nfsd: add support for delegated timestamps

Add support for the delegated timestamps on write delegations. This
allows the server to proxy timestamps from the delegation holder to
other clients that are doing GETATTRs vs. the same inode.

When OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS bit is set in the OPEN
call, set the dl_type to the *_ATTRS_DELEG flavor of delegation.

Add timespec64 fields to nfs4_cb_fattr and decode the timestamps into
those. Vet those timestamps according to the delstid spec and update
the inode attrs if necessary.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

7 files changed, 152 insertions, 23 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 1457f61ae051..50e468bdb8d4 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -42,6 +42,7 @@
 #include "trace.h"
 #include "xdr4cb.h"
 #include "xdr4.h"
+#include "nfs4xdr_gen.h"
 
 #define NFSDDBG_FACILITY                NFSDDBG_PROC
 
@@ -93,12 +94,35 @@ static int decode_cb_fattr4(struct xdr_stream *xdr, uint32_t *bitmap,
 {
 	fattr->ncf_cb_change = 0;
 	fattr->ncf_cb_fsize = 0;
+	fattr->ncf_cb_atime.tv_sec = 0;
+	fattr->ncf_cb_atime.tv_nsec = 0;
+	fattr->ncf_cb_mtime.tv_sec = 0;
+	fattr->ncf_cb_mtime.tv_nsec = 0;
+
 	if (bitmap[0] & FATTR4_WORD0_CHANGE)
 		if (xdr_stream_decode_u64(xdr, &fattr->ncf_cb_change) < 0)
 			return -NFSERR_BAD_XDR;
 	if (bitmap[0] & FATTR4_WORD0_SIZE)
 		if (xdr_stream_decode_u64(xdr, &fattr->ncf_cb_fsize) < 0)
 			return -NFSERR_BAD_XDR;
+	if (bitmap[2] & FATTR4_WORD2_TIME_DELEG_ACCESS) {
+		fattr4_time_deleg_access access;
+
+		if (!xdrgen_decode_fattr4_time_deleg_access(xdr, &access))
+			return -NFSERR_BAD_XDR;
+		fattr->ncf_cb_atime.tv_sec = access.seconds;
+		fattr->ncf_cb_atime.tv_nsec = access.nseconds;
+
+	}
+	if (bitmap[2] & FATTR4_WORD2_TIME_DELEG_MODIFY) {
+		fattr4_time_deleg_modify modify;
+
+		if (!xdrgen_decode_fattr4_time_deleg_modify(xdr, &modify))
+			return -NFSERR_BAD_XDR;
+		fattr->ncf_cb_mtime.tv_sec = modify.seconds;
+		fattr->ncf_cb_mtime.tv_nsec = modify.nseconds;
+
+	}
 	return 0;
 }
 
@@ -364,15 +388,21 @@ encode_cb_getattr4args(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr,
 	struct nfs4_delegation *dp = container_of(fattr, struct nfs4_delegation, dl_cb_fattr);
 	struct knfsd_fh *fh = &dp->dl_stid.sc_file->fi_fhandle;
 	struct nfs4_cb_fattr *ncf = &dp->dl_cb_fattr;
-	u32 bmap[1];
+	u32 bmap_size = 1;
+	u32 bmap[3];
 
 	bmap[0] = FATTR4_WORD0_SIZE;
 	if (!ncf->ncf_file_modified)
 		bmap[0] |= FATTR4_WORD0_CHANGE;
 
+	if (deleg_attrs_deleg(dp->dl_type)) {
+		bmap[1] = 0;
+		bmap[2] = FATTR4_WORD2_TIME_DELEG_ACCESS | FATTR4_WORD2_TIME_DELEG_MODIFY;
+		bmap_size = 3;
+	}
 	encode_nfs_cb_opnum4(xdr, OP_CB_GETATTR);
 	encode_nfs_fh4(xdr, fh);
-	encode_bitmap4(xdr, bmap, ARRAY_SIZE(bmap));
+	encode_bitmap4(xdr, bmap, bmap_size);
 	hdr->nops++;
 }
 
@@ -636,7 +666,7 @@ static int nfs4_xdr_dec_cb_getattr(struct rpc_rqst *rqstp,
 	struct nfs4_cb_compound_hdr hdr;
 	int status;
 	u32 bitmap[3] = {0};
-	u32 attrlen;
+	u32 attrlen, maxlen;
 	struct nfs4_cb_fattr *ncf =
 		container_of(cb, struct nfs4_cb_fattr, ncf_getattr);
 
