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21#include <linux/kernel.h>
22#include <linux/syscalls.h>
23#include <linux/fs.h>
24#include <linux/mm.h>
25#include <linux/percpu.h>
26#include <linux/slab.h>
27#include <linux/capability.h>
28#include <linux/blkdev.h>
29#include <linux/file.h>
30#include <linux/quotaops.h>
31#include <linux/highmem.h>
32#include <linux/module.h>
33#include <linux/writeback.h>
34#include <linux/hash.h>
35#include <linux/suspend.h>
36#include <linux/buffer_head.h>
37#include <linux/task_io_accounting_ops.h>
38#include <linux/bio.h>
39#include <linux/notifier.h>
40#include <linux/cpu.h>
41#include <linux/bitops.h>
42#include <linux/mpage.h>
43#include <linux/bit_spinlock.h>
44
45static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
46
47#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
48
49inline void
50init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private)
51{
52 bh->b_end_io = handler;
53 bh->b_private = private;
54}
55EXPORT_SYMBOL(init_buffer);
56
57static int sync_buffer(void *word)
58{
59 struct block_device *bd;
60 struct buffer_head *bh
61 = container_of(word, struct buffer_head, b_state);
62
63 smp_mb();
64 bd = bh->b_bdev;
65 if (bd)
66 blk_run_address_space(bd->bd_inode->i_mapping);
67 io_schedule();
68 return 0;
69}
70
71void __lock_buffer(struct buffer_head *bh)
72{
73 wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer,
74 TASK_UNINTERRUPTIBLE);
75}
76EXPORT_SYMBOL(__lock_buffer);
77
78void unlock_buffer(struct buffer_head *bh)
79{
80 clear_bit_unlock(BH_Lock, &bh->b_state);
81 smp_mb__after_clear_bit();
82 wake_up_bit(&bh->b_state, BH_Lock);
83}
84EXPORT_SYMBOL(unlock_buffer);
85
86
87
88
89
90
91void __wait_on_buffer(struct buffer_head * bh)
92{
93 wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE);
94}
95EXPORT_SYMBOL(__wait_on_buffer);
96
97static void
98__clear_page_buffers(struct page *page)
99{
100 ClearPagePrivate(page);
101 set_page_private(page, 0);
102 page_cache_release(page);
103}
104
105
106static int quiet_error(struct buffer_head *bh)
107{
108 if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit())
109 return 0;
110 return 1;
111}
112
113
114static void buffer_io_error(struct buffer_head *bh)
115{
116 char b[BDEVNAME_SIZE];
117 printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
118 bdevname(bh->b_bdev, b),
119 (unsigned long long)bh->b_blocknr);
120}
121
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127
128
129
130static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate)
131{
132 if (uptodate) {
133 set_buffer_uptodate(bh);
134 } else {
135
136 clear_buffer_uptodate(bh);
137 }
138 unlock_buffer(bh);
139}
140
141
142
143
144
145void end_buffer_read_sync(struct buffer_head *bh, int uptodate)
146{
147 __end_buffer_read_notouch(bh, uptodate);
148 put_bh(bh);
149}
150EXPORT_SYMBOL(end_buffer_read_sync);
151
152void end_buffer_write_sync(struct buffer_head *bh, int uptodate)
153{
154 char b[BDEVNAME_SIZE];
155
156 if (uptodate) {
157 set_buffer_uptodate(bh);
158 } else {
159 if (!buffer_eopnotsupp(bh) && !quiet_error(bh)) {
160 buffer_io_error(bh);
161 printk(KERN_WARNING "lost page write due to "
162 "I/O error on %s\n",
163 bdevname(bh->b_bdev, b));
164 }
165 set_buffer_write_io_error(bh);
166 clear_buffer_uptodate(bh);
167 }
168 unlock_buffer(bh);
169 put_bh(bh);
170}
171EXPORT_SYMBOL(end_buffer_write_sync);
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183
184static struct buffer_head *
185__find_get_block_slow(struct block_device *bdev, sector_t block)
186{
187 struct inode *bd_inode = bdev->bd_inode;
188 struct address_space *bd_mapping = bd_inode->i_mapping;
189 struct buffer_head *ret = NULL;
190 pgoff_t index;
191 struct buffer_head *bh;
192 struct buffer_head *head;
193 struct page *page;
194 int all_mapped = 1;
195
196 index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits);
197 page = find_get_page(bd_mapping, index);
198 if (!page)
199 goto out;
200
201 spin_lock(&bd_mapping->private_lock);
202 if (!page_has_buffers(page))
203 goto out_unlock;
204 head = page_buffers(page);
205 bh = head;
206 do {
207 if (!buffer_mapped(bh))
208 all_mapped = 0;
209 else if (bh->b_blocknr == block) {
210 ret = bh;
211 get_bh(bh);
212 goto out_unlock;
213 }
214 bh = bh->b_this_page;
215 } while (bh != head);
216
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220
221
222 if (all_mapped) {
223 printk("__find_get_block_slow() failed. "
224 "block=%llu, b_blocknr=%llu\n",
225 (unsigned long long)block,
226 (unsigned long long)bh->b_blocknr);
227 printk("b_state=0x%08lx, b_size=%zu\n",
228 bh->b_state, bh->b_size);
229 printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits);
230 }
231out_unlock:
232 spin_unlock(&bd_mapping->private_lock);
233 page_cache_release(page);
234out:
235 return ret;
236}
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269
270void invalidate_bdev(struct block_device *bdev)
271{
272 struct address_space *mapping = bdev->bd_inode->i_mapping;
273
274 if (mapping->nrpages == 0)
275 return;
276
277 invalidate_bh_lrus();
278 invalidate_mapping_pages(mapping, 0, -1);
279}
280EXPORT_SYMBOL(invalidate_bdev);
281
282
283
284
285static void free_more_memory(void)
286{
287 struct zone *zone;
288 int nid;
289
290 wakeup_flusher_threads(1024);
291 yield();
292
293 for_each_online_node(nid) {
294 (void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS),
295 gfp_zone(GFP_NOFS), NULL,
296 &zone);
297 if (zone)
298 try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0,
299 GFP_NOFS, NULL);
300 }
301}
302
303
304
305
306
307static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
308{
309 unsigned long flags;
310 struct buffer_head *first;
311 struct buffer_head *tmp;
312 struct page *page;
313 int page_uptodate = 1;
314
315 BUG_ON(!buffer_async_read(bh));
316
317 page = bh->b_page;
318 if (uptodate) {
319 set_buffer_uptodate(bh);
320 } else {
321 clear_buffer_uptodate(bh);
322 if (!quiet_error(bh))
323 buffer_io_error(bh);
324 SetPageError(page);
325 }
326
327
328
329
330
331
332 first = page_buffers(page);
333 local_irq_save(flags);
334 bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
335 clear_buffer_async_read(bh);
336 unlock_buffer(bh);
337 tmp = bh;
338 do {
339 if (!buffer_uptodate(tmp))
340 page_uptodate = 0;
341 if (buffer_async_read(tmp)) {
342 BUG_ON(!buffer_locked(tmp));
343 goto still_busy;
344 }
345 tmp = tmp->b_this_page;
346 } while (tmp != bh);
347 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
348 local_irq_restore(flags);
349
350
351
352
353
354 if (page_uptodate && !PageError(page))
355 SetPageUptodate(page);
356 unlock_page(page);
357 return;
358
359still_busy:
360 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
361 local_irq_restore(flags);
362 return;
363}
364
365
366
367
368
369void end_buffer_async_write(struct buffer_head *bh, int uptodate)
370{
371 char b[BDEVNAME_SIZE];
372 unsigned long flags;
373 struct buffer_head *first;
374 struct buffer_head *tmp;
375 struct page *page;
376
377 BUG_ON(!buffer_async_write(bh));
378
379 page = bh->b_page;
380 if (uptodate) {
381 set_buffer_uptodate(bh);
382 } else {
383 if (!quiet_error(bh)) {
384 buffer_io_error(bh);
385 printk(KERN_WARNING "lost page write due to "
386 "I/O error on %s\n",
387 bdevname(bh->b_bdev, b));
388 }
389 set_bit(AS_EIO, &page->mapping->flags);
390 set_buffer_write_io_error(bh);
391 clear_buffer_uptodate(bh);
392 SetPageError(page);
393 }
394
395 first = page_buffers(page);
396 local_irq_save(flags);
397 bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
398
399 clear_buffer_async_write(bh);
400 unlock_buffer(bh);
401 tmp = bh->b_this_page;
402 while (tmp != bh) {
403 if (buffer_async_write(tmp)) {
404 BUG_ON(!buffer_locked(tmp));
405 goto still_busy;
406 }
407 tmp = tmp->b_this_page;
408 }
409 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
410 local_irq_restore(flags);
411 end_page_writeback(page);
412 return;
413
414still_busy:
415 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
416 local_irq_restore(flags);
417 return;
418}
419EXPORT_SYMBOL(end_buffer_async_write);
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442static void mark_buffer_async_read(struct buffer_head *bh)
