diff mbox series

[07/14] xfs: Refactor xfs_isilocked()

Message ID 20210615091814.28626-7-jack@suse.cz (mailing list archive)
State New
Headers show
Series fs: Hole punch vs page cache filling races | expand

Commit Message

Jan Kara June 15, 2021, 9:17 a.m. UTC
From: Pavel Reichl <preichl@redhat.com>

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>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/xfs/xfs_inode.c | 34 ++++++++++++++++++++++++++--------
 fs/xfs/xfs_inode.h |  2 +-
 2 files changed, 27 insertions(+), 9 deletions(-)

Comments

Christoph Hellwig June 16, 2021, 5:37 a.m. UTC | #1
On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> From: Pavel Reichl <preichl@redhat.com>
> 
> 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.

__xfs_rwsem_islocked doesn't seem to actually existing in any tree I
checked yet?
Jan Kara June 16, 2021, 8:53 a.m. UTC | #2
On Wed 16-06-21 06:37:12, Christoph Hellwig wrote:
> On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > From: Pavel Reichl <preichl@redhat.com>
> > 
> > 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.
> 
> __xfs_rwsem_islocked doesn't seem to actually existing in any tree I
> checked yet?

__xfs_rwsem_islocked is introduced by this patch so I'm not sure what are
you asking about... :)

								Honza
Darrick J. Wong June 16, 2021, 3:47 p.m. UTC | #3
On Wed, Jun 16, 2021 at 10:53:04AM +0200, Jan Kara wrote:
> On Wed 16-06-21 06:37:12, Christoph Hellwig wrote:
> > On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > > From: Pavel Reichl <preichl@redhat.com>
> > > 
> > > 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.
> > 
> > __xfs_rwsem_islocked doesn't seem to actually existing in any tree I
> > checked yet?
> 
> __xfs_rwsem_islocked is introduced by this patch so I'm not sure what are
> you asking about... :)

The sentence structure implies that __xfs_rwsem_islocked was previously
introduced.  You might change the commit message to read:

"Introduce a new __xfs_rwsem_islocked predicate to encapsulate checking
the state of a rw_semaphore, then refactor xfs_isilocked to use it."

Since it's not quite a straight copy-paste of the old code.

--D

> 
> 								Honza
> 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
Jan Kara June 16, 2021, 3:57 p.m. UTC | #4
On Wed 16-06-21 08:47:05, Darrick J. Wong wrote:
> On Wed, Jun 16, 2021 at 10:53:04AM +0200, Jan Kara wrote:
> > On Wed 16-06-21 06:37:12, Christoph Hellwig wrote:
> > > On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > > > From: Pavel Reichl <preichl@redhat.com>
> > > > 
> > > > 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.
> > > 
> > > __xfs_rwsem_islocked doesn't seem to actually existing in any tree I
> > > checked yet?
> > 
> > __xfs_rwsem_islocked is introduced by this patch so I'm not sure what are
> > you asking about... :)
> 
> The sentence structure implies that __xfs_rwsem_islocked was previously
> introduced.  You might change the commit message to read:
> 
> "Introduce a new __xfs_rwsem_islocked predicate to encapsulate checking
> the state of a rw_semaphore, then refactor xfs_isilocked to use it."
> 
> Since it's not quite a straight copy-paste of the old code.

Ah, ok. Sure, I can rephrase the changelog (or we can just update it on
commit if that's the only problem with this series...). Oh, now I've
remembered I've promised you a branch to pull :) Here it is with this
change and Christoph's Reviewed-by tags:

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git hole_punch_fixes

								Honza
Christoph Hellwig June 17, 2021, 7:53 a.m. UTC | #5
On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> From: Pavel Reichl <preichl@redhat.com>
> 
> 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.

Looks good with the updated commit log:

Signed-off-by: Christoph Hellwig <hch@lst.de>
Jan Kara June 17, 2021, 8:53 a.m. UTC | #6
On Thu 17-06-21 08:53:28, Christoph Hellwig wrote:
> On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > From: Pavel Reichl <preichl@redhat.com>
> > 
> > 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.
> 
> Looks good with the updated commit log:
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

I suppose you mean Reviewed-by, don't you?

