i_op->listxattr semantics

i_op->listxattr semantics

[Will Dyson]

Hello all,

I am attempting to implement support for extended attributes in the Be
Filesystem (befs) driver. But I am stuck trying to figure out why the
getfattr program does not list my attributes.

Below is a test version of befs_listxattr that gives all files one
attribute named "MyAttr". When I mount my filesystem on /befs (in
2.5.69-uml) and issue the command "getfattr -d /befs", no attributes are
printed. The debugging statements appear in my syslog, so I know the
function is being called.

Can anyone help me figure out what I am doing wrong? Thanks!

static ssize_t
befs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	struct super_block *sb = dentry->d_inode->i_sb;
	ssize_t attr_len = 0;
	char *attr = "MyAttr";

	befs_debug(sb, "---> befs_listxattr for inode %lu "
			"with %d buffer_size",
			dentry->d_inode->i_ino, size);

	attr_len = strlen(attr);
	
	if (buffer) {
		memcpy(buffer, attr, attr_len);
		buffer[attr_len] = '\0';
	}
	
	befs_debug(sb, "<--- befs_listxattr");
	return attr_len + 1;
}



-- 
Will Dyson
"Back off man, I'm a scientist!" -Dr. Peter Venkman

Re: i_op->listxattr semantics

[Nathan Scott]

On Sat, Jun 07, 2003 at 09:34:34PM -0400, Will Dyson wrote:
> Hello all,
> 
> I am attempting to implement support for extended attributes in the Be
> Filesystem (befs) driver. But I am stuck trying to figure out why the
> getfattr program does not list my attributes.
> 
> Below is a test version of befs_listxattr that gives all files one
> attribute named "MyAttr". When I mount my filesystem on /befs (in
> 2.5.69-uml) and issue the command "getfattr -d /befs", no attributes are
> printed. The debugging statements appear in my syslog, so I know the
> function is being called.
> 
> Can anyone help me figure out what I am doing wrong? Thanks!

At first guess, probably the lack of a namespace prefix is causing
your problem - see attr(5) and listxattr(2).

> static ssize_t
> befs_listxattr(struct dentry *dentry, char *buffer, size_t size)
> {
> 	struct super_block *sb = dentry->d_inode->i_sb;
> 	ssize_t attr_len = 0;
> 	char *attr = "MyAttr";

Try 's/MyAttr/user.MyAttr/g' or whichever namespace is appropriate.

cheers.

-- 
Nathan