After finding a super block in a device also validate its
checksum. This validation is done in the kernel but it was
missing in btrfs-progs.
The function btrfs_check_super_csum() is imported from the
file fs/btrfs/disk-io.c in the kernel source tree.
v2:
When finding the super block for a device ignore checksum
validation failures if we're running the btrfsck tool, the
restore or check commands of the btrfs tool, btrfs-debug-tree
or btrfs-find-root tools. For all cases, print a warning
message whenever the checksum validation fails, mentioning
the superblock offset and device path.
Signed-off-by: Filipe David Borba Manana <fdman...@gmail.com>
---
btrfs-debug-tree.c | 2 +-
btrfs-find-root.c | 8 ++--
cmds-check.c | 2 +-
cmds-device.c | 2 +-
cmds-filesystem.c | 2 +-
cmds-replace.c | 2 +-
cmds-restore.c | 2 +-
disk-io.c | 103 ++++++++++++++++++++++++++++++++++++++++------------
disk-io.h | 7 +++-
utils.c | 15 ++++----
utils.h | 4 +-
volumes.c | 6 ++-
volumes.h | 3 +-
13 files changed, 110 insertions(+), 48 deletions(-)
diff --git a/btrfs-debug-tree.c b/btrfs-debug-tree.c
index 74d4d66..6fa9e83 100644
--- a/btrfs-debug-tree.c
+++ b/btrfs-debug-tree.c
@@ -166,7 +166,7 @@ int main(int ac, char **av)
if (ac != 1)
print_usage();
- info = open_ctree_fs_info(av[optind], 0, 0, 0, 1);
+ info = open_ctree_fs_info(av[optind], 0, 0, 0, 1, 1);
if (!info) {
fprintf(stderr, "unable to open %s\n", av[optind]);
exit(1);
diff --git a/btrfs-find-root.c b/btrfs-find-root.c
index 810d835..d7abc8a 100644
--- a/btrfs-find-root.c
+++ b/btrfs-find-root.c
@@ -102,7 +102,7 @@ static struct btrfs_root *open_ctree_broken(int fd, const
char *device)
u64 features;
ret = btrfs_scan_one_device(fd, device, &fs_devices,
- &total_devs, BTRFS_SUPER_INFO_OFFSET);
+ &total_devs, BTRFS_SUPER_INFO_OFFSET, 1);
if (ret) {
fprintf(stderr, "No valid Btrfs found on %s\n", device);
@@ -110,7 +110,7 @@ static struct btrfs_root *open_ctree_broken(int fd, const
char *device)
}
if (total_devs != 1) {
- ret = btrfs_scan_for_fsid(fs_devices, total_devs, 1);
+ ret = btrfs_scan_for_fsid(fs_devices, total_devs, 1, 1);
if (ret)
goto out;
}
@@ -149,8 +149,8 @@ static struct btrfs_root *open_ctree_broken(int fd, const
char *device)
fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
disk_super = fs_info->super_copy;
- ret = btrfs_read_dev_super(fs_devices->latest_bdev,
- disk_super, BTRFS_SUPER_INFO_OFFSET);
+ ret = btrfs_read_dev_super(fs_devices->latest_bdev, device,
+ disk_super, BTRFS_SUPER_INFO_OFFSET, 1);
if (ret) {
printk("No valid btrfs found\n");
goto out_devices;
diff --git a/cmds-check.c b/cmds-check.c
index 68cdd52..7aa5e82 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -5185,7 +5185,7 @@ int cmd_check(int argc, char **argv)
return -EBUSY;
}
- info = open_ctree_fs_info(argv[optind], bytenr, 0, rw, 1);
+ info = open_ctree_fs_info(argv[optind], bytenr, 0, rw, 1, 1);
if (!info) {
fprintf(stderr, "Couldn't open file system\n");
return -EIO;
diff --git a/cmds-device.c b/cmds-device.c
index 41e79d3..723ce2e 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -203,7 +203,7 @@ static int cmd_scan_dev(int argc, char **argv)
