proc_fs.h> | |
53 | #include <linux/workqueue.h> | |
54 | #include <linux/percpu.h> | |
55 | #include <linux/blkdev.h> | |
56 | #include <linux/hash.h> | |
57 | ||
58 | #include "xfs_linux.h" | |
59 | ||
60 | /* | |
61 | * File wide globals | |
62 | */ | |
63 | ||
64 | STATIC kmem_cache_t *pagebuf_cache; | |
65 | STATIC kmem_shaker_t pagebuf_shake; | |
66 | STATIC int pagebuf_daemon_wakeup(int, unsigned int); | |
67 | STATIC void pagebuf_delwri_queue(xfs_buf_t *, int); | |
68 | STATIC struct workqueue_struct *pagebuf_logio_workqueue; | |
69 | STATIC struct workqueue_struct *pagebuf_dataio_workqueue; | |
70 | ||
71 | /* | |
72 | * Pagebuf debugging | |
73 | */ | |
74 | ||
75 | #ifdef PAGEBUF_TRACE | |
76 | void | |
77 | pagebuf_trace( | |
78 | xfs_buf_t *pb, | |
79 | char *id, | |
80 | void *data, | |
81 | void *ra) | |
82 | { | |
83 | ktrace_enter(pagebuf_trace_buf, | |
84 | pb, id, | |
85 | (void *)(unsigned long)pb->pb_flags, | |
86 | (void *)(unsigned long)pb->pb_hold.counter, | |
87 | (void *)(unsigned long)pb->pb_sema.count.counter, | |
88 | (void *)current, | |
89 | data, ra, | |
90 | (void *)(unsigned long)((pb->pb_file_offset>>32) & 0xffffffff), | |
91 | (void *)(unsigned long)(pb->pb_file_offset & 0xffffffff), | |
92 | (void *)(unsigned long)pb->pb_buffer_length, | |
93 | NULL, NULL, NULL, NULL, NULL); | |
94 | } | |
95 | ktrace_t *pagebuf_trace_buf; | |
96 | #define PAGEBUF_TRACE_SIZE 4096 | |
97 | #define PB_TRACE(pb, id, data) \ | |
98 | pagebuf_trace(pb, id, (void *)data, (void *)__builtin_return_address(0)) | |
99 | #else | |
100 | #define PB_TRACE(pb, id, data) do { } while (0) | |
101 | #endif | |
102 | ||
103 | #ifdef PAGEBUF_LOCK_TRACKING | |
104 | # define PB_SET_OWNER(pb) ((pb)->pb_last_holder = current->pid) | |
105 | # define PB_CLEAR_OWNER(pb) ((pb)->pb_last_holder = -1) | |
106 | # define PB_GET_OWNER(pb) ((pb)->pb_last_holder) | |
107 | #else | |
108 | # define PB_SET_OWNER(pb) do { } while (0) | |
109 | # define PB_CLEAR_OWNER(pb) do { } while (0) | |
110 | # define PB_GET_OWNER(pb) do { } while (0) | |
111 | #endif | |
112 | ||
113 | /* | |
114 | * Pagebuf allocation / freeing. | |
115 | */ | |
116 | ||
117 | #define pb_to_gfp(flags) \ | |
118 | ((((flags) & PBF_READ_AHEAD) ? __GFP_NORETRY : \ | |
119 | ((flags) & PBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN) | |
120 | ||
121 | #define pb_to_km(flags) \ | |
122 | (((flags) & PBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP) | |
123 | ||
124 | ||
125 | #define pagebuf_allocate(flags) \ | |
126 | kmem_zone_alloc(pagebuf_cache, pb_to_km(flags)) | |
127 | #define pagebuf_deallocate(pb) \ | |
128 | kmem_zone_free(pagebuf_cache, (pb)); | |
129 | ||
130 | /* | |
131 | * Page Region interfaces. | |
132 | * | |
133 | * For pages in filesystems where the blocksize is smaller than the | |
134 | * pagesize, we use the page->private field (long) to hold a bitmap | |
135 | * of uptodate regions within the page. | |
136 | * | |
137 | * Each such region is "bytes per page / bits per long" bytes long. | |
138 | * | |
139 | * NBPPR == number-of-bytes-per-page-region | |
140 | * BTOPR == bytes-to-page-region (rounded up) | |
141 | * BTOPRT == bytes-to-page-region-truncated (rounded down) | |
142 | */ | |
143 | #if (BITS_PER_LONG == 32) | |
144 | #define PRSHIFT (PAGE_CACHE_SHIFT - 5) /* (32 == 1<<5) */ | |
145 | #elif (BITS_PER_LONG == 64) | |
146 | #define PRSHIFT (PAGE_CACHE_SHIFT - 6) /* (64 == 1<<6) */ | |
147 | #else | |
148 | #error BITS_PER_LONG must be 32 or 64 | |
149 | #endif | |
150 | #define NBPPR (PAGE_CACHE_SIZE/BITS_PER_LONG) | |
151 | #define BTOPR(b) (((unsigned int)(b) + (NBPPR - 1)) >> PRSHIFT) | |
152 | #define BTOPRT(b) (((unsigned int)(b) >> PRSHIFT)) | |
153 | ||
154 | STATIC unsigned long | |
155 | page_region_mask( | |
156 | size_t offset, | |
157 | size_t length) | |
158 | { | |
159 | unsigned long mask; | |
160 | int first, final; | |
161 | ||
162 | first = BTOPR(offset); | |
163 | final = BTOPRT(offset + length - 1); | |
164 | first = min(first, final); | |
165 | ||
166 | mask = ~0UL; | |
167 | mask <<= BITS_PER_LONG - (final - first); | |
168 | mask >>= BITS_PER_LONG - (final); | |
169 | ||
170 | ASSERT(offset + length <= PAGE_CACHE_SIZE); | |
171 | ASSERT((final - first) < BITS_PER_LONG && (final - first) >= 0); | |
172 | ||
173 | return mask; | |
174 | } | |
175 | ||
176 | STATIC inline void | |
177 | set_page_region( | |
178 | struct page *page, | |
179 | size_t offset, | |
180 | size_t length) | |
181 | { | |
182 | page->private |= page_region_mask(offset, length); | |
183 | if (page->private == ~0UL) | |
184 | SetPageUptodate(page); | |
185 | } | |
186 | ||
187 | STATIC inline int | |
188 | test_page_region( | |
189 | struct page *page, | |
190 | size_t offset, | |
191 | size_t length) | |
192 | { | |
193 | unsigned long mask = page_region_mask(offset, length); | |
194 | ||
195 | return (mask && (page->private & mask) == mask); | |
196 | } | |
197 | ||
198 | /* | |
199 | * Mapping of multi-page buffers into contiguous virtual space | |
200 | */ | |
201 | ||
202 | typedef struct a_list { | |
203 | void *vm_addr; | |
204 | struct a_list *next; | |
205 | } a_list_t; | |
206 | ||
207 | STATIC a_list_t *as_free_head; | |
208 | STATIC int as_list_len; | |
209 | STATIC DEFINE_SPINLOCK(as_lock); | |
210 | ||
211 | /* | |
212 | * Try to batch vunmaps because they are costly. | |
213 | */ | |
214 | STATIC void | |
215 | free_address( | |
216 | void *addr) | |
217 | { | |
218 | a_list_t *aentry; | |
219 | ||
220 | aentry = kmalloc(sizeof(a_list_t), GFP_ATOMIC & ~__GFP_HIGH); | |
221 | if (likely(aentry)) { | |
222 | spin_lock(&as_lock); | |
223 | aentry->next = as_free_head; | |
224 | aentry->vm_addr = addr; | |
225 | as_free_head = aentry; | |
226 | as_list_len++; | |
227 | spin_unlock(&as_lock); | |
228 | } else { | |
229 | vunmap(addr); | |
230 | } | |
231 | } | |
232 | ||
233 | STATIC void | |
234 | purge_addresses(void) | |
235 | { | |
236 | a_list_t *aentry, *old; | |
237 | ||
238 | if (as_free_head == NULL) | |
239 | return; | |
240 | ||
241 | spin_lock(&as_lock); | |
242 | aentry = as_free_head; | |
243 | as_free_head = NULL; | |
244 | as_list_len = 0; | |
245 | spin_unlock(&as_lock); | |
246 | ||
247 | while ((old = aentry) != NULL) { | |
248 | vunmap(aentry->vm_addr); | |
249 | aentry = aentry->next; | |
250 | kfree(old); | |
251 | } | |
252 | } | |
253 | ||
254 | /* | |
255 | * Internal pagebuf object manipulation | |
256 | */ | |
257 | ||
258 | STATIC void | |
259 | _pagebuf_initialize( | |
260 | xfs_buf_t *pb, | |
261 | xfs_buftarg_t *target, | |
262 | loff_t range_base, | |
263 | size_t range_length, | |
264 | page_buf_flags_t flags) | |
265 | { | |
266 | /* | |
267 | * We don't want certain flags to appear in pb->pb_flags. | |
268 | */ | |
269 | flags &= ~(PBF_LOCK|PBF_MAPPED|PBF_DONT_BLOCK|PBF_READ_AHEAD); | |
270 | ||
271 | memset(pb, 0, sizeof(xfs_buf_t)); | |
272 | atomic_set(&pb->pb_hold, 1); | |
273 | init_MUTEX_LOCKED(&pb->pb_iodonesema); | |
274 | INIT_LIST_HEAD(&pb->pb_list); | |
275 | INIT_LIST_HEAD(&pb->pb_hash_list); | |
276 | init_MUTEX_LOCKED(&pb->pb_sema); /* held, no waiters */ | |
277 | PB_SET_OWNER(pb); | |
278 | pb->pb_target = target; | |
279 | pb->pb_file_offset = range_base; | |
280 | /* | |
281 | * Set buffer_length and count_desired to the same value initially. | |
282 | * I/O routines should use count_desired, which will be the same in | |
283 | * most cases but may be reset (e.g. XFS recovery). | |
284 | */ | |
285 | pb->pb_buffer_length = pb->pb_count_desired = range_length; | |
286 | pb->pb_flags = flags | PBF_NONE; | |
287 | pb->pb_bn = XFS_BUF_DADDR_NULL; | |