443{
444 bh->b_end_io = end_buffer_async_read;
445 set_buffer_async_read(bh);
446}
447
448static void mark_buffer_async_write_endio(struct buffer_head *bh,
449 bh_end_io_t *handler)
450{
451 bh->b_end_io = handler;
452 set_buffer_async_write(bh);
453}
454
455void mark_buffer_async_write(struct buffer_head *bh)
456{
457 mark_buffer_async_write_endio(bh, end_buffer_async_write);
458}
459EXPORT_SYMBOL(mark_buffer_async_write);
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514static void __remove_assoc_queue(struct buffer_head *bh)
515{
516 list_del_init(&bh->b_assoc_buffers);
517 WARN_ON(!bh->b_assoc_map);
518 if (buffer_write_io_error(bh))
519 set_bit(AS_EIO, &bh->b_assoc_map->flags);
520 bh->b_assoc_map = NULL;
521}
522
523int inode_has_buffers(struct inode *inode)
524{
525 return !list_empty(&inode->i_data.private_list);
526}
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538static int osync_buffers_list(spinlock_t *lock, struct list_head *list)
539{
540 struct buffer_head *bh;
541 struct list_head *p;
542 int err = 0;
543
544 spin_lock(lock);
545repeat:
546 list_for_each_prev(p, list) {
547 bh = BH_ENTRY(p);
548 if (buffer_locked(bh)) {
549 get_bh(bh);
550 spin_unlock(lock);
551 wait_on_buffer(bh);
552 if (!buffer_uptodate(bh))
553 err = -EIO;
554 brelse(bh);
555 spin_lock(lock);
556 goto repeat;
557 }
558 }
559 spin_unlock(lock);
560 return err;
561}
562
563static void do_thaw_all(struct work_struct *work)
564{
565 struct super_block *sb;
566 char b[BDEVNAME_SIZE];
567
568 spin_lock(&sb_lock);
569restart:
570 list_for_each_entry(sb, &super_blocks, s_list) {
571 sb->s_count++;
572 spin_unlock(&sb_lock);
573 down_read(&sb->s_umount);
574 while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
575 printk(KERN_WARNING "Emergency Thaw on %s\n",
576 bdevname(sb->s_bdev, b));
577 up_read(&sb->s_umount);
578 spin_lock(&sb_lock);
579 if (__put_super_and_need_restart(sb))
580 goto restart;
581 }
582 spin_unlock(&sb_lock);
583 kfree(work);
584 printk(KERN_WARNING "Emergency Thaw complete\n");
585}
586
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590
591
592void emergency_thaw_all(void)
593{
594 struct work_struct *work;
595
596 work = kmalloc(sizeof(*work), GFP_ATOMIC);
597 if (work) {
598 INIT_WORK(work, do_thaw_all);
599 schedule_work(work);
600 }
601}
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614int sync_mapping_buffers(struct address_space *mapping)
615{
616 struct address_space *buffer_mapping = mapping->assoc_mapping;
617
618 if (buffer_mapping == NULL || list_empty(&mapping->private_list))
619 return 0;
620
621 return fsync_buffers_list(&buffer_mapping->private_lock,
622 &mapping->private_list);
623}
624EXPORT_SYMBOL(sync_mapping_buffers);
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631
632void write_boundary_block(struct block_device *bdev,
633 sector_t bblock, unsigned blocksize)
634{
635 struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize);
636 if (bh) {
637 if (buffer_dirty(bh))
638 ll_rw_block(WRITE, 1, &bh);
639 put_bh(bh);
640 }
641}
642
643void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode)
644{
645 struct address_space *mapping = inode->i_mapping;
646 struct address_space *buffer_mapping = bh->b_page->mapping;
647
648 mark_buffer_dirty(bh);
649 if (!mapping->assoc_mapping) {
650 mapping->assoc_mapping = buffer_mapping;
651 } else {
652 BUG_ON(mapping->assoc_mapping != buffer_mapping);
653 }
654 if (!bh->b_assoc_map) {
655 spin_lock(&buffer_mapping->private_lock);
656 list_move_tail(&bh->b_assoc_buffers,
657 &mapping->private_list);
658 bh->b_assoc_map = mapping;
659 spin_unlock(&buffer_mapping->private_lock);
660 }
661}
662EXPORT_SYMBOL(mark_buffer_dirty_inode);
663
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669
670
671static void __set_page_dirty(struct page *page,
672 struct address_space *mapping, int warn)
673{
674 spin_lock_irq(&mapping->tree_lock);
675 if (page->mapping) {
676 WARN_ON_ONCE(warn && !PageUptodate(page));
677 account_page_dirtied(page, mapping);
678 radix_tree_tag_set(&mapping->page_tree,
679 page_index(page), PAGECACHE_TAG_DIRTY);
680 }
681 spin_unlock_irq(&mapping->tree_lock);
682 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
683}
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710int __set_page_dirty_buffers(struct page *page)
711{
712 int newly_dirty;
713 struct address_space *mapping = page_mapping(page);
714
715 if (unlikely(!mapping))
716 return !TestSetPageDirty(page);
717
718 spin_lock(&mapping->private_lock);
719 if (page_has_buffers(page)) {
720 struct buffer_head *head = page_buffers(page);
721 struct buffer_head *bh = head;
722
723 do {
724 set_buffer_dirty(bh);
725 bh = bh->b_this_page;
726 } while (bh != head);
727 }
728 newly_dirty = !TestSetPageDirty(page);
729 spin_unlock(&mapping->private_lock);
730
731 if (newly_dirty)
732 __set_page_dirty(page, mapping, 1);
733 return newly_dirty;
734}
735EXPORT_SYMBOL(__set_page_dirty_buffers);
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755
756static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
757{
758 struct buffer_head *bh;
759 struct list_head tmp;
760 struct address_space *mapping, *prev_mapping = NULL;
761 int err = 0, err2;
762
763 INIT_LIST_HEAD(&tmp);
764
765 spin_lock(lock);
766 while (!list_empty(list)) {
767 bh = BH_ENTRY(list->next);
768 mapping = bh->b_assoc_map;
769 __remove_assoc_queue(bh);
770
771
772 smp_mb();
773 if (buffer_dirty(bh) || buffer_locked(bh)) {
774 list_add(&bh->b_assoc_buffers, &tmp);
775 bh->b_assoc_map = mapping;
776 if (buffer_dirty(bh)) {
777 get_bh(bh);
778 spin_unlock(lock);
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780
781
782
783
784
785 ll_rw_block(SWRITE_SYNC_PLUG, 1, &bh);
786
787
788
789
790
791
792
793 if (prev_mapping && prev_mapping != mapping)
794 blk_run_address_space(prev_mapping);
795 prev_mapping = mapping;
796
797 brelse(bh);
798 spin_lock(lock);
799 }
800 }
801 }
802
803 while (!list_empty(&tmp)) {
804 bh = BH_ENTRY(tmp.prev);
805 get_bh(bh);
806 mapping = bh->b_assoc_map;
807 __remove_assoc_queue(bh);
808
809
810 smp_mb();
811 if (buffer_dirty(bh)) {
812 list_add(&bh->b_assoc_buffers,
813 &mapping->private_list);
814 bh->b_assoc_map = mapping;
815 }
816 spin_unlock(lock);
817 wait_on_buffer(bh);
818 if (!buffer_uptodate(bh))
819 err = -EIO;
820 brelse(bh);
821 spin_lock(lock);
822 }
823
824 spin_unlock(lock);
825 err2 = osync_buffers_list(lock, list);
826 if (err)
827 return err;
828 else
829 return err2;
830}
831
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839
840
841void invalidate_inode_buffers(struct inode *inode)
842{
843 if (inode_has_buffers(inode)) {
844 struct address_space *mapping = &inode->i_data;
845 struct list_head *list = &mapping->private_list;
846 struct address_space *buffer_mapping = mapping->assoc_mapping;
847
848 spin_lock(&buffer_mapping->private_lock);
849 while (!list_empty(list))
850 __remove_assoc_queue(BH_ENTRY(list->next));
851 spin_unlock(&buffer_mapping->private_lock);
852 }
853}
854EXPORT_SYMBOL(invalidate_inode_buffers);
855
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860
861
862int remove_inode_buffers(struct inode *inode)
863{
864 int ret = 1;
865
866 if (inode_has_buffers(inode)) {
867 struct address_space *mapping = &inode->i_data;
868 struct list_head *list = &mapping->private_list;
869 struct address_space *buffer_mapping = mapping->assoc_mapping;
870
871 spin_lock(&buffer_mapping->private_lock);
872 while (!list_empty(list)) {
873 struct buffer_head *bh = BH_ENTRY(list->next);
874 if (buffer_dirty(bh)) {
875 ret = 0;
876 break;
877 }
878 __remove_assoc_queue(bh);
879 }
880 spin_unlock(&buffer_mapping->private_lock);
881 }
882 return ret;
883}
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893
894struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
895 int retry)
896{
897 struct buffer_head *bh, *head;
898 long offset;
899
900try_again:
901 head = NULL;
902 offset = PAGE_SIZE;
903 while ((offset -= size) >= 0) {
904 bh = alloc_buffer_head(GFP_NOFS);
905 if (!bh)
906 goto no_grow;
907
908 bh->b_bdev = NULL;
909 bh->b_this_page = head;
910 bh->b_blocknr = -1;
911 head = bh;
912
913 bh->b_state = 0;