printf("Scanning for Btrfs filesystems\n");
if(checklist)
- ret = btrfs_scan_block_devices(1);
+ ret = btrfs_scan_block_devices(1, 0);
else
ret = btrfs_scan_one_dir("/dev", 1);
if (ret){
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index f41a72a..2178986 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -257,7 +257,7 @@ static int cmd_show(int argc, char **argv)
usage(cmd_show_usage);
if(checklist)
- ret = btrfs_scan_block_devices(0);
+ ret = btrfs_scan_block_devices(0, 0);
else
ret = btrfs_scan_one_dir("/dev", 0);
diff --git a/cmds-replace.c b/cmds-replace.c
index 6397bb5..16b17f0 100644
--- a/cmds-replace.c
+++ b/cmds-replace.c
@@ -280,7 +280,7 @@ static int cmd_start_replace(int argc, char **argv)
goto leave_with_error;
}
ret = btrfs_scan_one_device(fddstdev, dstdev, &fs_devices_mnt,
- &total_devs, BTRFS_SUPER_INFO_OFFSET);
+ &total_devs, BTRFS_SUPER_INFO_OFFSET, 0);
if (ret >= 0 && !force_using_targetdev) {
fprintf(stderr,
"Error, target device %s contains filesystem, use '-f'
to force overwriting.\n",
diff --git a/cmds-restore.c b/cmds-restore.c
index eca528d..39f19cd 100644
--- a/cmds-restore.c
+++ b/cmds-restore.c
@@ -842,7 +842,7 @@ static struct btrfs_root *open_fs(const char *dev, u64
root_location,
for (i = super_mirror; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
- fs_info = open_ctree_fs_info(dev, bytenr, root_location, 0, 1);
+ fs_info = open_ctree_fs_info(dev, bytenr, root_location, 0, 1,
1);
if (fs_info)
break;
fprintf(stderr, "Could not open root, trying backup super\n");
diff --git a/disk-io.c b/disk-io.c
index 768adda..350daa1 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -801,7 +801,8 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info
*fs_info,
static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path,
u64 sb_bytenr,
u64 root_tree_bytenr, int writes,
- int partial)
+ int partial,
+ int ignore_sb_csum)
{
u32 sectorsize;
u32 nodesize;
@@ -830,7 +831,7 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const
char *path,
fprintf(stderr, "Warning, could not drop caches\n");
ret = btrfs_scan_one_device(fp, path, &fs_devices,
- &total_devs, sb_bytenr);
+ &total_devs, sb_bytenr, ignore_sb_csum);
if (ret) {
fprintf(stderr, "No valid Btrfs found on %s\n", path);
@@ -838,7 +839,7 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const
char *path,
}
if (total_devs != 1) {
- ret = btrfs_scan_for_fsid(fs_devices, total_devs, 1);
+ ret = btrfs_scan_for_fsid(fs_devices, total_devs, 1,
ignore_sb_csum);
if (ret)
goto out;
}
@@ -881,8 +882,8 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const
char *path,
fs_info->super_bytenr = sb_bytenr;
disk_super = fs_info->super_copy;
- ret = btrfs_read_dev_super(fs_devices->latest_bdev,
- disk_super, sb_bytenr);
+ ret = btrfs_read_dev_super(fs_devices->latest_bdev, path,
+ disk_super, sb_bytenr, ignore_sb_csum);
if (ret) {
printk("No valid btrfs found\n");
goto out_devices;
@@ -1048,7 +1049,8 @@ out:
struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
