2 * Copyright (c) 2000-2005 Silicon Graphics, Inc. All Rights Reserved.
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.
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.
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.
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.
23 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
24 * Mountain View, CA 94043, or:
28 * For further information regarding this notice, see:
30 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
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.
39 * Written by Steve Lord, Jim Mostek, Russell Cattelan
40 * and Rajagopal Ananthanarayanan ("ananth") at SGI.
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 #include <linux/kthread.h>
59 #include "xfs_linux.h"
65 STATIC kmem_cache_t
*pagebuf_zone
;
66 STATIC kmem_shaker_t pagebuf_shake
;
67 STATIC
int xfsbufd_wakeup(int, gfp_t
);
68 STATIC
void pagebuf_delwri_queue(xfs_buf_t
*, int);
70 STATIC
struct workqueue_struct
*xfslogd_workqueue
;
71 struct workqueue_struct
*xfsdatad_workqueue
;
85 ktrace_enter(pagebuf_trace_buf
,
87 (void *)(unsigned long)pb
->pb_flags
,
88 (void *)(unsigned long)pb
->pb_hold
.counter
,
89 (void *)(unsigned long)pb
->pb_sema
.count
.counter
,
92 (void *)(unsigned long)((pb
->pb_file_offset
>>32) & 0xffffffff),
93 (void *)(unsigned long)(pb
->pb_file_offset
& 0xffffffff),
94 (void *)(unsigned long)pb
->pb_buffer_length
,
95 NULL
, NULL
, NULL
, NULL
, NULL
);
97 ktrace_t
*pagebuf_trace_buf
;
98 #define PAGEBUF_TRACE_SIZE 4096
99 #define PB_TRACE(pb, id, data) \
100 pagebuf_trace(pb, id, (void *)data, (void *)__builtin_return_address(0))
102 #define PB_TRACE(pb, id, data) do { } while (0)
105 #ifdef PAGEBUF_LOCK_TRACKING
106 # define PB_SET_OWNER(pb) ((pb)->pb_last_holder = current->pid)
107 # define PB_CLEAR_OWNER(pb) ((pb)->pb_last_holder = -1)
108 # define PB_GET_OWNER(pb) ((pb)->pb_last_holder)
110 # define PB_SET_OWNER(pb) do { } while (0)
111 # define PB_CLEAR_OWNER(pb) do { } while (0)
112 # define PB_GET_OWNER(pb) do { } while (0)
116 * Pagebuf allocation / freeing.
119 #define pb_to_gfp(flags) \
120 ((((flags) & PBF_READ_AHEAD) ? __GFP_NORETRY : \
121 ((flags) & PBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN)
123 #define pb_to_km(flags) \
124 (((flags) & PBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)
127 #define pagebuf_allocate(flags) \
128 kmem_zone_alloc(pagebuf_zone, pb_to_km(flags))
129 #define pagebuf_deallocate(pb) \
130 kmem_zone_free(pagebuf_zone, (pb));
133 * Page Region interfaces.
135 * For pages in filesystems where the blocksize is smaller than the
136 * pagesize, we use the page->private field (long) to hold a bitmap
137 * of uptodate regions within the page.
139 * Each such region is "bytes per page / bits per long" bytes long.
141 * NBPPR == number-of-bytes-per-page-region
142 * BTOPR == bytes-to-page-region (rounded up)
143 * BTOPRT == bytes-to-page-region-truncated (rounded down)
145 #if (BITS_PER_LONG == 32)
146 #define PRSHIFT (PAGE_CACHE_SHIFT - 5) /* (32 == 1<<5) */
147 #elif (BITS_PER_LONG == 64)
148 #define PRSHIFT (PAGE_CACHE_SHIFT - 6) /* (64 == 1<<6) */
150 #error BITS_PER_LONG must be 32 or 64
152 #define NBPPR (PAGE_CACHE_SIZE/BITS_PER_LONG)
153 #define BTOPR(b) (((unsigned int)(b) + (NBPPR - 1)) >> PRSHIFT)
154 #define BTOPRT(b) (((unsigned int)(b) >> PRSHIFT))
164 first
= BTOPR(offset
);
165 final
= BTOPRT(offset
+ length
- 1);
166 first
= min(first
, final
);
169 mask
<<= BITS_PER_LONG
- (final
- first
);
170 mask
>>= BITS_PER_LONG
- (final
);
172 ASSERT(offset
+ length
<= PAGE_CACHE_SIZE
);
173 ASSERT((final
- first
) < BITS_PER_LONG
&& (final
- first
) >= 0);
184 set_page_private(page
,
185 page_private(page
) | page_region_mask(offset
, length
));
186 if (page_private(page
) == ~0UL)
187 SetPageUptodate(page
);
196 unsigned long mask
= page_region_mask(offset
, length
);
198 return (mask
&& (page_private(page
) & mask
) == mask
);
202 * Mapping of multi-page buffers into contiguous virtual space
205 typedef struct a_list
{
210 STATIC a_list_t
*as_free_head
;
211 STATIC
int as_list_len
;
212 STATIC
DEFINE_SPINLOCK(as_lock
);
215 * Try to batch vunmaps because they are costly.
223 aentry
= kmalloc(sizeof(a_list_t
), GFP_ATOMIC
& ~__GFP_HIGH
);
224 if (likely(aentry
)) {
226 aentry
->next
= as_free_head
;
227 aentry
->vm_addr
= addr
;
228 as_free_head
= aentry
;
230 spin_unlock(&as_lock
);
237 purge_addresses(void)
239 a_list_t
*aentry
, *old
;
241 if (as_free_head
== NULL
)
245 aentry
= as_free_head
;
248 spin_unlock(&as_lock
);
250 while ((old
= aentry
) != NULL
) {
251 vunmap(aentry
->vm_addr
);
252 aentry
= aentry
->next
;
258 * Internal pagebuf object manipulation
264 xfs_buftarg_t
*target
,
267 page_buf_flags_t flags
)
270 * We don't want certain flags to appear in pb->pb_flags.
272 flags
&= ~(PBF_LOCK
|PBF_MAPPED
|PBF_DONT_BLOCK
|PBF_READ_AHEAD
);
274 memset(pb
, 0, sizeof(xfs_buf_t
));
275 atomic_set(&pb
->pb_hold
, 1);
276 init_MUTEX_LOCKED(&pb
->pb_iodonesema
);
277 INIT_LIST_HEAD(&pb
->pb_list
);
278 INIT_LIST_HEAD(&pb
->pb_hash_list
);
279 init_MUTEX_LOCKED(&pb
->pb_sema
); /* held, no waiters */
281 pb
->pb_target
= target
;
282 pb
->pb_file_offset
= range_base
;
284 * Set buffer_length and count_desired to the same value initially.
