diff mbox series

[V3,RFC] xfsprogs: remove stubbed-out kernel functions out from xfs_shared.h

Message ID fa2fe2c5-645b-6263-3493-b59b4d096488@redhat.com (mailing list archive)
State New, archived
Headers show
Series [V3,RFC] xfsprogs: remove stubbed-out kernel functions out from xfs_shared.h | expand

Commit Message

Eric Sandeen Nov. 4, 2021, 5:15 p.m. UTC
Remove these kernel stubs by #ifdeffing code instead.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

Dave preferred #ifdefs over stubs, and this is what I came up with.

Honestly, I think this is worse, and will lead to more libxfs-sync pain
unless we're willing to scatter #ifdefs around the kernel code as well,
but I figured I'd put this out there for discussion.

Comments

Darrick J. Wong Nov. 4, 2021, 7:08 p.m. UTC | #1
On Thu, Nov 04, 2021 at 12:15:04PM -0500, Eric Sandeen wrote:
> Remove these kernel stubs by #ifdeffing code instead.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> Dave preferred #ifdefs over stubs, and this is what I came up with.
>
> Honestly, I think this is worse, and will lead to more libxfs-sync pain
> unless we're willing to scatter #ifdefs around the kernel code as well,
> but I figured I'd put this out there for discussion.

Yuck.  Now I wish I'd pushed back harder on the patch author (Dave) to
provide the xfsprogs version of this, or whatever fixes are needed to
libxfs-diff to deuglify whatever the result was, rather than let this
fall to the maintainer (Eric). :/

--D

> 
> diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
> index 9eda6eba..c01986f7 100644
> --- a/libxfs/xfs_ag.c
> +++ b/libxfs/xfs_ag.c
> @@ -170,7 +170,9 @@ __xfs_free_perag(
>  {
>  	struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
> +#ifdef __KERNEL__
>  	ASSERT(!delayed_work_pending(&pag->pag_blockgc_work));
> +#endif	/* __KERNEL__ */
>  	ASSERT(atomic_read(&pag->pag_ref) == 0);
>  	kmem_free(pag);
>  }
> @@ -192,9 +194,11 @@ xfs_free_perag(
>  		ASSERT(pag);
>  		ASSERT(atomic_read(&pag->pag_ref) == 0);
> +#ifdef __KERNEL__
>  		cancel_delayed_work_sync(&pag->pag_blockgc_work);
>  		xfs_iunlink_destroy(pag);
>  		xfs_buf_hash_destroy(pag);
> +#endif	/* __KERNEL__ */
>  		call_rcu(&pag->rcu_head, __xfs_free_perag);
>  	}
> @@ -246,6 +250,7 @@ xfs_initialize_perag(
>  		spin_unlock(&mp->m_perag_lock);
>  		radix_tree_preload_end();
> +#ifdef __KERNEL__
>  		/* Place kernel structure only init below this point. */
>  		spin_lock_init(&pag->pag_ici_lock);
>  		spin_lock_init(&pag->pagb_lock);
> @@ -267,6 +272,7 @@ xfs_initialize_perag(
>  		/* first new pag is fully initialized */
>  		if (first_initialised == NULLAGNUMBER)
>  			first_initialised = index;
> +#endif	/* __KERNEL__ */
>  	}
>  	index = xfs_set_inode_alloc(mp, agcount);
> @@ -277,10 +283,12 @@ xfs_initialize_perag(
>  	mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
>  	return 0;
> +#ifdef __KERNEL__
>  out_hash_destroy:
>  	xfs_buf_hash_destroy(pag);
>  out_remove_pag:
>  	radix_tree_delete(&mp->m_perag_tree, index);
> +#endif	/* __KERNEL__ */
>  out_free_pag:
>  	kmem_free(pag);
>  out_unwind_new_pags:
> diff --git a/libxfs/xfs_ag.h b/libxfs/xfs_ag.h
> index 4c6f9045..dda1303e 100644
> --- a/libxfs/xfs_ag.h
> +++ b/libxfs/xfs_ag.h
> @@ -64,6 +64,9 @@ struct xfs_perag {
>  	/* Blocks reserved for the reverse mapping btree. */
>  	struct xfs_ag_resv	pag_rmapbt_resv;
> +	/* for rcu-safe freeing */
> +	struct rcu_head	rcu_head;
> +
>  	/* -- kernel only structures below this line -- */
>  	/*
> @@ -75,6 +78,7 @@ struct xfs_perag {
>  	spinlock_t	pag_state_lock;
>  	spinlock_t	pagb_lock;	/* lock for pagb_tree */
> +#ifdef __KERNEL__
>  	struct rb_root	pagb_tree;	/* ordered tree of busy extents */
>  	unsigned int	pagb_gen;	/* generation count for pagb_tree */
>  	wait_queue_head_t pagb_wait;	/* woken when pagb_gen changes */
> @@ -90,9 +94,6 @@ struct xfs_perag {
>  	spinlock_t	pag_buf_lock;	/* lock for pag_buf_hash */
>  	struct rhashtable pag_buf_hash;
> -	/* for rcu-safe freeing */
> -	struct rcu_head	rcu_head;
> -
>  	/* background prealloc block trimming */
>  	struct delayed_work	pag_blockgc_work;
> @@ -102,6 +103,7 @@ struct xfs_perag {
>  	 * or have some other means to control concurrency.
>  	 */
>  	struct rhashtable	pagi_unlinked_hash;
> +#endif	/* __KERNEL__ */
>  };
>  int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
> diff --git a/libxfs/xfs_shared.h b/libxfs/xfs_shared.h
> index bafee48c..25c4cab5 100644
> --- a/libxfs/xfs_shared.h
> +++ b/libxfs/xfs_shared.h
> @@ -180,24 +180,4 @@ struct xfs_ino_geometry {
>  };
> -/* Faked up kernel bits */
> -struct rb_root {
> -};
> -
> -#define RB_ROOT 		(struct rb_root) { }
> -
> -typedef struct wait_queue_head {
> -} wait_queue_head_t;
> -
> -#define init_waitqueue_head(wqh)	do { } while(0)
> -
> -struct rhashtable {
> -};
> -
> -struct delayed_work {
> -};
> -
> -#define INIT_DELAYED_WORK(work, func)	do { } while(0)
> -#define cancel_delayed_work_sync(work)	do { } while(0)
> -
>  #endif /* __XFS_SHARED_H__ */
>
Dave Chinner Nov. 4, 2021, 10:38 p.m. UTC | #2
On Thu, Nov 04, 2021 at 12:15:04PM -0500, Eric Sandeen wrote:
> Remove these kernel stubs by #ifdeffing code instead.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> Dave preferred #ifdefs over stubs, and this is what I came up with.
> 
> Honestly, I think this is worse, and will lead to more libxfs-sync pain
> unless we're willing to scatter #ifdefs around the kernel code as well,
> but I figured I'd put this out there for discussion.
> 
> diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
> index 9eda6eba..c01986f7 100644
> --- a/libxfs/xfs_ag.c
> +++ b/libxfs/xfs_ag.c
> @@ -170,7 +170,9 @@ __xfs_free_perag(
>  {
>  	struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
> +#ifdef __KERNEL__
>  	ASSERT(!delayed_work_pending(&pag->pag_blockgc_work));
> +#endif	/* __KERNEL__ */
>  	ASSERT(atomic_read(&pag->pag_ref) == 0);
>  	kmem_free(pag);
>  }
> @@ -192,9 +194,11 @@ xfs_free_perag(
>  		ASSERT(pag);
>  		ASSERT(atomic_read(&pag->pag_ref) == 0);
> +#ifdef __KERNEL__
>  		cancel_delayed_work_sync(&pag->pag_blockgc_work);
>  		xfs_iunlink_destroy(pag);
>  		xfs_buf_hash_destroy(pag);
> +#endif	/* __KERNEL__ */
>  		call_rcu(&pag->rcu_head, __xfs_free_perag);
>  	}

These can be stubbed in libxfs_priv.h as we do with all other kernel
functions we don't use:

#define delayed_work_pending(a)		((void)0)
#define cancel_delayed_work_sync(a)	((void)0)
#define xfs_iunlink_destroy(a)		((void)0)
#define xfs_buf_hash_destroy(a)		((void)0)

That is the normal way we avoid needing these ifdef KERNEL clauses
in the libxfs C code. 

