DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B04F23954
Subject: Re: [f2fs-dev] [PATCH v3] f2fs: dax: implement direct access
To: sunqiuyang <sunqiuyang@huawei.com>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
References: <1496827763-575-1-git-send-email-sunqiuyang@huawei.com>
From: Chao Yu <chao@kernel.org>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Message-ID: <327fe770-dc35-2158-a032-c270f10b264f@kernel.org>
Date: Wed, 7 Jun 2017 23:42:27 +0800
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Hi Qiuyang,

On 2017/6/7 17:29, sunqiuyang wrote:
> From: Qiuyang Sun <sunqiuyang@huawei.com>
> 
> This is a new version of PATCH v2 2/2 with the following minor changes:
> - In dax_move_data_page(), the call of allocate_data_block() is changed
>   according to the new definition of this function in f2fs-dev, and the 
>   usage of wio_mutex is removed;
> - put_dax() is added in f2fs_iomap_end().
> 
> Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
> ---
>  fs/f2fs/data.c   |  93 ++++++++++++++++++++++++++
>  fs/f2fs/f2fs.h   |   8 +++
>  fs/f2fs/file.c   | 194 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  fs/f2fs/gc.c     |  93 ++++++++++++++++++++++++--
>  fs/f2fs/inline.c |   4 ++
>  fs/f2fs/namei.c  |   6 ++
>  fs/f2fs/super.c  |  15 +++++
>  7 files changed, 407 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 7d3af48..2285a10 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2257,3 +2257,96 @@ int f2fs_migrate_page(struct address_space *mapping,
>  	.migratepage    = f2fs_migrate_page,
>  #endif
>  };
> +
> +#ifdef CONFIG_FS_DAX
> +#include <linux/iomap.h>
> +#include <linux/dax.h>
> +
> +static int f2fs_iomap_begin(struct inode *inode, loff_t offset,
> +	loff_t length, unsigned int flags, struct iomap *iomap)
> +{
> +	struct block_device *bdev;
> +	unsigned long first_block = F2FS_BYTES_TO_BLK(offset);
> +	unsigned long last_block = F2FS_BYTES_TO_BLK(offset + length - 1);
> +	struct f2fs_map_blocks map;
> +	int ret;
> +	loff_t original_i_size = i_size_read(inode);
> +
> +	if (WARN_ON_ONCE(f2fs_has_inline_data(inode)))
> +		return -ERANGE;
> +
> +	map.m_lblk = first_block;
> +	map.m_len = last_block - first_block + 1;
> +	map.m_next_pgofs = NULL;
> +
> +	if (!(flags & IOMAP_WRITE))
> +		ret = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_READ);
> +	else {
> +		ret = f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_DIO);
> +	/* i_size should be kept here and changed later in f2fs_iomap_end */
> +		if (i_size_read(inode) != original_i_size)
> +			f2fs_i_size_write(inode, original_i_size);

If we allocated partial blocks in f2fs_map_blocks, then failed to
allocate left ones due to ENOSPC or ENOMEM..., it needs to do the
truncation according to original i_size.

> +	}
> +
> +	if (ret)
> +		return ret;
> +
> +	iomap->flags = 0;
> +	bdev = inode->i_sb->s_bdev;
> +	iomap->bdev = bdev;
> +	if (blk_queue_dax(bdev->bd_queue))
> +		iomap->dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
> +	else
> +		iomap->dax_dev = NULL;
> +	iomap->offset = F2FS_BLK_TO_BYTES((u64)first_block);
> +
> +	if (map.m_len == 0) {
> +		iomap->type = IOMAP_HOLE;
> +		iomap->blkno = IOMAP_NULL_BLOCK;
> +		iomap->length = F2FS_BLKSIZE;
> +	} else {
> +		if (map.m_flags & F2FS_MAP_MAPPED) {
> +			iomap->type = IOMAP_MAPPED;
> +		} else if (map.m_flags & F2FS_MAP_UNWRITTEN) {
> +			iomap->type = IOMAP_UNWRITTEN;

For read path, if blkaddr loaded in dnode is NEW_ADDR, we will set both
F2FS_MAP_MAPPED and F2FS_MAP_UNWRITTEN flag in m_flags. With above
condition we will set IOMAP_MAPPED instead of IOMAP_UNWRITTEN which may
result in incorrectly using of map.m_pblk. So how about reverse above
judgment condition to correct it?

