[PATCH v7 20/20] nfsd: add support to CB_NOTIFY for dir attribute changes

[Jeff Layton <jlayton@kernel.org>]

If the client requested dir attribute change notifications, send those
alongside any set of add/remove/rename events. Note that the server will
still recall the delegation on a SETATTR, so these are only sent for
changes to child dirents.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 Documentation/sunrpc/xdr/nfs4_1.x |  1 +
 fs/nfsd/nfs4proc.c                |  7 +++--
 fs/nfsd/nfs4state.c               | 25 +++++++++++++++--
 fs/nfsd/nfs4xdr.c                 | 58 +++++++++++++++++++++++++++++++++------
 fs/nfsd/nfs4xdr_gen.c             |  4 +--
 fs/nfsd/nfs4xdr_gen.h             |  3 ++
 fs/nfsd/xdr4.h                    |  2 ++
 7 files changed, 84 insertions(+), 16 deletions(-)

diff --git a/Documentation/sunrpc/xdr/nfs4_1.x b/Documentation/sunrpc/xdr/nfs4_1.x
index a32df1e882e5..e66f396ae659 100644
--- a/Documentation/sunrpc/xdr/nfs4_1.x
+++ b/Documentation/sunrpc/xdr/nfs4_1.x
@@ -464,6 +464,7 @@ pragma public notify_add4;
 struct notify_attr4 {
         notify_entry4   na_changed_entry;
 };
+pragma public notify_attr4;
 
 struct notify_rename4 {
         notify_remove4  nrn_old_entry;
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 48fc7b0df4dc..c413ed0810b9 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2552,9 +2552,10 @@ nfsd4_verify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	return status == nfserr_same ? nfs_ok : status;
 }
 
-#define SUPPORTED_NOTIFY_MASK	(BIT(NOTIFY4_REMOVE_ENTRY) |	\
-				 BIT(NOTIFY4_ADD_ENTRY) |	\
-				 BIT(NOTIFY4_RENAME_ENTRY) |	\
+#define SUPPORTED_NOTIFY_MASK	(BIT(NOTIFY4_CHANGE_DIR_ATTRS) |	\
+				 BIT(NOTIFY4_REMOVE_ENTRY) |		\
+				 BIT(NOTIFY4_ADD_ENTRY) |		\
+				 BIT(NOTIFY4_RENAME_ENTRY) |		\
 				 BIT(NOTIFY4_GFLAG_EXTEND))
 
 static __be32
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a948dc8a46cc..2f7210accdf1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3522,10 +3522,15 @@ nfsd4_cb_notify_prepare(struct nfsd4_callback *cb)
 	struct nfsd_notify_event *events[NOTIFY4_EVENT_QUEUE_SIZE];
 	struct xdr_buf xdr = { .buflen = PAGE_SIZE * NOTIFY4_PAGE_ARRAY_SIZE,
 			       .pages  = ncn->ncn_pages };
+	int limit = NOTIFY4_EVENT_QUEUE_SIZE;
 	struct xdr_stream stream;
 	struct nfsd_file *nf;
-	int count, i;
 	bool error = false;
+	int count, i;
+
+	/* Save a slot for dir attr update if requested */
+	if (dp->dl_notify_mask & BIT(NOTIFY4_CHANGE_DIR_ATTRS))
+		--limit;
 
 	/* Clear any failure recorded by a previous transmit. */
 	ncn->ncn_encode_err = false;
@@ -3542,7 +3547,7 @@ nfsd4_cb_notify_prepare(struct nfsd4_callback *cb)
 	}
 
