[PATCH v12 0/4] xfs: Remove wrappers for some semaphores

[PATCH v12 0/4] xfs: Remove wrappers for some semaphores

[Pavel Reichl]

Remove some wrappers that we have in XFS around the read-write semaphore
locks.

The goal of this cleanup is to remove mrlock_t structure and its mr*()
wrapper functions and replace it with native rw_semaphore type and its
native calls.

Changes in version 8:
* Patchset was rebased so it applies cleanly.
* The patch 'xfs: replace mrlock_t with rw_semaphores' contains change in
xfs_btree.c which transfers ownership of lock so lockdep won't assert
(This was reported by Darrick and proposed change fixes this issue).

Changes in version 9:
*Fixed white space in patch 'xfs: Refactor xfs_isilocked()'
*Updated code comments as suggested by djwong (thanks!) in patch: 'xfs: replace mrlock_t with rw_semaphores'

Changes in version 10:
* Fixed use-after-free in 'xfs: replace mrlock_t with rw_semaphores' (thanks Darrick)
* Moved part of refactor of xfs_isilocked() from patch 'xfs: Refactor xfs_isilocked()' to patch 'xfs: replace mrlock_t with rw_semaphores' - to fix compilation error
* Typo in comment in 'xfs: replace mrlock_t with rw_semaphores'

Changes in version 11:
* Dropped typedef xfs_node_t from xfs_isilocked in 'xfs: Refactor xfs_isilocked()'

Changes in version 12:

xfs: Refactor xfs_isilocked()
* Moved shifting lock_flags from xfs_ilocked() to __xfs_rwsem_ilocked()
* Changed comment in __xfs_rwsem_islocked()
* Removed the arg variable from __xfs_rwsem_islocked()
* Removed the extra parentheses around the lock 'defines'

xfs: replace mrlock_t with rw_semaphores
* Moved shifting lock_flags from xfs_ilocked() to __xfs_rwsem_ilocked()
* Updated comment in xfs_btree_split() before the rwsem_release()
* Added assert to  xfs_isilocked() for IOLOCK flags

Pavel Reichl (4):
  xfs: Refactor xfs_isilocked()
  xfs: clean up whitespace in xfs_isilocked() calls
  xfs: xfs_isilocked() can only check a single lock type
  xfs: replace mrlock_t with rw_semaphores

 fs/xfs/libxfs/xfs_bmap.c  |  8 ++--
 fs/xfs/libxfs/xfs_btree.c | 25 +++++++++++
 fs/xfs/mrlock.h           | 78 --------------------------------
 fs/xfs/xfs_file.c         |  3 +-
 fs/xfs/xfs_inode.c        | 95 +++++++++++++++++++++++++--------------
 fs/xfs/xfs_inode.h        | 25 +++++++----
 fs/xfs/xfs_iops.c         |  4 +-
 fs/xfs/xfs_linux.h        |  2 +-
 fs/xfs/xfs_qm.c           |  2 +-
 fs/xfs/xfs_super.c        |  6 +--
 10 files changed, 115 insertions(+), 133 deletions(-)
 delete mode 100644 fs/xfs/mrlock.h

-- 
2.26.2

[PATCH v12 1/4] xfs: Refactor xfs_isilocked()

[Pavel Reichl]

Refactor xfs_isilocked() to use newly introduced __xfs_rwsem_islocked().
__xfs_rwsem_islocked() is a helper function which encapsulates checking
state of rw_semaphores hold by inode.

Signed-off-by: Pavel Reichl <preichl@redhat.com>
Suggested-by: Dave Chinner <dchinner@redhat.com>
Suggested-by: Eric Sandeen <sandeen@redhat.com>
Suggested-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_inode.c | 39 +++++++++++++++++++++++++++++++--------
 fs/xfs/xfs_inode.h | 21 ++++++++++++++-------
 2 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index c06129cffba9..1fdf8c7eb990 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -345,9 +345,34 @@ xfs_ilock_demote(
 }
 
 #if defined(DEBUG) || defined(XFS_WARN)
-int
+static inline bool
+__xfs_rwsem_islocked(
+	struct rw_semaphore	*rwsem,
+	int			lock_flags,
+	int			shift)
+{
+	lock_flags >>= shift;
+
+	if (!debug_locks)
+		return rwsem_is_locked(rwsem);
+	/*
+	 * If the shared flag is not set, pass 0 to explicitly check for
+	 * exclusive access to the lock. If the shared flag is set, we typically
+	 * want to make sure the lock is at least held in shared mode
+	 * (i.e., shared | excl) but we don't necessarily care that it might
+	 * actually be held exclusive. Therefore, pass -1 to check whether the
+	 * lock is held in any mode rather than one of the explicit shared mode
+	 * values (1 or 2)."
+	 */
+	if (lock_flags & (1 << XFS_SHARED_LOCK_SHIFT)) {
+		return lockdep_is_held_type(rwsem, -1);
+	}
+	return lockdep_is_held_type(rwsem, 0);
+}
+
+bool
 xfs_isilocked(
-	xfs_inode_t		*ip,
+	struct xfs_inode	*ip,
 	uint			lock_flags)
 {
 	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
@@ -362,15 +387,13 @@ xfs_isilocked(
 		return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
 	}
 
-	if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
-		if (!(lock_flags & XFS_IOLOCK_SHARED))
-			return !debug_locks ||
-				lockdep_is_held_type(&VFS_I(ip)->i_rwsem, 0);
-		return rwsem_is_locked(&VFS_I(ip)->i_rwsem);
+	if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
+		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem, lock_flags,
+				XFS_IOLOCK_FLAG_SHIFT);
 	}
 
 	ASSERT(0);
-	return 0;
+	return false;
 }
 #endif
 
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index e9a8bb184d1f..9cecd6c9c90c 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -268,12 +268,19 @@ static inline void xfs_ifunlock(struct xfs_inode *ip)
  * Bit ranges:	1<<1  - 1<<16-1 -- iolock/ilock modes (bitfield)
  *		1<<16 - 1<<32-1 -- lockdep annotation (integers)
  */
-#define	XFS_IOLOCK_EXCL		(1<<0)
-#define	XFS_IOLOCK_SHARED	(1<<1)
-#define	XFS_ILOCK_EXCL		(1<<2)
-#define	XFS_ILOCK_SHARED	(1<<3)
-#define	XFS_MMAPLOCK_EXCL	(1<<4)
-#define	XFS_MMAPLOCK_SHARED	(1<<5)
+
+#define XFS_IOLOCK_FLAG_SHIFT	0
+#define XFS_ILOCK_FLAG_SHIFT	2
+#define XFS_MMAPLOCK_FLAG_SHIFT	4
+
+#define XFS_SHARED_LOCK_SHIFT	1
+
+#define XFS_IOLOCK_EXCL		(1 << XFS_IOLOCK_FLAG_SHIFT)
+#define XFS_IOLOCK_SHARED	(XFS_IOLOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
+#define XFS_ILOCK_EXCL		(1 << XFS_ILOCK_FLAG_SHIFT)
+#define XFS_ILOCK_SHARED	(XFS_ILOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
+#define XFS_MMAPLOCK_EXCL	(1 << XFS_MMAPLOCK_FLAG_SHIFT)
+#define XFS_MMAPLOCK_SHARED	(XFS_MMAPLOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
 
