333 lines
8.4 KiB
C
333 lines
8.4 KiB
C
/*
|
|
* 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);
|
|
generic_unplug_device(bdev_get_queue(bdev));
|
|
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);
|
|
generic_unplug_device(bdev_get_queue(logfs_super(sb)->s_bdev));
|
|
}
|
|
|
|
|
|
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 super_block *sb)
|
|
{
|
|
close_bdev_exclusive(logfs_super(sb)->s_bdev, FMODE_READ|FMODE_WRITE);
|
|
}
|
|
|
|
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,
|
|
.sync = bdev_sync,
|
|
.put_device = bdev_put_device,
|
|
};
|
|
|
|
int logfs_get_sb_bdev(struct file_system_type *type, int flags,
|
|
const char *devname, struct vfsmount *mnt)
|
|
{
|
|
struct block_device *bdev;
|
|
|
|
bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type);
|
|
if (IS_ERR(bdev))
|
|
return PTR_ERR(bdev);
|
|
|
|
if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
|
|
int mtdnr = MINOR(bdev->bd_dev);
|
|
close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE);
|
|
return logfs_get_sb_mtd(type, flags, mtdnr, mnt);
|
|
}
|
|
|
|
return logfs_get_sb_device(type, flags, NULL, bdev, &bd_devops, mnt);
|
|
}
|