X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;ds=sidebyside;f=fs%2Fbtrfs%2Fxattr.c;h=193b58f7d3f3b36d027a85756c917aa7191f99b2;hb=e7874c996b8591f59d78efa519031dab5b58723b;hp=121c9550314f6a243eaf50ec70b6a6017ff9e368;hpb=33268eaf0b3db5e2bd12c0ada81a8e8f87a46d68;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 121c955..193b58f 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -21,146 +21,37 @@
 #include <linux/slab.h>
 #include <linux/rwsem.h>
 #include <linux/xattr.h>
+#include <linux/security.h>
 #include "ctree.h"
 #include "btrfs_inode.h"
 #include "transaction.h"
 #include "xattr.h"
 #include "disk-io.h"
 
-static struct xattr_handler *btrfs_xattr_handler_map[] = {
-	[BTRFS_XATTR_INDEX_USER]		= &btrfs_xattr_user_handler,
-#ifdef CONFIG_FS_POSIX_ACL
-	[BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS]	= &btrfs_xattr_acl_access_handler,
-	[BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT]	= &btrfs_xattr_acl_default_handler,
-#endif
-	[BTRFS_XATTR_INDEX_TRUSTED]		= &btrfs_xattr_trusted_handler,
-	[BTRFS_XATTR_INDEX_SECURITY]		= &btrfs_xattr_security_handler,
-	[BTRFS_XATTR_INDEX_SYSTEM]		= &btrfs_xattr_system_handler,
-};
-
-struct xattr_handler *btrfs_xattr_handlers[] = {
-	&btrfs_xattr_user_handler,
-#ifdef CONFIG_FS_POSIX_ACL
-	&btrfs_xattr_acl_access_handler,
-	&btrfs_xattr_acl_default_handler,
-#endif
-	&btrfs_xattr_trusted_handler,
-	&btrfs_xattr_security_handler,
-	&btrfs_xattr_system_handler,
-	NULL,
-};
 
-/*
- * @param name - the xattr name
- * @return - the xattr_handler for the xattr, NULL if its not found
- *
- * use this with listxattr where we don't already know the type of xattr we
- * have
- */
-static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l,
-						      unsigned long name_ptr,
-						      u16 name_len)
-{
-	struct xattr_handler *handler = NULL;
-	int i = 0;
-
-	for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++,
-	     handler = btrfs_xattr_handlers[i]) {
-		u16 prefix_len = strlen(handler->prefix);
-
-		if (name_len < prefix_len)
-			continue;
-
-		if (memcmp_extent_buffer(l, handler->prefix, name_ptr,
-					 prefix_len) == 0)
-			break;
-	}
-
-	return handler;
-}
-
-/*
- * @param name_index - the index for the xattr handler
- * @return the xattr_handler if we found it, NULL otherwise
- *
- * use this if we know the type of the xattr already
- */
-static struct xattr_handler *btrfs_xattr_handler(int name_index)
-{
-	struct xattr_handler *handler = NULL;
-
-	if (name_index >= 0 &&
-	    name_index < ARRAY_SIZE(btrfs_xattr_handler_map))
-		handler = btrfs_xattr_handler_map[name_index];
-
-	return handler;
-}
-
-static inline char *get_name(const char *name, int name_index)
-{
-	char *ret = NULL;
-	struct xattr_handler *handler = btrfs_xattr_handler(name_index);
-	int prefix_len;
-
-	if (!handler)
-		return ret;
-
-	prefix_len = strlen(handler->prefix);
-
-	ret = kmalloc(strlen(name) + prefix_len + 1, GFP_KERNEL);
-	if (!ret)
-		return ret;
-
-	memcpy(ret, handler->prefix, prefix_len);
-	memcpy(ret+prefix_len, name, strlen(name));
-	ret[prefix_len + strlen(name)] = '\0';
-
-	return ret;
-}
-
-size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
-				size_t list_size, const char *name,
-				size_t name_len)
-{
-	if (list && (name_len+1) <= list_size) {
-		memcpy(list, name, name_len);
-		list[name_len] = '\0';
-	} else
-		return -ERANGE;
-
-	return name_len+1;
-}
-
-ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
-			const char *attr_name, void *buffer, size_t size)
+ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
+				void *buffer, size_t size)
 {
 	struct btrfs_dir_item *di;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_path *path;
 	struct extent_buffer *leaf;
-	struct xattr_handler *handler = btrfs_xattr_handler(name_index);
 	int ret = 0;
 	unsigned long data_ptr;
-	char *name;
-
-	if (!handler)
-		return -EOPNOTSUPP;
-	name = get_name(attr_name, name_index);
-	if (!name)
-		return -ENOMEM;
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		kfree(name);
+	if (!path)
 		return -ENOMEM;
-	}
 
