btrfs: add error messages to all unrecognized mount options

Almost none of the errors stemming from a valid mount option but wrong
value prints a descriptive message which would help to identify why
mount failed. Like in the linked report:

  $ uname -r
  v4.19
  $ mount -o compress=zstd /dev/sdb /mnt
  mount: /mnt: wrong fs type, bad option, bad superblock on
  /dev/sdb, missing codepage or helper program, or other error.
  $ dmesg
  ...
  BTRFS error (device sdb): open_ctree failed

Errors caused by memory allocation failures are left out as it's not a
user error so reporting that would be confusing.

Link: https://lore.kernel.org/linux-btrfs/9c3fec36-fc61-3a33-4977-a7e207c3fa4e@gmx.de/
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 1387fbe..6627dd7 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -763,6 +763,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                                compress_force = false;
                                no_compress++;
                        } else {
+                               btrfs_err(info, "unrecognized compression value %s",
+                                         args[0].from);
                                ret = -EINVAL;
                                goto out;
                        }
@@ -821,8 +823,11 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                case Opt_thread_pool:
                        ret = match_int(&args[0], &intarg);
                        if (ret) {
+                               btrfs_err(info, "unrecognized thread_pool value %s",
+                                         args[0].from);
                                goto out;
                        } else if (intarg == 0) {
+                               btrfs_err(info, "invalid value 0 for thread_pool");
                                ret = -EINVAL;
                                goto out;
                        }
@@ -883,8 +888,11 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                        break;
                case Opt_ratio:
                        ret = match_int(&args[0], &intarg);
-                       if (ret)
+                       if (ret) {
+                               btrfs_err(info, "unrecognized metadata_ratio value %s",
+                                         args[0].from);
                                goto out;
+                       }
                        info->metadata_ratio = intarg;
                        btrfs_info(info, "metadata ratio %u",
                                   info->metadata_ratio);
@@ -901,6 +909,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                                btrfs_set_and_info(info, DISCARD_ASYNC,
                                                   "turning on async discard");
                        } else {
+                               btrfs_err(info, "unrecognized discard mode value %s",
+                                         args[0].from);
                                ret = -EINVAL;
                                goto out;
                        }
@@ -933,6 +943,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                                btrfs_set_and_info(info, FREE_SPACE_TREE,
                                                   "enabling free space tree");
                        } else {
+                               btrfs_err(info, "unrecognized space_cache value %s",
+                                         args[0].from);
                                ret = -EINVAL;
                                goto out;
                        }
@@ -1014,8 +1026,12 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                        break;
                case Opt_check_integrity_print_mask:
                        ret = match_int(&args[0], &intarg);
-                       if (ret)
+                       if (ret) {
+                               btrfs_err(info,
+                               "unrecognized check_integrity_print_mask value %s",
+                                       args[0].from);
                                goto out;
+                       }
                        info->check_integrity_print_mask = intarg;
                        btrfs_info(info, "check_integrity_print_mask 0x%x",
                                   info->check_integrity_print_mask);
@@ -1030,13 +1046,15 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                        goto out;
 #endif
                case Opt_fatal_errors:
-                       if (strcmp(args[0].from, "panic") == 0)
+                       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)
+                       } else if (strcmp(args[0].from, "bug") == 0) {
                                btrfs_clear_opt(info->mount_opt,
                                              PANIC_ON_FATAL_ERROR);
-                       else {
+                       } else {
+                               btrfs_err(info, "unrecognized fatal_errors value %s",
+                                         args[0].from);
                                ret = -EINVAL;
                                goto out;
                        }
@@ -1044,8 +1062,12 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                case Opt_commit_interval:
                        intarg = 0;
                        ret = match_int(&args[0], &intarg);
-                       if (ret)
+                       if (ret) {
+                               btrfs_err(info, "unrecognized commit_interval value %s",
+                                         args[0].from);
+                               ret = -EINVAL;
                                goto out;
+                       }
                        if (intarg == 0) {
                                btrfs_info(info,
                                           "using default commit interval %us",
@@ -1059,8 +1081,11 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
                        break;
                case Opt_rescue:
                        ret = parse_rescue_options(info, args[0].from);
-                       if (ret < 0)
+                       if (ret < 0) {
+                               btrfs_err(info, "unrecognized rescue value %s",
+                                         args[0].from);
                                goto out;
+                       }
                        break;
 #ifdef CONFIG_BTRFS_DEBUG
                case Opt_fragment_all: