[PATCH 0/3 V3] xfs: allow logical-sector sized O_DIRECT for any fs sector size

[PATCH 0/3 V3] xfs: allow logical-sector sized O_DIRECT for any fs sector size

[Eric Sandeen]

Ok once more with feeling.

Patchset to allow sub-fs-metadata-sector-sized DIOs.

I have (still) explicitly not changed XFS_IOC_DIOINFO output for now;
it still reports the actual minimum sizes and alignments which will
be allowed by the filesystem (and block layer beneath it).

Thanks,
-Eric

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[PATCH 1/3 V3] xfs: clean up xfs_buftarg

[Eric Sandeen]

Clean up the xfs_buftarg structure a bit:
- remove bt_bsize which is never used
- replace bt_sshift with bt_ssize; we only ever shift it back

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

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 9fccfb5..b664bce 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -445,7 +445,7 @@ _xfs_buf_find(
 	numbytes = BBTOB(numblks);
 
 	/* Check for IOs smaller than the sector size / not sector aligned */
-	ASSERT(!(numbytes < (1 << btp->bt_sshift)));
+	ASSERT(!(numbytes < btp->bt_ssize));
 	ASSERT(!(BBTOB(blkno) & (xfs_off_t)btp->bt_smask));
 
 	/*
@@ -1599,8 +1599,7 @@ xfs_setsize_buftarg(
 	unsigned int		blocksize,
 	unsigned int		sectorsize)
 {
-	btp->bt_bsize = blocksize;
-	btp->bt_sshift = ffs(sectorsize) - 1;
+	btp->bt_ssize = sectorsize;
 	btp->bt_smask = sectorsize - 1;
 
 	if (set_blocksize(btp->bt_bdev, sectorsize)) {
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 1cf21a4..4ef949a 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -93,8 +93,7 @@ typedef struct xfs_buftarg {
 	struct block_device	*bt_bdev;
 	struct backing_dev_info	*bt_bdi;
 	struct xfs_mount	*bt_mount;
-	unsigned int		bt_bsize;
-	unsigned int		bt_sshift;
+	unsigned int		bt_ssize;
 	size_t			bt_smask;
 
 	/* LRU control structures */
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 33ad9a7..39c38ee 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1587,7 +1587,7 @@ xfs_file_ioctl(
 			XFS_IS_REALTIME_INODE(ip) ?
 			mp->m_rtdev_targp : mp->m_ddev_targp;
 
-		da.d_mem = da.d_miniosz = 1 << target->bt_sshift;
+		da.d_mem = da.d_miniosz = target->bt_ssize;
 		da.d_maxiosz = INT_MAX & ~(da.d_miniosz - 1);
 
 		if (copy_to_user(arg, &da, sizeof(da)))

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Re: [PATCH 1/3 V3] xfs: clean up xfs_buftarg

[Dave Chinner]

On Tue, Jan 21, 2014 at 04:44:57PM -0600, Eric Sandeen wrote:
> Clean up the xfs_buftarg structure a bit:
> - remove bt_bsize which is never used
> - replace bt_sshift with bt_ssize; we only ever shift it back
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Looks good.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com

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[PATCH 2/3 V3] xfs: rename xfs_buftarg structure members

[Eric Sandeen]

In preparation for adding new members to the structure,
give these old ones more descriptive names:

	bt_ssize -> bt_meta_sectorsize
	bt_smask -> bt_meta_sectormask

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

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index b664bce..a526f8d 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -445,8 +445,8 @@ _xfs_buf_find(
 	numbytes = BBTOB(numblks);
 
 	/* Check for IOs smaller than the sector size / not sector aligned */
-	ASSERT(!(numbytes < btp->bt_ssize));
-	ASSERT(!(BBTOB(blkno) & (xfs_off_t)btp->bt_smask));
+	ASSERT(!(numbytes < btp->bt_meta_sectorsize));
+	ASSERT(!(BBTOB(blkno) & (xfs_off_t)btp->bt_meta_sectormask));
 
