ext4: add the basic function for inline data support

Implement inline data with xattr.

Now we use "system.data" to store xattr, and the xattr will
be extended if the i_size is increased while we don't release
the space during truncate.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/Makefile

@@ -9,6 +9,6 @@ ext4-y	:= balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
 		ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o \
 		mmp.o indirect.o extents_status.o
 
-ext4-$(CONFIG_EXT4_FS_XATTR)		+= xattr.o xattr_user.o xattr_trusted.o
+ext4-$(CONFIG_EXT4_FS_XATTR)		+= xattr.o xattr_user.o xattr_trusted.o inline.o
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
 ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o

fs/ext4/ext4.h

@@ -402,6 +402,7 @@ struct flex_groups {
 #define EXT4_EXTENTS_FL			0x00080000 /* Inode uses extents */
 #define EXT4_EA_INODE_FL	        0x00200000 /* Inode used for large EA */
 #define EXT4_EOFBLOCKS_FL		0x00400000 /* Blocks allocated beyond EOF */
+#define EXT4_INLINE_DATA_FL		0x10000000 /* Inode has inline data. */
 #define EXT4_RESERVED_FL		0x80000000 /* reserved for ext4 lib */
 
 #define EXT4_FL_USER_VISIBLE		0x004BDFFF /* User visible flags */
@@ -458,6 +459,7 @@ enum {
 	EXT4_INODE_EXTENTS	= 19,	/* Inode uses extents */
 	EXT4_INODE_EA_INODE	= 21,	/* Inode used for large EA */
 	EXT4_INODE_EOFBLOCKS	= 22,	/* Blocks allocated beyond EOF */
+	EXT4_INODE_INLINE_DATA	= 28,	/* Data in inode. */
 	EXT4_INODE_RESERVED	= 31,	/* reserved for ext4 lib */
 };
 
@@ -504,6 +506,7 @@ static inline void ext4_check_flag_values(void)
 	CHECK_FLAG_VALUE(EXTENTS);
 	CHECK_FLAG_VALUE(EA_INODE);
 	CHECK_FLAG_VALUE(EOFBLOCKS);
+	CHECK_FLAG_VALUE(INLINE_DATA);
 	CHECK_FLAG_VALUE(RESERVED);
 }
 
@@ -918,6 +921,10 @@ struct ext4_inode_info {
 	/* on-disk additional length */
 	__u16 i_extra_isize;
 
+	/* Indicate the inline data space. */
+	u16 i_inline_off;
+	u16 i_inline_size;
+
 #ifdef CONFIG_QUOTA
 	/* quota space reservation, managed internally by quota code */
 	qsize_t i_reserved_quota;
@@ -1376,6 +1383,7 @@ enum {
 	EXT4_STATE_DELALLOC_RESERVED,	/* blks already reserved for delalloc */
 	EXT4_STATE_DIOREAD_LOCK,	/* Disable support for dio read
 					   nolocking */
+	EXT4_STATE_MAY_INLINE_DATA,	/* may have in-inode data */
 };
 
 #define EXT4_INODE_BIT_FNS(name, field, offset)				\
@@ -1497,7 +1505,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
 #define EXT4_FEATURE_INCOMPAT_DIRDATA		0x1000 /* data in dirent */
 #define EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM	0x2000 /* use crc32c for bg */
 #define EXT4_FEATURE_INCOMPAT_LARGEDIR		0x4000 /* >2GB or 3-lvl htree */
-#define EXT4_FEATURE_INCOMPAT_INLINEDATA	0x8000 /* data in inode */
+#define EXT4_FEATURE_INCOMPAT_INLINE_DATA	0x8000 /* data in inode */
 
 #define EXT2_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \

fs/ext4/inode.c

@@ -3706,8 +3706,10 @@ static inline void ext4_iget_extra_inode(struct inode *inode,
 {
 	__le32 *magic = (void *)raw_inode +
 			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
-	if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+	if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
+		ext4_find_inline_data_nolock(inode);
+	}
 }
 
 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
@@ -3780,6 +3782,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
 
 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
+	ei->i_inline_off = 0;
 	ei->i_dir_start_lookup = 0;
 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
 	/* We now have enough fields to check if the inode was active or not.

fs/ext4/xattr.h

@@ -21,6 +21,7 @@
 #define EXT4_XATTR_INDEX_TRUSTED		4
 #define	EXT4_XATTR_INDEX_LUSTRE			5
 #define EXT4_XATTR_INDEX_SECURITY	        6
+#define EXT4_XATTR_INDEX_SYSTEM			7
 
 struct ext4_xattr_header {
 	__le32	h_magic;	/* magic number for identification */
@@ -125,6 +126,19 @@ extern int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 				struct ext4_xattr_info *i,
 				struct ext4_xattr_ibody_find *is);
 
+extern int ext4_has_inline_data(struct inode *inode);
+extern int ext4_get_inline_size(struct inode *inode);
+extern int ext4_get_max_inline_size(struct inode *inode);
+extern int ext4_find_inline_data_nolock(struct inode *inode);
+extern void ext4_write_inline_data(struct inode *inode,
+				   struct ext4_iloc *iloc,
+				   void *buffer, loff_t pos,
+				   unsigned int len);
+extern int ext4_prepare_inline_data(handle_t *handle, struct inode *inode,
+				    unsigned int len);
+extern int ext4_init_inline_data(handle_t *handle, struct inode *inode,
+				 unsigned int len);
+extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
 # else  /* CONFIG_EXT4_FS_XATTR */
 
 static inline int
@@ -201,6 +215,46 @@ ext4_xattr_ibody_get(struct inode *inode, int name_index,
 	return -EOPNOTSUPP;
 }
 
+static inline int ext4_find_inline_data_nolock(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int ext4_has_inline_data(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int ext4_get_inline_size(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int ext4_get_max_inline_size(struct inode *inode)
+{
+	return 0;
+}
+
+static inline void ext4_write_inline_data(struct inode *inode,
+					  struct ext4_iloc *iloc,
+					  void *buffer, loff_t pos,
+					  unsigned int len)
+{
+	return;
+}
+
+static inline int ext4_init_inline_data(handle_t *handle,
+					struct inode *inode,
+					unsigned int len)
+{
+	return 0;
+}
+
+static inline int ext4_destroy_inline_data(handle_t *handle,
+					   struct inode *inode)
+{
+	return 0;
+}
 # endif  /* CONFIG_EXT4_FS_XATTR */
 
 #ifdef CONFIG_EXT4_FS_SECURITY