The patch titled
Subject: fsdax: dedup file range to use a compare function
has been added to the -mm mm-unstable branch. Its filename is
fsdax-dedup-file-range-to-use-a-compare-function.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fsdax-dedup-file-range-to-use-a-compare-function.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Subject: fsdax: dedup file range to use a compare function
Date: Fri, 3 Jun 2022 13:37:36 +0800
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@xxxxxxxxxxx
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.wiliams@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Goldwyn Rodrigues <rgoldwyn@xxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/dax.c | 82 +++++++++++++++++++++++++++++++++++++++++
fs/remap_range.c | 31 +++++++++++++--
fs/xfs/xfs_reflink.c | 8 +++-
include/linux/dax.h | 8 ++++
include/linux/fs.h | 12 ++++--
5 files changed, 130 insertions(+), 11 deletions(-)
--- a/fs/dax.c~fsdax-dedup-file-range-to-use-a-compare-function
+++ a/fs/dax.c
@@ -1873,3 +1873,85 @@ vm_fault_t dax_finish_sync_fault(struct
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);
--- a/fs/remap_range.c~fsdax-dedup-file-range-to-use-a-compare-function
+++ a/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>
@@ -271,9 +272,11 @@ out_error:
* 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)
+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 *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
if (remap_flags & REMAP_FILE_DEDUP) {
bool is_same = false;
- ret = vfs_dedupe_file_range_compare(file_in, pos_in,
- file_out, pos_out, *len, &is_same);
+ 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
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,
--- a/fs/xfs/xfs_reflink.c~fsdax-dedup-file-range-to-use-a-compare-function
+++ a/fs/xfs/xfs_reflink.c
@@ -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;
--- a/include/linux/dax.h~fsdax-dedup-file-range-to-use-a-compare-function
+++ a/include/linux/dax.h
@@ -246,6 +246,14 @@ vm_fault_t dax_finish_sync_fault(struct
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);
--- a/include/linux/fs.h~fsdax-dedup-file-range-to-use-a-compare-function
+++ a/include/linux/fs.h
@@ -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);
@@ -2072,10 +2073,13 @@ extern ssize_t vfs_copy_file_range(struc
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 *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);
_
Patches currently in -mm which might be from ruansy.fnst@xxxxxxxxxxx are
dax-introduce-holder-for-dax_device.patch
mm-factor-helpers-for-memory_failure_dev_pagemap.patch
pagemappmem-introduce-memory_failure.patch
fsdax-introduce-dax_lock_mapping_entry.patch
mm-introduce-mf_dax_kill_procs-for-fsdax-case.patch
xfs-implement-notify_failure-for-xfs.patch
fsdax-set-a-cow-flag-when-associate-reflink-mappings.patch
fsdax-output-address-in-dax_iomap_pfn-and-rename-it.patch
fsdax-introduce-dax_iomap_cow_copy.patch
fsdax-replace-mmap-entry-in-case-of-cow.patch
fsdax-add-dax_iomap_cow_copy-for-dax-zero.patch
fsdax-dedup-file-range-to-use-a-compare-function.patch
xfs-support-cow-in-fsdax-mode.patch
xfs-add-dax-dedupe-support.patch
