From 5db53f3e80dee2d9dff5e534f9e9fe1db17c9936 Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Fri, 20 Nov 2009 20:13:39 +0100 Subject: [LogFS] add new flash file system This is a new flash file system. See Documentation/filesystems/logfs.txt Signed-off-by: Joern Engel --- fs/logfs/dev_bdev.c | 263 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 263 insertions(+) create mode 100644 fs/logfs/dev_bdev.c (limited to 'fs/logfs/dev_bdev.c') diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c new file mode 100644 index 000000000000..58a057b6e1af --- /dev/null +++ b/fs/logfs/dev_bdev.c @@ -0,0 +1,263 @@ +/* + * 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 + */ +#include "logfs.h" +#include +#include +#include + +#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); + } 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; + + bio = bio_alloc(GFP_NOFS, max_pages); + BUG_ON(!bio); /* FIXME: handle this */ + + 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 int bdev_erase(struct super_block *sb, loff_t to, size_t len) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct page *page; + pgoff_t index = to >> PAGE_SHIFT; + int i, nr_pages = len >> PAGE_SHIFT; + + BUG_ON(to & (PAGE_SIZE - 1)); + BUG_ON(len & (PAGE_SIZE - 1)); + + if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) + return -EROFS; + + for (i = 0; i < nr_pages; i++) { + page = find_get_page(mapping, index + i); + if (page) { + memset(page_address(page), 0xFF, PAGE_SIZE); + page_cache_release(page); + } + } + 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); +} -- cgit v1.2.2 From 9421502b4fc894cc477be8fc49776830e37ca157 Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Thu, 4 Mar 2010 21:30:58 +0100 Subject: [LogFS] Fix bdev erases Erases for block devices were always just emulated by writing 0xff. Some time back the write was removed and only the page cache was changed to 0xff. Superficialy a good idea with two problems: 1. Touching the page cache isn't necessary either. 2. However, writing out 0xff _is_ necessary for the journal. As the journal is scanned linearly, an old non-overwritten commit entry can be used on next mount and cause havoc. This should fix both aspects. --- fs/logfs/dev_bdev.c | 88 +++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 76 insertions(+), 12 deletions(-) (limited to 'fs/logfs/dev_bdev.c') diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c index 58a057b6e1af..9718c22f186d 100644 --- a/fs/logfs/dev_bdev.c +++ b/fs/logfs/dev_bdev.c @@ -167,27 +167,91 @@ static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len) generic_unplug_device(bdev_get_queue(logfs_super(sb)->s_bdev)); } -static int bdev_erase(struct super_block *sb, loff_t to, size_t len) + +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; + + bio = bio_alloc(GFP_NOFS, max_pages); + BUG_ON(!bio); /* FIXME: handle this */ + + 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); - struct address_space *mapping = super->s_mapping_inode->i_mapping; - struct page *page; - pgoff_t index = to >> PAGE_SHIFT; - int i, nr_pages = len >> PAGE_SHIFT; BUG_ON(to & (PAGE_SIZE - 1)); BUG_ON(len & (PAGE_SIZE - 1)); - if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) + if (super->s_flags & LOGFS_SB_FLAG_RO) return -EROFS; - for (i = 0; i < nr_pages; i++) { - page = find_get_page(mapping, index + i); - if (page) { - memset(page_address(page), 0xFF, PAGE_SIZE); - page_cache_release(page); - } + 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; } -- cgit v1.2.2