Commit 882dbe0c authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: introduce mount option rescue=ignoredatacsums 



There are cases where you can end up with bad data csums because of
misbehaving applications.  This happens when an application modifies a
buffer in-flight when doing an O_DIRECT write.  In order to recover the
file we need a way to turn off data checksums so you can copy the file
off, and then you can delete the file and restore it properly later.

Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 42437a63

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -1299,6 +1299,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info) 
#define BTRFS_MOUNT_REF_VERIFY		(1 << 28)

#define BTRFS_MOUNT_DISCARD_ASYNC	(1 << 29)

#define BTRFS_MOUNT_IGNOREBADROOTS	(1 << 30)

#define BTRFS_MOUNT_IGNOREDATACSUMS	(1 << 31)



#define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)

#define BTRFS_DEFAULT_MAX_INLINE	(2048)

fs/btrfs/disk-io.c

+12 −9
Original line number Diff line number Diff line
@@ -2329,6 +2329,8 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info) 
		btrfs_init_devices_late(fs_info);

	}



	/* If IGNOREDATACSUMS is set don't bother reading the csum root. */

	if (!btrfs_test_opt(fs_info, IGNOREDATACSUMS)) {

		location.objectid = BTRFS_CSUM_TREE_OBJECTID;

		root = btrfs_read_tree_root(tree_root, &location);

		if (IS_ERR(root)) {
@@ -2340,6 +2342,7 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info) 
			set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);

			fs_info->csum_root = root;

		}

	}



	/*

	 * This tree can share blocks with some other fs tree during relocation

fs/btrfs/super.c

+11 −1
Original line number Diff line number Diff line
@@ -361,6 +361,7 @@ enum { 
	Opt_usebackuproot,

	Opt_nologreplay,

	Opt_ignorebadroots,

	Opt_ignoredatacsums,



	/* Deprecated options */

	Opt_recovery,
@@ -458,6 +459,8 @@ static const match_table_t rescue_tokens = { 
	{Opt_nologreplay, "nologreplay"},

	{Opt_ignorebadroots, "ignorebadroots"},

	{Opt_ignorebadroots, "ibadroots"},

	{Opt_ignoredatacsums, "ignoredatacsums"},

	{Opt_ignoredatacsums, "idatacsums"},

	{Opt_err, NULL},

};
@@ -505,6 +508,10 @@ static int parse_rescue_options(struct btrfs_fs_info *info, const char *options) 
			btrfs_set_and_info(info, IGNOREBADROOTS,

					   "ignoring bad roots");

			break;

		case Opt_ignoredatacsums:

			btrfs_set_and_info(info, IGNOREDATACSUMS,

					   "ignoring data csums");

			break;

		case Opt_err:

			btrfs_info(info, "unrecognized rescue option '%s'", p);

			ret = -EINVAL;
@@ -991,7 +998,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, 
		goto out;



	if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||

	    check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots"))

	    check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||

	    check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))

		ret = -EINVAL;

out:

	if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
@@ -1449,6 +1457,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 
		print_rescue_option(seq, "usebackuproot", &printed);

	if (btrfs_test_opt(info, IGNOREBADROOTS))

		print_rescue_option(seq, "ignorebadroots", &printed);

	if (btrfs_test_opt(info, IGNOREDATACSUMS))

		print_rescue_option(seq, "ignoredatacsums", &printed);

	if (btrfs_test_opt(info, FLUSHONCOMMIT))

		seq_puts(seq, ",flushoncommit");

	if (btrfs_test_opt(info, DISCARD_SYNC))

fs/btrfs/sysfs.c

+1 −0
Original line number Diff line number Diff line
@@ -333,6 +333,7 @@ static const char *rescue_opts[] = { 
	"usebackuproot",

	"nologreplay",

	"ignorebadroots",

	"ignoredatacsums",

};



static ssize_t supported_rescue_options_show(struct kobject *kobj,