C++ ClearPageUptodate函數代碼示例

/**
 * invalidate_inode_pages2 - remove all unmapped pages from an address_space
 * @mapping - the address_space
 *
 * invalidate_inode_pages2() is like truncate_inode_pages(), except for the case
 * where the page is seen to be mapped into process pagetables.  In that case,
 * the page is marked clean but is left attached to its address_space.
 *
 * The page is also marked not uptodate so that a subsequent pagefault will
 * perform I/O to bringthe page's contents back into sync with its backing
 * store.
 *
 * FIXME: invalidate_inode_pages2() is probably trivially livelockable.
 */
void invalidate_inode_pages2(struct address_space *mapping)
{
	struct pagevec pvec;
	pgoff_t next = 0;
	int i;

	pagevec_init(&pvec, 0);
	while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			lock_page(page);
			if (page->mapping == mapping) {	/* truncate race? */
				wait_on_page_writeback(page);
				next = page->index + 1;
				if (page_mapped(page)) {
					clear_page_dirty(page);
					ClearPageUptodate(page);
				} else {
					if (!invalidate_complete_page(mapping,
								      page)) {
						clear_page_dirty(page);
						ClearPageUptodate(page);
					}
				}
			}
			unlock_page(page);
		}
		pagevec_release(&pvec);
		cond_resched();
	}
}

/*
 * I/O completion handler for multipage BIOs.
 *
 * The mpage code never puts partial pages into a BIO (except for end-of-file).
 * If a page does not map to a contiguous run of blocks then it simply falls
 * back to block_read_full_page().
 *
 * Why is this?  If a page's completion depends on a number of different BIOs
 * which can complete in any order (or at the same time) then determining the
 * status of that page is hard.  See end_buffer_async_read() for the details.
 * There is no point in duplicating all that complexity.
 */
static void mpage_end_io_read(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;

	do {
		struct page *page = bvec->bv_page;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);

		if (uptodate) {
			SetPageUptodate(page);
		} else {
			ClearPageUptodate(page);
			SetPageError(page);
		}
		if (bio_flagged(bio, BIO_BAIO)) {
			struct ba_iocb *baiocb =
				(struct ba_iocb *)bio->bi_private2;
		       	BUG_ON(!PageBaio(page));
			ClearPageBaio(page);
			if (!uptodate)
				baiocb->io_error = -EIO;
			baiocb->result += bvec->bv_len;
			baiocb_put(baiocb);
		}
		unlock_page(page);
	} while (bvec >= bio->bi_io_vec);
	bio_put(bio);
}

/**
 * nilfs_copy_buffer -- copy buffer data and flags
 * @dbh: destination buffer
 * @sbh: source buffer
 */
void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
{
	void *kaddr0, *kaddr1;
	unsigned long bits;
	struct page *spage = sbh->b_page, *dpage = dbh->b_page;
	struct buffer_head *bh;

	kaddr0 = kmap_atomic(spage);
	kaddr1 = kmap_atomic(dpage);
	memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
	kunmap_atomic(kaddr1);
	kunmap_atomic(kaddr0);

	dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
	dbh->b_blocknr = sbh->b_blocknr;
	dbh->b_bdev = sbh->b_bdev;

	bh = dbh;
	bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
	while ((bh = bh->b_this_page) != dbh) {
		lock_buffer(bh);
		bits &= bh->b_state;
		unlock_buffer(bh);
	}
	if (bits & BIT(BH_Uptodate))
		SetPageUptodate(dpage);
	else
		ClearPageUptodate(dpage);
	if (bits & BIT(BH_Mapped))
		SetPageMappedToDisk(dpage);
	else
		ClearPageMappedToDisk(dpage);
}

static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)
{
    struct super_block *sb = sdp->sd_vfs;
    struct gfs2_sb *p;
    struct page *page;
    struct bio *bio;

    page = alloc_page(GFP_NOFS);
    if (unlikely(!page))
        return -ENOBUFS;

    ClearPageUptodate(page);
    ClearPageDirty(page);
    lock_page(page);

    bio = bio_alloc(GFP_NOFS, 1);
    bio->bi_sector = sector * (sb->s_blocksize >> 9);
    bio->bi_bdev = sb->s_bdev;
    bio_add_page(bio, page, PAGE_SIZE, 0);

    bio->bi_end_io = end_bio_io_page;
    bio->bi_private = page;
    submit_bio(READ_SYNC | REQ_META, bio);
    wait_on_page_locked(page);
    bio_put(bio);
    if (!PageUptodate(page)) {
        __free_page(page);
        return -EIO;
    }
    p = kmap(page);
    gfs2_sb_in(sdp, p);
    kunmap(page);
    __free_page(page);
    return gfs2_check_sb(sdp, silent);
}

