/* * 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>#include <linux/prefetch.h> #define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) static int sync_request(struct page *page, struct block_device *bdev, int op){	struct bio bio;	struct bio_vec bio_vec; 	bio_init(&bio);	bio.bi_max_vecs = 1;	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_bdev = bdev;	bio.bi_iter.bi_sector = page->index * (PAGE_SIZE >> 9);	bio.bi_iter.bi_size = PAGE_SIZE;	bio_set_op_attrs(&bio, op, 0); 	return submit_bio_wait(&bio);} 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){	struct bio_vec *bvec;	int i;	struct super_block *sb = bio->bi_private;	struct logfs_super *super = logfs_super(sb); 	BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */ 	bio_for_each_segment_all(bvec, bio, i) {		end_page_writeback(bvec->bv_page);		put_page(bvec->bv_page);	}	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;	unsigned int max_pages;	int i; 	max_pages = min_t(size_t, nr_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_iter.bi_size = i * PAGE_SIZE;			bio->bi_bdev = super->s_bdev;			bio->bi_iter.bi_sector = ofs >> 9;			bio->bi_private = sb;			bio->bi_end_io = writeseg_end_io;			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);			atomic_inc(&super->s_pending_writes);			submit_bio(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_iter.bi_size = nr_pages * PAGE_SIZE;	bio->bi_bdev = super->s_bdev;	bio->bi_iter.bi_sector = ofs >> 9;	bio->bi_private = sb;	bio->bi_end_io = writeseg_end_io;	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);	atomic_inc(&super->s_pending_writes);	submit_bio(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){ 	struct super_block *sb = bio->bi_private; 	struct logfs_super *super = logfs_super(sb);  	BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */ 	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;	unsigned int max_pages;	int i; 	max_pages = min_t(size_t, nr_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_iter.bi_size = i * PAGE_SIZE;			bio->bi_bdev = super->s_bdev;			bio->bi_iter.bi_sector = ofs >> 9;			bio->bi_private = sb;			bio->bi_end_io = erase_end_io;			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);			atomic_inc(&super->s_pending_writes);			submit_bio(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_iter.bi_size = nr_pages * PAGE_SIZE;	bio->bi_bdev = super->s_bdev;	bio->bi_iter.bi_sector = ofs >> 9;	bio->bi_private = sb;	bio->bi_end_io = erase_end_io;	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);	atomic_inc(&super->s_pending_writes);	submit_bio(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;}