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Joern Engel5db53f32009-11-20 20:13:39 +01001/*
2 * fs/logfs/dev_bdev.c - Device access methods for block devices
3 *
4 * As should be obvious for Linux kernel code, license is GPLv2
5 *
6 * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
7 */
8#include "logfs.h"
9#include <linux/bio.h>
10#include <linux/blkdev.h>
11#include <linux/buffer_head.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090012#include <linux/gfp.h>
Linus Torvalds268bb0c2011-05-20 12:50:29 -070013#include <linux/prefetch.h>
Joern Engel5db53f32009-11-20 20:13:39 +010014
15#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1))
16
Joern Engel5db53f32009-11-20 20:13:39 +010017static int sync_request(struct page *page, struct block_device *bdev, int rw)
18{
19 struct bio bio;
20 struct bio_vec bio_vec;
Joern Engel5db53f32009-11-20 20:13:39 +010021
22 bio_init(&bio);
Prasad Joshicd8bfa92012-04-02 09:23:04 +053023 bio.bi_max_vecs = 1;
Joern Engel5db53f32009-11-20 20:13:39 +010024 bio.bi_io_vec = &bio_vec;
25 bio_vec.bv_page = page;
26 bio_vec.bv_len = PAGE_SIZE;
27 bio_vec.bv_offset = 0;
28 bio.bi_vcnt = 1;
Joern Engel5db53f32009-11-20 20:13:39 +010029 bio.bi_bdev = bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -070030 bio.bi_iter.bi_sector = page->index * (PAGE_SIZE >> 9);
31 bio.bi_iter.bi_size = PAGE_SIZE;
Joern Engel5db53f32009-11-20 20:13:39 +010032
Kent Overstreet33879d42013-11-23 22:33:32 -080033 return submit_bio_wait(rw, &bio);
Joern Engel5db53f32009-11-20 20:13:39 +010034}
35
36static int bdev_readpage(void *_sb, struct page *page)
37{
38 struct super_block *sb = _sb;
39 struct block_device *bdev = logfs_super(sb)->s_bdev;
40 int err;
41
42 err = sync_request(page, bdev, READ);
43 if (err) {
44 ClearPageUptodate(page);
45 SetPageError(page);
46 } else {
47 SetPageUptodate(page);
48 ClearPageError(page);
49 }
50 unlock_page(page);
51 return err;
52}
53
54static DECLARE_WAIT_QUEUE_HEAD(wq);
55
Christoph Hellwig4246a0b2015-07-20 15:29:37 +020056static void writeseg_end_io(struct bio *bio)
Joern Engel5db53f32009-11-20 20:13:39 +010057{
Kent Overstreet2c30c712013-11-07 12:20:26 -080058 struct bio_vec *bvec;
59 int i;
Joern Engel5db53f32009-11-20 20:13:39 +010060 struct super_block *sb = bio->bi_private;
61 struct logfs_super *super = logfs_super(sb);
Joern Engel5db53f32009-11-20 20:13:39 +010062
Christoph Hellwig4246a0b2015-07-20 15:29:37 +020063 BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */
Joern Engel5db53f32009-11-20 20:13:39 +010064
Kent Overstreet2c30c712013-11-07 12:20:26 -080065 bio_for_each_segment_all(bvec, bio, i) {
66 end_page_writeback(bvec->bv_page);
67 page_cache_release(bvec->bv_page);
68 }
Joern Engel5db53f32009-11-20 20:13:39 +010069 bio_put(bio);
70 if (atomic_dec_and_test(&super->s_pending_writes))
71 wake_up(&wq);
72}
73
74static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
75 size_t nr_pages)
76{
77 struct logfs_super *super = logfs_super(sb);
78 struct address_space *mapping = super->s_mapping_inode->i_mapping;
79 struct bio *bio;
80 struct page *page;
Prasad Joshi9f0bbd82012-07-23 10:32:11 +053081 unsigned int max_pages;
Joern Engel5db53f32009-11-20 20:13:39 +010082 int i;
83
Sudip Mukherjeece4f2fd2015-11-05 18:43:49 -080084 max_pages = min_t(size_t, nr_pages, BIO_MAX_PAGES);
Prasad Joshi9f0bbd82012-07-23 10:32:11 +053085
Joern Engel5db53f32009-11-20 20:13:39 +010086 bio = bio_alloc(GFP_NOFS, max_pages);
Joern Engel59fe27c2010-03-17 13:47:45 +010087 BUG_ON(!bio);
Joern Engel5db53f32009-11-20 20:13:39 +010088
89 for (i = 0; i < nr_pages; i++) {
90 if (i >= max_pages) {
91 /* Block layer cannot split bios :( */
92 bio->bi_vcnt = i;
Kent Overstreet4f024f32013-10-11 15:44:27 -070093 bio->bi_iter.bi_size = i * PAGE_SIZE;
Joern Engel5db53f32009-11-20 20:13:39 +010094 bio->bi_bdev = super->s_bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -070095 bio->bi_iter.bi_sector = ofs >> 9;
Joern Engel5db53f32009-11-20 20:13:39 +010096 bio->bi_private = sb;
97 bio->bi_end_io = writeseg_end_io;
98 atomic_inc(&super->s_pending_writes);
99 submit_bio(WRITE, bio);
100
101 ofs += i * PAGE_SIZE;
102 index += i;
103 nr_pages -= i;
104 i = 0;
105
106 bio = bio_alloc(GFP_NOFS, max_pages);
107 BUG_ON(!bio);
108 }
109 page = find_lock_page(mapping, index + i);
110 BUG_ON(!page);
111 bio->bi_io_vec[i].bv_page = page;
112 bio->bi_io_vec[i].bv_len = PAGE_SIZE;
113 bio->bi_io_vec[i].bv_offset = 0;
114
