2 * linux/fs/ext4/page-io.c
4 * This contains the new page_io functions for ext4
6 * Written by Theodore Ts'o, 2010.
9 #include <linux/module.h>
11 #include <linux/time.h>
12 #include <linux/jbd2.h>
13 #include <linux/highuid.h>
14 #include <linux/pagemap.h>
15 #include <linux/quotaops.h>
16 #include <linux/string.h>
17 #include <linux/buffer_head.h>
18 #include <linux/writeback.h>
19 #include <linux/pagevec.h>
20 #include <linux/mpage.h>
21 #include <linux/namei.h>
22 #include <linux/uio.h>
23 #include <linux/bio.h>
24 #include <linux/workqueue.h>
25 #include <linux/kernel.h>
26 #include <linux/slab.h>
28 #include "ext4_jbd2.h"
31 #include "ext4_extents.h"
33 static struct kmem_cache
*io_page_cachep
, *io_end_cachep
;
35 int __init
ext4_init_pageio(void)
37 io_page_cachep
= KMEM_CACHE(ext4_io_page
, SLAB_RECLAIM_ACCOUNT
);
38 if (io_page_cachep
== NULL
)
40 io_end_cachep
= KMEM_CACHE(ext4_io_end
, SLAB_RECLAIM_ACCOUNT
);
41 if (io_end_cachep
== NULL
) {
42 kmem_cache_destroy(io_page_cachep
);
48 void ext4_exit_pageio(void)
50 kmem_cache_destroy(io_end_cachep
);
51 kmem_cache_destroy(io_page_cachep
);
54 void ext4_ioend_wait(struct inode
*inode
)
56 wait_queue_head_t
*wq
= ext4_ioend_wq(inode
);
58 wait_event(*wq
, (atomic_read(&EXT4_I(inode
)->i_ioend_count
) == 0));
61 static void put_io_page(struct ext4_io_page
*io_page
)
63 if (atomic_dec_and_test(&io_page
->p_count
)) {
64 end_page_writeback(io_page
->p_page
);
65 put_page(io_page
->p_page
);
66 kmem_cache_free(io_page_cachep
, io_page
);
70 void ext4_free_io_end(ext4_io_end_t
*io
)
73 wait_queue_head_t
*wq
;
78 for (i
= 0; i
< io
->num_io_pages
; i
++)
79 put_io_page(io
->pages
[i
]);
81 wq
= ext4_ioend_wq(io
->inode
);
82 if (atomic_dec_and_test(&EXT4_I(io
->inode
)->i_ioend_count
) &&
85 kmem_cache_free(io_end_cachep
, io
);
89 * check a range of space and convert unwritten extents to written.
91 int ext4_end_io_nolock(ext4_io_end_t
*io
)
93 struct inode
*inode
= io
->inode
;
94 loff_t offset
= io
->offset
;
95 ssize_t size
= io
->size
;
96 wait_queue_head_t
*wq
;
99 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
101 io
, inode
->i_ino
, io
->list
.next
, io
->list
.prev
);
103 if (list_empty(&io
->list
))
106 if (!(io
->flag
& EXT4_IO_END_UNWRITTEN
))
109 ret
= ext4_convert_unwritten_extents(inode
, offset
, size
);
111 printk(KERN_EMERG
"%s: failed to convert unwritten "
112 "extents to written extents, error is %d "
113 "io is still on inode %lu aio dio list\n",
114 __func__
, ret
, inode
->i_ino
);
119 aio_complete(io
->iocb
, io
->result
, 0);
120 /* clear the DIO AIO unwritten flag */
121 if (io
->flag
& EXT4_IO_END_UNWRITTEN
) {
122 io
->flag
&= ~EXT4_IO_END_UNWRITTEN
;
123 /* Wake up anyone waiting on unwritten extent conversion */
124 wq
= ext4_ioend_wq(io
->inode
);
125 if (atomic_dec_and_test(&EXT4_I(inode
)->i_aiodio_unwritten
) &&
126 waitqueue_active(wq
)) {
135 * work on completed aio dio IO, to convert unwritten extents to extents
137 static void ext4_end_io_work(struct work_struct
*work
)
139 ext4_io_end_t
*io
= container_of(work
, ext4_io_end_t
, work
);
140 struct inode
*inode
= io
->inode
;
141 struct ext4_inode_info
*ei
= EXT4_I(inode
);
145 mutex_lock(&inode
->i_mutex
);
146 ret
= ext4_end_io_nolock(io
);
148 mutex_unlock(&inode
->i_mutex
);
152 spin_lock_irqsave(&ei
->i_completed_io_lock
, flags
);
153 if (!list_empty(&io
->list
))
154 list_del_init(&io
->list
);
155 spin_unlock_irqrestore(&ei
->i_completed_io_lock
, flags
);
156 mutex_unlock(&inode
->i_mutex
);
157 ext4_free_io_end(io
);
160 ext4_io_end_t
*ext4_init_io_end(struct inode
*inode
, gfp_t flags
)
162 ext4_io_end_t
*io
= kmem_cache_zalloc(io_end_cachep
, flags
);
164 atomic_inc(&EXT4_I(inode
)->i_ioend_count
);
166 INIT_WORK(&io
->work
, ext4_end_io_work
);
167 INIT_LIST_HEAD(&io
->list
);
173 * Print an buffer I/O error compatible with the fs/buffer.c. This
174 * provides compatibility with dmesg scrapers that look for a specific
175 * buffer I/O error message. We really need a unified error reporting
176 * structure to userspace ala Digital Unix's uerf system, but it's
177 * probably not going to happen in my lifetime, due to LKML politics...