> +		} else {
> +			WARN_ON_ONCE(1);
> +			return -EIO;
> +		}
> +		iomap->blkno =
> +			(sector_t)map.m_pblk << F2FS_LOG_SECTORS_PER_BLOCK;
> +		iomap->length = F2FS_BLK_TO_BYTES((u64)map.m_len);
> +	}
> +
> +	if (map.m_flags & F2FS_MAP_NEW)
> +		iomap->flags |= IOMAP_F_NEW;
> +	return 0;
> +}
> +
> +static int f2fs_iomap_end(struct inode *inode, loff_t offset, loff_t length,
> +	ssize_t written, unsigned int flags, struct iomap *iomap)
> +{
> +	put_dax(iomap->dax_dev);

Why should we use dax_get_by_host & put_dax here?

> +	if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT))
> +		return 0;
> +
> +	if (offset + written > i_size_read(inode))
> +		f2fs_i_size_write(inode, offset + written);
> +
> +	if (iomap->offset + iomap->length >
> +			ALIGN(i_size_read(inode), F2FS_BLKSIZE)) {
> +		block_t written_blk = F2FS_BYTES_TO_BLK(offset + written);
> +		block_t end_blk = F2FS_BYTES_TO_BLK(offset + length);
> +
> +		if (written_blk < end_blk)
> +			f2fs_write_failed(inode->i_mapping, offset + length);
> +	}

f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);