115 BUG_ON(PageWriteback(page));
116 set_page_writeback(page);
117 unlock_page(page);
118 }
119 bio->bi_vcnt = nr_pages;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700120 bio->bi_iter.bi_size = nr_pages * PAGE_SIZE;
Joern Engel5db53f32009-11-20 20:13:39 +0100121 bio->bi_bdev = super->s_bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700122 bio->bi_iter.bi_sector = ofs >> 9;
Joern Engel5db53f32009-11-20 20:13:39 +0100123 bio->bi_private = sb;
124 bio->bi_end_io = writeseg_end_io;
125 atomic_inc(&super->s_pending_writes);
126 submit_bio(WRITE, bio);
127 return 0;
128}
129
130static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len)
131{
132 struct logfs_super *super = logfs_super(sb);
133 int head;
134
135 BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO);
136
137 if (len == 0) {
138 /* This can happen when the object fit perfectly into a
139 * segment, the segment gets written per sync and subsequently
140 * closed.
141 */
142 return;
143 }
144 head = ofs & (PAGE_SIZE - 1);
145 if (head) {
146 ofs -= head;
147 len += head;
148 }
149 len = PAGE_ALIGN(len);
150 __bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT);
Joern Engel5db53f32009-11-20 20:13:39 +0100151}
152
Joern Engel94215022010-03-04 21:30:58 +0100153
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200154static void erase_end_io(struct bio *bio)
Joern Engel94215022010-03-04 21:30:58 +0100155{
Joern Engel94215022010-03-04 21:30:58 +0100156 struct super_block *sb = bio->bi_private;
157 struct logfs_super *super = logfs_super(sb);
158
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200159 BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */
Joern Engel94215022010-03-04 21:30:58 +0100160 BUG_ON(bio->bi_vcnt == 0);
161 bio_put(bio);
162 if (atomic_dec_and_test(&super->s_pending_writes))
163 wake_up(&wq);
164}
165
166static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
167 size_t nr_pages)
Joern Engel5db53f32009-11-20 20:13:39 +0100168{
169 struct logfs_super *super = logfs_super(sb);
Joern Engel94215022010-03-04 21:30:58 +0100170 struct bio *bio;
Prasad Joshi9f0bbd82012-07-23 10:32:11 +0530171 unsigned int max_pages;
Joern Engel94215022010-03-04 21:30:58 +0100172 int i;
173
Sudip Mukherjeece4f2fd2015-11-05 18:43:49 -0800174 max_pages = min_t(size_t, nr_pages, BIO_MAX_PAGES);
Prasad Joshi9f0bbd82012-07-23 10:32:11 +0530175
Joern Engel94215022010-03-04 21:30:58 +0100176 bio = bio_alloc(GFP_NOFS, max_pages);
Joern Engel59fe27c2010-03-17 13:47:45 +0100177 BUG_ON(!bio);
Joern Engel94215022010-03-04 21:30:58 +0100178
179 for (i = 0; i < nr_pages; i++) {
180 if (i >= max_pages) {
181 /* Block layer cannot split bios :( */
182 bio->bi_vcnt = i;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700183 bio->bi_iter.bi_size = i * PAGE_SIZE;
Joern Engel94215022010-03-04 21:30:58 +0100184 bio->bi_bdev = super->s_bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700185 bio->bi_iter.bi_sector = ofs >> 9;
Joern Engel94215022010-03-04 21:30:58 +0100186 bio->bi_private = sb;
187 bio->bi_end_io = erase_end_io;
188 atomic_inc(&super->s_pending_writes);
189 submit_bio(WRITE, bio);
190
191 ofs += i * PAGE_SIZE;
192 index += i;
193 nr_pages -= i;
194 i = 0;
195
196 bio = bio_alloc(GFP_NOFS, max_pages);
197 BUG_ON(!bio);
198 }
199 bio->bi_io_vec[i].bv_page = super->s_erase_page;
200 bio->bi_io_vec[i].bv_len = PAGE_SIZE;
201 bio->bi_io_vec[i].bv_offset = 0;
202 }
203 bio->bi_vcnt = nr_pages;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700204 bio->bi_iter.bi_size = nr_pages * PAGE_SIZE;
Joern Engel94215022010-03-04 21:30:58 +0100205 bio->bi_bdev = super->s_bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700206 bio->bi_iter.bi_sector = ofs >> 9;
Joern Engel94215022010-03-04 21:30:58 +0100207 bio->bi_private = sb;
208 bio->bi_end_io = erase_end_io;
209 atomic_inc(&super->s_pending_writes);
210 submit_bio(WRITE, bio);
211 return 0;
212}
213
214static int bdev_erase(struct super_block *sb, loff_t to, size_t len,
215 int ensure_write)
216{
217 struct logfs_super *super = logfs_super(sb);
Joern Engel5db53f32009-11-20 20:13:39 +0100218
219 BUG_ON(to & (PAGE_SIZE - 1));
220 BUG_ON(len & (PAGE_SIZE - 1));
221
Joern Engel94215022010-03-04 21:30:58 +0100222 if (super->s_flags & LOGFS_SB_FLAG_RO)
Joern Engel5db53f32009-11-20 20:13:39 +0100223 return -EROFS;
224
Joern Engel94215022010-03-04 21:30:58 +0100225 if (ensure_write) {
226 /*
227 * Object store doesn't care whether erases happen or not.
