[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 66 insertions, 2 deletions

diff --git a/fs/jffs2/malloc.c b/fs/jffs2/malloc.c
index 036cbd11c00..3d5b7ecfbf8 100644
--- a/fs/jffs2/malloc.c
+++ b/fs/jffs2/malloc.c
@@ -26,6 +26,10 @@ static kmem_cache_t *tmp_dnode_info_slab;
 static kmem_cache_t *raw_node_ref_slab;
 static kmem_cache_t *node_frag_slab;
 static kmem_cache_t *inode_cache_slab;
+#ifdef CONFIG_JFFS2_FS_XATTR
+static kmem_cache_t *xattr_datum_cache;
+static kmem_cache_t *xattr_ref_cache;
+#endif
 
 int __init jffs2_create_slab_caches(void)
 {
@@ -68,8 +72,24 @@ int __init jffs2_create_slab_caches(void)
 	inode_cache_slab = kmem_cache_create("jffs2_inode_cache",
 					     sizeof(struct jffs2_inode_cache),
 					     0, 0, NULL, NULL);
-	if (inode_cache_slab)
-		return 0;
+	if (!inode_cache_slab)
+		goto err;
+
+#ifdef CONFIG_JFFS2_FS_XATTR
+	xattr_datum_cache = kmem_cache_create("jffs2_xattr_datum",
+					     sizeof(struct jffs2_xattr_datum),
+					     0, 0, NULL, NULL);
+	if (!xattr_datum_cache)
+		goto err;
+
+	xattr_ref_cache = kmem_cache_create("jffs2_xattr_ref",
+					   sizeof(struct jffs2_xattr_ref),
+					   0, 0, NULL, NULL);
+	if (!xattr_ref_cache)
+		goto err;
+#endif
+
+	return 0;
  err:
 	jffs2_destroy_slab_caches();
 	return -ENOMEM;
@@ -91,6 +111,12 @@ void jffs2_destroy_slab_caches(void)
 		kmem_cache_destroy(node_frag_slab);
 	if(inode_cache_slab)
 		kmem_cache_destroy(inode_cache_slab);
+#ifdef CONFIG_JFFS2_FS_XATTR
+	if (xattr_datum_cache)
+		kmem_cache_destroy(xattr_datum_cache);
+	if (xattr_ref_cache)
+		kmem_cache_destroy(xattr_ref_cache);
+#endif
 }
 
 struct jffs2_full_dirent *jffs2_alloc_full_dirent(int namesize)
@@ -205,3 +231,41 @@ void jffs2_free_inode_cache(struct jffs2_inode_cache *x)
 	dbg_memalloc("%p\n", x);
 	kmem_cache_free(inode_cache_slab, x);
 }
+
+#ifdef CONFIG_JFFS2_FS_XATTR
+struct jffs2_xattr_datum *jffs2_alloc_xattr_datum(void)
+{
+	struct jffs2_xattr_datum *xd;
+	xd = kmem_cache_alloc(xattr_datum_cache, GFP_KERNEL);
+	dbg_memalloc("%p\n", xd);
+
+	memset(xd, 0, sizeof(struct jffs2_xattr_datum));
+	xd->class = RAWNODE_CLASS_XATTR_DATUM;
+	INIT_LIST_HEAD(&xd->xindex);
+	return xd;
+}
+
+void jffs2_free_xattr_datum(struct jffs2_xattr_datum *xd)
+{
+	dbg_memalloc("%p\n", xd);
+	kmem_cache_free(xattr_datum_cache, xd);
+}
+
+struct jffs2_xattr_ref *jffs2_alloc_xattr_ref(void)
+{
+	struct jffs2_xattr_ref *ref;
+	ref = kmem_cache_alloc(xattr_ref_cache, GFP_KERNEL);
+	dbg_memalloc("%p\n", ref);
+
+	memset(ref, 0, sizeof(struct jffs2_xattr_ref));
+	ref->class = RAWNODE_CLASS_XATTR_REF;
+	INIT_LIST_HEAD(&ref->ilist);
+	return ref;
+}
+
+void jffs2_free_xattr_ref(struct jffs2_xattr_ref *ref)
+{
+	dbg_memalloc("%p\n", ref);
+	kmem_cache_free(xattr_ref_cache, ref);
+}
+#endif