misc cleanups to the resblks interfaces

misc cleanups to the resblks interfaces

[Christoph Hellwig]

Hi all,

this series has small cosmetics to the get/set reslks and fscounts
interface.

Diffstat:
 xfs_fsops.c |   50 +-------------------------
 xfs_fsops.h |   14 +++----
 xfs_ioctl.c |  115 ++++++++++++++++++++++++++++++++----------------------------
 xfs_mount.c |    8 +---
 xfs_super.c |    6 +--
 5 files changed, 75 insertions(+), 118 deletions(-)

[PATCH 1/4] xfs: clean up the XFS_IOC_{GS}ET_RESBLKS handler

[Christoph Hellwig]

The XFS_IOC_GET_RESBLKS and XFS_IOC_SET_RESBLKS already share a fair
amount of code, and will share even more soon.  Move the logic for both
of them out of the main xfs_file_ioctl function into a
xfs_ioctl_getset_resblocks helper to share the code and prepare for
additional changes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_ioctl.c | 87 +++++++++++++++++++++++-----------------------
 1 file changed, 43 insertions(+), 44 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index a82470e027f727..8faaf2ef67a7b8 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1862,6 +1862,46 @@ xfs_fs_eofblocks_from_user(
 	return 0;
 }
 
+static int
+xfs_ioctl_getset_resblocks(
+	struct file		*filp,
+	unsigned int		cmd,
+	void __user		*arg)
+{
+	struct xfs_mount	*mp = XFS_I(file_inode(filp))->i_mount;
+	struct xfs_fsop_resblks	fsop = { };
+	int			error;
+	uint64_t		in;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (cmd == XFS_IOC_SET_RESBLKS) {
+		if (xfs_is_readonly(mp))
+			return -EROFS;
+
+		if (copy_from_user(&fsop, arg, sizeof(fsop)))
+			return -EFAULT;
+
+		error = mnt_want_write_file(filp);
+		if (error)
+			return error;
+		in = fsop.resblks;
+		error = xfs_reserve_blocks(mp, &in, &fsop);
+		mnt_drop_write_file(filp);
+		if (error)
+			return error;
+	} else {
+		error = xfs_reserve_blocks(mp, NULL, &fsop);
+		if (error)
+			return error;
+	}
+
+	if (copy_to_user(arg, &fsop, sizeof(fsop)))
+		return -EFAULT;
+	return 0;
+}
+
 /*
  * These long-unused ioctls were removed from the official ioctl API in 5.17,
  * but retain these definitions so that we can log warnings about them.
@@ -2008,50 +2048,9 @@ xfs_file_ioctl(
 		return 0;
 	}
 
-	case XFS_IOC_SET_RESBLKS: {
-		xfs_fsop_resblks_t inout;
-		uint64_t	   in;
-
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-
-		if (xfs_is_readonly(mp))
-			return -EROFS;
-
-		if (copy_from_user(&inout, arg, sizeof(inout)))
-			return -EFAULT;
-
-		error = mnt_want_write_file(filp);
-		if (error)
-			return error;
-
-		/* input parameter is passed in resblks field of structure */
-		in = inout.resblks;
-		error = xfs_reserve_blocks(mp, &in, &inout);
-		mnt_drop_write_file(filp);
-		if (error)
-			return error;
-
-		if (copy_to_user(arg, &inout, sizeof(inout)))
-			return -EFAULT;
-		return 0;
-	}
-
-	case XFS_IOC_GET_RESBLKS: {
-		xfs_fsop_resblks_t out;
-
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-
-		error = xfs_reserve_blocks(mp, NULL, &out);
-		if (error)
-			return error;
-
-		if (copy_to_user(arg, &out, sizeof(out)))
-			return -EFAULT;
-
-		return 0;
-	}
+	case XFS_IOC_SET_RESBLKS:
+	case XFS_IOC_GET_RESBLKS:
+		return xfs_ioctl_getset_resblocks(filp, cmd, arg);
 
 	case XFS_IOC_FSGROWFSDATA: {
 		struct xfs_growfs_data in;
-- 
2.39.2

Re: [PATCH 1/4] xfs: clean up the XFS_IOC_{GS}ET_RESBLKS handler

[Darrick J. Wong]