228 * But for the journal they are required. Otherwise a scan
229 * can find an old commit entry and assume it is the current
230 * one, travelling back in time.
231 */
232 do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT);
Joern Engel5db53f32009-11-20 20:13:39 +0100233 }
Joern Engel94215022010-03-04 21:30:58 +0100234
Joern Engel5db53f32009-11-20 20:13:39 +0100235 return 0;
236}
237
238static void bdev_sync(struct super_block *sb)
239{
240 struct logfs_super *super = logfs_super(sb);
241
242 wait_event(wq, atomic_read(&super->s_pending_writes) == 0);
243}
244
245static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs)
246{
247 struct logfs_super *super = logfs_super(sb);
248 struct address_space *mapping = super->s_mapping_inode->i_mapping;
249 filler_t *filler = bdev_readpage;
250
251 *ofs = 0;
252 return read_cache_page(mapping, 0, filler, sb);
253}
254
255static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs)
256{
257 struct logfs_super *super = logfs_super(sb);
258 struct address_space *mapping = super->s_mapping_inode->i_mapping;
259 filler_t *filler = bdev_readpage;
260 u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000;
261 pgoff_t index = pos >> PAGE_SHIFT;
262
263 *ofs = pos;
264 return read_cache_page(mapping, index, filler, sb);
265}
266
267static int bdev_write_sb(struct super_block *sb, struct page *page)
268{
269 struct block_device *bdev = logfs_super(sb)->s_bdev;
270
271 /* Nothing special to do for block devices. */
272 return sync_request(page, bdev, WRITE);
273}
274
Al Viroe5a07262010-07-26 12:06:00 +0400275static void bdev_put_device(struct logfs_super *s)
Joern Engel5db53f32009-11-20 20:13:39 +0100276{
Tejun Heoe525fd82010-11-13 11:55:17 +0100277 blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
Joern Engel5db53f32009-11-20 20:13:39 +0100278}
279
Joern Engel6f485b412010-05-07 19:38:40 +0200280static int bdev_can_write_buf(struct super_block *sb, u64 ofs)
281{
282 return 0;
283}
284
Joern Engel5db53f32009-11-20 20:13:39 +0100285static const struct logfs_device_ops bd_devops = {
286 .find_first_sb = bdev_find_first_sb,
287 .find_last_sb = bdev_find_last_sb,
288 .write_sb = bdev_write_sb,
289 .readpage = bdev_readpage,
290 .writeseg = bdev_writeseg,
291 .erase = bdev_erase,
Joern Engel6f485b412010-05-07 19:38:40 +0200292 .can_write_buf = bdev_can_write_buf,
Joern Engel5db53f32009-11-20 20:13:39 +0100293 .sync = bdev_sync,
294 .put_device = bdev_put_device,
295};
296
Al Viro7d945a32010-07-26 11:53:30 +0400297int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type,
298 const char *devname)
Joern Engel5db53f32009-11-20 20:13:39 +0100299{
300 struct block_device *bdev;
301
Tejun Heod4d77622010-11-13 11:55:18 +0100302 bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
303 type);
Al Viro7d945a32010-07-26 11:53:30 +0400304 if (IS_ERR(bdev))
Joern Engel5db53f32009-11-20 20:13:39 +0100305 return PTR_ERR(bdev);
306
307 if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
308 int mtdnr = MINOR(bdev->bd_dev);
Tejun Heoe525fd82010-11-13 11:55:17 +0100309 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
Al Viro7d945a32010-07-26 11:53:30 +0400310 return logfs_get_sb_mtd(p, mtdnr);
Joern Engel5db53f32009-11-20 20:13:39 +0100311 }
312
Al Viro0d85c792010-07-26 11:33:39 +0400313 p->s_bdev = bdev;
314 p->s_mtd = NULL;
315 p->s_devops = &bd_devops;
Al Viro7d945a32010-07-26 11:53:30 +0400316 return 0;
Joern Engel5db53f32009-11-20 20:13:39 +0100317}