Commit 266e97a8 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: introduce readahead mode of node pages 



Previously, f2fs reads several node pages ahead when get_dnode_of_data is called
with RDONLY_NODE flag.
And, this flag is set by the following functions.
- get_data_block_ro
- get_lock_data_page
- do_write_data_page
- truncate_blocks
- truncate_hole

However, this readahead mechanism is initially introduced for the use of
get_data_block_ro to enhance the sequential read performance.

So, let's clarify all the cases with the additional modes as follows.

enum {
	ALLOC_NODE,	/* allocate a new node page if needed */
	LOOKUP_NODE,	/* look up a node without readahead */
	LOOKUP_NODE_RA,	/*
			 * look up a node with readahead called
			 * by get_datablock_ro.
			 */
}

Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
Reviewed-by: default avatarNamjae Jeon <namjae.jeon@samsung.com>
parent 66d36a29

fs/f2fs/data.c

+6 −6
Original line number Diff line number Diff line
@@ -183,7 +183,7 @@ struct page *find_data_page(struct inode *inode, pgoff_t index) 
	f2fs_put_page(page, 0);



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, index, RDONLY_NODE);

	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);

	if (err)

		return ERR_PTR(err);

	f2fs_put_dnode(&dn);
@@ -222,7 +222,7 @@ struct page *get_lock_data_page(struct inode *inode, pgoff_t index) 
	int err;



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, index, RDONLY_NODE);

	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);

	if (err)

		return ERR_PTR(err);

	f2fs_put_dnode(&dn);
@@ -262,7 +262,7 @@ struct page *get_new_data_page(struct inode *inode, pgoff_t index, 
	int err;



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, index, 0);

	err = get_dnode_of_data(&dn, index, ALLOC_NODE);

	if (err)

		return ERR_PTR(err);
@@ -392,7 +392,7 @@ static int get_data_block_ro(struct inode *inode, sector_t iblock, 


	/* When reading holes, we need its node page */

	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, pgofs, RDONLY_NODE);

	err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);

	if (err)

		return (err == -ENOENT) ? 0 : err;
@@ -443,7 +443,7 @@ int do_write_data_page(struct page *page) 
	int err = 0;



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, page->index, RDONLY_NODE);

	err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);

	if (err)

		return err;
@@ -607,7 +607,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, 
	mutex_lock_op(sbi, DATA_NEW);



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, index, 0);

	err = get_dnode_of_data(&dn, index, ALLOC_NODE);

	if (err) {

		mutex_unlock_op(sbi, DATA_NEW);

		f2fs_put_page(page, 1);

fs/f2fs/f2fs.h

+8 −4
Original line number Diff line number Diff line
@@ -125,11 +125,15 @@ static inline int update_sits_in_cursum(struct f2fs_summary_block *rs, int i) 
					 * file keeping -1 as its node offset to

					 * distinguish from index node blocks.

					 */

#define RDONLY_NODE		1	/*

					 * specify a read-only mode when getting

					 * a node block. 0 is read-write mode.

					 * used by get_dnode_of_data().

enum {

	ALLOC_NODE,			/* allocate a new node page if needed */

	LOOKUP_NODE,			/* look up a node without readahead */

	LOOKUP_NODE_RA,			/*

					 * look up a node with readahead called

					 * by get_datablock_ro.

					 */

};



#define F2FS_LINK_MAX		32000	/* maximum link count per file */



/* for in-memory extent cache entry */

fs/f2fs/file.c

+4 −4
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ static int f2fs_vm_page_mkwrite(struct vm_area_struct *vma, 


	/* block allocation */

	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, page->index, 0);

	err = get_dnode_of_data(&dn, page->index, ALLOC_NODE);

	if (err) {

		mutex_unlock_op(sbi, DATA_NEW);

		goto out;
@@ -258,7 +258,7 @@ static int truncate_blocks(struct inode *inode, u64 from) 
	mutex_lock_op(sbi, DATA_TRUNC);



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	err = get_dnode_of_data(&dn, free_from, RDONLY_NODE);

	err = get_dnode_of_data(&dn, free_from, LOOKUP_NODE);

	if (err) {

		if (err == -ENOENT)

			goto free_next;
@@ -420,7 +420,7 @@ int truncate_hole(struct inode *inode, pgoff_t pg_start, pgoff_t pg_end) 


		mutex_lock_op(sbi, DATA_TRUNC);

		set_new_dnode(&dn, inode, NULL, NULL, 0);

		err = get_dnode_of_data(&dn, index, RDONLY_NODE);

		err = get_dnode_of_data(&dn, index, LOOKUP_NODE);

		if (err) {

			mutex_unlock_op(sbi, DATA_TRUNC);

			if (err == -ENOENT)
@@ -504,7 +504,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset, 
		mutex_lock_op(sbi, DATA_NEW);



		set_new_dnode(&dn, inode, NULL, NULL, 0);

		ret = get_dnode_of_data(&dn, index, 0);

		ret = get_dnode_of_data(&dn, index, ALLOC_NODE);

		if (ret) {

			mutex_unlock_op(sbi, DATA_NEW);

			break;

fs/f2fs/node.c

+3 −3
Original line number Diff line number Diff line
@@ -384,7 +384,7 @@ static int get_node_path(long block, int offset[4], unsigned int noffset[4]) 
/*

 * Caller should call f2fs_put_dnode(dn).

 */

int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int ro)

int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)

{

	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);

	struct page *npage[4];
@@ -411,7 +411,7 @@ int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int ro) 
	for (i = 1; i <= level; i++) {

		bool done = false;



		if (!nids[i] && !ro) {

		if (!nids[i] && mode == ALLOC_NODE) {

			mutex_lock_op(sbi, NODE_NEW);



			/* alloc new node */
@@ -434,7 +434,7 @@ int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int ro) 
			alloc_nid_done(sbi, nids[i]);

			mutex_unlock_op(sbi, NODE_NEW);

			done = true;

		} else if (ro && i == level && level > 1) {

		} else if (mode == LOOKUP_NODE_RA && i == level && level > 1) {

			npage[i] = get_node_page_ra(parent, offset[i - 1]);

			if (IS_ERR(npage[i])) {

				err = PTR_ERR(npage[i]);

fs/f2fs/recovery.c

+1 −1
Original line number Diff line number Diff line
@@ -247,7 +247,7 @@ static void do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode, 
		end = start + ADDRS_PER_BLOCK;



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	if (get_dnode_of_data(&dn, start, 0))

	if (get_dnode_of_data(&dn, start, ALLOC_NODE))

		return;



	wait_on_page_writeback(dn.node_page);