179 static void buffer_io_error(struct buffer_head
*bh
)
181 char b
[BDEVNAME_SIZE
];
182 printk(KERN_ERR
"Buffer I/O error on device %s, logical block %llu\n",
183 bdevname(bh
->b_bdev
, b
),
184 (unsigned long long)bh
->b_blocknr
);
187 static void ext4_end_bio(struct bio
*bio
, int error
)
189 ext4_io_end_t
*io_end
= bio
->bi_private
;
190 struct workqueue_struct
*wq
;
194 sector_t bi_sector
= bio
->bi_sector
;
197 bio
->bi_private
= NULL
;
198 bio
->bi_end_io
= NULL
;
199 if (test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
203 for (i
= 0; i
< io_end
->num_io_pages
; i
++) {
204 struct page
*page
= io_end
->pages
[i
]->p_page
;
205 struct buffer_head
*bh
, *head
;
207 loff_t io_end_offset
;
211 set_bit(AS_EIO
, &page
->mapping
->flags
);
212 head
= page_buffers(page
);
215 io_end_offset
= io_end
->offset
+ io_end
->size
;
217 offset
= (sector_t
) page
->index
<< PAGE_CACHE_SHIFT
;
220 if ((offset
>= io_end
->offset
) &&
221 (offset
+bh
->b_size
<= io_end_offset
))
224 offset
+= bh
->b_size
;
225 bh
= bh
->b_this_page
;
226 } while (bh
!= head
);
229 put_io_page(io_end
->pages
[i
]);
231 io_end
->num_io_pages
= 0;
232 inode
= io_end
->inode
;
235 io_end
->flag
|= EXT4_IO_END_ERROR
;
236 ext4_warning(inode
->i_sb
, "I/O error writing to inode %lu "
237 "(offset %llu size %ld starting block %llu)",
239 (unsigned long long) io_end
->offset
,
242 bi_sector
>> (inode
->i_blkbits
- 9));
245 if (!(io_end
->flag
& EXT4_IO_END_UNWRITTEN
)) {
246 ext4_free_io_end(io_end
);
250 /* Add the io_end to per-inode completed io list*/
251 spin_lock_irqsave(&EXT4_I(inode
)->i_completed_io_lock
, flags
);
252 list_add_tail(&io_end
->list
, &EXT4_I(inode
)->i_completed_io_list
);
253 spin_unlock_irqrestore(&EXT4_I(inode
)->i_completed_io_lock
, flags
);
255 wq
= EXT4_SB(inode
->i_sb
)->dio_unwritten_wq
;
256 /* queue the work to convert unwritten extents to written */
257 queue_work(wq
, &io_end
->work
);
260 void ext4_io_submit(struct ext4_io_submit
*io
)
262 struct bio
*bio
= io
->io_bio
;
266 submit_bio(io
->io_op
, io
->io_bio
);
267 BUG_ON(bio_flagged(io
->io_bio
, BIO_EOPNOTSUPP
));
275 static int io_submit_init(struct ext4_io_submit
*io
,
277 struct writeback_control
*wbc
,
278 struct buffer_head
*bh
)
280 ext4_io_end_t
*io_end
;
281 struct page
*page
= bh
->b_page
;
282 int nvecs
= bio_get_nr_vecs(bh
->b_bdev
);
285 io_end
= ext4_init_io_end(inode
, GFP_NOFS
);
289 bio
= bio_alloc(GFP_NOIO
, nvecs
);
291 } while (bio
== NULL
);
293 bio
->bi_sector
= bh
->b_blocknr
* (bh
->b_size
>> 9);
294 bio
->bi_bdev
= bh
->b_bdev
;
295 bio
->bi_private
= io
->io_end
= io_end
;
296 bio
->bi_end_io
= ext4_end_bio
;
298 io_end
->offset
= (page
->index
<< PAGE_CACHE_SHIFT
) + bh_offset(bh
);
301 io