285 * I/O routines should use count_desired, which will be the same in
286 * most cases but may be reset (e.g. XFS recovery).
288 pb
->pb_buffer_length
= pb
->pb_count_desired
= range_length
;
289 pb
->pb_flags
= flags
| PBF_NONE
;
290 pb
->pb_bn
= XFS_BUF_DADDR_NULL
;
291 atomic_set(&pb
->pb_pin_count
, 0);
292 init_waitqueue_head(&pb
->pb_waiters
);
294 XFS_STATS_INC(pb_create
);
295 PB_TRACE(pb
, "initialize", target
);
299 * Allocate a page array capable of holding a specified number
300 * of pages, and point the page buf at it.
306 page_buf_flags_t flags
)
308 /* Make sure that we have a page list */
309 if (pb
->pb_pages
== NULL
) {
310 pb
->pb_offset
= page_buf_poff(pb
->pb_file_offset
);
311 pb
->pb_page_count
= page_count
;
312 if (page_count
<= PB_PAGES
) {
313 pb
->pb_pages
= pb
->pb_page_array
;
315 pb
->pb_pages
= kmem_alloc(sizeof(struct page
*) *
316 page_count
, pb_to_km(flags
));
317 if (pb
->pb_pages
== NULL
)
320 memset(pb
->pb_pages
, 0, sizeof(struct page
*) * page_count
);
326 * Frees pb_pages if it was malloced.
332 if (bp
->pb_pages
!= bp
->pb_page_array
) {
333 kmem_free(bp
->pb_pages
,
334 bp
->pb_page_count
* sizeof(struct page
*));
339 * Releases the specified buffer.
341 * The modification state of any associated pages is left unchanged.
342 * The buffer most not be on any hash - use pagebuf_rele instead for
343 * hashed and refcounted buffers
349 PB_TRACE(bp
, "free", 0);
351 ASSERT(list_empty(&bp
->pb_hash_list
));
353 if (bp
->pb_flags
& _PBF_PAGE_CACHE
) {
356 if ((bp
->pb_flags
& PBF_MAPPED
) && (bp
->pb_page_count
> 1))
357 free_address(bp
->pb_addr
- bp
->pb_offset
);
359 for (i
= 0; i
< bp
->pb_page_count
; i
++)
360 page_cache_release(bp
->pb_pages
[i
]);
361 _pagebuf_free_pages(bp
);
362 } else if (bp
->pb_flags
& _PBF_KMEM_ALLOC
) {
364 * XXX(hch): bp->pb_count_desired might be incorrect (see
365 * pagebuf_associate_memory for details), but fortunately
366 * the Linux version of kmem_free ignores the len argument..
368 kmem_free(bp
->pb_addr
, bp
->pb_count_desired
);
369 _pagebuf_free_pages(bp
);
372 pagebuf_deallocate(bp
);
376 * Finds all pages for buffer in question and builds it's page list.
379 _pagebuf_lookup_pages(
383 struct address_space
*mapping
= bp
->pb_target
->pbr_mapping
;
384 size_t blocksize
= bp
->pb_target
->pbr_bsize
;
385 size_t size
= bp
->pb_count_desired
;
386 size_t nbytes
, offset
;
387 gfp_t gfp_mask
= pb_to_gfp(flags
);
388 unsigned short page_count
, i
;
393 end
= bp
->pb_file_offset
+ bp
->pb_buffer_length
;
394 page_count
= page_buf_btoc(end
) - page_buf_btoct(bp
->pb_file_offset
);
396 error
= _pagebuf_get_pages(bp
, page_count
, flags
);
399 bp
->pb_flags
|= _PBF_PAGE_CACHE
;
401 offset
= bp
->pb_offset
;
402 first
= bp
->pb_file_offset
>> PAGE_CACHE_SHIFT
;
404 for (i
= 0; i
< bp
->pb_page_count
; i
++) {
409 page
= find_or_create_page(mapping
, first
+ i
, gfp_mask
);
410 if (unlikely(page
== NULL
)) {
411 if (flags
& PBF_READ_AHEAD
) {
412 bp
->pb_page_count
= i
;
413 for (i
= 0; i
< bp
->pb_page_count
; i
++)
414 unlock_page(bp
->pb_pages
[i
]);
419 * This could deadlock.
421 * But until all the XFS lowlevel code is revamped to
422 * handle buffer allocation failures we can't do much.
424 if (!(++retries
% 100))
426 "XFS: possible memory allocation "
427 "deadlock in %s (mode:0x%x)\n",
428 __FUNCTION__
, gfp_mask
);
430 XFS_STATS_INC(pb_page_retries
);
431 xfsbufd_wakeup(0, gfp_mask
);
432 blk_congestion_wait(WRITE
, HZ
/50);
436 XFS_STATS_INC(pb_page_found
);
438 nbytes
= min_t(size_t, size
, PAGE_CACHE_SIZE
- offset
);
441 if (!PageUptodate(page
)) {
443 if (blocksize
>= PAGE_CACHE_SIZE
) {
444 if (flags
& PBF_READ
)
446 } else if (!PagePrivate(page
)) {
447 if (test_page_region(page
, offset
, nbytes
))
452 bp
->pb_pages
[i
] = page
;
456 if (!bp
->pb_locked
) {
457 for (i
= 0; i
< bp
->pb_page_count
; i
++)
458 unlock_page(bp
->pb_pages
[i
]);
462 bp
->pb_flags
&= ~PBF_NONE
;
464 PB_TRACE(bp
, "lookup_pages", (long)page_count
);
469 * Map buffer into kernel address-space if nessecary.
476 /* A single page buffer is always mappable */
477 if (bp
->pb_page_count
== 1) {
478 bp
->pb_addr
= page_address(bp
->pb_pages
[0]) + bp
->pb_offset
;
479 bp
->pb_flags
|= PBF_MAPPED
;
480 } else if (flags
& PBF_MAPPED
) {
481 if (as_list_len
> 64)
483 bp
->pb_addr
= vmap(bp
->pb_pages
, bp
->pb_page_count
,
484 VM_MAP
, PAGE_KERNEL
);
485 if (unlikely(bp
->pb_addr
== NULL
))
487 bp
->pb_addr
+= bp
->pb_offset
;
488 bp
->pb_flags
|= PBF_MAPPED
;
495 * Finding and Reading Buffers
501 * Looks up, and creates if absent, a lockable buffer for
502 * a given range of an inode. The buffer is returned
503 * locked. If other overlapping buffers exist, they are
504 * released before the new buffer is created and locked,
505 * which may imply that this call will block until those buffers
506 * are unlocked. No I/O is implied by this call.
