Allow batching of forget requests

This allows forget requests to be processed faster and doesn't require
a modification to fuse filesystems.  Reported by Terje Malmedal

4 files changed, 80 insertions, 13 deletions

diff --git a/ChangeLog b/ChangeLog
index f836222..ef22dd1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -46,6 +46,12 @@
 	* Highlevel lib: use dynamically resized hash table for looking up
 	by name and node ID.
 
+2010-12-07  Miklos Szeredi <miklos@szeredi.hu>
+
+	* Allow batching of forget requests.  This allows forget requests
+	to be processed faster and doesn't require a modification to fuse
+	filesystems.  Reported by Terje Malmedal
+
 2010-11-10  Miklos Szeredi <miklos@szeredi.hu>
 
 	* Add new write_buf() method to the highlevel API.  Similarly to
diff --git a/include/fuse_kernel.h b/include/fuse_kernel.h
index c7c99a5..7e7ca17 100644
--- a/include/fuse_kernel.h
+++ b/include/fuse_kernel.h
@@ -67,6 +67,9 @@
  * 7.15
  *  - add store notify
  *  - add retrieve notify
+ *
+ * 7.16
+ *  - add BATCH_FORGET request
  */
 
 #ifndef _LINUX_FUSE_H
@@ -103,7 +106,7 @@
 #define FUSE_KERNEL_VERSION 7
 
 /** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 15
+#define FUSE_KERNEL_MINOR_VERSION 16
 
 /** The node ID of the root inode */
 #define FUSE_ROOT_ID 1
@@ -287,6 +290,7 @@ enum fuse_opcode {
 	FUSE_IOCTL         = 39,
 	FUSE_POLL          = 40,
 	FUSE_NOTIFY_REPLY  = 41,
+	FUSE_BATCH_FORGET  = 42,
 
 	/* CUSE specific operations */
 	CUSE_INIT          = 4096,
@@ -321,6 +325,16 @@ struct fuse_forget_in {
 	__u64	nlookup;
 };
 
+struct fuse_forget_one {
+	__u64	nodeid;
+	__u64	nlookup;
+};
+
+struct fuse_batch_forget_in {
+	__u32	count;
+	__u32	dummy;
+};
+
 struct fuse_getattr_in {
 	__u32	getattr_flags;
 	__u32	dummy;
diff --git a/lib/fuse_loop_mt.c b/lib/fuse_loop_mt.c
index 694f98c..ab5fd11 100644
--- a/lib/fuse_loop_mt.c
+++ b/lib/fuse_loop_mt.c
@@ -99,9 +99,13 @@ static void *fuse_do_work(void *data)
 		 * This disgusting hack is needed so that zillions of threads
 		 * are not created on a burst of FORGET messages
 		 */
-		if (!(fbuf.flags & FUSE_BUF_IS_FD) &&
-		    ((struct fuse_in_header *) fbuf.mem)->opcode == FUSE_FORGET)
-			isforget = 1;
+		if (!(fbuf.flags & FUSE_BUF_IS_FD)) {
+			struct fuse_in_header *in = fbuf.mem;
+
+			if (in->opcode == FUSE_FORGET ||
+			    in->opcode == FUSE_BATCH_FORGET)
+				isforget = 1;
+		}
 
 		if (!isforget)
 			mt->numavail--;
diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index 55bce2b..4643a8a 100644
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -137,6 +137,24 @@ void fuse_free_req(fuse_req_t req)
 		destroy_req(req);
 }
 
+static struct fuse_req *fuse_ll_alloc_req(struct fuse_ll *f)
+{
+	struct fuse_req *req;
+
+	req = (struct fuse_req *) calloc(1, sizeof(struct fuse_req));
+	if (req == NULL) {
+		fprintf(stderr, "fuse: failed to allocate request\n");
+	} else {
+		req->f = f;
+		req->ctr = 1;
+		list_init_req(req);
+		fuse_mutex_init(&req->lock);
+	}
+
+	return req;
+}
+
+
 static int fuse_send_msg(struct fuse_ll *f, struct fuse_chan *ch,
 			 struct iovec *iov, int count)
 {
@@ -284,7 +302,8 @@ int fuse_reply_err(fuse_req_t req, int err)
 
 void fuse_reply_none(fuse_req_t req)
 {
-	fuse_chan_send(req->ch, NULL, 0);
+	if (req->ch)
+		fuse_chan_send(req->ch, NULL, 0);
 	fuse_free_req(req);
 }
 
@@ -878,6 +897,35 @@ static void do_forget(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 		fuse_reply_none(req);
 }
 
+static void do_batch_forget(fuse_req_t req, fuse_ino_t nodeid,
+			    const void *inarg)
+{
+	struct fuse_batch_forget_in *arg = (void *) inarg;
+	struct fuse_forget_one *param = (void *) PARAM(arg);
+	unsigned int i;
+
+	(void) nodeid;
+
+	if (req->f->op.forget) {
+		for (i = 0; i < arg->count; i++) {
+			struct fuse_forget_one *forget = &param[i];
+			struct fuse_req *dummy_req;
+
+			dummy_req = fuse_ll_alloc_req(req->f);
+			if (dummy_req == NULL)
+				break;
+
+			dummy_req->unique = req->unique;
+			dummy_req->ctx = req->ctx;
+			dummy_req->ch = NULL;
+
+			req->f->op.forget(dummy_req, forget->nodeid,
+					  forget->nlookup);
+		}
+	}
+	fuse_reply_none(req);
+}
+
 static void do_getattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 {
 	struct fuse_file_info *fip = NULL;
@@ -2035,6 +2083,7 @@ static struct {
 	[FUSE_POLL]	   = { do_poll,        "POLL"	     },
 	[FUSE_DESTROY]	   = { do_destroy,     "DESTROY"     },
 	[FUSE_NOTIFY_REPLY] = { (void *) 1,    "NOTIFY_REPLY" },
+	[FUSE_BATCH_FORGET] = { do_batch_forget, "BATCH_FORGET" },
 	[CUSE_INIT]	   = { cuse_lowlevel_init, "CUSE_INIT"   },
 };
 
@@ -2098,21 +2147,15 @@ static void fuse_ll_process_buf(void *data, const struct fuse_buf *buf,
 		in = buf->mem;
 	}
 
-	req = (struct fuse_req *) calloc(1, sizeof(struct fuse_req));
-	if (req == NULL) {
-		fprintf(stderr, "fuse: failed to allocate request\n");
+	req = fuse_ll_alloc_req(f);
+	if (req == NULL)
 		goto clear_pipe;
-	}
 
-	req->f = f;
 	req->unique = in->unique;
 	req->ctx.uid = in->uid;
 	req->ctx.gid = in->gid;
 	req->ctx.pid = in->pid;
 	req->ch = ch;
-	req->ctr = 1;
-	list_init_req(req);
-	fuse_mutex_init(&req->lock);
 
 	if (f->debug)
 		fprintf(stderr,