jfs_metapage.c

linux 内核源代码

			set_page_writeback(page);
			inc_io(page);
		}
		xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
		pblock = metapage_get_blocks(inode, lblock, &xlen);
		if (!pblock) {
			/* Need better error handling */
			printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
			dec_io(page, last_write_complete);
			continue;
		}
		set_bit(META_io, &mp->flag);
		len = min(xlen, (uint) JFS_SBI(inode->i_sb)->nbperpage);

		bio = bio_alloc(GFP_NOFS, 1);
		bio->bi_bdev = inode->i_sb->s_bdev;
		bio->bi_sector = pblock << (inode->i_blkbits - 9);
		bio->bi_end_io = metapage_write_end_io;
		bio->bi_private = page;

		/* Don't call bio_add_page yet, we may add to this vec */
		bio_offset = offset;
		bio_bytes = len << inode->i_blkbits;

		xlen -= len;
		next_block = lblock + len;
	}
	if (bio) {
		if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
				goto add_failed;
		if (!bio->bi_size)
			goto dump_bio;

		submit_bio(WRITE, bio);
	}
	if (redirty)
		redirty_page_for_writepage(wbc, page);

	unlock_page(page);

	return 0;
add_failed:
	/* We should never reach here, since we're only adding one vec */
	printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
	goto skip;
dump_bio:
	print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
		       4, bio, sizeof(*bio), 0);
skip:
	bio_put(bio);
	unlock_page(page);
	dec_io(page, last_write_complete);

	return -EIO;
}

static int metapage_readpage(struct file *fp, struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct bio *bio = NULL;
	unsigned int block_offset;
	unsigned int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
	sector_t page_start;	/* address of page in fs blocks */
	sector_t pblock;
	unsigned int xlen;
	unsigned int len;
	unsigned int offset;

	BUG_ON(!PageLocked(page));
	page_start = (sector_t)page->index <<
		     (PAGE_CACHE_SHIFT - inode->i_blkbits);

	block_offset = 0;
	while (block_offset < blocks_per_page) {
		xlen = blocks_per_page - block_offset;
		pblock = metapage_get_blocks(inode, page_start + block_offset,
					     &xlen);
		if (pblock) {
			if (!PagePrivate(page))
				insert_metapage(page, NULL);
			inc_io(page);
			if (bio)
				submit_bio(READ, bio);

			bio = bio_alloc(GFP_NOFS, 1);
			bio->bi_bdev = inode->i_sb->s_bdev;
			bio->bi_sector = pblock << (inode->i_blkbits - 9);
			bio->bi_end_io = metapage_read_end_io;
			bio->bi_private = page;
			len = xlen << inode->i_blkbits;
			offset = block_offset << inode->i_blkbits;
			if (bio_add_page(bio, page, len, offset) < len)
				goto add_failed;
			block_offset += xlen;
		} else
			block_offset++;
	}
	if (bio)
		submit_bio(READ, bio);
	else
		unlock_page(page);

	return 0;

add_failed:
	printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
	bio_put(bio);
	dec_io(page, last_read_complete);
	return -EIO;
}

static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
{
	struct metapage *mp;
	int ret = 1;
	unsigned int offset;

	for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
		mp = page_to_mp(page, offset);

		if (!mp)
			continue;

		jfs_info("metapage_releasepage: mp = 0x%p", mp);
		if (mp->count || mp->nohomeok ||
		    test_bit(META_dirty, &mp->flag)) {
			jfs_info("count = %ld, nohomeok = %d", mp->count,
				 mp->nohomeok);
			ret = 0;
			continue;
		}
		if (mp->lsn)
			remove_from_logsync(mp);
		remove_metapage(page, mp);
		INCREMENT(mpStat.pagefree);
		free_metapage(mp);
	}
	return ret;
}

static void metapage_invalidatepage(struct page *page, unsigned long offset)
{
	BUG_ON(offset);

	BUG_ON(PageWriteback(page));

	metapage_releasepage(page, 0);
}

const struct address_space_operations jfs_metapage_aops = {
	.readpage	= metapage_readpage,
	.writepage	= metapage_writepage,
	.sync_page	= block_sync_page,
	.releasepage	= metapage_releasepage,
	.invalidatepage	= metapage_invalidatepage,
	.set_page_dirty	= __set_page_dirty_nobuffers,
};

struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
				unsigned int size, int absolute,
				unsigned long new)
{
	int l2BlocksPerPage;
	int l2bsize;
	struct address_space *mapping;
	struct metapage *mp = NULL;
	struct page *page;
	unsigned long page_index;
	unsigned long page_offset;

	jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
		 inode->i_ino, lblock, absolute);

	l2bsize = inode->i_blkbits;
	l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
	page_index = lblock >> l2BlocksPerPage;
	page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
	if ((page_offset + size) > PAGE_CACHE_SIZE) {
		jfs_err("MetaData crosses page boundary!!");
		jfs_err("lblock = %lx, size  = %d", lblock, size);
		dump_stack();
		return NULL;
	}
	if (absolute)
		mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
	else {
		/*
		 * If an nfs client tries to read an inode that is larger
		 * than any existing inodes, we may try to read past the
		 * end of the inode map
		 */
		if ((lblock << inode->i_blkbits) >= inode->i_size)
			return NULL;
		mapping = inode->i_mapping;
	}