@@ -655,7 +685,11 @@ static int nfs4_xdr_dec_cb_getattr(struct rpc_rqst *rqstp,
 		return -NFSERR_BAD_XDR;
 	if (xdr_stream_decode_u32(xdr, &attrlen) < 0)
 		return -NFSERR_BAD_XDR;
-	if (attrlen > (sizeof(ncf->ncf_cb_change) + sizeof(ncf->ncf_cb_fsize)))
+	maxlen = sizeof(ncf->ncf_cb_change) + sizeof(ncf->ncf_cb_fsize);
+	if (bitmap[2] != 0)
+		maxlen += (sizeof(ncf->ncf_cb_mtime.tv_sec) +
+			   sizeof(ncf->ncf_cb_mtime.tv_nsec)) * 2;
+	if (attrlen > maxlen)
 		return -NFSERR_BAD_XDR;
 	status = decode_cb_fattr4(xdr, bitmap, ncf);
 	return status;
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 780db0992c9f..5e1d30b91738 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5951,13 +5951,14 @@ static struct nfs4_delegation *
 nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 		    struct svc_fh *parent)
 {
-	int status = 0;
+	bool deleg_ts = open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS;
 	struct nfs4_client *clp = stp->st_stid.sc_client;
 	struct nfs4_file *fp = stp->st_stid.sc_file;
 	struct nfs4_clnt_odstate *odstate = stp->st_clnt_odstate;
 	struct nfs4_delegation *dp;
 	struct nfsd_file *nf = NULL;
 	struct file_lease *fl;
+	int status = 0;
 	u32 dl_type;
 
 	/*
@@ -5982,7 +5983,7 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	 */
 	if ((open->op_share_access & NFS4_SHARE_ACCESS_BOTH) == NFS4_SHARE_ACCESS_BOTH) {
 		nf = find_rw_file(fp);
-		dl_type = OPEN_DELEGATE_WRITE;
+		dl_type = deleg_ts ? OPEN_DELEGATE_WRITE_ATTRS_DELEG : OPEN_DELEGATE_WRITE;
 	}
 
 	/*
@@ -5991,7 +5992,7 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	 */
 	if (!nf && (open->op_share_access & NFS4_SHARE_ACCESS_READ)) {
 		nf = find_readable_file(fp);
-		dl_type = OPEN_DELEGATE_READ;
+		dl_type = deleg_ts ? OPEN_DELEGATE_READ_ATTRS_DELEG : OPEN_DELEGATE_READ;
 	}
 
 	if (!nf)
@@ -6149,13 +6150,14 @@ static void
 nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 		     struct svc_fh *currentfh)
 {
-	struct nfs4_delegation *dp;
+	bool deleg_ts = open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS;
 	struct nfs4_openowner *oo = openowner(stp->st_stateowner);
 	struct nfs4_client *clp = stp->st_stid.sc_client;
 	struct svc_fh *parent = NULL;
-	int cb_up;
-	int status = 0;
+	struct nfs4_delegation *dp;
 	struct kstat stat;
+	int status = 0;
+	int cb_up;
 
 	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
 	open->op_recall = false;
@@ -6196,12 +6198,14 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 			destroy_delegation(dp);
 			goto out_no_deleg;
 		}
-		open->op_delegate_type = OPEN_DELEGATE_WRITE;
+		open->op_delegate_type = deleg_ts ? OPEN_DELEGATE_WRITE_ATTRS_DELEG :
+						    OPEN_DELEGATE_WRITE;
 		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
 		dp->dl_cb_fattr.ncf_initial_cinfo = nfsd4_change_attribute(&stat);
 		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
 	} else {
-		open->op_delegate_type = OPEN_DELEGATE_READ;
+		open->op_delegate_type = deleg_ts ? OPEN_DELEGATE_READ_ATTRS_DELEG :
+						    OPEN_DELEGATE_READ;
 		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
 	}
 	nfs4_put_stid(&dp->dl_stid);
@@ -9018,6 +9022,78 @@ nfsd4_get_writestateid(struct nfsd4_compound_state *cstate,
 }
 
