[PATCH v4 45/46] btrfs: decrypt file names for send

[Josef Bacik <josef@xxxxxxxxxxxxxx>]

In send we're going to be looking up file names from back references and
putting them into the send stream.  If we are encrypted use the helper
for decrypting names and copy the decrypted name into the buffer.

Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
---
 fs/btrfs/send.c | 51 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 41 insertions(+), 10 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index ee5ea16423bb..de77321777f4 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -33,6 +33,7 @@
 #include "ioctl.h"
 #include "verity.h"
 #include "lru_cache.h"
+#include "fscrypt.h"
 
 /*
  * Maximum number of references an extent can have in order for us to attempt to
@@ -585,13 +586,42 @@ static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
 	return ret;
 }
 
-static int fs_path_add_from_extent_buffer(struct fs_path *p,
+static int fs_path_add_from_encrypted(struct btrfs_root *root,
+				      struct fs_path *p,
+				      struct extent_buffer *eb,
+				      unsigned long off, int len,
+				      u64 parent_ino)
+{
+	struct fscrypt_str fname = FSTR_INIT(NULL, 0);
+	int ret;
+
+	ret = fscrypt_fname_alloc_buffer(BTRFS_NAME_LEN, &fname);
+	if (ret)
+		return ret;
+
+	ret = btrfs_decrypt_name(root, eb, off, len, parent_ino, &fname);
+	if (ret)
+		goto out;
+
+	ret = fs_path_add(p, fname.name, fname.len);
+out:
+	fscrypt_fname_free_buffer(&fname);
+	return ret;
+}
+
+static int fs_path_add_from_extent_buffer(struct btrfs_root *root,
+					  struct fs_path *p,
 					  struct extent_buffer *eb,
-					  unsigned long off, int len)
+					  unsigned long off, int len,
+					  u64 parent_ino)
 {
 	int ret;
 	char *prepared;
 
+	if (root && btrfs_fs_incompat(root->fs_info, ENCRYPT))
+		return fs_path_add_from_encrypted(root, p, eb, off, len,
+						  parent_ino);
+
 	ret = fs_path_prepare_for_add(p, len, &prepared);
 	if (ret < 0)
 		goto out;
@@ -1074,8 +1104,8 @@ static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path,
 			}
 			p->start = start;
 		} else {
-			ret = fs_path_add_from_extent_buffer(p, eb, name_off,
-							     name_len);
+			ret = fs_path_add_from_extent_buffer(root, p, eb, name_off,
+							     name_len, dir);
 			if (ret < 0)
 				goto out;
 		}
@@ -1792,7 +1822,7 @@ static int read_symlink_unencrypted(struct btrfs_root *root, u64 ino,
 	off = btrfs_file_extent_inline_start(ei);
 	len = btrfs_file_extent_ram_bytes(path->nodes[0], ei);
 
-	ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);
+	ret = fs_path_add_from_extent_buffer(NULL, dest, path->nodes[0], off, len, 0);
 
 out:
 	btrfs_free_path(path);
@@ -2090,18 +2120,19 @@ static int get_first_ref(struct btrfs_root *root, u64 ino,
 		iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 				      struct btrfs_inode_ref);
 		len = btrfs_inode_ref_name_len(path->nodes[0], iref);
-		ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
-						     (unsigned long)(iref + 1),
-						     len);
 		parent_dir = found_key.offset;
+		ret = fs_path_add_from_extent_buffer(root, name, path->nodes[0],
+						     (unsigned long)(iref + 1),
+						     len, parent_dir);
 	} else {
 		struct btrfs_inode_extref *extref;
 		extref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 					struct btrfs_inode_extref);
 		len = btrfs_inode_extref_name_len(path->nodes[0], extref);
-		ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
-					(unsigned long)&extref->name, len);
 		parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref);
+		ret = fs_path_add_from_extent_buffer(root, name, path->nodes[0],
+					(unsigned long)&extref->name, len,
+					parent_dir);
 	}
 	if (ret < 0)
 		goto out;
-- 
2.41.0