Add a 'btrfs inspect-internal csum-dump' command to dump the on-disk
checksums of a file.
Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
Makefile | 3 +-
cmds-inspect-dump-csum.c | 266 +++++++++++++++++++++++++++++++++++++++++++++++
cmds-inspect.c | 2 +
commands.h | 2 +
4 files changed, 272 insertions(+), 1 deletion(-)
create mode 100644 cmds-inspect-dump-csum.c
diff --git a/Makefile b/Makefile
index e25e256f96af..f5d0c0532faf 100644
--- a/Makefile
+++ b/Makefile
@@ -130,7 +130,8 @@ cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
cmds-restore.o cmds-rescue.o chunk-recover.o super-recover.o \
cmds-property.o cmds-fi-usage.o cmds-inspect-dump-tree.o \
cmds-inspect-dump-super.o cmds-inspect-tree-stats.o cmds-fi-du.o \
- mkfs/common.o check/mode-common.o check/mode-lowmem.o
+ cmds-inspect-dump-csum.o mkfs/common.o check/mode-common.o \
+ check/mode-lowmem.o
libbtrfs_objects = send-stream.o send-utils.o kernel-lib/rbtree.o btrfs-list.o \
kernel-lib/crc32c.o messages.o \
uuid-tree.o utils-lib.o rbtree-utils.o
diff --git a/cmds-inspect-dump-csum.c b/cmds-inspect-dump-csum.c
new file mode 100644
index 000000000000..beb98abcf08b
--- /dev/null
+++ b/cmds-inspect-dump-csum.c
@@ -0,0 +1,266 @@
+/*
+ * Copyright (C) 2019 SUSE. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "ctree.h"
+#include "disk-io.h"
+#include "volumes.h"
+#include "help.h"
+#include "utils.h"
+
+#ifdef DEBUG
+#define pr_debug(fmt, ...) printf(fmt, __VA_ARGS__)
+#else
+#define pr_debug(fmt, ...) do {} while (0)
+#endif
+
+static int btrfs_lookup_csum(struct btrfs_root *root, struct btrfs_path *path,
+ u64 bytenr, u64 extent_len)
+{
+ struct btrfs_key key;
+ int pending_csums;
+ int total_csums;
+ u16 csum_size;
+ int ret;
+
+ key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
+ key.offset = bytenr;
+ key.type = BTRFS_EXTENT_CSUM_KEY;
+
+ csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0) {
+ goto out;
+ } else if (ret > 0) {
+ if (path->slots[0] == 0) {
+ ret = -ENOENT;
+ goto out;
+ } else {
+ path->slots[0]--;
+ }
+ }
+
+ pending_csums = total_csums = extent_len / 4096;
+
+ ret = -EINVAL;
+ while (pending_csums) {
+ struct extent_buffer *leaf;
+ struct btrfs_key found_key;
+ struct btrfs_csum_item *ci;
+ u32 item_size;
+ int nr_csums;
+ int slot;
+ int i;
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+ if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
+ goto out;
+
+ ci = btrfs_item_ptr(leaf, slot, struct btrfs_csum_item);
+ item_size = btrfs_item_size_nr(leaf, slot);
+
+ if (pending_csums < (item_size / 4))
+ nr_csums = pending_csums;
+ else
+ nr_csums = item_size / 4;
+
+ for (i = 0; i < nr_csums; i++) {
+ u32 csum;
+
+ read_extent_buffer(leaf, &csum,
+ (unsigned long) ci + i * 4,
+ csum_size);
+ printf("Disk Byte: %llu, Checksum: 0x%08x\n",
+ bytenr + i * 4096, csum);
+ }
+ pending_csums -= nr_csums;
+
+
+ ret = btrfs_next_item(root, path);
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ }
+
+out:
+ if (ret)
+ error("failed to lookup checksums for extent at %llu", bytenr);
+
+ return ret;
+}
+
+static int btrfs_get_extent_csum(struct btrfs_root *root,
+ struct btrfs_path *path, unsigned long ino)
+{
+ struct btrfs_fs_info *info = root->fs_info;
+ struct btrfs_key key;
+ int ret;
+
+ key.objectid = ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0) {
+ goto out;
+ } else if (ret > 0) {
+ if (path->slots[0] == 0) {
+ ret = -ENOENT;
+ goto out;
+ } else {
+ path->slots[0]--;
+ }
+ }
+
+ ret = -EINVAL;
+ while (1) {
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_path *csum_path;
+ struct extent_buffer *leaf;
+ struct btrfs_key found_key;
+ u64 extent_len;
+ u64 bytenr;
+ int slot;
