Commit ea6c49b7 authored by Shiyang Ruan's avatar Shiyang Ruan Committed by Andrew Morton
Browse files

xfs: support CoW in fsdax mode 

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.

[akpm@linux-foundation.org: make xfs_dax_fault() static]
Link: https://lkml.kernel.org/r/20220603053738.1218681-14-ruansy.fnst@fujitsu.com


Signed-off-by: default avatarShiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
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.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 6f7db389

fs/xfs/xfs_file.c

+28 −5
Original line number Diff line number Diff line
@@ -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

static 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

static 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);

fs/xfs/xfs_iomap.c

+29 −1
Original line number Diff line number Diff line
@@ -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)
@@ -867,6 +868,33 @@ const struct iomap_ops xfs_direct_write_iomap_ops = { 
	.iomap_begin		= xfs_direct_write_iomap_begin,

};



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,

fs/xfs/xfs_iomap.h

+1 −0
Original line number Diff line number Diff line
@@ -51,5 +51,6 @@ extern const struct iomap_ops xfs_direct_write_iomap_ops; 
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__*/