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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - mm/page_io.c
06a8842a6ec612dbda8071f94d15423326a375f4
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
6 * Swap reorganised 29.12.95,
7 * Asynchronous swapping added 30.12.95. Stephen Tweedie
8 * Removed race in async swapping. 14.4.1996. Bruno Haible
9 * Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
10 * Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
14 #include <linux/kernel_stat.h>
15 #include <linux/gfp.h>
16 #include <linux/pagemap.h>
17 #include <linux/swap.h>
18 #include <linux/bio.h>
19 #include <linux/swapops.h>
20 #include <linux/buffer_head.h>
21 #include <linux/writeback.h>
22 #include <linux/frontswap.h>
23 #include <linux/aio.h>
24 #include <asm/pgtable.h>
26 static struct bio
*get_swap_bio(gfp_t gfp_flags
,
27 struct page
*page
, bio_end_io_t end_io
)
31 bio
= bio_alloc(gfp_flags
, 1);
33 bio
->bi_sector
= map_swap_page(page
, &bio
->bi_bdev
);
34 bio
->bi_sector
<<= PAGE_SHIFT
- 9;
35 bio
->bi_io_vec
[0].bv_page
= page
;
36 bio
->bi_io_vec
[0].bv_len
= PAGE_SIZE
;
37 bio
->bi_io_vec
[0].bv_offset
= 0;
40 bio
->bi_size
= PAGE_SIZE
;
41 bio
->bi_end_io
= end_io
;
46 void end_swap_bio_write(struct bio
*bio
, int err
)
48 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
49 struct page
*page
= bio
->bi_io_vec
[0].bv_page
;
54 * We failed to write the page out to swap-space.
55 * Re-dirty the page in order to avoid it being reclaimed.
56 * Also print a dire warning that things will go BAD (tm)
59 * Also clear PG_reclaim to avoid rotate_reclaimable_page()
62 printk(KERN_ALERT
"Write-error on swap-device (%u:%u:%Lu)\n",
63 imajor(bio
->bi_bdev
->bd_inode
),
64 iminor(bio
->bi_bdev
->bd_inode
),
65 (unsigned long long)bio
->bi_sector
);
66 ClearPageReclaim(page
);
68 end_page_writeback(page
);
72 void end_swap_bio_read(struct bio
*bio
, int err
)
74 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
75 struct page
*page
= bio
->bi_io_vec
[0].bv_page
;
79 ClearPageUptodate(page
);
80 printk(KERN_ALERT
"Read-error on swap-device (%u:%u:%Lu)\n",
81 imajor(bio
->bi_bdev
->bd_inode
),
82 iminor(bio
->bi_bdev
->bd_inode
),
83 (unsigned long long)bio
->bi_sector
);
85 SetPageUptodate(page
);
91 int generic_swapfile_activate(struct swap_info_struct
*sis
,
92 struct file
*swap_file
,
95 struct address_space
*mapping
= swap_file
->f_mapping
;
96 struct inode
*inode
= mapping
->host
;
97 unsigned blocks_per_page
;
98 unsigned long page_no
;
100 sector_t probe_block
;
102 sector_t lowest_block
= -1;
103 sector_t highest_block
= 0;
107 blkbits
= inode
->i_blkbits
;
108 blocks_per_page
= PAGE_SIZE
>> blkbits
;
111 * Map all the blocks into the extent list. This code doesn't try
116 last_block
= i_size_read(inode
) >> blkbits
;
117 while ((probe_block
+ blocks_per_page
) <= last_block
&&
118 page_no
< sis
->max
) {
119 unsigned block_in_page
;
120 sector_t first_block
;
122 first_block
= bmap(inode
, probe_block
);
123 if (first_block
== 0)
127 * It must be PAGE_SIZE aligned on-disk
129 if (first_block
& (blocks_per_page
- 1)) {
134 for (block_in_page
= 1; block_in_page
< blocks_per_page
;
138 block
= bmap(inode
, probe_block
+ block_in_page
);
141 if (block
!= first_block
+ block_in_page
) {
148 first_block
>>= (PAGE_SHIFT
- blkbits
);
149 if (page_no
) { /* exclude the header page */
150 if (first_block
< lowest_block
)
151 lowest_block
= first_block
;
152 if (first_block
> highest_block
)
153 highest_block
= first_block
;
157 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
159 ret
= add_swap_extent(sis
, page_no
, 1, first_block
);
164 probe_block
+= blocks_per_page
;
169 *span
= 1 + highest_block
- lowest_block
;
171 page_no
= 1; /* force Empty message */
173 sis
->pages
= page_no
- 1;
174 sis
->highest_bit
= page_no
- 1;
178 printk(KERN_ERR
"swapon: swapfile has holes\n");
184 * We may have stale swap cache pages in memory: notice
185 * them here and get rid of the unnecessary final write.
