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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/xfs/linux-2.6/xfs_buf.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/xfs/linux-2.6/xfs_buf.c')
-rw-r--r--fs/xfs/linux-2.6/xfs_buf.c1980
1 files changed, 1980 insertions, 0 deletions
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
new file mode 100644
index 000000000000..23e0eb67fc25
--- /dev/null
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -0,0 +1,1980 @@
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
64STATIC kmem_cache_t *pagebuf_cache;
65STATIC kmem_shaker_t pagebuf_shake;
66STATIC int pagebuf_daemon_wakeup(int, unsigned int);
67STATIC void pagebuf_delwri_queue(xfs_buf_t *, int);
68STATIC struct workqueue_struct *pagebuf_logio_workqueue;
69STATIC struct workqueue_struct *pagebuf_dataio_workqueue;
70
71/*
72 * Pagebuf debugging
73 */
74
75#ifdef PAGEBUF_TRACE
76void
77pagebuf_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}
95ktrace_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
154STATIC unsigned long
155page_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
176STATIC inline void
177set_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
187STATIC inline int
188test_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
202typedef struct a_list {
203 void *vm_addr;
204 struct a_list *next;
205} a_list_t;
206
207STATIC a_list_t *as_free_head;
208STATIC int as_list_len;
209STATIC DEFINE_SPINLOCK(as_lock);
210
211/*
212 * Try to batch vunmaps because they are costly.
213 */
214STATIC void
215free_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
233STATIC void
234purge_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
258STATIC 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 */
299STATIC 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 */
325STATIC 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 */
342void
343pagebuf_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 */
375STATIC 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 */
474STATIC 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 */
511xfs_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
562found:
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 */
605xfs_buf_t *
606xfs_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
661xfs_buf_t *
662xfs_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 */
704xfs_buf_t *
705pagebuf_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 */
724void
725pagebuf_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
741xfs_buf_t *
742pagebuf_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
754static inline struct page *
755mem_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
766int
767pagebuf_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
817xfs_buf_t *
818pagebuf_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 */
871void
872pagebuf_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 */
885void
886pagebuf_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 */
954int
955pagebuf_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 */
975int
976pagebuf_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 */
991int
992pagebuf_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 */
1011void
1012pagebuf_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 */
1039void
1040pagebuf_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 */
1054void
1055pagebuf_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
1064int
1065pagebuf_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 */
1078static 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 */
1111STATIC void
1112pagebuf_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
1123void
1124pagebuf_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 */
1154void
1155pagebuf_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 */
1176int
1177pagebuf_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
1223STATIC __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
1233STATIC __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
1244STATIC int