 	/*
 	 * Corrupted block numbers can get through to here, unfortunately, so we
@@ -1599,8 +1599,8 @@ xfs_setsize_buftarg(
 	unsigned int		blocksize,
 	unsigned int		sectorsize)
 {
-	btp->bt_ssize = sectorsize;
-	btp->bt_smask = sectorsize - 1;
+	btp->bt_meta_sectorsize = sectorsize;
+	btp->bt_meta_sectormask = sectorsize - 1;
 
 	if (set_blocksize(btp->bt_bdev, sectorsize)) {
 		char name[BDEVNAME_SIZE];
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 4ef949a..d5d88dd 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -93,8 +93,8 @@ typedef struct xfs_buftarg {
 	struct block_device	*bt_bdev;
 	struct backing_dev_info	*bt_bdi;
 	struct xfs_mount	*bt_mount;
-	unsigned int		bt_ssize;
-	size_t			bt_smask;
+	unsigned int		bt_meta_sectorsize;
+	size_t			bt_meta_sectormask;
 
 	/* LRU control structures */
 	struct shrinker		bt_shrinker;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 52c91e1..ef0c933 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -261,7 +261,7 @@ xfs_file_aio_read(
 		xfs_buftarg_t	*target =
 			XFS_IS_REALTIME_INODE(ip) ?
 				mp->m_rtdev_targp : mp->m_ddev_targp;
-		if ((pos & target->bt_smask) || (size & target->bt_smask)) {
+		if ((pos | size) & target->bt_meta_sectormask) {
 			if (pos == i_size_read(inode))
 				return 0;
 			return -XFS_ERROR(EINVAL);
@@ -641,7 +641,7 @@ xfs_file_dio_aio_write(
 	struct xfs_buftarg	*target = XFS_IS_REALTIME_INODE(ip) ?
 					mp->m_rtdev_targp : mp->m_ddev_targp;
 
-	if ((pos & target->bt_smask) || (count & target->bt_smask))
+	if ((pos | count) & target->bt_meta_sectormask)
 		return -XFS_ERROR(EINVAL);
 
 	if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 39c38ee..64ca8e9 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1587,7 +1587,7 @@ xfs_file_ioctl(
 			XFS_IS_REALTIME_INODE(ip) ?
 			mp->m_rtdev_targp : mp->m_ddev_targp;
 
-		da.d_mem = da.d_miniosz = target->bt_ssize;
+		da.d_mem = da.d_miniosz = target->bt_meta_sectorsize;
 		da.d_maxiosz = INT_MAX & ~(da.d_miniosz - 1);
 
 		if (copy_to_user(arg, &da, sizeof(da)))


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Re: [PATCH 2/3 V3] xfs: rename xfs_buftarg structure members

[Dave Chinner]

On Tue, Jan 21, 2014 at 04:45:52PM -0600, Eric Sandeen wrote:
> In preparation for adding new members to the structure,
> give these old ones more descriptive names:
> 
> 	bt_ssize -> bt_meta_sectorsize
> 	bt_smask -> bt_meta_sectormask
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

looks good. Thanks for renaming these ;)

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com

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[PATCH 3/3 V3] xfs: allow logical-sector sized O_DIRECT

[Eric Sandeen]

Some time ago, mkfs.xfs started picking the storage physical
sector size as the default filesystem "sector size" in order
to avoid RMW costs incurred by doing IOs at logical sector
size alignments.

However, this means that for a filesystem made with i.e.
a 4k sector size on an "advanced format" 4k/512 disk,
512-byte direct IOs are no longer allowed.  This means
that XFS has essentially turned this AF drive into a hard
4K device, from the filesystem on up.

XFS's mkfs-specified "sector size" is really just controlling
the minimum size & alignment of filesystem metadata.

There is no real need to tightly couple XFS's minimal
metadata size to the minimum allowed direct IO size;
XFS can continue doing metadata in optimal sizes, but
still allow smaller DIOs for apps which issue them,
for whatever reason.