288 | atomic_set(&pb->pb_pin_count, 0); | |
289 | init_waitqueue_head(&pb->pb_waiters); | |
290 | ||
291 | XFS_STATS_INC(pb_create); | |
292 | PB_TRACE(pb, "initialize", target); | |
293 | } | |
294 | ||
295 | /* | |
296 | * Allocate a page array capable of holding a specified number | |
297 | * of pages, and point the page buf at it. | |
298 | */ | |
299 | STATIC int | |
300 | _pagebuf_get_pages( | |
301 | xfs_buf_t *pb, | |
302 | int page_count, | |
303 | page_buf_flags_t flags) | |
304 | { | |
305 | /* Make sure that we have a page list */ | |
306 | if (pb->pb_pages == NULL) { | |
307 | pb->pb_offset = page_buf_poff(pb->pb_file_offset); | |
308 | pb->pb_page_count = page_count; | |
309 | if (page_count <= PB_PAGES) { | |
310 | pb->pb_pages = pb->pb_page_array; | |
311 | } else { | |
312 | pb->pb_pages = kmem_alloc(sizeof(struct page *) * | |
313 | page_count, pb_to_km(flags)); | |
314 | if (pb->pb_pages == NULL) | |
315 | return -ENOMEM; | |
316 | } | |
317 | memset(pb->pb_pages, 0, sizeof(struct page *) * page_count); | |
318 | } | |
319 | return 0; | |
320 | } | |
321 | ||
322 | /* | |
323 | * Frees pb_pages if it was malloced. | |
324 | */ | |
325 | STATIC void | |
326 | _pagebuf_free_pages( | |
327 | xfs_buf_t *bp) | |
328 | { | |
329 | if (bp->pb_pages != bp->pb_page_array) { | |
330 | kmem_free(bp->pb_pages, | |
331 | bp->pb_page_count * sizeof(struct page *)); | |
332 | } | |
333 | } | |
334 | ||
335 | /* | |
336 | * Releases the specified buffer. | |
337 | * | |
338 | * The modification state of any associated pages is left unchanged. | |
339 | * The buffer most not be on any hash - use pagebuf_rele instead for | |
340 | * hashed and refcounted buffers | |
341 | */ | |
342 | void | |
343 | pagebuf_free( | |
344 | xfs_buf_t *bp) | |
345 | { | |
346 | PB_TRACE(bp, "free", 0); | |
347 | ||
348 | ASSERT(list_empty(&bp->pb_hash_list)); | |
349 | ||
350 | if (bp->pb_flags & _PBF_PAGE_CACHE) { | |
351 | uint i; | |
352 | ||
353 | if ((bp->pb_flags & PBF_MAPPED) && (bp->pb_page_count > 1)) | |
354 | free_address(bp->pb_addr - bp->pb_offset); | |
355 | ||
356 | for (i = 0; i < bp->pb_page_count; i++) | |
357 | page_cache_release(bp->pb_pages[i]); | |
358 | _pagebuf_free_pages(bp); | |
359 | } else if (bp->pb_flags & _PBF_KMEM_ALLOC) { | |
360 | /* | |
361 | * XXX(hch): bp->pb_count_desired might be incorrect (see | |
362 | * pagebuf_associate_memory for details), but fortunately | |
363 | * the Linux version of kmem_free ignores the len argument.. | |
364 | */ | |
365 | kmem_free(bp->pb_addr, bp->pb_count_desired); | |
366 | _pagebuf_free_pages(bp); | |
367 | } | |
368 | ||
369 | pagebuf_deallocate(bp); | |
370 | } | |
371 | ||
372 | /* | |
373 | * Finds all pages for buffer in question and builds it's page list. | |
374 | */ | |
375 | STATIC int | |
376 | _pagebuf_lookup_pages( | |
377 | xfs_buf_t *bp, | |
378 | uint flags) | |
379 | { | |
380 | struct address_space *mapping = bp->pb_target->pbr_mapping; | |
381 | size_t blocksize = bp->pb_target->pbr_bsize; | |
382 | size_t size = bp->pb_count_desired; | |
383 | size_t nbytes, offset; | |
384 | int gfp_mask = pb_to_gfp(flags); | |
385 | unsigned short page_count, i; | |
386 | pgoff_t first; | |
387 | loff_t end; | |
388 | int error; | |
389 | ||
390 | end = bp->pb_file_offset + bp->pb_buffer_length; | |
391 | page_count = page_buf_btoc(end) - page_buf_btoct(bp->pb_file_offset); | |
392 | ||
393 | error = _pagebuf_get_pages(bp, page_count, flags); | |
394 | if (unlikely(error)) | |
395 | return error; | |
396 | bp->pb_flags |= _PBF_PAGE_CACHE; | |
397 | ||
398 | offset = bp->pb_offset; | |
399 | first = bp->pb_file_offset >> PAGE_CACHE_SHIFT; | |
400 | ||
401 | for (i = 0; i < bp->pb_page_count; i++) { | |
402 | struct page *page; | |
403 | uint retries = 0; | |
404 | ||
405 | retry: | |
406 | page = find_or_create_page(mapping, first + i, gfp_mask); | |
407 | if (unlikely(page == NULL)) { | |
408 | if (flags & PBF_READ_AHEAD) { | |
409 | bp->pb_page_count = i; | |
410 | for (i = 0; i < bp->pb_page_count; i++) | |
411 | unlock_page(bp->pb_pages[i]); | |
412 | return -ENOMEM; | |
413 | } | |
414 | ||
415 | /* | |
416 | * This could deadlock. | |
417 | * | |
418 | * But until all the XFS lowlevel code is revamped to | |
419 | * handle buffer allocation failures we can't do much. | |
420 | */ | |
421 | if (!(++retries % 100)) | |
422 | printk(KERN_ERR | |
423 | "XFS: possible memory allocation " | |
424 | "deadlock in %s (mode:0x%x)\n", | |
425 | __FUNCTION__, gfp_mask); | |
426 | ||
427 | XFS_STATS_INC(pb_page_retries); | |
428 | pagebuf_daemon_wakeup(0, gfp_mask); | |
429 | blk_congestion_wait(WRITE, HZ/50); | |
430 | goto retry; | |
431 | } | |
432 | ||
433 | XFS_STATS_INC(pb_page_found); | |
434 | ||
435 | nbytes = min_t(size_t, size, PAGE_CACHE_SIZE - offset); | |
436 | size -= nbytes; | |
437 | ||
438 | if (!PageUptodate(page)) { | |
439 | page_count--; | |
440 | if (blocksize >= PAGE_CACHE_SIZE) { | |
441 | if (flags & PBF_READ) | |
442 | bp->pb_locked = 1; | |
443 | } else if (!PagePrivate(page)) { | |
444 | if (test_page_region(page, offset, nbytes)) | |
445 | page_count++; | |
446 | } | |
447 | } | |
448 | ||
449 | bp->pb_pages[i] = page; | |
450 | offset = 0; | |
451 | } | |
452 | ||
453 | if (!bp->pb_locked) { | |
454 | for (i = 0; i < bp->pb_page_count; i++) | |
455 | unlock_page(bp->pb_pages[i]); | |
456 | } | |
457 | ||
458 | if (page_count) { | |
459 | /* if we have any uptodate pages, mark that in the buffer */ | |
460 | bp->pb_flags &= ~PBF_NONE; | |
461 | ||
462 | /* if some pages aren't uptodate, mark that in the buffer */ | |
463 | if (page_count != bp->pb_page_count) | |
464 | bp->pb_flags |= PBF_PARTIAL; | |
465 | } | |
466 | ||
467 | PB_TRACE(bp, "lookup_pages", (long)page_count); | |
468 | return error; | |
469 | } | |
470 | ||
471 | /* | |
472 | * Map buffer into kernel address-space if nessecary. | |
473 | */ | |
474 | STATIC int | |
475 | _pagebuf_map_pages( | |
476 | xfs_buf_t *bp, | |
477 | uint flags) | |
478 | { | |
479 | /* A single page buffer is always mappable */ | |
480 | if (bp->pb_page_count == 1) { | |
481 | bp->pb_addr = page_address(bp->pb_pages[0]) + bp->pb_offset; | |
482 | bp->pb_flags |= PBF_MAPPED; | |
483 | } else if (flags & PBF_MAPPED) { | |
484 | if (as_list_len > 64) | |
485 | purge_addresses(); | |
486 | bp->pb_addr = vmap(bp->pb_pages, bp->pb_page_count, | |
487 | VM_MAP, PAGE_KERNEL); | |
488 | if (unlikely(bp->pb_addr == NULL)) | |
489 | return -ENOMEM; | |
490 | bp->pb_addr += bp->pb_offset; | |
491 | bp->pb_flags |= PBF_MAPPED; | |
492 | } | |
493 | ||
494 | return 0; | |
495 | } | |
496 | ||
497 | /* | |
498 | * Finding and Reading Buffers | |
499 | */ | |
500 | ||
501 | /* | |
502 | * _pagebuf_find | |
503 | * | |
504 | * Looks up, and creates if absent, a lockable buffer for | |
505 | * a given range of an inode. The buffer is returned | |
506 | * locked. If other overlapping buffers exist, they are | |
507 | * released before the new buffer is created and locked, | |
508 | * which may imply that this call will block until those buffers | |
509 | * are unlocked. No I/O is implied by this call. | |
510 | */ | |
511 | xfs_buf_t * | |
512 | _pagebuf_find( | |
513 | xfs_buftarg_t *btp, /* block device target */ | |
514 | loff_t ioff, /* starting offset of range */ | |
515 | size_t isize, /* length of range */ | |
516 | page_buf_flags_t flags, /* PBF_TRYLOCK */ | |
517 | xfs_buf_t *new_pb)/* newly allocated buffer */ | |
518 | { | |
519 | loff_t range_base; | |
520 | size_t range_length; | |
521 | xfs_bufhash_t *hash; | |
522 | xfs_buf_t *pb, *n; | |
523 | ||
