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-rw-r--r--fs/logfs/dev_bdev.c327
1 files changed, 327 insertions, 0 deletions
diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
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+++ b/fs/logfs/dev_bdev.c
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1/*
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>
12
13#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1))
14
15static void request_complete(struct bio *bio, int err)
16{
17 complete((struct completion *)bio->bi_private);
18}
19
20static int sync_request(struct page *page, struct block_device *bdev, int rw)
21{
22 struct bio bio;
23 struct bio_vec bio_vec;
24 struct completion complete;
25
26 bio_init(&bio);
27 bio.bi_io_vec = &bio_vec;
28 bio_vec.bv_page = page;
29 bio_vec.bv_len = PAGE_SIZE;
30 bio_vec.bv_offset = 0;
31 bio.bi_vcnt = 1;
32 bio.bi_idx = 0;
33 bio.bi_size = PAGE_SIZE;
34 bio.bi_bdev = bdev;
35 bio.bi_sector = page->index * (PAGE_SIZE >> 9);
36 init_completion(&complete);
37 bio.bi_private = &complete;
38 bio.bi_end_io = request_complete;
39
40 submit_bio(rw, &bio);
41 generic_unplug_device(bdev_get_queue(bdev));
42 wait_for_completion(&complete);
43 return test_bit(BIO_UPTODATE, &bio.bi_flags) ? 0 : -EIO;
44}
45
46static int bdev_readpage(void *_sb, struct page *page)
47{
48 struct super_block *sb = _sb;
49 struct block_device *bdev = logfs_super(sb)->s_bdev;
50 int err;
51
52 err = sync_request(page, bdev, READ);
53 if (err) {
54 ClearPageUptodate(page);
55 SetPageError(page);
56 } else {
57 SetPageUptodate(page);
58 ClearPageError(page);
59 }
60 unlock_page(page);
61 return err;
62}
63
64static DECLARE_WAIT_QUEUE_HEAD(wq);
65
66static void writeseg_end_io(struct bio *bio, int err)
67{
68 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
69 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
70 struct super_block *sb = bio->bi_private;
71 struct logfs_super *super = logfs_super(sb);
72 struct page *page;
73
74 BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */
75 BUG_ON(err);
76 BUG_ON(bio->bi_vcnt == 0);
77 do {
78 page = bvec->bv_page;
79 if (--bvec >= bio->bi_io_vec)
80 prefetchw(&bvec->bv_page->flags);
81
82 end_page_writeback(page);
83 } while (bvec >= bio->bi_io_vec);
84 bio_put(bio);
85 if (atomic_dec_and_test(&super->s_pending_writes))
86 wake_up(&wq);
87}
88
89static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
90 size_t nr_pages)
91{
92 struct logfs_super *super = logfs_super(sb);
93 struct address_space *mapping = super->s_mapping_inode->i_mapping;
94 struct bio *bio;
95 struct page *page;
96 struct request_queue *q = bdev_get_queue(sb->s_bdev);
97 unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
98 int i;
99
100 bio = bio_alloc(GFP_NOFS, max_pages);
101 BUG_ON(!bio); /* FIXME: handle this */
102
103 for (i = 0; i < nr_pages; i++) {
104 if (i >= max_pages) {
105 /* Block layer cannot split bios :( */
106 bio->bi_vcnt = i;
107 bio->bi_idx = 0;
108 bio->bi_size = i * PAGE_SIZE;
109 bio->bi_bdev = super->s_bdev;
110 bio->bi_sector = ofs >> 9;
111 bio->bi_private = sb;
112 bio->bi_end_io = writeseg_end_io;
113 atomic_inc(&super->s_pending_writes);
114 submit_bio(WRITE, bio);
115
116 ofs += i * PAGE_SIZE;
117 index += i;
118 nr_pages -= i;
119 i = 0;
120
121 bio = bio_alloc(GFP_NOFS, max_pages);
122 BUG_ON(!bio);
123 }
124 page = find_lock_page(mapping, index + i);
125 BUG_ON(!page);
126 bio->bi_io_vec[i].bv_page = page;
127 bio->bi_io_vec[i].bv_len = PAGE_SIZE;
128 bio->bi_io_vec[i].bv_offset = 0;
129
130 BUG_ON(PageWriteback(page));
131 set_page_writeback(page);
132 unlock_page(page);
133 }
134 bio->bi_vcnt = nr_pages;
135 bio->bi_idx = 0;
136 bio->bi_size = nr_pages * PAGE_SIZE;
137 bio->bi_bdev = super->s_bdev;
138 bio->bi_sector = ofs >> 9;
139 bio->bi_private = sb;
140 bio->bi_end_io = writeseg_end_io;
141 atomic_inc(&super->s_pending_writes);
142 submit_bio(WRITE, bio);
143 return 0;
144}
145
146static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len)
147{
148 struct logfs_super *super = logfs_super(sb);
149 int head;
150
151 BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO);
152
153 if (len == 0) {
154 /* This can happen when the object fit perfectly into a
155 * segment, the segment gets written per sync and subsequently
156 * closed.
