ext4: adds project ID support

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 06c3afc..2047ff7 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3208,6 +3208,12 @@
 	if (ext4_encrypted_inode(dir) &&
 	    !ext4_is_child_context_consistent_with_parent(dir, inode))
 		return -EPERM;
+
+       if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
+	   (!projid_eq(EXT4_I(dir)->i_projid,
+		       EXT4_I(old_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
 	err = dquot_initialize(dir);
 	if (err)
 		return err;
@@ -3488,6 +3494,11 @@
 	int credits;
 	u8 old_file_type;
 
+	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
+	    (!projid_eq(EXT4_I(new_dir)->i_projid,
+			EXT4_I(old_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
 	retval = dquot_initialize(old.dir);
 	if (retval)
 		return retval;
@@ -3697,6 +3708,14 @@
 							   new.inode)))
 		return -EPERM;
 
+	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
+	     !projid_eq(EXT4_I(new_dir)->i_projid,
+			EXT4_I(old_dentry->d_inode)->i_projid)) ||
+	    (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
+	     !projid_eq(EXT4_I(old_dir)->i_projid,
+			EXT4_I(new_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
 	retval = dquot_initialize(old.dir);
 	if (retval)
 		return retval;