Commit b4d07a3e authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: avoid f2fs_lock_op in f2fs_write_begin 



If f2fs_write_begin is to update data, we can bypass calling f2fs_lock_op() in
order to avoid the checkpoint latency in the write syscall.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 4aa69d56

fs/f2fs/data.c

+34 −8
Original line number Diff line number Diff line
@@ -1418,10 +1418,16 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi, 
	pgoff_t index = page->index;

	struct dnode_of_data dn;

	struct page *ipage;

	bool locked = false;

	struct extent_info ei;

	int err = 0;



	if (f2fs_has_inline_data(inode) ||

			(pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {

		f2fs_lock_op(sbi);



		locked = true;

	}

restart:

	/* check inline_data */

	ipage = get_node_page(sbi, inode->i_ino);

	if (IS_ERR(ipage)) {
@@ -1436,21 +1442,41 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi, 
			read_inline_data(page, ipage);

			set_inode_flag(F2FS_I(inode), FI_DATA_EXIST);

			sync_inode_page(&dn);

			goto done;

		} else {

			err = f2fs_convert_inline_page(&dn, page);

			if (err)

				goto err_out;

		}

				goto out;

			if (dn.data_blkaddr == NULL_ADDR)

				err = f2fs_get_block(&dn, index);

		}

	} else if (locked) {

		err = f2fs_get_block(&dn, index);

done:

	} else {

		if (f2fs_lookup_extent_cache(inode, index, &ei)) {

			dn.data_blkaddr = ei.blk + index - ei.fofs;

		} else {

			bool restart = false;



			/* hole case */

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

			if (err || (!err && dn.data_blkaddr == NULL_ADDR))

				restart = true;

			if (restart) {

				f2fs_put_dnode(&dn);

				f2fs_lock_op(sbi);

				locked = true;

				goto restart;

			}

		}

	}



	/* convert_inline_page can make node_changed */

	*blk_addr = dn.data_blkaddr;

	*node_changed = dn.node_changed;

err_out:

out:

	f2fs_put_dnode(&dn);

unlock_out:

	if (locked)

		f2fs_unlock_op(sbi);

	return err;

}