> @@ -246,6 +250,7 @@ xfs_initialize_perag(
>  		spin_unlock(&mp->m_perag_lock);
>  		radix_tree_preload_end();
> +#ifdef __KERNEL__
>  		/* Place kernel structure only init below this point. */
>  		spin_lock_init(&pag->pag_ici_lock);
>  		spin_lock_init(&pag->pagb_lock);
> @@ -267,6 +272,7 @@ xfs_initialize_perag(
>  		/* first new pag is fully initialized */
>  		if (first_initialised == NULLAGNUMBER)
>  			first_initialised = index;
> +#endif	/* __KERNEL__ */
>  	}

endif is in the wrong place - it needs to be before the
first_initialised checks because that is necessary for error
unwinding.

>  	index = xfs_set_inode_alloc(mp, agcount);
> @@ -277,10 +283,12 @@ xfs_initialize_perag(
>  	mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
>  	return 0;
> +#ifdef __KERNEL__
>  out_hash_destroy:
>  	xfs_buf_hash_destroy(pag);
>  out_remove_pag:
>  	radix_tree_delete(&mp->m_perag_tree, index);
> +#endif	/* __KERNEL__ */
>  out_free_pag:
>  	kmem_free(pag);
>  out_unwind_new_pags:

Again, stubbing out the functions like so:

#define xfs_buf_hash_init(a)		((void)0)
#define xfs_unlink_init(a)		((void)0)

means that the conditional init code doesn't need to be ifdef'd out
and so the error unwinding doesn't need to be ifdef'd out, either.
And, FWIW, you missed the xfs_buf_hash_destroy/xfs_iunlink_destroy
calls in the unwinding code....

> diff --git a/libxfs/xfs_ag.h b/libxfs/xfs_ag.h
> index 4c6f9045..dda1303e 100644
> --- a/libxfs/xfs_ag.h
> +++ b/libxfs/xfs_ag.h
> @@ -64,6 +64,9 @@ struct xfs_perag {
>  	/* Blocks reserved for the reverse mapping btree. */
>  	struct xfs_ag_resv	pag_rmapbt_resv;
> +	/* for rcu-safe freeing */
> +	struct rcu_head	rcu_head;
> +
>  	/* -- kernel only structures below this line -- */
>  	/*

Moving the rcu_head needs to be done in a separate patch, as that
needs to be done on the kernel side, too. When this change went into
the kernel, we didn't have userspace RCU so it was considered a
kernel only structure....

With those changes, we end up with some new stubs in libxfs_priv.h
and two places where we need #ifdef __KERNEL__ in xfs_ag.[ch]. Most
of the mess in this patch goes away....

Cheers,

Dave.
Eric Sandeen Nov. 5, 2021, 4:40 p.m. UTC | #3
On 11/4/21 5:38 PM, Dave Chinner wrote:

> With those changes, we end up with some new stubs in libxfs_priv.h
> and two places where we need #ifdef __KERNEL__ in xfs_ag.[ch]. Most
> of the mess in this patch goes away....
> 
> Cheers,
> 
> Dave.
Ok.

I will split this up into the right patch granularity, but is this the
endpoint you're looking for?  One #ifdef in each of xfs_ag.[ch], two total.

The delayed work init/cancel assymmetry is a little odd, but I'll
get over it.

diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
index 15bae1ff..2ca3b9b2 100644
--- a/libxfs/libxfs_priv.h
+++ b/libxfs/libxfs_priv.h
@@ -673,6 +673,9 @@ static inline void xfs_iunlink_destroy(struct xfs_perag *pag) { }
  xfs_agnumber_t xfs_set_inode_alloc(struct xfs_mount *mp,
  		xfs_agnumber_t agcount);
  
+/* Faked up kernel bits */
+#define cancel_delayed_work_sync(work) do { } while(0)
+
  /* Keep static checkers quiet about nonstatic functions by exporting */
  int xfs_rtbuf_get(struct xfs_mount *mp, struct xfs_trans *tp,
  		  xfs_rtblock_t block, int issum, struct xfs_buf **bpp);
diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
index 9eda6eba..149f9857 100644
--- a/libxfs/xfs_ag.c
+++ b/libxfs/xfs_ag.c
@@ -246,6 +246,7 @@ xfs_initialize_perag(
  		spin_unlock(&mp->m_perag_lock);
  		radix_tree_preload_end();
  