u64 sb_bytenr, u64 root_tree_bytenr,
- int writes, int partial)
+ int writes, int partial,
+ int ignore_sb_csum)
{
int fp;
struct btrfs_fs_info *info;
@@ -1063,7 +1065,7 @@ struct btrfs_fs_info *open_ctree_fs_info(const char
*filename,
return NULL;
}
info = __open_ctree_fd(fp, filename, sb_bytenr, root_tree_bytenr,
- writes, partial);
+ writes, partial, ignore_sb_csum);
close(fp);
return info;
}
@@ -1072,7 +1074,7 @@ struct btrfs_root *open_ctree(const char *filename, u64
sb_bytenr, int writes)
{
struct btrfs_fs_info *info;
- info = open_ctree_fs_info(filename, sb_bytenr, 0, writes, 0);
+ info = open_ctree_fs_info(filename, sb_bytenr, 0, writes, 0, 0);
if (!info)
return NULL;
return info->fs_root;
@@ -1082,53 +1084,106 @@ struct btrfs_root *open_ctree_fd(int fp, const char
*path, u64 sb_bytenr,
int writes)
{
struct btrfs_fs_info *info;
- info = __open_ctree_fd(fp, path, sb_bytenr, 0, writes, 0);
+ info = __open_ctree_fd(fp, path, sb_bytenr, 0, writes, 0, 0);
if (!info)
return NULL;
return info->fs_root;
}
-int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr)
+static int btrfs_check_super_csum(char *raw_disk_sb, const char *path)
+{
+ struct btrfs_super_block *disk_sb =
+ (struct btrfs_super_block *)raw_disk_sb;
+ u16 csum_type = btrfs_super_csum_type(disk_sb);
+ int ret = 0;
+
+ if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
+ u32 crc = ~(u32)0;
+ const int csum_size = sizeof(crc);
+ char result[csum_size];
+
+ /*
+ * The super_block structure does not span the whole
+ * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
+ * is filled with zeros and is included in the checkum.
+ */
+ crc = btrfs_csum_data(NULL, raw_disk_sb + BTRFS_CSUM_SIZE,
+ crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+ btrfs_csum_final(crc, result);
+
+ if (memcmp(raw_disk_sb, result, csum_size))
+ ret = 1;
+
+ if (ret && btrfs_super_generation(disk_sb) < 1) {
+ fprintf(stderr, "Super block CRCs don't match, "
+ "older mkfs detected\n");
+ ret = 0;
+ }
+ }
+
+ if (ret) {
+ fprintf(stderr,
+ "Super block checksum validation failed, offset %llu,"
+ " device %s\n",
+ (unsigned long long)btrfs_super_bytenr(disk_sb), path);
+ }
+
+ if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
+ fprintf(stderr, "Unsupported super block checksum algorithm
%u\n",
+ csum_type);
+ ret = 1;
+ }
+
+ return ret;
+}
+
+int btrfs_read_dev_super(int fd, const char *path,
+ struct btrfs_super_block *sb, u64 sb_bytenr,
+ int ignore_sb_csum)
{
u8 fsid[BTRFS_FSID_SIZE];
int fsid_is_initialized = 0;
- struct btrfs_super_block buf;
+ char buf[BTRFS_SUPER_INFO_SIZE];
+ struct btrfs_super_block *tmp_sb = (struct btrfs_super_block *)buf;
int i;
int ret;
u64 transid = 0;
u64 bytenr;
if (sb_bytenr != BTRFS_SUPER_INFO_OFFSET) {
- ret = pread64(fd, &buf, sizeof(buf), sb_bytenr);
+ ret = pread64(fd, buf, sizeof(buf), sb_bytenr);
if (ret < sizeof(buf))
return -1;
- if (btrfs_super_bytenr(&buf) != sb_bytenr ||
- buf.magic != cpu_to_le64(BTRFS_MAGIC))
+ if (btrfs_super_bytenr(tmp_sb) != sb_bytenr ||
+ tmp_sb->magic != cpu_to_le64(BTRFS_MAGIC) ||