This patch adds a new field to the xfs_buftarg, so that
we now track 2 sizes:

 1) The metadata sector size, which is the minimum unit and
    alignment of IO which will be performed by metadata operations.
 2) The device logical sector size

The first is used internally by the file system for metadata
alignment and IOs.
The second is used for the minimum allowed direct IO alignment.

This has passed xfstests on filesystems made with 4k sectors,
including when run under the patch I sent to ignore
XFS_IOC_DIOINFO, and issue 512 DIOs anyway.  I also directly
tested end of block behavior on preallocated, sparse, and
existing files when we do a 512 IO into a 4k file on a 
4k-sector filesystem, to be sure there were no unexpected
behaviors.

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

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index a526f8d..5175711 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1599,6 +1599,7 @@ xfs_setsize_buftarg(
 	unsigned int		blocksize,
 	unsigned int		sectorsize)
 {
+	/* Set up metadata sector size info */
 	btp->bt_meta_sectorsize = sectorsize;
 	btp->bt_meta_sectormask = sectorsize - 1;
 
@@ -1613,6 +1614,10 @@ xfs_setsize_buftarg(
 		return EINVAL;
 	}
 
+	/* Set up device logical sector size mask */
+	btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev);
+	btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1;
+
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index d5d88dd..9953395 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -88,6 +88,19 @@ typedef unsigned int xfs_buf_flags_t;
  */
 #define XFS_BSTATE_DISPOSE	 (1 << 0)	/* buffer being discarded */
 
+/*
+ * The xfs_buftarg contains 2 notions of "sector size" -
+ *
+ * 1) The metadata sector size, which is the minimum unit and
+ *    alignment of IO which will be performed by metadata operations.
+ * 2) The device logical sector size
+ *
+ * The first is specified at mkfs time, and is stored on-disk in the
+ * superblock's sb_sectsize.
+ *
+ * The latter is derived from the underlying device, and controls direct IO
+ * alignment constraints.
+ */
 typedef struct xfs_buftarg {
 	dev_t			bt_dev;
 	struct block_device	*bt_bdev;
@@ -95,6 +108,8 @@ typedef struct xfs_buftarg {
 	struct xfs_mount	*bt_mount;
 	unsigned int		bt_meta_sectorsize;
 	size_t			bt_meta_sectormask;
+	size_t			bt_logical_sectorsize;
+	size_t			bt_logical_sectormask;
 
 	/* LRU control structures */
 	struct shrinker		bt_shrinker;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index ef0c933..57725b4 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -261,7 +261,8 @@ xfs_file_aio_read(
 		xfs_buftarg_t	*target =
 			XFS_IS_REALTIME_INODE(ip) ?
 				mp->m_rtdev_targp : mp->m_ddev_targp;
-		if ((pos | size) & target->bt_meta_sectormask) {
+		/* DIO must be aligned to device logical sector size */
+		if ((pos | size) & target->bt_logical_sectormask) {
 			if (pos == i_size_read(inode))
 				return 0;
 			return -XFS_ERROR(EINVAL);
@@ -641,9 +642,11 @@ xfs_file_dio_aio_write(
 	struct xfs_buftarg	*target = XFS_IS_REALTIME_INODE(ip) ?
 					mp->m_rtdev_targp : mp->m_ddev_targp;
 
-	if ((pos | count) & target->bt_meta_sectormask)
+	/* DIO must be aligned to device logical sector size */
+	if ((pos | count) & target->bt_logical_sectormask)
 		return -XFS_ERROR(EINVAL);
 
+	/* "unaligned" here means not aligned to a filesystem block */
 	if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
 		unaligned_io = 1;
 
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 64ca8e9..f7ac335 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1587,7 +1587,7 @@ xfs_file_ioctl(
 			XFS_IS_REALTIME_INODE(ip) ?
 			mp->m_rtdev_targp : mp->m_ddev_targp;
 
