[PATCH 2/6] NFSD: filecache: add STATX_DIOALIGN and STATX_DIO_READ_ALIGN support

[Mike Snitzer <snitzer@kernel.org>]

Use STATX_DIOALIGN and STATX_DIO_READ_ALIGN to get and store DIO
alignment attributes from underlying filesystem in associated
nfsd_file.  This is done when the nfsd_file is first opened for
a regular file.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 fs/nfsd/filecache.c | 32 ++++++++++++++++++++++++++++++++
 fs/nfsd/filecache.h |  4 ++++
 fs/nfsd/vfs.c       | 17 +++++++++++++++++
 fs/nfsd/vfs.h       | 15 ++-------------
 4 files changed, 55 insertions(+), 13 deletions(-)

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 0acad9c35b3f..01598e7b0071 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;
 }
 
@@ -1069,6 +1072,33 @@ nfsd_file_is_cached(struct inode *inode)
 	return ret;
 }
 
+static __be32
+nfsd_file_getattr(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;
+
+	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 status;
+}
+
 static __be32
 nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net,
 		     struct svc_cred *cred,
@@ -1187,6 +1217,8 @@ 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_getattr(fhp, nf);
 		}
 	} else
 		status = nfserr_jukebox;
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 722b26c71e45..237a05c74211 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/vfs.c b/fs/nfsd/vfs.c
index bba3e6f4f56b..8dccbb4d78f9 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -2672,3 +2672,20 @@ nfsd_permission(struct svc_cred *cred, struct svc_export *exp,
 
 	return err? nfserrno(err) : 0;
 }
+
+__be32 fh_getattr(const struct svc_fh *fh, struct kstat *stat)
+{
+	u32 request_mask = STATX_BASIC_STATS;
+	struct path p = {.mnt = fh->fh_export->ex_path.mnt,
+			 .dentry = fh->fh_dentry};
+	struct inode *inode = d_inode(p.dentry);
+
+	if (nfsd_enable_dontcache && S_ISREG(inode->i_mode))
+		request_mask |= (STATX_DIOALIGN | STATX_DIO_READ_ALIGN);
+
+	if (fh->fh_maxsize == NFS4_FHSIZE)
+		request_mask |= (STATX_BTIME | STATX_CHANGE_COOKIE);
+
+	return nfserrno(vfs_getattr(&p, stat, request_mask,
+				    AT_STATX_SYNC_AS_STAT));
+}
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index eff04959606f..e3de3a295704 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -160,6 +160,8 @@ __be32		nfsd_permission(struct svc_cred *cred, struct svc_export *exp,
 
 void		nfsd_filp_close(struct file *fp);
 
+__be32          fh_getattr(const struct svc_fh *fh, struct kstat *stat);
+
 static inline int fh_want_write(struct svc_fh *fh)
 {
 	int ret;
@@ -180,17 +182,4 @@ static inline void fh_drop_write(struct svc_fh *fh)
 	}
 }
 
-static inline __be32 fh_getattr(const struct svc_fh *fh, struct kstat *stat)
-{
-	u32 request_mask = STATX_BASIC_STATS;
-	struct path p = {.mnt = fh->fh_export->ex_path.mnt,
-			 .dentry = fh->fh_dentry};
-
-	if (fh->fh_maxsize == NFS4_FHSIZE)
-		request_mask |= (STATX_BTIME | STATX_CHANGE_COOKIE);
-
-	return nfserrno(vfs_getattr(&p, stat, request_mask,
-				    AT_STATX_SYNC_AS_STAT));
-}
-
 #endif /* LINUX_NFSD_VFS_H */
-- 
2.44.0