1 files changed, 121 insertions, 63 deletions

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 5366fe4..60ff45e 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -102,48 +102,82 @@ static int do_setxattr(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	/* first lets see if we already have this xattr */
-	di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
-				strlen(name), -1);
-	if (IS_ERR(di)) {
-		ret = PTR_ERR(di);
-		goto out;
-	}
-
-	/* ok we already have this xattr, lets remove it */
-	if (di) {
-		/* if we want create only exit */
-		if (flags & XATTR_CREATE) {
-			ret = -EEXIST;
+	if (flags & XATTR_REPLACE) {
+		di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
+					name_len, -1);
+		if (IS_ERR(di)) {
+			ret = PTR_ERR(di);
+			goto out;
+		} else if (!di) {
+			ret = -ENODATA;
 			goto out;
 		}
-
 		ret = btrfs_delete_one_dir_name(trans, root, path, di);
-		BUG_ON(ret);
+		if (ret)
+			goto out;
 		btrfs_release_path(path);
 
-		/* if we don't have a value then we are removing the xattr */
+		/*
+		 * remove the attribute
+		 */
 		if (!value)
 			goto out;
-	} else {
+	}
+
+again:
+	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
+				      name, name_len, value, size);
+	/*
+	 * If we're setting an xattr to a new value but the new value is say
+	 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
+	 * back from split_leaf.  This is because it thinks we'll be extending
+	 * the existing item size, but we're asking for enough space to add the
+	 * item itself.  So if we get EOVERFLOW just set ret to EEXIST and let
+	 * the rest of the function figure it out.
+	 */
+	if (ret == -EOVERFLOW)
+		ret = -EEXIST;
+
+	if (ret == -EEXIST) {
+		if (flags & XATTR_CREATE)
+			goto out;
+		/*
+		 * We can't use the path we already have since we won't have the
+		 * proper locking for a delete, so release the path and
+		 * re-lookup to delete the thing.
+		 */
 		btrfs_release_path(path);
+		di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
+					name, name_len, -1);
+		if (IS_ERR(di)) {
+			ret = PTR_ERR(di);
+			goto out;
+		} else if (!di) {
+			/* Shouldn't happen but just in case... */
+			btrfs_release_path(path);
+			goto again;
+		}
 
-		if (flags & XATTR_REPLACE) {
-			/* we couldn't find the attr to replace */
-			ret = -ENODATA;
+		ret = btrfs_delete_one_dir_name(trans, root, path, di);
+		if (ret)
 			goto out;
+
+		/*
+		 * We have a value to set, so go back and try to insert it now.
+		 */
+		if (value) {
+			btrfs_release_path(path);
+			goto again;
 		}
 	}
-
-	/* ok we have to create a completely new xattr */
-	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
-				      name, name_len, value, size);
-	BUG_ON(ret);
 out:
 	btrfs_free_path(path);
 	return ret;
 }
 
+/*
+ * @value: "" makes the attribute to empty, NULL removes it
+ */
 int __btrfs_setxattr(struct btrfs_trans_handle *trans,
 		     struct inode *inode, const char *name,
 		     const void *value, size_t size, int flags)
@@ -276,21 +310,40 @@ const struct xattr_handler *btrfs_xattr_handlers[] = {
 /*
  * Check if the attribute is in a supported namespace.
  *
- * This applied after the check for the synthetic attributes in the system
+ * This is applied after the check for the synthetic attributes in the system
  * namespace.
  */
-static bool btrfs_is_valid_xattr(const char *name)
+static int 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);
+	int len = strlen(name);
+	int prefixlen = 0;
+
+	if (!strncmp(name, XATTR_SECURITY_PREFIX,
+			XATTR_SECURITY_PREFIX_LEN))
+		prefixlen = XATTR_SECURITY_PREFIX_LEN;
+	else if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		prefixlen = XATTR_SYSTEM_PREFIX_LEN;
+	else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
+		prefixlen = XATTR_TRUSTED_PREFIX_LEN;
+	else if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
+		prefixlen = XATTR_USER_PREFIX_LEN;
+	else
+		return -EOPNOTSUPP;
+
+	/*
+	 * The name cannot consist of just prefix
+	 */
+	if (len <= prefixlen)
+		return -EINVAL;
+
+	return 0;
 }
 
 ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
 		       void *buffer, size_t size)
 {
+	int ret;
+
 	/*
 	 * If this is a request for a synthetic attribute in the system.*
 	 * namespace use the generic infrastructure to resolve a handler
@@ -299,8 +352,9 @@ ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
 	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
 		return generic_getxattr(dentry, name, buffer, size);
 
-	if (!btrfs_is_valid_xattr(name))
-		return -EOPNOTSUPP;
+	ret = btrfs_is_valid_xattr(name);
+	if (ret)
+		return ret;
 	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
 }
 
@@ -308,6 +362,7 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 		   size_t size, int flags)
 {
 	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
+	int ret;
 
 	/*
 	 * The permission on security.* and system.* is not checked
@@ -324,8 +379,9 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
 		return generic_setxattr(dentry, name, value, size, flags);
 
-	if (!btrfs_is_valid_xattr(name))
-		return -EOPNOTSUPP;
+	ret = btrfs_is_valid_xattr(name);
+	if (ret)
+		return ret;
 
 	if (size == 0)
 		value = "";  /* empty EA, do not remove */
@@ -337,6 +393,7 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 int btrfs_removexattr(struct dentry *dentry, const char *name)
 {
 	struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
+	int ret;
 
 	/*
 	 * The permission on security.* and system.* is not checked
@@ -353,43 +410,44 @@ int btrfs_removexattr(struct dentry *dentry, const char *name)
 	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
 		return generic_removexattr(dentry, name);
 
-	if (!btrfs_is_valid_xattr(name))
-		return -EOPNOTSUPP;
+	ret = btrfs_is_valid_xattr(name);
+	if (ret)
+		return ret;
 
 	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,
-			      const struct qstr *qstr)
+int btrfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		     void *fs_info)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *suffix;
+	const struct xattr *xattr;
+	struct btrfs_trans_handle *trans = fs_info;
 	char *name;
+	int err = 0;
 
-	err = security_inode_init_security(inode, dir, qstr, &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 {
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
+			       strlen(xattr->name) + 1, GFP_NOFS);
+		if (!name) {
+			err = -ENOMEM;
+			break;
+		}
 		strcpy(name, XATTR_SECURITY_PREFIX);
-		strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
-		err = __btrfs_setxattr(trans, inode, name, value, len, 0);
+		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
+		err = __btrfs_setxattr(trans, inode, name,
+				       xattr->value, xattr->value_len, 0);
 		kfree(name);
+		if (err < 0)
+			break;
 	}
-
-	kfree(suffix);
-	kfree(value);
 	return err;
 }
+
+int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
+			      struct inode *inode, struct inode *dir,
+			      const struct qstr *qstr)
+{
+	return security_inode_init_security(inode, dir, qstr,
+					    &btrfs_initxattrs, trans);
+}