Commit 8c342930 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by David Sterba
Browse files

btrfs: Add btrfs_panic() 



As part of the effort to eliminate BUG_ON as an error handling
technique, we need to determine which errors are actual logic errors,
which are on-disk corruption, and which are normal runtime errors
e.g. -ENOMEM.

Annotating these error cases is helpful to understand and report them.

This patch adds a btrfs_panic() routine that will either panic
or BUG depending on the new -ofatal_errors={panic,bug} mount option.
Since there are still so many BUG_ONs, it defaults to BUG for now but I
expect that to change once the error handling effort has made
significant progress.

Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
parent c16fa4f2

fs/btrfs/ctree.h

+11 −0
Original line number Diff line number Diff line
@@ -1503,6 +1503,7 @@ struct btrfs_ioctl_defrag_range_args { 
#define BTRFS_MOUNT_SKIP_BALANCE	(1 << 19)

#define BTRFS_MOUNT_CHECK_INTEGRITY	(1 << 20)

#define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)

#define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR	(1 << 22)



#define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)

#define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
@@ -2970,6 +2971,16 @@ do { \ 
		__btrfs_std_error((fs_info), __func__, __LINE__, (errno));\

} while (0)



void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,

		   unsigned int line, int errno, const char *fmt, ...);



#define btrfs_panic(fs_info, errno, fmt, args...)			\

do {									\

	struct btrfs_fs_info *_i = (fs_info);				\

	__btrfs_panic(_i, __func__, __LINE__, errno, fmt, ##args);	\

	BUG_ON(!(_i->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR));	\

} while (0)



/* acl.c */

#ifdef CONFIG_BTRFS_FS_POSIX_ACL

struct posix_acl *btrfs_get_acl(struct inode *inode, int type);

fs/btrfs/super.c

+49 −1
Original line number Diff line number Diff line
@@ -76,6 +76,9 @@ static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno, 
	case -EROFS:

		errstr = "Readonly filesystem";

		break;

	case -EEXIST:

		errstr = "Object already exists";

		break;

	default:

		if (nbuf) {

			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
@@ -145,6 +148,36 @@ void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 
	btrfs_handle_error(fs_info);

}



/*

 * __btrfs_panic decodes unexpected, fatal errors from the caller,

 * issues an alert, and either panics or BUGs, depending on mount options.

 */

void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,

		   unsigned int line, int errno, const char *fmt, ...)

{

	char nbuf[16];

	char *s_id = "<unknown>";

	const char *errstr;

	struct va_format vaf = { .fmt = fmt };

	va_list args;



	if (fs_info)

		s_id = fs_info->sb->s_id;



	va_start(args, fmt);

	vaf.va = &args;



	errstr = btrfs_decode_error(fs_info, errno, nbuf);

	if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR)

		panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",

			s_id, function, line, &vaf, errstr);



	printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",

	       s_id, function, line, &vaf, errstr);

	va_end(args);

	/* Caller calls BUG() */

}



static void btrfs_put_super(struct super_block *sb)

{

	(void)close_ctree(btrfs_sb(sb)->tree_root);
@@ -166,7 +199,7 @@ enum { 
	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,

	Opt_no_space_cache, Opt_recovery, Opt_skip_balance,

	Opt_check_integrity, Opt_check_integrity_including_extent_data,

	Opt_check_integrity_print_mask,

	Opt_check_integrity_print_mask, Opt_fatal_errors,

	Opt_err,

};
@@ -206,6 +239,7 @@ static match_table_t tokens = { 
	{Opt_check_integrity, "check_int"},

	{Opt_check_integrity_including_extent_data, "check_int_data"},

	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},

	{Opt_fatal_errors, "fatal_errors=%s"},

	{Opt_err, NULL},

};
@@ -438,6 +472,18 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) 
			ret = -EINVAL;

			goto out;

#endif

		case Opt_fatal_errors:

			if (strcmp(args[0].from, "panic") == 0)

				btrfs_set_opt(info->mount_opt,

					      PANIC_ON_FATAL_ERROR);

			else if (strcmp(args[0].from, "bug") == 0)

				btrfs_clear_opt(info->mount_opt,

					      PANIC_ON_FATAL_ERROR);

			else {

				ret = -EINVAL;

				goto out;

			}

			break;

		case Opt_err:

			printk(KERN_INFO "btrfs: unrecognized mount option "

			       "'%s'\n", p);
@@ -766,6 +812,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 
		seq_puts(seq, ",inode_cache");

	if (btrfs_test_opt(root, SKIP_BALANCE))

		seq_puts(seq, ",skip_balance");

	if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))

		seq_puts(seq, ",fatal_errors=panic");

	return 0;

}

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