510 xfs_buftarg_t
*btp
, /* block device target */
511 loff_t ioff
, /* starting offset of range */
512 size_t isize
, /* length of range */
513 page_buf_flags_t flags
, /* PBF_TRYLOCK */
514 xfs_buf_t
*new_pb
)/* newly allocated buffer */
521 range_base
= (ioff
<< BBSHIFT
);
522 range_length
= (isize
<< BBSHIFT
);
524 /* Check for IOs smaller than the sector size / not sector aligned */
525 ASSERT(!(range_length
< (1 << btp
->pbr_sshift
)));
526 ASSERT(!(range_base
& (loff_t
)btp
->pbr_smask
));
528 hash
= &btp
->bt_hash
[hash_long((unsigned long)ioff
, btp
->bt_hashshift
)];
530 spin_lock(&hash
->bh_lock
);
532 list_for_each_entry_safe(pb
, n
, &hash
->bh_list
, pb_hash_list
) {
533 ASSERT(btp
== pb
->pb_target
);
534 if (pb
->pb_file_offset
== range_base
&&
535 pb
->pb_buffer_length
== range_length
) {
537 * If we look at something bring it to the
538 * front of the list for next time.
540 atomic_inc(&pb
->pb_hold
);
541 list_move(&pb
->pb_hash_list
, &hash
->bh_list
);
548 _pagebuf_initialize(new_pb
, btp
, range_base
,
549 range_length
, flags
);
550 new_pb
->pb_hash
= hash
;
551 list_add(&new_pb
->pb_hash_list
, &hash
->bh_list
);
553 XFS_STATS_INC(pb_miss_locked
);
556 spin_unlock(&hash
->bh_lock
);
560 spin_unlock(&hash
->bh_lock
);
562 /* Attempt to get the semaphore without sleeping,
563 * if this does not work then we need to drop the
564 * spinlock and do a hard attempt on the semaphore.
566 if (down_trylock(&pb
->pb_sema
)) {
567 if (!(flags
& PBF_TRYLOCK
)) {
568 /* wait for buffer ownership */
569 PB_TRACE(pb
, "get_lock", 0);
571 XFS_STATS_INC(pb_get_locked_waited
);
573 /* We asked for a trylock and failed, no need
574 * to look at file offset and length here, we
575 * know that this pagebuf at least overlaps our
576 * pagebuf and is locked, therefore our buffer
577 * either does not exist, or is this buffer
581 XFS_STATS_INC(pb_busy_locked
);
589 if (pb
->pb_flags
& PBF_STALE
) {
590 ASSERT((pb
->pb_flags
& _PBF_DELWRI_Q
) == 0);
591 pb
->pb_flags
&= PBF_MAPPED
;
593 PB_TRACE(pb
, "got_lock", 0);
594 XFS_STATS_INC(pb_get_locked
);
599 * xfs_buf_get_flags assembles a buffer covering the specified range.
601 * Storage in memory for all portions of the buffer will be allocated,
602 * although backing storage may not be.
605 xfs_buf_get_flags( /* allocate a buffer */
606 xfs_buftarg_t
*target
,/* target for buffer */
607 loff_t ioff
, /* starting offset of range */
608 size_t isize
, /* length of range */
609 page_buf_flags_t flags
) /* PBF_TRYLOCK */
611 xfs_buf_t
*pb
, *new_pb
;
614 new_pb
= pagebuf_allocate(flags
);
615 if (unlikely(!new_pb
))
618 pb
= _pagebuf_find(target
, ioff
, isize
, flags
, new_pb
);
620 error
= _pagebuf_lookup_pages(pb
, flags
);
624 pagebuf_deallocate(new_pb
);
625 if (unlikely(pb
== NULL
))
629 for (i
= 0; i
< pb
->pb_page_count
; i
++)
630 mark_page_accessed(pb
->pb_pages
[i
]);
632 if (!(pb
->pb_flags
& PBF_MAPPED
)) {
633 error
= _pagebuf_map_pages(pb
, flags
);
634 if (unlikely(error
)) {
635 printk(KERN_WARNING
"%s: failed to map pages\n",
641 XFS_STATS_INC(pb_get
);
644 * Always fill in the block number now, the mapped cases can do
645 * their own overlay of this later.
648 pb
->pb_count_desired
= pb
->pb_buffer_length
;
650 PB_TRACE(pb
, "get", (unsigned long)flags
);
654 if (flags
& (PBF_LOCK
| PBF_TRYLOCK
))
662 xfs_buftarg_t
*target
,
665 page_buf_flags_t flags
)
671 pb
= xfs_buf_get_flags(target
, ioff
, isize
, flags
);
673 if (!XFS_BUF_ISDONE(pb
)) {
674 PB_TRACE(pb
, "read", (unsigned long)flags
);
675 XFS_STATS_INC(pb_get_read
);
676 pagebuf_iostart(pb
, flags
);
677 } else if (flags
& PBF_ASYNC
) {
678 PB_TRACE(pb
, "read_async", (unsigned long)flags
);
680 * Read ahead call which is already satisfied,
685 PB_TRACE(pb
, "read_done", (unsigned long)flags
);
686 /* We do not want read in the flags */
687 pb
->pb_flags
&= ~PBF_READ
;
694 if (flags
& (PBF_LOCK
| PBF_TRYLOCK
))
701 * If we are not low on memory then do the readahead in a deadlock
706 xfs_buftarg_t
*target
,
709 page_buf_flags_t flags
)
711 struct backing_dev_info
*bdi
;
713 bdi
= target
->pbr_mapping
->backing_dev_info
;
714 if (bdi_read_congested(bdi
))
717 flags
|= (PBF_TRYLOCK
|PBF_ASYNC
|PBF_READ_AHEAD
);
718 xfs_buf_read_flags(target
, ioff
, isize
, flags
);
724 xfs_buftarg_t
*target
)
728 pb
= pagebuf_allocate(0);
730 _pagebuf_initialize(pb
, target
, 0, len
, 0);
734 static inline struct page
*
738 if (((unsigned long)addr
< VMALLOC_START
) ||
739 ((unsigned long)addr
>= VMALLOC_END
)) {
740 return virt_to_page(addr
);
742 return vmalloc_to_page(addr
);
747 pagebuf_associate_memory(
759 page_count
= PAGE_CACHE_ALIGN(len
) >> PAGE_CACHE_SHIFT
;
760 offset
= (off_t
) mem
- ((off_t
)mem
& PAGE_CACHE_MASK
);
761 if (offset
&& (len
> PAGE_CACHE_SIZE
))
764 /* Free any previous set of page pointers */
766 _pagebuf_free_pages(pb
);
771 rval
= _pagebuf_get_pages(pb
, page_count
, 0);
775 pb
->pb_offset
= offset
;
776 ptr
= (size_t) mem
& PAGE_CACHE_MASK
;
777 end
= PAGE_CACHE_ALIGN((size_t) mem
+ len
);
779 /* set up first page */
780 pb
->pb_pages
[0] = mem_to_page(mem
);
782 ptr
+= PAGE_CACHE_SIZE
;
783 pb
->pb_page_count
= ++i
;
785 pb
->pb_pages
[i
] = mem_to_page((void *)ptr
);
786 pb
->pb_page_count
= ++i
;
787 ptr
+= PAGE_CACHE_SIZE
;
791 pb
->pb_count_desired
= pb
->pb_buffer_length
= len
;
792 pb
->pb_flags
|= PBF_MAPPED
;
798 pagebuf_get_no_daddr(
800 xfs_buftarg_t
*target
)
802 size_t malloc_len
= len
;
807 bp
= pagebuf_allocate(0);
808 if (unlikely(bp
== NULL
))
810 _pagebuf_initialize(bp
, target
, 0, len
, 0);
813 data
= kmem_alloc(malloc_len
, KM_SLEEP
| KM_MAYFAIL
);
814 if (unlikely(data
== NULL
))
817 /* check whether alignment matches.. */
818 if ((__psunsigned_t
)data
!=
819 ((__psunsigned_t
)data
& ~target
->pbr_smask
)) {
820 /* .. else double the size and try again */
821 kmem_free(data
, malloc_len
);
826 error
= pagebuf_associate_memory(bp
, data
, len
);
829 bp
->pb_flags
|= _PBF_KMEM_ALLOC
;
833 PB_TRACE(bp
, "no_daddr", data
);
836 kmem_free(data
, malloc_len
);
846 * Increment reference count on buffer, to hold the buffer concurrently
847 * with another thread which may release (free) the buffer asynchronously.