524 | range_base = (ioff << BBSHIFT); | |
525 | range_length = (isize << BBSHIFT); | |
526 | ||
527 | /* Check for IOs smaller than the sector size / not sector aligned */ | |
528 | ASSERT(!(range_length < (1 << btp->pbr_sshift))); | |
529 | ASSERT(!(range_base & (loff_t)btp->pbr_smask)); | |
530 | ||
531 | hash = &btp->bt_hash[hash_long((unsigned long)ioff, btp->bt_hashshift)]; | |
532 | ||
533 | spin_lock(&hash->bh_lock); | |
534 | ||
535 | list_for_each_entry_safe(pb, n, &hash->bh_list, pb_hash_list) { | |
536 | ASSERT(btp == pb->pb_target); | |
537 | if (pb->pb_file_offset == range_base && | |
538 | pb->pb_buffer_length == range_length) { | |
539 | /* | |
540 | * If we look at something bring it to the | |
541 | * front of the list for next time. | |
542 | */ | |
543 | atomic_inc(&pb->pb_hold); | |
544 | list_move(&pb->pb_hash_list, &hash->bh_list); | |
545 | goto found; | |
546 | } | |
547 | } | |
548 | ||
549 | /* No match found */ | |
550 | if (new_pb) { | |
551 | _pagebuf_initialize(new_pb, btp, range_base, | |
552 | range_length, flags); | |
553 | new_pb->pb_hash = hash; | |
554 | list_add(&new_pb->pb_hash_list, &hash->bh_list); | |
555 | } else { | |
556 | XFS_STATS_INC(pb_miss_locked); | |
557 | } | |
558 | ||
559 | spin_unlock(&hash->bh_lock); | |
560 | return new_pb; | |
561 | ||
562 | found: | |
563 | spin_unlock(&hash->bh_lock); | |
564 | ||
565 | /* Attempt to get the semaphore without sleeping, | |
566 | * if this does not work then we need to drop the | |
567 | * spinlock and do a hard attempt on the semaphore. | |
568 | */ | |
569 | if (down_trylock(&pb->pb_sema)) { | |
570 | if (!(flags & PBF_TRYLOCK)) { | |
571 | /* wait for buffer ownership */ | |
572 | PB_TRACE(pb, "get_lock", 0); | |
573 | pagebuf_lock(pb); | |
574 | XFS_STATS_INC(pb_get_locked_waited); | |
575 | } else { | |
576 | /* We asked for a trylock and failed, no need | |
577 | * to look at file offset and length here, we | |
578 | * know that this pagebuf at least overlaps our | |
579 | * pagebuf and is locked, therefore our buffer | |
580 | * either does not exist, or is this buffer | |
581 | */ | |
582 | ||
583 | pagebuf_rele(pb); | |
584 | XFS_STATS_INC(pb_busy_locked); | |
585 | return (NULL); | |
586 | } | |
587 | } else { | |
588 | /* trylock worked */ | |
589 | PB_SET_OWNER(pb); | |
590 | } | |
591 | ||
592 | if (pb->pb_flags & PBF_STALE) | |
593 | pb->pb_flags &= PBF_MAPPED; | |
594 | PB_TRACE(pb, "got_lock", 0); | |
595 | XFS_STATS_INC(pb_get_locked); | |
596 | return (pb); | |
597 | } | |
598 | ||
599 | /* | |
600 | * xfs_buf_get_flags assembles a buffer covering the specified range. | |
601 | * | |
602 | * Storage in memory for all portions of the buffer will be allocated, | |
603 | * although backing storage may not be. | |
604 | */ | |
605 | xfs_buf_t * | |
606 | xfs_buf_get_flags( /* allocate a buffer */ | |
607 | xfs_buftarg_t *target,/* target for buffer */ | |
608 | loff_t ioff, /* starting offset of range */ | |
609 | size_t isize, /* length of range */ | |
610 | page_buf_flags_t flags) /* PBF_TRYLOCK */ | |
611 | { | |
612 | xfs_buf_t *pb, *new_pb; | |
613 | int error = 0, i; | |
614 | ||
615 | new_pb = pagebuf_allocate(flags); | |
616 | if (unlikely(!new_pb)) | |
617 | return NULL; | |
618 | ||
619 | pb = _pagebuf_find(target, ioff, isize, flags, new_pb); | |
620 | if (pb == new_pb) { | |
621 | error = _pagebuf_lookup_pages(pb, flags); | |
622 | if (error) | |
623 | goto no_buffer; | |
624 | } else { | |
625 | pagebuf_deallocate(new_pb); | |
626 | if (unlikely(pb == NULL)) | |
627 | return NULL; | |
628 | } | |
629 | ||
630 | for (i = 0; i < pb->pb_page_count; i++) | |
631 | mark_page_accessed(pb->pb_pages[i]); | |
632 | ||
633 | if (!(pb->pb_flags & PBF_MAPPED)) { | |
634 | error = _pagebuf_map_pages(pb, flags); | |
635 | if (unlikely(error)) { | |
636 | printk(KERN_WARNING "%s: failed to map pages\n", | |
637 | __FUNCTION__); | |
638 | goto no_buffer; | |
639 | } | |
640 | } | |
641 | ||
642 | XFS_STATS_INC(pb_get); | |
643 | ||
644 | /* | |
645 | * Always fill in the block number now, the mapped cases can do | |
646 | * their own overlay of this later. | |
647 | */ | |
648 | pb->pb_bn = ioff; | |
649 | pb->pb_count_desired = pb->pb_buffer_length; | |
650 | ||
651 | PB_TRACE(pb, "get", (unsigned long)flags); | |
652 | return pb; | |
653 | ||
654 | no_buffer: | |
655 | if (flags & (PBF_LOCK | PBF_TRYLOCK)) | |
656 | pagebuf_unlock(pb); | |
657 | pagebuf_rele(pb); | |
658 | return NULL; | |
659 | } | |
660 | ||
661 | xfs_buf_t * | |
662 | xfs_buf_read_flags( | |
663 | xfs_buftarg_t *target, | |
664 | loff_t ioff, | |
665 | size_t isize, | |
666 | page_buf_flags_t flags) | |
667 | { | |
668 | xfs_buf_t *pb; | |
669 | ||
670 | flags |= PBF_READ; | |
671 | ||
672 | pb = xfs_buf_get_flags(target, ioff, isize, flags); | |
673 | if (pb) { | |
674 | if (PBF_NOT_DONE(pb)) { | |
675 | PB_TRACE(pb, "read", (unsigned long)flags); | |
676 | XFS_STATS_INC(pb_get_read); | |
677 | pagebuf_iostart(pb, flags); | |
678 | } else if (flags & PBF_ASYNC) { | |
679 | PB_TRACE(pb, "read_async", (unsigned long)flags); | |
680 | /* | |
681 | * Read ahead call which is already satisfied, | |
682 | * drop the buffer | |
683 | */ | |
684 | goto no_buffer; | |
685 | } else { | |
686 | PB_TRACE(pb, "read_done", (unsigned long)flags); | |
687 | /* We do not want read in the flags */ | |
688 | pb->pb_flags &= ~PBF_READ; | |
689 | } | |
690 | } | |
691 | ||
692 | return pb; | |
693 | ||
694 | no_buffer: | |
695 | if (flags & (PBF_LOCK | PBF_TRYLOCK)) | |
696 | pagebuf_unlock(pb); | |
697 | pagebuf_rele(pb); | |
698 | return NULL; | |
699 | } | |
700 | ||
701 | /* | |
702 | * Create a skeletal pagebuf (no pages associated with it). | |
703 | */ | |
704 | xfs_buf_t * | |
705 | pagebuf_lookup( | |
706 | xfs_buftarg_t *target, | |
707 | loff_t ioff, | |
708 | size_t isize, | |
709 | page_buf_flags_t flags) | |
710 | { | |
711 | xfs_buf_t *pb; | |
712 | ||
713 | pb = pagebuf_allocate(flags); | |
714 | if (pb) { | |
715 | _pagebuf_initialize(pb, target, ioff, isize, flags); | |
716 | } | |
717 | return pb; | |
718 | } | |
719 | ||
720 | /* | |
721 | * If we are not low on memory then do the readahead in a deadlock | |
722 | * safe manner. | |
723 | */ | |
724 | void | |
725 | pagebuf_readahead( | |
726 | xfs_buftarg_t *target, | |
727 | loff_t ioff, | |
728 | size_t isize, | |
729 | page_buf_flags_t flags) | |
730 | { | |
731 | struct backing_dev_info *bdi; | |
732 | ||
733 | bdi = target->pbr_mapping->backing_dev_info; | |
734 | if (bdi_read_congested(bdi)) | |
735 | return; | |
736 | ||
737 | flags |= (PBF_TRYLOCK|PBF_ASYNC|PBF_READ_AHEAD); | |
738 | xfs_buf_read_flags(target, ioff, isize, flags); | |
739 | } | |
740 | ||
741 | xfs_buf_t * | |
742 | pagebuf_get_empty( | |
743 | size_t len, | |
744 | xfs_buftarg_t *target) | |
745 | { | |
746 | xfs_buf_t *pb; | |
747 | ||
748 | pb = pagebuf_allocate(0); | |
749 | if (pb) | |
750 | _pagebuf_initialize(pb, target, 0, len, 0); | |
751 | return pb; | |
752 | } | |
753 | ||
754 | static inline struct page * | |
755 | mem_to_page( | |
756 | void *addr) | |
757 | { | |
758 | if (((unsigned long)addr < VMALLOC_START) || | |
759 | ((unsigned long)addr >= VMALLOC_END)) { | |
760 | return virt_to_page(addr); | |
761 | } else { | |
762 | return vmalloc_to_page(addr); | |
763 | } | |
764 | } | |
765 | ||
766 | int | |
767 | pagebuf_associate_memory( | |
768 | xfs_buf_t *pb, | |
769 | void *mem, | |
770 | size_t len) | |
771 | { | |
772 | int rval; | |
773 | int i = 0; | |
774 | size_t ptr; | |
775 | size_t end, end_cur; | |
776 | off_t offset; | |
777 | int page_count; | |
778 | ||
