[PATCH] ext4: 48bit i_file_acl

As we are planning to support 48-bit block numbers for ext4, we need to
support 48-bit block numbers for extended attributes.  In the short term, we
can do this by reuse (on-disk) 16-bit padding (linux2.i_pad1 currently used
only by "hurd") as high order bits for xattr.  This patch basically does that.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ext4/inode.c

@@ -2643,6 +2643,11 @@ void ext4_read_inode(struct inode * inode)
 	ei->i_frag_size = raw_inode->i_fsize;
 #endif
 	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
+	if ((sizeof(sector_t) > 4) &&
+	    (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+	     cpu_to_le32(EXT4_OS_HURD)))
+		ei->i_file_acl |=
+			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
 	if (!S_ISREG(inode->i_mode)) {
 		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
 	} else {
@@ -2776,6 +2781,11 @@ static int ext4_do_update_inode(handle_t *handle,
 	raw_inode->i_frag = ei->i_frag_no;
 	raw_inode->i_fsize = ei->i_frag_size;
 #endif
+	if ((sizeof(sector_t) > 4) &&
+	    (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+	     cpu_to_le32(EXT4_OS_HURD)))
+		raw_inode->i_file_acl_high =
+			cpu_to_le16(ei->i_file_acl >> 32);
 	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
 	if (!S_ISREG(inode->i_mode)) {
 		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);

include/linux/ext4_fs.h

@@ -298,7 +298,7 @@ struct ext4_inode {
 		struct {
 			__u8	l_i_frag;	/* Fragment number */
 			__u8	l_i_fsize;	/* Fragment size */
-			__u16	i_pad1;
+			__le16	l_i_file_acl_high;
 			__le16	l_i_uid_high;	/* these 2 fields    */
 			__le16	l_i_gid_high;	/* were reserved2[0] */
 			__u32	l_i_reserved2;
@@ -314,7 +314,7 @@ struct ext4_inode {
 		struct {
 			__u8	m_i_frag;	/* Fragment number */
 			__u8	m_i_fsize;	/* Fragment size */
-			__u16	m_pad1;
+			__le16	m_i_file_acl_high;
 			__u32	m_i_reserved2[2];
 		} masix2;
 	} osd2;				/* OS dependent 2 */
@@ -328,6 +328,7 @@ struct ext4_inode {
 #define i_reserved1	osd1.linux1.l_i_reserved1
 #define i_frag		osd2.linux2.l_i_frag
 #define i_fsize		osd2.linux2.l_i_fsize
+#define i_file_acl_high	osd2.linux2.l_i_file_acl_high
 #define i_uid_low	i_uid
 #define i_gid_low	i_gid
 #define i_uid_high	osd2.linux2.l_i_uid_high
@@ -348,6 +349,7 @@ struct ext4_inode {
 #define i_reserved1	osd1.masix1.m_i_reserved1
 #define i_frag		osd2.masix2.m_i_frag
 #define i_fsize		osd2.masix2.m_i_fsize
+#define i_file_acl_high	osd2.masix2.m_i_file_acl_high
 #define i_reserved2	osd2.masix2.m_i_reserved2
 
 #endif /* defined(__KERNEL__) || defined(__linux__) */