| /* |
| * fs/logfs/dev_bdev.c - Device access methods for block devices |
| * |
| * As should be obvious for Linux kernel code, license is GPLv2 |
| * |
| * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> |
| */ |
| #include "logfs.h" |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/buffer_head.h> |
| #include <linux/gfp.h> |
| |
| #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) |
| |
| static void request_complete(struct bio *bio, int err) |
| { |
| complete((struct completion *)bio->bi_private); |
| } |
| |
| static int sync_request(struct page *page, struct block_device *bdev, int rw) |
| { |
| struct bio bio; |
| struct bio_vec bio_vec; |
| struct completion complete; |
| |
| bio_init(&bio); |
| bio.bi_io_vec = &bio_vec; |
| bio_vec.bv_page = page; |
| bio_vec.bv_len = PAGE_SIZE; |
| bio_vec.bv_offset = 0; |
| bio.bi_vcnt = 1; |
| bio.bi_idx = 0; |
| bio.bi_size = PAGE_SIZE; |
| bio.bi_bdev = bdev; |
| bio.bi_sector = page->index * (PAGE_SIZE >> 9); |
| init_completion(&complete); |
| bio.bi_private = &complete; |
| bio.bi_end_io = request_complete; |
| |
| submit_bio(rw, &bio); |
| wait_for_completion(&complete); |
| return test_bit(BIO_UPTODATE, &bio.bi_flags) ? 0 : -EIO; |
| } |
| |
| static int bdev_readpage(void *_sb, struct page *page) |
| { |
| struct super_block *sb = _sb; |
| struct block_device *bdev = logfs_super(sb)->s_bdev; |
| int err; |
| |
| err = sync_request(page, bdev, READ); |
| if (err) { |
| ClearPageUptodate(page); |
| SetPageError(page); |
| } else { |
| SetPageUptodate(page); |
| ClearPageError(page); |
| } |
| unlock_page(page); |
| return err; |
| } |
| |
| static DECLARE_WAIT_QUEUE_HEAD(wq); |
| |
| static void writeseg_end_io(struct bio *bio, int err) |
| { |
| const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; |
| struct super_block *sb = bio->bi_private; |
| struct logfs_super *super = logfs_super(sb); |
| struct page *page; |
| |
| BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ |
| BUG_ON(err); |
| BUG_ON(bio->bi_vcnt == 0); |
| do { |
| page = bvec->bv_page; |
| if (--bvec >= bio->bi_io_vec) |
| prefetchw(&bvec->bv_page->flags); |
| |
| end_page_writeback(page); |
| page_cache_release(page); |
| } while (bvec >= bio->bi_io_vec); |
| bio_put(bio); |
| if (atomic_dec_and_test(&super->s_pending_writes)) |
| wake_up(&wq); |
| } |
| |
| static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, |
| size_t nr_pages) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| struct address_space *mapping = super->s_mapping_inode->i_mapping; |
| struct bio *bio; |
| struct page *page; |
| struct request_queue *q = bdev_get_queue(sb->s_bdev); |
| unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9); |
| int i; |
| |
| if (max_pages > BIO_MAX_PAGES) |
| max_pages = BIO_MAX_PAGES; |
| bio = bio_alloc(GFP_NOFS, max_pages); |
| BUG_ON(!bio); |
| |
| for (i = 0; i < nr_pages; i++) { |
| if (i >= max_pages) { |
| /* Block layer cannot split bios :( */ |
| bio->bi_vcnt = i; |
| bio->bi_idx = 0; |
| bio->bi_size = i * PAGE_SIZE; |
| bio->bi_bdev = super->s_bdev; |
| bio->bi_sector = ofs >> 9; |
| bio->bi_private = sb; |
| bio->bi_end_io = writeseg_end_io; |
| atomic_inc(&super->s_pending_writes); |
| submit_bio(WRITE, bio); |
| |
| ofs += i * PAGE_SIZE; |
| index += i; |
| nr_pages -= i; |
| i = 0; |
| |
| bio = bio_alloc(GFP_NOFS, max_pages); |
| BUG_ON(!bio); |
| } |
| page = find_lock_page(mapping, index + i); |
| BUG_ON(!page); |
| bio->bi_io_vec[i].bv_page = page; |
| bio->bi_io_vec[i].bv_len = PAGE_SIZE; |
| bio->bi_io_vec[i].bv_offset = 0; |
| |
| BUG_ON(PageWriteback(page)); |
| set_page_writeback(page); |
| unlock_page(page); |
| } |
| bio->bi_vcnt = nr_pages; |
| bio->bi_idx = 0; |
| bio->bi_size = nr_pages * PAGE_SIZE; |
| bio->bi_bdev = super->s_bdev; |
| bio->bi_sector = ofs >> 9; |
| bio->bi_private = sb; |
| bio->bi_end_io = writeseg_end_io; |
| atomic_inc(&super->s_pending_writes); |
| submit_bio(WRITE, bio); |
| return 0; |
| } |
| |
| static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| int head; |
| |
| BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO); |
| |
| if (len == 0) { |
| /* This can happen when the object fit perfectly into a |
| * segment, the segment gets written per sync and subsequently |
| * closed. |
| */ |
| return; |
| } |
| head = ofs & (PAGE_SIZE - 1); |
| if (head) { |
| ofs -= head; |
| len += head; |
| } |
| len = PAGE_ALIGN(len); |
| __bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); |
| } |
| |
| |
| static void erase_end_io(struct bio *bio, int err) |
| { |