-		da.d_mem = da.d_miniosz = target->bt_meta_sectorsize;
+		da.d_mem =  da.d_miniosz = target->bt_logical_sectorsize;
 		da.d_maxiosz = INT_MAX & ~(da.d_miniosz - 1);
 
 		if (copy_to_user(arg, &da, sizeof(da)))

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Re: [PATCH 3/3 V3] xfs: allow logical-sector sized O_DIRECT

[Brian Foster]

On 01/21/2014 05:46 PM, Eric Sandeen wrote:
> Some time ago, mkfs.xfs started picking the storage physical
> sector size as the default filesystem "sector size" in order
> to avoid RMW costs incurred by doing IOs at logical sector
> size alignments.
> 
> However, this means that for a filesystem made with i.e.
> a 4k sector size on an "advanced format" 4k/512 disk,
> 512-byte direct IOs are no longer allowed.  This means
> that XFS has essentially turned this AF drive into a hard
> 4K device, from the filesystem on up.
> 
> XFS's mkfs-specified "sector size" is really just controlling
> the minimum size & alignment of filesystem metadata.
> 
> There is no real need to tightly couple XFS's minimal
> metadata size to the minimum allowed direct IO size;
> XFS can continue doing metadata in optimal sizes, but
> still allow smaller DIOs for apps which issue them,
> for whatever reason.
> 
> This patch adds a new field to the xfs_buftarg, so that
> we now track 2 sizes:
> 
>  1) The metadata sector size, which is the minimum unit and
>     alignment of IO which will be performed by metadata operations.
>  2) The device logical sector size
> 
> The first is used internally by the file system for metadata
> alignment and IOs.
> The second is used for the minimum allowed direct IO alignment.
> 
> This has passed xfstests on filesystems made with 4k sectors,
> including when run under the patch I sent to ignore
> XFS_IOC_DIOINFO, and issue 512 DIOs anyway.  I also directly
> tested end of block behavior on preallocated, sparse, and
> existing files when we do a 512 IO into a 4k file on a 
> 4k-sector filesystem, to be sure there were no unexpected
> behaviors.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---

Looks good to me...