 	/* we can't keep up! */
-	if (count > NOTIFY4_EVENT_QUEUE_SIZE) {
+	if (count > limit) {
 		spin_unlock(&ncn->ncn_lock);
 		goto out_recall;
 	}
@@ -3589,6 +3594,22 @@ nfsd4_cb_notify_prepare(struct nfsd4_callback *cb)
 		nfsd_notify_event_put(nne);
 	}
 	if (!error) {
+		if (dp->dl_notify_mask & BIT(NOTIFY4_CHANGE_DIR_ATTRS)) {
+			u32 *maskp = (u32 *)xdr_reserve_space(&stream, sizeof(*maskp));
+
+			if (maskp) {
+				u8 *p = nfsd4_encode_dir_attr_change(&stream, dp, nf);
+
+				if (p) {
+					*maskp = BIT(NOTIFY4_CHANGE_DIR_ATTRS);
+					ncn->ncn_nf[count].notify_mask.count = 1;
+					ncn->ncn_nf[count].notify_mask.element = maskp;
+					ncn->ncn_nf[count].notify_vals.data = p;
+					ncn->ncn_nf[count].notify_vals.len = (u8 *)stream.p - p;
+					++count;
+				}
+			}
+		}
 		ncn->ncn_nf_cnt = count;
 		nfsd_file_put(nf);
 		return true;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 0649bb4cf2e7..a18d0b766b50 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -4253,11 +4253,11 @@ nfsd4_setup_notify_entry4(struct notify_entry4 *ne, struct xdr_stream *xdr,
 			  struct dentry *dentry, struct nfs4_delegation *dp,
 			  struct nfsd_file *nf, char *name, u32 namelen)
 {
-	struct path path =  { .mnt = nf->nf_file->f_path.mnt,
-			      .dentry = dentry };
+	struct path path = nf->nf_file->f_path;
 	struct nfsd4_fattr_args args = { };
 	uint32_t *attrmask;
 	__be32 status;
+	bool parent;
 	int ret;
 
 	/* Reserve space for attrmask */
@@ -4269,6 +4269,9 @@ nfsd4_setup_notify_entry4(struct notify_entry4 *ne, struct xdr_stream *xdr,
 	ne->ne_file.len = namelen;
 	ne->ne_attrs.attrmask.element = attrmask;
 
+	parent = (dentry == path.dentry);
+	path.dentry = dentry;
+
 	/* FIXME: d_find_alias for inode ? */
 	if (!path.dentry || !d_inode(path.dentry))
 		goto noattrs;
@@ -4284,15 +4287,20 @@ nfsd4_setup_notify_entry4(struct notify_entry4 *ne, struct xdr_stream *xdr,
 
 	args.change_attr = nfsd4_change_attribute(&args.stat);
 
-	attrmask[0] = dp->dl_child_attrs[0];
-	attrmask[1] = dp->dl_child_attrs[1];
-	attrmask[2] = 0;
+	if (parent) {
+		attrmask[0] = dp->dl_dir_attrs[0];
+		attrmask[1] = dp->dl_dir_attrs[1];
+	} else {
+		attrmask[0] = dp->dl_child_attrs[0];
+		attrmask[1] = dp->dl_child_attrs[1];
 
-	if (!setup_notify_fhandle(dentry, dp, nf, &args))
-		attrmask[0] &= ~FATTR4_WORD0_FILEHANDLE;
+		if (!setup_notify_fhandle(dentry, dp, nf, &args))
+			attrmask[0] &= ~FATTR4_WORD0_FILEHANDLE;
 
-	if (!(args.stat.result_mask & STATX_BTIME))
-		attrmask[1] &= ~FATTR4_WORD1_TIME_CREATE;
+		if (!(args.stat.result_mask & STATX_BTIME))
+			attrmask[1] &= ~FATTR4_WORD1_TIME_CREATE;
+	}
+	attrmask[2] = 0;
 
 	ne->ne_attrs.attrmask.count = 2;
 	ne->ne_attrs.attr_vals.data = (u8 *)xdr->p;
@@ -4405,6 +4413,38 @@ u8 *nfsd4_encode_notify_event(struct xdr_stream *xdr, struct nfsd_notify_event *
 	return NULL;
 }
 