914 atomic_set(&bh->b_count, 0);
915 bh->b_private = NULL;
916 bh->b_size = size;
917
918
919 set_bh_page(bh, page, offset);
920
921 init_buffer(bh, NULL, NULL);
922 }
923 return head;
924
925
926
927no_grow:
928 if (head) {
929 do {
930 bh = head;
931 head = head->b_this_page;
932 free_buffer_head(bh);
933 } while (head);
934 }
935
936
937
938
939
940
941
942 if (!retry)
943 return NULL;
944
945
946
947
948
949
950
951 free_more_memory();
952 goto try_again;
953}
954EXPORT_SYMBOL_GPL(alloc_page_buffers);
955
956static inline void
957link_dev_buffers(struct page *page, struct buffer_head *head)
958{
959 struct buffer_head *bh, *tail;
960
961 bh = head;
962 do {
963 tail = bh;
964 bh = bh->b_this_page;
965 } while (bh);
966 tail->b_this_page = head;
967 attach_page_buffers(page, head);
968}
969
970
971
972
973static void
974init_page_buffers(struct page *page, struct block_device *bdev,
975 sector_t block, int size)
976{
977 struct buffer_head *head = page_buffers(page);
978 struct buffer_head *bh = head;
979 int uptodate = PageUptodate(page);
980
981 do {
982 if (!buffer_mapped(bh)) {
983 init_buffer(bh, NULL, NULL);
984 bh->b_bdev = bdev;
985 bh->b_blocknr = block;
986 if (uptodate)
987 set_buffer_uptodate(bh);
988 set_buffer_mapped(bh);
989 }
990 block++;
991 bh = bh->b_this_page;
992 } while (bh != head);
993}
994
995
996
997
998
999
1000static struct page *
1001grow_dev_page(struct block_device *bdev, sector_t block,
1002 pgoff_t index, int size)
1003{
1004 struct inode *inode = bdev->bd_inode;
1005 struct page *page;
1006 struct buffer_head *bh;
1007
1008 page = find_or_create_page(inode->i_mapping, index,
1009 (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE);
1010 if (!page)
1011 return NULL;
1012
1013 BUG_ON(!PageLocked(page));
1014
1015 if (page_has_buffers(page)) {
1016 bh = page_buffers(page);
1017 if (bh->b_size == size) {
1018 init_page_buffers(page, bdev, block, size);
1019 return page;
1020 }
1021 if (!try_to_free_buffers(page))
1022 goto failed;
1023 }
1024
1025
1026
1027
1028 bh = alloc_page_buffers(page, size, 0);
1029 if (!bh)
1030 goto failed;
1031
1032
1033
1034
1035
1036
1037 spin_lock(&inode->i_mapping->private_lock);
1038 link_dev_buffers(page, bh);
1039 init_page_buffers(page, bdev, block, size);
1040 spin_unlock(&inode->i_mapping->private_lock);
1041 return page;
1042
1043failed:
1044 BUG();
1045 unlock_page(page);
1046 page_cache_release(page);
1047 return NULL;
1048}
1049
1050
1051
1052
1053
1054static int
1055grow_buffers(struct block_device *bdev, sector_t block, int size)
1056{
1057 struct page *page;
1058 pgoff_t index;
1059 int sizebits;
1060
1061 sizebits = -1;
1062 do {
1063 sizebits++;
1064 } while ((size << sizebits) < PAGE_SIZE);
1065
1066 index = block >> sizebits;
1067
1068
1069
1070
1071
1072 if (unlikely(index != block >> sizebits)) {
1073 char b[BDEVNAME_SIZE];
1074
1075 printk(KERN_ERR "%s: requested out-of-range block %llu for "
1076 "device %s\n",
1077 __func__, (unsigned long long)block,
1078 bdevname(bdev, b));
1079 return -EIO;
1080 }
1081 block = index << sizebits;
1082
1083 page = grow_dev_page(bdev, block, index, size);
1084 if (!page)
1085 return 0;
1086 unlock_page(page);
1087 page_cache_release(page);
1088 return 1;
1089}
1090
1091static struct buffer_head *
1092__getblk_slow(struct block_device *bdev, sector_t block, int size)
1093{
1094
1095 if (unlikely(size & (bdev_logical_block_size(bdev)-1) ||
1096 (size < 512 || size > PAGE_SIZE))) {
1097 printk(KERN_ERR "getblk(): invalid block size %d requested\n",
1098 size);
1099 printk(KERN_ERR "logical block size: %d\n",
1100 bdev_logical_block_size(bdev));
1101
1102 dump_stack();
1103 return NULL;
1104 }
1105
1106 for (;;) {
1107 struct buffer_head * bh;
1108 int ret;
1109
1110 bh = __find_get_block(bdev, block, size);
1111 if (bh)
1112 return bh;
1113
1114 ret = grow_buffers(bdev, block, size);
1115 if (ret < 0)
1116 return NULL;
1117 if (ret == 0)
1118 free_more_memory();
1119 }
1120}
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157void mark_buffer_dirty(struct buffer_head *bh)
1158{
1159 WARN_ON_ONCE(!buffer_uptodate(bh));
1160
1161
1162
1163
1164
1165
1166
1167 if (buffer_dirty(bh)) {
1168 smp_mb();
1169 if (buffer_dirty(bh))
1170 return;
1171 }
1172
1173 if (!test_set_buffer_dirty(bh)) {
1174 struct page *page = bh->b_page;
1175 if (!TestSetPageDirty(page)) {
1176 struct address_space *mapping = page_mapping(page);
1177 if (mapping)
1178 __set_page_dirty(page, mapping, 0);
1179 }
1180 }
1181}
1182EXPORT_SYMBOL(mark_buffer_dirty);
1183
1184
1185
1186
1187
1188
1189
1190
1191void __brelse(struct buffer_head * buf)
1192{
1193 if (atomic_read(&buf->b_count)) {
1194 put_bh(buf);
1195 return;
1196 }
1197 WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n");
1198}
1199EXPORT_SYMBOL(__brelse);
1200
1201
1202
1203
1204
1205void __bforget(struct buffer_head *bh)
1206{
1207 clear_buffer_dirty(bh);
1208 if (bh->b_assoc_map) {
1209 struct address_space *buffer_mapping = bh->b_page->mapping;
1210
1211 spin_lock(&buffer_mapping->private_lock);
1212 list_del_init(&bh->b_assoc_buffers);
1213 bh->b_assoc_map = NULL;
1214 spin_unlock(&buffer_mapping->private_lock);
1215 }
1216 __brelse(bh);
1217}
1218EXPORT_SYMBOL(__bforget);
1219
1220static struct buffer_head *__bread_slow(struct buffer_head *bh)
1221{
1222 lock_buffer(bh);
1223 if (buffer_uptodate(bh)) {
1224 unlock_buffer(bh);
1225 return bh;
1226 } else {
1227 get_bh(bh);
1228 bh->b_end_io = end_buffer_read_sync;
1229 submit_bh(READ, bh);
1230 wait_on_buffer(bh);
1231 if (buffer_uptodate(bh))
1232 return bh;
1233 }
1234 brelse(bh);
1235 return NULL;
1236}
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252#define BH_LRU_SIZE 8
1253
1254struct bh_lru {
1255 struct buffer_head *bhs[BH_LRU_SIZE];
1256};
1257
1258static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }};
1259
1260#ifdef CONFIG_SMP
1261#define bh_lru_lock() local_irq_disable()
1262#define bh_lru_unlock() local_irq_enable()
1263#else
1264#define bh_lru_lock() preempt_disable()
1265#define bh_lru_unlock() preempt_enable()
1266#endif
1267
1268static inline void check_irqs_on(void)
1269{
1270#ifdef irqs_disabled
1271 BUG_ON(irqs_disabled());
1272#endif
1273}
1274
1275
1276
1277
1278static void bh_lru_install(struct buffer_head *bh)
1279{
1280 struct buffer_head *evictee = NULL;
1281 struct bh_lru *lru;
1282
1283 check_irqs_on();
1284 bh_lru_lock();
1285 lru = &__get_cpu_var(bh_lrus);
1286 if (lru->bhs[0] != bh) {
1287 struct buffer_head *bhs[BH_LRU_SIZE];
1288 int in;
1289 int out = 0;
1290
1291 get_bh(bh);
1292 bhs[out++] = bh;
1293 for (in = 0; in < BH_LRU_SIZE; in++) {
1294 struct buffer_head *bh2 = lru->bhs[in];
1295
1296 if (bh2 == bh) {
1297 __brelse(bh2);
1298 } else {
1299 if (out >= BH_LRU_SIZE) {
1300 BUG_ON(evictee != NULL);
1301 evictee = bh2;
1302 } else {
1303 bhs[out++] = bh2;
1304 }
1305 }
1306 }
1307 while (out < BH_LRU_SIZE)
1308 bhs[out++] = NULL;
1309 memcpy(lru->bhs, bhs, sizeof(bhs));
1310 }
1311 bh_lru_unlock();
1312
1313 if (evictee)
1314 __brelse(evictee);
1315}
1316
1317
1318
1319
1320static struct buffer_head *
1321lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size)
1322{
1323 struct buffer_head *ret = NULL;
1324 struct bh_lru *lru;
1325 unsigned int i;
1326
1327 check_irqs_on();
1328 bh_lru_lock();
1329 lru = &__get_cpu_var(bh_lrus);
1330 for (i = 0; i < BH_LRU_SIZE; i++) {
1331 struct buffer_head *bh = lru->bhs[i];
1332
1333 if (bh && bh->b_bdev == bdev &&
1334 bh->b_blocknr == block && bh->b_size == size) {
1335 if (i) {
1336 while (i) {
1337 lru->bhs[i] = lru->bhs[i - 1];
1338 i--;
1339 }
1340 lru->bhs[0] = bh;
1341 }
1342 get_bh(bh);
1343 ret = bh;
1344 break;
1345 }
1346 }
1347 bh_lru_unlock();
1348 return ret;
1349}
1350
1351
1352
1353
1354
1355
1356struct buffer_head *
1357__find_get_block(struct block_device *bdev, sector_t block, unsigned size)
1358{
1359 struct buffer_head *bh = lookup_bh_lru(bdev, block, size);
1360
1361 if (bh == NULL) {
1362 bh = __find_get_block_slow(bdev, block);
1363 if (bh)
1364 bh_lru_install(bh);
1365 }
1366 if (bh)
1367 touch_buffer(bh);
1368 return bh;
1369}
1370EXPORT_SYMBOL(__find_get_block);
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384struct buffer_head *
