Re: [PATCH v3 1/3] NFSD: filecache: add STATX_DIOALIGN and STATX_DIO_READ_ALIGN support

[Chuck Lever <cel@kernel.org>]

On 9/22/25 7:11 AM, Chuck Lever wrote:
> From: Mike Snitzer <snitzer@kernel.org>
> 
> Use STATX_DIOALIGN and STATX_DIO_READ_ALIGN to get DIO alignment
> attributes from the underlying filesystem and store them in the
> associated nfsd_file. This is done when the nfsd_file is first
> opened for each regular file.
> 
> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> Reviewed-by: NeilBrown <neil@brown.name>
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

v3 of this patch is the one that should be included for the client
series you plan to merge.

When you apply it, please remove "Signed-off-by: Chuck ..." and
replace it with:

Acked-by: Chuck Lever <chuck.lever@oracle.com>


> ---
>  fs/nfsd/filecache.c     | 34 ++++++++++++++++++++++++++++++++++
>  fs/nfsd/filecache.h     |  4 ++++
>  fs/nfsd/nfsfh.c         |  4 ++++
>  fs/nfsd/trace.h         | 27 +++++++++++++++++++++++++++
>  include/trace/misc/fs.h | 22 ++++++++++++++++++++++
>  5 files changed, 91 insertions(+)
> 
> diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
> index 75bc48031c07..78cca0d751ac 100644
> --- a/fs/nfsd/filecache.c
> +++ b/fs/nfsd/filecache.c
> @@ -231,6 +231,9 @@ nfsd_file_alloc(struct net *net, struct inode *inode, unsigned char need,
>  	refcount_set(&nf->nf_ref, 1);
>  	nf->nf_may = need;
>  	nf->nf_mark = NULL;
> +	nf->nf_dio_mem_align = 0;
> +	nf->nf_dio_offset_align = 0;
> +	nf->nf_dio_read_offset_align = 0;
>  	return nf;
>  }
>  
> @@ -1048,6 +1051,35 @@ nfsd_file_is_cached(struct inode *inode)
>  	return ret;
>  }
>  
> +static __be32
> +nfsd_file_get_dio_attrs(const struct svc_fh *fhp, struct nfsd_file *nf)
> +{
> +	struct inode *inode = file_inode(nf->nf_file);
> +	struct kstat stat;
> +	__be32 status;
> +
> +	/* Currently only need to get DIO alignment info for regular files */
> +	if (!S_ISREG(inode->i_mode))
> +		return nfs_ok;
> +
> +	status = fh_getattr(fhp, &stat);
> +	if (status != nfs_ok)
> +		return status;
> +
> +	trace_nfsd_file_get_dio_attrs(inode, &stat);
> +
> +	if (stat.result_mask & STATX_DIOALIGN) {
> +		nf->nf_dio_mem_align = stat.dio_mem_align;
> +		nf->nf_dio_offset_align = stat.dio_offset_align;
> +	}
> +	if (stat.result_mask & STATX_DIO_READ_ALIGN)
> +		nf->nf_dio_read_offset_align = stat.dio_read_offset_align;
> +	else
> +		nf->nf_dio_read_offset_align = nf->nf_dio_offset_align;
> +
> +	return nfs_ok;
> +}
> +
>  static __be32
>  nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net,
>  		     struct svc_cred *cred,
> @@ -1166,6 +1198,8 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net,
>  			}
>  			status = nfserrno(ret);
>  			trace_nfsd_file_open(nf, status);
> +			if (status == nfs_ok)
> +				status = nfsd_file_get_dio_attrs(fhp, nf);
>  		}
>  	} else
>  		status = nfserr_jukebox;
> diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
> index 24ddf60e8434..e3d6ca2b6030 100644
> --- a/fs/nfsd/filecache.h
> +++ b/fs/nfsd/filecache.h
> @@ -54,6 +54,10 @@ struct nfsd_file {
>  	struct list_head	nf_gc;
>  	struct rcu_head		nf_rcu;
>  	ktime_t			nf_birthtime;
> +
> +	u32			nf_dio_mem_align;
> +	u32			nf_dio_offset_align;
> +	u32			nf_dio_read_offset_align;
>  };
>  
>  int nfsd_file_cache_init(void);
> diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
> index 3edccc38db42..3eb724ec9566 100644
> --- a/fs/nfsd/nfsfh.c
> +++ b/fs/nfsd/nfsfh.c
> @@ -696,8 +696,12 @@ __be32 fh_getattr(const struct svc_fh *fhp, struct kstat *stat)
>  		.mnt		= fhp->fh_export->ex_path.mnt,
>  		.dentry		= fhp->fh_dentry,
>  	};
> +	struct inode *inode = d_inode(p.dentry);
>  	u32 request_mask = STATX_BASIC_STATS;
>  
> +	if (S_ISREG(inode->i_mode))
> +		request_mask |= (STATX_DIOALIGN | STATX_DIO_READ_ALIGN);
> +
>  	if (fhp->fh_maxsize == NFS4_FHSIZE)
>  		request_mask |= (STATX_BTIME | STATX_CHANGE_COOKIE);
>  
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index a664fdf1161e..6e2c8e2aab10 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -1133,6 +1133,33 @@ TRACE_EVENT(nfsd_file_alloc,
>  	)
>  );
>  
> +TRACE_EVENT(nfsd_file_get_dio_attrs,
> +	TP_PROTO(
> +		const struct inode *inode,
> +		const struct kstat *stat
> +	),
> +	TP_ARGS(inode, stat),
> +	TP_STRUCT__entry(
> +		__field(const void *, inode)
> +		__field(unsigned long, mask)
> +		__field(u32, mem_align)
> +		__field(u32, offset_align)
> +		__field(u32, read_offset_align)
> +	),
> +	TP_fast_assign(
> +		__entry->inode = inode;
> +		__entry->mask = stat->result_mask;
> +		__entry->mem_align = stat->dio_mem_align;
> +		__entry->offset_align = stat->dio_offset_align;
> +		__entry->read_offset_align = stat->dio_read_offset_align;
> +	),
> +	TP_printk("inode=%p flags=%s mem_align=%u offset_align=%u read_offset_align=%u",
> +		__entry->inode, show_statx_mask(__entry->mask),
> +		__entry->mem_align, __entry->offset_align,
> +		__entry->read_offset_align
> +	)
> +);
> +
>  TRACE_EVENT(nfsd_file_acquire,
>  	TP_PROTO(
>  		const struct svc_rqst *rqstp,
> diff --git a/include/trace/misc/fs.h b/include/trace/misc/fs.h
> index 0406ebe2a80a..7ead1c61f0cb 100644
> --- a/include/trace/misc/fs.h
> +++ b/include/trace/misc/fs.h
> @@ -141,3 +141,25 @@
>  		{ ATTR_TIMES_SET,	"TIMES_SET" },	\
>  		{ ATTR_TOUCH,		"TOUCH"},	\
>  		{ ATTR_DELEG,		"DELEG"})
> +
> +#define show_statx_mask(flags)					\
> +	__print_flags(flags, "|",				\
> +		{ STATX_TYPE,		"TYPE" },		\
> +		{ STATX_MODE,		"MODE" },		\
> +		{ STATX_NLINK,		"NLINK" },		\
> +		{ STATX_UID,		"UID" },		\
> +		{ STATX_GID,		"GID" },		\
> +		{ STATX_ATIME,		"ATIME" },		\
> +		{ STATX_MTIME,		"MTIME" },		\
> +		{ STATX_CTIME,		"CTIME" },		\
> +		{ STATX_INO,		"INO" },		\
> +		{ STATX_SIZE,		"SIZE" },		\
> +		{ STATX_BLOCKS,		"BLOCKS" },		\
> +		{ STATX_BASIC_STATS,	"BASIC_STATS" },	\
> +		{ STATX_BTIME,		"BTIME" },		\
> +		{ STATX_MNT_ID,		"MNT_ID" },		\
> +		{ STATX_DIOALIGN,	"DIOALIGN" },		\
> +		{ STATX_MNT_ID_UNIQUE,	"MNT_ID_UNIQUE" },	\
> +		{ STATX_SUBVOL,		"SUBVOL" },		\
> +		{ STATX_WRITE_ATOMIC,	"WRITE_ATOMIC" },	\
> +		{ STATX_DIO_READ_ALIGN,	"DIO_READ_ALIGN" })

-- 
Chuck Lever