 #define XFS_LOCK_MASK		(XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED \
 				| XFS_ILOCK_EXCL | XFS_ILOCK_SHARED \
@@ -412,7 +419,7 @@ void		xfs_ilock(xfs_inode_t *, uint);
 int		xfs_ilock_nowait(xfs_inode_t *, uint);
 void		xfs_iunlock(xfs_inode_t *, uint);
 void		xfs_ilock_demote(xfs_inode_t *, uint);
-int		xfs_isilocked(xfs_inode_t *, uint);
+bool		xfs_isilocked(struct xfs_inode *, uint);
 uint		xfs_ilock_data_map_shared(struct xfs_inode *);
 uint		xfs_ilock_attr_map_shared(struct xfs_inode *);
 
-- 
2.26.2

Re: [PATCH v12 1/4] xfs: Refactor xfs_isilocked()

[Brian Foster]

On Fri, Oct 16, 2020 at 04:10:02AM +0200, Pavel Reichl wrote:
> Refactor xfs_isilocked() to use newly introduced __xfs_rwsem_islocked().
> __xfs_rwsem_islocked() is a helper function which encapsulates checking
> state of rw_semaphores hold by inode.
> 
> Signed-off-by: Pavel Reichl <preichl@redhat.com>
> Suggested-by: Dave Chinner <dchinner@redhat.com>
> Suggested-by: Eric Sandeen <sandeen@redhat.com>
> Suggested-by: Darrick J. Wong <darrick.wong@oracle.com>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_inode.c | 39 +++++++++++++++++++++++++++++++--------
>  fs/xfs/xfs_inode.h | 21 ++++++++++++++-------
>  2 files changed, 45 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index c06129cffba9..1fdf8c7eb990 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -345,9 +345,34 @@ xfs_ilock_demote(
>  }
>  
>  #if defined(DEBUG) || defined(XFS_WARN)
> -int
> +static inline bool
> +__xfs_rwsem_islocked(
> +	struct rw_semaphore	*rwsem,
> +	int			lock_flags,
> +	int			shift)
> +{
> +	lock_flags >>= shift;
> +
> +	if (!debug_locks)
> +		return rwsem_is_locked(rwsem);
> +	/*
> +	 * If the shared flag is not set, pass 0 to explicitly check for
> +	 * exclusive access to the lock. If the shared flag is set, we typically
> +	 * want to make sure the lock is at least held in shared mode
> +	 * (i.e., shared | excl) but we don't necessarily care that it might
> +	 * actually be held exclusive. Therefore, pass -1 to check whether the
> +	 * lock is held in any mode rather than one of the explicit shared mode
> +	 * values (1 or 2)."
> +	 */
> +	if (lock_flags & (1 << XFS_SHARED_LOCK_SHIFT)) {
> +		return lockdep_is_held_type(rwsem, -1);
> +	}

Nit: no need for braces here. Otherwise LGTM. Thanks for the tweaks.

Reviewed-by: Brian Foster <bfoster@redhat.com>

> +	return lockdep_is_held_type(rwsem, 0);
> +}
> +
> +bool
>  xfs_isilocked(
> -	xfs_inode_t		*ip,
> +	struct xfs_inode	*ip,
>  	uint			lock_flags)
>  {
>  	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
> @@ -362,15 +387,13 @@ xfs_isilocked(
>  		return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
>  	}
>  
> -	if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
> -		if (!(lock_flags & XFS_IOLOCK_SHARED))
> -			return !debug_locks ||
> -				lockdep_is_held_type(&VFS_I(ip)->i_rwsem, 0);
> -		return rwsem_is_locked(&VFS_I(ip)->i_rwsem);
> +	if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
> +		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem, lock_flags,
> +				XFS_IOLOCK_FLAG_SHIFT);
>  	}
>  
>  	ASSERT(0);
> -	return 0;
> +	return false;
>  }
>  #endif
>  
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index e9a8bb184d1f..9cecd6c9c90c 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -268,12 +268,19 @@ static inline void xfs_ifunlock(struct xfs_inode *ip)
>   * Bit ranges:	1<<1  - 1<<16-1 -- iolock/ilock modes (bitfield)
>   *		1<<16 - 1<<32-1 -- lockdep annotation (integers)
>   */
> -#define	XFS_IOLOCK_EXCL		(1<<0)
> -#define	XFS_IOLOCK_SHARED	(1<<1)
> -#define	XFS_ILOCK_EXCL		(1<<2)
> -#define	XFS_ILOCK_SHARED	(1<<3)
> -#define	XFS_MMAPLOCK_EXCL	(1<<4)
> -#define	XFS_MMAPLOCK_SHARED	(1<<5)
> +
> +#define XFS_IOLOCK_FLAG_SHIFT	0
> +#define XFS_ILOCK_FLAG_SHIFT	2
> +#define XFS_MMAPLOCK_FLAG_SHIFT	4
> +
> +#define XFS_SHARED_LOCK_SHIFT	1
> +
> +#define XFS_IOLOCK_EXCL		(1 << XFS_IOLOCK_FLAG_SHIFT)
> +#define XFS_IOLOCK_SHARED	(XFS_IOLOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
> +#define XFS_ILOCK_EXCL		(1 << XFS_ILOCK_FLAG_SHIFT)
> +#define XFS_ILOCK_SHARED	(XFS_ILOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
> +#define XFS_MMAPLOCK_EXCL	(1 << XFS_MMAPLOCK_FLAG_SHIFT)
> +#define XFS_MMAPLOCK_SHARED	(XFS_MMAPLOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
>  
>  #define XFS_LOCK_MASK		(XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED \
>  				| XFS_ILOCK_EXCL | XFS_ILOCK_SHARED \
> @@ -412,7 +419,7 @@ void		xfs_ilock(xfs_inode_t *, uint);
>  int		xfs_ilock_nowait(xfs_inode_t *, uint);
>  void		xfs_iunlock(xfs_inode_t *, uint);
>  void		xfs_ilock_demote(xfs_inode_t *, uint);
> -int		xfs_isilocked(xfs_inode_t *, uint);
> +bool		xfs_isilocked(struct xfs_inode *, uint);
>  uint		xfs_ilock_data_map_shared(struct xfs_inode *);
>  uint		xfs_ilock_attr_map_shared(struct xfs_inode *);
>  
> -- 
> 2.26.2
> 

[PATCH v12 2/4] xfs: clean up whitespace in xfs_isilocked() calls

[Pavel Reichl]

Make whitespace follow the same pattern in all xfs_isilocked() calls.