On Sun, Nov 26, 2023 at 02:01:21PM +0100, Christoph Hellwig wrote:
> The XFS_IOC_GET_RESBLKS and XFS_IOC_SET_RESBLKS already share a fair
> amount of code, and will share even more soon.  Move the logic for both
> of them out of the main xfs_file_ioctl function into a
> xfs_ioctl_getset_resblocks helper to share the code and prepare for
> additional changes.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_ioctl.c | 87 +++++++++++++++++++++++-----------------------
>  1 file changed, 43 insertions(+), 44 deletions(-)
> 
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index a82470e027f727..8faaf2ef67a7b8 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1862,6 +1862,46 @@ xfs_fs_eofblocks_from_user(
>  	return 0;
>  }
>  
> +static int
> +xfs_ioctl_getset_resblocks(
> +	struct file		*filp,
> +	unsigned int		cmd,
> +	void __user		*arg)
> +{
> +	struct xfs_mount	*mp = XFS_I(file_inode(filp))->i_mount;
> +	struct xfs_fsop_resblks	fsop = { };
> +	int			error;
> +	uint64_t		in;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	if (cmd == XFS_IOC_SET_RESBLKS) {
> +		if (xfs_is_readonly(mp))
> +			return -EROFS;
> +
> +		if (copy_from_user(&fsop, arg, sizeof(fsop)))
> +			return -EFAULT;
> +
> +		error = mnt_want_write_file(filp);
> +		if (error)
> +			return error;
> +		in = fsop.resblks;
> +		error = xfs_reserve_blocks(mp, &in, &fsop);

<shudder> what an interface...
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> +		mnt_drop_write_file(filp);
> +		if (error)
> +			return error;
> +	} else {
> +		error = xfs_reserve_blocks(mp, NULL, &fsop);
> +		if (error)
> +			return error;
> +	}
> +
> +	if (copy_to_user(arg, &fsop, sizeof(fsop)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
>  /*
>   * These long-unused ioctls were removed from the official ioctl API in 5.17,
>   * but retain these definitions so that we can log warnings about them.
> @@ -2008,50 +2048,9 @@ xfs_file_ioctl(
>  		return 0;
>  	}
>  
> -	case XFS_IOC_SET_RESBLKS: {
> -		xfs_fsop_resblks_t inout;
> -		uint64_t	   in;
> -
> -		if (!capable(CAP_SYS_ADMIN))
> -			return -EPERM;
> -
> -		if (xfs_is_readonly(mp))
> -			return -EROFS;
> -
> -		if (copy_from_user(&inout, arg, sizeof(inout)))
> -			return -EFAULT;
> -
> -		error = mnt_want_write_file(filp);
> -		if (error)
> -			return error;
> -
> -		/* input parameter is passed in resblks field of structure */
> -		in = inout.resblks;
> -		error = xfs_reserve_blocks(mp, &in, &inout);
> -		mnt_drop_write_file(filp);
> -		if (error)
> -			return error;
> -
> -		if (copy_to_user(arg, &inout, sizeof(inout)))
> -			return -EFAULT;
> -		return 0;
> -	}
> -
> -	case XFS_IOC_GET_RESBLKS: {
> -		xfs_fsop_resblks_t out;
> -
> -		if (!capable(CAP_SYS_ADMIN))
> -			return -EPERM;
> -
> -		error = xfs_reserve_blocks(mp, NULL, &out);
> -		if (error)
> -			return error;
> -
> -		if (copy_to_user(arg, &out, sizeof(out)))
> -			return -EFAULT;
> -
> -		return 0;
> -	}
> +	case XFS_IOC_SET_RESBLKS:
> +	case XFS_IOC_GET_RESBLKS:
> +		return xfs_ioctl_getset_resblocks(filp, cmd, arg);
>  
>  	case XFS_IOC_FSGROWFSDATA: {
>  		struct xfs_growfs_data in;
> -- 
> 2.39.2
> 
> 

[PATCH 2/4] xfs: clean up the XFS_IOC_FSCOUNTS handler

[Christoph Hellwig]

Split XFS_IOC_FSCOUNTS out of the main xfs_file_ioctl function, and
merge the xfs_fs_counts helper into the ioctl handler.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_fsops.c | 16 ----------------
 fs/xfs/xfs_fsops.h |  1 -
 fs/xfs/xfs_ioctl.c | 29 ++++++++++++++++++++---------
 3 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 7cb75cb6b8e9b4..01681783e2c31a 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -343,22 +343,6 @@ xfs_growfs_log(
 	return error;
 }
 