> +
> +	return 0;
> +}
> +
> +struct iomap_ops f2fs_iomap_ops = {
> +	.iomap_begin	= f2fs_iomap_begin,
> +	.iomap_end	= f2fs_iomap_end,
> +};
> +#endif
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index da70964..e3c2ed4 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -88,6 +88,11 @@ struct f2fs_fault_info {
>  #define F2FS_MOUNT_FAULT_INJECTION	0x00010000
>  #define F2FS_MOUNT_ADAPTIVE		0x00020000
>  #define F2FS_MOUNT_LFS			0x00040000
> +#ifdef CONFIG_FS_DAX
> +#define F2FS_MOUNT_DAX			0x00080000 /* Direct Access */
> +#else
> +#define F2FS_MOUNT_DAX			0
> +#endif
>  
>  #define clear_opt(sbi, option)	((sbi)->mount_opt.opt &= ~F2FS_MOUNT_##option)
>  #define set_opt(sbi, option)	((sbi)->mount_opt.opt |= F2FS_MOUNT_##option)
> @@ -2387,6 +2392,9 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
>  int f2fs_migrate_page(struct address_space *mapping, struct page *newpage,
>  			struct page *page, enum migrate_mode mode);
>  #endif
> +#ifdef CONFIG_FS_DAX
> +extern struct iomap_ops f2fs_iomap_ops;
> +#endif
>  
>  /*
>   * gc.c
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index ac8b943..4b070b0 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -23,6 +23,8 @@
>  #include <linux/uio.h>
>  #include <linux/uuid.h>
>  #include <linux/file.h>
> +#include <linux/dax.h>
> +#include <linux/iomap.h>
>  
>  #include "f2fs.h"
>  #include "node.h"
> @@ -121,6 +123,64 @@ static int f2fs_vm_page_mkwrite(struct vm_fault *vmf)
>  	.page_mkwrite	= f2fs_vm_page_mkwrite,
>  };
>  
> +#ifdef CONFIG_FS_DAX
> +static int f2fs_dax_huge_fault(struct vm_fault *vmf,
> +	enum page_entry_size pe_size)
> +{
> +	int result;
> +	struct inode *inode = file_inode(vmf->vma->vm_file);
> +	struct super_block *sb = inode->i_sb;
> +	bool write = vmf->flags & FAULT_FLAG_WRITE;
> +
> +	if (write) {
> +		sb_start_pagefault(sb);
> +		file_update_time(vmf->vma->vm_file);
> +	}
> +	down_read(&F2FS_I(inode)->i_mmap_sem);
> +	result = dax_iomap_fault(vmf, pe_size, &f2fs_iomap_ops);
> +	up_read(&F2FS_I(inode)->i_mmap_sem);
> +	if (write)
> +		sb_end_pagefault(sb);
> +
> +	return result;
> +}
> +
> +static int f2fs_dax_fault(struct vm_fault *vmf)
> +{
> +	return f2fs_dax_huge_fault(vmf, PE_SIZE_PTE);
> +}
> +
> +static int f2fs_dax_pfn_mkwrite(struct vm_fault *vmf)
> +{
> +	struct inode *inode = file_inode(vmf->vma->vm_file);
> +	struct super_block *sb = inode->i_sb;
> +	loff_t size;
> +	int ret;
> +
> +	sb_start_pagefault(sb);
> +	file_update_time(vmf->vma->vm_file);
> +	down_read(&F2FS_I(inode)->i_mmap_sem);
> +	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +	if (vmf->pgoff >= size)
> +		ret = VM_FAULT_SIGBUS;
> +	else
> +		ret = dax_pfn_mkwrite(vmf);
> +	up_read(&F2FS_I(inode)->i_mmap_sem);
> +	sb_end_pagefault(sb);
> +
> +	return ret;
> +}
> +
> +static const struct vm_operations_struct f2fs_dax_vm_ops = {
> +	.fault		= f2fs_dax_fault,
> +	.huge_fault	= f2fs_dax_huge_fault,
> +	.page_mkwrite	= f2fs_dax_fault,
> +	.pfn_mkwrite	= f2fs_dax_pfn_mkwrite,
> +};
> +#else
> +#define f2fs_dax_vm_ops f2fs_file_vm_ops
> +#endif
> +
>  static int get_parent_ino(struct inode *inode, nid_t *pino)
>  {
>  	struct dentry *dentry;
> @@ -436,7 +496,13 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
>  		return err;
>  
>  	file_accessed(file);
> -	vma->vm_ops = &f2fs_file_vm_ops;
> +
> +	if (IS_DAX(inode)) {
> +		vma->vm_ops = &f2fs_dax_vm_ops;
> +		vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
> +	} else
> +		vma->vm_ops = &f2fs_file_vm_ops;
> +
>  	return 0;
>  }
>  
> @@ -520,6 +586,18 @@ static int truncate_partial_data_page(struct inode *inode, u64 from,
>  	if (!offset && !cache_only)
>  		return 0;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode)) {
> +		int ret;
> +
> +		down_read(&F2FS_I(inode)->dio_rwsem[WRITE]);
> +		ret = iomap_zero_range(inode, from, PAGE_SIZE - offset,
> +			NULL, &f2fs_iomap_ops);
> +		up_read(&F2FS_I(inode)->dio_rwsem[WRITE]);
> +		return ret;
> +	}
> +#endif
> +
>  	if (cache_only) {
>  		page = find_lock_page(mapping, index);
>  		if (page && PageUptodate(page))
> @@ -781,6 +859,19 @@ static int fill_zero(struct inode *inode, pgoff_t index,
>  	if (!len)
>  		return 0;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode)) {
> +		int ret;
> +
> +		down_read(&F2FS_I(inode)->dio_rwsem[WRITE]);
> +		ret = iomap_zero_range(inode,
> +			F2FS_BLK_TO_BYTES((loff_t)index) + start,
> +			len, NULL, &f2fs_iomap_ops);
> +		up_read(&F2FS_I(inode)->dio_rwsem[WRITE]);
> +		return ret;
> +	}
> +#endif
> +
>  	f2fs_balance_fs(sbi, true);
>  
>  	f2fs_lock_op(sbi);
> @@ -1103,6 +1194,12 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
>  	loff_t new_size;
>  	int ret;
>  
> +#ifdef CONFIG_FS_DAX
> +	/* The current implementation does not apply to DAX files. */
> +	if (IS_DAX(inode))
> +		return -EINVAL;
> +#endif
> +
>  	if (offset + len >= i_size_read(inode))
>  		return -EINVAL;
>  
> @@ -1293,6 +1390,12 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
>  	loff_t new_size;
>  	int ret = 0;
>  
> +#ifdef CONFIG_FS_DAX
> +	/* The current implementation does not apply to DAX files. */
> +	if (IS_DAX(inode))
> +		return -EINVAL;
> +#endif
> +
>  	new_size = i_size_read(inode) + len;
>  	ret = inode_newsize_ok(inode, new_size);
>  	if (ret)
> @@ -1556,6 +1659,11 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
>  	struct inode *inode = file_inode(filp);
>  	int ret;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode))
> +		return -EINVAL;

Should we allow to enable DAX for inode through F2FS_IOC_SETFLAGS? If it
is allowed, we need to check atomic/volatile tag before dax configuring.