Signed-off-by: Pavel Reichl <preichl@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_bmap.c | 2 +-
 fs/xfs/xfs_file.c        | 3 ++-
 fs/xfs/xfs_inode.c       | 4 ++--
 fs/xfs/xfs_qm.c          | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 1b0a01b06a05..ced3b996cd8a 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3883,7 +3883,7 @@ xfs_bmapi_read(
 
 	ASSERT(*nmap >= 1);
 	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK | XFS_BMAPI_ENTIRE)));
-	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
 
 	if (WARN_ON_ONCE(!ifp))
 		return -EFSCORRUPTED;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index a29f78a663ca..c8b1d4e4199a 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -763,7 +763,8 @@ xfs_break_layouts(
 	bool			retry;
 	int			error;
 
-	ASSERT(xfs_isilocked(XFS_I(inode), XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
+	ASSERT(xfs_isilocked(XFS_I(inode),
+			XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
 
 	do {
 		retry = false;
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 1fdf8c7eb990..085927700530 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2772,7 +2772,7 @@ static void
 xfs_iunpin(
 	struct xfs_inode	*ip)
 {
-	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
 
 	trace_xfs_inode_unpin_nowait(ip, _RET_IP_);
 
@@ -3465,7 +3465,7 @@ xfs_iflush(
 	struct xfs_mount	*mp = ip->i_mount;
 	int			error;
 
-	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
 	ASSERT(xfs_isiflocked(ip));
 	ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE ||
 	       ip->i_df.if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK));
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index be67570badf8..57bfa5266c47 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1803,7 +1803,7 @@ xfs_qm_vop_chown_reserve(
 	int			error;
 
 
-	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
 	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
 
 	delblks = ip->i_delayed_blks;
-- 
2.26.2

[PATCH v12 3/4] xfs: xfs_isilocked() can only check a single lock type

[Pavel Reichl]

In its current form, xfs_isilocked() is only able to test one lock type
at a time - ilock, iolock, or mmap lock, but combinations are not
properly handled. The intent here is to check that both XFS_IOLOCK_EXCL
and XFS_ILOCK_EXCL are held, so test them each separately.

The commit ecfea3f0c8c6 ("xfs: split xfs_bmap_shift_extents") ORed the
flags together which was an error, so this patch reverts that part of
the change and check the locks independently.

Fixes: ecfea3f0c8c6 ("xfs: split xfs_bmap_shift_extents")

Suggested-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Pavel Reichl <preichl@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_bmap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index ced3b996cd8a..ff5cc8a5d476 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5787,7 +5787,8 @@ xfs_bmap_collapse_extents(
 	if (XFS_FORCED_SHUTDOWN(mp))
 		return -EIO;
 
-	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
 	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
 		error = xfs_iread_extents(tp, ip, whichfork);
@@ -5904,7 +5905,8 @@ xfs_bmap_insert_extents(
 	if (XFS_FORCED_SHUTDOWN(mp))
 		return -EIO;
 
-	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
 	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
 		error = xfs_iread_extents(tp, ip, whichfork);
-- 
2.26.2

[PATCH v12 4/4] xfs: replace mrlock_t with rw_semaphores

[Pavel Reichl]

Remove mrlock_t as it does not provide any extra value over
rw_semaphores. Make i_lock and i_mmaplock native rw_semaphores and
replace mr*() functions with native rwsem calls.

Release the lock in xfs_btree_split() just before the work-queue
executing xfs_btree_split_worker() is scheduled and make
xfs_btree_split_worker() to acquire the lock as a first thing and
release it just before returning from the function. This it done so the
ownership of the lock is transfered between kernel threads and thus
lockdep won't complain about lock being held by a different kernel
thread.

Signed-off-by: Pavel Reichl <preichl@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_btree.c | 25 +++++++++++++
 fs/xfs/mrlock.h           | 78 ---------------------------------------
 fs/xfs/xfs_inode.c        | 52 ++++++++++++++------------
 fs/xfs/xfs_inode.h        |  4 +-
 fs/xfs/xfs_iops.c         |  4 +-
 fs/xfs/xfs_linux.h        |  2 +-
 fs/xfs/xfs_super.c        |  6 +--
 7 files changed, 60 insertions(+), 111 deletions(-)
 delete mode 100644 fs/xfs/mrlock.h

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 2d25bab68764..5ec2098c271c 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2816,6 +2816,12 @@ xfs_btree_split_worker(
 	unsigned long		pflags;
 	unsigned long		new_pflags = PF_MEMALLOC_NOFS;
 
+	/*
+	 * Update lockdep's lock ownership information to point to
+	 * this thread as the thread that scheduled this worker is waiting
+	 * for its completion.
+	 */
+	rwsem_acquire(&args->cur->bc_ino.ip->i_lock.dep_map, 0, 0, _RET_IP_);
 	/*
 	 * we are in a transaction context here, but may also be doing work
 	 * in kswapd context, and hence we may need to inherit that state
@@ -2829,6 +2835,12 @@ xfs_btree_split_worker(
 
 	args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
 					 args->key, args->curp, args->stat);
+	/*
+	 * Update lockdep's lock ownership information to reflect that we will
+	 * be transferring the ilock from this worker back to the scheduling
+	 * thread.
+	 */
+	rwsem_release(&args->cur->bc_ino.ip->i_lock.dep_map, _THIS_IP_);
 	complete(args->done);
 
 	current_restore_flags_nested(&pflags, new_pflags);
@@ -2863,8 +2875,21 @@ xfs_btree_split(
 	args.done = &done;
 	args.kswapd = current_is_kswapd();
 	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
+	/*
+	 * Update lockdep's ownership information to reflect transfer of the
+	 * ilock from the current task to the worker. Otherwise assertions that
+	 * the lock is held (such as when logging the inode) might fail due to
+	 * incorrect task owner state.
+	 */
+	rwsem_release(&cur->bc_ino.ip->i_lock.dep_map, _THIS_IP_);
 	queue_work(xfs_alloc_wq, &args.work);
 	wait_for_completion(&done);
+	/*
+	 * Update lockdep's lock ownership information to point to
+	 * this thread as the lock owner now that the worker item is
+	 * done.
+	 */
+	rwsem_acquire(&cur->bc_ino.ip->i_lock.dep_map, 0, 0, _RET_IP_);
 	destroy_work_on_stack(&args.work);
 	return args.result;
 }
diff --git a/fs/xfs/mrlock.h b/fs/xfs/mrlock.h
deleted file mode 100644
index 79155eec341b..000000000000
--- a/fs/xfs/mrlock.h
+++ /dev/null
@@ -1,78 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (c) 2000-2006 Silicon Graphics, Inc.
- * All Rights Reserved.
- */
-#ifndef __XFS_SUPPORT_MRLOCK_H__
-#define __XFS_SUPPORT_MRLOCK_H__
-
-#include <linux/rwsem.h>
-
-typedef struct {
-	struct rw_semaphore	mr_lock;
-#if defined(DEBUG) || defined(XFS_WARN)
-	int			mr_writer;
-#endif
-} mrlock_t;
-
-#if defined(DEBUG) || defined(XFS_WARN)
-#define mrinit(mrp, name)	\
-	do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
-#else
-#define mrinit(mrp, name)	\
-	do { init_rwsem(&(mrp)->mr_lock); } while (0)
-#endif
-
-#define mrlock_init(mrp, t,n,s)	mrinit(mrp, n)
-#define mrfree(mrp)		do { } while (0)
-
-static inline void mraccess_nested(mrlock_t *mrp, int subclass)
-{
-	down_read_nested(&mrp->mr_lock, subclass);
-}
-
-static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
-{
-	down_write_nested(&mrp->mr_lock, subclass);
-#if defined(DEBUG) || defined(XFS_WARN)
-	mrp->mr_writer = 1;
-#endif
-}
-
-static inline int mrtryaccess(mrlock_t *mrp)
-{
-	return down_read_trylock(&mrp->mr_lock);
-}
-
-static inline int mrtryupdate(mrlock_t *mrp)
-{
-	if (!down_write_trylock(&mrp->mr_lock))
-		return 0;
-#if defined(DEBUG) || defined(XFS_WARN)
-	mrp->mr_writer = 1;
-#endif
-	return 1;
-}
-
-static inline void mrunlock_excl(mrlock_t *mrp)
-{
-#if defined(DEBUG) || defined(XFS_WARN)
-	mrp->mr_writer = 0;
-#endif
-	up_write(&mrp->mr_lock);
-}
-
-static inline void mrunlock_shared(mrlock_t *mrp)
-{
-	up_read(&mrp->mr_lock);
-}
-
-static inline void mrdemote(mrlock_t *mrp)
-{
-#if defined(DEBUG) || defined(XFS_WARN)
-	mrp->mr_writer = 0;
-#endif
-	downgrade_write(&mrp->mr_lock);
-}
-
-#endif /* __XFS_SUPPORT_MRLOCK_H__ */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 085927700530..f47202c487e0 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -191,14 +191,15 @@ xfs_ilock(
 	}
 
