~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/logfs/dev_bdev.c

Version: ~ [ linux-5.2 ] ~ [ linux-5.1.16 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.57 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.132 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.184 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.184 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.69 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 #include <linux/gfp.h>
 13 #include <linux/prefetch.h>
 14 
 15 #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1))
 16 
 17 static int sync_request(struct page *page, struct block_device *bdev, int rw)
 18 {
 19         struct bio bio;
 20         struct bio_vec bio_vec;
 21 
 22         bio_init(&bio);
 23         bio.bi_max_vecs = 1;
 24         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;
 29         bio.bi_bdev = bdev;
 30         bio.bi_iter.bi_sector = page->index * (PAGE_SIZE >> 9);
 31         bio.bi_iter.bi_size = PAGE_SIZE;
 32 
 33         return submit_bio_wait(rw, &bio);
 34 }
 35 
 36 static 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 
 54 static DECLARE_WAIT_QUEUE_HEAD(wq);
 55 
 56 static void writeseg_end_io(struct bio *bio)
 57 {
 58         struct bio_vec *bvec;
 59         int i;
 60         struct super_block *sb = bio->bi_private;
 61         struct logfs_super *super = logfs_super(sb);
 62 
 63         BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */
 64 
 65         bio_for_each_segment_all(bvec, bio, i) {
 66                 end_page_writeback(bvec->bv_page);
 67                 page_cache_release(bvec->bv_page);
 68         }
 69         bio_put(bio);
 70         if (atomic_dec_and_test(&super->s_pending_writes))
 71                 wake_up(&wq);
 72 }
 73 
 74 static 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;
 81         unsigned int max_pages;
 82         int i;
 83 
 84         max_pages = min(nr_pages, BIO_MAX_PAGES);
 85 
 86         bio = bio_alloc(GFP_NOFS, max_pages);
 87         BUG_ON(!bio);
 88 
 89         for (i = 0; i < nr_pages; i++) {
 90                 if (i >= max_pages) {
 91                         /* Block layer cannot split bios :( */
 92                         bio->bi_vcnt = i;
 93                         bio->bi_iter.bi_size = i * PAGE_SIZE;
 94                         bio->bi_bdev = super->s_bdev;
 95                         bio->bi_iter.bi_sector = ofs >> 9;
 96                         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;
120         bio->bi_iter.bi_size = nr_pages * PAGE_SIZE;
121         bio->bi_bdev = super->s_bdev;
122         bio->bi_iter.bi_sector = ofs >> 9;
123         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 
130 static 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);
151 }
152 
153 
154 static void erase_end_io(struct bio *bio)
155 { 
156         struct super_block *sb = bio->bi_private; 
157         struct logfs_super *super = logfs_super(sb); 
158 
159         BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */ 
160         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 
166 static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
167                 size_t nr_pages)
168 {
169         struct logfs_super *super = logfs_super(sb);
170         struct bio *bio;
171         unsigned int max_pages;
172         int i;
173 
174         max_pages = min(nr_pages, BIO_MAX_PAGES);
175 
176         bio = bio_alloc(GFP_NOFS, max_pages);
177         BUG_ON(!bio);
178 
179         for (i = 0; i < nr_pages; i++) {
180                 if (i >= max_pages) {
181                         /* Block layer cannot split bios :( */
182                         bio->bi_vcnt = i;
183                         bio->bi_iter.bi_size = i * PAGE_SIZE;
184                         bio->bi_bdev = super->s_bdev;
185                         bio->bi_iter.bi_sector = ofs >> 9;
186                         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;
204         bio->bi_iter.bi_size = nr_pages * PAGE_SIZE;
205         bio->bi_bdev = super->s_bdev;
206         bio->bi_iter.bi_sector = ofs >> 9;
207         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 
214 static 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);
218 
219         BUG_ON(to & (PAGE_SIZE - 1));
220         BUG_ON(len & (PAGE_SIZE - 1));
221 
222         if (super->s_flags & LOGFS_SB_FLAG_RO)
223                 return -EROFS;
224 
225         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);
233         }
234 
235         return 0;
236 }
237 
238 static 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 
245 static 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 
255 static 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 
267 static 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 
275 static void bdev_put_device(struct logfs_super *s)
276 {
277         blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
278 }
279 
280 static int bdev_can_write_buf(struct super_block *sb, u64 ofs)
281 {
282         return 0;
283 }
284 
285 static 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,
292         .can_write_buf  = bdev_can_write_buf,
293         .sync           = bdev_sync,
294         .put_device     = bdev_put_device,
295 };
296 
297 int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type,
298                 const char *devname)
299 {
300         struct block_device *bdev;
301 
302         bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
303                                   type);
304         if (IS_ERR(bdev))
305                 return PTR_ERR(bdev);
306 
307         if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
308                 int mtdnr = MINOR(bdev->bd_dev);
309                 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
310                 return logfs_get_sb_mtd(p, mtdnr);
311         }
312 
313         p->s_bdev = bdev;
314         p->s_mtd = NULL;
315         p->s_devops = &bd_devops;
316         return 0;
317 }
318 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp