> This also removes all the superflous freezer calls on all filesystems
> as they are no longer needed as the VFS now performs filesystem
> freezing/thaw if the filesystem has support for it. The filesystem
> therefore is in charge of properly dealing with quiescing of the
> filesystem through its callbacks.
Can you split that out from the main logic change? Maybe even into one
patch per file system?
> +#ifdef CONFIG_PM_SLEEP
> +static bool super_should_freeze(struct super_block *sb)
> +{
> + if (!sb->s_root)
> + return false;
> + if (!(sb->s_flags & MS_BORN))
> + return false;
This is already done in the iterate_supers_excl and
iterate_supers_reverse_excl helpers that this helper is always called
through.
> + /*
> + * We don't freeze virtual filesystems, we skip those filesystems with
> + * no backing device.
> + */
> + if (sb->s_bdi == &noop_backing_dev_info)
> + return false;
Why?
> + /* No need to freeze read-only filesystems */
> + if (sb_rdonly(sb))
> + return false;
freeze_super/thaw_super already takes care of read-only file systems,
and IMHO in a better way.
> + int error = 0;
> +
> + spin_lock(&sb_lock);
> + if (!super_should_freeze(sb))
> + goto out;
> +
> + pr_info("%s (%s): freezing\n", sb->s_type->name, sb->s_id);
> +
> + spin_unlock(&sb_lock);
I don't see how super_should_freeze needs sb_lock. But if it does
the lock should be taken in the function.
> + atomic_inc(&sb->s_active);
Doesn't this need a atomic_inc_not_zero if we're racing with a delayed
unmount?
> + error = freeze_locked_super(sb, false);
> + if (error)
> + atomic_dec(&sb->s_active);
And this really needs something like deactivate_locked_super.
> + spin_lock(&sb_lock);
> + if (error && error != -EBUSY)
> + pr_notice("%s (%s): Unable to freeze, error=%d",
> + sb->s_type->name, sb->s_id, error);
> +
> +out:
> + spin_unlock(&sb_lock);
Huh, what is the point of sb_lock here?
> +int fs_suspend_freeze(void)
> +{
> + return iterate_supers_reverse_excl(fs_suspend_freeze_sb, NULL);
> +}
I'd just fold this helper into its only caller.
> + error = __thaw_super_locked(sb, false);
> + if (!error)
> + atomic_dec(&sb->s_active);
> +
> + spin_lock(&sb_lock);
> + if (error && error != -EBUSY)
> + pr_notice("%s (%s): Unable to unfreeze, error=%d",
> + sb->s_type->name, sb->s_id, error);
> +
> +out:
> + spin_unlock(&sb_lock);
> + return error;
> +}
> +
> +int fs_resume_unfreeze(void)
> +{
> + return iterate_supers_excl(fs_suspend_thaw_sb, NULL);
> +}
Same comments as on the freeze side.
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