1385__getblk(struct block_device *bdev, sector_t block, unsigned size)
1386{
1387 struct buffer_head *bh = __find_get_block(bdev, block, size);
1388
1389 might_sleep();
1390 if (bh == NULL)
1391 bh = __getblk_slow(bdev, block, size);
1392 return bh;
1393}
1394EXPORT_SYMBOL(__getblk);
1395
1396
1397
1398
1399void __breadahead(struct block_device *bdev, sector_t block, unsigned size)
1400{
1401 struct buffer_head *bh = __getblk(bdev, block, size);
1402 if (likely(bh)) {
1403 ll_rw_block(READA, 1, &bh);
1404 brelse(bh);
1405 }
1406}
1407EXPORT_SYMBOL(__breadahead);
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418struct buffer_head *
1419__bread(struct block_device *bdev, sector_t block, unsigned size)
1420{
1421 struct buffer_head *bh = __getblk(bdev, block, size);
1422
1423 if (likely(bh) && !buffer_uptodate(bh))
1424 bh = __bread_slow(bh);
1425 return bh;
1426}
1427EXPORT_SYMBOL(__bread);
1428
1429
1430
1431
1432
1433
1434static void invalidate_bh_lru(void *arg)
1435{
1436 struct bh_lru *b = &get_cpu_var(bh_lrus);
1437 int i;
1438
1439 for (i = 0; i < BH_LRU_SIZE; i++) {
1440 brelse(b->bhs[i]);
1441 b->bhs[i] = NULL;
1442 }
1443 put_cpu_var(bh_lrus);
1444}
1445
1446void invalidate_bh_lrus(void)
1447{
1448 on_each_cpu(invalidate_bh_lru, NULL, 1);
1449}
1450EXPORT_SYMBOL_GPL(invalidate_bh_lrus);
1451
1452void set_bh_page(struct buffer_head *bh,
1453 struct page *page, unsigned long offset)
1454{
1455 bh->b_page = page;
1456 BUG_ON(offset >= PAGE_SIZE);
1457 if (PageHighMem(page))
1458
1459
1460
1461 bh->b_data = (char *)(0 + offset);
1462 else
1463 bh->b_data = page_address(page) + offset;
1464}
1465EXPORT_SYMBOL(set_bh_page);
1466
1467
1468
1469
1470static void discard_buffer(struct buffer_head * bh)
1471{
1472 lock_buffer(bh);
1473 clear_buffer_dirty(bh);
1474 bh->b_bdev = NULL;
1475 clear_buffer_mapped(bh);
1476 clear_buffer_req(bh);
1477 clear_buffer_new(bh);
1478 clear_buffer_delay(bh);
1479 clear_buffer_unwritten(bh);
1480 unlock_buffer(bh);
1481}
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498void block_invalidatepage(struct page *page, unsigned long offset)
1499{
1500 struct buffer_head *head, *bh, *next;
1501 unsigned int curr_off = 0;
1502
1503 BUG_ON(!PageLocked(page));
1504 if (!page_has_buffers(page))
1505 goto out;
1506
1507 head = page_buffers(page);
1508 bh = head;
1509 do {
1510 unsigned int next_off = curr_off + bh->b_size;
1511 next = bh->b_this_page;
1512
1513
1514
1515
1516 if (offset <= curr_off)
1517 discard_buffer(bh);
1518 curr_off = next_off;
1519 bh = next;
1520 } while (bh != head);
1521
1522
1523
1524
1525
1526
1527 if (offset == 0)
1528 try_to_release_page(page, 0);
1529out:
1530 return;
1531}
1532EXPORT_SYMBOL(block_invalidatepage);
1533
1534
1535
1536
1537
1538
1539void create_empty_buffers(struct page *page,
1540 unsigned long blocksize, unsigned long b_state)
1541{
1542 struct buffer_head *bh, *head, *tail;
1543
1544 head = alloc_page_buffers(page, blocksize, 1);
1545 bh = head;
1546 do {
1547 bh->b_state |= b_state;
1548 tail = bh;
1549 bh = bh->b_this_page;
1550 } while (bh);
1551 tail->b_this_page = head;
1552
1553 spin_lock(&page->mapping->private_lock);
1554 if (PageUptodate(page) || PageDirty(page)) {
1555 bh = head;
1556 do {
1557 if (PageDirty(page))
1558 set_buffer_dirty(bh);
1559 if (PageUptodate(page))
1560 set_buffer_uptodate(bh);
1561 bh = bh->b_this_page;
1562 } while (bh != head);
1563 }
1564 attach_page_buffers(page, head);
1565 spin_unlock(&page->mapping->private_lock);
1566}
1567EXPORT_SYMBOL(create_empty_buffers);
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585void unmap_underlying_metadata(struct block_device *bdev, sector_t block)
1586{
1587 struct buffer_head *old_bh;
1588
1589 might_sleep();
1590
1591 old_bh = __find_get_block_slow(bdev, block);
1592 if (old_bh) {
1593 clear_buffer_dirty(old_bh);
1594 wait_on_buffer(old_bh);
1595 clear_buffer_req(old_bh);
1596 __brelse(old_bh);
1597 }
1598}
1599EXPORT_SYMBOL(unmap_underlying_metadata);
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636static int __block_write_full_page(struct inode *inode, struct page *page,
1637 get_block_t *get_block, struct writeback_control *wbc,
1638 bh_end_io_t *handler)
1639{
1640 int err;
1641 sector_t block;
1642 sector_t last_block;
1643 struct buffer_head *bh, *head;
1644 const unsigned blocksize = 1 << inode->i_blkbits;
1645 int nr_underway = 0;
1646 int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
1647 WRITE_SYNC_PLUG : WRITE);
1648
1649 BUG_ON(!PageLocked(page));
1650
1651 last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
1652
1653 if (!page_has_buffers(page)) {
1654 create_empty_buffers(page, blocksize,
1655 (1 << BH_Dirty)|(1 << BH_Uptodate));
1656 }
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668 block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1669 head = page_buffers(page);
1670 bh = head;
1671
1672
1673
1674
1675
1676 do {
1677 if (block > last_block) {
1678
1679
1680
1681
1682
1683
1684
1685
1686 clear_buffer_dirty(bh);
1687 set_buffer_uptodate(bh);
1688 } else if ((!buffer_mapped(bh) || buffer_delay(bh)) &&
1689 buffer_dirty(bh)) {
1690 WARN_ON(bh->b_size != blocksize);
1691 err = get_block(inode, block, bh, 1);
1692 if (err)
1693 goto recover;
1694 clear_buffer_delay(bh);
1695 if (buffer_new(bh)) {
1696
1697 clear_buffer_new(bh);
1698 unmap_underlying_metadata(bh->b_bdev,
1699 bh->b_blocknr);
1700 }
1701 }
1702 bh = bh->b_this_page;
1703 block++;
1704 } while (bh != head);
1705
1706 do {
1707 if (!buffer_mapped(bh))
1708 continue;
1709
1710
1711
1712
1713
1714
1715
1716 if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
1717 lock_buffer(bh);
1718 } else if (!trylock_buffer(bh)) {
1719 redirty_page_for_writepage(wbc, page);
1720 continue;
1721 }
1722 if (test_clear_buffer_dirty(bh)) {
1723 mark_buffer_async_write_endio(bh, handler);
1724 } else {
1725 unlock_buffer(bh);
1726 }
1727 } while ((bh = bh->b_this_page) != head);
1728
1729
1730
1731
1732
1733 BUG_ON(PageWriteback(page));
1734 set_page_writeback(page);
1735
1736 do {
1737 struct buffer_head *next = bh->b_this_page;
1738 if (buffer_async_write(bh)) {
1739 submit_bh(write_op, bh);
1740 nr_underway++;
1741 }
1742 bh = next;
1743 } while (bh != head);
1744 unlock_page(page);
1745
1746 err = 0;
1747done:
1748 if (nr_underway == 0) {
1749
1750
1751
1752
1753
1754 end_page_writeback(page);
1755
1756
1757
1758
1759
1760 }
1761 return err;
1762
1763recover:
1764
1765
1766
1767
1768
1769
1770 bh = head;
1771
1772 do {
1773 if (buffer_mapped(bh) && buffer_dirty(bh) &&
1774 !buffer_delay(bh)) {
1775 lock_buffer(bh);
1776 mark_buffer_async_write_endio(bh, handler);
1777 } else {
1778
1779
1780
1781
1782 clear_buffer_dirty(bh);
1783 }
1784 } while ((bh = bh->b_this_page) != head);
1785 SetPageError(page);
1786 BUG_ON(PageWriteback(page));
1787 mapping_set_error(page->mapping, err);
1788 set_page_writeback(page);
1789 do {
1790 struct buffer_head *next = bh->b_this_page;
1791 if (buffer_async_write(bh)) {
1792 clear_buffer_dirty(bh);
1793 submit_bh(write_op, bh);
1794 nr_underway++;
1795 }
1796 bh = next;
1797 } while (bh != head);
1798 unlock_page(page);
1799 goto done;
1800}
1801
1802
1803
1804
1805
1806
1807void page_zero_new_buffers(struct page *page, unsigned from, unsigned to)
1808{
1809 unsigned int block_start, block_end;
1810 struct buffer_head *head, *bh;
1811
1812 BUG_ON(!PageLocked(page));
1813 if (!page_has_buffers(page))
1814 return;
1815
1816 bh = head = page_buffers(page);
1817 block_start = 0;
1818 do {
1819 block_end = block_start + bh->b_size;
1820
1821 if (buffer_new(bh)) {
1822 if (block_end > from && block_start < to) {
1823 if (!PageUptodate(page)) {
1824 unsigned start, size;
1825
1826 start = max(from, block_start);
1827 size = min(to, block_end) - start;
1828
1829 zero_user(page, start, size);
1830 set_buffer_uptodate(bh);
1831 }
1832
1833 clear_buffer_new(bh);
1834 mark_buffer_dirty(bh);
1835 }
1836 }
1837
1838 block_start = block_end;
1839 bh = bh->b_this_page;
1840 } while (bh != head);
1841}
1842EXPORT_SYMBOL(page_zero_new_buffers);
1843
1844static int __block_prepare_write(struct inode *inode, struct page *page,
