diff mbox series

[v2,08/10] fsdax: Dedup file range to use a compare function

Message ID 20210226002030.653855-9-ruansy.fnst@fujitsu.com (mailing list archive)
State New, archived
Headers show
Series fsdax,xfs: Add reflink&dedupe support for fsdax | expand

Commit Message

Shiyang Ruan Feb. 26, 2021, 12:20 a.m. UTC 
With dax we cannot deal with readpage() etc. So, we create a dax
comparison funciton which is similar with
vfs_dedupe_file_range_compare().
And introduce dax_remap_file_range_prep() for filesystem use.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 fs/dax.c             | 51 ++++++++++++++++++++++++++++++++++++++++++++
 fs/remap_range.c     | 45 +++++++++++++++++++++++++++++++-------
 fs/xfs/xfs_reflink.c |  9 ++++++--
 include/linux/dax.h  |  4 ++++
 include/linux/fs.h   | 15 +++++++++----
 5 files changed, 110 insertions(+), 14 deletions(-)

Comments

Joe Perches March 3, 2021, 8:20 a.m. UTC | #1 
On Fri, 2021-02-26 at 08:20 +0800, Shiyang Ruan wrote:
> With dax we cannot deal with readpage() etc. So, we create a dax
> comparison funciton which is similar with
> vfs_dedupe_file_range_compare().
> And introduce dax_remap_file_range_prep() for filesystem use.
[]
> diff --git a/fs/dax.c b/fs/dax.c
[]
> @@ -1856,3 +1856,54 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,l
>  	return dax_insert_pfn_mkwrite(vmf, pfn, order);
>  }
>  EXPORT_SYMBOL_GPL(dax_finish_sync_fault);
> +
> +static loff_t dax_range_compare_actor(struct inode *ino1, loff_t pos1,
> +		struct inode *ino2, loff_t pos2, loff_t len, void *data,
> +		struct iomap *smap, struct iomap *dmap)
> +{
> +	void *saddr, *daddr;
> +	bool *same = data;
> +	int ret;
> +
> +	while (len) {
> +		if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE)
> +			goto next;
> +
> +		if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) {
> +			*same = false;
> +			break;
> +		}
> +
> +		ret = dax_iomap_direct_access(smap, pos1,
> +			ALIGN(pos1 + len, PAGE_SIZE), &saddr, NULL);
> +		if (ret < 0)
> +			return -EIO;
> +
> +		ret = dax_iomap_direct_access(dmap, pos2,
> +			ALIGN(pos2 + len, PAGE_SIZE), &daddr, NULL);
> +		if (ret < 0)
> +			return -EIO;
> +
> +		*same = !memcmp(saddr, daddr, len);
> +		if (!*same)
> +			break;
> +next:
> +		len -= len;
> +	}
> +
> +	return 0;
> +}

This code looks needlessly complex.

len is never decremented inside the while loop so the while loop
itself looks unnecessary.  Is there some missing decrement of len
or some other reason to use a while loop?

Is dax_iomap_direct_access some ugly macro that modifies a hidden len?

Why not remove the while loop and use straightforward code without
unnecessary indentatation?

{
	void *saddr;
	void *daddr;
	bool *same = data;
	int ret;

	if (!len ||
	    (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE))
		return 0;

	if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) {
		*same = false;
		return 0;
	}

	ret = dax_iomap_direct_access(smap, pos1, ALIGN(pos1 + len, PAGE_SIZE),
				      &saddr, NULL);
	if (ret < 0)
		return -EIO;

	ret = dax_iomap_direct_access(dmap, pos2, ALIGN(pos2 + len, PAGE_SIZE),
				      &daddr, NULL);
	if (ret < 0)
		return -EIO;