 	if (lock_flags & XFS_MMAPLOCK_EXCL)
-		mrupdate_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
+		down_write_nested(&ip->i_mmaplock,
+				XFS_MMAPLOCK_DEP(lock_flags));
 	else if (lock_flags & XFS_MMAPLOCK_SHARED)
-		mraccess_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
+		down_read_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
 
 	if (lock_flags & XFS_ILOCK_EXCL)
-		mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
+		down_write_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
 	else if (lock_flags & XFS_ILOCK_SHARED)
-		mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
+		down_read_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
 }
 
 /*
@@ -242,27 +243,27 @@ xfs_ilock_nowait(
 	}
 
 	if (lock_flags & XFS_MMAPLOCK_EXCL) {
-		if (!mrtryupdate(&ip->i_mmaplock))
+		if (!down_write_trylock(&ip->i_mmaplock))
 			goto out_undo_iolock;
 	} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
-		if (!mrtryaccess(&ip->i_mmaplock))
+		if (!down_read_trylock(&ip->i_mmaplock))
 			goto out_undo_iolock;
 	}
 
 	if (lock_flags & XFS_ILOCK_EXCL) {
-		if (!mrtryupdate(&ip->i_lock))
+		if (!down_write_trylock(&ip->i_lock))
 			goto out_undo_mmaplock;
 	} else if (lock_flags & XFS_ILOCK_SHARED) {
-		if (!mrtryaccess(&ip->i_lock))
+		if (!down_read_trylock(&ip->i_lock))
 			goto out_undo_mmaplock;
 	}
 	return 1;
 
 out_undo_mmaplock:
 	if (lock_flags & XFS_MMAPLOCK_EXCL)
-		mrunlock_excl(&ip->i_mmaplock);
+		up_write(&ip->i_mmaplock);
 	else if (lock_flags & XFS_MMAPLOCK_SHARED)
-		mrunlock_shared(&ip->i_mmaplock);
+		up_read(&ip->i_mmaplock);
 out_undo_iolock:
 	if (lock_flags & XFS_IOLOCK_EXCL)
 		up_write(&VFS_I(ip)->i_rwsem);
@@ -309,14 +310,14 @@ xfs_iunlock(
 		up_read(&VFS_I(ip)->i_rwsem);
 
 	if (lock_flags & XFS_MMAPLOCK_EXCL)
-		mrunlock_excl(&ip->i_mmaplock);
+		up_write(&ip->i_mmaplock);
 	else if (lock_flags & XFS_MMAPLOCK_SHARED)
-		mrunlock_shared(&ip->i_mmaplock);
+		up_read(&ip->i_mmaplock);
 
 	if (lock_flags & XFS_ILOCK_EXCL)
-		mrunlock_excl(&ip->i_lock);
+		up_write(&ip->i_lock);
 	else if (lock_flags & XFS_ILOCK_SHARED)
-		mrunlock_shared(&ip->i_lock);
+		up_read(&ip->i_lock);
 
 	trace_xfs_iunlock(ip, lock_flags, _RET_IP_);
 }
@@ -335,9 +336,9 @@ xfs_ilock_demote(
 		~(XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
 
 	if (lock_flags & XFS_ILOCK_EXCL)
-		mrdemote(&ip->i_lock);
+		downgrade_write(&ip->i_lock);
 	if (lock_flags & XFS_MMAPLOCK_EXCL)
-		mrdemote(&ip->i_mmaplock);
+		downgrade_write(&ip->i_mmaplock);
 	if (lock_flags & XFS_IOLOCK_EXCL)
 		downgrade_write(&VFS_I(ip)->i_rwsem);
 
@@ -375,19 +376,22 @@ xfs_isilocked(
 	struct xfs_inode	*ip,
 	uint			lock_flags)
 {
-	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
-		if (!(lock_flags & XFS_ILOCK_SHARED))
-			return !!ip->i_lock.mr_writer;
-		return rwsem_is_locked(&ip->i_lock.mr_lock);
+	if (lock_flags & (XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)) {
+		ASSERT(!(lock_flags & ~(XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)));
+		return __xfs_rwsem_islocked(&ip->i_lock, lock_flags,
+				XFS_ILOCK_FLAG_SHIFT);
 	}
 
-	if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
-		if (!(lock_flags & XFS_MMAPLOCK_SHARED))
-			return !!ip->i_mmaplock.mr_writer;
-		return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
+	if (lock_flags & (XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED)) {
+		ASSERT(!(lock_flags &
+			~(XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED)));
+		return __xfs_rwsem_islocked(&ip->i_mmaplock, lock_flags,
+				XFS_MMAPLOCK_FLAG_SHIFT);
 	}
 
 	if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
+		ASSERT(!(lock_flags &
+			~(XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)));
 		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem, lock_flags,
 				XFS_IOLOCK_FLAG_SHIFT);
 	}
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 9cecd6c9c90c..413998972b35 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -39,8 +39,8 @@ typedef struct xfs_inode {
 
 	/* Transaction and locking information. */
 	struct xfs_inode_log_item *i_itemp;	/* logging information */
-	mrlock_t		i_lock;		/* inode lock */
-	mrlock_t		i_mmaplock;	/* inode mmap IO lock */
+	struct rw_semaphore	i_lock;		/* inode lock */
+	struct rw_semaphore	i_mmaplock;	/* inode mmap IO lock */
 	atomic_t		i_pincount;	/* inode pin count */
 
