f2fs: support F2FS_IOC_PRECACHE_EXTENTS

This patch introduces a new ioctl F2FS_IOC_PRECACHE_EXTENTS to precache
extent info like ext4, in order to gain better performance during
triggering AIO by eliminating synchronous waiting of mapping info.

Referred commit: 7869a4a6c5ca ("ext4: add support for extent pre-caching")

In addition, with newly added extent precache abilitiy, this patch add
to support FIEMAP_FLAG_CACHE in ->fiemap.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -865,6 +865,7 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
 		map.m_len = 0;
 
 	map.m_next_pgofs = NULL;
+	map.m_next_extent = NULL;
 	map.m_seg_type = NO_CHECK_TYPE;
 
 	if (direct_io) {
@@ -931,6 +932,7 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 	blkcnt_t prealloc;
 	struct extent_info ei = {0,0,0};
 	block_t blkaddr;
+	unsigned int start_pgofs;
 
 	if (!maxblocks)
 		return 0;
@@ -946,6 +948,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 		map->m_pblk = ei.blk + pgofs - ei.fofs;
 		map->m_len = min((pgoff_t)maxblocks, ei.fofs + ei.len - pgofs);
 		map->m_flags = F2FS_MAP_MAPPED;
+		if (map->m_next_extent)
+			*map->m_next_extent = pgofs + map->m_len;
 		goto out;
 	}
 
@@ -964,10 +968,14 @@ next_dnode:
 			if (map->m_next_pgofs)
 				*map->m_next_pgofs =
 					get_next_page_offset(&dn, pgofs);
+			if (map->m_next_extent)
+				*map->m_next_extent =
+					get_next_page_offset(&dn, pgofs);
 		}
 		goto unlock_out;
 	}
 
+	start_pgofs = pgofs;
 	prealloc = 0;
 	last_ofs_in_node = ofs_in_node = dn.ofs_in_node;
 	end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
@@ -1001,6 +1009,8 @@ next_block:
 				map->m_pblk = 0;
 				goto sync_out;
 			}
+			if (flag == F2FS_GET_BLOCK_PRECACHE)
+				goto sync_out;
 			if (flag == F2FS_GET_BLOCK_FIEMAP &&
 						blkaddr == NULL_ADDR) {
 				if (map->m_next_pgofs)
@@ -1059,6 +1069,16 @@ skip:
 	else if (dn.ofs_in_node < end_offset)
 		goto next_block;
 
+	if (flag == F2FS_GET_BLOCK_PRECACHE) {
+		if (map->m_flags & F2FS_MAP_MAPPED) {
+			unsigned int ofs = start_pgofs - map->m_lblk;
+
+			f2fs_update_extent_cache_range(&dn,
+				start_pgofs, map->m_pblk + ofs,
+				map->m_len - ofs);
+		}
+	}
+
 	f2fs_put_dnode(&dn);
 
 	if (create) {
@@ -1068,6 +1088,17 @@ skip:
 	goto next_dnode;
 
 sync_out:
+	if (flag == F2FS_GET_BLOCK_PRECACHE) {
+		if (map->m_flags & F2FS_MAP_MAPPED) {
+			unsigned int ofs = start_pgofs - map->m_lblk;
+
+			f2fs_update_extent_cache_range(&dn,
+				start_pgofs, map->m_pblk + ofs,
+				map->m_len - ofs);
+		}
+		if (map->m_next_extent)
+			*map->m_next_extent = pgofs + 1;
+	}
 	f2fs_put_dnode(&dn);
 unlock_out:
 	if (create) {
@@ -1089,6 +1120,7 @@ static int __get_data_block(struct inode *inode, sector_t iblock,
 	map.m_lblk = iblock;
 	map.m_len = bh->b_size >> inode->i_blkbits;
 	map.m_next_pgofs = next_pgofs;
+	map.m_next_extent = NULL;
 	map.m_seg_type = seg_type;
 
 	err = f2fs_map_blocks(inode, &map, create, flag);
@@ -1212,6 +1244,12 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 	u32 flags = 0;
 	int ret = 0;
 
+	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
+		ret = f2fs_precache_extents(inode);
+		if (ret)
+			return ret;
+	}
+
 	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR);
 	if (ret)
 		return ret;
@@ -1313,6 +1351,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 	map.m_len = 0;
 	map.m_flags = 0;
 	map.m_next_pgofs = NULL;
+	map.m_next_extent = NULL;
 	map.m_seg_type = NO_CHECK_TYPE;
 
 	for (; nr_pages; nr_pages--) {

fs/f2fs/f2fs.h

@@ -358,6 +358,7 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
 #define F2FS_IOC_GET_FEATURES		_IOR(F2FS_IOCTL_MAGIC, 12, __u32)
 #define F2FS_IOC_SET_PIN_FILE		_IOW(F2FS_IOCTL_MAGIC, 13, __u32)
 #define F2FS_IOC_GET_PIN_FILE		_IOR(F2FS_IOCTL_MAGIC, 14, __u32)
+#define F2FS_IOC_PRECACHE_EXTENTS	_IO(F2FS_IOCTL_MAGIC, 15)
 