								Honza
Christoph Hellwig June 17, 2021, 8:54 a.m. UTC | #7
On Thu, Jun 17, 2021 at 10:53:19AM +0200, Jan Kara wrote:
> On Thu 17-06-21 08:53:28, Christoph Hellwig wrote:
> > On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > > From: Pavel Reichl <preichl@redhat.com>
> > > 
> > > 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.
> > 
> > Looks good with the updated commit log:
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> I suppose you mean Reviewed-by, don't you?

Yes:

Reviewed-by: Christoph Hellwig <hch@lst.de>
Darrick J. Wong June 17, 2021, 4:16 p.m. UTC | #8
On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> From: Pavel Reichl <preichl@redhat.com>
> 
> 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>
> Signed-off-by: Jan Kara <jack@suse.cz>

With the commit message updated,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_inode.c | 34 ++++++++++++++++++++++++++--------
>  fs/xfs/xfs_inode.h |  2 +-
>  2 files changed, 27 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index e4c2da4566f1..ffd47217a8fa 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -342,9 +342,29 @@ xfs_ilock_demote(
>  }
>  
>  #if defined(DEBUG) || defined(XFS_WARN)
> -int
> +static inline bool
> +__xfs_rwsem_islocked(
> +	struct rw_semaphore	*rwsem,
> +	bool			shared)
> +{
> +	if (!debug_locks)
> +		return rwsem_is_locked(rwsem);
> +
> +	if (!shared)
> +		return lockdep_is_held_type(rwsem, 0);
> +
> +	/*
> +	 * We are checking that the lock is held at least in shared
> +	 * mode but don't care that it might be held exclusively
> +	 * (i.e. shared | excl). Hence we check if the lock is held
> +	 * in any mode rather than an explicit shared mode.
> +	 */
> +	return lockdep_is_held_type(rwsem, -1);
> +}
> +
> +bool
>  xfs_isilocked(
> -	xfs_inode_t		*ip,
> +	struct xfs_inode	*ip,
>  	uint			lock_flags)
>  {
>  	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
> @@ -359,15 +379,13 @@ 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_SHARED));
>  	}
>  
>  	ASSERT(0);
> -	return 0;
> +	return false;
>  }
>  #endif
>  
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index ca826cfba91c..4659e1568966 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -410,7 +410,7 @@ 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
>
Darrick J. Wong June 17, 2021, 4:29 p.m. UTC | #9
On Wed, Jun 16, 2021 at 05:57:12PM +0200, Jan Kara wrote:
> On Wed 16-06-21 08:47:05, Darrick J. Wong wrote:
> > On Wed, Jun 16, 2021 at 10:53:04AM +0200, Jan Kara wrote:
> > > On Wed 16-06-21 06:37:12, Christoph Hellwig wrote:
> > > > On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > > > > From: Pavel Reichl <preichl@redhat.com>
> > > > > 
> > > > > 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.
> > > > 
> > > > __xfs_rwsem_islocked doesn't seem to actually existing in any tree I
> > > > checked yet?
> > > 
> > > __xfs_rwsem_islocked is introduced by this patch so I'm not sure what are
> > > you asking about... :)
> > 
> > The sentence structure implies that __xfs_rwsem_islocked was previously
> > introduced.  You might change the commit message to read:
> > 
> > "Introduce a new __xfs_rwsem_islocked predicate to encapsulate checking
> > the state of a rw_semaphore, then refactor xfs_isilocked to use it."
> > 
> > Since it's not quite a straight copy-paste of the old code.
> 
> Ah, ok. Sure, I can rephrase the changelog (or we can just update it on
> commit if that's the only problem with this series...). Oh, now I've
> remembered I've promised you a branch to pull :) Here it is with this
> change and Christoph's Reviewed-by tags:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git hole_punch_fixes

To catch-up the list with the ext4 concall:

Dave Chinner and I have been experimenting with accepting tagged pull
requests, where the tag message is the most recent cover letter so that
the git history can capture the broader justification for the series and
the development revision history.  Signed tags would be ideal too,
though given the impossibility of meeting in person to exchange gnupg
keys (and the fact that one has to verify that the patches in the branch
more or less match what's on the list) I don't consider that an
impediment.