In additional, we should also check dax file for defragment() and
move_range().

> +#endif
> +
>  	if (!inode_owner_or_capable(inode))
>  		return -EACCES;
>  
> @@ -1605,6 +1713,11 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp)
>  	struct inode *inode = file_inode(filp);
>  	int ret;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode))
> +		return -EINVAL;
> +#endif
> +
>  	if (!inode_owner_or_capable(inode))
>  		return -EACCES;
>  
> @@ -1641,6 +1754,11 @@ static int f2fs_ioc_start_volatile_write(struct file *filp)
>  	struct inode *inode = file_inode(filp);
>  	int ret;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode))
> +		return -EINVAL;
> +#endif
> +
>  	if (!inode_owner_or_capable(inode))
>  		return -EACCES;
>  
> @@ -1676,6 +1794,11 @@ static int f2fs_ioc_release_volatile_write(struct file *filp)
>  	struct inode *inode = file_inode(filp);
>  	int ret;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode))
> +		return -EINVAL;
> +#endif
> +
>  	if (!inode_owner_or_capable(inode))
>  		return -EACCES;
>  
> @@ -1705,6 +1828,11 @@ static int f2fs_ioc_abort_volatile_write(struct file *filp)
>  	struct inode *inode = file_inode(filp);
>  	int ret;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode))
> +		return -EINVAL;
> +#endif
> +
>  	if (!inode_owner_or_capable(inode))
>  		return -EACCES;
>  
> @@ -2363,6 +2491,61 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  	}
>  }
>  
> +#ifdef CONFIG_FS_DAX
> +static ssize_t f2fs_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> +	struct inode *inode = file_inode(iocb->ki_filp);
> +	ssize_t ret;
> +
> +	inode_lock_shared(inode);
> +
> +	if (!IS_DAX(inode)) {
> +		inode_unlock_shared(inode);
> +		return generic_file_read_iter(iocb, to);
> +	}
> +
> +	down_read(&F2FS_I(inode)->dio_rwsem[READ]);
> +	ret = dax_iomap_rw(iocb, to, &f2fs_iomap_ops);
> +	up_read(&F2FS_I(inode)->dio_rwsem[READ]);
> +	inode_unlock_shared(inode);
> +
> +	file_accessed(iocb->ki_filp);
> +	return ret;
> +}
> +
> +static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> +	if (!iov_iter_count(to))
> +		return 0; /* skip atime */
> +
> +	if (IS_DAX(file_inode(iocb->ki_filp)))
> +		return f2fs_dax_read_iter(iocb, to);
> +
> +	return generic_file_read_iter(iocb, to);
> +}
> +
> +static ssize_t f2fs_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
> +{
> +	struct inode *inode = file_inode(iocb->ki_filp);
> +	ssize_t ret;
> +
> +	ret = file_remove_privs(iocb->ki_filp);
> +	if (ret)
> +		return ret;
> +	ret = file_update_time(iocb->ki_filp);
> +	if (ret)
> +		return ret;
> +
> +	down_read(&F2FS_I(inode)->dio_rwsem[WRITE]);
> +	ret = dax_iomap_rw(iocb, from, &f2fs_iomap_ops);
> +	up_read(&F2FS_I(inode)->dio_rwsem[WRITE]);
> +
> +	return ret;
> +}
> +#else
> +#define f2fs_dax_write_iter	__generic_file_write_iter
> +#endif
> +
>  static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>  {
>  	struct file *file = iocb->ki_filp;
> @@ -2384,7 +2567,10 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>  			return err;
>  		}
>  		blk_start_plug(&plug);
> -		ret = __generic_file_write_iter(iocb, from);
> +		if (IS_DAX(inode))
> +			ret = f2fs_dax_write_iter(iocb, from);
> +		else
> +			ret = __generic_file_write_iter(iocb, from);
>  		blk_finish_plug(&plug);
>  		clear_inode_flag(inode, FI_NO_PREALLOC);
>  	}
> @@ -2432,7 +2618,11 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  
>  const struct file_operations f2fs_file_operations = {
>  	.llseek		= f2fs_llseek,
> +#ifdef CONFIG_FS_DAX
> +	.read_iter	= f2fs_file_read_iter,
> +#else
>  	.read_iter	= generic_file_read_iter,
> +#endif
>  	.write_iter	= f2fs_file_write_iter,
>  	.open		= f2fs_file_open,
>  	.release	= f2fs_release_file,
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index fa3d2e2..3d24afe 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -16,6 +16,7 @@
>  #include <linux/kthread.h>
>  #include <linux/delay.h>
>  #include <linux/freezer.h>
> +#include <linux/dax.h>
>  
>  #include "f2fs.h"
>  #include "node.h"
> @@ -700,6 +701,88 @@ static void move_encrypted_block(struct inode *inode, block_t bidx,
>  	f2fs_put_page(page, 1);
>  }
>  
> +static void dax_move_data_page(struct inode *inode, block_t bidx,
> +				unsigned int segno, int off)
> +{
> +	struct block_device *bdev = inode->i_sb->s_bdev;
> +	struct dax_device *dax_dev;
> +	struct dnode_of_data dn;
> +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> +	struct f2fs_summary sum;
> +	struct node_info ni;
> +	block_t old_blkaddr, new_blkaddr;
> +	int err, id;
> +	long map_len;
> +	pgoff_t pgoff;
> +	void *kaddr_old, *kaddr_new;
> +	pfn_t pfn;
> +
> +	if (blk_queue_dax(bdev->bd_queue))
> +		dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
> +	else
> +		return;
> +
> +	if (!check_valid_map(sbi, segno, off))
> +		return;
> +
> +	if (f2fs_is_atomic_file(inode))
> +		return;