 	/*
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 80a13c8561d8..66cca3e599c7 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1336,9 +1336,9 @@ xfs_setup_inode(
 		 */
 		lockdep_set_class(&inode->i_rwsem,
 				  &inode->i_sb->s_type->i_mutex_dir_key);
-		lockdep_set_class(&ip->i_lock.mr_lock, &xfs_dir_ilock_class);
+		lockdep_set_class(&ip->i_lock, &xfs_dir_ilock_class);
 	} else {
-		lockdep_set_class(&ip->i_lock.mr_lock, &xfs_nondir_ilock_class);
+		lockdep_set_class(&ip->i_lock, &xfs_nondir_ilock_class);
 	}
 
 	/*
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index ab737fed7b12..ba37217f86d2 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -22,7 +22,6 @@ typedef __u32			xfs_nlink_t;
 #include "xfs_types.h"
 
 #include "kmem.h"
-#include "mrlock.h"
 
 #include <linux/semaphore.h>
 #include <linux/mm.h>
@@ -61,6 +60,7 @@ typedef __u32			xfs_nlink_t;
 #include <linux/ratelimit.h>
 #include <linux/rhashtable.h>
 #include <linux/xattr.h>
+#include <linux/rwsem.h>
 
 #include <asm/page.h>
 #include <asm/div64.h>
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 71ac6c1cdc36..00be9cfa29fa 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -708,10 +708,8 @@ xfs_fs_inode_init_once(
 	atomic_set(&ip->i_pincount, 0);
 	spin_lock_init(&ip->i_flags_lock);
 
-	mrlock_init(&ip->i_mmaplock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
-		     "xfsino", ip->i_ino);
-	mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
-		     "xfsino", ip->i_ino);
+	init_rwsem(&ip->i_mmaplock);
+	init_rwsem(&ip->i_lock);
 }
 
 /*
-- 
2.26.2

Re: [PATCH v12 4/4] xfs: replace mrlock_t with rw_semaphores

[Brian Foster]

On Fri, Oct 16, 2020 at 04:10:05AM +0200, Pavel Reichl wrote:
> Remove mrlock_t as it does not provide any extra value over
> rw_semaphores. Make i_lock and i_mmaplock native rw_semaphores and
> replace mr*() functions with native rwsem calls.
> 
> Release the lock in xfs_btree_split() just before the work-queue
> executing xfs_btree_split_worker() is scheduled and make
> xfs_btree_split_worker() to acquire the lock as a first thing and
> release it just before returning from the function. This it done so the
> ownership of the lock is transfered between kernel threads and thus
> lockdep won't complain about lock being held by a different kernel
> thread.
> 
> Signed-off-by: Pavel Reichl <preichl@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/libxfs/xfs_btree.c | 25 +++++++++++++
>  fs/xfs/mrlock.h           | 78 ---------------------------------------
>  fs/xfs/xfs_inode.c        | 52 ++++++++++++++------------
>  fs/xfs/xfs_inode.h        |  4 +-
>  fs/xfs/xfs_iops.c         |  4 +-
>  fs/xfs/xfs_linux.h        |  2 +-
>  fs/xfs/xfs_super.c        |  6 +--
>  7 files changed, 60 insertions(+), 111 deletions(-)
>  delete mode 100644 fs/xfs/mrlock.h
> 
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index 2d25bab68764..5ec2098c271c 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
...
> @@ -2863,8 +2875,21 @@ xfs_btree_split(
>  	args.done = &done;
>  	args.kswapd = current_is_kswapd();
>  	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
> +	/*
> +	 * Update lockdep's ownership information to reflect transfer of the
> +	 * ilock from the current task to the worker. Otherwise assertions that
> +	 * the lock is held (such as when logging the inode) might fail due to
> +	 * incorrect task owner state.
> +	 */
> +	rwsem_release(&cur->bc_ino.ip->i_lock.dep_map, _THIS_IP_);

IMO this one comment is sufficient to document what's happening and why,
and we could drop the remaining multi-line comments associated with each
lockdep state update call. Alternatively, the others could be reduced to
single line comments along the lines of "transfer lock to workqueue
task," etc. That's just my .02 though.

Also, no need to respin this or patch 1 based on my comments alone. I'm
just pointing out a couple nits that the maintainer can choose to tweak
or not at his discretion:

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  	queue_work(xfs_alloc_wq, &args.work);
>  	wait_for_completion(&done);
> +	/*
> +	 * Update lockdep's lock ownership information to point to
> +	 * this thread as the lock owner now that the worker item is
> +	 * done.
> +	 */
> +	rwsem_acquire(&cur->bc_ino.ip->i_lock.dep_map, 0, 0, _RET_IP_);
>  	destroy_work_on_stack(&args.work);
>  	return args.result;
>  }
> diff --git a/fs/xfs/mrlock.h b/fs/xfs/mrlock.h
> deleted file mode 100644
> index 79155eec341b..000000000000
> --- a/fs/xfs/mrlock.h
> +++ /dev/null
> @@ -1,78 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * Copyright (c) 2000-2006 Silicon Graphics, Inc.
> - * All Rights Reserved.
> - */
> -#ifndef __XFS_SUPPORT_MRLOCK_H__
> -#define __XFS_SUPPORT_MRLOCK_H__
> -
> -#include <linux/rwsem.h>
> -
> -typedef struct {
> -	struct rw_semaphore	mr_lock;
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	int			mr_writer;
> -#endif
> -} mrlock_t;
> -
> -#if defined(DEBUG) || defined(XFS_WARN)
> -#define mrinit(mrp, name)	\
> -	do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
> -#else
> -#define mrinit(mrp, name)	\
> -	do { init_rwsem(&(mrp)->mr_lock); } while (0)
> -#endif
> -
> -#define mrlock_init(mrp, t,n,s)	mrinit(mrp, n)
> -#define mrfree(mrp)		do { } while (0)
> -
> -static inline void mraccess_nested(mrlock_t *mrp, int subclass)
> -{
> -	down_read_nested(&mrp->mr_lock, subclass);
> -}
> -
> -static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
> -{
> -	down_write_nested(&mrp->mr_lock, subclass);
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 1;
> -#endif
> -}
> -
> -static inline int mrtryaccess(mrlock_t *mrp)
> -{
> -	return down_read_trylock(&mrp->mr_lock);
> -}
> -
> -static inline int mrtryupdate(mrlock_t *mrp)
> -{
> -	if (!down_write_trylock(&mrp->mr_lock))
> -		return 0;
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 1;
> -#endif
> -	return 1;
> -}
> -
> -static inline void mrunlock_excl(mrlock_t *mrp)
> -{
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 0;
> -#endif
> -	up_write(&mrp->mr_lock);
> -}
> -
> -static inline void mrunlock_shared(mrlock_t *mrp)
> -{
> -	up_read(&mrp->mr_lock);
> -}
> -
> -static inline void mrdemote(mrlock_t *mrp)
> -{
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 0;
> -#endif
> -	downgrade_write(&mrp->mr_lock);
> -}
> -
> -#endif /* __XFS_SUPPORT_MRLOCK_H__ */
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 085927700530..f47202c487e0 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -191,14 +191,15 @@ xfs_ilock(
>  	}
>  
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrupdate_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
> +		down_write_nested(&ip->i_mmaplock,
> +				XFS_MMAPLOCK_DEP(lock_flags));
>  	else if (lock_flags & XFS_MMAPLOCK_SHARED)
> -		mraccess_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
> +		down_read_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
>  
>  	if (lock_flags & XFS_ILOCK_EXCL)
> -		mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
> +		down_write_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
>  	else if (lock_flags & XFS_ILOCK_SHARED)
> -		mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
> +		down_read_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
>  }
>  
>  /*
> @@ -242,27 +243,27 @@ xfs_ilock_nowait(
>  	}
>  
>  	if (lock_flags & XFS_MMAPLOCK_EXCL) {
> -		if (!mrtryupdate(&ip->i_mmaplock))
> +		if (!down_write_trylock(&ip->i_mmaplock))
>  			goto out_undo_iolock;
>  	} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
> -		if (!mrtryaccess(&ip->i_mmaplock))
> +		if (!down_read_trylock(&ip->i_mmaplock))
>  			goto out_undo_iolock;
>  	}
>  
>  	if (lock_flags & XFS_ILOCK_EXCL) {
> -		if (!mrtryupdate(&ip->i_lock))
> +		if (!down_write_trylock(&ip->i_lock))
>  			goto out_undo_mmaplock;
>  	} else if (lock_flags & XFS_ILOCK_SHARED) {
> -		if (!mrtryaccess(&ip->i_lock))
> +		if (!down_read_trylock(&ip->i_lock))
>  			goto out_undo_mmaplock;
>  	}
>  	return 1;
>  
>  out_undo_mmaplock:
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrunlock_excl(&ip->i_mmaplock);
> +		up_write(&ip->i_mmaplock);
>  	else if (lock_flags & XFS_MMAPLOCK_SHARED)
> -		mrunlock_shared(&ip->i_mmaplock);
> +		up_read(&ip->i_mmaplock);
>  out_undo_iolock:
>  	if (lock_flags & XFS_IOLOCK_EXCL)
>  		up_write(&VFS_I(ip)->i_rwsem);
> @@ -309,14 +310,14 @@ xfs_iunlock(
>  		up_read(&VFS_I(ip)->i_rwsem);
>  
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrunlock_excl(&ip->i_mmaplock);
> +		up_write(&ip->i_mmaplock);
>  	else if (lock_flags & XFS_MMAPLOCK_SHARED)
> -		mrunlock_shared(&ip->i_mmaplock);
> +		up_read(&ip->i_mmaplock);
>  
>  	if (lock_flags & XFS_ILOCK_EXCL)
> -		mrunlock_excl(&ip->i_lock);
> +		up_write(&ip->i_lock);
>  	else if (lock_flags & XFS_ILOCK_SHARED)
> -		mrunlock_shared(&ip->i_lock);
> +		up_read(&ip->i_lock);
>  
>  	trace_xfs_iunlock(ip, lock_flags, _RET_IP_);
>  }
> @@ -335,9 +336,9 @@ xfs_ilock_demote(
>  		~(XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
>  
>  	if (lock_flags & XFS_ILOCK_EXCL)
> -		mrdemote(&ip->i_lock);
> +		downgrade_write(&ip->i_lock);
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrdemote(&ip->i_mmaplock);
> +		downgrade_write(&ip->i_mmaplock);
>  	if (lock_flags & XFS_IOLOCK_EXCL)
>  		downgrade_write(&VFS_I(ip)->i_rwsem);
>  
> @@ -375,19 +376,22 @@ xfs_isilocked(
>  	struct xfs_inode	*ip,
>  	uint			lock_flags)
>  {
> -	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
> -		if (!(lock_flags & XFS_ILOCK_SHARED))
> -			return !!ip->i_lock.mr_writer;
> -		return rwsem_is_locked(&ip->i_lock.mr_lock);
> +	if (lock_flags & (XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)) {
> +		ASSERT(!(lock_flags & ~(XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)));
> +		return __xfs_rwsem_islocked(&ip->i_lock, lock_flags,
> +				XFS_ILOCK_FLAG_SHIFT);
>  	}
>  
> -	if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
> -		if (!(lock_flags & XFS_MMAPLOCK_SHARED))
> -			return !!ip->i_mmaplock.mr_writer;
> -		return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
> +	if (lock_flags & (XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED)) {
> +		ASSERT(!(lock_flags &
> +			~(XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED)));
> +		return __xfs_rwsem_islocked(&ip->i_mmaplock, lock_flags,
> +				XFS_MMAPLOCK_FLAG_SHIFT);
>  	}
>  
>  	if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
> +		ASSERT(!(lock_flags &
> +			~(XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)));
>  		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem, lock_flags,
>  				XFS_IOLOCK_FLAG_SHIFT);
>  	}
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 9cecd6c9c90c..413998972b35 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -39,8 +39,8 @@ typedef struct xfs_inode {
>  
>  	/* Transaction and locking information. */
>  	struct xfs_inode_log_item *i_itemp;	/* logging information */
> -	mrlock_t		i_lock;		/* inode lock */
> -	mrlock_t		i_mmaplock;	/* inode mmap IO lock */
> +	struct rw_semaphore	i_lock;		/* inode lock */
> +	struct rw_semaphore	i_mmaplock;	/* inode mmap IO lock */
>  	atomic_t		i_pincount;	/* inode pin count */
>  
>  	/*
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 80a13c8561d8..66cca3e599c7 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -1336,9 +1336,9 @@ xfs_setup_inode(
>  		 */
>  		lockdep_set_class(&inode->i_rwsem,
>  				  &inode->i_sb->s_type->i_mutex_dir_key);
> -		lockdep_set_class(&ip->i_lock.mr_lock, &xfs_dir_ilock_class);
> +		lockdep_set_class(&ip->i_lock, &xfs_dir_ilock_class);
>  	} else {
> -		lockdep_set_class(&ip->i_lock.mr_lock, &xfs_nondir_ilock_class);
> +		lockdep_set_class(&ip->i_lock, &xfs_nondir_ilock_class);
>  	}
>  
>  	/*
> diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
> index ab737fed7b12..ba37217f86d2 100644
> --- a/fs/xfs/xfs_linux.h
> +++ b/fs/xfs/xfs_linux.h
> @@ -22,7 +22,6 @@ typedef __u32			xfs_nlink_t;
>  #include "xfs_types.h"
>  
>  #include "kmem.h"
> -#include "mrlock.h"
>  
>  #include <linux/semaphore.h>
>  #include <linux/mm.h>
> @@ -61,6 +60,7 @@ typedef __u32			xfs_nlink_t;
>  #include <linux/ratelimit.h>
>  #include <linux/rhashtable.h>
>  #include <linux/xattr.h>
> +#include <linux/rwsem.h>
>  
>  #include <asm/page.h>
>  #include <asm/div64.h>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 71ac6c1cdc36..00be9cfa29fa 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -708,10 +708,8 @@ xfs_fs_inode_init_once(
>  	atomic_set(&ip->i_pincount, 0);
>  	spin_lock_init(&ip->i_flags_lock);
>  
> -	mrlock_init(&ip->i_mmaplock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
> -		     "xfsino", ip->i_ino);
> -	mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
> -		     "xfsino", ip->i_ino);
> +	init_rwsem(&ip->i_mmaplock);
> +	init_rwsem(&ip->i_lock);
>  }
>  
>  /*
> -- 
> 2.26.2
> 

Re: [PATCH v12 4/4] xfs: replace mrlock_t with rw_semaphores

[Darrick J. Wong]

On Fri, Oct 16, 2020 at 04:10:05AM +0200, Pavel Reichl wrote:
> Remove mrlock_t as it does not provide any extra value over
> rw_semaphores. Make i_lock and i_mmaplock native rw_semaphores and
> replace mr*() functions with native rwsem calls.
> 
> Release the lock in xfs_btree_split() just before the work-queue
> executing xfs_btree_split_worker() is scheduled and make
> xfs_btree_split_worker() to acquire the lock as a first thing and
> release it just before returning from the function. This it done so the
> ownership of the lock is transfered between kernel threads and thus
> lockdep won't complain about lock being held by a different kernel
> thread.
> 
> Signed-off-by: Pavel Reichl <preichl@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Looks ok to me.  Would you mind rebasing this against 5.10-rc1 so I can
start testing a work branch with all the accumulated 5.11 stuff?