/*
 * It only removes the dentry from the dentry page,corresponding name
 * entry in name page does not need to be touched during deletion.
 */
void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
						struct inode *inode)
{
	struct	f2fs_dentry_block *dentry_blk;
	unsigned int bit_pos;
	struct address_space *mapping = page->mapping;
	struct inode *dir = mapping->host;
	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
	void *kaddr = page_address(page);
	int i;

	lock_page(page);
	wait_on_page_writeback(page);

	dentry_blk = (struct f2fs_dentry_block *)kaddr;
	bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
	for (i = 0; i < slots; i++)
		test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);

	/* Let's check and deallocate this dentry page */
	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
			NR_DENTRY_IN_BLOCK,
			0);
	kunmap(page); /* kunmap - pair of f2fs_find_entry */
	set_page_dirty(page);

	dir->i_ctime = dir->i_mtime = CURRENT_TIME;

	if (inode && S_ISDIR(inode->i_mode)) {
		drop_nlink(dir);
		update_inode_page(dir);
	} else {
		mark_inode_dirty(dir);
	}

	if (inode) {
		inode->i_ctime = CURRENT_TIME;
		drop_nlink(inode);
		if (S_ISDIR(inode->i_mode)) {
			drop_nlink(inode);
			i_size_write(inode, 0);
		}
		update_inode_page(inode);

		if (inode->i_nlink == 0)
			add_orphan_inode(sbi, inode->i_ino);
		else
			release_orphan_inode(sbi);
	}

	if (bit_pos == NR_DENTRY_IN_BLOCK) {
		truncate_hole(dir, page->index, page->index + 1);
		clear_page_dirty_for_io(page);
		ClearPageUptodate(page);
		dec_page_count(sbi, F2FS_DIRTY_DENTS);
		inode_dec_dirty_dents(dir);
	}
	f2fs_put_page(page, 1);
}

static void f2fs_read_end_io(struct bio *bio)
{
    struct bio_vec *bvec;
    int i;

    if (f2fs_bio_encrypted(bio)) {
        if (bio->bi_error) {
            f2fs_release_crypto_ctx(bio->bi_private);
        } else {
            f2fs_end_io_crypto_work(bio->bi_private, bio);
            return;
        }
    }

    bio_for_each_segment_all(bvec, bio, i) {
        struct page *page = bvec->bv_page;

        if (!bio->bi_error) {
            SetPageUptodate(page);
        } else {
            ClearPageUptodate(page);
            SetPageError(page);
        }
        unlock_page(page);
    }
    bio_put(bio);
}

/**
 * ecryptfs_writepage
 * @page: Page that is locked before this call is made
 *
 * Returns zero on success; non-zero otherwise
 *
 * This is where we encrypt the data and pass the encrypted data to
 * the lower filesystem.  In OpenPGP-compatible mode, we operate on
 * entire underlying packets.
 */
static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
{
	int rc;

	// WTL_EDM_START
	/* MDM 3.1 START */
	struct inode *inode;
	struct ecryptfs_crypt_stat *crypt_stat;

	inode = page->mapping->host;
	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
		size_t size;
		loff_t file_size = i_size_read(inode);
		pgoff_t end_page_index = file_size >> PAGE_CACHE_SHIFT;
		if (end_page_index < page->index)
			size = 0;
		else if (end_page_index == page->index)
			size = file_size & ~PAGE_CACHE_MASK;
		else
			size = PAGE_CACHE_SIZE;

		rc = ecryptfs_write_lower_page_segment(inode, page, 0,
						       size);
		if (unlikely(rc)) {
			ecryptfs_printk(KERN_WARNING, "Error write ""page (upper index [0x%.16lx])\n", page->index);
			ClearPageUptodate(page);
		} else
			SetPageUptodate(page);
		goto out;
	}

/* completion handler for BIO writes */
static int bi_write_complete(struct bio *bio, unsigned int bytes_done, int error)
{
    const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
    struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;

    if (bio->bi_size)
        return 1;

    if(!uptodate)
        err("bi_write_complete: not uptodate\n");

    do {
        struct page *page = bvec->bv_page;
        DEBUG(3, "Cleaning up page %ld\n", page->index);
        if (--bvec >= bio->bi_io_vec)
            prefetchw(&bvec->bv_page->flags);

        if (uptodate) {
            SetPageUptodate(page);
        } else {
            ClearPageUptodate(page);
            SetPageError(page);
        }
        ClearPageDirty(page);
        unlock_page(page);
        page_cache_release(page);
    } while (bvec >= bio->bi_io_vec);

    complete((struct completion*)bio->bi_private);
    return 0;
}

/*
 * I/O completion handler for multipage BIOs.
 *
 * The mpage code never puts partial pages into a BIO (except for end-of-file).
 * If a page does not map to a contiguous run of blocks then it simply falls
 * back to block_read_full_page().
 *
 * Why is this?  If a page's completion depends on a number of different BIOs
 * which can complete in any order (or at the same time) then determining the
 * status of that page is hard.  See end_buffer_async_read() for the details.
 * There is no point in duplicating all that complexity.
 */
static void mpage_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;

	do {
		struct page *page = bvec->bv_page;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);
		if (bio_data_dir(bio) == READ) {
			if (uptodate) {
				SetPageUptodate(page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
			unlock_page(page);
		} else { /* bio_data_dir(bio) == WRITE */
			if (!uptodate) {
				SetPageError(page);
				if (page->mapping)
					set_bit(AS_EIO, &page->mapping->flags);
			}
			end_page_writeback(page);
		}
	} while (bvec >= bio->bi_io_vec);
	bio_put(bio);
}