-/*
- * exported through ioctl XFS_IOC_FSCOUNTS
- */
-
-void
-xfs_fs_counts(
-	xfs_mount_t		*mp,
-	xfs_fsop_counts_t	*cnt)
-{
-	cnt->allocino = percpu_counter_read_positive(&mp->m_icount);
-	cnt->freeino = percpu_counter_read_positive(&mp->m_ifree);
-	cnt->freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
-						xfs_fdblocks_unavailable(mp);
-	cnt->freertx = percpu_counter_read_positive(&mp->m_frextents);
-}
-
 /*
  * exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
  *
diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index 2cffe51a31e8b2..45f0cb6e805938 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -8,7 +8,6 @@
 
 extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
 extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
-extern void xfs_fs_counts(xfs_mount_t *mp, xfs_fsop_counts_t *cnt);
 extern int xfs_reserve_blocks(xfs_mount_t *mp, uint64_t *inval,
 				xfs_fsop_resblks_t *outval);
 extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 8faaf2ef67a7b8..c8e78c8101c65c 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1902,6 +1902,24 @@ xfs_ioctl_getset_resblocks(
 	return 0;
 }
 
+static int
+xfs_ioctl_fs_counts(
+	struct xfs_mount	*mp,
+	struct xfs_fsop_counts	*uarg)
+{
+	struct xfs_fsop_counts	out = {
+		.allocino = percpu_counter_read_positive(&mp->m_icount),
+		.freeino = percpu_counter_read_positive(&mp->m_ifree),
+		.freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
+				xfs_fdblocks_unavailable(mp),
+		.freertx = percpu_counter_read_positive(&mp->m_frextents),
+	};
+
+	if (copy_to_user(uarg, &out, sizeof(out)))
+		return -EFAULT;
+	return 0;
+}
+
 /*
  * These long-unused ioctls were removed from the official ioctl API in 5.17,
  * but retain these definitions so that we can log warnings about them.
@@ -2038,15 +2056,8 @@ xfs_file_ioctl(
 		return error;
 	}
 
-	case XFS_IOC_FSCOUNTS: {
-		xfs_fsop_counts_t out;
-
-		xfs_fs_counts(mp, &out);
-
-		if (copy_to_user(arg, &out, sizeof(out)))
-			return -EFAULT;
-		return 0;
-	}
+	case XFS_IOC_FSCOUNTS:
+		return xfs_ioctl_fs_counts(mp, arg);
 
 	case XFS_IOC_SET_RESBLKS:
 	case XFS_IOC_GET_RESBLKS:
-- 
2.39.2

Re: [PATCH 2/4] xfs: clean up the XFS_IOC_FSCOUNTS handler

[Christoph Hellwig]

> +static int
> +xfs_ioctl_fs_counts(
> +	struct xfs_mount	*mp,
> +	struct xfs_fsop_counts	*uarg)

FYI, the buildbot (rightly) complained about a missing __user
annotation for sparse here.

Re: [PATCH 2/4] xfs: clean up the XFS_IOC_FSCOUNTS handler

[Darrick J. Wong]

On Sun, Nov 26, 2023 at 02:01:22PM +0100, Christoph Hellwig wrote:
> Split XFS_IOC_FSCOUNTS out of the main xfs_file_ioctl function, and
> merge the xfs_fs_counts helper into the ioctl handler.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_fsops.c | 16 ----------------
>  fs/xfs/xfs_fsops.h |  1 -
>  fs/xfs/xfs_ioctl.c | 29 ++++++++++++++++++++---------
>  3 files changed, 20 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 7cb75cb6b8e9b4..01681783e2c31a 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -343,22 +343,6 @@ xfs_growfs_log(
>  	return error;
>  }
>  
> -/*
> - * exported through ioctl XFS_IOC_FSCOUNTS
> - */
> -
> -void
> -xfs_fs_counts(
> -	xfs_mount_t		*mp,
> -	xfs_fsop_counts_t	*cnt)
> -{
> -	cnt->allocino = percpu_counter_read_positive(&mp->m_icount);
> -	cnt->freeino = percpu_counter_read_positive(&mp->m_ifree);
> -	cnt->freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
> -						xfs_fdblocks_unavailable(mp);
> -	cnt->freertx = percpu_counter_read_positive(&mp->m_frextents);
> -}
> -
>  /*
>   * exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
>   *
> diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
> index 2cffe51a31e8b2..45f0cb6e805938 100644
> --- a/fs/xfs/xfs_fsops.h
> +++ b/fs/xfs/xfs_fsops.h
> @@ -8,7 +8,6 @@
>  
>  extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
>  extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
> -extern void xfs_fs_counts(xfs_mount_t *mp, xfs_fsop_counts_t *cnt);
>  extern int xfs_reserve_blocks(xfs_mount_t *mp, uint64_t *inval,
>  				xfs_fsop_resblks_t *outval);
>  extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 8faaf2ef67a7b8..c8e78c8101c65c 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1902,6 +1902,24 @@ xfs_ioctl_getset_resblocks(
>  	return 0;
>  }
>  
> +static int
> +xfs_ioctl_fs_counts(
> +	struct xfs_mount	*mp,
> +	struct xfs_fsop_counts	*uarg)
> +{
> +	struct xfs_fsop_counts	out = {
> +		.allocino = percpu_counter_read_positive(&mp->m_icount),
> +		.freeino = percpu_counter_read_positive(&mp->m_ifree),
> +		.freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
> +				xfs_fdblocks_unavailable(mp),
> +		.freertx = percpu_counter_read_positive(&mp->m_frextents),
> +	};