 	/* lookup the xattr by name */
 	di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
 				strlen(name), 0);
-	if (!di || IS_ERR(di)) {
+	if (!di) {
 		ret = -ENODATA;
 		goto out;
+	} else if (IS_ERR(di)) {
+		ret = PTR_ERR(di);
+		goto out;
 	}
 
 	leaf = path->nodes[0];
@@ -175,6 +66,14 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
 		ret = -ERANGE;
 		goto out;
 	}
+
+	/*
+	 * The way things are packed into the leaf is like this
+	 * |struct btrfs_dir_item|name|data|
+	 * where name is the xattr name, so security.foo, and data is the
+	 * content of the xattr.  data_ptr points to the location in memory
+	 * where the data starts in the in memory leaf
+	 */
 	data_ptr = (unsigned long)((char *)(di + 1) +
 				   btrfs_dir_name_len(leaf, di));
 	read_extent_buffer(leaf, buffer, data_ptr,
@@ -182,36 +81,26 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
 	ret = btrfs_dir_data_len(leaf, di);
 
 out:
-	kfree(name);
 	btrfs_free_path(path);
 	return ret;
 }
 
-int btrfs_xattr_set(struct inode *inode, int name_index,
-		    const char *attr_name, const void *value, size_t size,
-		    int flags)
+static int do_setxattr(struct btrfs_trans_handle *trans,
+		       struct inode *inode, const char *name,
+		       const void *value, size_t size, int flags)
 {
 	struct btrfs_dir_item *di;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct btrfs_trans_handle *trans;
 	struct btrfs_path *path;
-	struct xattr_handler *handler = btrfs_xattr_handler(name_index);
-	char *name;
-	int ret = 0, mod = 0;
-	if (!handler)
-		return -EOPNOTSUPP;
-	name = get_name(attr_name, name_index);
-	if (!name)
-		return -ENOMEM;
+	size_t name_len = strlen(name);
+	int ret = 0;
+
+	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
+		return -ENOSPC;
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		kfree(name);
+	if (!path)
 		return -ENOMEM;
-	}
-
-	trans = btrfs_start_transaction(root, 1);
-	btrfs_set_trans_block_group(trans, inode);
 
 	/* first lets see if we already have this xattr */
 	di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
@@ -230,15 +119,12 @@ int btrfs_xattr_set(struct inode *inode, int name_index,
 		}
 
 		ret = btrfs_delete_one_dir_name(trans, root, path, di);
-		if (ret)
-			goto out;
+		BUG_ON(ret);
 		btrfs_release_path(root, path);
 
 		/* if we don't have a value then we are removing the xattr */
-		if (!value) {
-			mod = 1;
+		if (!value)
 			goto out;
-		}
 	} else {
 		btrfs_release_path(root, path);
 
@@ -250,22 +136,45 @@ int btrfs_xattr_set(struct inode *inode, int name_index,
 	}
 
 	/* ok we have to create a completely new xattr */
-	ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
-				      value, size, inode->i_ino);
+	ret = btrfs_insert_xattr_item(trans, root, path, inode->i_ino,
+				      name, name_len, value, size);
+	BUG_ON(ret);
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+int __btrfs_setxattr(struct btrfs_trans_handle *trans,
+		     struct inode *inode, const char *name,
+		     const void *value, size_t size, int flags)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret;
+
+	if (trans)
+		return do_setxattr(trans, inode, name, value, size, flags);
+
+	ret = btrfs_reserve_metadata_space(root, 2);
 	if (ret)
-		goto out;
-	mod = 1;
+		return ret;
 
