Commit 74ef0018 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: introduce "rescue=" mount option 



This patch introduces a new "rescue=" mount option group for all mount
options for data recovery.

Different rescue sub options are seperated by ':'. E.g
"ro,rescue=nologreplay:usebackuproot".

The original plan was to use ';', but ';' needs to be escaped/quoted,
or it will be interpreted by bash, similar to '|'.

And obviously, user can specify rescue options one by one like:
"ro,rescue=nologreplay,rescue=usebackuproot".

The following mount options are converted to "rescue=", old mount
options are deprecated but still available for compatibility purpose:

- usebackuproot
  Now it's "rescue=usebackuproot"

- nologreplay
  Now it's "rescue=nologreplay"

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a89ef455

fs/btrfs/super.c

+73 −8
Original line number Diff line number Diff line
@@ -326,7 +326,6 @@ enum { 
	Opt_defrag, Opt_nodefrag,

	Opt_discard, Opt_nodiscard,

	Opt_discard_mode,

	Opt_nologreplay,

	Opt_norecovery,

	Opt_ratio,

	Opt_rescan_uuid_tree,
@@ -340,9 +339,13 @@ enum { 
	Opt_subvolid,

	Opt_thread_pool,

	Opt_treelog, Opt_notreelog,

	Opt_usebackuproot,

	Opt_user_subvol_rm_allowed,



	/* Rescue options */

	Opt_rescue,

	Opt_usebackuproot,

	Opt_nologreplay,



	/* Deprecated options */

	Opt_alloc_start,

	Opt_recovery,
@@ -390,7 +393,6 @@ static const match_table_t tokens = { 
	{Opt_discard, "discard"},

	{Opt_discard_mode, "discard=%s"},

	{Opt_nodiscard, "nodiscard"},

	{Opt_nologreplay, "nologreplay"},

	{Opt_norecovery, "norecovery"},

	{Opt_ratio, "metadata_ratio=%u"},

	{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
@@ -408,9 +410,15 @@ static const match_table_t tokens = { 
	{Opt_thread_pool, "thread_pool=%u"},

	{Opt_treelog, "treelog"},

	{Opt_notreelog, "notreelog"},

	{Opt_usebackuproot, "usebackuproot"},

	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},



	/* Rescue options */

	{Opt_rescue, "rescue=%s"},

	/* Deprecated, with alias rescue=nologreplay */

	{Opt_nologreplay, "nologreplay"},

	/* Deprecated, with alias rescue=usebackuproot */

	{Opt_usebackuproot, "usebackuproot"},



	/* Deprecated options */

	{Opt_alloc_start, "alloc_start=%s"},

	{Opt_recovery, "recovery"},
@@ -433,6 +441,55 @@ static const match_table_t tokens = { 
	{Opt_err, NULL},

};



static const match_table_t rescue_tokens = {

	{Opt_usebackuproot, "usebackuproot"},

	{Opt_nologreplay, "nologreplay"},

	{Opt_err, NULL},

};



static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)

{

	char *opts;

	char *orig;

	char *p;

	substring_t args[MAX_OPT_ARGS];

	int ret = 0;



	opts = kstrdup(options, GFP_KERNEL);

	if (!opts)

		return -ENOMEM;

	orig = opts;



	while ((p = strsep(&opts, ":")) != NULL) {

		int token;



		if (!*p)

			continue;

		token = match_token(p, rescue_tokens, args);

		switch (token){

		case Opt_usebackuproot:

			btrfs_info(info,

				   "trying to use backup root at mount time");

			btrfs_set_opt(info->mount_opt, USEBACKUPROOT);

			break;

		case Opt_nologreplay:

			btrfs_set_and_info(info, NOLOGREPLAY,

					   "disabling log replay at mount time");

			break;

		case Opt_err:

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

			ret = -EINVAL;

			goto out;

		default:

			break;

		}



	}

out:

	kfree(orig);

	return ret;

}



/*

 * Regular mount options parser.  Everything that is needed only when

 * reading in a new superblock is parsed here.
@@ -689,6 +746,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, 
			break;

		case Opt_norecovery:

		case Opt_nologreplay:

			btrfs_warn(info,

		"'nologreplay' is deprecated, use 'rescue=nologreplay' instead");

			btrfs_set_and_info(info, NOLOGREPLAY,

					   "disabling log replay at mount time");

			break;
@@ -791,10 +850,11 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, 
					     "disabling auto defrag");

			break;

		case Opt_recovery:

			btrfs_warn(info,

				   "'recovery' is deprecated, use 'usebackuproot' instead");

			fallthrough;

		case Opt_usebackuproot:

			btrfs_warn(info,

			"'%s' is deprecated, use 'rescue=usebackuproot' instead",

				   token == Opt_recovery ? "recovery" :

				   "usebackuproot");

			btrfs_info(info,

				   "trying to use backup root at mount time");

			btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
@@ -859,6 +919,11 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, 
			}

			info->commit_interval = intarg;

			break;

		case Opt_rescue:

			ret = parse_rescue_options(info, args[0].from);

			if (ret < 0)

				goto out;

			break;

#ifdef CONFIG_BTRFS_DEBUG

		case Opt_fragment_all:

			btrfs_info(info, "fragmenting all space");
@@ -1344,7 +1409,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 
	if (btrfs_test_opt(info, NOTREELOG))

		seq_puts(seq, ",notreelog");

	if (btrfs_test_opt(info, NOLOGREPLAY))

		seq_puts(seq, ",nologreplay");

		seq_puts(seq, ",rescue=nologreplay");

	if (btrfs_test_opt(info, FLUSHONCOMMIT))

		seq_puts(seq, ",flushoncommit");

	if (btrfs_test_opt(info, DISCARD_SYNC))