	struct xfs_fsop_counts	out = {
		.allocino = percpu_counter_read_positive(&mp->m_icount),
		.freeino  = percpu_counter_read_positive(&mp->m_ifree),
		.freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
						xfs_fdblocks_unavailable(mp),
		.freertx  = percpu_counter_read_positive(&mp->m_frextents),
	};

Nit: Would you mind lining up the columns?

Otherwise looks good to me,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D


> +
> +	if (copy_to_user(uarg, &out, sizeof(out)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
>  /*
>   * These long-unused ioctls were removed from the official ioctl API in 5.17,
>   * but retain these definitions so that we can log warnings about them.
> @@ -2038,15 +2056,8 @@ xfs_file_ioctl(
>  		return error;
>  	}
>  
> -	case XFS_IOC_FSCOUNTS: {
> -		xfs_fsop_counts_t out;
> -
> -		xfs_fs_counts(mp, &out);
> -
> -		if (copy_to_user(arg, &out, sizeof(out)))
> -			return -EFAULT;
> -		return 0;
> -	}
> +	case XFS_IOC_FSCOUNTS:
> +		return xfs_ioctl_fs_counts(mp, arg);
>  
>  	case XFS_IOC_SET_RESBLKS:
>  	case XFS_IOC_GET_RESBLKS:
> -- 
> 2.39.2
> 
> 

Re: [PATCH 2/4] xfs: clean up the XFS_IOC_FSCOUNTS handler

[Christoph Hellwig]

On Mon, Nov 27, 2023 at 05:58:12PM -0800, Darrick J. Wong wrote:
> 	struct xfs_fsop_counts	out = {
> 		.allocino = percpu_counter_read_positive(&mp->m_icount),
> 		.freeino  = percpu_counter_read_positive(&mp->m_ifree),
> 		.freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
> 						xfs_fdblocks_unavailable(mp),
> 		.freertx  = percpu_counter_read_positive(&mp->m_frextents),
> 	};
> 
> Nit: Would you mind lining up the columns?

Sure.  I need to respin for the __user annotation anyway.

[PATCH 3/4] xfs: clean up the xfs_reserve_blocks interface

[Christoph Hellwig]

xfs_reserve_blocks has a very odd interface that can only be explained
by it directly deriving from the IRIX fcntl handler back in the day.

Split reporting out the reserved blocks out of xfs_reserve_blocks into
the only caller that cares.  This means that the value reported from
XFS_IOC_SET_RESBLKS isn't atomically sampled in the same critical
section as when it was set anymore, but as the values could change
right after setting them anyway that does not matter.  It does
provide atomic sampling of both values for XFS_IOC_GET_RESBLKS now,
though.

Also pass a normal scalar integer value for the requested value instead
of the pointless pointer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_fsops.c | 34 +++-------------------------------
 fs/xfs/xfs_fsops.h |  3 +--
 fs/xfs/xfs_ioctl.c | 13 ++++++-------
 fs/xfs/xfs_mount.c |  8 ++------
 fs/xfs/xfs_super.c |  6 ++----
 5 files changed, 14 insertions(+), 50 deletions(-)

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 01681783e2c31a..4f5da19142f298 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -344,43 +344,20 @@ xfs_growfs_log(
 }
 