1245bio_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
1282STATIC 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
1345next_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
1373submit_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 */
1387int
1388pagebuf_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 */
1423int
1424pagebuf_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
1435caddr_t
1436pagebuf_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 */
1453void
1454pagebuf_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 */
1497void
1498xfs_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];
1507again:
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 */
1526STATIC void
1527xfs_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
1543STATIC void
1544xfs_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
1552void
1553xfs_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
1565void
1566xfs_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
1575STATIC int
1576xfs_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*/
1610STATIC int
1611xfs_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
1619int
1620xfs_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
1628STATIC int
1629xfs_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
1661xfs_buftarg_t *
1662xfs_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
1679error:
1680 kmem_free(btp, sizeof(*btp));
1681 return NULL;
1682}
1683
1684
1685/*
1686 * Pagebuf delayed write buffer handling
1687 */
1688
1689STATIC LIST_HEAD(pbd_delwrite_queue);
1690STATIC DEFINE_SPINLOCK(pbd_delwrite_lock);
1691
1692STATIC void
1693pagebuf_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
1717void
1718pagebuf_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
1737STATIC void
1738pagebuf_runall_queues(
1739 struct workqueue_struct *queue)
1740{
1741 flush_workqueue(queue);
1742}
1743
1744/* Defines for pagebuf daemon */
1745STATIC DECLARE_COMPLETION(pagebuf_daemon_done);
1746STATIC struct task_struct *pagebuf_daemon_task;
1747STATIC int pagebuf_daemon_active;
1748STATIC int force_flush;
1749
1750
1751STATIC int
1752pagebuf_daemon_wakeup(
1753 int priority,
1754 unsigned int mask)
1755{
1756 force_flush = 1;
1757 barrier();
1758 wake_up_process(pagebuf_daemon_task);
1759 return 0;
1760}
1761
1762STATIC int
1763pagebuf_daemon(
1764 void *data)
1765{
1766 struct list_head tmp;
1767 unsigned long age;
1768 xfs_buftarg_t *target;
1769 xfs_buf_t *pb, *n;
1770
1771 /* Set up the thread */
1772 daemonize("xfsbufd");
1773 current->flags |= PF_MEMALLOC;
1774
1775 pagebuf_daemon_task = current;
1776 pagebuf_daemon_active = 1;
1777 barrier();
1778
1779 INIT_LIST_HEAD(&tmp);
1780 do {
1781 try_to_freeze(PF_FREEZE);
1782
1783 set_current_state(TASK_INTERRUPTIBLE);
1784 schedule_timeout((xfs_buf_timer_centisecs * HZ) / 100);
1785
1786 age = (xfs_buf_age_centisecs * HZ) / 100;
1787 spin_lock(&pbd_delwrite_lock);
1788 list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) {
1789 PB_TRACE(pb, "walkq1", (long)pagebuf_ispin(pb));
1790 ASSERT(pb->pb_flags & PBF_DELWRI);
1791
1792 if (!pagebuf_ispin(pb) && !pagebuf_cond_lock(pb)) {
1793 if (!force_flush &&
1794 time_before(jiffies,
1795 pb->pb_queuetime + age)) {
1796 pagebuf_unlock(pb);
1797 break;
1798 }
1799
1800 pb->pb_flags &= ~PBF_DELWRI;
1801 pb->pb_flags |= PBF_WRITE;
1802 list_move(&pb->pb_list, &tmp);
1803 }
1804 }
1805 spin_unlock(&pbd_delwrite_lock);
1806
1807 while (!list_empty(&tmp)) {
1808 pb = list_entry(tmp.next, xfs_buf_t, pb_list);
1809 target = pb->pb_target;
1810
1811 list_del_init(&pb->pb_list);
1812 pagebuf_iostrategy(pb);
1813
1814 blk_run_address_space(target->pbr_mapping);
1815 }
1816
1817 if (as_list_len > 0)
1818 purge_addresses();
1819
1820 force_flush = 0;
1821 } while (pagebuf_daemon_active);
1822
1823 complete_and_exit(&pagebuf_daemon_done, 0);
1824}
1825
1826/*
1827 * Go through all incore buffers, and release buffers if they belong to
1828 * the given device. This is used in filesystem error handling to
1829 * preserve the consistency of its metadata.