779 | page_count = PAGE_CACHE_ALIGN(len) >> PAGE_CACHE_SHIFT; | |
780 | offset = (off_t) mem - ((off_t)mem & PAGE_CACHE_MASK); | |
781 | if (offset && (len > PAGE_CACHE_SIZE)) | |
782 | page_count++; | |
783 | ||
784 | /* Free any previous set of page pointers */ | |
785 | if (pb->pb_pages) | |
786 | _pagebuf_free_pages(pb); | |
787 | ||
788 | pb->pb_pages = NULL; | |
789 | pb->pb_addr = mem; | |
790 | ||
791 | rval = _pagebuf_get_pages(pb, page_count, 0); | |
792 | if (rval) | |
793 | return rval; | |
794 | ||
795 | pb->pb_offset = offset; | |
796 | ptr = (size_t) mem & PAGE_CACHE_MASK; | |
797 | end = PAGE_CACHE_ALIGN((size_t) mem + len); | |
798 | end_cur = end; | |
799 | /* set up first page */ | |
800 | pb->pb_pages[0] = mem_to_page(mem); | |
801 | ||
802 | ptr += PAGE_CACHE_SIZE; | |
803 | pb->pb_page_count = ++i; | |
804 | while (ptr < end) { | |
805 | pb->pb_pages[i] = mem_to_page((void *)ptr); | |
806 | pb->pb_page_count = ++i; | |
807 | ptr += PAGE_CACHE_SIZE; | |
808 | } | |
809 | pb->pb_locked = 0; | |
810 | ||
811 | pb->pb_count_desired = pb->pb_buffer_length = len; | |
812 | pb->pb_flags |= PBF_MAPPED; | |
813 | ||
814 | return 0; | |
815 | } | |
816 | ||
817 | xfs_buf_t * | |
818 | pagebuf_get_no_daddr( | |
819 | size_t len, | |
820 | xfs_buftarg_t *target) | |
821 | { | |
822 | size_t malloc_len = len; | |
823 | xfs_buf_t *bp; | |
824 | void *data; | |
825 | int error; | |
826 | ||
827 | bp = pagebuf_allocate(0); | |
828 | if (unlikely(bp == NULL)) | |
829 | goto fail; | |
830 | _pagebuf_initialize(bp, target, 0, len, PBF_FORCEIO); | |
831 | ||
832 | try_again: | |
833 | data = kmem_alloc(malloc_len, KM_SLEEP | KM_MAYFAIL); | |
834 | if (unlikely(data == NULL)) | |
835 | goto fail_free_buf; | |
836 | ||
837 | /* check whether alignment matches.. */ | |
838 | if ((__psunsigned_t)data != | |
839 | ((__psunsigned_t)data & ~target->pbr_smask)) { | |
840 | /* .. else double the size and try again */ | |
841 | kmem_free(data, malloc_len); | |
842 | malloc_len <<= 1; | |
843 | goto try_again; | |
844 | } | |
845 | ||
846 | error = pagebuf_associate_memory(bp, data, len); | |
847 | if (error) | |
848 | goto fail_free_mem; | |
849 | bp->pb_flags |= _PBF_KMEM_ALLOC; | |
850 | ||
851 | pagebuf_unlock(bp); | |
852 | ||
853 | PB_TRACE(bp, "no_daddr", data); | |
854 | return bp; | |
855 | fail_free_mem: | |
856 | kmem_free(data, malloc_len); | |
857 | fail_free_buf: | |
858 | pagebuf_free(bp); | |
859 | fail: | |
860 | return NULL; | |
861 | } | |
862 | ||
863 | /* | |
864 | * pagebuf_hold | |
865 | * | |
866 | * Increment reference count on buffer, to hold the buffer concurrently | |
867 | * with another thread which may release (free) the buffer asynchronously. | |
868 | * | |
869 | * Must hold the buffer already to call this function. | |
870 | */ | |
871 | void | |
872 | pagebuf_hold( | |
873 | xfs_buf_t *pb) | |
874 | { | |
875 | atomic_inc(&pb->pb_hold); | |
876 | PB_TRACE(pb, "hold", 0); | |
877 | } | |
878 | ||
879 | /* | |
880 | * pagebuf_rele | |
881 | * | |
882 | * pagebuf_rele releases a hold on the specified buffer. If the | |
883 | * the hold count is 1, pagebuf_rele calls pagebuf_free. | |
884 | */ | |
885 | void | |
886 | pagebuf_rele( | |
887 | xfs_buf_t *pb) | |
888 | { | |
889 | xfs_bufhash_t *hash = pb->pb_hash; | |
890 | ||
891 | PB_TRACE(pb, "rele", pb->pb_relse); | |
892 | ||
893 | /* | |
894 | * pagebuf_lookup buffers are not hashed, not delayed write, | |
895 | * and don't have their own release routines. Special case. | |
896 | */ | |
897 | if (unlikely(!hash)) { | |
898 | ASSERT(!pb->pb_relse); | |
899 | if (atomic_dec_and_test(&pb->pb_hold)) | |
900 | xfs_buf_free(pb); | |
901 | return; | |
902 | } | |
903 | ||
904 | if (atomic_dec_and_lock(&pb->pb_hold, &hash->bh_lock)) { | |
905 | int do_free = 1; | |
906 | ||
907 | if (pb->pb_relse) { | |
908 | atomic_inc(&pb->pb_hold); | |
909 | spin_unlock(&hash->bh_lock); | |
910 | (*(pb->pb_relse)) (pb); | |
911 | spin_lock(&hash->bh_lock); | |
912 | do_free = 0; | |
913 | } | |
914 | ||
915 | if (pb->pb_flags & PBF_DELWRI) { | |
916 | pb->pb_flags |= PBF_ASYNC; | |
917 | atomic_inc(&pb->pb_hold); | |
918 | pagebuf_delwri_queue(pb, 0); | |
919 | do_free = 0; | |
920 | } else if (pb->pb_flags & PBF_FS_MANAGED) { | |
921 | do_free = 0; | |
922 | } | |
923 | ||
924 | if (do_free) { | |
925 | list_del_init(&pb->pb_hash_list); | |
926 | spin_unlock(&hash->bh_lock); | |
927 | pagebuf_free(pb); | |
928 | } else { | |
929 | spin_unlock(&hash->bh_lock); | |
930 | } | |
931 | } | |
932 | } | |
933 | ||
934 | ||
935 | /* | |
936 | * Mutual exclusion on buffers. Locking model: | |
937 | * | |
938 | * Buffers associated with inodes for which buffer locking | |
939 | * is not enabled are not protected by semaphores, and are | |
940 | * assumed to be exclusively owned by the caller. There is a | |
941 | * spinlock in the buffer, used by the caller when concurrent | |
942 | * access is possible. | |
943 | */ | |
944 | ||
945 | /* | |
946 | * pagebuf_cond_lock | |
947 | * | |
948 | * pagebuf_cond_lock locks a buffer object, if it is not already locked. | |
949 | * Note that this in no way | |
950 | * locks the underlying pages, so it is only useful for synchronizing | |
951 | * concurrent use of page buffer objects, not for synchronizing independent | |
952 | * access to the underlying pages. | |
953 | */ | |
954 | int | |
955 | pagebuf_cond_lock( /* lock buffer, if not locked */ | |
956 | /* returns -EBUSY if locked) */ | |
957 | xfs_buf_t *pb) | |
958 | { | |
959 | int locked; | |
960 | ||
961 | locked = down_trylock(&pb->pb_sema) == 0; | |
962 | if (locked) { | |
963 | PB_SET_OWNER(pb); | |
964 | } | |
965 | PB_TRACE(pb, "cond_lock", (long)locked); | |
966 | return(locked ? 0 : -EBUSY); | |
967 | } | |
968 | ||
969 | #if defined(DEBUG) || defined(XFS_BLI_TRACE) | |
970 | /* | |
971 | * pagebuf_lock_value | |
972 | * | |
973 | * Return lock value for a pagebuf | |
974 | */ | |
975 | int | |
976 | pagebuf_lock_value( | |
977 | xfs_buf_t *pb) | |
978 | { | |
979 | return(atomic_read(&pb->pb_sema.count)); | |
980 | } | |
981 | #endif | |
982 | ||
983 | /* | |
984 | * pagebuf_lock | |
985 | * | |
986 | * pagebuf_lock locks a buffer object. Note that this in no way | |
987 | * locks the underlying pages, so it is only useful for synchronizing | |
988 | * concurrent use of page buffer objects, not for synchronizing independent | |
989 | * access to the underlying pages. | |
990 | */ | |
991 | int | |
992 | pagebuf_lock( | |
993 | xfs_buf_t *pb) | |
994 | { | |
995 | PB_TRACE(pb, "lock", 0); | |
996 | if (atomic_read(&pb->pb_io_remaining)) | |
997 | blk_run_address_space(pb->pb_target->pbr_mapping); | |
998 | down(&pb->pb_sema); | |
999 | PB_SET_OWNER(pb); | |
1000 | PB_TRACE(pb, "locked", 0); | |
1001 | return 0; | |
1002 | } | |
1003 | ||
1004 | /* | |
1005 | * pagebuf_unlock | |
1006 | * | |
1007 | * pagebuf_unlock releases the lock on the buffer object created by | |
1008 | * pagebuf_lock or pagebuf_cond_lock (not any | |
1009 | * pinning of underlying pages created by pagebuf_pin). | |
1010 | */ | |
1011 | void | |
1012 | pagebuf_unlock( /* unlock buffer */ | |
1013 | xfs_buf_t *pb) /* buffer to unlock */ | |
1014 | { | |
1015 | PB_CLEAR_OWNER(pb); | |
1016 | up(&pb->pb_sema); | |
1017 | PB_TRACE(pb, "unlock", 0); | |
1018 | } | |
1019 | ||
1020 | ||
1021 | /* | |
1022 | * Pinning Buffer Storage in Memory | |
1023 | */ | |
1024 | ||
1025 | /* | |
1026 | * pagebuf_pin | |
1027 | * | |
1028 | * pagebuf_pin locks all of the memory represented by a buffer in | |
1029 | * memory. Multiple calls to pagebuf_pin and pagebuf_unpin, for | |