/*
 * Populate a page with data for the Linux page cache.  This function is
 * only used to support mmap(2).  There will be an identical copy of the
 * data in the ARC which is kept up to date via .write() and .writepage().
 *
 * Current this function relies on zpl_read_common() and the O_DIRECT
 * flag to read in a page.  This works but the more correct way is to
 * update zfs_fillpage() to be Linux friendly and use that interface.
 */
static int
zpl_readpage(struct file *filp, struct page *pp)
{
	struct inode *ip;
	struct page *pl[1];
	int error = 0;

	ASSERT(PageLocked(pp));
	ip = pp->mapping->host;
	pl[0] = pp;

	error = -zfs_getpage(ip, pl, 1);

	if (error) {
		SetPageError(pp);
		ClearPageUptodate(pp);
	} else {
		ClearPageError(pp);
		SetPageUptodate(pp);
		flush_dcache_page(pp);
	}

	unlock_page(pp);
	return (error);
}

static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	unsigned char *pg_buf;
	int ret;

;

	BUG_ON(!PageLocked(pg));

	pg_buf = kmap(pg);
	/* FIXME: Can kmap fail? */

	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);

	if (ret) {
		ClearPageUptodate(pg);
		SetPageError(pg);
	} else {
		SetPageUptodate(pg);
		ClearPageError(pg);
	}

	flush_dcache_page(pg);
	kunmap(pg);

;
	return ret;
}

/*
 * I/O completion handler for multipage BIOs.
 *
 * The mpage code never puts partial pages into a BIO (except for end-of-file).
 * If a page does not map to a contiguous run of blocks then it simply falls
 * back to block_read_full_page().
 *
 * Why is this?  If a page's completion depends on a number of different BIOs
 * which can complete in any order (or at the same time) then determining the
 * status of that page is hard.  See end_buffer_async_read() for the details.
 * There is no point in duplicating all that complexity.
 */
static void mpage_end_io(struct bio *bio)
{
	struct bio_vec *bv;
	int i;
	struct bvec_iter_all iter_all;

	if (ext4_bio_encrypted(bio)) {
		if (bio->bi_status) {
			fscrypt_release_ctx(bio->bi_private);
		} else {
			fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
			return;
		}
	}
	bio_for_each_segment_all(bv, bio, i, iter_all) {
		struct page *page = bv->bv_page;

		if (!bio->bi_status) {
			SetPageUptodate(page);
		} else {
			ClearPageUptodate(page);
			SetPageError(page);
		}
		unlock_page(page);
	}

	bio_put(bio);
}

void nilfs_clear_dirty_pages(struct address_space *mapping)
{
	struct pagevec pvec;
	unsigned int i;
	pgoff_t index = 0;

	pagevec_init(&pvec, 0);

	while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
				  PAGEVEC_SIZE)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];
			struct buffer_head *bh, *head;

			lock_page(page);
			ClearPageUptodate(page);
			ClearPageMappedToDisk(page);
			bh = head = page_buffers(page);
			do {
				lock_buffer(bh);
				clear_buffer_dirty(bh);
				clear_buffer_nilfs_volatile(bh);
				clear_buffer_uptodate(bh);
				clear_buffer_mapped(bh);
				unlock_buffer(bh);
				bh = bh->b_this_page;
			} while (bh != head);

			__nilfs_clear_page_dirty(page);
			unlock_page(page);
		}
		pagevec_release(&pvec);
		cond_resched();
	}
}

static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	unsigned char *pg_buf;
	int ret;

	jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
		  __func__, inode->i_ino, pg->index << PAGE_SHIFT);

	BUG_ON(!PageLocked(pg));

	pg_buf = kmap(pg);
	/* FIXME: Can kmap fail? */

	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
				     PAGE_SIZE);

	if (ret) {
		ClearPageUptodate(pg);
		SetPageError(pg);
	} else {
		SetPageUptodate(pg);
		ClearPageError(pg);
	}

	flush_dcache_page(pg);
	kunmap(pg);

	jffs2_dbg(2, "readpage finished\n");
	return ret;
}

int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	unsigned char *pg_buf;
	int ret;

	D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));

	if (!PageLocked(pg))
                PAGE_BUG(pg);

	pg_buf = kmap(pg);
	/* FIXME: Can kmap fail? */

	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);

	if (ret) {
		ClearPageUptodate(pg);
		SetPageError(pg);
	} else {
		SetPageUptodate(pg);
		ClearPageError(pg);
	}

	flush_dcache_page(pg);
	kunmap(pg);

	D2(printk(KERN_DEBUG "readpage finished\n"));
	return 0;
}