Commit 98dc568b authored Aug 10, 2010 by Miklos Szeredi Committed by Al Viro Aug 11, 2010

vfs: __d_path: dont prepend the name of the root dentry



In the old times pseudo-filesystems set the name of theroot dentry to
some prefix like "pipe:" and the name of the child dentry to "[123]"
and relied on a hack in __d_path() to replace the preceding slash with
the root's name to get "pipe:[123]".

Then the d_dname() dentry operation was introduced which solved the
same problem without having to pre-fill the name in each dentry.

Currently the following pseudo filesystems exist in the kernel:

perfmon
mtd
anon_inode
bdev
pipe
socket

Of these only perfmon, anon_inode, pipe and socket create
sub-dentries, all of which have now been switched to using d_dname().

bdev and mtd only create inodes.

This means that now the hack to overwrite the slash can be removed, so
for unreachable paths (e.g. within a detached mount) the path string
won't be polluted with garbage.  For these cases a subsequent patch
will add a prefix, indicating that the path is unreachable.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 7ae6bdbd

fs/dcache.c

+9 −3

Original line number	Original line	Diff line number	Diff line
	@@ -1970,9 +1970,15 @@ out:
	return retval;		return retval;

	global_root:		global_root:
	retval += 1; /* hit the slash */		/*
	if (prepend_name(&retval, &buflen, &dentry->d_name) != 0)		* Filesystems needing to implement special "root names"
	goto Elong;		* should do so with ->d_dname()
			*/
			if (IS_ROOT(dentry) &&
			(dentry->d_name.len != 1 \|\| dentry->d_name.name[0] != '/')) {
			WARN(1, "Root dentry has weird name <%.*s>\n",
			(int) dentry->d_name.len, dentry->d_name.name);
			}
	root->mnt = vfsmnt;		root->mnt = vfsmnt;
	root->dentry = dentry;		root->dentry = dentry;
	goto out;		goto out;

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