1030 | * the same or different buffers affecting a given page, will | |
1031 | * properly count the number of outstanding "pin" requests. The | |
1032 | * buffer may be released after the pagebuf_pin and a different | |
1033 | * buffer used when calling pagebuf_unpin, if desired. | |
1034 | * pagebuf_pin should be used by the file system when it wants be | |
1035 | * assured that no attempt will be made to force the affected | |
1036 | * memory to disk. It does not assure that a given logical page | |
1037 | * will not be moved to a different physical page. | |
1038 | */ | |
1039 | void | |
1040 | pagebuf_pin( | |
1041 | xfs_buf_t *pb) | |
1042 | { | |
1043 | atomic_inc(&pb->pb_pin_count); | |
1044 | PB_TRACE(pb, "pin", (long)pb->pb_pin_count.counter); | |
1045 | } | |
1046 | ||
1047 | /* | |
1048 | * pagebuf_unpin | |
1049 | * | |
1050 | * pagebuf_unpin reverses the locking of memory performed by | |
1051 | * pagebuf_pin. Note that both functions affected the logical | |
1052 | * pages associated with the buffer, not the buffer itself. | |
1053 | */ | |
1054 | void | |
1055 | pagebuf_unpin( | |
1056 | xfs_buf_t *pb) | |
1057 | { | |
1058 | if (atomic_dec_and_test(&pb->pb_pin_count)) { | |
1059 | wake_up_all(&pb->pb_waiters); | |
1060 | } | |
1061 | PB_TRACE(pb, "unpin", (long)pb->pb_pin_count.counter); | |
1062 | } | |
1063 | ||
1064 | int | |
1065 | pagebuf_ispin( | |
1066 | xfs_buf_t *pb) | |
1067 | { | |
1068 | return atomic_read(&pb->pb_pin_count); | |
1069 | } | |
1070 | ||
1071 | /* | |
1072 | * pagebuf_wait_unpin | |
1073 | * | |
1074 | * pagebuf_wait_unpin waits until all of the memory associated | |
1075 | * with the buffer is not longer locked in memory. It returns | |
1076 | * immediately if none of the affected pages are locked. | |
1077 | */ | |
1078 | static inline void | |
1079 | _pagebuf_wait_unpin( | |
1080 | xfs_buf_t *pb) | |
1081 | { | |
1082 | DECLARE_WAITQUEUE (wait, current); | |
1083 | ||
1084 | if (atomic_read(&pb->pb_pin_count) == 0) | |
1085 | return; | |
1086 | ||
1087 | add_wait_queue(&pb->pb_waiters, &wait); | |
1088 | for (;;) { | |
1089 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1090 | if (atomic_read(&pb->pb_pin_count) == 0) | |
1091 | break; | |
1092 | if (atomic_read(&pb->pb_io_remaining)) | |
1093 | blk_run_address_space(pb->pb_target->pbr_mapping); | |
1094 | schedule(); | |
1095 | } | |
1096 | remove_wait_queue(&pb->pb_waiters, &wait); | |
1097 | set_current_state(TASK_RUNNING); | |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * Buffer Utility Routines | |
1102 | */ | |
1103 | ||
1104 | /* | |
1105 | * pagebuf_iodone | |
1106 | * | |
1107 | * pagebuf_iodone marks a buffer for which I/O is in progress | |
1108 | * done with respect to that I/O. The pb_iodone routine, if | |
1109 | * present, will be called as a side-effect. | |
1110 | */ | |
1111 | STATIC void | |
1112 | pagebuf_iodone_work( | |
1113 | void *v) | |
1114 | { | |
1115 | xfs_buf_t *bp = (xfs_buf_t *)v; | |
1116 | ||
1117 | if (bp->pb_iodone) | |
1118 | (*(bp->pb_iodone))(bp); | |
1119 | else if (bp->pb_flags & PBF_ASYNC) | |
1120 | xfs_buf_relse(bp); | |
1121 | } | |
1122 | ||
1123 | void | |
1124 | pagebuf_iodone( | |
1125 | xfs_buf_t *pb, | |
1126 | int dataio, | |
1127 | int schedule) | |
1128 | { | |
1129 | pb->pb_flags &= ~(PBF_READ | PBF_WRITE); | |
1130 | if (pb->pb_error == 0) { | |
1131 | pb->pb_flags &= ~(PBF_PARTIAL | PBF_NONE); | |
1132 | } | |
1133 | ||
1134 | PB_TRACE(pb, "iodone", pb->pb_iodone); | |
1135 | ||
1136 | if ((pb->pb_iodone) || (pb->pb_flags & PBF_ASYNC)) { | |
1137 | if (schedule) { | |
1138 | INIT_WORK(&pb->pb_iodone_work, pagebuf_iodone_work, pb); | |
1139 | queue_work(dataio ? pagebuf_dataio_workqueue : | |
1140 | pagebuf_logio_workqueue, &pb->pb_iodone_work); | |
1141 | } else { | |
1142 | pagebuf_iodone_work(pb); | |
1143 | } | |
1144 | } else { | |
1145 | up(&pb->pb_iodonesema); | |
1146 | } | |
1147 | } | |
1148 | ||
1149 | /* | |
1150 | * pagebuf_ioerror | |
1151 | * | |
1152 | * pagebuf_ioerror sets the error code for a buffer. | |
1153 | */ | |
1154 | void | |
1155 | pagebuf_ioerror( /* mark/clear buffer error flag */ | |
1156 | xfs_buf_t *pb, /* buffer to mark */ | |
1157 | int error) /* error to store (0 if none) */ | |
1158 | { | |
1159 | ASSERT(error >= 0 && error <= 0xffff); | |
1160 | pb->pb_error = (unsigned short)error; | |
1161 | PB_TRACE(pb, "ioerror", (unsigned long)error); | |
1162 | } | |
1163 | ||
1164 | /* | |
1165 | * pagebuf_iostart | |
1166 | * | |
1167 | * pagebuf_iostart initiates I/O on a buffer, based on the flags supplied. | |
1168 | * If necessary, it will arrange for any disk space allocation required, | |
1169 | * and it will break up the request if the block mappings require it. | |
1170 | * The pb_iodone routine in the buffer supplied will only be called | |
1171 | * when all of the subsidiary I/O requests, if any, have been completed. | |
1172 | * pagebuf_iostart calls the pagebuf_ioinitiate routine or | |
1173 | * pagebuf_iorequest, if the former routine is not defined, to start | |
1174 | * the I/O on a given low-level request. | |
1175 | */ | |
1176 | int | |
1177 | pagebuf_iostart( /* start I/O on a buffer */ | |
1178 | xfs_buf_t *pb, /* buffer to start */ | |
1179 | page_buf_flags_t flags) /* PBF_LOCK, PBF_ASYNC, PBF_READ, */ | |
1180 | /* PBF_WRITE, PBF_DELWRI, */ | |
1181 | /* PBF_DONT_BLOCK */ | |
1182 | { | |
1183 | int status = 0; | |
1184 | ||
1185 | PB_TRACE(pb, "iostart", (unsigned long)flags); | |
1186 | ||
1187 | if (flags & PBF_DELWRI) { | |
1188 | pb->pb_flags &= ~(PBF_READ | PBF_WRITE | PBF_ASYNC); | |
1189 | pb->pb_flags |= flags & (PBF_DELWRI | PBF_ASYNC); | |
1190 | pagebuf_delwri_queue(pb, 1); | |
1191 | return status; | |
1192 | } | |
1193 | ||
1194 | pb->pb_flags &= ~(PBF_READ | PBF_WRITE | PBF_ASYNC | PBF_DELWRI | \ | |
1195 | PBF_READ_AHEAD | _PBF_RUN_QUEUES); | |
1196 | pb->pb_flags |= flags & (PBF_READ | PBF_WRITE | PBF_ASYNC | \ | |
1197 | PBF_READ_AHEAD | _PBF_RUN_QUEUES); | |
1198 | ||
1199 | BUG_ON(pb->pb_bn == XFS_BUF_DADDR_NULL); | |
1200 | ||
1201 | /* For writes allow an alternate strategy routine to precede | |
1202 | * the actual I/O request (which may not be issued at all in | |
1203 | * a shutdown situation, for example). | |
1204 | */ | |
1205 | status = (flags & PBF_WRITE) ? | |
1206 | pagebuf_iostrategy(pb) : pagebuf_iorequest(pb); | |
1207 | ||
1208 | /* Wait for I/O if we are not an async request. | |
1209 | * Note: async I/O request completion will release the buffer, | |
1210 | * and that can already be done by this point. So using the | |
1211 | * buffer pointer from here on, after async I/O, is invalid. | |
1212 | */ | |
1213 | if (!status && !(flags & PBF_ASYNC)) | |
1214 | status = pagebuf_iowait(pb); | |
1215 | ||
1216 | return status; | |
1217 | } | |
1218 | ||
1219 | /* | |
1220 | * Helper routine for pagebuf_iorequest | |
1221 | */ | |
1222 | ||
1223 | STATIC __inline__ int | |
1224 | _pagebuf_iolocked( | |
1225 | xfs_buf_t *pb) | |
1226 | { | |
1227 | ASSERT(pb->pb_flags & (PBF_READ|PBF_WRITE)); | |
1228 | if (pb->pb_flags & PBF_READ) | |
1229 | return pb->pb_locked; | |
1230 | return 0; | |
1231 | } | |
1232 | ||
1233 | STATIC __inline__ void | |
1234 | _pagebuf_iodone( | |
1235 | xfs_buf_t *pb, | |
1236 | int schedule) | |
1237 | { | |
1238 | if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) { | |
1239 | pb->pb_locked = 0; | |
1240 | pagebuf_iodone(pb, (pb->pb_flags & PBF_FS_DATAIOD), schedule); | |
1241 | } | |
1242 | } | |
1243 | ||
1244 | STATIC int | |
1245 | bio_end_io_pagebuf( | |
1246 | struct bio *bio, | |
1247 | unsigned int bytes_done, | |
1248 | int error) | |
1249 | { | |