1845 unsigned from, unsigned to, get_block_t *get_block)
1846{
1847 unsigned block_start, block_end;
1848 sector_t block;
1849 int err = 0;
1850 unsigned blocksize, bbits;
1851 struct buffer_head *bh, *head, *wait[2], **wait_bh=wait;
1852
1853 BUG_ON(!PageLocked(page));
1854 BUG_ON(from > PAGE_CACHE_SIZE);
1855 BUG_ON(to > PAGE_CACHE_SIZE);
1856 BUG_ON(from > to);
1857
1858 blocksize = 1 << inode->i_blkbits;
1859 if (!page_has_buffers(page))
1860 create_empty_buffers(page, blocksize, 0);
1861 head = page_buffers(page);
1862
1863 bbits = inode->i_blkbits;
1864 block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
1865
1866 for(bh = head, block_start = 0; bh != head || !block_start;
1867 block++, block_start=block_end, bh = bh->b_this_page) {
1868 block_end = block_start + blocksize;
1869 if (block_end <= from || block_start >= to) {
1870 if (PageUptodate(page)) {
1871 if (!buffer_uptodate(bh))
1872 set_buffer_uptodate(bh);
1873 }
1874 continue;
1875 }
1876 if (buffer_new(bh))
1877 clear_buffer_new(bh);
1878 if (!buffer_mapped(bh)) {
1879 WARN_ON(bh->b_size != blocksize);
1880 err = get_block(inode, block, bh, 1);
1881 if (err)
1882 break;
1883 if (buffer_new(bh)) {
1884 unmap_underlying_metadata(bh->b_bdev,
1885 bh->b_blocknr);
1886 if (PageUptodate(page)) {
1887 clear_buffer_new(bh);
1888 set_buffer_uptodate(bh);
1889 mark_buffer_dirty(bh);
1890 continue;
1891 }
1892 if (block_end > to || block_start < from)
1893 zero_user_segments(page,
1894 to, block_end,
1895 block_start, from);
1896 continue;
1897 }
1898 }
1899 if (PageUptodate(page)) {
1900 if (!buffer_uptodate(bh))
1901 set_buffer_uptodate(bh);
1902 continue;
1903 }
1904 if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1905 !buffer_unwritten(bh) &&
1906 (block_start < from || block_end > to)) {
1907 ll_rw_block(READ, 1, &bh);
1908 *wait_bh++=bh;
1909 }
1910 }
1911
1912
1913
1914 while(wait_bh > wait) {
1915 wait_on_buffer(*--wait_bh);
1916 if (!buffer_uptodate(*wait_bh))
1917 err = -EIO;
1918 }
1919 if (unlikely(err))
1920 page_zero_new_buffers(page, from, to);
1921 return err;
1922}
1923
1924static int __block_commit_write(struct inode *inode, struct page *page,
1925 unsigned from, unsigned to)
1926{
1927 unsigned block_start, block_end;
1928 int partial = 0;
1929 unsigned blocksize;
1930 struct buffer_head *bh, *head;
1931
1932 blocksize = 1 << inode->i_blkbits;
1933
1934 for(bh = head = page_buffers(page), block_start = 0;
1935 bh != head || !block_start;
1936 block_start=block_end, bh = bh->b_this_page) {
1937 block_end = block_start + blocksize;
1938 if (block_end <= from || block_start >= to) {
1939 if (!buffer_uptodate(bh))
1940 partial = 1;
1941 } else {
1942 set_buffer_uptodate(bh);
1943 mark_buffer_dirty(bh);
1944 }
1945 clear_buffer_new(bh);
1946 }
1947
1948
1949
1950
1951
1952
1953
1954 if (!partial)
1955 SetPageUptodate(page);
1956 return 0;
1957}
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967int block_write_begin(struct file *file, struct address_space *mapping,
1968 loff_t pos, unsigned len, unsigned flags,
1969 struct page **pagep, void **fsdata,
1970 get_block_t *get_block)
1971{
1972 struct inode *inode = mapping->host;
1973 int status = 0;
1974 struct page *page;
1975 pgoff_t index;
1976 unsigned start, end;
1977 int ownpage = 0;
1978
1979 index = pos >> PAGE_CACHE_SHIFT;
1980 start = pos & (PAGE_CACHE_SIZE - 1);
1981 end = start + len;
1982
1983 page = *pagep;
1984 if (page == NULL) {
1985 ownpage = 1;
1986 page = grab_cache_page_write_begin(mapping, index, flags);
1987 if (!page) {
1988 status = -ENOMEM;
1989 goto out;
1990 }
1991 *pagep = page;
1992 } else
1993 BUG_ON(!PageLocked(page));
1994
1995 status = __block_prepare_write(inode, page, start, end, get_block);
1996 if (unlikely(status)) {
1997 ClearPageUptodate(page);
1998
1999 if (ownpage) {
2000 unlock_page(page);
2001 page_cache_release(page);
2002 *pagep = NULL;
2003
2004
2005
2006
2007
2008
2009 if (pos + len > inode->i_size)
2010 vmtruncate(inode, inode->i_size);
2011 }
2012 }
2013
2014out:
2015 return status;
2016}
2017EXPORT_SYMBOL(block_write_begin);
2018
2019int block_write_end(struct file *file, struct address_space *mapping,
2020 loff_t pos, unsigned len, unsigned copied,
2021 struct page *page, void *fsdata)
2022{
2023 struct inode *inode = mapping->host;
2024 unsigned start;
2025
2026 start = pos & (PAGE_CACHE_SIZE - 1);
2027
2028 if (unlikely(copied < len)) {
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041 if (!PageUptodate(page))
2042 copied = 0;
2043
2044 page_zero_new_buffers(page, start+copied, start+len);
2045 }
2046 flush_dcache_page(page);
2047
2048
2049 __block_commit_write(inode, page, start, start+copied);
2050
2051 return copied;
2052}
2053EXPORT_SYMBOL(block_write_end);
2054
2055int generic_write_end(struct file *file, struct address_space *mapping,
2056 loff_t pos, unsigned len, unsigned copied,
2057 struct page *page, void *fsdata)
2058{
2059 struct inode *inode = mapping->host;
2060 int i_size_changed = 0;
2061
2062 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
2063
2064
2065
2066
2067
2068
2069
2070
2071 if (pos+copied > inode->i_size) {
2072 i_size_write(inode, pos+copied);
2073 i_size_changed = 1;
2074 }
2075
2076 unlock_page(page);
2077 page_cache_release(page);
2078
2079
2080
2081
2082
2083
2084
2085 if (i_size_changed)
2086 mark_inode_dirty(inode);
2087
2088 return copied;
2089}
2090EXPORT_SYMBOL(generic_write_end);
2091
2092
2093
2094
2095
2096
2097
2098
2099int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
2100 unsigned long from)
2101{
2102 struct inode *inode = page->mapping->host;
2103 unsigned block_start, block_end, blocksize;
2104 unsigned to;
2105 struct buffer_head *bh, *head;
2106 int ret = 1;
2107
2108 if (!page_has_buffers(page))
2109 return 0;
2110
2111 blocksize = 1 << inode->i_blkbits;
2112 to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count);
2113 to = from + to;
2114 if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize)
2115 return 0;
2116
2117 head = page_buffers(page);
2118 bh = head;
2119 block_start = 0;
2120 do {
2121 block_end = block_start + blocksize;
2122 if (block_end > from && block_start < to) {
2123 if (!buffer_uptodate(bh)) {
2124 ret = 0;
2125 break;
2126 }
2127 if (block_end >= to)
2128 break;
2129 }
2130 block_start = block_end;
2131 bh = bh->b_this_page;
2132 } while (bh != head);
2133
2134 return ret;
2135}
2136EXPORT_SYMBOL(block_is_partially_uptodate);
2137
2138
2139
2140
2141
2142
2143
2144
2145int block_read_full_page(struct page *page, get_block_t *get_block)
2146{
2147 struct inode *inode = page->mapping->host;
2148 sector_t iblock, lblock;
2149 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
2150 unsigned int blocksize;
2151 int nr, i;
2152 int fully_mapped = 1;
2153
2154 BUG_ON(!PageLocked(page));
2155 blocksize = 1 << inode->i_blkbits;
2156 if (!page_has_buffers(page))
2157 create_empty_buffers(page, blocksize, 0);
2158 head = page_buffers(page);
2159
2160 iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
2161 lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits;
2162 bh = head;
2163 nr = 0;
2164 i = 0;
2165
2166 do {
2167 if (buffer_uptodate(bh))
2168 continue;
2169
2170 if (!buffer_mapped(bh)) {
2171 int err = 0;
2172
2173 fully_mapped = 0;
2174 if (iblock < lblock) {
2175 WARN_ON(bh->b_size != blocksize);
2176 err = get_block(inode, iblock, bh, 0);
2177 if (err)
2178 SetPageError(page);
2179 }
2180 if (!buffer_mapped(bh)) {
2181 zero_user(page, i * blocksize, blocksize);
2182 if (!err)
2183 set_buffer_uptodate(bh);
2184 continue;
2185 }
2186
2187
2188
2189
2190 if (buffer_uptodate(bh))
2191 continue;
2192 }
2193 arr[nr++] = bh;
2194 } while (i++, iblock++, (bh = bh->b_this_page) != head);
2195
2196 if (fully_mapped)
2197 SetPageMappedToDisk(page);
2198
2199 if (!nr) {
2200
2201
2202
2203
2204 if (!PageError(page))
2205 SetPageUptodate(page);
2206 unlock_page(page);
2207 return 0;
2208 }
2209
2210
2211 for (i = 0; i < nr; i++) {
2212 bh = arr[i];
2213 lock_buffer(bh);
2214 mark_buffer_async_read(bh);
2215 }
2216
2217
2218
2219
2220
2221
2222 for (i = 0; i < nr; i++) {
2223 bh = arr[i];
2224 if (buffer_uptodate(bh))
2225 end_buffer_async_read(bh, 1);
2226 else
2227 submit_bh(READ, bh);