 /*
- * exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
- *
- * xfs_reserve_blocks is called to set m_resblks
- * in the in-core mount table. The number of unused reserved blocks
- * is kept in m_resblks_avail.
- *
  * Reserve the requested number of blocks if available. Otherwise return
  * as many as possible to satisfy the request. The actual number
- * reserved are returned in outval
- *
- * A null inval pointer indicates that only the current reserved blocks
- * available  should  be returned no settings are changed.
+ * reserved are returned in outval.
  */
-
 int
 xfs_reserve_blocks(
-	xfs_mount_t             *mp,
-	uint64_t              *inval,
-	xfs_fsop_resblks_t      *outval)
+	struct xfs_mount	*mp,
+	uint64_t		request)
 {
 	int64_t			lcounter, delta;
 	int64_t			fdblks_delta = 0;
-	uint64_t		request;
 	int64_t			free;
 	int			error = 0;
 
-	/* If inval is null, report current values and return */
-	if (inval == (uint64_t *)NULL) {
-		if (!outval)
-			return -EINVAL;
-		outval->resblks = mp->m_resblks;
-		outval->resblks_avail = mp->m_resblks_avail;
-		return 0;
-	}
-
-	request = *inval;
-
 	/*
 	 * With per-cpu counters, this becomes an interesting problem. we need
 	 * to work out if we are freeing or allocation blocks first, then we can
@@ -450,11 +427,6 @@ xfs_reserve_blocks(
 		spin_lock(&mp->m_sb_lock);
 	}
 out:
-	if (outval) {
-		outval->resblks = mp->m_resblks;
-		outval->resblks_avail = mp->m_resblks_avail;
-	}
-
 	spin_unlock(&mp->m_sb_lock);
 	return error;
 }
diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index 45f0cb6e805938..7536f8a92746f6 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -8,8 +8,7 @@
 
 extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
 extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
-extern int xfs_reserve_blocks(xfs_mount_t *mp, uint64_t *inval,
-				xfs_fsop_resblks_t *outval);
+int xfs_reserve_blocks(struct xfs_mount *mp, uint64_t request);
 extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
 
 extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index c8e78c8101c65c..812efb7923abb1 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1871,7 +1871,6 @@ xfs_ioctl_getset_resblocks(
 	struct xfs_mount	*mp = XFS_I(file_inode(filp))->i_mount;
 	struct xfs_fsop_resblks	fsop = { };
 	int			error;
-	uint64_t		in;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -1886,17 +1885,17 @@ xfs_ioctl_getset_resblocks(
 		error = mnt_want_write_file(filp);
 		if (error)
 			return error;
-		in = fsop.resblks;
-		error = xfs_reserve_blocks(mp, &in, &fsop);
+		error = xfs_reserve_blocks(mp, fsop.resblks);
 		mnt_drop_write_file(filp);
 		if (error)
 			return error;
-	} else {
-		error = xfs_reserve_blocks(mp, NULL, &fsop);
-		if (error)
-			return error;
 	}
 
+	spin_lock(&mp->m_sb_lock);
+	fsop.resblks = mp->m_resblks;
+	fsop.resblks_avail = mp->m_resblks_avail;
+	spin_unlock(&mp->m_sb_lock);
+
 	if (copy_to_user(arg, &fsop, sizeof(fsop)))
 		return -EFAULT;
 	return 0;
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index aed5be5508fe57..aabb25dc3efab2 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -637,7 +637,6 @@ xfs_mountfs(
 	struct xfs_sb		*sbp = &(mp->m_sb);
 	struct xfs_inode	*rip;
 	struct xfs_ino_geometry	*igeo = M_IGEO(mp);
-	uint64_t		resblks;
 	uint			quotamount = 0;
 	uint			quotaflags = 0;
 	int			error = 0;
@@ -974,8 +973,7 @@ xfs_mountfs(
 	 * we were already there on the last unmount. Warn if this occurs.
 	 */
 	if (!xfs_is_readonly(mp)) {
-		resblks = xfs_default_resblks(mp);
-		error = xfs_reserve_blocks(mp, &resblks, NULL);
+		error = xfs_reserve_blocks(mp, xfs_default_resblks(mp));
 		if (error)
 			xfs_warn(mp,
 	"Unable to allocate reserve blocks. Continuing without reserve pool.");
@@ -1053,7 +1051,6 @@ void
 xfs_unmountfs(
 	struct xfs_mount	*mp)
 {
-	uint64_t		resblks;
 	int			error;
 