+ (btrfs_check_super_csum(buf, path) && !ignore_sb_csum))
return -1;
- memcpy(sb, &buf, sizeof(*sb));
+ memcpy(sb, buf, sizeof(*sb));
return 0;
}
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
- ret = pread64(fd, &buf, sizeof(buf), bytenr);
+ ret = pread64(fd, buf, sizeof(buf), bytenr);
if (ret < sizeof(buf))
break;
- if (btrfs_super_bytenr(&buf) != bytenr )
+ if (btrfs_super_bytenr(tmp_sb) != bytenr )
continue;
/* if magic is NULL, the device was removed */
- if (buf.magic == 0 && i == 0)
+ if (tmp_sb->magic == 0 && i == 0)
return -1;
- if (buf.magic != cpu_to_le64(BTRFS_MAGIC))
+ if (tmp_sb->magic != cpu_to_le64(BTRFS_MAGIC))
+ continue;
+ if (btrfs_check_super_csum(buf, path) && !ignore_sb_csum)
continue;
if (!fsid_is_initialized) {
- memcpy(fsid, buf.fsid, sizeof(fsid));
+ memcpy(fsid, tmp_sb->fsid, sizeof(fsid));
fsid_is_initialized = 1;
- } else if (memcmp(fsid, buf.fsid, sizeof(fsid))) {
+ } else if (memcmp(fsid, tmp_sb->fsid, sizeof(fsid))) {
/*
* the superblocks (the original one and
* its backups) contain data of different
@@ -1137,9 +1192,9 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block
*sb, u64 sb_bytenr)
continue;
}
- if (btrfs_super_generation(&buf) > transid) {
- memcpy(sb, &buf, sizeof(*sb));
- transid = btrfs_super_generation(&buf);
+ if (btrfs_super_generation(tmp_sb) > transid) {
+ memcpy(sb, buf, sizeof(*sb));
+ transid = btrfs_super_generation(tmp_sb);
}
}
diff --git a/disk-io.h b/disk-io.h
index c29ee8e..f061998 100644
--- a/disk-io.h
+++ b/disk-io.h
@@ -52,12 +52,15 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path,
u64 sb_bytenr,
int writes);
struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
u64 sb_bytenr, u64 root_tree_bytenr,
- int writes, int partial);
+ int writes, int partial,
+ int ignore_sb_csum);
int close_ctree(struct btrfs_root *root);
int write_all_supers(struct btrfs_root *root);
int write_ctree_super(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
-int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr);
+int btrfs_read_dev_super(int fd, const char *path,
+ struct btrfs_super_block *sb, u64 sb_bytenr,
+ int ignore_sb_csum);
int btrfs_map_bh_to_logical(struct btrfs_root *root, struct extent_buffer *bh,
u64 logical);
struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
diff --git a/utils.c b/utils.c
index 7b4cd74..4c9e89a 100644
--- a/utils.c
+++ b/utils.c
@@ -923,12 +923,12 @@ int check_mounted_where(int fd, const char *file, char
*where, int size,
/* scan the initial device */
ret = btrfs_scan_one_device(fd, file, &fs_devices_mnt,
- &total_devs, BTRFS_SUPER_INFO_OFFSET);
+ &total_devs, BTRFS_SUPER_INFO_OFFSET, 1);
is_btrfs = (ret >= 0);
/* scan other devices */
if (is_btrfs && total_devs > 1) {
- if((ret = btrfs_scan_for_fsid(fs_devices_mnt, total_devs, 1)))
+ if((ret = btrfs_scan_for_fsid(fs_devices_mnt, total_devs, 1,
1)))
return ret;
}
@@ -1085,7 +1085,7 @@ again:
}
ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
&num_devices,
- BTRFS_SUPER_INFO_OFFSET);
+ BTRFS_SUPER_INFO_OFFSET, 0);
if (ret == 0 && run_ioctl > 0) {
btrfs_register_one_device(fullpath);
