[PATCH 5/8] btrfs-progs: interpret encrypted file extents.

[Josef Bacik <josef@toxicpanda.com>]

From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>

Encrypted file extents now have the 'encryption' field set to a
encryption type plus a context length, and have an extent context
appended to the item.  This necessitates adjusting the struct to have a
variable-length fscrypt_context member at the end, and printing contexts
if one is provided.

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 check/main.c               | 12 +++++++++---
 kernel-shared/print-tree.c | 25 +++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/check/main.c b/check/main.c
index 0979a8c6..e841ae9c 100644
--- a/check/main.c
+++ b/check/main.c
@@ -1698,7 +1698,6 @@ static int process_file_extent(struct btrfs_root *root,
 			rec->errors |= I_ERR_BAD_FILE_EXTENT;
 		if (extent_type == BTRFS_FILE_EXTENT_PREALLOC &&
 		    (btrfs_file_extent_compression(eb, fi) ||
-		     btrfs_file_extent_encryption(eb, fi) ||
 		     btrfs_file_extent_other_encoding(eb, fi)))
 			rec->errors |= I_ERR_BAD_FILE_EXTENT;
 		if (compression && rec->nodatasum)
@@ -6352,6 +6351,7 @@ static int run_next_block(struct btrfs_root *root,
 		for (i = 0; i < nritems; i++) {
 			struct btrfs_file_extent_item *fi;
 			unsigned long inline_offset;
+			size_t extra_size = 0;
 
 			inline_offset = offsetof(struct btrfs_file_extent_item,
 						 disk_bytenr);
@@ -6487,13 +6487,19 @@ static int run_next_block(struct btrfs_root *root,
 				continue;
 
 			/* Prealloc/regular extent must have fixed item size */
+			if (btrfs_file_extent_encryption(buf, fi))
+				extra_size = btrfs_file_extent_encryption_info_size(buf, fi) +
+					sizeof(struct btrfs_encryption_info);
+
 			if (btrfs_item_size(buf, i) !=
-			    sizeof(struct btrfs_file_extent_item)) {
+			    (sizeof(struct btrfs_file_extent_item) +
+			     extra_size)) {
 				ret = -EUCLEAN;
 				error(
 			"invalid file extent item size, have %u expect %zu",
 					btrfs_item_size(buf, i),
-					sizeof(struct btrfs_file_extent_item));
+					sizeof(struct btrfs_file_extent_item) +
+					extra_size);
 				continue;
 			}
 			/* key.offset (file offset) must be aligned */
diff --git a/kernel-shared/print-tree.c b/kernel-shared/print-tree.c
index d7ffeccd..859eb015 100644
--- a/kernel-shared/print-tree.c
+++ b/kernel-shared/print-tree.c
@@ -356,6 +356,26 @@ static void compress_type_to_str(u8 compress_type, char *ret)
 	}
 }
 
+static void generate_encryption_string(struct extent_buffer *leaf,
+				       struct btrfs_file_extent_item *fi,
+				       char *ret)
+{
+	u8 policy = btrfs_file_extent_encryption(leaf, fi);
+	u32 ctxsize = btrfs_file_extent_encryption_ctx_size(leaf, fi);
+	const __u8 *ctx = (__u8 *)(leaf->data +
+				   btrfs_file_extent_encryption_ctx_offset(fi));
+
+	ret += sprintf(ret, "(%hhu, %u", policy, ctxsize);
+
+	if (ctxsize) {
+		int i;
+		ret += sprintf(ret, ": context ");
+		for (i = 0; i < ctxsize; i++)
+			ret += sprintf(ret, "%02hhx", ctx[i]);
+	}
+	sprintf(ret, ")");
+}
+
 static const char* file_extent_type_to_str(u8 type)
 {
 	switch (type) {
@@ -372,9 +392,11 @@ static void print_file_extent_item(struct extent_buffer *eb,
 {
 	unsigned char extent_type = btrfs_file_extent_type(eb, fi);
 	char compress_str[16];
+	char encrypt_str[16];
 
 	compress_type_to_str(btrfs_file_extent_compression(eb, fi),
 			     compress_str);
+	generate_encryption_string(eb, fi, encrypt_str);
 
 	printf("\t\tgeneration %llu type %hhu (%s)\n",
 			btrfs_file_extent_generation(eb, fi),
@@ -407,6 +429,9 @@ static void print_file_extent_item(struct extent_buffer *eb,
 	printf("\t\textent compression %hhu (%s)\n",
 			btrfs_file_extent_compression(eb, fi),
 			compress_str);
+	printf("\t\textent encryption %hhu (%s)\n",
+			btrfs_file_extent_encryption(eb, fi),
+			encrypt_str);
 }
 
 /* Caller should ensure sizeof(*ret) >= 16("DATA|TREE_BLOCK") */
-- 
2.41.0