849 * Must hold the buffer already to call this function.
855 atomic_inc(&pb
->pb_hold
);
856 PB_TRACE(pb
, "hold", 0);
862 * pagebuf_rele releases a hold on the specified buffer. If the
863 * the hold count is 1, pagebuf_rele calls pagebuf_free.
869 xfs_bufhash_t
*hash
= pb
->pb_hash
;
871 PB_TRACE(pb
, "rele", pb
->pb_relse
);
874 * pagebuf_lookup buffers are not hashed, not delayed write,
875 * and don't have their own release routines. Special case.
877 if (unlikely(!hash
)) {
878 ASSERT(!pb
->pb_relse
);
879 if (atomic_dec_and_test(&pb
->pb_hold
))
884 if (atomic_dec_and_lock(&pb
->pb_hold
, &hash
->bh_lock
)) {
888 atomic_inc(&pb
->pb_hold
);
889 spin_unlock(&hash
->bh_lock
);
890 (*(pb
->pb_relse
)) (pb
);
891 spin_lock(&hash
->bh_lock
);
895 if (pb
->pb_flags
& PBF_FS_MANAGED
) {
900 ASSERT((pb
->pb_flags
& (PBF_DELWRI
|_PBF_DELWRI_Q
)) == 0);
901 list_del_init(&pb
->pb_hash_list
);
902 spin_unlock(&hash
->bh_lock
);
905 spin_unlock(&hash
->bh_lock
);
909 * Catch reference count leaks
911 ASSERT(atomic_read(&pb
->pb_hold
) >= 0);
917 * Mutual exclusion on buffers. Locking model:
919 * Buffers associated with inodes for which buffer locking
920 * is not enabled are not protected by semaphores, and are
921 * assumed to be exclusively owned by the caller. There is a
922 * spinlock in the buffer, used by the caller when concurrent
923 * access is possible.
929 * pagebuf_cond_lock locks a buffer object, if it is not already locked.
930 * Note that this in no way
931 * locks the underlying pages, so it is only useful for synchronizing
932 * concurrent use of page buffer objects, not for synchronizing independent
933 * access to the underlying pages.
936 pagebuf_cond_lock( /* lock buffer, if not locked */
937 /* returns -EBUSY if locked) */
942 locked
= down_trylock(&pb
->pb_sema
) == 0;
946 PB_TRACE(pb
, "cond_lock", (long)locked
);
947 return(locked
? 0 : -EBUSY
);
950 #if defined(DEBUG) || defined(XFS_BLI_TRACE)
954 * Return lock value for a pagebuf
960 return(atomic_read(&pb
->pb_sema
.count
));
967 * pagebuf_lock locks a buffer object. Note that this in no way
968 * locks the underlying pages, so it is only useful for synchronizing
969 * concurrent use of page buffer objects, not for synchronizing independent
970 * access to the underlying pages.
976 PB_TRACE(pb
, "lock", 0);
977 if (atomic_read(&pb
->pb_io_remaining
))
978 blk_run_address_space(pb
->pb_target
->pbr_mapping
);
981 PB_TRACE(pb
, "locked", 0);
988 * pagebuf_unlock releases the lock on the buffer object created by
989 * pagebuf_lock or pagebuf_cond_lock (not any pinning of underlying pages
990 * created by pagebuf_pin).
992 * If the buffer is marked delwri but is not queued, do so before we
993 * unlock the buffer as we need to set flags correctly. We also need to
994 * take a reference for the delwri queue because the unlocker is going to
995 * drop their's and they don't know we just queued it.
998 pagebuf_unlock( /* unlock buffer */
999 xfs_buf_t
*pb
) /* buffer to unlock */
1001 if ((pb
->pb_flags
& (PBF_DELWRI
|_PBF_DELWRI_Q
)) == PBF_DELWRI
) {
1002 atomic_inc(&pb
->pb_hold
);
1003 pb
->pb_flags
|= PBF_ASYNC
;
1004 pagebuf_delwri_queue(pb
, 0);
1009 PB_TRACE(pb
, "unlock", 0);
1014 * Pinning Buffer Storage in Memory
1020 * pagebuf_pin locks all of the memory represented by a buffer in
1021 * memory. Multiple calls to pagebuf_pin and pagebuf_unpin, for
1022 * the same or different buffers affecting a given page, will
1023 * properly count the number of outstanding "pin" requests. The
1024 * buffer may be released after the pagebuf_pin and a different
1025 * buffer used when calling pagebuf_unpin, if desired.
1026 * pagebuf_pin should be used by the file system when it wants be
1027 * assured that no attempt will be made to force the affected
1028 * memory to disk. It does not assure that a given logical page
1029 * will not be moved to a different physical page.
1035 atomic_inc(&pb
->pb_pin_count
);
1036 PB_TRACE(pb
, "pin", (long)pb
->pb_pin_count
.counter
);
1042 * pagebuf_unpin reverses the locking of memory performed by
1043 * pagebuf_pin. Note that both functions affected the logical
1044 * pages associated with the buffer, not the buffer itself.