2228 }
2229 return 0;
2230}
2231EXPORT_SYMBOL(block_read_full_page);
2232
2233
2234
2235
2236
2237int generic_cont_expand_simple(struct inode *inode, loff_t size)
2238{
2239 struct address_space *mapping = inode->i_mapping;
2240 struct page *page;
2241 void *fsdata;
2242 int err;
2243
2244 err = inode_newsize_ok(inode, size);
2245 if (err)
2246 goto out;
2247
2248 err = pagecache_write_begin(NULL, mapping, size, 0,
2249 AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND,
2250 &page, &fsdata);
2251 if (err)
2252 goto out;
2253
2254 err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata);
2255 BUG_ON(err > 0);
2256
2257out:
2258 return err;
2259}
2260EXPORT_SYMBOL(generic_cont_expand_simple);
2261
2262static int cont_expand_zero(struct file *file, struct address_space *mapping,
2263 loff_t pos, loff_t *bytes)
2264{
2265 struct inode *inode = mapping->host;
2266 unsigned blocksize = 1 << inode->i_blkbits;
2267 struct page *page;
2268 void *fsdata;
2269 pgoff_t index, curidx;
2270 loff_t curpos;
2271 unsigned zerofrom, offset, len;
2272 int err = 0;
2273
2274 index = pos >> PAGE_CACHE_SHIFT;
2275 offset = pos & ~PAGE_CACHE_MASK;
2276
2277 while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) {
2278 zerofrom = curpos & ~PAGE_CACHE_MASK;
2279 if (zerofrom & (blocksize-1)) {
2280 *bytes |= (blocksize-1);
2281 (*bytes)++;
2282 }
2283 len = PAGE_CACHE_SIZE - zerofrom;
2284
2285 err = pagecache_write_begin(file, mapping, curpos, len,
2286 AOP_FLAG_UNINTERRUPTIBLE,
2287 &page, &fsdata);
2288 if (err)
2289 goto out;
2290 zero_user(page, zerofrom, len);
2291 err = pagecache_write_end(file, mapping, curpos, len, len,
2292 page, fsdata);
2293 if (err < 0)
2294 goto out;
2295 BUG_ON(err != len);
2296 err = 0;
2297
2298 balance_dirty_pages_ratelimited(mapping);
2299 }
2300
2301
2302 if (index == curidx) {
2303 zerofrom = curpos & ~PAGE_CACHE_MASK;
2304
2305 if (offset <= zerofrom) {
2306 goto out;
2307 }
2308 if (zerofrom & (blocksize-1)) {
2309 *bytes |= (blocksize-1);
2310 (*bytes)++;
2311 }
2312 len = offset - zerofrom;
2313
2314 err = pagecache_write_begin(file, mapping, curpos, len,
2315 AOP_FLAG_UNINTERRUPTIBLE,
2316 &page, &fsdata);
2317 if (err)
2318 goto out;
2319 zero_user(page, zerofrom, len);
2320 err = pagecache_write_end(file, mapping, curpos, len, len,
2321 page, fsdata);
2322 if (err < 0)
2323 goto out;
2324 BUG_ON(err != len);
2325 err = 0;
2326 }
2327out:
2328 return err;
2329}
2330
2331
2332
2333
2334
2335int cont_write_begin(struct file *file, struct address_space *mapping,
2336 loff_t pos, unsigned len, unsigned flags,
2337 struct page **pagep, void **fsdata,
2338 get_block_t *get_block, loff_t *bytes)
2339{
2340 struct inode *inode = mapping->host;
2341 unsigned blocksize = 1 << inode->i_blkbits;
2342 unsigned zerofrom;
2343 int err;
2344
2345 err = cont_expand_zero(file, mapping, pos, bytes);
2346 if (err)
2347 goto out;
2348
2349 zerofrom = *bytes & ~PAGE_CACHE_MASK;
2350 if (pos+len > *bytes && zerofrom & (blocksize-1)) {
2351 *bytes |= (blocksize-1);
2352 (*bytes)++;
2353 }
2354
2355 *pagep = NULL;
2356 err = block_write_begin(file, mapping, pos, len,
2357 flags, pagep, fsdata, get_block);
2358out:
2359 return err;
2360}
2361EXPORT_SYMBOL(cont_write_begin);
2362
2363int block_prepare_write(struct page *page, unsigned from, unsigned to,
2364 get_block_t *get_block)
2365{
2366 struct inode *inode = page->mapping->host;
2367 int err = __block_prepare_write(inode, page, from, to, get_block);
2368 if (err)
2369 ClearPageUptodate(page);
2370 return err;
2371}
2372EXPORT_SYMBOL(block_prepare_write);
2373
2374int block_commit_write(struct page *page, unsigned from, unsigned to)
2375{
2376 struct inode *inode = page->mapping->host;
2377 __block_commit_write(inode,page,from,to);
2378 return 0;
2379}
2380EXPORT_SYMBOL(block_commit_write);
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397int
2398block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
2399 get_block_t get_block)
2400{
2401 struct page *page = vmf->page;
2402 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
2403 unsigned long end;
2404 loff_t size;
2405 int ret = VM_FAULT_NOPAGE;
2406
2407 lock_page(page);
2408 size = i_size_read(inode);
2409 if ((page->mapping != inode->i_mapping) ||
2410 (page_offset(page) > size)) {
2411
2412 unlock_page(page);
2413 goto out;
2414 }
2415
2416
2417 if (((page->index + 1) << PAGE_CACHE_SHIFT) > size)
2418 end = size & ~PAGE_CACHE_MASK;
2419 else
2420 end = PAGE_CACHE_SIZE;
2421
2422 ret = block_prepare_write(page, 0, end, get_block);
2423 if (!ret)
2424 ret = block_commit_write(page, 0, end);
2425
2426 if (unlikely(ret)) {
2427 unlock_page(page);
2428 if (ret == -ENOMEM)
2429 ret = VM_FAULT_OOM;
2430 else
2431 ret = VM_FAULT_SIGBUS;
2432 } else
2433 ret = VM_FAULT_LOCKED;
2434
2435out:
2436 return ret;
2437}
2438EXPORT_SYMBOL(block_page_mkwrite);
2439
2440
2441
2442
2443
2444
2445static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate)
2446{
2447 __end_buffer_read_notouch(bh, uptodate);
2448}
2449
2450
2451
2452
2453
2454
2455static void attach_nobh_buffers(struct page *page, struct buffer_head *head)
2456{
2457 struct buffer_head *bh;
2458
2459 BUG_ON(!PageLocked(page));
2460
2461 spin_lock(&page->mapping->private_lock);
2462 bh = head;
2463 do {
2464 if (PageDirty(page))
2465 set_buffer_dirty(bh);
2466 if (!bh->b_this_page)
2467 bh->b_this_page = head;
2468 bh = bh->b_this_page;
2469 } while (bh != head);
2470 attach_page_buffers(page, head);
2471 spin_unlock(&page->mapping->private_lock);
2472}
2473
2474
2475
2476
2477
2478int nobh_write_begin(struct file *file, struct address_space *mapping,
2479 loff_t pos, unsigned len, unsigned flags,
2480 struct page **pagep, void **fsdata,
2481 get_block_t *get_block)
2482{
2483 struct inode *inode = mapping->host;
2484 const unsigned blkbits = inode->i_blkbits;
2485 const unsigned blocksize = 1 << blkbits;
2486 struct buffer_head *head, *bh;
2487 struct page *page;
2488 pgoff_t index;
2489 unsigned from, to;
2490 unsigned block_in_page;
2491 unsigned block_start, block_end;
2492 sector_t block_in_file;
2493 int nr_reads = 0;
2494 int ret = 0;
2495 int is_mapped_to_disk = 1;
2496
2497 index = pos >> PAGE_CACHE_SHIFT;
2498 from = pos & (PAGE_CACHE_SIZE - 1);
2499 to = from + len;
2500
2501 page = grab_cache_page_write_begin(mapping, index, flags);
2502 if (!page)
2503 return -ENOMEM;
2504 *pagep = page;
2505 *fsdata = NULL;
2506
2507 if (page_has_buffers(page)) {
2508 unlock_page(page);
2509 page_cache_release(page);
2510 *pagep = NULL;
2511 return block_write_begin(file, mapping, pos, len, flags, pagep,
2512 fsdata, get_block);
2513 }
2514
2515 if (PageMappedToDisk(page))
2516 return 0;
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527 head = alloc_page_buffers(page, blocksize, 0);
2528 if (!head) {
2529 ret = -ENOMEM;
2530 goto out_release;
2531 }
2532
2533 block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
2534
2535
2536
2537
2538
2539
2540 for (block_start = 0, block_in_page = 0, bh = head;
2541 block_start < PAGE_CACHE_SIZE;
2542 block_in_page++, block_start += blocksize, bh = bh->b_this_page) {
2543 int create;
2544
2545 block_end = block_start + blocksize;
2546 bh->b_state = 0;
2547 create = 1;
2548 if (block_start >= to)
2549 create = 0;
2550 ret = get_block(inode, block_in_file + block_in_page,
2551 bh, create);
2552 if (ret)
2553 goto failed;
2554 if (!buffer_mapped(bh))
2555 is_mapped_to_disk = 0;
2556 if (buffer_new(bh))
2557 unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
2558 if (PageUptodate(page)) {
2559 set_buffer_uptodate(bh);
2560 continue;
2561 }
2562 if (buffer_new(bh) || !buffer_mapped(bh)) {
2563 zero_user_segments(page, block_start, from,
2564 to, block_end);
2565 continue;
2566 }
2567 if (buffer_uptodate(bh))
2568 continue;
2569 if (block_start < from || block_end > to) {
2570 lock_buffer(bh);
2571 bh->b_end_io = end_buffer_read_nobh;
2572 submit_bh(READ, bh);
2573 nr_reads++;
2574 }
2575 }
2576
2577 if (nr_reads) {
2578
2579
2580
2581
2582
2583 for (bh = head; bh; bh = bh->b_this_page) {
2584 wait_on_buffer(bh);
2585 if (!buffer_uptodate(bh))
2586 ret = -EIO;
2587 }
2588 if (ret)
2589 goto failed;
2590 }
2591