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

	return 0;
}	

I didn't look at the rest.
diff mbox series

Patch

diff --git a/fs/dax.c b/fs/dax.c
index 4f6c6ba68e6f..bdf2b5dfee01 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1856,3 +1856,54 @@  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_actor(struct inode *ino1, loff_t pos1,
+		struct inode *ino2, loff_t pos2, loff_t len, void *data,
+		struct iomap *smap, struct iomap *dmap)
+{
+	void *saddr, *daddr;
+	bool *same = data;
+	int ret;
+
+	while (len) {
+		if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE)
+			goto next;
+
+		if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) {
+			*same = false;
+			break;
+		}
+
+		ret = dax_iomap_direct_access(smap, pos1,
+			ALIGN(pos1 + len, PAGE_SIZE), &saddr, NULL);
+		if (ret < 0)
+			return -EIO;
+
+		ret = dax_iomap_direct_access(dmap, pos2,
+			ALIGN(pos2 + len, PAGE_SIZE), &daddr, NULL);
+		if (ret < 0)
+			return -EIO;
+
+		*same = !memcmp(saddr, daddr, len);
+		if (!*same)
+			break;
+next:
+		len -= len;
+	}
+
+	return 0;
+}
+
+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 id, ret = 0;
+
+	id = dax_read_lock();
+	ret = iomap_apply2(src, srcoff, dest, destoff, len, 0, ops, is_same,
+			dax_range_compare_actor);
+	dax_read_unlock(id);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dax_dedupe_file_range_compare);
diff --git a/fs/remap_range.c b/fs/remap_range.c
index 77dba3a49e65..9079390edaf3 100644
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -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>
@@ -199,9 +200,9 @@  static void vfs_unlock_two_pages(struct page *page1, struct page *page2)
  * Compare extents of two files to see if they are the same.
  * Caller must have locked both inodes to prevent write races.
  */
-static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
-					 struct inode *dest, loff_t destoff,
-					 loff_t len, bool *is_same)
+int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
+				  struct inode *dest, loff_t destoff,
+				  loff_t len, bool *is_same)
 {
 	loff_t src_poff;
 	loff_t dest_poff;
@@ -280,6 +281,7 @@  static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
 out_error:
 	return error;
 }
+EXPORT_SYMBOL(vfs_dedupe_file_range_compare);
 
 /*
  * Check that the two inodes are eligible for cloning, the ranges make
@@ -289,9 +291,11 @@  static int vfs_dedupe_file_range_compare(struct inode *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,
-				  struct file *file_out, loff_t pos_out,
-				  loff_t *len, unsigned int remap_flags)
+static 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,
+				const struct iomap_ops *ops)
 {
 	struct inode *inode_in = file_inode(file_in);
 	struct inode *inode_out = file_inode(file_out);
@@ -351,8 +355,15 @@  int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
 	if (remap_flags & REMAP_FILE_DEDUP) {
 		bool		is_same = false;
 
-		ret = vfs_dedupe_file_range_compare(inode_in, pos_in,
-				inode_out, pos_out, *len, &is_same);
+		if (!IS_DAX(inode_in) && !IS_DAX(inode_out))
+			ret = vfs_dedupe_file_range_compare(inode_in, pos_in,
+					inode_out, pos_out, *len, &is_same);
+		else if (IS_DAX(inode_in) && IS_DAX(inode_out) && ops)
+			ret = dax_dedupe_file_range_compare(inode_in, pos_in,
+					inode_out, pos_out, *len, &is_same,
+					ops);
+		else
+			return -EINVAL;
 		if (ret)
 			return ret;
 		if (!is_same)
@@ -370,6 +381,24 @@  int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
 
 	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(dax_remap_file_range_prep);
+
+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,
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 6fa05fb78189..f5b3a3da36b7 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1308,8 +1308,13 @@  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;
 
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 3275e01ed33d..32e1c34349f2 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -239,6 +239,10 @@  int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 				      pgoff_t index);
 s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap,
 		struct iomap *srcmap);
+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);
 static inline bool dax_mapping(struct address_space *mapping)
 {
 	return mapping->host && IS_DAX(mapping->host);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fd47deea7c17..2e6ec5bdf82a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -68,6 +68,7 @@  struct fsverity_info;
 struct fsverity_operations;
 struct fs_context;
 struct fs_parameter_spec;
+struct iomap_ops;
 
 extern void __init inode_init(void);
 extern void __init inode_init_early(void);
@@ -1910,13 +1911,19 @@  extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
 				   loff_t, size_t, unsigned int);
+typedef int (*compare_range_t)(struct inode *src, loff_t srcpos,
+			       struct inode *dest, loff_t destpos,
+			       loff_t len, bool *is_same);
 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,
-					 struct file *file_out, loff_t pos_out,
-					 loff_t *count,
-					 unsigned int remap_flags);
+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);
+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);
 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);