1250 | xfs_buf_t *pb = (xfs_buf_t *)bio->bi_private; | |
1251 | unsigned int i, blocksize = pb->pb_target->pbr_bsize; | |
1252 | struct bio_vec *bvec = bio->bi_io_vec; | |
1253 | ||
1254 | if (bio->bi_size) | |
1255 | return 1; | |
1256 | ||
1257 | if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
1258 | pb->pb_error = EIO; | |
1259 | ||
1260 | for (i = 0; i < bio->bi_vcnt; i++, bvec++) { | |
1261 | struct page *page = bvec->bv_page; | |
1262 | ||
1263 | if (pb->pb_error) { | |
1264 | SetPageError(page); | |
1265 | } else if (blocksize == PAGE_CACHE_SIZE) { | |
1266 | SetPageUptodate(page); | |
1267 | } else if (!PagePrivate(page) && | |
1268 | (pb->pb_flags & _PBF_PAGE_CACHE)) { | |
1269 | set_page_region(page, bvec->bv_offset, bvec->bv_len); | |
1270 | } | |
1271 | ||
1272 | if (_pagebuf_iolocked(pb)) { | |
1273 | unlock_page(page); | |
1274 | } | |
1275 | } | |
1276 | ||
1277 | _pagebuf_iodone(pb, 1); | |
1278 | bio_put(bio); | |
1279 | return 0; | |
1280 | } | |
1281 | ||
1282 | STATIC void | |
1283 | _pagebuf_ioapply( | |
1284 | xfs_buf_t *pb) | |
1285 | { | |
1286 | int i, rw, map_i, total_nr_pages, nr_pages; | |
1287 | struct bio *bio; | |
1288 | int offset = pb->pb_offset; | |
1289 | int size = pb->pb_count_desired; | |
1290 | sector_t sector = pb->pb_bn; | |
1291 | unsigned int blocksize = pb->pb_target->pbr_bsize; | |
1292 | int locking = _pagebuf_iolocked(pb); | |
1293 | ||
1294 | total_nr_pages = pb->pb_page_count; | |
1295 | map_i = 0; | |
1296 | ||
1297 | if (pb->pb_flags & _PBF_RUN_QUEUES) { | |
1298 | pb->pb_flags &= ~_PBF_RUN_QUEUES; | |
1299 | rw = (pb->pb_flags & PBF_READ) ? READ_SYNC : WRITE_SYNC; | |
1300 | } else { | |
1301 | rw = (pb->pb_flags & PBF_READ) ? READ : WRITE; | |
1302 | } | |
1303 | ||
1304 | /* Special code path for reading a sub page size pagebuf in -- | |
1305 | * we populate up the whole page, and hence the other metadata | |
1306 | * in the same page. This optimization is only valid when the | |
1307 | * filesystem block size and the page size are equal. | |
1308 | */ | |
1309 | if ((pb->pb_buffer_length < PAGE_CACHE_SIZE) && | |
1310 | (pb->pb_flags & PBF_READ) && locking && | |
1311 | (blocksize == PAGE_CACHE_SIZE)) { | |
1312 | bio = bio_alloc(GFP_NOIO, 1); | |
1313 | ||
1314 | bio->bi_bdev = pb->pb_target->pbr_bdev; | |
1315 | bio->bi_sector = sector - (offset >> BBSHIFT); | |
1316 | bio->bi_end_io = bio_end_io_pagebuf; | |
1317 | bio->bi_private = pb; | |
1318 | ||
1319 | bio_add_page(bio, pb->pb_pages[0], PAGE_CACHE_SIZE, 0); | |
1320 | size = 0; | |
1321 | ||
1322 | atomic_inc(&pb->pb_io_remaining); | |
1323 | ||
1324 | goto submit_io; | |
1325 | } | |
1326 | ||
1327 | /* Lock down the pages which we need to for the request */ | |
1328 | if (locking && (pb->pb_flags & PBF_WRITE) && (pb->pb_locked == 0)) { | |
1329 | for (i = 0; size; i++) { | |
1330 | int nbytes = PAGE_CACHE_SIZE - offset; | |
1331 | struct page *page = pb->pb_pages[i]; | |
1332 | ||
1333 | if (nbytes > size) | |
1334 | nbytes = size; | |
1335 | ||
1336 | lock_page(page); | |
1337 | ||
1338 | size -= nbytes; | |
1339 | offset = 0; | |
1340 | } | |
1341 | offset = pb->pb_offset; | |
1342 | size = pb->pb_count_desired; | |
1343 | } | |
1344 | ||
1345 | next_chunk: | |
1346 | atomic_inc(&pb->pb_io_remaining); | |
1347 | nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT); | |
1348 | if (nr_pages > total_nr_pages) | |
1349 | nr_pages = total_nr_pages; | |
1350 | ||
1351 | bio = bio_alloc(GFP_NOIO, nr_pages); | |
1352 | bio->bi_bdev = pb->pb_target->pbr_bdev; | |
1353 | bio->bi_sector = sector; | |
1354 | bio->bi_end_io = bio_end_io_pagebuf; | |
1355 | bio->bi_private = pb; | |
1356 | ||
1357 | for (; size && nr_pages; nr_pages--, map_i++) { | |
1358 | int nbytes = PAGE_CACHE_SIZE - offset; | |
1359 | ||
1360 | if (nbytes > size) | |
1361 | nbytes = size; | |
1362 | ||
1363 | if (bio_add_page(bio, pb->pb_pages[map_i], | |
1364 | nbytes, offset) < nbytes) | |
1365 | break; | |
1366 | ||
1367 | offset = 0; | |
1368 | sector += nbytes >> BBSHIFT; | |
1369 | size -= nbytes; | |
1370 | total_nr_pages--; | |
1371 | } | |
1372 | ||
1373 | submit_io: | |
1374 | if (likely(bio->bi_size)) { | |
1375 | submit_bio(rw, bio); | |
1376 | if (size) | |
1377 | goto next_chunk; | |
1378 | } else { | |
1379 | bio_put(bio); | |
1380 | pagebuf_ioerror(pb, EIO); | |
1381 | } | |
1382 | } | |
1383 | ||
1384 | /* | |
1385 | * pagebuf_iorequest -- the core I/O request routine. | |
1386 | */ | |
1387 | int | |
1388 | pagebuf_iorequest( /* start real I/O */ | |
1389 | xfs_buf_t *pb) /* buffer to convey to device */ | |
1390 | { | |
1391 | PB_TRACE(pb, "iorequest", 0); | |
1392 | ||
1393 | if (pb->pb_flags & PBF_DELWRI) { | |
1394 | pagebuf_delwri_queue(pb, 1); | |
1395 | return 0; | |
1396 | } | |
1397 | ||
1398 | if (pb->pb_flags & PBF_WRITE) { | |
1399 | _pagebuf_wait_unpin(pb); | |
1400 | } | |
1401 | ||
1402 | pagebuf_hold(pb); | |
1403 | ||
1404 | /* Set the count to 1 initially, this will stop an I/O | |
1405 | * completion callout which happens before we have started | |
1406 | * all the I/O from calling pagebuf_iodone too early. | |
1407 | */ | |
1408 | atomic_set(&pb->pb_io_remaining, 1); | |
1409 | _pagebuf_ioapply(pb); | |
1410 | _pagebuf_iodone(pb, 0); | |
1411 | ||
1412 | pagebuf_rele(pb); | |
1413 | return 0; | |
1414 | } | |
1415 | ||
1416 | /* | |
1417 | * pagebuf_iowait | |
1418 | * | |
1419 | * pagebuf_iowait waits for I/O to complete on the buffer supplied. | |
1420 | * It returns immediately if no I/O is pending. In any case, it returns | |
1421 | * the error code, if any, or 0 if there is no error. | |
1422 | */ | |
1423 | int | |
1424 | pagebuf_iowait( | |
1425 | xfs_buf_t *pb) | |
1426 | { | |
1427 | PB_TRACE(pb, "iowait", 0); | |
1428 | if (atomic_read(&pb->pb_io_remaining)) | |
1429 | blk_run_address_space(pb->pb_target->pbr_mapping); | |
1430 | down(&pb->pb_iodonesema); | |
1431 | PB_TRACE(pb, "iowaited", (long)pb->pb_error); | |
1432 | return pb->pb_error; | |
1433 | } | |
1434 | ||
1435 | caddr_t | |
1436 | pagebuf_offset( | |
1437 | xfs_buf_t *pb, | |
1438 | size_t offset) | |
1439 | { | |
1440 | struct page *page; | |
1441 | ||
1442 | offset += pb->pb_offset; | |
1443 | ||
1444 | page = pb->pb_pages[offset >> PAGE_CACHE_SHIFT]; | |
1445 | return (caddr_t) page_address(page) + (offset & (PAGE_CACHE_SIZE - 1)); | |
1446 | } | |
1447 | ||
1448 | /* | |
1449 | * pagebuf_iomove | |
1450 | * | |
1451 | * Move data into or out of a buffer. | |
1452 | */ | |
1453 | void | |
1454 | pagebuf_iomove( | |
1455 | xfs_buf_t *pb, /* buffer to process */ | |
1456 | size_t boff, /* starting buffer offset */ | |
1457 | size_t bsize, /* length to copy */ | |
1458 | caddr_t data, /* data address */ | |
1459 | page_buf_rw_t mode) /* read/write flag */ | |
1460 | { | |
1461 | size_t bend, cpoff, csize; | |
1462 | struct page *page; | |
1463 | ||
1464 | bend = boff + bsize; | |
1465 | while (boff < bend) { | |
1466 | page = pb->pb_pages[page_buf_btoct(boff + pb->pb_offset)]; | |
1467 | cpoff = page_buf_poff(boff + pb->pb_offset); | |
1468 | csize = min_t(size_t, | |
1469 | PAGE_CACHE_SIZE-cpoff, pb->pb_count_desired-boff); | |
1470 | ||
1471 | ASSERT(((csize + cpoff) <= PAGE_CACHE_SIZE)); | |
1472 | ||
1473 | switch (mode) { | |
1474 | case PBRW_ZERO: | |
1475 | memset(page_address(page) + cpoff, 0, csize); | |
1476 | break; | |
1477 | case PBRW_READ: | |
1478 | memcpy(data, page_address(page) + cpoff, csize); | |
1479 | break; | |
1480 | case PBRW_WRITE: | |
1481 | memcpy(page_address(page) + cpoff, data, csize); | |
1482 | } | |
1483 | ||
1484 | boff += csize; | |
1485 | data += csize; | |
