On Thu, Oct 11, 2012 at 12:28 AM, David Sterba [off-list ref] wrote:

Hi,

On Wed, Oct 10, 2012 at 06:07:23PM +0800, zwu.kernel@gmail.com wrote:

quoted

--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h

@@ -1726,6 +1726,7 @@ struct btrfs_ioctl_defrag_range_args {
 #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_MOUNT_HOT_TRACK                (1 << 23)

Please don't forget to add new options to btrfs_show_options(),
otherwise we can't tell what filesystems have hot tracking enabled.

Great catch, thanks.

quoted

--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c

@@ -303,7 +304,7 @@ enum {
      Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
      Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
      Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
-     Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
+     Opt_no_space_cache, Opt_recovery, Opt_skip_balance, Opt_hot_track,

Please add the new option to the end.

OK.

quoted

      Opt_check_integrity, Opt_check_integrity_including_extent_data,
      Opt_check_integrity_print_mask, Opt_fatal_errors,
      Opt_err,

@@ -342,6 +343,7 @@ static match_table_t tokens = {
      {Opt_no_space_cache, "nospace_cache"},
      {Opt_recovery, "recovery"},
      {Opt_skip_balance, "skip_balance"},
+     {Opt_hot_track, "hot_track"},

(also this one)

ditto.

quoted

      {Opt_check_integrity, "check_int"},
      {Opt_check_integrity_including_extent_data, "check_int_data"},
      {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},

@@ -553,6 +555,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
              case Opt_skip_balance:
                      btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
                      break;
+             case Opt_hot_track:

It's a common patter in the surrounding code that a message is printed
when enabling options, but the vfs prints its own, so I'm not sure if
it's needed here as well. Just thinking, leave it as it is now.

OK

quoted

+                     btrfs_set_opt(info->mount_opt, HOT_TRACK);
+                     break;
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
              case Opt_check_integrity_including_extent_data:
                      printk(KERN_INFO "btrfs: enabling check integrity"

david

-- 
Regards,

Zhi Yong Wu