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/libxfs/xfs_btree.c | 25 +++++++++++++
>  fs/xfs/mrlock.h           | 78 ---------------------------------------
>  fs/xfs/xfs_inode.c        | 52 ++++++++++++++------------
>  fs/xfs/xfs_inode.h        |  4 +-
>  fs/xfs/xfs_iops.c         |  4 +-
>  fs/xfs/xfs_linux.h        |  2 +-
>  fs/xfs/xfs_super.c        |  6 +--
>  7 files changed, 60 insertions(+), 111 deletions(-)
>  delete mode 100644 fs/xfs/mrlock.h
> 
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index 2d25bab68764..5ec2098c271c 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -2816,6 +2816,12 @@ xfs_btree_split_worker(
>  	unsigned long		pflags;
>  	unsigned long		new_pflags = PF_MEMALLOC_NOFS;
>  
> +	/*
> +	 * Update lockdep's lock ownership information to point to
> +	 * this thread as the thread that scheduled this worker is waiting
> +	 * for its completion.
> +	 */
> +	rwsem_acquire(&args->cur->bc_ino.ip->i_lock.dep_map, 0, 0, _RET_IP_);
>  	/*
>  	 * we are in a transaction context here, but may also be doing work
>  	 * in kswapd context, and hence we may need to inherit that state
> @@ -2829,6 +2835,12 @@ xfs_btree_split_worker(
>  
>  	args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
>  					 args->key, args->curp, args->stat);
> +	/*
> +	 * Update lockdep's lock ownership information to reflect that we will
> +	 * be transferring the ilock from this worker back to the scheduling
> +	 * thread.
> +	 */
> +	rwsem_release(&args->cur->bc_ino.ip->i_lock.dep_map, _THIS_IP_);
>  	complete(args->done);
>  
>  	current_restore_flags_nested(&pflags, new_pflags);
> @@ -2863,8 +2875,21 @@ xfs_btree_split(
>  	args.done = &done;
>  	args.kswapd = current_is_kswapd();
>  	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
> +	/*
> +	 * Update lockdep's ownership information to reflect transfer of the
> +	 * ilock from the current task to the worker. Otherwise assertions that
> +	 * the lock is held (such as when logging the inode) might fail due to
> +	 * incorrect task owner state.
> +	 */
> +	rwsem_release(&cur->bc_ino.ip->i_lock.dep_map, _THIS_IP_);
>  	queue_work(xfs_alloc_wq, &args.work);
>  	wait_for_completion(&done);
> +	/*
> +	 * Update lockdep's lock ownership information to point to
> +	 * this thread as the lock owner now that the worker item is
> +	 * done.
> +	 */
> +	rwsem_acquire(&cur->bc_ino.ip->i_lock.dep_map, 0, 0, _RET_IP_);
>  	destroy_work_on_stack(&args.work);
>  	return args.result;
>  }
> diff --git a/fs/xfs/mrlock.h b/fs/xfs/mrlock.h
> deleted file mode 100644
> index 79155eec341b..000000000000
> --- a/fs/xfs/mrlock.h
> +++ /dev/null
> @@ -1,78 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * Copyright (c) 2000-2006 Silicon Graphics, Inc.
> - * All Rights Reserved.
> - */
> -#ifndef __XFS_SUPPORT_MRLOCK_H__
> -#define __XFS_SUPPORT_MRLOCK_H__
> -
> -#include <linux/rwsem.h>
> -
> -typedef struct {
> -	struct rw_semaphore	mr_lock;
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	int			mr_writer;
> -#endif
> -} mrlock_t;
> -
> -#if defined(DEBUG) || defined(XFS_WARN)
> -#define mrinit(mrp, name)	\
> -	do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
> -#else
> -#define mrinit(mrp, name)	\
> -	do { init_rwsem(&(mrp)->mr_lock); } while (0)
> -#endif
> -
> -#define mrlock_init(mrp, t,n,s)	mrinit(mrp, n)
> -#define mrfree(mrp)		do { } while (0)
> -
> -static inline void mraccess_nested(mrlock_t *mrp, int subclass)
> -{
> -	down_read_nested(&mrp->mr_lock, subclass);
> -}
> -
> -static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
> -{
> -	down_write_nested(&mrp->mr_lock, subclass);
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 1;
> -#endif
> -}
> -
> -static inline int mrtryaccess(mrlock_t *mrp)
> -{
> -	return down_read_trylock(&mrp->mr_lock);
> -}
> -
> -static inline int mrtryupdate(mrlock_t *mrp)
> -{
> -	if (!down_write_trylock(&mrp->mr_lock))
> -		return 0;
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 1;
> -#endif
> -	return 1;
> -}
> -
> -static inline void mrunlock_excl(mrlock_t *mrp)
> -{
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 0;
> -#endif
> -	up_write(&mrp->mr_lock);
> -}
> -
> -static inline void mrunlock_shared(mrlock_t *mrp)
> -{
> -	up_read(&mrp->mr_lock);
> -}
> -
> -static inline void mrdemote(mrlock_t *mrp)
> -{
> -#if defined(DEBUG) || defined(XFS_WARN)
> -	mrp->mr_writer = 0;
> -#endif
> -	downgrade_write(&mrp->mr_lock);
> -}
> -
> -#endif /* __XFS_SUPPORT_MRLOCK_H__ */
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 085927700530..f47202c487e0 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -191,14 +191,15 @@ xfs_ilock(
>  	}
>  
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrupdate_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
> +		down_write_nested(&ip->i_mmaplock,
> +				XFS_MMAPLOCK_DEP(lock_flags));
>  	else if (lock_flags & XFS_MMAPLOCK_SHARED)
> -		mraccess_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
> +		down_read_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
>  
>  	if (lock_flags & XFS_ILOCK_EXCL)
> -		mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
> +		down_write_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
>  	else if (lock_flags & XFS_ILOCK_SHARED)
> -		mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
> +		down_read_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
>  }
>  
>  /*
> @@ -242,27 +243,27 @@ xfs_ilock_nowait(
>  	}
>  
>  	if (lock_flags & XFS_MMAPLOCK_EXCL) {
> -		if (!mrtryupdate(&ip->i_mmaplock))
> +		if (!down_write_trylock(&ip->i_mmaplock))
>  			goto out_undo_iolock;
>  	} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