 #define F2FS_IOC_SET_ENCRYPTION_POLICY	FS_IOC_SET_ENCRYPTION_POLICY
 #define F2FS_IOC_GET_ENCRYPTION_POLICY	FS_IOC_GET_ENCRYPTION_POLICY
@@ -553,6 +554,7 @@ struct f2fs_map_blocks {
 	unsigned int m_len;
 	unsigned int m_flags;
 	pgoff_t *m_next_pgofs;		/* point next possible non-hole pgofs */
+	pgoff_t *m_next_extent;		/* point to next possible extent */
 	int m_seg_type;
 };
 
@@ -563,6 +565,7 @@ enum {
 	F2FS_GET_BLOCK_BMAP,
 	F2FS_GET_BLOCK_PRE_DIO,
 	F2FS_GET_BLOCK_PRE_AIO,
+	F2FS_GET_BLOCK_PRECACHE,
 };
 
 /*
@@ -2564,6 +2567,7 @@ int f2fs_getattr(const struct path *path, struct kstat *stat,
 int f2fs_setattr(struct dentry *dentry, struct iattr *attr);
 int truncate_hole(struct inode *inode, pgoff_t pg_start, pgoff_t pg_end);
 void truncate_data_blocks_range(struct dnode_of_data *dn, int count);
+int f2fs_precache_extents(struct inode *inode);
 long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
 long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 int f2fs_pin_file_control(struct inode *inode, bool inc);

fs/f2fs/file.c

@@ -1423,7 +1423,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct f2fs_map_blocks map = { .m_next_pgofs = NULL,
-					.m_seg_type = NO_CHECK_TYPE };
+			.m_next_extent = NULL, .m_seg_type = NO_CHECK_TYPE };
 	pgoff_t pg_end;
 	loff_t new_size = i_size_read(inode);
 	loff_t off_end;
@@ -2072,7 +2072,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 {
 	struct inode *inode = file_inode(filp);
 	struct f2fs_map_blocks map = { .m_next_pgofs = NULL,
-					.m_seg_type = NO_CHECK_TYPE };
+			.m_next_extent = NULL, .m_seg_type = NO_CHECK_TYPE };
 	struct extent_info ei = {0,0,0};
 	pgoff_t pg_start, pg_end;
 	unsigned int blk_per_seg = sbi->blocks_per_seg;
@@ -2749,6 +2749,43 @@ static int f2fs_ioc_get_pin_file(struct file *filp, unsigned long arg)
 	return put_user(pin, (u32 __user *)arg);
 }
 
+int f2fs_precache_extents(struct inode *inode)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_map_blocks map;
+	pgoff_t m_next_extent;
+	loff_t end;
+	int err;
+
+	if (is_inode_flag_set(inode, FI_NO_EXTENT))
+		return -EOPNOTSUPP;
+
+	map.m_lblk = 0;
+	map.m_next_pgofs = NULL;
+	map.m_next_extent = &m_next_extent;
+	map.m_seg_type = NO_CHECK_TYPE;
+	end = F2FS_I_SB(inode)->max_file_blocks;
+
+	while (map.m_lblk < end) {
+		map.m_len = end - map.m_lblk;
+
+		down_write(&fi->dio_rwsem[WRITE]);
+		err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_PRECACHE);
+		up_write(&fi->dio_rwsem[WRITE]);
+		if (err)
+			return err;
+
+		map.m_lblk = m_next_extent;
+	}
+
+	return err;
+}
+
+static int f2fs_ioc_precache_extents(struct file *filp, unsigned long arg)
+{
+	return f2fs_precache_extents(file_inode(filp));
+}
+
 long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
@@ -2803,6 +2840,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_ioc_get_pin_file(filp, arg);
 	case F2FS_IOC_SET_PIN_FILE:
 		return f2fs_ioc_set_pin_file(filp, arg);
+	case F2FS_IOC_PRECACHE_EXTENTS:
+		return f2fs_ioc_precache_extents(filp, arg);
 	default:
 		return -ENOTTY;
 	}
@@ -2880,6 +2919,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case F2FS_IOC_FSSETXATTR:
 	case F2FS_IOC_GET_PIN_FILE:
 	case F2FS_IOC_SET_PIN_FILE:
+	case F2FS_IOC_PRECACHE_EXTENTS:
 		break;
 	default:
 		return -ENOIOCTLCMD;