187 int swap_writepage(struct page
*page
, struct writeback_control
*wbc
)
191 if (try_to_free_swap(page
)) {
195 if (frontswap_store(page
) == 0) {
196 set_page_writeback(page
);
198 end_page_writeback(page
);
201 ret
= __swap_writepage(page
, wbc
, end_swap_bio_write
);
206 int __swap_writepage(struct page
*page
, struct writeback_control
*wbc
,
207 void (*end_write_func
)(struct bio
*, int))
210 int ret
= 0, rw
= WRITE
;
211 struct swap_info_struct
*sis
= page_swap_info(page
);
213 if (sis
->flags
& SWP_FILE
) {
215 struct file
*swap_file
= sis
->swap_file
;
216 struct address_space
*mapping
= swap_file
->f_mapping
;
218 .iov_base
= kmap(page
),
219 .iov_len
= PAGE_SIZE
,
222 init_sync_kiocb(&kiocb
, swap_file
);
223 kiocb
.ki_pos
= page_file_offset(page
);
224 kiocb
.ki_left
= PAGE_SIZE
;
225 kiocb
.ki_nbytes
= PAGE_SIZE
;
227 set_page_writeback(page
);
229 ret
= mapping
->a_ops
->direct_IO(KERNEL_WRITE
,
233 if (ret
== PAGE_SIZE
) {
234 count_vm_event(PSWPOUT
);
238 * In the case of swap-over-nfs, this can be a
239 * temporary failure if the system has limited
240 * memory for allocating transmit buffers.
241 * Mark the page dirty and avoid
242 * rotate_reclaimable_page but rate-limit the
243 * messages but do not flag PageError like
244 * the normal direct-to-bio case as it could
247 set_page_dirty(page
);
248 ClearPageReclaim(page
);
249 pr_err_ratelimited("Write error on dio swapfile (%Lu)\n",
250 page_file_offset(page
));
252 end_page_writeback(page
);
256 bio
= get_swap_bio(GFP_NOIO
, page
, end_write_func
);
258 set_page_dirty(page
);
263 if (wbc
->sync_mode
== WB_SYNC_ALL
)
265 count_vm_event(PSWPOUT
);
266 set_page_writeback(page
);
273 int swap_readpage(struct page
*page
)
277 struct swap_info_struct
*sis
= page_swap_info(page
);
279 VM_BUG_ON(!PageLocked(page
));
280 VM_BUG_ON(PageUptodate(page
));
281 if (frontswap_load(page
) == 0) {
282 SetPageUptodate(page
);
287 if (sis
->flags
& SWP_FILE
) {
288 struct file
*swap_file
= sis
->swap_file
;
289 struct address_space
*mapping
= swap_file
->f_mapping
;
291 ret
= mapping
->a_ops
->readpage(swap_file
, page
);
293 count_vm_event(PSWPIN
);
297 bio
= get_swap_bio(GFP_KERNEL
, page
, end_swap_bio_read
);
303 count_vm_event(PSWPIN
);
304 submit_bio(READ
, bio
);
309 int swap_set_page_dirty(struct page
*page
)
311 struct swap_info_struct
*sis
= page_swap_info(page
);
313 if (sis
->flags
& SWP_FILE
) {
314 struct address_space
*mapping
= sis
->swap_file
->f_mapping
;
315 return mapping
->a_ops
->set_page_dirty(page
);
317 return __set_page_dirty_no_writeback(page
);