	if (new && (PSIZE == PAGE_CACHE_SIZE)) {
		page = grab_cache_page(mapping, page_index);
		if (!page) {
			jfs_err("grab_cache_page failed!");
			return NULL;
		}
		SetPageUptodate(page);
	} else {
		page = read_mapping_page(mapping, page_index, NULL);
		if (IS_ERR(page) || !PageUptodate(page)) {
			jfs_err("read_mapping_page failed!");
			return NULL;
		}
		lock_page(page);
	}

	mp = page_to_mp(page, page_offset);
	if (mp) {
		if (mp->logical_size != size) {
			jfs_error(inode->i_sb,
				  "__get_metapage: mp->logical_size != size");
			jfs_err("logical_size = %d, size = %d",
				mp->logical_size, size);
			dump_stack();
			goto unlock;
		}
		mp->count++;
		lock_metapage(mp);
		if (test_bit(META_discard, &mp->flag)) {
			if (!new) {
				jfs_error(inode->i_sb,
					  "__get_metapage: using a "
					  "discarded metapage");
				discard_metapage(mp);
				goto unlock;
			}
			clear_bit(META_discard, &mp->flag);
		}
	} else {
		INCREMENT(mpStat.pagealloc);
		mp = alloc_metapage(GFP_NOFS);
		mp->page = page;
		mp->flag = 0;
		mp->xflag = COMMIT_PAGE;
		mp->count = 1;
		mp->nohomeok = 0;
		mp->logical_size = size;
		mp->data = page_address(page) + page_offset;
		mp->index = lblock;
		if (unlikely(insert_metapage(page, mp))) {
			free_metapage(mp);
			goto unlock;
		}
		lock_metapage(mp);
	}

	if (new) {
		jfs_info("zeroing mp = 0x%p", mp);
		memset(mp->data, 0, PSIZE);
	}

	unlock_page(page);
	jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
	return mp;

unlock:
	unlock_page(page);
	return NULL;
}

void grab_metapage(struct metapage * mp)
{
	jfs_info("grab_metapage: mp = 0x%p", mp);
	page_cache_get(mp->page);
	lock_page(mp->page);
	mp->count++;
	lock_metapage(mp);
	unlock_page(mp->page);
}

void force_metapage(struct metapage *mp)
{
	struct page *page = mp->page;
	jfs_info("force_metapage: mp = 0x%p", mp);
	set_bit(META_forcewrite, &mp->flag);
	clear_bit(META_sync, &mp->flag);
	page_cache_get(page);
	lock_page(page);
	set_page_dirty(page);
	write_one_page(page, 1);
	clear_bit(META_forcewrite, &mp->flag);
	page_cache_release(page);
}

void hold_metapage(struct metapage *mp)
{
	lock_page(mp->page);
}

void put_metapage(struct metapage *mp)
{
	if (mp->count || mp->nohomeok) {
		/* Someone else will release this */
		unlock_page(mp->page);
		return;
	}
	page_cache_get(mp->page);
	mp->count++;
	lock_metapage(mp);
	unlock_page(mp->page);
	release_metapage(mp);
}

void release_metapage(struct metapage * mp)
{
	struct page *page = mp->page;
	jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);

	BUG_ON(!page);

	lock_page(page);
	unlock_metapage(mp);

	assert(mp->count);
	if (--mp->count || mp->nohomeok) {
		unlock_page(page);
		page_cache_release(page);
		return;
	}

	if (test_bit(META_dirty, &mp->flag)) {
		set_page_dirty(page);
		if (test_bit(META_sync, &mp->flag)) {
			clear_bit(META_sync, &mp->flag);
			write_one_page(page, 1);
			lock_page(page); /* write_one_page unlocks the page */
		}
	} else if (mp->lsn)	/* discard_metapage doesn't remove it */
		remove_from_logsync(mp);

	/* Try to keep metapages from using up too much memory */
	drop_metapage(page, mp);

	unlock_page(page);
	page_cache_release(page);
}

void __invalidate_metapages(struct inode *ip, s64 addr, int len)
{
	sector_t lblock;
	int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
	int BlocksPerPage = 1 << l2BlocksPerPage;
	/* All callers are interested in block device's mapping */
	struct address_space *mapping =
		JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
	struct metapage *mp;
	struct page *page;
	unsigned int offset;

	/*
	 * Mark metapages to discard.  They will eventually be
	 * released, but should not be written.
	 */
	for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
	     lblock += BlocksPerPage) {
		page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
		if (!page)
			continue;
		for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
			mp = page_to_mp(page, offset);
			if (!mp)
				continue;
			if (mp->index < addr)
				continue;
			if (mp->index >= addr + len)
				break;

			clear_bit(META_dirty, &mp->flag);
			set_bit(META_discard, &mp->flag);
			if (mp->lsn)
				remove_from_logsync(mp);
		}
		unlock_page(page);
		page_cache_release(page);
	}
}

#ifdef CONFIG_JFS_STATISTICS
int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length,
		    int *eof, void *data)
{
	int len = 0;
	off_t begin;

	len += sprintf(buffer,
		       "JFS Metapage statistics\n"
		       "=======================\n"
		       "page allocations = %d\n"
		       "page frees = %d\n"
		       "lock waits = %d\n",
		       mpStat.pagealloc,
		       mpStat.pagefree,
		       mpStat.lockwait);

	begin = offset;
	*start = buffer + begin;
	len -= begin;

	if (len > length)
		len = length;
	else
		*eof = 1;

	if (len < 0)
		len = 0;

	return len;
}
#endif