btrfs-progs: dump-tree: Introduce --nofilename option

In the mail list, it's pretty common that a developer is asking dump tree
output from the reporter, it's better to protect those kind reporters by
hiding the filename if the reporter wants.

This option will skip @name/@data output for the following items:
- DIR_INDEX
- DIR_ITEM
- INODE_REF

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Documentation/btrfs-inspect-internal.asciidoc

@@ -100,6 +100,9 @@ intermixed in the output
 +
 use breadth-first search to print trees, the nodes are printed before all
 leaves
+--nofilename::::
+do not print any filename of the filesystem. Useful for developer to inspect
+the filesystem while keep confidential info hiden.
 --noscan::::
 do not automatically scan the system for other devices from the same
 filesystem, only use the devices provided as the arguments

cmds/inspect-dump-tree.c

@@ -330,7 +330,7 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 	while (1) {
 		int c;
 		enum { GETOPT_VAL_FOLLOW = 256, GETOPT_VAL_DFS, GETOPT_VAL_BFS,
-		       GETOPT_VAL_NOSCAN};
+		       GETOPT_VAL_NOSCAN, GETOPT_VAL_NOFILENAME };
 		static const struct option long_options[] = {
 			{ "extents", no_argument, NULL, 'e'},
 			{ "device", no_argument, NULL, 'd'},
@@ -343,6 +343,8 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 			{ "bfs", no_argument, NULL, GETOPT_VAL_BFS },
 			{ "dfs", no_argument, NULL, GETOPT_VAL_DFS },
 			{ "noscan", no_argument, NULL, GETOPT_VAL_NOSCAN },
+			{ "nofilename", no_argument, NULL,
+				GETOPT_VAL_NOFILENAME },
 			{ NULL, 0, NULL, 0 }
 		};
 
@@ -410,6 +412,9 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 		case GETOPT_VAL_NOSCAN:
 			open_ctree_flags |= OPEN_CTREE_NO_DEVICES;
 			break;
+		case GETOPT_VAL_NOFILENAME:
+			open_ctree_flags |= OPEN_CTREE_DONT_PRINT_FILENAME;
+			break;
 		default:
 			usage_unknown_option(cmd, argv);
 		}

ctree.h

@@ -1193,6 +1193,7 @@ struct btrfs_fs_info {
 	unsigned int avoid_meta_chunk_alloc:1;
 	unsigned int avoid_sys_chunk_alloc:1;
 	unsigned int finalize_on_close:1;
+	unsigned int dont_print_filename:1;
 
 	int transaction_aborted;
 

disk-io.c

@@ -1218,6 +1218,8 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path,
 		fs_info->ignore_fsid_mismatch = 1;
 	if (flags & OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR)
 		fs_info->ignore_chunk_tree_error = 1;
+	if (flags & OPEN_CTREE_DONT_PRINT_FILENAME)
+		fs_info->dont_print_filename = 1;
 
 	if ((flags & OPEN_CTREE_RECOVER_SUPER)
 	     && (flags & OPEN_CTREE_TEMPORARY_SUPER)) {

disk-io.h

@@ -85,6 +85,9 @@ enum btrfs_open_ctree_flags {
 	 * compat_ro bit).
 	 */
 	OPEN_CTREE_INVALIDATE_FST = (1U << 13),
+
+	/* For print-tree only, skip filename output */
+	OPEN_CTREE_DONT_PRINT_FILENAME = (1U << 14),
 };
 
 /*

print-tree.c

@@ -67,16 +67,20 @@ static void print_dir_item(struct extent_buffer *eb, u32 size,
 		name_len = btrfs_dir_name_len(eb, di);
 		data_len = btrfs_dir_data_len(eb, di);
 		len = (name_len <= sizeof(namebuf))? name_len: sizeof(namebuf);
-		read_extent_buffer(eb, namebuf, (unsigned long)(di + 1), len);
 		printf("\t\ttransid %llu data_len %u name_len %u\n",
 				btrfs_dir_transid(eb, di),
 				data_len, name_len);
-		printf("\t\tname: %.*s\n", len, namebuf);
-		if (data_len) {
-			len = (data_len <= sizeof(namebuf))? data_len: sizeof(namebuf);
+		if (!(eb->fs_info && eb->fs_info->dont_print_filename)) {
 			read_extent_buffer(eb, namebuf,
-				(unsigned long)(di + 1) + name_len, len);
-			printf("\t\tdata %.*s\n", len, namebuf);
+					(unsigned long)(di + 1), len);
+			printf("\t\tname: %.*s\n", len, namebuf);
+			if (data_len) {
+				len = (data_len <= sizeof(namebuf))? data_len:
+					sizeof(namebuf);
+				read_extent_buffer(eb, namebuf,
+					(unsigned long)(di + 1) + name_len, len);
+				printf("\t\tdata %.*s\n", len, namebuf);
+			}
 		}
 		len = sizeof(*di) + name_len + data_len;
 		di = (struct btrfs_dir_item *)((char *)di + len);
@@ -101,12 +105,16 @@ static void print_inode_extref_item(struct extent_buffer *eb, u32 size,
 
 		len = (name_len <= sizeof(namebuf))? name_len: sizeof(namebuf);
 
-		read_extent_buffer(eb, namebuf, (unsigned long)(extref->name), len);
-
-		printf("\t\tindex %llu parent %llu namelen %u name: %.*s\n",
-		       (unsigned long long)index,
-		       (unsigned long long)parent_objid,
-		       name_len, len, namebuf);
+		if (eb->fs_info && eb->fs_info->dont_print_filename) {
+			printf("\t\tindex %llu [arent %llu namelen %u\n",
+				index, parent_objid, name_len);
+		} else {
+			read_extent_buffer(eb, namebuf,
+					(unsigned long)extref->name, len);
+			printf(
+			"\t\tindex %llu parent %llu namelen %u name: %.*s\n",
+				index, parent_objid, name_len, len, namebuf);
+		}
 
 		len = sizeof(*extref) + name_len;
 		extref = (struct btrfs_inode_extref *)((char *)extref + len);
@@ -127,9 +135,13 @@ static void print_inode_ref_item(struct extent_buffer *eb, u32 size,
 		name_len = btrfs_inode_ref_name_len(eb, ref);
 		index = btrfs_inode_ref_index(eb, ref);
 		len = (name_len <= sizeof(namebuf))? name_len: sizeof(namebuf);
-		read_extent_buffer(eb, namebuf, (unsigned long)(ref + 1), len);
-		printf("\t\tindex %llu namelen %u name: %.*s\n",
+		if (eb->fs_info && eb->fs_info->dont_print_filename) {
+			printf("\t\tindex %llu namelen %u\n", index, name_len);
+		} else {
+			read_extent_buffer(eb, namebuf, (unsigned long)(ref + 1), len);
+			printf("\t\tindex %llu namelen %u name: %.*s\n",
 		       (unsigned long long)index, name_len, len, namebuf);
+		}
 		len = sizeof(*ref) + name_len;
 		ref = (struct btrfs_inode_ref *)((char *)ref + len);
 		cur += len;