 /**
+ * set_cb_time - vet and set the timespec for a cb_getattr update
+ * @cb: timestamp from the CB_GETATTR response
+ * @orig: original timestamp in the inode
+ * @now: current time
+ *
+ * Given a timestamp in a CB_GETATTR response, check it against the
+ * current timestamp in the inode and the current time. Returns true
+ * if the inode's timestamp needs to be updated, and false otherwise.
+ * @cb may also be changed if the timestamp needs to be clamped.
+ */
+static bool set_cb_time(struct timespec64 *cb, const struct timespec64 *orig,
+			const struct timespec64 *now)
+{
+
+	/*
+	 * "When the time presented is before the original time, then the
+	 *  update is ignored." Also no need to update if there is no change.
+	 */
+	if (timespec64_compare(cb, orig) <= 0)
+		return false;
+
+	/*
+	 * "When the time presented is in the future, the server can either
+	 *  clamp the new time to the current time, or it may
+	 *  return NFS4ERR_DELAY to the client, allowing it to retry."
+	 */
+	if (timespec64_compare(cb, now) > 0) {
+		/* clamp it */
+		*cb = *now;
+	}
+
+	return true;
+}
+
+static int cb_getattr_update_times(struct dentry *dentry, struct nfs4_delegation *dp)
+{
+	struct inode *inode = d_inode(dentry);
+	struct timespec64 now = current_time(inode);
+	struct nfs4_cb_fattr *ncf = &dp->dl_cb_fattr;
+	struct iattr attrs = { };
+	int ret;
+
+	if (deleg_attrs_deleg(dp->dl_type)) {
+		struct timespec64 atime = inode_get_atime(inode);
+		struct timespec64 mtime = inode_get_mtime(inode);
+
+		attrs.ia_atime = ncf->ncf_cb_atime;
+		attrs.ia_mtime = ncf->ncf_cb_mtime;
+
+		if (set_cb_time(&attrs.ia_atime, &atime, &now))
+			attrs.ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
+
+		if (set_cb_time(&attrs.ia_mtime, &mtime, &now)) {
+			attrs.ia_valid |= ATTR_CTIME | ATTR_MTIME | ATTR_MTIME_SET;
+			attrs.ia_ctime = attrs.ia_mtime;
+		}
+	} else {
+		attrs.ia_valid |= ATTR_MTIME | ATTR_CTIME;
+		attrs.ia_mtime = attrs.ia_ctime = now;
+	}
+
+	if (!attrs.ia_valid)
+		return 0;
+
+	attrs.ia_valid |= ATTR_DELEG;
+	inode_lock(inode);
+	ret = notify_change(&nop_mnt_idmap, dentry, &attrs, NULL);
+	inode_unlock(inode);
+	return ret;
+}
+
+/**
  * nfsd4_deleg_getattr_conflict - Recall if GETATTR causes conflict
  * @rqstp: RPC transaction context
  * @dentry: dentry of inode to be checked for a conflict
@@ -9043,7 +9119,6 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
 	struct file_lock_context *ctx;
 	struct nfs4_delegation *dp = NULL;
 	struct file_lease *fl;
-	struct iattr attrs;
 	struct nfs4_cb_fattr *ncf;
 	struct inode *inode = d_inode(dentry);
 
@@ -9105,11 +9180,7 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
 		 * not update the file's metadata with the client's
 		 * modified size
 		 */
-		attrs.ia_mtime = attrs.ia_ctime = current_time(inode);
-		attrs.ia_valid = ATTR_MTIME | ATTR_CTIME | ATTR_DELEG;
-		inode_lock(inode);
-		err = notify_change(&nop_mnt_idmap, dentry, &attrs, NULL);
-		inode_unlock(inode);
+		err = cb_getattr_update_times(dentry, dp);
 		if (err) {
 			status = nfserrno(err);
 			goto out_status;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 5407fd0d464c..2c5c288064b0 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3400,7 +3400,8 @@ static __be32 nfsd4_encode_fattr4_xattr_support(struct xdr_stream *xdr,
 
 #define NFSD_OA_SHARE_ACCESS_WANT	(BIT(OPEN_ARGS_SHARE_ACCESS_WANT_ANY_DELEG)		| \
 					 BIT(OPEN_ARGS_SHARE_ACCESS_WANT_NO_DELEG)		| \
-					 BIT(OPEN_ARGS_SHARE_ACCESS_WANT_CANCEL))
+					 BIT(OPEN_ARGS_SHARE_ACCESS_WANT_CANCEL)		| \
+					 BIT(OPEN_ARGS_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS))
 