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+ if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+ goto out;
+
+ fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+ extent_len = btrfs_file_extent_num_bytes(leaf, fi);
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+
+ pr_debug("extent start: %llu, len: %llu\n", bytenr, extent_len);
+
+ csum_path = btrfs_alloc_path();
+ ret = btrfs_lookup_csum(info->csum_root, csum_path, bytenr,
+ extent_len);
+ btrfs_release_path(csum_path);
+ if (ret) {
+ error("Error looking up checsum\n");
+ break;
+ }
+
+ ret = btrfs_next_item(root, path);
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ }
+
+out:
+ return ret;
+}
+
+const char * const cmd_inspect_dump_csum_usage[] = {
+ "btrfs inspect-internal dump-csum <path> <device>",
+ "Get Checksums for a given file",
+ NULL
+};
+
+int cmd_inspect_dump_csum(int argc, char **argv)
+{
+ struct btrfs_fs_info *info;
+ struct btrfs_root *root;
+ struct btrfs_path path;
+ struct stat sb;
+ char *filename;
+ u64 rootid;
+ int fd;
+ int ret;
+
+ ret = check_argc_exact(argc, 3);
+ if (ret)
+ usage(cmd_inspect_dump_csum_usage);
+
+ filename = argv[1];
+
+ info = open_ctree_fs_info(argv[2], 0, 0, 0, OPEN_CTREE_PARTIAL);
+ if (!info) {
+ error("unable to open device %s\n", argv[2]);
+ exit(1);
+ }
+
+ ret = stat(filename, &sb);
+ if (ret) {
+ error("cannot stat %s: %s\n", filename, strerror(errno));
+ exit(1);
+ }
+
+ if (sb.st_size < 1024) {
+ error("file smaller than 1KB, aborting\n");
+ exit(1);
+ }
+
+ fd = open(filename, O_RDONLY);
+ ret = lookup_path_rootid(fd, &rootid);
+ if (ret) {
+ error("error looking up subvolume for '%s'\n",
+ filename);
+ goto out_close;
+ }
+
+ pr_debug("%s: '%s' is on subvolume %llu\n", __func__, filename, rootid);
+
+ root = info->fs_root;
+
+ if (rootid != BTRFS_FS_TREE_OBJECTID) {
+ struct btrfs_key key;
+
+ key.objectid = rootid;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ root = btrfs_read_fs_root(info, &key);
+ if (IS_ERR(root)) {
+ error("unable to read root of subvolume '%llu'\n",
+ rootid);
+ goto out_close;
+ }
+ }
+
+ btrfs_init_path(&path);
+ ret = btrfs_get_extent_csum(root, &path, sb.st_ino);
+ btrfs_release_path(&path);
+ close_ctree(info->fs_root);
+ btrfs_close_all_devices();
+
+ if (ret)
+ error("checsum lookup for file %s (%lu) failed\n",
+ filename, sb.st_ino);
+out_close:
+ close(fd);
+ return ret;
+}
diff --git a/cmds-inspect.c b/cmds-inspect.c
index efea0331b7aa..c533e9f6dc0b 100644
--- a/cmds-inspect.c
+++ b/cmds-inspect.c
@@ -654,6 +654,8 @@ const struct cmd_group inspect_cmd_group = {
cmd_inspect_dump_super_usage, NULL, 0 },
{ "tree-stats", cmd_inspect_tree_stats,
cmd_inspect_tree_stats_usage, NULL, 0 },
+ { "dump-csum", cmd_inspect_dump_csum,
+ cmd_inspect_dump_csum_usage, NULL, 0 },
NULL_CMD_STRUCT
}
};
diff --git a/commands.h b/commands.h
index 76991f2b28d5..698ae532b2b8 100644
--- a/commands.h
+++ b/commands.h
@@ -92,6 +92,7 @@ extern const char * const cmd_rescue_usage[];
extern const char * const cmd_inspect_dump_super_usage[];
extern const char * const cmd_inspect_dump_tree_usage[];
extern const char * const cmd_inspect_tree_stats_usage[];
+extern const char * const cmd_inspect_dump_csum_usage[];
extern const char * const cmd_filesystem_du_usage[];
extern const char * const cmd_filesystem_usage_usage[];
@@ -108,6 +109,7 @@ int cmd_super_recover(int argc, char **argv);
int cmd_inspect(int argc, char **argv);
int cmd_inspect_dump_super(int argc, char **argv);
int cmd_inspect_dump_tree(int argc, char **argv);
+int cmd_inspect_dump_csum(int argc, char **argv);
int cmd_inspect_tree_stats(int argc, char **argv);
int cmd_property(int argc, char **argv);
int cmd_send(int argc, char **argv);
--
2.16.4
