xfs: create a separate hashname function for extended attributes

Create a separate function to compute name hashvalues for extended
attributes.  When we get to parent pointers we'll be altering the rules
so that metadump obfuscation doesn't turn heinous.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

3 files changed, 41 insertions, 4 deletions

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 50eab63ff3be..8262c263be9d 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -280,7 +280,7 @@ xfs_attr_get(
 		args->owner = args->dp->i_ino;
 	args->geo = args->dp->i_mount->m_attr_geo;
 	args->whichfork = XFS_ATTR_FORK;
-	args->hashval = xfs_da_hashname(args->name, args->namelen);
+	xfs_attr_sethash(args);
 
 	/* Entirely possible to look up a name which doesn't exist */
 	args->op_flags = XFS_DA_OP_OKNOENT;
@@ -415,6 +415,30 @@ out:
 	return error;
 }
 
+/* Compute the hash value for a user/root/secure extended attribute */
+xfs_dahash_t
+xfs_attr_hashname(
+	const uint8_t		*name,
+	int			namelen)
+{
+	return xfs_da_hashname(name, namelen);
+}
+
+/* Compute the hash value for any extended attribute from any namespace. */
+xfs_dahash_t
+xfs_attr_hashval(
+	struct xfs_mount	*mp,
+	unsigned int		attr_flags,
+	const uint8_t		*name,
+	int			namelen,
+	const void		*value,
+	int			valuelen)
+{
+	ASSERT(xfs_attr_check_namespace(attr_flags));
+
+	return xfs_attr_hashname(name, namelen);
+}
+
 /*
  * Handle the state change on completion of a multi-state attr operation.
  *
@@ -925,7 +949,7 @@ xfs_attr_set(
 		args->owner = args->dp->i_ino;
 	args->geo = mp->m_attr_geo;
 	args->whichfork = XFS_ATTR_FORK;
-	args->hashval = xfs_da_hashname(args->name, args->namelen);
+	xfs_attr_sethash(args);
 
 	/*
 	 * We have no control over the attribute names that userspace passes us
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index cd106b0a424f..c63b1d610e53 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -628,6 +628,20 @@ xfs_attr_init_replace_state(struct xfs_da_args *args)
 	return xfs_attr_init_add_state(args);
 }
 
+xfs_dahash_t xfs_attr_hashname(const uint8_t *name, int namelen);
+
+xfs_dahash_t xfs_attr_hashval(struct xfs_mount *mp, unsigned int attr_flags,
+		const uint8_t *name, int namelen, const void *value,
+		int valuelen);
+
+/* Set the hash value for any extended attribute from any namespace. */
+static inline void xfs_attr_sethash(struct xfs_da_args *args)
+{
+	args->hashval = xfs_attr_hashval(args->dp->i_mount, args->attr_filter,
+					 args->name, args->namelen,
+					 args->value, args->valuelen);
+}
+
 extern struct kmem_cache *xfs_attr_intent_cache;
 int __init xfs_attr_intent_init_cache(void);
 void xfs_attr_intent_destroy_cache(void);
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index c47fad39744e..e54a8372a30a 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -948,14 +948,13 @@ xfs_attr_shortform_to_leaf(
 		nargs.namelen = sfe->namelen;
 		nargs.value = &sfe->nameval[nargs.namelen];
 		nargs.valuelen = sfe->valuelen;
-		nargs.hashval = xfs_da_hashname(sfe->nameval,
-						sfe->namelen);
 		nargs.attr_filter = sfe->flags & XFS_ATTR_NSP_ONDISK_MASK;
 		if (!xfs_attr_check_namespace(sfe->flags)) {
 			xfs_da_mark_sick(args);
 			error = -EFSCORRUPTED;
 			goto out;
 		}
+		xfs_attr_sethash(&nargs);
 		error = xfs_attr3_leaf_lookup_int(bp, &nargs); /* set a->index */
 		ASSERT(error == -ENOATTR);
 		error = xfs_attr3_leaf_add(bp, &nargs);