It must not be an atomic opened file, could we change to add bug_on in
the beginning of this function until we support dax for atomic file?

> +
> +	if (!down_write_trylock(&F2FS_I(inode)->i_mmap_sem))
> +		return;
> +
> +	unmap_mapping_range(inode->i_mapping, (loff_t)bidx << PAGE_SHIFT,
> +			PAGE_SIZE, 1);
> +	/* find the old block address */
> +	set_new_dnode(&dn, inode, NULL, NULL, 0);
> +	err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
> +	if (err)
> +		goto out_map;
> +	old_blkaddr = dn.data_blkaddr;
> +	/* This page is already truncated */
> +	if (old_blkaddr == NULL_ADDR) {
> +		f2fs_put_dnode(&dn);
> +		goto out_map;
> +	}
> +
> +	/* allocate a new block address */
> +	get_node_info(sbi, dn.nid, &ni);
> +	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
> +	allocate_data_block(sbi, NULL, old_blkaddr, &new_blkaddr,
> +			&sum, CURSEG_COLD_DATA, NULL, false);
> +
> +	/* copy data page from old to new address in dax_bdev */
> +	id = dax_read_lock();
> +	err = bdev_dax_pgoff(bdev, SECTOR_FROM_BLOCK(old_blkaddr),
> +			PAGE_SIZE, &pgoff);
> +	if (err)

Once you allocated new block address, meanwhile sit/ssa info will be
changed as well, so, in error path, we should do the recovery with
__f2fs_replace_block.

> +		goto unlock;
> +	map_len = dax_direct_access(dax_dev, pgoff, 1, &kaddr_old, &pfn);
> +	if (map_len < 0)
> +		goto unlock;
> +	err = bdev_dax_pgoff(bdev, SECTOR_FROM_BLOCK(new_blkaddr),
> +			PAGE_SIZE, &pgoff);
> +	if (err)
> +		goto unlock;
> +	map_len = dax_direct_access(dax_dev, pgoff, 1, &kaddr_new, &pfn);
> +	if (map_len < 0)
> +		goto unlock;
> +	copy_page((void __force *)kaddr_new, (void __force *)kaddr_old);
> +
> +	f2fs_update_data_blkaddr(&dn, new_blkaddr);
> +	set_inode_flag(inode, FI_APPEND_WRITE);
> +	if (bidx == 0)
> +		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
> +	f2fs_put_dnode(&dn);

we should include f2fs_put_dnode in error path.