+/**
+ * nfsd4_encode_dir_attr_change
+ * @xdr: stream to which to encode the fattr4
+ * @dp: delegation where the event occurred
+ * @nf: nfsd_file opened on the directory
+ *
+ * Encode a dir attr change event.
+ */
+u8 *nfsd4_encode_dir_attr_change(struct xdr_stream *xdr, struct nfs4_delegation *dp,
+				 struct nfsd_file *nf)
+{
+	struct dentry *dentry = nf->nf_file->f_path.dentry;
+	struct notify_attr4 na = { };
+	bool ret;
+	u8 *p = NULL;
+
+	if (!(dp->dl_notify_mask & BIT(NOTIFY4_CHANGE_DIR_ATTRS)))
+		return NULL;
+
+	/* RFC 8881 s10.4.3: ne_file must be a zero-length string for dir attrs */
+	ret = nfsd4_setup_notify_entry4(&na.na_changed_entry, xdr,
+					dentry, dp, nf, "", 0);
+
+	/* Don't bother with the event if we're not encoding attrs */
+	if (ret && na.na_changed_entry.ne_attrs.attr_vals.len) {
+		p = (u8 *)xdr->p;
+		if (!xdrgen_encode_notify_attr4(xdr, &na))
+			p = NULL;
+	}
+	return p;
+}
+
 static void svcxdr_init_encode_from_buffer(struct xdr_stream *xdr,
 				struct xdr_buf *buf, __be32 *p, int bytes)
 {
diff --git a/fs/nfsd/nfs4xdr_gen.c b/fs/nfsd/nfs4xdr_gen.c
index d1240ade120d..a6725c773768 100644
--- a/fs/nfsd/nfs4xdr_gen.c
+++ b/fs/nfsd/nfs4xdr_gen.c
@@ -669,7 +669,7 @@ xdrgen_decode_notify_add4(struct xdr_stream *xdr, struct notify_add4 *ptr)
 	return true;
 }
 
-static bool __maybe_unused
+bool
 xdrgen_decode_notify_attr4(struct xdr_stream *xdr, struct notify_attr4 *ptr)
 {
 	if (!xdrgen_decode_notify_entry4(xdr, &ptr->na_changed_entry))
@@ -1091,7 +1091,7 @@ xdrgen_encode_notify_add4(struct xdr_stream *xdr, const struct notify_add4 *valu
 	return true;
 }
 
-static bool __maybe_unused
+bool
 xdrgen_encode_notify_attr4(struct xdr_stream *xdr, const struct notify_attr4 *value)
 {
 	if (!xdrgen_encode_notify_entry4(xdr, &value->na_changed_entry))
diff --git a/fs/nfsd/nfs4xdr_gen.h b/fs/nfsd/nfs4xdr_gen.h
index c62299bac735..f6a458a07406 100644
--- a/fs/nfsd/nfs4xdr_gen.h
+++ b/fs/nfsd/nfs4xdr_gen.h
@@ -38,6 +38,9 @@ bool xdrgen_encode_notify_remove4(struct xdr_stream *xdr, const struct notify_re
 bool xdrgen_decode_notify_add4(struct xdr_stream *xdr, struct notify_add4 *ptr);
 bool xdrgen_encode_notify_add4(struct xdr_stream *xdr, const struct notify_add4 *value);
 
+bool xdrgen_decode_notify_attr4(struct xdr_stream *xdr, struct notify_attr4 *ptr);
+bool xdrgen_encode_notify_attr4(struct xdr_stream *xdr, const struct notify_attr4 *value);
+
 bool xdrgen_decode_notify_rename4(struct xdr_stream *xdr, struct notify_rename4 *ptr);
 bool xdrgen_encode_notify_rename4(struct xdr_stream *xdr, const struct notify_rename4 *value);
 
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 62ac790428be..805c7122eb93 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -973,6 +973,8 @@ __be32 nfsd4_encode_fattr_to_buf(__be32 **p, int words,
 u8 *nfsd4_encode_notify_event(struct xdr_stream *xdr, struct nfsd_notify_event *nne,
 			      struct nfs4_delegation *dd, struct nfsd_file *nf,
 			      u32 *notify_mask);
+u8 *nfsd4_encode_dir_attr_change(struct xdr_stream *xdr, struct nfs4_delegation *dp,
+				 struct nfsd_file *nf);
 extern __be32 nfsd4_setclientid(struct svc_rqst *rqstp,
 		struct nfsd4_compound_state *, union nfsd4_op_u *u);
 extern __be32 nfsd4_setclientid_confirm(struct svc_rqst *rqstp,

-- 
2.54.0