Re: [PATCH 3/3] xfs: persist S_IOMAP_IMMUTABLE in di_flags2

[Darrick J. Wong]

On Sat, Jul 29, 2017 at 12:43:46PM -0700, Dan Williams wrote:
> Record the immutable state in the on-disk inode so that on the next boot
> the protections against reflink and hole punch etc are automatically
> restored.
> 
> This deliberately does not add a FS_XFLAG_IOMAP_IMMUTABLE since
> fallocate(2) is the path to toggle this flag.
> 
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
> Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx>
> Suggested-by: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
>  fs/xfs/libxfs/xfs_format.h |    5 ++++-
>  fs/xfs/xfs_bmap_util.c     |   14 +++++++++++---
>  fs/xfs/xfs_bmap_util.h     |    2 +-
>  fs/xfs/xfs_file.c          |    4 ++--
>  fs/xfs/xfs_ioctl.c         |    4 ++--
>  fs/xfs/xfs_iops.c          |    8 +++++---
>  6 files changed, 25 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index d4d9bef20c3a..9e720e55776b 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -1063,12 +1063,15 @@ static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
>  #define XFS_DIFLAG2_DAX_BIT	0	/* use DAX for this inode */
>  #define XFS_DIFLAG2_REFLINK_BIT	1	/* file's blocks may be shared */
>  #define XFS_DIFLAG2_COWEXTSIZE_BIT   2  /* copy on write extent size hint */
> +#define XFS_DIFLAG2_IOMAP_IMMUTABLE_BIT 3 /* set S_IOMAP_IMMUTABLE for this inode */
>  #define XFS_DIFLAG2_DAX		(1 << XFS_DIFLAG2_DAX_BIT)
>  #define XFS_DIFLAG2_REFLINK     (1 << XFS_DIFLAG2_REFLINK_BIT)
>  #define XFS_DIFLAG2_COWEXTSIZE  (1 << XFS_DIFLAG2_COWEXTSIZE_BIT)
> +#define XFS_DIFLAG2_IOMAP_IMMUTABLE (1 << XFS_DIFLAG2_IOMAP_IMMUTABLE_BIT)
>  
>  #define XFS_DIFLAG2_ANY \
> -	(XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE)
> +	(XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE | \
> +	 XFS_DIFLAG2_IOMAP_IMMUTABLE)
>  
>  /*
>   * Inode number format:
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index c4fc79a0704f..1dcb521da456 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1021,7 +1021,8 @@ xfs_alloc_file_space(
>  	struct xfs_inode	*ip,
>  	xfs_off_t		offset,
>  	xfs_off_t		len,
> -	int			alloc_type)
> +	int			alloc_type,
> +	uint64_t		di_flags2)
>  {
>  	xfs_mount_t		*mp = ip->i_mount;
>  	xfs_off_t		count;
> @@ -1119,6 +1120,12 @@ xfs_alloc_file_space(
>  			break;
>  		}
>  		xfs_ilock(ip, XFS_ILOCK_EXCL);
> +		if (di_flags2) {
> +			/* fold inode attributes for this allocation */
> +			ip->i_d.di_flags2 |= di_flags2;
> +			di_flags2 = 0;

Can we set the inode flag in xfs_seal_file_space instead of plumbing
di_flags2 all over the place into the bmap routines?

Also, what does

  xfs_alloc_file_space(..., XFS_BMAPI_ATTRFORK, XFS_DIFLAG2_REFLINK);

mean? :)