}
@@ -1111,11 +1111,11 @@ fail:
}
int btrfs_scan_for_fsid(struct btrfs_fs_devices *fs_devices, u64 total_devs,
- int run_ioctls)
+ int run_ioctls, int ignore_sb_csum)
{
int ret;
- ret = btrfs_scan_block_devices(run_ioctls);
+ ret = btrfs_scan_block_devices(run_ioctls, ignore_sb_csum);
if (ret)
ret = btrfs_scan_one_dir("/dev", run_ioctls);
return ret;
@@ -1350,7 +1350,7 @@ int set_label(const char *btrfs_dev, const char *label)
set_label_mounted(btrfs_dev, label);
}
-int btrfs_scan_block_devices(int run_ioctl)
+int btrfs_scan_block_devices(int run_ioctl, int ignore_sb_csum)
{
struct stat st;
@@ -1416,7 +1416,8 @@ scan_again:
}
ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
&num_devices,
- BTRFS_SUPER_INFO_OFFSET);
+ BTRFS_SUPER_INFO_OFFSET,
+ ignore_sb_csum);
if (ret == 0 && run_ioctl > 0) {
btrfs_register_one_device(fullpath);
}
diff --git a/utils.h b/utils.h
index 3c17e14..9c1a98e 100644
--- a/utils.h
+++ b/utils.h
@@ -36,7 +36,7 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
u64 block_count, u32 io_width, u32 io_align,
u32 sectorsize);
int btrfs_scan_for_fsid(struct btrfs_fs_devices *fs_devices, u64 total_devs,
- int run_ioctls);
+ int run_ioctls, int ignore_sb_csum);
void btrfs_register_one_device(char *fname);
int btrfs_scan_one_dir(char *dirname, int run_ioctl);
int check_mounted(const char *devicename);
@@ -46,7 +46,7 @@ int btrfs_device_already_in_root(struct btrfs_root *root, int
fd,
int super_offset);
char *pretty_sizes(u64 size);
int get_mountpt(char *dev, char *mntpt, size_t size);
-int btrfs_scan_block_devices(int run_ioctl);
+int btrfs_scan_block_devices(int run_ioctl, int ignore_sb_csum);
u64 parse_size(char *s);
int open_file_or_dir(const char *fname);
int get_device_info(int fd, u64 devid,
diff --git a/volumes.c b/volumes.c
index 061f094..3178281 100644
--- a/volumes.c
+++ b/volumes.c
@@ -213,7 +213,8 @@ fail:
int btrfs_scan_one_device(int fd, const char *path,
struct btrfs_fs_devices **fs_devices_ret,
- u64 *total_devs, u64 super_offset)
+ u64 *total_devs, u64 super_offset,
+ int ignore_sb_csum)
{
struct btrfs_super_block *disk_super;
char *buf;
@@ -227,7 +228,8 @@ int btrfs_scan_one_device(int fd, const char *path,
goto error;
}
disk_super = (struct btrfs_super_block *)buf;
- ret = btrfs_read_dev_super(fd, disk_super, super_offset);
+ ret = btrfs_read_dev_super(fd, path,
+ disk_super, super_offset, ignore_sb_csum);
if (ret < 0) {
ret = -EIO;
goto error_brelse;
diff --git a/volumes.h b/volumes.h
index 911f788..e8d1534 100644
--- a/volumes.h
+++ b/volumes.h
@@ -179,7 +179,8 @@ int btrfs_update_device(struct btrfs_trans_handle *trans,
struct btrfs_device *device);
int btrfs_scan_one_device(int fd, const char *path,
struct btrfs_fs_devices **fs_devices_ret,
- u64 *total_devs, u64 super_offset);
+ u64 *total_devs, u64 super_offset,
+ int ignore_sb_csum);
int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64
len);
int btrfs_bootstrap_super_map(struct btrfs_mapping_tree *map_tree,
struct btrfs_fs_devices *fs_devices);
--
1.7.9.5
--
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