->io_op
= (wbc
->sync_mode
== WB_SYNC_ALL
? WRITE_SYNC
: WRITE
);
302 io
->io_next_block
= bh
->b_blocknr
;
306 static int io_submit_add_bh(struct ext4_io_submit
*io
,
307 struct ext4_io_page
*io_page
,
309 struct writeback_control
*wbc
,
310 struct buffer_head
*bh
)
312 ext4_io_end_t
*io_end
;
315 if (buffer_new(bh
)) {
316 clear_buffer_new(bh
);
317 unmap_underlying_metadata(bh
->b_bdev
, bh
->b_blocknr
);
320 if (!buffer_mapped(bh
) || buffer_delay(bh
)) {
321 if (!buffer_mapped(bh
))
322 clear_buffer_dirty(bh
);
328 if (io
->io_bio
&& bh
->b_blocknr
!= io
->io_next_block
) {
332 if (io
->io_bio
== NULL
) {
333 ret
= io_submit_init(io
, inode
, wbc
, bh
);
338 if ((io_end
->num_io_pages
>= MAX_IO_PAGES
) &&
339 (io_end
->pages
[io_end
->num_io_pages
-1] != io_page
))
340 goto submit_and_retry
;
341 if (buffer_uninit(bh
))
342 io
->io_end
->flag
|= EXT4_IO_END_UNWRITTEN
;
343 io
->io_end
->size
+= bh
->b_size
;
345 ret
= bio_add_page(io
->io_bio
, bh
->b_page
, bh
->b_size
, bh_offset(bh
));
346 if (ret
!= bh
->b_size
)
347 goto submit_and_retry
;
348 if ((io_end
->num_io_pages
== 0) ||
349 (io_end
->pages
[io_end
->num_io_pages
-1] != io_page
)) {
350 io_end
->pages
[io_end
->num_io_pages
++] = io_page
;
351 atomic_inc(&io_page
->p_count
);
356 int ext4_bio_write_page(struct ext4_io_submit
*io
,
359 struct writeback_control
*wbc
)
361 struct inode
*inode
= page
->mapping
->host
;
362 unsigned block_start
, block_end
, blocksize
;
363 struct ext4_io_page
*io_page
;
364 struct buffer_head
*bh
, *head
;
367 blocksize
= 1 << inode
->i_blkbits
;
369 BUG_ON(!PageLocked(page
));
370 BUG_ON(PageWriteback(page
));
372 io_page
= kmem_cache_alloc(io_page_cachep
, GFP_NOFS
);
374 set_page_dirty(page
);
378 io_page
->p_page
= page
;
379 atomic_set(&io_page
->p_count
, 1);
381 set_page_writeback(page
);
382 ClearPageError(page
);
384 for (bh
= head
= page_buffers(page
), block_start
= 0;
385 bh
!= head
|| !block_start
;
386 block_start
= block_end
, bh
= bh
->b_this_page
) {
388 block_end
= block_start
+ blocksize
;
389 if (block_start
>= len
) {
390 clear_buffer_dirty(bh
);
391 set_buffer_uptodate(bh
);
394 clear_buffer_dirty(bh
);
395 ret
= io_submit_add_bh(io
, io_page
, inode
, wbc
, bh
);
398 * We only get here on ENOMEM. Not much else
399 * we can do but mark the page as dirty, and
400 * better luck next time.
402 set_page_dirty(page
);
408 * If the page was truncated before we could do the writeback,
409 * or we had a memory allocation error while trying to write
410 * the first buffer head, we won't have submitted any pages for
411 * I/O. In that case we need to make sure we've cleared the
412 * PageWriteback bit from the page to prevent the system from
415 put_io_page(io_page
);