From 8c3429300181be44b30f9f017d53dc717da56caa Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Mon, 3 Oct 2011 23:22:31 -0400 Subject: [PATCH] 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: Jeff Mahoney --- fs/btrfs/ctree.h | 11 +++++++++++ fs/btrfs/super.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 60 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 80b6486fd5e6..a97a67089755 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -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); diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 3ce97b217cbe..9774e38a0532 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -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 = ""; + 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; }