1486 | } | |
1487 | } | |
1488 | ||
1489 | /* | |
1490 | * Handling of buftargs. | |
1491 | */ | |
1492 | ||
1493 | /* | |
1494 | * Wait for any bufs with callbacks that have been submitted but | |
1495 | * have not yet returned... walk the hash list for the target. | |
1496 | */ | |
1497 | void | |
1498 | xfs_wait_buftarg( | |
1499 | xfs_buftarg_t *btp) | |
1500 | { | |
1501 | xfs_buf_t *bp, *n; | |
1502 | xfs_bufhash_t *hash; | |
1503 | uint i; | |
1504 | ||
1505 | for (i = 0; i < (1 << btp->bt_hashshift); i++) { | |
1506 | hash = &btp->bt_hash[i]; | |
1507 | again: | |
1508 | spin_lock(&hash->bh_lock); | |
1509 | list_for_each_entry_safe(bp, n, &hash->bh_list, pb_hash_list) { | |
1510 | ASSERT(btp == bp->pb_target); | |
1511 | if (!(bp->pb_flags & PBF_FS_MANAGED)) { | |
1512 | spin_unlock(&hash->bh_lock); | |
1513 | delay(100); | |
1514 | goto again; | |
1515 | } | |
1516 | } | |
1517 | spin_unlock(&hash->bh_lock); | |
1518 | } | |
1519 | } | |
1520 | ||
1521 | /* | |
1522 | * Allocate buffer hash table for a given target. | |
1523 | * For devices containing metadata (i.e. not the log/realtime devices) | |
1524 | * we need to allocate a much larger hash table. | |
1525 | */ | |
1526 | STATIC void | |
1527 | xfs_alloc_bufhash( | |
1528 | xfs_buftarg_t *btp, | |
1529 | int external) | |
1530 | { | |
1531 | unsigned int i; | |
1532 | ||
1533 | btp->bt_hashshift = external ? 3 : 8; /* 8 or 256 buckets */ | |
1534 | btp->bt_hashmask = (1 << btp->bt_hashshift) - 1; | |
1535 | btp->bt_hash = kmem_zalloc((1 << btp->bt_hashshift) * | |
1536 | sizeof(xfs_bufhash_t), KM_SLEEP); | |
1537 | for (i = 0; i < (1 << btp->bt_hashshift); i++) { | |
1538 | spin_lock_init(&btp->bt_hash[i].bh_lock); | |
1539 | INIT_LIST_HEAD(&btp->bt_hash[i].bh_list); | |
1540 | } | |
1541 | } | |
1542 | ||
1543 | STATIC void | |
1544 | xfs_free_bufhash( | |
1545 | xfs_buftarg_t *btp) | |
1546 | { | |
1547 | kmem_free(btp->bt_hash, | |
1548 | (1 << btp->bt_hashshift) * sizeof(xfs_bufhash_t)); | |
1549 | btp->bt_hash = NULL; | |
1550 | } | |
1551 | ||
1552 | void | |
1553 | xfs_free_buftarg( | |
1554 | xfs_buftarg_t *btp, | |
1555 | int external) | |
1556 | { | |
1557 | xfs_flush_buftarg(btp, 1); | |
1558 | if (external) | |
1559 | xfs_blkdev_put(btp->pbr_bdev); | |
1560 | xfs_free_bufhash(btp); | |
1561 | iput(btp->pbr_mapping->host); | |
1562 | kmem_free(btp, sizeof(*btp)); | |
1563 | } | |
1564 | ||
1565 | void | |
1566 | xfs_incore_relse( | |
1567 | xfs_buftarg_t *btp, | |
1568 | int delwri_only, | |
1569 | int wait) | |
1570 | { | |
1571 | invalidate_bdev(btp->pbr_bdev, 1); | |
1572 | truncate_inode_pages(btp->pbr_mapping, 0LL); | |
1573 | } | |
1574 | ||
1575 | STATIC int | |
1576 | xfs_setsize_buftarg_flags( | |
1577 | xfs_buftarg_t *btp, | |
1578 | unsigned int blocksize, | |
1579 | unsigned int sectorsize, | |
1580 | int verbose) | |
1581 | { | |
1582 | btp->pbr_bsize = blocksize; | |
1583 | btp->pbr_sshift = ffs(sectorsize) - 1; | |
1584 | btp->pbr_smask = sectorsize - 1; | |
1585 | ||
1586 | if (set_blocksize(btp->pbr_bdev, sectorsize)) { | |
1587 | printk(KERN_WARNING | |
1588 | "XFS: Cannot set_blocksize to %u on device %s\n", | |
1589 | sectorsize, XFS_BUFTARG_NAME(btp)); | |
1590 | return EINVAL; | |
1591 | } | |
1592 | ||
1593 | if (verbose && | |
1594 | (PAGE_CACHE_SIZE / BITS_PER_LONG) > sectorsize) { | |
1595 | printk(KERN_WARNING | |
1596 | "XFS: %u byte sectors in use on device %s. " | |
1597 | "This is suboptimal; %u or greater is ideal.\n", | |
1598 | sectorsize, XFS_BUFTARG_NAME(btp), | |
1599 | (unsigned int)PAGE_CACHE_SIZE / BITS_PER_LONG); | |
1600 | } | |
1601 | ||
1602 | return 0; | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * When allocating the initial buffer target we have not yet | |
1607 | * read in the superblock, so don't know what sized sectors | |
1608 | * are being used is at this early stage. Play safe. | |
1609 | */ | |
1610 | STATIC int | |
1611 | xfs_setsize_buftarg_early( | |
1612 | xfs_buftarg_t *btp, | |
1613 | struct block_device *bdev) | |
1614 | { | |
1615 | return xfs_setsize_buftarg_flags(btp, | |
1616 | PAGE_CACHE_SIZE, bdev_hardsect_size(bdev), 0); | |
1617 | } | |
1618 | ||
1619 | int | |
1620 | xfs_setsize_buftarg( | |
1621 | xfs_buftarg_t *btp, | |
1622 | unsigned int blocksize, | |
1623 | unsigned int sectorsize) | |
1624 | { | |
1625 | return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1); | |
1626 | } | |
1627 | ||
1628 | STATIC int | |
1629 | xfs_mapping_buftarg( | |
1630 | xfs_buftarg_t *btp, | |
1631 | struct block_device *bdev) | |
1632 | { | |
1633 | struct backing_dev_info *bdi; | |
1634 | struct inode *inode; | |
1635 | struct address_space *mapping; | |
1636 | static struct address_space_operations mapping_aops = { | |
1637 | .sync_page = block_sync_page, | |
1638 | }; | |
1639 | ||
1640 | inode = new_inode(bdev->bd_inode->i_sb); | |
1641 | if (!inode) { | |
1642 | printk(KERN_WARNING | |
1643 | "XFS: Cannot allocate mapping inode for device %s\n", | |
1644 | XFS_BUFTARG_NAME(btp)); | |
1645 | return ENOMEM; | |
1646 | } | |
1647 | inode->i_mode = S_IFBLK; | |
1648 | inode->i_bdev = bdev; | |
1649 | inode->i_rdev = bdev->bd_dev; | |
1650 | bdi = blk_get_backing_dev_info(bdev); | |
1651 | if (!bdi) | |
1652 | bdi = &default_backing_dev_info; | |
1653 | mapping = &inode->i_data; | |
1654 | mapping->a_ops = &mapping_aops; | |
1655 | mapping->backing_dev_info = bdi; | |
1656 | mapping_set_gfp_mask(mapping, GFP_NOFS); | |
1657 | btp->pbr_mapping = mapping; | |
1658 | return 0; | |
1659 | } | |
1660 | ||
1661 | xfs_buftarg_t * | |
1662 | xfs_alloc_buftarg( | |
1663 | struct block_device *bdev, | |
1664 | int external) | |
1665 | { | |
1666 | xfs_buftarg_t *btp; | |
1667 | ||
1668 | btp = kmem_zalloc(sizeof(*btp), KM_SLEEP); | |
1669 | ||
1670 | btp->pbr_dev = bdev->bd_dev; | |
1671 | btp->pbr_bdev = bdev; | |
1672 | if (xfs_setsize_buftarg_early(btp, bdev)) | |
1673 | goto error; | |
1674 | if (xfs_mapping_buftarg(btp, bdev)) | |
1675 | goto error; | |
1676 | xfs_alloc_bufhash(btp, external); | |
1677 | return btp; | |
1678 | ||
1679 | error: | |
1680 | kmem_free(btp, sizeof(*btp)); | |
1681 | return NULL; | |
1682 | } | |
1683 | ||
1684 | ||
1685 | /* | |
1686 | * Pagebuf delayed write buffer handling | |
1687 | */ | |
1688 | ||
1689 | STATIC LIST_HEAD(pbd_delwrite_queue); | |
1690 | STATIC DEFINE_SPINLOCK(pbd_delwrite_lock); | |
1691 | ||
1692 | STATIC void | |
1693 | pagebuf_delwri_queue( | |
1694 | xfs_buf_t *pb, | |
1695 | int unlock) | |
1696 | { | |
1697 | PB_TRACE(pb, "delwri_q", (long)unlock); | |
1698 | ASSERT(pb->pb_flags & PBF_DELWRI); | |
1699 | ||
1700 | spin_lock(&pbd_delwrite_lock); | |
1701 | /* If already in the queue, dequeue and place at tail */ | |
1702 | if (!list_empty(&pb->pb_list)) { | |
1703 | if (unlock) { | |
1704 | atomic_dec(&pb->pb_hold); | |
1705 | } | |
1706 | list_del(&pb->pb_list); | |
1707 | } | |
1708 | ||
1709 | list_add_tail(&pb->pb_list, &pbd_delwrite_queue); | |
1710 | pb->pb_queuetime = jiffies; | |
1711 | spin_unlock(&pbd_delwrite_lock); | |
1712 | ||
1713 | if (unlock) | |
1714 | pagebuf_unlock(pb); | |
1715 | } | |
1716 | ||
1717 | void | |
1718 | pagebuf_delwri_dequeue( | |
1719 | xfs_buf_t *pb) | |
1720 | { | |
1721 | int dequeued = 0; | |
1722 | ||
1723 | spin_lock(&pbd_delwrite_lock); | |
1724 | if ((pb->pb_flags & PBF_DELWRI) && !list_empty(&pb->pb_list)) { | |
1725 | list_del_init(&pb->pb_list); | |
1726 | dequeued = 1; | |
1727 | } | |
1728 | pb->pb_flags &= ~PBF_DELWRI; | |
1729 | spin_unlock(&pbd_delwrite_lock); | |
1730 | ||
1731 | if (dequeued) | |
1732 | pagebuf_rele(pb); | |
1733 | ||