Also, if you want me to take this through the xfs tree then it would
make things much easier if you could base this branch off 5.13-rc4, or
something that won't cause a merge request to pull in a bunch of
unrelated upstream changes.

--D

> 
> 								Honza
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
Darrick J. Wong June 17, 2021, 4:32 p.m. UTC | #10
On Thu, Jun 17, 2021 at 09:29:20AM -0700, Darrick J. Wong wrote:
> On Wed, Jun 16, 2021 at 05:57:12PM +0200, Jan Kara wrote:
> > On Wed 16-06-21 08:47:05, Darrick J. Wong wrote:
> > > On Wed, Jun 16, 2021 at 10:53:04AM +0200, Jan Kara wrote:
> > > > On Wed 16-06-21 06:37:12, Christoph Hellwig wrote:
> > > > > On Tue, Jun 15, 2021 at 11:17:57AM +0200, Jan Kara wrote:
> > > > > > From: Pavel Reichl <preichl@redhat.com>
> > > > > > 
> > > > > > 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.
> > > > > 
> > > > > __xfs_rwsem_islocked doesn't seem to actually existing in any tree I
> > > > > checked yet?
> > > > 
> > > > __xfs_rwsem_islocked is introduced by this patch so I'm not sure what are
> > > > you asking about... :)
> > > 
> > > The sentence structure implies that __xfs_rwsem_islocked was previously
> > > introduced.  You might change the commit message to read:
> > > 
> > > "Introduce a new __xfs_rwsem_islocked predicate to encapsulate checking
> > > the state of a rw_semaphore, then refactor xfs_isilocked to use it."
> > > 
> > > Since it's not quite a straight copy-paste of the old code.
> > 
> > Ah, ok. Sure, I can rephrase the changelog (or we can just update it on
> > commit if that's the only problem with this series...). Oh, now I've
> > remembered I've promised you a branch to pull :) Here it is with this
> > change and Christoph's Reviewed-by tags:
> > 
> > git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git hole_punch_fixes
> 
> To catch-up the list with the ext4 concall:
> 
> Dave Chinner and I have been experimenting with accepting tagged pull
> requests, where the tag message is the most recent cover letter so that
> the git history can capture the broader justification for the series and
> the development revision history.  Signed tags would be ideal too,
> though given the impossibility of meeting in person to exchange gnupg
> keys (and the fact that one has to verify that the patches in the branch
> more or less match what's on the list) I don't consider that an
> impediment.
> 
> Also, if you want me to take this through the xfs tree then it would
> make things much easier if you could base this branch off 5.13-rc4, or
> something that won't cause a merge request to pull in a bunch of
> unrelated upstream changes.

Oh, and also: Please send pull requests as a new thread tagged '[GIT
PULL]' so the requests don't get buried in a patch reply thread.

--D

> --D
> 
> > 
> > 								Honza
> > -- 
> > Jan Kara <jack@suse.com>
> > SUSE Labs, CR
diff mbox series

Patch

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index e4c2da4566f1..ffd47217a8fa 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -342,9 +342,29 @@  xfs_ilock_demote(
 }
 
 #if defined(DEBUG) || defined(XFS_WARN)
-int
+static inline bool
+__xfs_rwsem_islocked(
+	struct rw_semaphore	*rwsem,
+	bool			shared)
+{
+	if (!debug_locks)
+		return rwsem_is_locked(rwsem);
+
+	if (!shared)
+		return lockdep_is_held_type(rwsem, 0);
+
+	/*
+	 * We are checking that the lock is held at least in shared
+	 * mode but don't care that it might be held exclusively
+	 * (i.e. shared | excl). Hence we check if the lock is held
+	 * in any mode rather than an explicit shared mode.
+	 */
+	return lockdep_is_held_type(rwsem, -1);
+}
+
+bool
 xfs_isilocked(
-	xfs_inode_t		*ip,
+	struct xfs_inode	*ip,
 	uint			lock_flags)
 {
 	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
@@ -359,15 +379,13 @@  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_SHARED));
 	}
 
 	ASSERT(0);
-	return 0;
+	return false;
 }
 #endif
 
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index ca826cfba91c..4659e1568966 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -410,7 +410,7 @@  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 *);