1050 if (atomic_dec_and_test(&pb
->pb_pin_count
)) {
1051 wake_up_all(&pb
->pb_waiters
);
1053 PB_TRACE(pb
, "unpin", (long)pb
->pb_pin_count
.counter
);
1060 return atomic_read(&pb
->pb_pin_count
);
1064 * pagebuf_wait_unpin
1066 * pagebuf_wait_unpin waits until all of the memory associated
1067 * with the buffer is not longer locked in memory. It returns
1068 * immediately if none of the affected pages are locked.
1071 _pagebuf_wait_unpin(
1074 DECLARE_WAITQUEUE (wait
, current
);
1076 if (atomic_read(&pb
->pb_pin_count
) == 0)
1079 add_wait_queue(&pb
->pb_waiters
, &wait
);
1081 set_current_state(TASK_UNINTERRUPTIBLE
);
1082 if (atomic_read(&pb
->pb_pin_count
) == 0)
1084 if (atomic_read(&pb
->pb_io_remaining
))
1085 blk_run_address_space(pb
->pb_target
->pbr_mapping
);
1088 remove_wait_queue(&pb
->pb_waiters
, &wait
);
1089 set_current_state(TASK_RUNNING
);
1093 * Buffer Utility Routines
1099 * pagebuf_iodone marks a buffer for which I/O is in progress
1100 * done with respect to that I/O. The pb_iodone routine, if
1101 * present, will be called as a side-effect.
1104 pagebuf_iodone_work(
1107 xfs_buf_t
*bp
= (xfs_buf_t
*)v
;
1110 (*(bp
->pb_iodone
))(bp
);
1111 else if (bp
->pb_flags
& PBF_ASYNC
)
1120 pb
->pb_flags
&= ~(PBF_READ
| PBF_WRITE
);
1121 if (pb
->pb_error
== 0)
1122 pb
->pb_flags
&= ~PBF_NONE
;
1124 PB_TRACE(pb
, "iodone", pb
->pb_iodone
);
1126 if ((pb
->pb_iodone
) || (pb
->pb_flags
& PBF_ASYNC
)) {
1128 INIT_WORK(&pb
->pb_iodone_work
, pagebuf_iodone_work
, pb
);
1129 queue_work(xfslogd_workqueue
, &pb
->pb_iodone_work
);
1131 pagebuf_iodone_work(pb
);
1134 up(&pb
->pb_iodonesema
);
1141 * pagebuf_ioerror sets the error code for a buffer.
1144 pagebuf_ioerror( /* mark/clear buffer error flag */
1145 xfs_buf_t
*pb
, /* buffer to mark */
1146 int error
) /* error to store (0 if none) */
1148 ASSERT(error
>= 0 && error
<= 0xffff);
1149 pb
->pb_error
= (unsigned short)error
;
1150 PB_TRACE(pb
, "ioerror", (unsigned long)error
);
1156 * pagebuf_iostart initiates I/O on a buffer, based on the flags supplied.
1157 * If necessary, it will arrange for any disk space allocation required,
1158 * and it will break up the request if the block mappings require it.
1159 * The pb_iodone routine in the buffer supplied will only be called
1160 * when all of the subsidiary I/O requests, if any, have been completed.
1161 * pagebuf_iostart calls the pagebuf_ioinitiate routine or
1162 * pagebuf_iorequest, if the former routine is not defined, to start
1163 * the I/O on a given low-level request.
1166 pagebuf_iostart( /* start I/O on a buffer */
1167 xfs_buf_t
*pb
, /* buffer to start */
1168 page_buf_flags_t flags
) /* PBF_LOCK, PBF_ASYNC, PBF_READ, */
1169 /* PBF_WRITE, PBF_DELWRI, */
1170 /* PBF_DONT_BLOCK */
1174 PB_TRACE(pb
, "iostart", (unsigned long)flags
);
1176 if (flags
& PBF_DELWRI
) {
1177 pb
->pb_flags
&= ~(PBF_READ
| PBF_WRITE
| PBF_ASYNC
);
1178 pb
->pb_flags
|= flags
& (PBF_DELWRI
| PBF_ASYNC
);
1179 pagebuf_delwri_queue(pb
, 1);
1183 pb
->pb_flags
&= ~(PBF_READ
| PBF_WRITE
| PBF_ASYNC
| PBF_DELWRI
| \
1184 PBF_READ_AHEAD
| _PBF_RUN_QUEUES
);
1185 pb
->pb_flags
|= flags
& (PBF_READ
| PBF_WRITE
| PBF_ASYNC
| \
1186 PBF_READ_AHEAD
| _PBF_RUN_QUEUES
);
1188 BUG_ON(pb
->pb_bn
== XFS_BUF_DADDR_NULL
);
1190 /* For writes allow an alternate strategy routine to precede
1191 * the actual I/O request (which may not be issued at all in
1192 * a shutdown situation, for example).
1194 status
= (flags
& PBF_WRITE
) ?
1195 pagebuf_iostrategy(pb
) : pagebuf_iorequest(pb
);
1197 /* Wait for I/O if we are not an async request.
1198 * Note: async I/O request completion will release the buffer,
1199 * and that can already be done by this point. So using the
1200 * buffer pointer from here on, after async I/O, is invalid.
1202 if (!status
&& !(flags
& PBF_ASYNC
))
1203 status
= pagebuf_iowait(pb
);
1209 * Helper routine for pagebuf_iorequest
1212 STATIC __inline__
int
1216 ASSERT(pb
->pb_flags
& (PBF_READ
|PBF_WRITE
));
1217 if (pb
->pb_flags
& PBF_READ
)
1218 return pb
->pb_locked
;
1222 STATIC __inline__
void
1227 if (atomic_dec_and_test(&pb
->pb_io_remaining
) == 1) {
1229 pagebuf_iodone(pb
, schedule
);
1236 unsigned int bytes_done
,
1239 xfs_buf_t
*pb
= (xfs_buf_t
*)bio
->bi_private
;
1240 unsigned int blocksize
= pb
->pb_target
->pbr_bsize
;
1241 struct bio_vec
*bvec
= bio
->bi_io_vec
+ bio
->bi_vcnt
- 1;
1246 if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1250 struct page
*page
= bvec
->bv_page
;
1252 if (unlikely(pb
->pb_error
)) {
1253 if (pb
->pb_flags
& PBF_READ
)
1254 ClearPageUptodate(page
);
1256 } else if (blocksize
== PAGE_CACHE_SIZE
) {
1257 SetPageUptodate(page
);
1258 } else if (!PagePrivate(page
) &&
1259 (pb
->pb_flags
& _PBF_PAGE_CACHE
)) {
1260 set_page_region(page
, bvec
->bv_offset
, bvec
->bv_len
);
1263 if (--bvec
>= bio
->bi_io_vec
)
1264 prefetchw(&bvec
->bv_page
->flags
);
1266 if (_pagebuf_iolocked(pb
)) {
1269 } while (bvec
>= bio
->bi_io_vec
);
1271 _pagebuf_iodone(pb
, 1);
1280 int i
, rw
, map_i
, total_nr_pages
, nr_pages
;
1282 int offset
= pb
->pb_offset
;
1283 int size
= pb
->pb_count_desired
;
1284 sector_t sector
= pb
->pb_bn
;
1285 unsigned int blocksize
= pb
->pb_target
->pbr_bsize
;
1286 int locking
= _pagebuf_iolocked(pb
);
1288 total_nr_pages
= pb
->pb_page_count
;
1291 if (pb
->pb_flags
& _PBF_RUN_QUEUES
) {
1292 pb
->pb_flags
&= ~_PBF_RUN_QUEUES
;
1293 rw
= (pb
->pb_flags
& PBF_READ
) ? READ_SYNC
: WRITE_SYNC
;
1295 rw
= (pb
->pb_flags
& PBF_READ
) ? READ
: WRITE
;
1298 /* Special code path for reading a sub page size pagebuf in --
1299 * we populate up the whole page, and hence the other metadata
1300 * in the same page. This optimization is only valid when the
1301 * filesystem block size and the page size are equal.