+#ifdef __KERNEL__
  		/* Place kernel structure only init below this point. */
  		spin_lock_init(&pag->pag_ici_lock);
  		spin_lock_init(&pag->pagb_lock);
@@ -255,6 +256,7 @@ xfs_initialize_perag(
  		init_waitqueue_head(&pag->pagb_wait);
  		pag->pagb_count = 0;
  		pag->pagb_tree = RB_ROOT;
+#endif	/* __KERNEL_ */
  
  		error = xfs_buf_hash_init(pag);
  		if (error)
diff --git a/libxfs/xfs_ag.h b/libxfs/xfs_ag.h
index 4c6f9045..ef04a537 100644
--- a/libxfs/xfs_ag.h
+++ b/libxfs/xfs_ag.h
@@ -64,8 +64,11 @@ struct xfs_perag {
  	/* Blocks reserved for the reverse mapping btree. */
  	struct xfs_ag_resv	pag_rmapbt_resv;
  
-	/* -- kernel only structures below this line -- */
+	/* for rcu-safe freeing */
+	struct rcu_head	rcu_head;
  
+#ifdef __KERNEL__
+	/* -- kernel only structures below this line -- */
  	/*
  	 * Bitsets of per-ag metadata that have been checked and/or are sick.
  	 * Callers should hold pag_state_lock before accessing this field.
@@ -90,9 +93,6 @@ struct xfs_perag {
  	spinlock_t	pag_buf_lock;	/* lock for pag_buf_hash */
  	struct rhashtable pag_buf_hash;
  
-	/* for rcu-safe freeing */
-	struct rcu_head	rcu_head;
-
  	/* background prealloc block trimming */
  	struct delayed_work	pag_blockgc_work;
  
@@ -102,6 +102,7 @@ struct xfs_perag {
  	 * or have some other means to control concurrency.
  	 */
  	struct rhashtable	pagi_unlinked_hash;
+#endif	/* __KERNEL__ */
  };
  
  int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
diff --git a/libxfs/xfs_shared.h b/libxfs/xfs_shared.h
index bafee48c..25c4cab5 100644
--- a/libxfs/xfs_shared.h
+++ b/libxfs/xfs_shared.h
@@ -180,24 +180,4 @@ struct xfs_ino_geometry {
  
  };
  
-/* Faked up kernel bits */
-struct rb_root {
-};
-
-#define RB_ROOT 		(struct rb_root) { }
-
-typedef struct wait_queue_head {
-} wait_queue_head_t;
-
-#define init_waitqueue_head(wqh)	do { } while(0)
-
-struct rhashtable {
-};
-
-struct delayed_work {
-};
-
-#define INIT_DELAYED_WORK(work, func)	do { } while(0)
-#define cancel_delayed_work_sync(work)	do { } while(0)
-
  #endif /* __XFS_SHARED_H__ */
Dave Chinner Nov. 7, 2021, 10:58 p.m. UTC | #4
On Fri, Nov 05, 2021 at 11:40:57AM -0500, Eric Sandeen wrote:
> On 11/4/21 5:38 PM, Dave Chinner wrote:
> 
> > With those changes, we end up with some new stubs in libxfs_priv.h
> > and two places where we need #ifdef __KERNEL__ in xfs_ag.[ch]. Most
> > of the mess in this patch goes away....
> > 
> > Cheers,
> > 
> > Dave.
> Ok.
> 
> I will split this up into the right patch granularity, but is this the
> endpoint you're looking for?  One #ifdef in each of xfs_ag.[ch], two total.

Yup.

> The delayed work init/cancel assymmetry is a little odd, but I'll
> get over it.
> 
> diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
> index 15bae1ff..2ca3b9b2 100644
> --- a/libxfs/libxfs_priv.h
> +++ b/libxfs/libxfs_priv.h
> @@ -673,6 +673,9 @@ static inline void xfs_iunlink_destroy(struct xfs_perag *pag) { }
>  xfs_agnumber_t xfs_set_inode_alloc(struct xfs_mount *mp,
>  		xfs_agnumber_t agcount);
> +/* Faked up kernel bits */
> +#define cancel_delayed_work_sync(work) do { } while(0)

Comment is completely redundant. libxfs_priv.h is entirely for
"faked up kernel bits".

I'd also put this up near the top of the file near the definition of
struct iomap, not place it randomly in amongst a bunch of XFS
definitions.