 	/*
@@ -1090,8 +1087,7 @@ xfs_unmountfs(
 	 * we only every apply deltas to the superblock and hence the incore
 	 * value does not matter....
 	 */
-	resblks = 0;
-	error = xfs_reserve_blocks(mp, &resblks, NULL);
+	error = xfs_reserve_blocks(mp, 0);
 	if (error)
 		xfs_warn(mp, "Unable to free reserved block pool. "
 				"Freespace may not be correct on next mount.");
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 764304595e8b00..d0009430a62778 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -906,10 +906,8 @@ xfs_fs_statfs(
 STATIC void
 xfs_save_resvblks(struct xfs_mount *mp)
 {
-	uint64_t resblks = 0;
-
 	mp->m_resblks_save = mp->m_resblks;
-	xfs_reserve_blocks(mp, &resblks, NULL);
+	xfs_reserve_blocks(mp, 0);
 }
 
 STATIC void
@@ -923,7 +921,7 @@ xfs_restore_resvblks(struct xfs_mount *mp)
 	} else
 		resblks = xfs_default_resblks(mp);
 
-	xfs_reserve_blocks(mp, &resblks, NULL);
+	xfs_reserve_blocks(mp, resblks);
 }
 
 /*
-- 
2.39.2

Re: [PATCH 3/4] xfs: clean up the xfs_reserve_blocks interface

[Darrick J. Wong]

On Sun, Nov 26, 2023 at 02:01:23PM +0100, Christoph Hellwig wrote:
> xfs_reserve_blocks has a very odd interface that can only be explained
> by it directly deriving from the IRIX fcntl handler back in the day.
> 
> Split reporting out the reserved blocks out of xfs_reserve_blocks into
> the only caller that cares.  This means that the value reported from
> XFS_IOC_SET_RESBLKS isn't atomically sampled in the same critical
> section as when it was set anymore, but as the values could change

That wasn't true for the case of increasing the reserve before this
patch either. :)

> right after setting them anyway that does not matter.  It does
> provide atomic sampling of both values for XFS_IOC_GET_RESBLKS now,
> though.

Hey, that's neat!

> Also pass a normal scalar integer value for the requested value instead
> of the pointless pointer.

Guh.  What a calling convention.

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_fsops.c | 34 +++-------------------------------
>  fs/xfs/xfs_fsops.h |  3 +--
>  fs/xfs/xfs_ioctl.c | 13 ++++++-------
>  fs/xfs/xfs_mount.c |  8 ++------
>  fs/xfs/xfs_super.c |  6 ++----
>  5 files changed, 14 insertions(+), 50 deletions(-)
> 
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 01681783e2c31a..4f5da19142f298 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -344,43 +344,20 @@ xfs_growfs_log(
>  }
>  
>  /*
> - * exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
> - *
> - * xfs_reserve_blocks is called to set m_resblks
> - * in the in-core mount table. The number of unused reserved blocks
> - * is kept in m_resblks_avail.
> - *
>   * Reserve the requested number of blocks if available. Otherwise return
>   * as many as possible to satisfy the request. The actual number
> - * reserved are returned in outval
> - *
> - * A null inval pointer indicates that only the current reserved blocks
> - * available  should  be returned no settings are changed.
> + * reserved are returned in outval.
>   */
> -
>  int
>  xfs_reserve_blocks(
> -	xfs_mount_t             *mp,
> -	uint64_t              *inval,
> -	xfs_fsop_resblks_t      *outval)
> +	struct xfs_mount	*mp,
> +	uint64_t		request)
>  {
>  	int64_t			lcounter, delta;
>  	int64_t			fdblks_delta = 0;
> -	uint64_t		request;
>  	int64_t			free;
>  	int			error = 0;
>  
> -	/* If inval is null, report current values and return */
> -	if (inval == (uint64_t *)NULL) {
> -		if (!outval)
> -			return -EINVAL;
> -		outval->resblks = mp->m_resblks;
> -		outval->resblks_avail = mp->m_resblks_avail;
> -		return 0;
> -	}
> -
> -	request = *inval;
> -
>  	/*
>  	 * With per-cpu counters, this becomes an interesting problem. we need
>  	 * to work out if we are freeing or allocation blocks first, then we can
> @@ -450,11 +427,6 @@ xfs_reserve_blocks(
>  		spin_lock(&mp->m_sb_lock);
>  	}
>  out:
> -	if (outval) {
> -		outval->resblks = mp->m_resblks;
> -		outval->resblks_avail = mp->m_resblks_avail;
> -	}
> -
>  	spin_unlock(&mp->m_sb_lock);
>  	return error;
>  }
> diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
> index 45f0cb6e805938..7536f8a92746f6 100644
> --- a/fs/xfs/xfs_fsops.h
> +++ b/fs/xfs/xfs_fsops.h
> @@ -8,8 +8,7 @@
>  
>  extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
>  extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
> -extern int xfs_reserve_blocks(xfs_mount_t *mp, uint64_t *inval,
> -				xfs_fsop_resblks_t *outval);
> +int xfs_reserve_blocks(struct xfs_mount *mp, uint64_t request);
>  extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
>  
>  extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index c8e78c8101c65c..812efb7923abb1 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1871,7 +1871,6 @@ xfs_ioctl_getset_resblocks(
>  	struct xfs_mount	*mp = XFS_I(file_inode(filp))->i_mount;
>  	struct xfs_fsop_resblks	fsop = { };
>  	int			error;
> -	uint64_t		in;
>  
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EPERM;
> @@ -1886,17 +1885,17 @@ xfs_ioctl_getset_resblocks(
>  		error = mnt_want_write_file(filp);
>  		if (error)
>  			return error;
> -		in = fsop.resblks;
> -		error = xfs_reserve_blocks(mp, &in, &fsop);
> +		error = xfs_reserve_blocks(mp, fsop.resblks);
>  		mnt_drop_write_file(filp);
>  		if (error)
>  			return error;
> -	} else {
> -		error = xfs_reserve_blocks(mp, NULL, &fsop);
> -		if (error)
> -			return error;
>  	}
>  
> +	spin_lock(&mp->m_sb_lock);
> +	fsop.resblks = mp->m_resblks;
> +	fsop.resblks_avail = mp->m_resblks_avail;
> +	spin_unlock(&mp->m_sb_lock);