2592 if (is_mapped_to_disk)
2593 SetPageMappedToDisk(page);
2594
2595 *fsdata = head;
2596
2597 return 0;
2598
2599failed:
2600 BUG_ON(!ret);
2601
2602
2603
2604
2605
2606
2607
2608 attach_nobh_buffers(page, head);
2609 page_zero_new_buffers(page, from, to);
2610
2611out_release:
2612 unlock_page(page);
2613 page_cache_release(page);
2614 *pagep = NULL;
2615
2616 if (pos + len > inode->i_size)
2617 vmtruncate(inode, inode->i_size);
2618
2619 return ret;
2620}
2621EXPORT_SYMBOL(nobh_write_begin);
2622
2623int nobh_write_end(struct file *file, struct address_space *mapping,
2624 loff_t pos, unsigned len, unsigned copied,
2625 struct page *page, void *fsdata)
2626{
2627 struct inode *inode = page->mapping->host;
2628 struct buffer_head *head = fsdata;
2629 struct buffer_head *bh;
2630 BUG_ON(fsdata != NULL && page_has_buffers(page));
2631
2632 if (unlikely(copied < len) && head)
2633 attach_nobh_buffers(page, head);
2634 if (page_has_buffers(page))
2635 return generic_write_end(file, mapping, pos, len,
2636 copied, page, fsdata);
2637
2638 SetPageUptodate(page);
2639 set_page_dirty(page);
2640 if (pos+copied > inode->i_size) {
2641 i_size_write(inode, pos+copied);
2642 mark_inode_dirty(inode);
2643 }
2644
2645 unlock_page(page);
2646 page_cache_release(page);
2647
2648 while (head) {
2649 bh = head;
2650 head = head->b_this_page;
2651 free_buffer_head(bh);
2652 }
2653
2654 return copied;
2655}
2656EXPORT_SYMBOL(nobh_write_end);
2657
2658
2659
2660
2661
2662
2663int nobh_writepage(struct page *page, get_block_t *get_block,
2664 struct writeback_control *wbc)
2665{
2666 struct inode * const inode = page->mapping->host;
2667 loff_t i_size = i_size_read(inode);
2668 const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
2669 unsigned offset;
2670 int ret;
2671
2672
2673 if (page->index < end_index)
2674 goto out;
2675
2676
2677 offset = i_size & (PAGE_CACHE_SIZE-1);
2678 if (page->index >= end_index+1 || !offset) {
2679
2680
2681
2682
2683
2684#if 0
2685
2686 if (page->mapping->a_ops->invalidatepage)
2687 page->mapping->a_ops->invalidatepage(page, offset);
2688#endif
2689 unlock_page(page);
2690 return 0;
2691 }
2692
2693
2694
2695
2696
2697
2698
2699
2700 zero_user_segment(page, offset, PAGE_CACHE_SIZE);
2701out:
2702 ret = mpage_writepage(page, get_block, wbc);
2703 if (ret == -EAGAIN)
2704 ret = __block_write_full_page(inode, page, get_block, wbc,
2705 end_buffer_async_write);
2706 return ret;
2707}
2708EXPORT_SYMBOL(nobh_writepage);
2709
2710int nobh_truncate_page(struct address_space *mapping,
2711 loff_t from, get_block_t *get_block)
2712{
2713 pgoff_t index = from >> PAGE_CACHE_SHIFT;
2714 unsigned offset = from & (PAGE_CACHE_SIZE-1);
2715 unsigned blocksize;
2716 sector_t iblock;
2717 unsigned length, pos;
2718 struct inode *inode = mapping->host;
2719 struct page *page;
2720 struct buffer_head map_bh;
2721 int err;
2722
2723 blocksize = 1 << inode->i_blkbits;
2724 length = offset & (blocksize - 1);
2725
2726
2727 if (!length)
2728 return 0;
2729
2730 length = blocksize - length;
2731 iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
2732
2733 page = grab_cache_page(mapping, index);
2734 err = -ENOMEM;
2735 if (!page)
2736 goto out;
2737
2738 if (page_has_buffers(page)) {
2739has_buffers:
2740 unlock_page(page);
2741 page_cache_release(page);
2742 return block_truncate_page(mapping, from, get_block);
2743 }
2744
2745
2746 pos = blocksize;
2747 while (offset >= pos) {
2748 iblock++;
2749 pos += blocksize;
2750 }
2751
2752 map_bh.b_size = blocksize;
2753 map_bh.b_state = 0;
2754 err = get_block(inode, iblock, &map_bh, 0);
2755 if (err)
2756 goto unlock;
2757
2758 if (!buffer_mapped(&map_bh))
2759 goto unlock;
2760
2761
2762 if (!PageUptodate(page)) {
2763 err = mapping->a_ops->readpage(NULL, page);
2764 if (err) {
2765 page_cache_release(page);
2766 goto out;
2767 }
2768 lock_page(page);
2769 if (!PageUptodate(page)) {
2770 err = -EIO;
2771 goto unlock;
2772 }
2773 if (page_has_buffers(page))
2774 goto has_buffers;
2775 }
2776 zero_user(page, offset, length);
2777 set_page_dirty(page);
2778 err = 0;
2779
2780unlock:
2781 unlock_page(page);
2782 page_cache_release(page);
2783out:
2784 return err;
2785}
2786EXPORT_SYMBOL(nobh_truncate_page);
2787
2788int block_truncate_page(struct address_space *mapping,
2789 loff_t from, get_block_t *get_block)
2790{
2791 pgoff_t index = from >> PAGE_CACHE_SHIFT;
2792 unsigned offset = from & (PAGE_CACHE_SIZE-1);
2793 unsigned blocksize;
2794 sector_t iblock;
2795 unsigned length, pos;
2796 struct inode *inode = mapping->host;
2797 struct page *page;
2798 struct buffer_head *bh;
2799 int err;
2800
2801 blocksize = 1 << inode->i_blkbits;
2802 length = offset & (blocksize - 1);
2803
2804
2805 if (!length)
2806 return 0;
2807
2808 length = blocksize - length;
2809 iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
2810
2811 page = grab_cache_page(mapping, index);
2812 err = -ENOMEM;
2813 if (!page)
2814 goto out;
2815
2816 if (!page_has_buffers(page))
2817 create_empty_buffers(page, blocksize, 0);
2818
2819
2820 bh = page_buffers(page);
2821 pos = blocksize;
2822 while (offset >= pos) {
2823 bh = bh->b_this_page;
2824 iblock++;
2825 pos += blocksize;
2826 }
2827
2828 err = 0;
2829 if (!buffer_mapped(bh)) {
2830 WARN_ON(bh->b_size != blocksize);
2831 err = get_block(inode, iblock, bh, 0);
2832 if (err)
2833 goto unlock;
2834
2835 if (!buffer_mapped(bh))
2836 goto unlock;
2837 }
2838
2839
2840 if (PageUptodate(page))
2841 set_buffer_uptodate(bh);
2842
2843 if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) {
2844 err = -EIO;
2845 ll_rw_block(READ, 1, &bh);
2846 wait_on_buffer(bh);
2847
2848 if (!buffer_uptodate(bh))
2849 goto unlock;
2850 }
2851
2852 zero_user(page, offset, length);
2853 mark_buffer_dirty(bh);
2854 err = 0;
2855
2856unlock:
2857 unlock_page(page);
2858 page_cache_release(page);
2859out:
2860 return err;
2861}
2862EXPORT_SYMBOL(block_truncate_page);
2863
2864
2865
2866
2867
2868int block_write_full_page_endio(struct page *page, get_block_t *get_block,
2869 struct writeback_control *wbc, bh_end_io_t *handler)
2870{
2871 struct inode * const inode = page->mapping->host;
2872 loff_t i_size = i_size_read(inode);
2873 const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
2874 unsigned offset;
2875
2876
2877 if (page->index < end_index)
2878 return __block_write_full_page(inode, page, get_block, wbc,
2879 handler);
2880
2881
2882 offset = i_size & (PAGE_CACHE_SIZE-1);
2883 if (page->index >= end_index+1 || !offset) {
2884
2885
2886
2887
2888
2889 do_invalidatepage(page, 0);
2890 unlock_page(page);
2891 return 0;
2892 }
2893
2894
2895
2896
2897
2898
2899
2900
2901 zero_user_segment(page, offset, PAGE_CACHE_SIZE);
2902 return __block_write_full_page(inode, page, get_block, wbc, handler);
2903}
2904EXPORT_SYMBOL(block_write_full_page_endio);
2905
2906
2907
2908
2909int block_write_full_page(struct page *page, get_block_t *get_block,
2910 struct writeback_control *wbc)
2911{
2912 return block_write_full_page_endio(page, get_block, wbc,
2913 end_buffer_async_write);
2914}
2915EXPORT_SYMBOL(block_write_full_page);
2916
2917sector_t generic_block_bmap(struct address_space *mapping, sector_t block,
2918 get_block_t *get_block)
2919{
2920 struct buffer_head tmp;
2921 struct inode *inode = mapping->host;
2922 tmp.b_state = 0;
2923 tmp.b_blocknr = 0;
2924 tmp.b_size = 1 << inode->i_blkbits;
2925 get_block(inode, block, &tmp, 0);
2926 return tmp.b_blocknr;
2927}
2928EXPORT_SYMBOL(generic_block_bmap);
2929
2930static void end_bio_bh_io_sync(struct bio *bio, int err)
2931{
2932 struct buffer_head *bh = bio->bi_private;
2933
2934 if (err == -EOPNOTSUPP) {
2935 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
2936 set_bit(BH_Eopnotsupp, &bh->b_state);
2937 }
2938
2939 if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags)))
2940 set_bit(BH_Quiet, &bh->b_state);
2941
2942 bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags));
2943 bio_put(bio);
2944}
2945
2946int submit_bh(int rw, struct buffer_head * bh)
2947{
2948 struct bio *bio;
2949 int ret = 0;
2950
2951 BUG_ON(!buffer_locked(bh));
2952 BUG_ON(!buffer_mapped(bh));
2953 BUG_ON(!bh->b_end_io);
2954 BUG_ON(buffer_delay(bh));
