glusterfs: discard (hole punch) support

Add support for the DISCARD file operation. Discard punches a hole
in a file in the provided range. Block de-allocation is implemented
via fallocate() (as requested via fuse and passed on to the brick
fs) but a separate fop is created within gluster to emphasize the
fact that discard changes file data (the discarded region is
replaced with zeroes) and must invalidate caches where appropriate.

BUG: 963678
Change-Id: I34633a0bfff2187afeab4292a15f3cc9adf261af
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-on: http://review.gluster.org/5090
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

3 files changed, 82 insertions, 0 deletions

diff --git a/rpc/xdr/src/glusterfs3-xdr.c b/rpc/xdr/src/glusterfs3-xdr.c
index 2ce0b84ede9..4e9791b2077 100644
--- a/rpc/xdr/src/glusterfs3-xdr.c
+++ b/rpc/xdr/src/glusterfs3-xdr.c
@@ -1547,6 +1547,44 @@ xdr_gfs3_fallocate_rsp (XDR *xdrs, gfs3_fallocate_rsp *objp)
 }
 
 bool_t
+xdr_gfs3_discard_req (XDR *xdrs, gfs3_discard_req *objp)
+{
+	register int32_t *buf;
+        buf = NULL;
+
+	 if (!xdr_opaque (xdrs, objp->gfid, 16))
+		 return FALSE;
+	 if (!xdr_quad_t (xdrs, &objp->fd))
+		 return FALSE;
+	 if (!xdr_u_quad_t (xdrs, &objp->offset))
+		 return FALSE;
+	 if (!xdr_u_quad_t (xdrs, &objp->size))
+		 return FALSE;
+	 if (!xdr_bytes (xdrs, (char **)&objp->xdata.xdata_val, (u_int *) &objp->xdata.xdata_len, ~0))
+		 return FALSE;
+	return TRUE;
+}
+
+bool_t
+xdr_gfs3_discard_rsp (XDR *xdrs, gfs3_discard_rsp *objp)
+{
+	register int32_t *buf;
+        buf = NULL;
+
+	 if (!xdr_int (xdrs, &objp->op_ret))
+		 return FALSE;
+	 if (!xdr_int (xdrs, &objp->op_errno))
+		 return FALSE;
+	 if (!xdr_gf_iatt (xdrs, &objp->statpre))
+		 return FALSE;
+	 if (!xdr_gf_iatt (xdrs, &objp->statpost))
+		 return FALSE;
+	 if (!xdr_bytes (xdrs, (char **)&objp->xdata.xdata_val, (u_int *) &objp->xdata.xdata_len, ~0))
+		 return FALSE;
+	return TRUE;
+}
+
+bool_t
 xdr_gfs3_rchecksum_req (XDR *xdrs, gfs3_rchecksum_req *objp)
 {
 	register int32_t *buf;
diff --git a/rpc/xdr/src/glusterfs3-xdr.h b/rpc/xdr/src/glusterfs3-xdr.h
index 2f9ba4b4552..9e5d2e67bcb 100644
--- a/rpc/xdr/src/glusterfs3-xdr.h
+++ b/rpc/xdr/src/glusterfs3-xdr.h
@@ -912,6 +912,30 @@ struct gfs3_fallocate_rsp {
 };
 typedef struct gfs3_fallocate_rsp gfs3_fallocate_rsp;
 
+struct gfs3_discard_req {
+	char gfid[16];
+	quad_t fd;
+	u_quad_t offset;
+	u_quad_t size;
+	struct {
+		u_int xdata_len;
+		char *xdata_val;
+	} xdata;
+};
+typedef struct gfs3_discard_req gfs3_discard_req;
+
+struct gfs3_discard_rsp {
+	int op_ret;
+	int op_errno;
+	struct gf_iatt statpre;
+	struct gf_iatt statpost;
+	struct {
+		u_int xdata_len;
+		char *xdata_val;
+	} xdata;
+};
+typedef struct gfs3_discard_rsp gfs3_discard_rsp;
+
 struct gfs3_rchecksum_req {
 	quad_t fd;
 	u_quad_t offset;
@@ -1209,6 +1233,8 @@ extern  bool_t xdr_gfs3_fsetattr_req (XDR *, gfs3_fsetattr_req*);
 extern  bool_t xdr_gfs3_fsetattr_rsp (XDR *, gfs3_fsetattr_rsp*);
 extern  bool_t xdr_gfs3_fallocate_req (XDR *, gfs3_fallocate_req*);
 extern  bool_t xdr_gfs3_fallocate_rsp (XDR *, gfs3_fallocate_rsp*);
+extern  bool_t xdr_gfs3_discard_req (XDR *, gfs3_discard_req*);
+extern  bool_t xdr_gfs3_discard_rsp (XDR *, gfs3_discard_rsp*);
 extern  bool_t xdr_gfs3_rchecksum_req (XDR *, gfs3_rchecksum_req*);
 extern  bool_t xdr_gfs3_rchecksum_rsp (XDR *, gfs3_rchecksum_rsp*);
 extern  bool_t xdr_gf_setvolume_req (XDR *, gf_setvolume_req*);
@@ -1305,6 +1331,8 @@ extern bool_t xdr_gfs3_fsetattr_req ();
 extern bool_t xdr_gfs3_fsetattr_rsp ();
 extern bool_t xdr_gfs3_fallocate_req ();
 extern bool_t xdr_gfs3_fallocate_rsp ();
+extern bool_t xdr_gfs3_discard_req ();
+extern bool_t xdr_gfs3_discard_rsp ();
 extern bool_t xdr_gfs3_rchecksum_req ();
 extern bool_t xdr_gfs3_rchecksum_rsp ();
 extern bool_t xdr_gf_setvolume_req ();
diff --git a/rpc/xdr/src/glusterfs3-xdr.x b/rpc/xdr/src/glusterfs3-xdr.x
index 7fad58336a6..e2b086b1d1a 100644
--- a/rpc/xdr/src/glusterfs3-xdr.x
+++ b/rpc/xdr/src/glusterfs3-xdr.x
@@ -583,6 +583,22 @@ struct gfs3_fstat_req {
         opaque   xdata<>; /* Extra data */
 }  ;
 
+ struct gfs3_discard_req {
+	opaque		gfid[16];
+        hyper		fd;
+	unsigned hyper	offset;
+	unsigned hyper	size;
+        opaque   xdata<>; /* Extra data */
+}  ;
+
+ struct gfs3_discard_rsp {
+        int    op_ret;
+        int    op_errno;
+        struct gf_iatt statpre;
+        struct gf_iatt statpost;
+        opaque   xdata<>; /* Extra data */
+}  ;
+
  struct gfs3_rchecksum_req {
         hyper   fd;
         unsigned hyper  offset;