> -		if (!mrtryaccess(&ip->i_mmaplock))
> +		if (!down_read_trylock(&ip->i_mmaplock))
>  			goto out_undo_iolock;
>  	}
>  
>  	if (lock_flags & XFS_ILOCK_EXCL) {
> -		if (!mrtryupdate(&ip->i_lock))
> +		if (!down_write_trylock(&ip->i_lock))
>  			goto out_undo_mmaplock;
>  	} else if (lock_flags & XFS_ILOCK_SHARED) {
> -		if (!mrtryaccess(&ip->i_lock))
> +		if (!down_read_trylock(&ip->i_lock))
>  			goto out_undo_mmaplock;
>  	}
>  	return 1;
>  
>  out_undo_mmaplock:
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrunlock_excl(&ip->i_mmaplock);
> +		up_write(&ip->i_mmaplock);
>  	else if (lock_flags & XFS_MMAPLOCK_SHARED)
> -		mrunlock_shared(&ip->i_mmaplock);
> +		up_read(&ip->i_mmaplock);
>  out_undo_iolock:
>  	if (lock_flags & XFS_IOLOCK_EXCL)
>  		up_write(&VFS_I(ip)->i_rwsem);
> @@ -309,14 +310,14 @@ xfs_iunlock(
>  		up_read(&VFS_I(ip)->i_rwsem);
>  
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrunlock_excl(&ip->i_mmaplock);
> +		up_write(&ip->i_mmaplock);
>  	else if (lock_flags & XFS_MMAPLOCK_SHARED)
> -		mrunlock_shared(&ip->i_mmaplock);
> +		up_read(&ip->i_mmaplock);
>  
>  	if (lock_flags & XFS_ILOCK_EXCL)
> -		mrunlock_excl(&ip->i_lock);
> +		up_write(&ip->i_lock);
>  	else if (lock_flags & XFS_ILOCK_SHARED)
> -		mrunlock_shared(&ip->i_lock);
> +		up_read(&ip->i_lock);
>  
>  	trace_xfs_iunlock(ip, lock_flags, _RET_IP_);
>  }
> @@ -335,9 +336,9 @@ xfs_ilock_demote(
>  		~(XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
>  
>  	if (lock_flags & XFS_ILOCK_EXCL)
> -		mrdemote(&ip->i_lock);
> +		downgrade_write(&ip->i_lock);
>  	if (lock_flags & XFS_MMAPLOCK_EXCL)
> -		mrdemote(&ip->i_mmaplock);
> +		downgrade_write(&ip->i_mmaplock);
>  	if (lock_flags & XFS_IOLOCK_EXCL)
>  		downgrade_write(&VFS_I(ip)->i_rwsem);
>  
> @@ -375,19 +376,22 @@ xfs_isilocked(
>  	struct xfs_inode	*ip,
>  	uint			lock_flags)
>  {
> -	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
> -		if (!(lock_flags & XFS_ILOCK_SHARED))
> -			return !!ip->i_lock.mr_writer;
> -		return rwsem_is_locked(&ip->i_lock.mr_lock);
> +	if (lock_flags & (XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)) {
> +		ASSERT(!(lock_flags & ~(XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)));
> +		return __xfs_rwsem_islocked(&ip->i_lock, lock_flags,
> +				XFS_ILOCK_FLAG_SHIFT);
>  	}
>  
> -	if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
> -		if (!(lock_flags & XFS_MMAPLOCK_SHARED))
> -			return !!ip->i_mmaplock.mr_writer;
> -		return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
> +	if (lock_flags & (XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED)) {
> +		ASSERT(!(lock_flags &
> +			~(XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED)));
> +		return __xfs_rwsem_islocked(&ip->i_mmaplock, lock_flags,
> +				XFS_MMAPLOCK_FLAG_SHIFT);
>  	}
>  
>  	if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
> +		ASSERT(!(lock_flags &
> +			~(XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)));
>  		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem, lock_flags,
>  				XFS_IOLOCK_FLAG_SHIFT);
>  	}
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 9cecd6c9c90c..413998972b35 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -39,8 +39,8 @@ typedef struct xfs_inode {
>  
>  	/* Transaction and locking information. */
>  	struct xfs_inode_log_item *i_itemp;	/* logging information */
> -	mrlock_t		i_lock;		/* inode lock */
> -	mrlock_t		i_mmaplock;	/* inode mmap IO lock */
> +	struct rw_semaphore	i_lock;		/* inode lock */
> +	struct rw_semaphore	i_mmaplock;	/* inode mmap IO lock */
>  	atomic_t		i_pincount;	/* inode pin count */
>  
>  	/*
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 80a13c8561d8..66cca3e599c7 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -1336,9 +1336,9 @@ xfs_setup_inode(
>  		 */
>  		lockdep_set_class(&inode->i_rwsem,
>  				  &inode->i_sb->s_type->i_mutex_dir_key);
> -		lockdep_set_class(&ip->i_lock.mr_lock, &xfs_dir_ilock_class);
> +		lockdep_set_class(&ip->i_lock, &xfs_dir_ilock_class);
>  	} else {
> -		lockdep_set_class(&ip->i_lock.mr_lock, &xfs_nondir_ilock_class);
> +		lockdep_set_class(&ip->i_lock, &xfs_nondir_ilock_class);
>  	}
>  
>  	/*
> diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
> index ab737fed7b12..ba37217f86d2 100644
> --- a/fs/xfs/xfs_linux.h
> +++ b/fs/xfs/xfs_linux.h
> @@ -22,7 +22,6 @@ typedef __u32			xfs_nlink_t;
>  #include "xfs_types.h"
>  
>  #include "kmem.h"
> -#include "mrlock.h"
>  
>  #include <linux/semaphore.h>
>  #include <linux/mm.h>
> @@ -61,6 +60,7 @@ typedef __u32			xfs_nlink_t;
>  #include <linux/ratelimit.h>
>  #include <linux/rhashtable.h>
>  #include <linux/xattr.h>
> +#include <linux/rwsem.h>
>  
>  #include <asm/page.h>
>  #include <asm/div64.h>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 71ac6c1cdc36..00be9cfa29fa 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -708,10 +708,8 @@ xfs_fs_inode_init_once(
>  	atomic_set(&ip->i_pincount, 0);
>  	spin_lock_init(&ip->i_flags_lock);
>  
> -	mrlock_init(&ip->i_mmaplock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
> -		     "xfsino", ip->i_ino);
> -	mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
> -		     "xfsino", ip->i_ino);
> +	init_rwsem(&ip->i_mmaplock);
> +	init_rwsem(&ip->i_lock);
>  }
>  
>  /*
> -- 
> 2.26.2
> 

Re: [PATCH v12 4/4] xfs: replace mrlock_t with rw_semaphores

[Pavel Reichl]

 
> Looks ok to me.  Would you mind rebasing this against 5.10-rc1 so I can
> start testing a work branch with all the accumulated 5.11 stuff?

Hi,

version #13 is on the list - it's rebased against 5.10-rc1 and also contains the changes Brian proposed.

Bye.