2955 BUG_ON(buffer_unwritten(bh));
2956
2957
2958
2959
2960
2961 if (buffer_ordered(bh) && (rw & WRITE))
2962 rw |= WRITE_BARRIER;
2963
2964
2965
2966
2967 if (test_set_buffer_req(bh) && (rw & WRITE))
2968 clear_buffer_write_io_error(bh);
2969
2970
2971
2972
2973
2974 bio = bio_alloc(GFP_NOIO, 1);
2975
2976 bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
2977 bio->bi_bdev = bh->b_bdev;
2978 bio->bi_io_vec[0].bv_page = bh->b_page;
2979 bio->bi_io_vec[0].bv_len = bh->b_size;
2980 bio->bi_io_vec[0].bv_offset = bh_offset(bh);
2981
2982 bio->bi_vcnt = 1;
2983 bio->bi_idx = 0;
2984 bio->bi_size = bh->b_size;
2985
2986 bio->bi_end_io = end_bio_bh_io_sync;
2987 bio->bi_private = bh;
2988
2989 bio_get(bio);
2990 submit_bio(rw, bio);
2991
2992 if (bio_flagged(bio, BIO_EOPNOTSUPP))
2993 ret = -EOPNOTSUPP;
2994
2995 bio_put(bio);
2996 return ret;
2997}
2998EXPORT_SYMBOL(submit_bh);
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026void ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
3027{
3028 int i;
3029
3030 for (i = 0; i < nr; i++) {
3031 struct buffer_head *bh = bhs[i];
3032
3033 if (rw == SWRITE || rw == SWRITE_SYNC || rw == SWRITE_SYNC_PLUG)
3034 lock_buffer(bh);
3035 else if (!trylock_buffer(bh))
3036 continue;
3037
3038 if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC ||
3039 rw == SWRITE_SYNC_PLUG) {
3040 if (test_clear_buffer_dirty(bh)) {
3041 bh->b_end_io = end_buffer_write_sync;
3042 get_bh(bh);
3043 if (rw == SWRITE_SYNC)
3044 submit_bh(WRITE_SYNC, bh);
3045 else
3046 submit_bh(WRITE, bh);
3047 continue;
3048 }
3049 } else {
3050 if (!buffer_uptodate(bh)) {
3051 bh->b_end_io = end_buffer_read_sync;
3052 get_bh(bh);
3053 submit_bh(rw, bh);
3054 continue;
3055 }
3056 }
3057 unlock_buffer(bh);
3058 }
3059}
3060EXPORT_SYMBOL(ll_rw_block);
3061
3062
3063
3064
3065
3066
3067int sync_dirty_buffer(struct buffer_head *bh)
3068{
3069 int ret = 0;
3070
3071 WARN_ON(atomic_read(&bh->b_count) < 1);
3072 lock_buffer(bh);
3073 if (test_clear_buffer_dirty(bh)) {
3074 get_bh(bh);
3075 bh->b_end_io = end_buffer_write_sync;
3076 ret = submit_bh(WRITE_SYNC, bh);
3077 wait_on_buffer(bh);
3078 if (buffer_eopnotsupp(bh)) {
3079 clear_buffer_eopnotsupp(bh);
3080 ret = -EOPNOTSUPP;
3081 }
3082 if (!ret && !buffer_uptodate(bh))
3083 ret = -EIO;
3084 } else {
3085 unlock_buffer(bh);
3086 }
3087 return ret;
3088}
3089EXPORT_SYMBOL(sync_dirty_buffer);
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111static inline int buffer_busy(struct buffer_head *bh)
3112{
3113 return atomic_read(&bh->b_count) |
3114 (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock)));
3115}
3116
3117static int
3118drop_buffers(struct page *page, struct buffer_head **buffers_to_free)
3119{
3120 struct buffer_head *head = page_buffers(page);
3121 struct buffer_head *bh;
3122
3123 bh = head;
3124 do {
3125 if (buffer_write_io_error(bh) && page->mapping)
3126 set_bit(AS_EIO, &page->mapping->flags);
3127 if (buffer_busy(bh))
3128 goto failed;
3129 bh = bh->b_this_page;
3130 } while (bh != head);
3131
3132 do {
3133 struct buffer_head *next = bh->b_this_page;
3134
3135 if (bh->b_assoc_map)
3136 __remove_assoc_queue(bh);
3137 bh = next;
3138 } while (bh != head);
3139 *buffers_to_free = head;
3140 __clear_page_buffers(page);
3141 return 1;
3142failed:
3143 return 0;
3144}
3145
3146int try_to_free_buffers(struct page *page)
3147{
3148 struct address_space * const mapping = page->mapping;
3149 struct buffer_head *buffers_to_free = NULL;
3150 int ret = 0;
3151
3152 BUG_ON(!PageLocked(page));
3153 if (PageWriteback(page))
3154 return 0;
3155
3156 if (mapping == NULL) {
3157 ret = drop_buffers(page, &buffers_to_free);
3158 goto out;
3159 }
3160
3161 spin_lock(&mapping->private_lock);
3162 ret = drop_buffers(page, &buffers_to_free);
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178 if (ret)
3179 cancel_dirty_page(page, PAGE_CACHE_SIZE);
3180 spin_unlock(&mapping->private_lock);
3181out:
3182 if (buffers_to_free) {
3183 struct buffer_head *bh = buffers_to_free;
3184
3185 do {
3186 struct buffer_head *next = bh->b_this_page;
3187 free_buffer_head(bh);
3188 bh = next;
3189 } while (bh != buffers_to_free);
3190 }
3191 return ret;
3192}
3193EXPORT_SYMBOL(try_to_free_buffers);
3194
3195void block_sync_page(struct page *page)
3196{
3197 struct address_space *mapping;
3198
3199 smp_mb();
3200 mapping = page_mapping(page);
3201 if (mapping)
3202 blk_run_backing_dev(mapping->backing_dev_info, page);
3203}
3204EXPORT_SYMBOL(block_sync_page);
3205
3206
3207
3208
3209
3210
3211
3212
3213SYSCALL_DEFINE2(bdflush, int, func, long, data)
3214{
3215 static int msg_count;
3216
3217 if (!capable(CAP_SYS_ADMIN))
3218 return -EPERM;
3219
3220 if (msg_count < 5) {
3221 msg_count++;
3222 printk(KERN_INFO
3223 "warning: process `%s' used the obsolete bdflush"
3224 " system call\n", current->comm);
3225 printk(KERN_INFO "Fix your initscripts?\n");
3226 }
3227
3228 if (func == 1)
3229 do_exit(0);
3230 return 0;
3231}
3232
3233
3234
3235
3236static struct kmem_cache *bh_cachep;
3237
3238
3239
3240
3241
3242static int max_buffer_heads;
3243
3244int buffer_heads_over_limit;
3245
3246struct bh_accounting {
3247 int nr;
3248 int ratelimit;
3249};
3250
3251static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0};
3252
3253static void recalc_bh_state(void)
3254{
3255 int i;
3256 int tot = 0;
3257
3258 if (__get_cpu_var(bh_accounting).ratelimit++ < 4096)
3259 return;
3260 __get_cpu_var(bh_accounting).ratelimit = 0;
3261 for_each_online_cpu(i)
3262 tot += per_cpu(bh_accounting, i).nr;
3263 buffer_heads_over_limit = (tot > max_buffer_heads);
3264}
3265
3266struct buffer_head *alloc_buffer_head(gfp_t gfp_flags)
3267{
3268 struct buffer_head *ret = kmem_cache_alloc(bh_cachep, gfp_flags);
3269 if (ret) {
3270 INIT_LIST_HEAD(&ret->b_assoc_buffers);
3271 get_cpu_var(bh_accounting).nr++;
3272 recalc_bh_state();
3273 put_cpu_var(bh_accounting);
3274 }
3275 return ret;
3276}
3277EXPORT_SYMBOL(alloc_buffer_head);
3278
3279void free_buffer_head(struct buffer_head *bh)
3280{
3281 BUG_ON(!list_empty(&bh->b_assoc_buffers));
3282 kmem_cache_free(bh_cachep, bh);
3283 get_cpu_var(bh_accounting).nr--;
3284 recalc_bh_state();
3285 put_cpu_var(bh_accounting);
3286}
3287EXPORT_SYMBOL(free_buffer_head);
3288
3289static void buffer_exit_cpu(int cpu)
3290{
3291 int i;
3292 struct bh_lru *b = &per_cpu(bh_lrus, cpu);
3293
3294 for (i = 0; i < BH_LRU_SIZE; i++) {
3295 brelse(b->bhs[i]);
3296 b->bhs[i] = NULL;
3297 }
3298 get_cpu_var(bh_accounting).nr += per_cpu(bh_accounting, cpu).nr;
3299 per_cpu(bh_accounting, cpu).nr = 0;
3300 put_cpu_var(bh_accounting);
3301}
3302
3303static int buffer_cpu_notify(struct notifier_block *self,
3304 unsigned long action, void *hcpu)
3305{
3306 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
3307 buffer_exit_cpu((unsigned long)hcpu);
3308 return NOTIFY_OK;
3309}
3310
3311
3312
3313
3314
3315
3316
3317
3318int bh_uptodate_or_lock(struct buffer_head *bh)
3319{
3320 if (!buffer_uptodate(bh)) {
3321 lock_buffer(bh);
3322 if (!buffer_uptodate(bh))
3323 return 0;
3324 unlock_buffer(bh);
3325 }
3326 return 1;
3327}
3328EXPORT_SYMBOL(bh_uptodate_or_lock);
3329
3330
3331
3332
3333
3334
3335
3336int bh_submit_read(struct buffer_head *bh)
3337{
3338 BUG_ON(!buffer_locked(bh));
3339
3340 if (buffer_uptodate(bh)) {
3341 unlock_buffer(bh);
3342 return 0;
3343 }
3344
3345 get_bh(bh);
3346 bh->b_end_io = end_buffer_read_sync;
3347 submit_bh(READ, bh);
3348 wait_on_buffer(bh);
3349 if (buffer_uptodate(bh))
3350 return 0;
3351 return -EIO;
3352}
3353EXPORT_SYMBOL(bh_submit_read);
3354
3355static void
3356init_buffer_head(void *data)
3357{
3358 struct buffer_head *bh = data;
3359
3360 memset(bh, 0, sizeof(*bh));
3361 INIT_LIST_HEAD(&bh->b_assoc_buffers);
3362}
3363
3364void __init buffer_init(void)
3365{
3366 int nrpages;
3367
3368 bh_cachep = kmem_cache_create("buffer_head",
3369 sizeof(struct buffer_head), 0,
3370 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
3371 SLAB_MEM_SPREAD),
3372 init_buffer_head);
3373
3374
3375
3376
3377 nrpages = (nr_free_buffer_pages() * 10) / 100;
3378 max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head));
3379 hotcpu_notifier(buffer_cpu_notify, 0);
3380}
3381