1303 if ((pb
->pb_buffer_length
< PAGE_CACHE_SIZE
) &&
1304 (pb
->pb_flags
& PBF_READ
) && locking
&&
1305 (blocksize
== PAGE_CACHE_SIZE
)) {
1306 bio
= bio_alloc(GFP_NOIO
, 1);
1308 bio
->bi_bdev
= pb
->pb_target
->pbr_bdev
;
1309 bio
->bi_sector
= sector
- (offset
>> BBSHIFT
);
1310 bio
->bi_end_io
= bio_end_io_pagebuf
;
1311 bio
->bi_private
= pb
;
1313 bio_add_page(bio
, pb
->pb_pages
[0], PAGE_CACHE_SIZE
, 0);
1316 atomic_inc(&pb
->pb_io_remaining
);
1321 /* Lock down the pages which we need to for the request */
1322 if (locking
&& (pb
->pb_flags
& PBF_WRITE
) && (pb
->pb_locked
== 0)) {
1323 for (i
= 0; size
; i
++) {
1324 int nbytes
= PAGE_CACHE_SIZE
- offset
;
1325 struct page
*page
= pb
->pb_pages
[i
];
1335 offset
= pb
->pb_offset
;
1336 size
= pb
->pb_count_desired
;
1340 atomic_inc(&pb
->pb_io_remaining
);
1341 nr_pages
= BIO_MAX_SECTORS
>> (PAGE_SHIFT
- BBSHIFT
);
1342 if (nr_pages
> total_nr_pages
)
1343 nr_pages
= total_nr_pages
;
1345 bio
= bio_alloc(GFP_NOIO
, nr_pages
);
1346 bio
->bi_bdev
= pb
->pb_target
->pbr_bdev
;
1347 bio
->bi_sector
= sector
;
1348 bio
->bi_end_io
= bio_end_io_pagebuf
;
1349 bio
->bi_private
= pb
;
1351 for (; size
&& nr_pages
; nr_pages
--, map_i
++) {
1352 int nbytes
= PAGE_CACHE_SIZE
- offset
;
1357 if (bio_add_page(bio
, pb
->pb_pages
[map_i
],
1358 nbytes
, offset
) < nbytes
)
1362 sector
+= nbytes
>> BBSHIFT
;
1368 if (likely(bio
->bi_size
)) {
1369 submit_bio(rw
, bio
);
1374 pagebuf_ioerror(pb
, EIO
);
1379 * pagebuf_iorequest -- the core I/O request routine.
1382 pagebuf_iorequest( /* start real I/O */
1383 xfs_buf_t
*pb
) /* buffer to convey to device */
1385 PB_TRACE(pb
, "iorequest", 0);
1387 if (pb
->pb_flags
& PBF_DELWRI
) {
1388 pagebuf_delwri_queue(pb
, 1);
1392 if (pb
->pb_flags
& PBF_WRITE
) {
1393 _pagebuf_wait_unpin(pb
);
1398 /* Set the count to 1 initially, this will stop an I/O
1399 * completion callout which happens before we have started
1400 * all the I/O from calling pagebuf_iodone too early.
1402 atomic_set(&pb
->pb_io_remaining
, 1);
1403 _pagebuf_ioapply(pb
);
1404 _pagebuf_iodone(pb
, 0);
1413 * pagebuf_iowait waits for I/O to complete on the buffer supplied.
1414 * It returns immediately if no I/O is pending. In any case, it returns
1415 * the error code, if any, or 0 if there is no error.
1421 PB_TRACE(pb
, "iowait", 0);
1422 if (atomic_read(&pb
->pb_io_remaining
))
1423 blk_run_address_space(pb
->pb_target
->pbr_mapping
);
1424 down(&pb
->pb_iodonesema
);
1425 PB_TRACE(pb
, "iowaited", (long)pb
->pb_error
);
1426 return pb
->pb_error
;
1436 offset
+= pb
->pb_offset
;
1438 page
= pb
->pb_pages
[offset
>> PAGE_CACHE_SHIFT
];
1439 return (caddr_t
) page_address(page
) + (offset
& (PAGE_CACHE_SIZE
- 1));
1445 * Move data into or out of a buffer.
1449 xfs_buf_t
*pb
, /* buffer to process */
1450 size_t boff
, /* starting buffer offset */
1451 size_t bsize
, /* length to copy */
1452 caddr_t data
, /* data address */
1453 page_buf_rw_t mode
) /* read/write flag */
1455 size_t bend
, cpoff
, csize
;
1458 bend
= boff
+ bsize
;
1459 while (boff
< bend
) {
1460 page
= pb
->pb_pages
[page_buf_btoct(boff
+ pb
->pb_offset
)];
1461 cpoff
= page_buf_poff(boff
+ pb
->pb_offset
);
1462 csize
= min_t(size_t,
1463 PAGE_CACHE_SIZE
-cpoff
, pb
->pb_count_desired
-boff
);
1465 ASSERT(((csize
+ cpoff
) <= PAGE_CACHE_SIZE
));
1469 memset(page_address(page
) + cpoff
, 0, csize
);
1472 memcpy(data
, page_address(page
) + cpoff
, csize
);
1475 memcpy(page_address(page
) + cpoff
, data
, csize
);
1484 * Handling of buftargs.
1488 * Wait for any bufs with callbacks that have been submitted but
1489 * have not yet returned... walk the hash list for the target.