--D

> +		}
> +
>  		error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks,
>  						      0, quota_flag);
>  		if (error)
> @@ -1381,7 +1388,7 @@ xfs_zero_file_space(
>  	error = xfs_alloc_file_space(ip, round_down(offset, blksize),
>  				     round_up(offset + len, blksize) -
>  				     round_down(offset, blksize),
> -				     XFS_BMAPI_PREALLOC);
> +				     XFS_BMAPI_PREALLOC, 0);
>  out:
>  	return error;
>  
> @@ -1461,7 +1468,8 @@ xfs_seal_file_space(
>  		goto err;
>  
>  	error = xfs_alloc_file_space(ip, offset, len,
> -			XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO);
> +			XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO,
> +			XFS_DIFLAG2_IOMAP_IMMUTABLE);
>  	if (error)
>  		goto err;
>  
> diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h
> index 5115a32a2483..1698e0c58b78 100644
> --- a/fs/xfs/xfs_bmap_util.h
> +++ b/fs/xfs/xfs_bmap_util.h
> @@ -51,7 +51,7 @@ int	xfs_bmap_last_extent(struct xfs_trans *tp, struct xfs_inode *ip,
>  
>  /* preallocation and hole punch interface */
>  int	xfs_alloc_file_space(struct xfs_inode *ip, xfs_off_t offset,
> -			     xfs_off_t len, int alloc_type);
> +			     xfs_off_t len, int alloc_type, uint64_t di_flags2);
>  int	xfs_free_file_space(struct xfs_inode *ip, xfs_off_t offset,
>  			    xfs_off_t len);
>  int	xfs_zero_file_space(struct xfs_inode *ip, xfs_off_t offset,
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index e21121530a90..2d9ffa1773bd 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -837,12 +837,12 @@ xfs_file_fallocate(
>  					goto out_unlock;
>  
>  				error = xfs_alloc_file_space(ip, offset, len,
> -						XFS_BMAPI_PREALLOC);
> +						XFS_BMAPI_PREALLOC, 0);
>  			} else if (mode & FALLOC_FL_SEAL_BLOCK_MAP) {
>  				error = xfs_seal_file_space(ip, offset, len);
>  			} else
>  				error = xfs_alloc_file_space(ip, offset, len,
> -						XFS_BMAPI_PREALLOC);
> +						XFS_BMAPI_PREALLOC, 0);
>  		}
>  		if (error)
>  			goto out_unlock;
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 2e64488bc4de..c829f85bed99 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -703,7 +703,7 @@ xfs_ioc_space(
>  	case XFS_IOC_RESVSP64:
>  		flags |= XFS_PREALLOC_SET;
>  		error = xfs_alloc_file_space(ip, bf->l_start, bf->l_len,
> -						XFS_BMAPI_PREALLOC);
> +						XFS_BMAPI_PREALLOC, 0);
>  		break;
>  	case XFS_IOC_UNRESVSP:
>  	case XFS_IOC_UNRESVSP64:
> @@ -716,7 +716,7 @@ xfs_ioc_space(
>  		flags |= XFS_PREALLOC_CLEAR;
>  		if (bf->l_start > XFS_ISIZE(ip)) {
>  			error = xfs_alloc_file_space(ip, XFS_ISIZE(ip),
> -					bf->l_start - XFS_ISIZE(ip), 0);
> +					bf->l_start - XFS_ISIZE(ip), 0, 0);
>  			if (error)
>  				goto out_unlock;
>  		}
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 469c9fa4c178..174ef95453f5 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -1186,9 +1186,10 @@ xfs_diflags_to_iflags(
>  	struct xfs_inode	*ip)
>  {
>  	uint16_t		flags = ip->i_d.di_flags;
> +	uint64_t		flags2 = ip->i_d.di_flags2;
>  
>  	inode->i_flags &= ~(S_IMMUTABLE | S_APPEND | S_SYNC |
> -			    S_NOATIME | S_DAX);
> +			    S_NOATIME | S_DAX | S_IOMAP_IMMUTABLE);
>  
>  	if (flags & XFS_DIFLAG_IMMUTABLE)
>  		inode->i_flags |= S_IMMUTABLE;
> @@ -1201,9 +1202,10 @@ xfs_diflags_to_iflags(
>  	if (S_ISREG(inode->i_mode) &&
>  	    ip->i_mount->m_sb.sb_blocksize == PAGE_SIZE &&
>  	    !xfs_is_reflink_inode(ip) &&
> -	    (ip->i_mount->m_flags & XFS_MOUNT_DAX ||
> -	     ip->i_d.di_flags2 & XFS_DIFLAG2_DAX))
> +	    (ip->i_mount->m_flags & XFS_MOUNT_DAX || flags2 & XFS_DIFLAG2_DAX))
>  		inode->i_flags |= S_DAX;
> +	if (flags2 & XFS_DIFLAG2_IOMAP_IMMUTABLE)
> +		inode->i_flags |= S_IOMAP_IMMUTABLE;
>  }
>  
>  /*
> 
> --
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