On Sun, Feb 11, 2024 at 8:44 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> On Sun, Feb 11, 2024 at 10:00:03AM +0200, Amir Goldstein wrote:
>
> > > whole d_genocide() thing is quite likely to disappear, turning
> > > kill_litter_super() into an alias for kill_anon_super().
> >
> > 2-in-1, getting rid of cruelty in the human and animal kingdom ;)
>
> FWIW, "litter" in the above is in the sense of "trash", not "collection
> of animal offspring from the same birth"...
Well either way, it is not clear by this name when the function should be used.
The current documentation of when kill_litter_super() should be used is
"use it for fs that set FS_LITTER flag, oh, BTW, there is no FS_LITTER flag":
Documentation/filesystems/porting.rst:
---
new file_system_type method - kill_sb(superblock). If you are converting
an existing filesystem, set it according to ->fs_flags::
FS_REQUIRES_DEV - kill_block_super
FS_LITTER - kill_litter_super
neither - kill_anon_super
FS_LITTER is gone - just remove it from fs_flags.
---
If you are going to make kill_litter_super() an alias of kill_anon_super()
I suggest going the extra mile and replacing the remaining 30 instances of
kill_litter_super().
If the rules become straight forward for the default ->kill_sb(),
then maybe we should even make ->kill_sb() optional and do:
diff --git a/fs/super.c b/fs/super.c
index d35e85295489..6200cac0e4f8 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -458,6 +458,18 @@ static void kill_super_notify(struct super_block *sb)
super_wake(sb, SB_DEAD);
}
+static void kill_sb(struct super_block *s)
+{
+ struct file_system_type *fs = s->s_type;
+
+ if (fs->kill_sb)
+ fs->kill_sb(s);
+ else if (fs->fs_flags & FS_REQUIRES_DEV)
+ kill_block_super(s);
+ else
+ kill_anon_super(s);
+}
+
/**
* deactivate_locked_super - drop an active reference to superblock
* @s: superblock to deactivate
@@ -474,7 +486,7 @@ void deactivate_locked_super(struct super_block *s)
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
shrinker_free(s->s_shrink);
- fs->kill_sb(s);
+ kill_sb(s);
kill_super_notify(s);
--
Thanks,
Amir.