 #define NFSD_OA_OPEN_CLAIM	(BIT(OPEN_ARGS_OPEN_CLAIM_NULL)		| \
 				 BIT(OPEN_ARGS_OPEN_CLAIM_PREVIOUS)	| \
@@ -3593,7 +3594,11 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 		if (status)
 			goto out;
 	}
-	if (attrmask[0] & (FATTR4_WORD0_CHANGE | FATTR4_WORD0_SIZE)) {
+	if ((attrmask[0] & (FATTR4_WORD0_CHANGE |
+			    FATTR4_WORD0_SIZE)) ||
+	    (attrmask[1] & (FATTR4_WORD1_TIME_ACCESS |
+			    FATTR4_WORD1_TIME_MODIFY |
+			    FATTR4_WORD1_TIME_METADATA))) {
 		status = nfsd4_deleg_getattr_conflict(rqstp, dentry, &dp);
 		if (status)
 			goto out;
@@ -3608,8 +3613,14 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 		if (ncf->ncf_file_modified) {
 			++ncf->ncf_initial_cinfo;
 			args.stat.size = ncf->ncf_cur_fsize;
+			if (!timespec64_is_epoch(&ncf->ncf_cb_mtime))
+				args.stat.mtime = ncf->ncf_cb_mtime;
 		}
 		args.change_attr = ncf->ncf_initial_cinfo;
+
+		if (!timespec64_is_epoch(&ncf->ncf_cb_atime))
+			args.stat.atime = ncf->ncf_cb_atime;
+
 		nfs4_put_stid(&dp->dl_stid);
 	} else {
 		args.change_attr = nfsd4_change_attribute(&args.stat);
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 988df43f6b07..4c101c8be95f 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -456,6 +456,8 @@ enum {
 	FATTR4_WORD2_MODE_UMASK | \
 	NFSD4_2_SECURITY_ATTRS | \
 	FATTR4_WORD2_XATTR_SUPPORT | \
+	FATTR4_WORD2_TIME_DELEG_ACCESS | \
+	FATTR4_WORD2_TIME_DELEG_MODIFY | \
 	FATTR4_WORD2_OPEN_ARGUMENTS)
 
 extern const u32 nfsd_suppattrs[3][3];
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 17e98a2521ff..74d2d7b42676 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -159,6 +159,8 @@ struct nfs4_cb_fattr {
 	/* from CB_GETATTR reply */
 	u64 ncf_cb_change;
 	u64 ncf_cb_fsize;
+	struct timespec64 ncf_cb_mtime;
+	struct timespec64 ncf_cb_atime;
 
 	unsigned long ncf_cb_flags;
 	bool ncf_file_modified;
diff --git a/fs/nfsd/xdr4cb.h b/fs/nfsd/xdr4cb.h
index e8b00309c449..f1a315cd31b7 100644
--- a/fs/nfsd/xdr4cb.h
+++ b/fs/nfsd/xdr4cb.h
@@ -59,16 +59,20 @@
  * 1: CB_GETATTR opcode (32-bit)
  * N: file_handle
  * 1: number of entry in attribute array (32-bit)
- * 1: entry 0 in attribute array (32-bit)
+ * 3: entry 0-2 in attribute array (32-bit * 3)
  */
 #define NFS4_enc_cb_getattr_sz		(cb_compound_enc_hdr_sz +       \
 					cb_sequence_enc_sz +            \
-					1 + enc_nfs4_fh_sz + 1 + 1)
+					1 + enc_nfs4_fh_sz + 1 + 3)
 /*
  * 4: fattr_bitmap_maxsz
  * 1: attribute array len
  * 2: change attr (64-bit)
  * 2: size (64-bit)
+ * 2: atime.seconds (64-bit)
+ * 1: atime.nanoseconds (32-bit)
+ * 2: mtime.seconds (64-bit)
+ * 1: mtime.nanoseconds (32-bit)
  */
 #define NFS4_dec_cb_getattr_sz		(cb_compound_dec_hdr_sz  +      \
-			cb_sequence_dec_sz + 4 + 1 + 2 + 2 + op_dec_sz)
+			cb_sequence_dec_sz + 4 + 1 + 2 + 2 + 2 + 1 + 2 + 1 + op_dec_sz)
diff --git a/include/linux/time64.h b/include/linux/time64.h
index f1bcea8c124a..9934331c7b86 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -49,6 +49,11 @@ static inline int timespec64_equal(const struct timespec64 *a,
 	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
 }
 
+static inline bool timespec64_is_epoch(const struct timespec64 *ts)
+{
+	return ts->tv_sec == 0 && ts->tv_nsec == 0;
+}
+
 /*
  * lhs < rhs:  return <0
  * lhs == rhs: return 0