Cheers,

Dave.
diff mbox series

Patch

diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
index 9eda6eba..c01986f7 100644
--- a/libxfs/xfs_ag.c
+++ b/libxfs/xfs_ag.c
@@ -170,7 +170,9 @@  __xfs_free_perag(
  {
  	struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
  
+#ifdef __KERNEL__
  	ASSERT(!delayed_work_pending(&pag->pag_blockgc_work));
+#endif	/* __KERNEL__ */
  	ASSERT(atomic_read(&pag->pag_ref) == 0);
  	kmem_free(pag);
  }
@@ -192,9 +194,11 @@  xfs_free_perag(
  		ASSERT(pag);
  		ASSERT(atomic_read(&pag->pag_ref) == 0);
  
+#ifdef __KERNEL__
  		cancel_delayed_work_sync(&pag->pag_blockgc_work);
  		xfs_iunlink_destroy(pag);
  		xfs_buf_hash_destroy(pag);
+#endif	/* __KERNEL__ */
  
  		call_rcu(&pag->rcu_head, __xfs_free_perag);
  	}
@@ -246,6 +250,7 @@  xfs_initialize_perag(
  		spin_unlock(&mp->m_perag_lock);
  		radix_tree_preload_end();
  
+#ifdef __KERNEL__
  		/* Place kernel structure only init below this point. */
  		spin_lock_init(&pag->pag_ici_lock);
  		spin_lock_init(&pag->pagb_lock);
@@ -267,6 +272,7 @@  xfs_initialize_perag(
  		/* first new pag is fully initialized */
  		if (first_initialised == NULLAGNUMBER)
  			first_initialised = index;
+#endif	/* __KERNEL__ */
  	}
  
  	index = xfs_set_inode_alloc(mp, agcount);
@@ -277,10 +283,12 @@  xfs_initialize_perag(
  	mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
  	return 0;
  
+#ifdef __KERNEL__
  out_hash_destroy:
  	xfs_buf_hash_destroy(pag);
  out_remove_pag:
  	radix_tree_delete(&mp->m_perag_tree, index);
+#endif	/* __KERNEL__ */
  out_free_pag:
  	kmem_free(pag);
  out_unwind_new_pags:
diff --git a/libxfs/xfs_ag.h b/libxfs/xfs_ag.h
index 4c6f9045..dda1303e 100644
--- a/libxfs/xfs_ag.h
+++ b/libxfs/xfs_ag.h
@@ -64,6 +64,9 @@  struct xfs_perag {
  	/* Blocks reserved for the reverse mapping btree. */
  	struct xfs_ag_resv	pag_rmapbt_resv;
  
+	/* for rcu-safe freeing */
+	struct rcu_head	rcu_head;
+
  	/* -- kernel only structures below this line -- */
  
  	/*
@@ -75,6 +78,7 @@  struct xfs_perag {
  	spinlock_t	pag_state_lock;
  
  	spinlock_t	pagb_lock;	/* lock for pagb_tree */
+#ifdef __KERNEL__
  	struct rb_root	pagb_tree;	/* ordered tree of busy extents */
  	unsigned int	pagb_gen;	/* generation count for pagb_tree */
  	wait_queue_head_t pagb_wait;	/* woken when pagb_gen changes */
@@ -90,9 +94,6 @@  struct xfs_perag {
  	spinlock_t	pag_buf_lock;	/* lock for pag_buf_hash */
  	struct rhashtable pag_buf_hash;
  
-	/* for rcu-safe freeing */
-	struct rcu_head	rcu_head;
-
  	/* background prealloc block trimming */
  	struct delayed_work	pag_blockgc_work;
  
@@ -102,6 +103,7 @@  struct xfs_perag {
  	 * or have some other means to control concurrency.
  	 */
  	struct rhashtable	pagi_unlinked_hash;
+#endif	/* __KERNEL__ */
  };
  
  int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
diff --git a/libxfs/xfs_shared.h b/libxfs/xfs_shared.h
index bafee48c..25c4cab5 100644
--- a/libxfs/xfs_shared.h
+++ b/libxfs/xfs_shared.h
@@ -180,24 +180,4 @@  struct xfs_ino_geometry {
  
  };
  
-/* Faked up kernel bits */
-struct rb_root {
-};
-
-#define RB_ROOT 		(struct rb_root) { }
-
-typedef struct wait_queue_head {
-} wait_queue_head_t;
-
-#define init_waitqueue_head(wqh)	do { } while(0)
-
-struct rhashtable {
-};
-
-struct delayed_work {
-};
-
-#define INIT_DELAYED_WORK(work, func)	do { } while(0)
-#define cancel_delayed_work_sync(work)	do { } while(0)
-
  #endif /* __XFS_SHARED_H__ */