[PATCH] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[PATCH] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[Eric Sandeen]

Move kernel stubs out of libxfs/xfs_shared.h, which is kernel
libxfs code and should not have userspace shims in it.

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

diff --git a/include/libxfs.h b/include/libxfs.h
index 24424d0e..64b44af8 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -11,6 +11,7 @@
  #include "platform_defs.h"
  #include "xfs.h"
  
+#include "stubs.h"
  #include "list.h"
  #include "hlist.h"
  #include "cache.h"
diff --git a/include/stubs.h b/include/stubs.h
new file mode 100644
index 00000000..41eaa0c4
--- /dev/null
+++ b/include/stubs.h
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Stub out unimplemented and unneeded kernel structures etc
+ */
+#ifndef STUBS_H
+#define STUBS_H
+
+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
diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
index 15bae1ff..32271c66 100644
--- a/libxfs/libxfs_priv.h
+++ b/libxfs/libxfs_priv.h
@@ -41,6 +41,7 @@
  #include "platform_defs.h"
  #include "xfs.h"
  
+#include "stubs.h"
  #include "list.h"
  #include "hlist.h"
  #include "cache.h"
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__ */

Re: [PATCH] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[Darrick J. Wong]

On Wed, Nov 03, 2021 at 09:21:35PM -0500, Eric Sandeen wrote:
> Move kernel stubs out of libxfs/xfs_shared.h, which is kernel
> libxfs code and should not have userspace shims in it.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/include/libxfs.h b/include/libxfs.h
> index 24424d0e..64b44af8 100644
> --- a/include/libxfs.h
> +++ b/include/libxfs.h
> @@ -11,6 +11,7 @@
>  #include "platform_defs.h"
>  #include "xfs.h"
> +#include "stubs.h"
>  #include "list.h"
>  #include "hlist.h"
>  #include "cache.h"
> diff --git a/include/stubs.h b/include/stubs.h
> new file mode 100644
> index 00000000..41eaa0c4
> --- /dev/null
> +++ b/include/stubs.h
> @@ -0,0 +1,28 @@
> +// SPDX-License-Identifier: GPL-2.0

This needs a C-style (not C++-style) comment for SPDX compliance.

(I still don't get why the committee who came up with SPDX required C++
style comments for C code...)

> +

Needs a copyright statement too.

> +/*
> + * Stub out unimplemented and unneeded kernel structures etc
> + */
> +#ifndef STUBS_H
> +#define STUBS_H
> +
> +struct rb_root {
> +};
> +
> +#define RB_ROOT 		(struct rb_root) { }

Space after 'T' and before '('.

--D

> +
> +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
> diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
> index 15bae1ff..32271c66 100644
> --- a/libxfs/libxfs_priv.h
> +++ b/libxfs/libxfs_priv.h
> @@ -41,6 +41,7 @@
>  #include "platform_defs.h"
>  #include "xfs.h"
> +#include "stubs.h"
>  #include "list.h"
>  #include "hlist.h"
>  #include "cache.h"
> 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__ */
> 

Re: [PATCH] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[Eric Sandeen]

On 11/3/21 9:28 PM, Darrick J. Wong wrote:
> On Wed, Nov 03, 2021 at 09:21:35PM -0500, Eric Sandeen wrote:
>> Move kernel stubs out of libxfs/xfs_shared.h, which is kernel
>> libxfs code and should not have userspace shims in it.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> diff --git a/include/libxfs.h b/include/libxfs.h
>> index 24424d0e..64b44af8 100644
>> --- a/include/libxfs.h
>> +++ b/include/libxfs.h
>> @@ -11,6 +11,7 @@
>>   #include "platform_defs.h"
>>   #include "xfs.h"
>> +#include "stubs.h"
>>   #include "list.h"
>>   #include "hlist.h"
>>   #include "cache.h"
>> diff --git a/include/stubs.h b/include/stubs.h
>> new file mode 100644
>> index 00000000..41eaa0c4
>> --- /dev/null
>> +++ b/include/stubs.h
>> @@ -0,0 +1,28 @@
>> +// SPDX-License-Identifier: GPL-2.0
> 
> This needs a C-style (not C++-style) comment for SPDX compliance.
> 
> (I still don't get why the committee who came up with SPDX required C++
> style comments for C code...)
> 
>> +
> 
> Needs a copyright statement too.

well that's what I get for cargo-culting bitops.h.  :/

[PATCH V2] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[Eric Sandeen]

Move kernel stubs out of libxfs/xfs_shared.h, which is kernel
libxfs code and should not have userspace shims in it.

