[PATCH] ext3/EA: In-inode extended attributes for ext3

This started of as a patch by Alex Tomas <alex@clusterfs.com> and got an
overhaul by me.  The on-disk structure used is the same as in Alex's
original patch.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ext3/ialloc.c

@@ -596,6 +596,9 @@ struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
 	spin_unlock(&sbi->s_next_gen_lock);
 
 	ei->i_state = EXT3_STATE_NEW;
+	ei->i_extra_isize =
+		(EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) ?
+		sizeof(struct ext3_inode) - EXT3_GOOD_OLD_INODE_SIZE : 0;
 
 	ret = inode;
 	if(DQUOT_ALLOC_INODE(inode)) {

fs/ext3/inode.c

@@ -2385,7 +2385,9 @@ static int __ext3_get_inode_loc(struct inode *inode,
 
 int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
 {
-	return __ext3_get_inode_loc(inode, iloc, 1);
+	/* We have all inode data except xattrs in memory here. */
+	return __ext3_get_inode_loc(inode, iloc,
+		!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR));
 }
 
 void ext3_set_inode_flags(struct inode *inode)
@@ -2491,6 +2493,16 @@ void ext3_read_inode(struct inode * inode)
 		ei->i_data[block] = raw_inode->i_block[block];
 	INIT_LIST_HEAD(&ei->i_orphan);
 
+	ei->i_extra_isize =
+		(EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) ?
+		le16_to_cpu(raw_inode->i_extra_isize) : 0;
+	if (ei->i_extra_isize) {
+		__le32 *magic = (void *)raw_inode + EXT3_GOOD_OLD_INODE_SIZE +
+				ei->i_extra_isize;
+		if (le32_to_cpu(*magic))
+			 ei->i_state |= EXT3_STATE_XATTR;
+	}
+
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &ext3_file_inode_operations;
 		inode->i_fop = &ext3_file_operations;
@@ -2626,6 +2638,9 @@ static int ext3_do_update_inode(handle_t *handle,
 	} else for (block = 0; block < EXT3_N_BLOCKS; block++)
 		raw_inode->i_block[block] = ei->i_data[block];
 
+	if (EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE)
+		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
+
 	BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
 	rc = ext3_journal_dirty_metadata(handle, bh);
 	if (!err)

fs/ext3/xattr.h

@@ -31,6 +31,10 @@ struct ext3_xattr_header {
 	__u32	h_reserved[4];	/* zero right now */
 };
 
+struct ext3_xattr_ibody_header {
+	__le32	h_magic;	/* magic number for identification */
+};
+
 struct ext3_xattr_entry {
 	__u8	e_name_len;	/* length of name */
 	__u8	e_name_index;	/* attribute name index */

include/linux/ext3_fs.h

@@ -195,7 +195,7 @@ struct ext3_group_desc
  */
 #define EXT3_STATE_JDATA		0x00000001 /* journaled data exists */
 #define EXT3_STATE_NEW			0x00000002 /* inode is newly created */
-
+#define EXT3_STATE_XATTR		0x00000004 /* has in-inode xattrs */
 
 /* Used to pass group descriptor data when online resize is done */
 struct ext3_new_group_input {
@@ -293,6 +293,8 @@ struct ext3_inode {
 			__u32	m_i_reserved2[2];
 		} masix2;
 	} osd2;				/* OS dependent 2 */
+	__le16	i_extra_isize;
+	__le16	i_pad1;
 };
 
 #define i_size_high	i_dir_acl

include/linux/ext3_fs_i.h

@@ -113,6 +113,9 @@ struct ext3_inode_info {
 	 */
 	loff_t	i_disksize;
 
+	/* on-disk additional length */
+	__u16 i_extra_isize;
+
 	/*
 	 * truncate_sem is for serialising ext3_truncate() against
 	 * ext3_getblock().  In the 2.4 ext2 design, great chunks of inode's