157 */
158 return;
159 }
160 head = ofs & (PAGE_SIZE - 1);
161 if (head) {
162 ofs -= head;
163 len += head;
164 }
165 len = PAGE_ALIGN(len);
166 __bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT);
167 generic_unplug_device(bdev_get_queue(logfs_super(sb)->s_bdev));
168}
169
170
171static void erase_end_io(struct bio *bio, int err)
172{
173 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
174 struct super_block *sb = bio->bi_private;
175 struct logfs_super *super = logfs_super(sb);
176
177 BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */
178 BUG_ON(err);
179 BUG_ON(bio->bi_vcnt == 0);
180 bio_put(bio);
181 if (atomic_dec_and_test(&super->s_pending_writes))
182 wake_up(&wq);
183}
184
185static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
186 size_t nr_pages)
187{
188 struct logfs_super *super = logfs_super(sb);
189 struct bio *bio;
190 struct request_queue *q = bdev_get_queue(sb->s_bdev);
191 unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
192 int i;
193
194 bio = bio_alloc(GFP_NOFS, max_pages);
195 BUG_ON(!bio); /* FIXME: handle this */
196
197 for (i = 0; i < nr_pages; i++) {
198 if (i >= max_pages) {
199 /* Block layer cannot split bios :( */
200 bio->bi_vcnt = i;
201 bio->bi_idx = 0;
202 bio->bi_size = i * PAGE_SIZE;
203 bio->bi_bdev = super->s_bdev;
204 bio->bi_sector = ofs >> 9;
205 bio->bi_private = sb;
206 bio->bi_end_io = erase_end_io;
207 atomic_inc(&super->s_pending_writes);
208 submit_bio(WRITE, bio);
209
210 ofs += i * PAGE_SIZE;
211 index += i;
212 nr_pages -= i;
213 i = 0;
214
215 bio = bio_alloc(GFP_NOFS, max_pages);
216 BUG_ON(!bio);
217 }
218 bio->bi_io_vec[i].bv_page = super->s_erase_page;
219 bio->bi_io_vec[i].bv_len = PAGE_SIZE;
220 bio->bi_io_vec[i].bv_offset = 0;
221 }
222 bio->bi_vcnt = nr_pages;
223 bio->bi_idx = 0;
224 bio->bi_size = nr_pages * PAGE_SIZE;
225 bio->bi_bdev = super->s_bdev;
226 bio->bi_sector = ofs >> 9;
227 bio->bi_private = sb;
228 bio->bi_end_io = erase_end_io;
229 atomic_inc(&super->s_pending_writes);
230 submit_bio(WRITE, bio);
231 return 0;
232}
233
234static int bdev_erase(struct super_block *sb, loff_t to, size_t len,
235 int ensure_write)
236{
237 struct logfs_super *super = logfs_super(sb);
238
239 BUG_ON(to & (PAGE_SIZE - 1));
240 BUG_ON(len & (PAGE_SIZE - 1));
241
242 if (super->s_flags & LOGFS_SB_FLAG_RO)
243 return -EROFS;
244
245 if (ensure_write) {
246 /*
247 * Object store doesn't care whether erases happen or not.
248 * But for the journal they are required. Otherwise a scan
249 * can find an old commit entry and assume it is the current
250 * one, travelling back in time.
251 */
252 do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT);
253 }
254
255 return 0;
256}
257
258static void bdev_sync(struct super_block *sb)
259{
260 struct logfs_super *super = logfs_super(sb);
261
262 wait_event(wq, atomic_read(&super->s_pending_writes) == 0);
263}
264
265static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs)
266{
267 struct logfs_super *super = logfs_super(sb);
268 struct address_space *mapping = super->s_mapping_inode->i_mapping;
269 filler_t *filler = bdev_readpage;
270
271 *ofs = 0;
272 return read_cache_page(mapping, 0, filler, sb);
273}
274
275static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs)
276{
277 struct logfs_super *super = logfs_super(sb);
278 struct address_space *mapping = super->s_mapping_inode->i_mapping;
279 filler_t *filler = bdev_readpage;
280 u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000;
281 pgoff_t index = pos >> PAGE_SHIFT;
282
283 *ofs = pos;
284 return read_cache_page(mapping, index, filler, sb);
285}
286
287static int bdev_write_sb(struct super_block *sb, struct page *page)
288{
289 struct block_device *bdev = logfs_super(sb)->s_bdev;
290
291 /* Nothing special to do for block devices. */
292 return sync_request(page, bdev, WRITE);
293}
294
295static void bdev_put_device(struct super_block *sb)
296{
297 close_bdev_exclusive(logfs_super(sb)->s_bdev, FMODE_READ|FMODE_WRITE);
298}
299
300static const struct logfs_device_ops bd_devops = {
301 .find_first_sb = bdev_find_first_sb,
302 .find_last_sb = bdev_find_last_sb,
303 .write_sb = bdev_write_sb,
304 .readpage = bdev_readpage,
305 .writeseg = bdev_writeseg,
306 .erase = bdev_erase,
307 .sync = bdev_sync,
308 .put_device = bdev_put_device,
309};
310
311int logfs_get_sb_bdev(struct file_system_type *type, int flags,
312 const char *devname, struct vfsmount *mnt)
313{
314 struct block_device *bdev;
315
316 bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type);
317 if (IS_ERR(bdev))
318 return PTR_ERR(bdev);
319
320 if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
321 int mtdnr = MINOR(bdev->bd_dev);
322 close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE);
323 return logfs_get_sb_mtd(type, flags, mtdnr, mnt);
324 }
325
326 return logfs_get_sb_device(type, flags, NULL, bdev, &bd_devops, mnt);
327}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-23 02:37:40 -0500