The patch titled
Subject: xfs: support CoW in fsdax mode
has been added to the -mm mm-unstable branch. Its filename is
xfs-support-cow-in-fsdax-mode.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/xfs-support-cow-in-fsdax-mode.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: xfs: support CoW in fsdax mode
Date: Fri, 3 Jun 2022 13:37:37 +0800
In fsdax mode, WRITE and ZERO on a shared extent need CoW performed.
After that, new allocated extents needs to be remapped to the file. So,
add a CoW identification in ->iomap_begin(), and implement ->iomap_end()
to do the remapping work.
Link: https://lkml.kernel.org/r/20220603053738.1218681-14-ruansy.fnst@xxxxxxxxxxx
Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dan Williams <dan.j.wiliams@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
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/xfs/xfs_file.c | 33 ++++++++++++++++++++++++++++-----
fs/xfs/xfs_iomap.c | 30 +++++++++++++++++++++++++++++-
fs/xfs/xfs_iomap.h | 1 +
3 files changed, 58 insertions(+), 6 deletions(-)
--- a/fs/xfs/xfs_file.c~xfs-support-cow-in-fsdax-mode
+++ a/fs/xfs/xfs_file.c
@@ -25,6 +25,7 @@
#include "xfs_iomap.h"
#include "xfs_reflink.h"
+#include <linux/dax.h>
#include <linux/falloc.h>
#include <linux/backing-dev.h>
#include <linux/mman.h>
@@ -669,7 +670,7 @@ xfs_file_dax_write(
pos = iocb->ki_pos;
trace_xfs_file_dax_write(iocb, from);
- ret = dax_iomap_rw(iocb, from, &xfs_direct_write_iomap_ops);
+ ret = dax_iomap_rw(iocb, from, &xfs_dax_write_iomap_ops);
if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
i_size_write(inode, iocb->ki_pos);
error = xfs_setfilesize(ip, pos, ret);
@@ -1254,6 +1255,31 @@ xfs_file_llseek(
return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
}
+#ifdef CONFIG_FS_DAX
+int
+xfs_dax_fault(
+ struct vm_fault *vmf,
+ enum page_entry_size pe_size,
+ bool write_fault,
+ pfn_t *pfn)
+{
+ return dax_iomap_fault(vmf, pe_size, pfn, NULL,
+ (write_fault && !vmf->cow_page) ?
+ &xfs_dax_write_iomap_ops :
+ &xfs_read_iomap_ops);
+}
+#else
+int
+xfs_dax_fault(
+ struct vm_fault *vmf,
+ enum page_entry_size pe_size,
+ bool write_fault,
+ pfn_t *pfn)
+{
+ return 0;
+}
+#endif
+
/*
* Locking for serialisation of IO during page faults. This results in a lock
* ordering of:
@@ -1285,10 +1311,7 @@ __xfs_filemap_fault(
pfn_t pfn;
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
- ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL,
- (write_fault && !vmf->cow_page) ?
- &xfs_direct_write_iomap_ops :
- &xfs_read_iomap_ops);
+ ret = xfs_dax_fault(vmf, pe_size, write_fault, &pfn);
if (ret & VM_FAULT_NEEDDSYNC)
ret = dax_finish_sync_fault(vmf, pe_size, pfn);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
--- a/fs/xfs/xfs_iomap.c~xfs-support-cow-in-fsdax-mode
+++ a/fs/xfs/xfs_iomap.c
@@ -773,7 +773,8 @@ xfs_direct_write_iomap_begin(
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
- &lockmode, flags & IOMAP_DIRECT);
+ &lockmode,
+ (flags & IOMAP_DIRECT) || IS_DAX(inode));
if (error)
goto out_unlock;
if (shared)
@@ -868,6 +869,33 @@ const struct iomap_ops xfs_direct_write_
};
static int
+xfs_dax_write_iomap_end(
+ struct inode *inode,
+ loff_t pos,
+ loff_t length,
+ ssize_t written,
+ unsigned flags,
+ struct iomap *iomap)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+
+ if (!xfs_is_cow_inode(ip))
+ return 0;
+
+ if (!written) {
+ xfs_reflink_cancel_cow_range(ip, pos, length, true);
+ return 0;
+ }
+
+ return xfs_reflink_end_cow(ip, pos, written);
+}
+
+const struct iomap_ops xfs_dax_write_iomap_ops = {
+ .iomap_begin = xfs_direct_write_iomap_begin,
+ .iomap_end = xfs_dax_write_iomap_end,
+};
+
+static int
xfs_buffered_write_iomap_begin(
struct inode *inode,
loff_t offset,
--- a/fs/xfs/xfs_iomap.h~xfs-support-cow-in-fsdax-mode
+++ a/fs/xfs/xfs_iomap.h
@@ -51,5 +51,6 @@ extern const struct iomap_ops xfs_direct
extern const struct iomap_ops xfs_read_iomap_ops;
extern const struct iomap_ops xfs_seek_iomap_ops;
extern const struct iomap_ops xfs_xattr_iomap_ops;
+extern const struct iomap_ops xfs_dax_write_iomap_ops;
#endif /* __XFS_IOMAP_H__*/
_
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
