Commit 6f7db389 authored by Shiyang Ruan's avatar Shiyang Ruan Committed by Andrew Morton
Browse files

fsdax: dedup file range to use a compare function 

With dax we cannot deal with readpage() etc.  So, we create a dax
comparison function which is similar with vfs_dedupe_file_range_compare().
And introduce dax_remap_file_range_prep() for filesystem use.

Link: https://lkml.kernel.org/r/20220603053738.1218681-13-ruansy.fnst@fujitsu.com


Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: default avatarShiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.wiliams@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8dbfc76d

fs/dax.c

+82 −0
Original line number Diff line number Diff line
@@ -1873,3 +1873,85 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 
	return dax_insert_pfn_mkwrite(vmf, pfn, order);

}

EXPORT_SYMBOL_GPL(dax_finish_sync_fault);



static loff_t dax_range_compare_iter(struct iomap_iter *it_src,

		struct iomap_iter *it_dest, u64 len, bool *same)

{

	const struct iomap *smap = &it_src->iomap;

	const struct iomap *dmap = &it_dest->iomap;

	loff_t pos1 = it_src->pos, pos2 = it_dest->pos;

	void *saddr, *daddr;

	int id, ret;



	len = min(len, min(smap->length, dmap->length));



	if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE) {

		*same = true;

		return len;

	}



	if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) {

		*same = false;

		return 0;

	}



	id = dax_read_lock();

	ret = dax_iomap_direct_access(smap, pos1, ALIGN(pos1 + len, PAGE_SIZE),

				      &saddr, NULL);

	if (ret < 0)

		goto out_unlock;



	ret = dax_iomap_direct_access(dmap, pos2, ALIGN(pos2 + len, PAGE_SIZE),

				      &daddr, NULL);

	if (ret < 0)

		goto out_unlock;



	*same = !memcmp(saddr, daddr, len);

	if (!*same)

		len = 0;

	dax_read_unlock(id);

	return len;



out_unlock:

	dax_read_unlock(id);

	return -EIO;

}



int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,

		struct inode *dst, loff_t dstoff, loff_t len, bool *same,

		const struct iomap_ops *ops)

{

	struct iomap_iter src_iter = {

		.inode		= src,

		.pos		= srcoff,

		.len		= len,

		.flags		= IOMAP_DAX,

	};

	struct iomap_iter dst_iter = {

		.inode		= dst,

		.pos		= dstoff,

		.len		= len,

		.flags		= IOMAP_DAX,

	};

	int ret;



	while ((ret = iomap_iter(&src_iter, ops)) > 0) {

		while ((ret = iomap_iter(&dst_iter, ops)) > 0) {

			dst_iter.processed = dax_range_compare_iter(&src_iter,

						&dst_iter, len, same);

		}

		if (ret <= 0)

			src_iter.processed = ret;

	}

	return ret;

}



int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,

			      struct file *file_out, loff_t pos_out,

			      loff_t *len, unsigned int remap_flags,

			      const struct iomap_ops *ops)

{

	return __generic_remap_file_range_prep(file_in, pos_in, file_out,

					       pos_out, len, remap_flags, ops);

}

EXPORT_SYMBOL_GPL(dax_remap_file_range_prep);

fs/remap_range.c

+26 −5
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/compat.h>

#include <linux/mount.h>

#include <linux/fs.h>

#include <linux/dax.h>

#include "internal.h"



#include <linux/uaccess.h>
@@ -271,9 +272,11 @@ static int vfs_dedupe_file_range_compare(struct file *src, loff_t srcoff, 
 * If there's an error, then the usual negative error code is returned.

 * Otherwise returns 0 with *len set to the request length.

 */

int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,

int

__generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,

				struct file *file_out, loff_t pos_out,

				  loff_t *len, unsigned int remap_flags)

				loff_t *len, unsigned int remap_flags,

				const struct iomap_ops *dax_read_ops)

{

	struct inode *inode_in = file_inode(file_in);

	struct inode *inode_out = file_inode(file_out);
@@ -333,8 +336,18 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, 
	if (remap_flags & REMAP_FILE_DEDUP) {

		bool		is_same = false;



		if (*len == 0)

			return 0;



		if (!IS_DAX(inode_in))

			ret = vfs_dedupe_file_range_compare(file_in, pos_in,

					file_out, pos_out, *len, &is_same);

		else if (dax_read_ops)

			ret = dax_dedupe_file_range_compare(inode_in, pos_in,

					inode_out, pos_out, *len, &is_same,

					dax_read_ops);

		else

			return -EINVAL;

		if (ret)

			return ret;

		if (!is_same)
@@ -352,6 +365,14 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, 


	return ret;

}



int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,

				  struct file *file_out, loff_t pos_out,

				  loff_t *len, unsigned int remap_flags)

{

	return __generic_remap_file_range_prep(file_in, pos_in, file_out,

					       pos_out, len, remap_flags, NULL);

}

EXPORT_SYMBOL(generic_remap_file_range_prep);



loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,

fs/xfs/xfs_reflink.c

+6 −2
Original line number Diff line number Diff line
@@ -1367,8 +1367,12 @@ xfs_reflink_remap_prep( 
	if (IS_DAX(inode_in) || IS_DAX(inode_out))

		goto out_unlock;



	ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,

			len, remap_flags);

	if (!IS_DAX(inode_in))

		ret = generic_remap_file_range_prep(file_in, pos_in, file_out,

				pos_out, len, remap_flags);

	else

		ret = dax_remap_file_range_prep(file_in, pos_in, file_out,

				pos_out, len, remap_flags, &xfs_read_iomap_ops);

	if (ret || *len == 0)

		goto out_unlock;

include/linux/dax.h

+8 −0
Original line number Diff line number Diff line
@@ -246,6 +246,14 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);

int dax_invalidate_mapping_entry_sync(struct address_space *mapping,

				      pgoff_t index);

int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,

				  struct inode *dest, loff_t destoff,

				  loff_t len, bool *is_same,

				  const struct iomap_ops *ops);

int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,

			      struct file *file_out, loff_t pos_out,

			      loff_t *len, unsigned int remap_flags,

			      const struct iomap_ops *ops);

static inline bool dax_mapping(struct address_space *mapping)

{

	return mapping->host && IS_DAX(mapping->host);

include/linux/fs.h

+8 −4
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ struct fsverity_operations; 
struct fs_context;

struct fs_parameter_spec;

struct fileattr;

struct iomap_ops;



extern void __init inode_init(void);

extern void __init inode_init_early(void);
@@ -2070,10 +2071,13 @@ extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, 
extern ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in,

				       struct file *file_out, loff_t pos_out,

				       size_t len, unsigned int flags);

extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,

int __generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,

				    struct file *file_out, loff_t pos_out,

					 loff_t *count,

					 unsigned int remap_flags);

				    loff_t *len, unsigned int remap_flags,

				    const struct iomap_ops *dax_read_ops);

int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,

				  struct file *file_out, loff_t pos_out,

				  loff_t *count, unsigned int remap_flags);

extern loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,

				  struct file *file_out, loff_t pos_out,

				  loff_t len, unsigned int remap_flags);