| const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| struct super_block *sb = bio->bi_private; |
| struct logfs_super *super = logfs_super(sb); |
| |
| BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ |
| BUG_ON(err); |
| BUG_ON(bio->bi_vcnt == 0); |
| bio_put(bio); |
| if (atomic_dec_and_test(&super->s_pending_writes)) |
| wake_up(&wq); |
| } |
| |
| static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index, |
| size_t nr_pages) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| struct bio *bio; |
| struct request_queue *q = bdev_get_queue(sb->s_bdev); |
| unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9); |
| int i; |
| |
| if (max_pages > BIO_MAX_PAGES) |
| max_pages = BIO_MAX_PAGES; |
| bio = bio_alloc(GFP_NOFS, max_pages); |
| BUG_ON(!bio); |
| |
| for (i = 0; i < nr_pages; i++) { |
| if (i >= max_pages) { |
| /* Block layer cannot split bios :( */ |
| bio->bi_vcnt = i; |
| bio->bi_idx = 0; |
| bio->bi_size = i * PAGE_SIZE; |
| bio->bi_bdev = super->s_bdev; |
| bio->bi_sector = ofs >> 9; |
| bio->bi_private = sb; |
| bio->bi_end_io = erase_end_io; |
| atomic_inc(&super->s_pending_writes); |
| submit_bio(WRITE, bio); |
| |
| ofs += i * PAGE_SIZE; |
| index += i; |
| nr_pages -= i; |
| i = 0; |
| |
| bio = bio_alloc(GFP_NOFS, max_pages); |
| BUG_ON(!bio); |
| } |
| bio->bi_io_vec[i].bv_page = super->s_erase_page; |
| bio->bi_io_vec[i].bv_len = PAGE_SIZE; |
| bio->bi_io_vec[i].bv_offset = 0; |
| } |
| bio->bi_vcnt = nr_pages; |
| bio->bi_idx = 0; |
| bio->bi_size = nr_pages * PAGE_SIZE; |
| bio->bi_bdev = super->s_bdev; |
| bio->bi_sector = ofs >> 9; |
| bio->bi_private = sb; |
| bio->bi_end_io = erase_end_io; |
| atomic_inc(&super->s_pending_writes); |
| submit_bio(WRITE, bio); |
| return 0; |
| } |
| |
| static int bdev_erase(struct super_block *sb, loff_t to, size_t len, |
| int ensure_write) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| |
| BUG_ON(to & (PAGE_SIZE - 1)); |
| BUG_ON(len & (PAGE_SIZE - 1)); |
| |
| if (super->s_flags & LOGFS_SB_FLAG_RO) |
| return -EROFS; |
| |
| if (ensure_write) { |
| /* |
| * Object store doesn't care whether erases happen or not. |
| * But for the journal they are required. Otherwise a scan |
| * can find an old commit entry and assume it is the current |
| * one, travelling back in time. |
| */ |
| do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT); |
| } |
| |
| return 0; |
| } |
| |
| static void bdev_sync(struct super_block *sb) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| |
| wait_event(wq, atomic_read(&super->s_pending_writes) == 0); |
| } |
| |
| static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| struct address_space *mapping = super->s_mapping_inode->i_mapping; |
| filler_t *filler = bdev_readpage; |
| |
| *ofs = 0; |
| return read_cache_page(mapping, 0, filler, sb); |
| } |
| |
| static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs) |
| { |
| struct logfs_super *super = logfs_super(sb); |
| struct address_space *mapping = super->s_mapping_inode->i_mapping; |
| filler_t *filler = bdev_readpage; |
| u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000; |
| pgoff_t index = pos >> PAGE_SHIFT; |
| |
| *ofs = pos; |
| return read_cache_page(mapping, index, filler, sb); |
| } |
| |
| static int bdev_write_sb(struct super_block *sb, struct page *page) |
| { |
| struct block_device *bdev = logfs_super(sb)->s_bdev; |
| |
| /* Nothing special to do for block devices. */ |
| return sync_request(page, bdev, WRITE); |
| } |
| |
| static void bdev_put_device(struct logfs_super *s) |
| { |
| blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
| } |
| |
| static int bdev_can_write_buf(struct super_block *sb, u64 ofs) |
| { |
| return 0; |
| } |
| |
| static const struct logfs_device_ops bd_devops = { |
| .find_first_sb = bdev_find_first_sb, |
| .find_last_sb = bdev_find_last_sb, |
| .write_sb = bdev_write_sb, |
| .readpage = bdev_readpage, |
| .writeseg = bdev_writeseg, |
| .erase = bdev_erase, |
| .can_write_buf = bdev_can_write_buf, |
| .sync = bdev_sync, |
| .put_device = bdev_put_device, |
| }; |
| |
| int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type, |
| const char *devname) |
| { |
| struct block_device *bdev; |
| |
| bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL, |
| type); |
| if (IS_ERR(bdev)) |
| return PTR_ERR(bdev); |
| |
| if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { |
| int mtdnr = MINOR(bdev->bd_dev); |
| blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); |
| return logfs_get_sb_mtd(p, mtdnr); |
| } |
| |
| p->s_bdev = bdev; |
| p->s_mtd = NULL; |
| p->s_devops = &bd_devops; |
| return 0; |
| } |