Hm.  I sorta preferred keeping these details hidden in xfs_fsops.c
rather than scattering them around and lengthening xfs_ioctl.c, but
I think the calling convention cleanup is worthy enough for:

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> +
>  	if (copy_to_user(arg, &fsop, sizeof(fsop)))
>  		return -EFAULT;
>  	return 0;
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index aed5be5508fe57..aabb25dc3efab2 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -637,7 +637,6 @@ xfs_mountfs(
>  	struct xfs_sb		*sbp = &(mp->m_sb);
>  	struct xfs_inode	*rip;
>  	struct xfs_ino_geometry	*igeo = M_IGEO(mp);
> -	uint64_t		resblks;
>  	uint			quotamount = 0;
>  	uint			quotaflags = 0;
>  	int			error = 0;
> @@ -974,8 +973,7 @@ xfs_mountfs(
>  	 * we were already there on the last unmount. Warn if this occurs.
>  	 */
>  	if (!xfs_is_readonly(mp)) {
> -		resblks = xfs_default_resblks(mp);
> -		error = xfs_reserve_blocks(mp, &resblks, NULL);
> +		error = xfs_reserve_blocks(mp, xfs_default_resblks(mp));
>  		if (error)
>  			xfs_warn(mp,
>  	"Unable to allocate reserve blocks. Continuing without reserve pool.");
> @@ -1053,7 +1051,6 @@ void
>  xfs_unmountfs(
>  	struct xfs_mount	*mp)
>  {
> -	uint64_t		resblks;
>  	int			error;
>  
>  	/*
> @@ -1090,8 +1087,7 @@ xfs_unmountfs(
>  	 * we only every apply deltas to the superblock and hence the incore
>  	 * value does not matter....
>  	 */
> -	resblks = 0;
> -	error = xfs_reserve_blocks(mp, &resblks, NULL);
> +	error = xfs_reserve_blocks(mp, 0);
>  	if (error)
>  		xfs_warn(mp, "Unable to free reserved block pool. "
>  				"Freespace may not be correct on next mount.");
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 764304595e8b00..d0009430a62778 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -906,10 +906,8 @@ xfs_fs_statfs(
>  STATIC void
>  xfs_save_resvblks(struct xfs_mount *mp)
>  {
> -	uint64_t resblks = 0;
> -
>  	mp->m_resblks_save = mp->m_resblks;
> -	xfs_reserve_blocks(mp, &resblks, NULL);
> +	xfs_reserve_blocks(mp, 0);
>  }
>  
>  STATIC void
> @@ -923,7 +921,7 @@ xfs_restore_resvblks(struct xfs_mount *mp)
>  	} else
>  		resblks = xfs_default_resblks(mp);
>  
> -	xfs_reserve_blocks(mp, &resblks, NULL);
> +	xfs_reserve_blocks(mp, resblks);
>  }
>  
>  /*
> -- 
> 2.39.2
> 
> 