> +
> +unlock:
> +	dax_read_unlock(id);
> +out_map:
> +	unmap_mapping_range(inode->i_mapping, (loff_t)bidx << PAGE_SHIFT,
> +			PAGE_SIZE, 1);
> +	up_write(&F2FS_I(inode)->i_mmap_sem);

We need release dax_dev here.

> +}
> +
>  static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
>  							unsigned int segno, int off)
>  {
> @@ -818,9 +901,9 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  			if (IS_ERR(inode) || is_bad_inode(inode))
>  				continue;
>  
> -			/* if encrypted inode, let's go phase 3 */
> -			if (f2fs_encrypted_inode(inode) &&
> -						S_ISREG(inode->i_mode)) {
> +			/* if DAX or encrypted inode, let's go phase 3 */
> +			if (IS_DAX(inode) || (f2fs_encrypted_inode(inode) &&
> +						S_ISREG(inode->i_mode))) {
>  				add_gc_inode(gc_list, inode);
>  				continue;
>  			}
> @@ -858,7 +941,9 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>  
>  			start_bidx = start_bidx_of_node(nofs, inode)
>  								+ ofs_in_node;
> -			if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
> +			if (IS_DAX(inode))
> +				dax_move_data_page(inode, start_bidx, segno, off);
> +			else if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
>  				move_encrypted_block(inode, start_bidx, segno, off);
>  			else
>  				move_data_page(inode, start_bidx, gc_type, segno, off);
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index e4c527c..f858817 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -28,6 +28,10 @@ bool f2fs_may_inline_data(struct inode *inode)
>  	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
>  		return false;
>  
> +#ifdef CONFIG_FS_DAX
> +	if (IS_DAX(inode))
> +		return false;
> +#endif
>  	return true;
>  }
>  
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index c31b40e..f3edc6c 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -60,6 +60,12 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode)
>  	if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode))
>  		f2fs_set_encrypted_inode(inode);
>  
> +#ifdef CONFIG_FS_DAX
> +	if (test_opt(sbi, DAX) && S_ISREG(inode->i_mode) &&
> +	!f2fs_has_inline_data(inode) && !f2fs_encrypted_inode(inode))

Coding style.

if (test_opt(sbi, DAX) && S_ISREG(inode->i_mode) &&
	!f2fs_has_inline_data(inode) && !f2fs_encrypted_inode(inode))

> +		inode->i_flags |= S_DAX;
> +#endif
> +
>  	set_inode_flag(inode, FI_NEW_INODE);
>  
>  	if (test_opt(sbi, INLINE_XATTR))
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index ddd2973..02cda00 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -108,6 +108,7 @@ enum {
>  	Opt_fault_injection,
>  	Opt_lazytime,
>  	Opt_nolazytime,
> +	Opt_dax,
>  	Opt_err,
>  };
>  
> @@ -143,6 +144,7 @@ enum {
>  	{Opt_fault_injection, "fault_injection=%u"},
>  	{Opt_lazytime, "lazytime"},
>  	{Opt_nolazytime, "nolazytime"},
> +	{Opt_dax, "dax"},
>  	{Opt_err, NULL},
>  };
>  
> @@ -490,6 +492,15 @@ static int parse_options(struct super_block *sb, char *options)
>  			f2fs_msg(sb, KERN_INFO, "noacl options not supported");
>  			break;
>  #endif
> +#ifdef CONFIG_FS_DAX
> +		case Opt_dax:
> +			set_opt(sbi, DAX);
> +			break;
> +#else
> +		case Opt_dax:
> +			f2fs_msg(sb, KERN_INFO, "dax options not supported");

s/options/option

Thanks,

> +			break;
> +#endif
>  		case Opt_active_logs:
>  			if (args->from && match_int(args, &arg))
>  				return -EINVAL;
> @@ -986,6 +997,10 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>  	if (test_opt(sbi, FAULT_INJECTION))
>  		seq_puts(seq, ",fault_injection");
>  #endif
> +#ifdef CONFIG_FS_DAX
> +	if (test_opt(sbi, DAX))
> +		seq_puts(seq, ",dax");
> +#endif
>  
>  	return 0;
>  }
>