1734 | PB_TRACE(pb, "delwri_dq", (long)dequeued); | |
1735 | } | |
1736 | ||
1737 | STATIC void | |
1738 | pagebuf_runall_queues( | |
1739 | struct workqueue_struct *queue) | |
1740 | { | |
1741 | flush_workqueue(queue); | |
1742 | } | |
1743 | ||
1744 | /* Defines for pagebuf daemon */ | |
1745 | STATIC DECLARE_COMPLETION(pagebuf_daemon_done); | |
1746 | STATIC struct task_struct *pagebuf_daemon_task; | |
1747 | STATIC int pagebuf_daemon_active; | |
1748 | STATIC int force_flush; | |
abd0cf7a | 1749 | STATIC int force_sleep; |
1da177e4 LT |
1750 | |
1751 | STATIC int | |
1752 | pagebuf_daemon_wakeup( | |
1753 | int priority, | |
1754 | unsigned int mask) | |
1755 | { | |
abd0cf7a NS |
1756 | if (force_sleep) |
1757 | return 0; | |
1da177e4 LT |
1758 | force_flush = 1; |
1759 | barrier(); | |
1760 | wake_up_process(pagebuf_daemon_task); | |
1761 | return 0; | |
1762 | } | |
1763 | ||
1764 | STATIC int | |
1765 | pagebuf_daemon( | |
1766 | void *data) | |
1767 | { | |
1768 | struct list_head tmp; | |
1769 | unsigned long age; | |
1770 | xfs_buftarg_t *target; | |
1771 | xfs_buf_t *pb, *n; | |
1772 | ||
1773 | /* Set up the thread */ | |
1774 | daemonize("xfsbufd"); | |
1775 | current->flags |= PF_MEMALLOC; | |
1776 | ||
1777 | pagebuf_daemon_task = current; | |
1778 | pagebuf_daemon_active = 1; | |
1779 | barrier(); | |
1780 | ||
1781 | INIT_LIST_HEAD(&tmp); | |
1782 | do { | |
abd0cf7a NS |
1783 | if (unlikely(current->flags & PF_FREEZE)) { |
1784 | force_sleep = 1; | |
1785 | refrigerator(PF_FREEZE); | |
1786 | } else { | |
1787 | force_sleep = 0; | |
1788 | } | |
1da177e4 LT |
1789 | |
1790 | set_current_state(TASK_INTERRUPTIBLE); | |
1791 | schedule_timeout((xfs_buf_timer_centisecs * HZ) / 100); | |
1792 | ||
1793 | age = (xfs_buf_age_centisecs * HZ) / 100; | |
1794 | spin_lock(&pbd_delwrite_lock); | |
1795 | list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) { | |
1796 | PB_TRACE(pb, "walkq1", (long)pagebuf_ispin(pb)); | |
1797 | ASSERT(pb->pb_flags & PBF_DELWRI); | |
1798 | ||
1799 | if (!pagebuf_ispin(pb) && !pagebuf_cond_lock(pb)) { | |
1800 | if (!force_flush && | |
1801 | time_before(jiffies, | |
1802 | pb->pb_queuetime + age)) { | |
1803 | pagebuf_unlock(pb); | |
1804 | break; | |
1805 | } | |
1806 | ||
1807 | pb->pb_flags &= ~PBF_DELWRI; | |
1808 | pb->pb_flags |= PBF_WRITE; | |
1809 | list_move(&pb->pb_list, &tmp); | |
1810 | } | |
1811 | } | |
1812 | spin_unlock(&pbd_delwrite_lock); | |
1813 | ||
1814 | while (!list_empty(&tmp)) { | |
1815 | pb = list_entry(tmp.next, xfs_buf_t, pb_list); | |
1816 | target = pb->pb_target; | |
1817 | ||
1818 | list_del_init(&pb->pb_list); | |
1819 | pagebuf_iostrategy(pb); | |
1820 | ||
1821 | blk_run_address_space(target->pbr_mapping); | |
1822 | } | |
1823 | ||
1824 | if (as_list_len > 0) | |
1825 | purge_addresses(); | |
1826 | ||
1827 | force_flush = 0; | |
1828 | } while (pagebuf_daemon_active); | |
1829 | ||
1830 | complete_and_exit(&pagebuf_daemon_done, 0); | |
1831 | } | |
1832 | ||
1833 | /* | |
1834 | * Go through all incore buffers, and release buffers if they belong to | |
1835 | * the given device. This is used in filesystem error handling to | |
1836 | * preserve the consistency of its metadata. | |
1837 | */ | |
1838 | int | |
1839 | xfs_flush_buftarg( | |
1840 | xfs_buftarg_t *target, | |
1841 | int wait) | |
1842 | { | |
1843 | struct list_head tmp; | |
1844 | xfs_buf_t *pb, *n; | |
1845 | int pincount = 0; | |
1846 | ||
1847 | pagebuf_runall_queues(pagebuf_dataio_workqueue); | |
1848 | pagebuf_runall_queues(pagebuf_logio_workqueue); | |
1849 | ||
1850 | INIT_LIST_HEAD(&tmp); | |
1851 | spin_lock(&pbd_delwrite_lock); | |
1852 | list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) { | |
1853 | ||
1854 | if (pb->pb_target != target) | |
1855 | continue; | |
1856 | ||
1857 | ASSERT(pb->pb_flags & PBF_DELWRI); | |
1858 | PB_TRACE(pb, "walkq2", (long)pagebuf_ispin(pb)); | |
1859 | if (pagebuf_ispin(pb)) { | |
1860 | pincount++; | |
1861 | continue; | |
1862 | } | |
1863 | ||
1864 | pb->pb_flags &= ~PBF_DELWRI; | |
1865 | pb->pb_flags |= PBF_WRITE; | |
1866 | list_move(&pb->pb_list, &tmp); | |
1867 | } | |
1868 | spin_unlock(&pbd_delwrite_lock); | |
1869 | ||
1870 | /* | |
1871 | * Dropped the delayed write list lock, now walk the temporary list | |
1872 | */ | |
1873 | list_for_each_entry_safe(pb, n, &tmp, pb_list) { | |
1874 | if (wait) | |
1875 | pb->pb_flags &= ~PBF_ASYNC; | |
1876 | else | |
1877 | list_del_init(&pb->pb_list); | |
1878 | ||
1879 | pagebuf_lock(pb); | |
1880 | pagebuf_iostrategy(pb); | |
1881 | } | |
1882 | ||
1883 | /* | |
1884 | * Remaining list items must be flushed before returning | |
1885 | */ | |
1886 | while (!list_empty(&tmp)) { | |
1887 | pb = list_entry(tmp.next, xfs_buf_t, pb_list); | |
1888 | ||
1889 | list_del_init(&pb->pb_list); | |
1890 | xfs_iowait(pb); | |
1891 | xfs_buf_relse(pb); | |
1892 | } | |
1893 | ||
1894 | if (wait) | |
1895 | blk_run_address_space(target->pbr_mapping); | |
1896 | ||
1897 | return pincount; | |
1898 | } | |
1899 | ||
1900 | STATIC int | |
1901 | pagebuf_daemon_start(void) | |
1902 | { | |
1903 | int rval; | |
1904 | ||
1905 | pagebuf_logio_workqueue = create_workqueue("xfslogd"); | |
1906 | if (!pagebuf_logio_workqueue) | |
1907 | return -ENOMEM; | |
1908 | ||
1909 | pagebuf_dataio_workqueue = create_workqueue("xfsdatad"); | |
1910 | if (!pagebuf_dataio_workqueue) { | |
1911 | destroy_workqueue(pagebuf_logio_workqueue); | |
1912 | return -ENOMEM; | |
1913 | } | |
1914 | ||
1915 | rval = kernel_thread(pagebuf_daemon, NULL, CLONE_FS|CLONE_FILES); | |
1916 | if (rval < 0) { | |
1917 | destroy_workqueue(pagebuf_logio_workqueue); | |
1918 | destroy_workqueue(pagebuf_dataio_workqueue); | |
1919 | } | |
1920 | ||
1921 | return rval; | |
1922 | } | |
1923 | ||
1924 | /* | |
1925 | * pagebuf_daemon_stop | |
1926 | * | |
1927 | * Note: do not mark as __exit, it is called from pagebuf_terminate. | |
1928 | */ | |
1929 | STATIC void | |
1930 | pagebuf_daemon_stop(void) | |
1931 | { | |
1932 | pagebuf_daemon_active = 0; | |
1933 | barrier(); | |
1934 | wait_for_completion(&pagebuf_daemon_done); | |
1935 | ||
1936 | destroy_workqueue(pagebuf_logio_workqueue); | |
1937 | destroy_workqueue(pagebuf_dataio_workqueue); | |
1938 | } | |
1939 | ||
1940 | /* | |
1941 | * Initialization and Termination | |
1942 | */ | |
1943 | ||
1944 | int __init | |
1945 | pagebuf_init(void) | |
1946 | { | |
1947 | pagebuf_cache = kmem_cache_create("xfs_buf_t", sizeof(xfs_buf_t), 0, | |
1948 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1949 | if (pagebuf_cache == NULL) { | |
1950 | printk("XFS: couldn't init xfs_buf_t cache\n"); | |
1951 | pagebuf_terminate(); | |
1952 | return -ENOMEM; | |
1953 | } | |
1954 | ||
1955 | #ifdef PAGEBUF_TRACE | |
1956 | pagebuf_trace_buf = ktrace_alloc(PAGEBUF_TRACE_SIZE, KM_SLEEP); | |
1957 | #endif | |
1958 | ||
1959 | pagebuf_daemon_start(); | |
1960 | ||
1961 | pagebuf_shake = kmem_shake_register(pagebuf_daemon_wakeup); | |
1962 | if (pagebuf_shake == NULL) { | |
1963 | pagebuf_terminate(); | |
1964 | return -ENOMEM; | |
1965 | } | |
1966 | ||
1967 | return 0; | |
1968 | } | |
1969 | ||
1970 | ||
1971 | /* | |
1972 | * pagebuf_terminate. | |
1973 | * | |
1974 | * Note: do not mark as __exit, this is also called from the __init code. | |
1975 | */ | |
1976 | void | |
1977 | pagebuf_terminate(void) | |
1978 | { | |
1979 | pagebuf_daemon_stop(); | |
1980 | ||
1981 | #ifdef PAGEBUF_TRACE | |
1982 | ktrace_free(pagebuf_trace_buf); | |
1983 | #endif | |
1984 | ||
1985 | kmem_zone_destroy(pagebuf_cache); | |
1986 | kmem_shake_deregister(pagebuf_shake); | |
1987 | } |