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

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
......@@ -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);
......
......@@ -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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