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

V2: fix spdx and copyright

diff --git a/include/libxfs.h b/include/libxfs.h
index 24424d0e..64b44af8 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -11,6 +11,7 @@
  #include "platform_defs.h"
  #include "xfs.h"
  
+#include "stubs.h"
  #include "list.h"
  #include "hlist.h"
  #include "cache.h"
diff --git a/include/stubs.h b/include/stubs.h
new file mode 100644
index 00000000..d80e8de0
--- /dev/null
+++ b/include/stubs.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021 Red Hat, Inc.
+ * All Rights Reserved.
+ */
+#ifndef STUBS_H
+#define STUBS_H
+
+/* Stub out unimplemented and unneeded kernel functions */
+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
diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
index 15bae1ff..32271c66 100644
--- a/libxfs/libxfs_priv.h
+++ b/libxfs/libxfs_priv.h
@@ -41,6 +41,7 @@
  #include "platform_defs.h"
  #include "xfs.h"
  
+#include "stubs.h"
  #include "list.h"
  #include "hlist.h"
  #include "cache.h"
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__ */

Re: [PATCH V2] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[Darrick J. Wong]

On Wed, Nov 03, 2021 at 09:59:57PM -0500, Eric Sandeen wrote:
> Move kernel stubs out of libxfs/xfs_shared.h, which is kernel
> libxfs code and should not have userspace shims in it.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> V2: fix spdx and copyright
> 
> diff --git a/include/libxfs.h b/include/libxfs.h
> index 24424d0e..64b44af8 100644
> --- a/include/libxfs.h
> +++ b/include/libxfs.h
> @@ -11,6 +11,7 @@
>  #include "platform_defs.h"
>  #include "xfs.h"
> +#include "stubs.h"
>  #include "list.h"
>  #include "hlist.h"
>  #include "cache.h"
> diff --git a/include/stubs.h b/include/stubs.h
> new file mode 100644
> index 00000000..d80e8de0
> --- /dev/null
> +++ b/include/stubs.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2021 Red Hat, Inc.
> + * All Rights Reserved.
> + */
> +#ifndef STUBS_H
> +#define STUBS_H
> +
> +/* Stub out unimplemented and unneeded kernel functions */
> +struct rb_root {
> +};
> +
> +#define RB_ROOT 		(struct rb_root) { }

Please to remove  ^ this unnecessary space.

> +
> +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

This probably ought to be '#endif /* STUBS_H */' just to keep it clear
which #ifdef it goes with.

With those two things fixed,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
> index 15bae1ff..32271c66 100644
> --- a/libxfs/libxfs_priv.h
> +++ b/libxfs/libxfs_priv.h
> @@ -41,6 +41,7 @@
>  #include "platform_defs.h"
>  #include "xfs.h"
> +#include "stubs.h"
>  #include "list.h"
>  #include "hlist.h"
>  #include "cache.h"
> 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__ */
> 

Re: [PATCH V2] xfsprogs: move stubbed-out kernel functions out of xfs_shared.h

[Eric Sandeen]

On 11/3/21 10:14 PM, Darrick J. Wong wrote:
> On Wed, Nov 03, 2021 at 09:59:57PM -0500, Eric Sandeen wrote:
>> Move kernel stubs out of libxfs/xfs_shared.h, which is kernel
>> libxfs code and should not have userspace shims in it.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> V2: fix spdx and copyright
>>
>> diff --git a/include/libxfs.h b/include/libxfs.h
>> index 24424d0e..64b44af8 100644
>> --- a/include/libxfs.h
>> +++ b/include/libxfs.h
>> @@ -11,6 +11,7 @@
>>   #include "platform_defs.h"
>>   #include "xfs.h"
>> +#include "stubs.h"
>>   #include "list.h"
>>   #include "hlist.h"
>>   #include "cache.h"
>> diff --git a/include/stubs.h b/include/stubs.h
>> new file mode 100644
>> index 00000000..d80e8de0
>> --- /dev/null
>> +++ b/include/stubs.h
>> @@ -0,0 +1,29 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) 2021 Red Hat, Inc.
>> + * All Rights Reserved.
>> + */
>> +#ifndef STUBS_H
>> +#define STUBS_H
>> +
>> +/* Stub out unimplemented and unneeded kernel functions */
>> +struct rb_root {
>> +};
>> +
>> +#define RB_ROOT 		(struct rb_root) { }
> 
> Please to remove  ^ this unnecessary space.
> 
>> +
>> +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
> 
> This probably ought to be '#endif /* STUBS_H */' just to keep it clear
> which #ifdef it goes with.

Yup I spotted and added that already. I'm so rusty.

> With those two things fixed,
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>

Thanks,
-Eric

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

[Eric Sandeen]

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);
  	}
@@ -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__ */

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

[Darrick J. Wong]

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__ */
> 

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

[Dave Chinner]

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.
-- 
Dave Chinner
david@fromorbit.com

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

[Eric Sandeen]

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__ */

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

[Dave Chinner]

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.
-- 
Dave Chinner
david@fromorbit.com