-out:
-	if (mod) {
-		inode->i_ctime = CURRENT_TIME;
-		ret = btrfs_update_inode(trans, root, inode);
+	trans = btrfs_start_transaction(root, 1);
+	if (!trans) {
+		ret = -ENOMEM;
+		goto out;
 	}
+	btrfs_set_trans_block_group(trans, inode);
 
-	btrfs_end_transaction(trans, root);
-	kfree(name);
-	btrfs_free_path(path);
+	ret = do_setxattr(trans, inode, name, value, size, flags);
+	if (ret)
+		goto out;
 
+	inode->i_ctime = CURRENT_TIME;
+	ret = btrfs_update_inode(trans, root, inode);
+	BUG_ON(ret);
+out:
+	btrfs_end_transaction_throttle(trans, root);
+	btrfs_unreserve_metadata_space(root, 2);
 	return ret;
 }
 
@@ -278,11 +187,10 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 	struct btrfs_item *item;
 	struct extent_buffer *leaf;
 	struct btrfs_dir_item *di;
-	struct xattr_handler *handler;
 	int ret = 0, slot, advance;
-	size_t total_size = 0, size_left = size, written;
+	size_t total_size = 0, size_left = size;
 	unsigned long name_ptr;
-	char *name;
+	size_t name_len;
 	u32 nritems;
 
 	/*
@@ -303,7 +211,6 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
 		goto err;
-	ret = 0;
 	advance = 0;
 	while (1) {
 		leaf = path->nodes[0];
@@ -344,37 +251,24 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 
 		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
 
-		total_size += btrfs_dir_name_len(leaf, di)+1;
+		name_len = btrfs_dir_name_len(leaf, di);
+		total_size += name_len + 1;
 
 		/* we are just looking for how big our buffer needs to be */
 		if (!size)
 			continue;
 
-		/* find our handler for this xattr */
-		name_ptr = (unsigned long)(di + 1);
-		handler = find_btrfs_xattr_handler(leaf, name_ptr,
-						   btrfs_dir_name_len(leaf, di));
-		if (!handler) {
-			printk(KERN_ERR "btrfs: unsupported xattr found\n");
-			continue;
-		}
-
-		name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL);
-		read_extent_buffer(leaf, name, name_ptr,
-				   btrfs_dir_name_len(leaf, di));
-
-		/* call the list function associated with this xattr */
-		written = handler->list(inode, buffer, size_left, name,
-					btrfs_dir_name_len(leaf, di));
-		kfree(name);
-
-		if (written < 0) {
+		if (!buffer || (name_len + 1) > size_left) {
 			ret = -ERANGE;
-			break;
+			goto err;
 		}
 
-		size_left -= written;
-		buffer += written;
+		name_ptr = (unsigned long)(di + 1);
+		read_extent_buffer(leaf, buffer, name_ptr, name_len);
+		buffer[name_len] = '\0';
+
+		size_left -= name_len + 1;
+		buffer += name_len + 1;
 	}
 	ret = total_size;
 
@@ -385,55 +279,114 @@ err:
 }
 
 /*
- * Handler functions
+ * List of handlers for synthetic system.* attributes.  All real ondisk
+ * attributes are handled directly.
  */
-#define BTRFS_XATTR_SETGET_FUNCS(name, index)				\
-static int btrfs_xattr_##name##_get(struct inode *inode,		\
-				    const char *name, void *value,	\
-				    size_t size)			\
-{									\
-	if (*name == '\0')						\
-		return -EINVAL;						\
-	return btrfs_xattr_get(inode, index, name, value, size);	\
-}									\
-static int btrfs_xattr_##name##_set(struct inode *inode,		\
-				    const char *name, const void *value,\
-				    size_t size, int flags)		\
-{									\
-	if (*name == '\0')						\
-		return -EINVAL;						\
-	return btrfs_xattr_set(inode, index, name, value, size, flags);	\
+struct xattr_handler *btrfs_xattr_handlers[] = {
+#ifdef CONFIG_BTRFS_FS_POSIX_ACL
+	&btrfs_xattr_acl_access_handler,
+	&btrfs_xattr_acl_default_handler,
+#endif
+	NULL,
+};
+
+/*
+ * Check if the attribute is in a supported namespace.
+ *
+ * This applied after the check for the synthetic attributes in the system
+ * namespace.
+ */
+static bool btrfs_is_valid_xattr(const char *name)
+{
+	return !strncmp(name, XATTR_SECURITY_PREFIX,
+			XATTR_SECURITY_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
 }
 