1496 xfs_bufhash_t
*hash
;
1499 for (i
= 0; i
< (1 << btp
->bt_hashshift
); i
++) {
1500 hash
= &btp
->bt_hash
[i
];
1502 spin_lock(&hash
->bh_lock
);
1503 list_for_each_entry_safe(bp
, n
, &hash
->bh_list
, pb_hash_list
) {
1504 ASSERT(btp
== bp
->pb_target
);
1505 if (!(bp
->pb_flags
& PBF_FS_MANAGED
)) {
1506 spin_unlock(&hash
->bh_lock
);
1508 * Catch superblock reference count leaks
1511 BUG_ON(bp
->pb_bn
== 0);
1516 spin_unlock(&hash
->bh_lock
);
1521 * Allocate buffer hash table for a given target.
1522 * For devices containing metadata (i.e. not the log/realtime devices)
1523 * we need to allocate a much larger hash table.
1532 btp
->bt_hashshift
= external
? 3 : 8; /* 8 or 256 buckets */
1533 btp
->bt_hashmask
= (1 << btp
->bt_hashshift
) - 1;
1534 btp
->bt_hash
= kmem_zalloc((1 << btp
->bt_hashshift
) *
1535 sizeof(xfs_bufhash_t
), KM_SLEEP
);
1536 for (i
= 0; i
< (1 << btp
->bt_hashshift
); i
++) {
1537 spin_lock_init(&btp
->bt_hash
[i
].bh_lock
);
1538 INIT_LIST_HEAD(&btp
->bt_hash
[i
].bh_list
);
1546 kmem_free(btp
->bt_hash
,
1547 (1 << btp
->bt_hashshift
) * sizeof(xfs_bufhash_t
));
1548 btp
->bt_hash
= NULL
;
1556 xfs_flush_buftarg(btp
, 1);
1558 xfs_blkdev_put(btp
->pbr_bdev
);
1559 xfs_free_bufhash(btp
);
1560 iput(btp
->pbr_mapping
->host
);
1561 kmem_free(btp
, sizeof(*btp
));
1565 xfs_setsize_buftarg_flags(
1567 unsigned int blocksize
,
1568 unsigned int sectorsize
,
1571 btp
->pbr_bsize
= blocksize
;
1572 btp
->pbr_sshift
= ffs(sectorsize
) - 1;
1573 btp
->pbr_smask
= sectorsize
- 1;
1575 if (set_blocksize(btp
->pbr_bdev
, sectorsize
)) {
1577 "XFS: Cannot set_blocksize to %u on device %s\n",
1578 sectorsize
, XFS_BUFTARG_NAME(btp
));
1583 (PAGE_CACHE_SIZE
/ BITS_PER_LONG
) > sectorsize
) {
1585 "XFS: %u byte sectors in use on device %s. "
1586 "This is suboptimal; %u or greater is ideal.\n",
1587 sectorsize
, XFS_BUFTARG_NAME(btp
),
1588 (unsigned int)PAGE_CACHE_SIZE
/ BITS_PER_LONG
);
1595 * When allocating the initial buffer target we have not yet
1596 * read in the superblock, so don't know what sized sectors
1597 * are being used is at this early stage. Play safe.
1600 xfs_setsize_buftarg_early(
1602 struct block_device
*bdev
)
1604 return xfs_setsize_buftarg_flags(btp
,
1605 PAGE_CACHE_SIZE
, bdev_hardsect_size(bdev
), 0);
1609 xfs_setsize_buftarg(
1611 unsigned int blocksize
,
1612 unsigned int sectorsize
)
1614 return xfs_setsize_buftarg_flags(btp
, blocksize
, sectorsize
, 1);
1618 xfs_mapping_buftarg(
1620 struct block_device
*bdev
)
1622 struct backing_dev_info
*bdi
;
1623 struct inode
*inode
;
1624 struct address_space
*mapping
;
1625 static struct address_space_operations mapping_aops
= {
1626 .sync_page
= block_sync_page
,
1629 inode
= new_inode(bdev
->bd_inode
->i_sb
);
1632 "XFS: Cannot allocate mapping inode for device %s\n",
1633 XFS_BUFTARG_NAME(btp
));
1636 inode
->i_mode
= S_IFBLK
;
1637 inode
->i_bdev
= bdev
;
1638 inode
->i_rdev
= bdev
->bd_dev
;
1639 bdi
= blk_get_backing_dev_info(bdev
);
1641 bdi
= &default_backing_dev_info
;
1642 mapping
= &inode
->i_data
;
1643 mapping
->a_ops
= &mapping_aops
;
1644 mapping
->backing_dev_info
= bdi
;
1645 mapping_set_gfp_mask(mapping
, GFP_NOFS
);
1646 btp
->pbr_mapping
= mapping
;
1652 struct block_device
*bdev
,
1657 btp
= kmem_zalloc(sizeof(*btp
), KM_SLEEP
);
1659 btp
->pbr_dev
= bdev
->bd_dev
;
1660 btp
->pbr_bdev
= bdev
;
1661 if (xfs_setsize_buftarg_early(btp
, bdev
))
1663 if (xfs_mapping_buftarg(btp
, bdev
))
1665 xfs_alloc_bufhash(btp
, external
);
1669 kmem_free(btp
, sizeof(*btp
));
1675 * Pagebuf delayed write buffer handling
1678 STATIC
LIST_HEAD(pbd_delwrite_queue
);
1679 STATIC
DEFINE_SPINLOCK(pbd_delwrite_lock
);
1682 pagebuf_delwri_queue(
1686 PB_TRACE(pb
, "delwri_q", (long)unlock
);
1687 ASSERT((pb
->pb_flags
& (PBF_DELWRI
|PBF_ASYNC
)) ==
1688 (PBF_DELWRI
|PBF_ASYNC
));
1690 spin_lock(&pbd_delwrite_lock
);
1691 /* If already in the queue, dequeue and place at tail */
1692 if (!list_empty(&pb
->pb_list
)) {
1693 ASSERT(pb
->pb_flags
& _PBF_DELWRI_Q
);
1695 atomic_dec(&pb
->pb_hold
);
1697 list_del(&pb
->pb_list
);
1700 pb
->pb_flags
|= _PBF_DELWRI_Q
;
1701 list_add_tail(&pb
->pb_list
, &pbd_delwrite_queue
);
1702 pb
->pb_queuetime
= jiffies
;
1703 spin_unlock(&pbd_delwrite_lock
);
1710 pagebuf_delwri_dequeue(
1715 spin_lock(&pbd_delwrite_lock
);
1716 if ((pb
->pb_flags
& PBF_DELWRI
) && !list_empty(&pb
->pb_list
)) {
1717 ASSERT(pb