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

> 
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index a526f8d..5175711 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1599,6 +1599,7 @@ xfs_setsize_buftarg(
>  	unsigned int		blocksize,
>  	unsigned int		sectorsize)
>  {
> +	/* Set up metadata sector size info */
>  	btp->bt_meta_sectorsize = sectorsize;
>  	btp->bt_meta_sectormask = sectorsize - 1;
>  
> @@ -1613,6 +1614,10 @@ xfs_setsize_buftarg(
>  		return EINVAL;
>  	}
>  
> +	/* Set up device logical sector size mask */
> +	btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev);
> +	btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1;
> +
>  	return 0;
>  }
>  
> diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
> index d5d88dd..9953395 100644
> --- a/fs/xfs/xfs_buf.h
> +++ b/fs/xfs/xfs_buf.h
> @@ -88,6 +88,19 @@ typedef unsigned int xfs_buf_flags_t;
>   */
>  #define XFS_BSTATE_DISPOSE	 (1 << 0)	/* buffer being discarded */
>  
> +/*
> + * The xfs_buftarg contains 2 notions of "sector size" -
> + *
> + * 1) The metadata sector size, which is the minimum unit and
> + *    alignment of IO which will be performed by metadata operations.
> + * 2) The device logical sector size
> + *
> + * The first is specified at mkfs time, and is stored on-disk in the
> + * superblock's sb_sectsize.
> + *
> + * The latter is derived from the underlying device, and controls direct IO
> + * alignment constraints.
> + */
>  typedef struct xfs_buftarg {
>  	dev_t			bt_dev;
>  	struct block_device	*bt_bdev;
> @@ -95,6 +108,8 @@ typedef struct xfs_buftarg {
>  	struct xfs_mount	*bt_mount;
>  	unsigned int		bt_meta_sectorsize;
>  	size_t			bt_meta_sectormask;
> +	size_t			bt_logical_sectorsize;
> +	size_t			bt_logical_sectormask;
>  
>  	/* LRU control structures */
>  	struct shrinker		bt_shrinker;
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index ef0c933..57725b4 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -261,7 +261,8 @@ xfs_file_aio_read(
>  		xfs_buftarg_t	*target =
>  			XFS_IS_REALTIME_INODE(ip) ?
>  				mp->m_rtdev_targp : mp->m_ddev_targp;
> -		if ((pos | size) & target->bt_meta_sectormask) {
> +		/* DIO must be aligned to device logical sector size */
> +		if ((pos | size) & target->bt_logical_sectormask) {
>  			if (pos == i_size_read(inode))
>  				return 0;
>  			return -XFS_ERROR(EINVAL);
> @@ -641,9 +642,11 @@ xfs_file_dio_aio_write(
>  	struct xfs_buftarg	*target = XFS_IS_REALTIME_INODE(ip) ?
>  					mp->m_rtdev_targp : mp->m_ddev_targp;
>  
> -	if ((pos | count) & target->bt_meta_sectormask)
> +	/* DIO must be aligned to device logical sector size */
> +	if ((pos | count) & target->bt_logical_sectormask)
>  		return -XFS_ERROR(EINVAL);
>  
> +	/* "unaligned" here means not aligned to a filesystem block */
>  	if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
>  		unaligned_io = 1;
>  
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 64ca8e9..f7ac335 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1587,7 +1587,7 @@ xfs_file_ioctl(
>  			XFS_IS_REALTIME_INODE(ip) ?
>  			mp->m_rtdev_targp : mp->m_ddev_targp;
>  
> -		da.d_mem = da.d_miniosz = target->bt_meta_sectorsize;
> +		da.d_mem =  da.d_miniosz = target->bt_logical_sectorsize;
>  		da.d_maxiosz = INT_MAX & ~(da.d_miniosz - 1);
>  
>  		if (copy_to_user(arg, &da, sizeof(da)))
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
> 

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Re: [PATCH 3/3 V3] xfs: allow logical-sector sized O_DIRECT

[Dave Chinner]

On Tue, Jan 21, 2014 at 04:46:23PM -0600, Eric Sandeen wrote:
> Some time ago, mkfs.xfs started picking the storage physical
> sector size as the default filesystem "sector size" in order
> to avoid RMW costs incurred by doing IOs at logical sector
> size alignments.
> 
> However, this means that for a filesystem made with i.e.
> a 4k sector size on an "advanced format" 4k/512 disk,
> 512-byte direct IOs are no longer allowed.  This means
> that XFS has essentially turned this AF drive into a hard
> 4K device, from the filesystem on up.
> 
> XFS's mkfs-specified "sector size" is really just controlling
> the minimum size & alignment of filesystem metadata.
> 
> There is no real need to tightly couple XFS's minimal
> metadata size to the minimum allowed direct IO size;
> XFS can continue doing metadata in optimal sizes, but
> still allow smaller DIOs for apps which issue them,
> for whatever reason.
> 
> This patch adds a new field to the xfs_buftarg, so that
> we now track 2 sizes:
> 
>  1) The metadata sector size, which is the minimum unit and
>     alignment of IO which will be performed by metadata operations.
>  2) The device logical sector size
> 
> The first is used internally by the file system for metadata
> alignment and IOs.
> The second is used for the minimum allowed direct IO alignment.
> 
> This has passed xfstests on filesystems made with 4k sectors,
> including when run under the patch I sent to ignore
> XFS_IOC_DIOINFO, and issue 512 DIOs anyway.  I also directly
> tested end of block behavior on preallocated, sparse, and
> existing files when we do a 512 IO into a 4k file on a 
> 4k-sector filesystem, to be sure there were no unexpected
> behaviors.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Looks good. Nice work with the comments.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com

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