-BTRFS_XATTR_SETGET_FUNCS(security, BTRFS_XATTR_INDEX_SECURITY);
-BTRFS_XATTR_SETGET_FUNCS(system, BTRFS_XATTR_INDEX_SYSTEM);
-BTRFS_XATTR_SETGET_FUNCS(user, BTRFS_XATTR_INDEX_USER);
-BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED);
+ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
+		       void *buffer, size_t size)
+{
+	/*
+	 * If this is a request for a synthetic attribute in the system.*
+	 * namespace use the generic infrastructure to resolve a handler
+	 * for it via sb->s_xattr.
+	 */
+	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return generic_getxattr(dentry, name, buffer, size);
 
-struct xattr_handler btrfs_xattr_security_handler = {
-	.prefix = XATTR_SECURITY_PREFIX,
-	.list	= btrfs_xattr_generic_list,
-	.get	= btrfs_xattr_security_get,
-	.set	= btrfs_xattr_security_set,
-};
+	if (!btrfs_is_valid_xattr(name))
+		return -EOPNOTSUPP;
+	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
+}
 
-struct xattr_handler btrfs_xattr_system_handler = {
-	.prefix = XATTR_SYSTEM_PREFIX,
-	.list	= btrfs_xattr_generic_list,
-	.get	= btrfs_xattr_system_get,
-	.set	= btrfs_xattr_system_set,
-};
+int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+		   size_t size, int flags)
+{
+	/*
+	 * If this is a request for a synthetic attribute in the system.*
+	 * namespace use the generic infrastructure to resolve a handler
+	 * for it via sb->s_xattr.
+	 */
+	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return generic_setxattr(dentry, name, value, size, flags);
 
-struct xattr_handler btrfs_xattr_user_handler = {
-	.prefix	= XATTR_USER_PREFIX,
-	.list	= btrfs_xattr_generic_list,
-	.get	= btrfs_xattr_user_get,
-	.set	= btrfs_xattr_user_set,
-};
+	if (!btrfs_is_valid_xattr(name))
+		return -EOPNOTSUPP;
 
-struct xattr_handler btrfs_xattr_trusted_handler = {
-	.prefix = XATTR_TRUSTED_PREFIX,
-	.list	= btrfs_xattr_generic_list,
-	.get	= btrfs_xattr_trusted_get,
-	.set	= btrfs_xattr_trusted_set,
-};
+	if (size == 0)
+		value = "";  /* empty EA, do not remove */
+
+	return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
+				flags);
+}
+
+int btrfs_removexattr(struct dentry *dentry, const char *name)
+{
+	/*
+	 * If this is a request for a synthetic attribute in the system.*
+	 * namespace use the generic infrastructure to resolve a handler
+	 * for it via sb->s_xattr.
+	 */
+	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return generic_removexattr(dentry, name);
+
+	if (!btrfs_is_valid_xattr(name))
+		return -EOPNOTSUPP;
+
+	return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
+				XATTR_REPLACE);
+}
+
+int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
+			      struct inode *inode, struct inode *dir)
+{
+	int err;
+	size_t len;
+	void *value;
+	char *suffix;
+	char *name;
+
+	err = security_inode_init_security(inode, dir, &suffix, &value, &len);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return 0;
+		return err;
+	}
+
+	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
+		       GFP_NOFS);
+	if (!name) {
+		err = -ENOMEM;
+	} else {
+		strcpy(name, XATTR_SECURITY_PREFIX);
+		strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
+		err = __btrfs_setxattr(trans, inode, name, value, len, 0);
+		kfree(name);
+	}
+
+	kfree(suffix);
+	kfree(value);
+	return err;
+}