->pb_flags
& _PBF_DELWRI_Q
);
1718 list_del_init(&pb
->pb_list
);
1721 pb
->pb_flags
&= ~(PBF_DELWRI
|_PBF_DELWRI_Q
);
1722 spin_unlock(&pbd_delwrite_lock
);
1727 PB_TRACE(pb
, "delwri_dq", (long)dequeued
);
1731 pagebuf_runall_queues(
1732 struct workqueue_struct
*queue
)
1734 flush_workqueue(queue
);
1737 /* Defines for pagebuf daemon */
1738 STATIC
struct task_struct
*xfsbufd_task
;
1739 STATIC
int xfsbufd_force_flush
;
1740 STATIC
int xfsbufd_force_sleep
;
1747 if (xfsbufd_force_sleep
)
1749 xfsbufd_force_flush
= 1;
1751 wake_up_process(xfsbufd_task
);
1759 struct list_head tmp
;
1761 xfs_buftarg_t
*target
;
1764 current
->flags
|= PF_MEMALLOC
;
1766 INIT_LIST_HEAD(&tmp
);
1768 if (unlikely(freezing(current
))) {
1769 xfsbufd_force_sleep
= 1;
1772 xfsbufd_force_sleep
= 0;
1775 schedule_timeout_interruptible
1776 (xfs_buf_timer_centisecs
* msecs_to_jiffies(10));
1778 age
= xfs_buf_age_centisecs
* msecs_to_jiffies(10);
1779 spin_lock(&pbd_delwrite_lock
);
1780 list_for_each_entry_safe(pb
, n
, &pbd_delwrite_queue
, pb_list
) {
1781 PB_TRACE(pb
, "walkq1", (long)pagebuf_ispin(pb
));
1782 ASSERT(pb
->pb_flags
& PBF_DELWRI
);
1784 if (!pagebuf_ispin(pb
) && !pagebuf_cond_lock(pb
)) {
1785 if (!xfsbufd_force_flush
&&
1786 time_before(jiffies
,
1787 pb
->pb_queuetime
+ age
)) {
1792 pb
->pb_flags
&= ~(PBF_DELWRI
|_PBF_DELWRI_Q
);
1793 pb
->pb_flags
|= PBF_WRITE
;
1794 list_move(&pb
->pb_list
, &tmp
);
1797 spin_unlock(&pbd_delwrite_lock
);
1799 while (!list_empty(&tmp
)) {
1800 pb
= list_entry(tmp
.next
, xfs_buf_t
, pb_list
);
1801 target
= pb
->pb_target
;
1803 list_del_init(&pb
->pb_list
);
1804 pagebuf_iostrategy(pb
);
1806 blk_run_address_space(target
->pbr_mapping
);
1809 if (as_list_len
> 0)
1812 xfsbufd_force_flush
= 0;
1813 } while (!kthread_should_stop());
1819 * Go through all incore buffers, and release buffers if they belong to
1820 * the given device. This is used in filesystem error handling to
1821 * preserve the consistency of its metadata.
1825 xfs_buftarg_t
*target
,
1828 struct list_head tmp
;
1832 pagebuf_runall_queues(xfsdatad_workqueue
);
1833 pagebuf_runall_queues(xfslogd_workqueue
);
1835 INIT_LIST_HEAD(&tmp
);
1836 spin_lock(&pbd_delwrite_lock
);
1837 list_for_each_entry_safe(pb
, n
, &pbd_delwrite_queue
, pb_list
) {
1839 if (pb
->pb_target
!= target
)
1842 ASSERT(pb
->pb_flags
& (PBF_DELWRI
|_PBF_DELWRI_Q
));
1843 PB_TRACE(pb
, "walkq2", (long)pagebuf_ispin(pb
));
1844 if (pagebuf_ispin(pb
)) {
1849 list_move(&pb
->pb_list
, &tmp
);
1851 spin_unlock(&pbd_delwrite_lock
);
1854 * Dropped the delayed write list lock, now walk the temporary list
1856 list_for_each_entry_safe(pb
, n
, &tmp
, pb_list
) {
1858 pb
->pb_flags
&= ~(PBF_DELWRI
|_PBF_DELWRI_Q
);
1859 pb
->pb_flags
|= PBF_WRITE
;
1861 pb
->pb_flags
&= ~PBF_ASYNC
;
1863 list_del_init(&pb
->pb_list
);
1865 pagebuf_iostrategy(pb
);
1869 * Remaining list items must be flushed before returning
1871 while (!list_empty(&tmp
)) {
1872 pb
= list_entry(tmp
.next
, xfs_buf_t
, pb_list
);
1874 list_del_init(&pb
->pb_list
);
1880 blk_run_address_space(target
->pbr_mapping
);
1888 int error
= -ENOMEM
;
1890 #ifdef PAGEBUF_TRACE
1891 pagebuf_trace_buf
= ktrace_alloc(PAGEBUF_TRACE_SIZE
, KM_SLEEP
);
1894 pagebuf_zone
= kmem_zone_init(sizeof(xfs_buf_t
), "xfs_buf");
1896 goto out_free_trace_buf
;
1898 xfslogd_workqueue
= create_workqueue("xfslogd");
1899 if (!xfslogd_workqueue
)
1900 goto out_free_buf_zone
;
1902 xfsdatad_workqueue
= create_workqueue("xfsdatad");
1903 if (!xfsdatad_workqueue
)
1904 goto out_destroy_xfslogd_workqueue
;
1906 xfsbufd_task
= kthread_run(xfsbufd
, NULL
, "xfsbufd");
1907 if (IS_ERR(xfsbufd_task
)) {
1908 error
= PTR_ERR(xfsbufd_task
);
1909 goto out_destroy_xfsdatad_workqueue
;
1912 pagebuf_shake
= kmem_shake_register(xfsbufd_wakeup
);
1914 goto out_stop_xfsbufd
;
1919 kthread_stop(xfsbufd_task
);
1920 out_destroy_xfsdatad_workqueue
:
1921 destroy_workqueue(xfsdatad_workqueue
);
1922 out_destroy_xfslogd_workqueue
:
1923 destroy_workqueue(xfslogd_workqueue
);
1925 kmem_zone_destroy(pagebuf_zone
);
1927 #ifdef PAGEBUF_TRACE
1928 ktrace_free(pagebuf_trace_buf
);
1934 pagebuf_terminate(void)
1936 kmem_shake_deregister(pagebuf_shake
);
1937 kthread_stop(xfsbufd_task
);
1938 destroy_workqueue(xfsdatad_workqueue
);
1939 destroy_workqueue(xfslogd_workqueue
);
1940 kmem_zone_destroy(pagebuf_zone
);
1941 #ifdef PAGEBUF_TRACE
1942 ktrace_free(pagebuf_trace_buf
);