f2fs: enhance on-disk inode structure scalability

This patch add new flag F2FS_EXTRA_ATTR storing in inode.i_inline
to indicate that on-disk structure of current inode is extended.

In order to extend, we changed the inode structure a bit:

Original one:

struct f2fs_inode {
	...
	struct f2fs_extent i_ext;
	__le32 i_addr[DEF_ADDRS_PER_INODE];
	__le32 i_nid[DEF_NIDS_PER_INODE];
}

Extended one:

struct f2fs_inode {
        ...
        struct f2fs_extent i_ext;
	union {
		struct {
			__le16 i_extra_isize;
			__le16 i_padding;
			__le32 i_extra_end[0];
		};
		__le32 i_addr[DEF_ADDRS_PER_INODE];
	};
        __le32 i_nid[DEF_NIDS_PER_INODE];
}

Once F2FS_EXTRA_ATTR is set, we will steal four bytes in the head of
i_addr field for storing i_extra_isize and i_padding. with i_extra_isize,
we can calculate actual size of reserved space in i_addr, available
attribute fields included in total extra attribute fields for current
inode can be described as below:

  +--------------------+
  | .i_mode            |
  | ...                |
  | .i_ext             |
  +--------------------+
  | .i_extra_isize     |-----+
  | .i_padding         |     |
  | .i_prjid           |     |
  | .i_atime_extra     |     |
  | .i_ctime_extra     |     |
  | .i_mtime_extra     |<----+
  | .i_inode_cs        |<----- store blkaddr/inline from here
  | .i_xattr_cs        |
  | ...                |
  +--------------------+
  |                    |
  |    block address   |
  |                    |
  +--------------------+
  | .i_nid             |
  +--------------------+
  |   node_footer      |
  | (nid, ino, offset) |
  +--------------------+

Hence, with this patch, we would enhance scalability of f2fs inode for
storing more newly added attribute.

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

1 files changed, 21 insertions, 11 deletions

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 32ec6b23fe01..0a6699a23dfb 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -49,20 +49,22 @@ void f2fs_set_inode_flags(struct inode *inode)
 
 static void __get_inode_rdev(struct inode *inode, struct f2fs_inode *ri)
 {
+	int extra_size = get_extra_isize(inode);
+
 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
-		if (ri->i_addr[0])
-			inode->i_rdev =
-				old_decode_dev(le32_to_cpu(ri->i_addr[0]));
+		if (ri->i_addr[extra_size])
+			inode->i_rdev = old_decode_dev(
+				le32_to_cpu(ri->i_addr[extra_size]));
 		else
-			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(ri->i_addr[1]));
+			inode->i_rdev = new_decode_dev(
+				le32_to_cpu(ri->i_addr[extra_size + 1]));
 	}
 }
 
 static bool __written_first_block(struct f2fs_inode *ri)
 {
-	block_t addr = le32_to_cpu(ri->i_addr[0]);
+	block_t addr = le32_to_cpu(ri->i_addr[offset_in_addr(ri)]);
 
 	if (addr != NEW_ADDR && addr != NULL_ADDR)
 		return true;
@@ -71,16 +73,18 @@ static bool __written_first_block(struct f2fs_inode *ri)
 
 static void __set_inode_rdev(struct inode *inode, struct f2fs_inode *ri)
 {
+	int extra_size = get_extra_isize(inode);
+
 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
 		if (old_valid_dev(inode->i_rdev)) {
-			ri->i_addr[0] =
+			ri->i_addr[extra_size] =
 				cpu_to_le32(old_encode_dev(inode->i_rdev));
-			ri->i_addr[1] = 0;
+			ri->i_addr[extra_size + 1] = 0;
 		} else {
-			ri->i_addr[0] = 0;
-			ri->i_addr[1] =
+			ri->i_addr[extra_size] = 0;
+			ri->i_addr[extra_size + 1] =
 				cpu_to_le32(new_encode_dev(inode->i_rdev));
-			ri->i_addr[2] = 0;
+			ri->i_addr[extra_size + 2] = 0;
 		}
 	}
 }
@@ -153,6 +157,9 @@ static int do_read_inode(struct inode *inode)
 
 	get_inline_info(inode, ri);
 
+	fi->i_extra_isize = f2fs_has_extra_attr(inode) ?
+					le16_to_cpu(ri->i_extra_isize) : 0;
+
 	/* check data exist */
 	if (f2fs_has_inline_data(inode) && !f2fs_exist_data(inode))
 		__recover_inline_status(inode, node_page);
@@ -292,6 +299,9 @@ int update_inode(struct inode *inode, struct page *node_page)
 	ri->i_generation = cpu_to_le32(inode->i_generation);
 	ri->i_dir_level = F2FS_I(inode)->i_dir_level;
 
+	if (f2fs_has_extra_attr(inode))
+		ri->i_extra_isize = cpu_to_le16(F2FS_I(inode)->i_extra_isize);
+
 	__set_inode_rdev(inode, ri);
 	set_cold_node(inode, node_page);