1830 */
1831int
1832xfs_flush_buftarg(
1833 xfs_buftarg_t *target,
1834 int wait)
1835{
1836 struct list_head tmp;
1837 xfs_buf_t *pb, *n;
1838 int pincount = 0;
1839
1840 pagebuf_runall_queues(pagebuf_dataio_workqueue);
1841 pagebuf_runall_queues(pagebuf_logio_workqueue);
1842
1843 INIT_LIST_HEAD(&tmp);
1844 spin_lock(&pbd_delwrite_lock);
1845 list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) {
1846
1847 if (pb->pb_target != target)
1848 continue;
1849
1850 ASSERT(pb->pb_flags & PBF_DELWRI);
1851 PB_TRACE(pb, "walkq2", (long)pagebuf_ispin(pb));
1852 if (pagebuf_ispin(pb)) {
1853 pincount++;
1854 continue;
1855 }
1856
1857 pb->pb_flags &= ~PBF_DELWRI;
1858 pb->pb_flags |= PBF_WRITE;
1859 list_move(&pb->pb_list, &tmp);
1860 }
1861 spin_unlock(&pbd_delwrite_lock);
1862
1863 /*
1864 * Dropped the delayed write list lock, now walk the temporary list
1865 */
1866 list_for_each_entry_safe(pb, n, &tmp, pb_list) {
1867 if (wait)
1868 pb->pb_flags &= ~PBF_ASYNC;
1869 else
1870 list_del_init(&pb->pb_list);
1871
1872 pagebuf_lock(pb);
1873 pagebuf_iostrategy(pb);
1874 }
1875
1876 /*
1877 * Remaining list items must be flushed before returning
1878 */
1879 while (!list_empty(&tmp)) {
1880 pb = list_entry(tmp.next, xfs_buf_t, pb_list);
1881
1882 list_del_init(&pb->pb_list);
1883 xfs_iowait(pb);
1884 xfs_buf_relse(pb);
1885 }
1886
1887 if (wait)
1888 blk_run_address_space(target->pbr_mapping);
1889
1890 return pincount;
1891}
1892
1893STATIC int
1894pagebuf_daemon_start(void)
1895{
1896 int rval;
1897
1898 pagebuf_logio_workqueue = create_workqueue("xfslogd");
1899 if (!pagebuf_logio_workqueue)
1900 return -ENOMEM;
1901
1902 pagebuf_dataio_workqueue = create_workqueue("xfsdatad");
1903 if (!pagebuf_dataio_workqueue) {
1904 destroy_workqueue(pagebuf_logio_workqueue);
1905 return -ENOMEM;
1906 }
1907
1908 rval = kernel_thread(pagebuf_daemon, NULL, CLONE_FS|CLONE_FILES);
1909 if (rval < 0) {
1910 destroy_workqueue(pagebuf_logio_workqueue);
1911 destroy_workqueue(pagebuf_dataio_workqueue);
1912 }
1913
1914 return rval;
1915}
1916
1917/*
1918 * pagebuf_daemon_stop
1919 *
1920 * Note: do not mark as __exit, it is called from pagebuf_terminate.
1921 */
1922STATIC void
1923pagebuf_daemon_stop(void)
1924{
1925 pagebuf_daemon_active = 0;
1926 barrier();
1927 wait_for_completion(&pagebuf_daemon_done);
1928
1929 destroy_workqueue(pagebuf_logio_workqueue);
1930 destroy_workqueue(pagebuf_dataio_workqueue);
1931}
1932
1933/*
1934 * Initialization and Termination
1935 */
1936
1937int __init
1938pagebuf_init(void)
1939{
1940 pagebuf_cache = kmem_cache_create("xfs_buf_t", sizeof(xfs_buf_t), 0,
1941 SLAB_HWCACHE_ALIGN, NULL, NULL);
1942 if (pagebuf_cache == NULL) {
1943 printk("XFS: couldn't init xfs_buf_t cache\n");
1944 pagebuf_terminate();
1945 return -ENOMEM;
1946 }
1947
1948#ifdef PAGEBUF_TRACE
1949 pagebuf_trace_buf = ktrace_alloc(PAGEBUF_TRACE_SIZE, KM_SLEEP);
1950#endif
1951
1952 pagebuf_daemon_start();
1953
1954 pagebuf_shake = kmem_shake_register(pagebuf_daemon_wakeup);
1955 if (pagebuf_shake == NULL) {
1956 pagebuf_terminate();
1957 return -ENOMEM;
1958 }
1959
1960 return 0;
1961}
1962
1963
1964/*
1965 * pagebuf_terminate.
1966 *
1967 * Note: do not mark as __exit, this is also called from the __init code.
1968 */
1969void
1970pagebuf_terminate(void)
1971{
1972 pagebuf_daemon_stop();
1973
1974#ifdef PAGEBUF_TRACE
1975 ktrace_free(pagebuf_trace_buf);
1976#endif
1977
1978 kmem_zone_destroy(pagebuf_cache);
1979 kmem_shake_deregister(pagebuf_shake);
1980}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-05 07:25:06 -0500