Re: [PATCH 3/4] xfs: clean up the xfs_reserve_blocks interface

[Christoph Hellwig]

On Mon, Nov 27, 2023 at 06:09:33PM -0800, Darrick J. Wong wrote:
> > +	spin_lock(&mp->m_sb_lock);
> > +	fsop.resblks = mp->m_resblks;
> > +	fsop.resblks_avail = mp->m_resblks_avail;
> > +	spin_unlock(&mp->m_sb_lock);
> 
> Hm.  I sorta preferred keeping these details hidden in xfs_fsops.c
> rather than scattering them around and lengthening xfs_ioctl.c, but
> I think the calling convention cleanup is worthy enough for:

If you prefer I can keep a helper to fill in a xfs_fsop_resblks
structure under m_sb_lock in fsops.c, but I'm not sure that's worth it.

[PATCH 4/4] xfs: clean up xfs_fsops.h

[Christoph Hellwig]

Use struct types instead of typedefs so that the header can be included
with pulling in the headers that define the typedefs, and remove the
pointless externs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_fsops.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index 7536f8a92746f6..44457b0a059376 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -6,12 +6,12 @@
 #ifndef __XFS_FSOPS_H__
 #define	__XFS_FSOPS_H__
 
-extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
-extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
+int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
+int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
 int xfs_reserve_blocks(struct xfs_mount *mp, uint64_t request);
-extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
+int xfs_fs_goingdown(struct xfs_mount *mp, uint32_t inflags);
 
-extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
-extern int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
+int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
+int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
 
 #endif	/* __XFS_FSOPS_H__ */
-- 
2.39.2

Re: [PATCH 4/4] xfs: clean up xfs_fsops.h

[Darrick J. Wong]

On Sun, Nov 26, 2023 at 02:01:24PM +0100, Christoph Hellwig wrote:
> Use struct types instead of typedefs so that the header can be included
> with pulling in the headers that define the typedefs, and remove the
> pointless externs.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Easy review!
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_fsops.h | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
> index 7536f8a92746f6..44457b0a059376 100644
> --- a/fs/xfs/xfs_fsops.h
> +++ b/fs/xfs/xfs_fsops.h
> @@ -6,12 +6,12 @@
>  #ifndef __XFS_FSOPS_H__
>  #define	__XFS_FSOPS_H__
>  
> -extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
> -extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
> +int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
> +int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
>  int xfs_reserve_blocks(struct xfs_mount *mp, uint64_t request);
> -extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
> +int xfs_fs_goingdown(struct xfs_mount *mp, uint32_t inflags);
>  
> -extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
> -extern int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
> +int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
> +int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
>  
>  #endif	/* __XFS_FSOPS_H__ */
> -- 
> 2.39.2
> 
> 

misc cleanups to the resblks interfaces v2

[Christoph Hellwig]

Hi all,

this series has small cosmetics to the get/set reslks and fscounts
interface.

Changes since v1:
 - add a missing __user annotation
 - align the lines of a struct initialization

Diffstat:
 xfs_fsops.c |   50 +-------------------------
 xfs_fsops.h |   14 +++----
 xfs_ioctl.c |  115 ++++++++++++++++++++++++++++++++----------------------------
 xfs_mount.c |    8 +---
 xfs_super.c |    6 +--
 5 files changed, 75 insertions(+), 118 deletions(-)

[PATCH 4/4] xfs: clean up xfs_fsops.h

[Christoph Hellwig]

Use struct types instead of typedefs so that the header can be included
with pulling in the headers that define the typedefs, and remove the
pointless externs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_fsops.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index 7536f8a92746f6..44457b0a059376 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -6,12 +6,12 @@
 #ifndef __XFS_FSOPS_H__
 #define	__XFS_FSOPS_H__
 
-extern int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
-extern int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
+int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
+int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
 int xfs_reserve_blocks(struct xfs_mount *mp, uint64_t request);
-extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
+int xfs_fs_goingdown(struct xfs_mount *mp, uint32_t inflags);
 
-extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
-extern int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
+int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
+int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
 
 #endif	/* __XFS_FSOPS_H__ */
-- 
2.39.2