fuse: add helper for asynchronous writes

This patch adds a new helper function fuse_write_fill() which makes it possible to send WRITE requests asynchronously. A new flag for WRITE requests is also added which indicates that this a write from the page cache, and not a "normal" file write. This patch is in preparation for writable mmap support. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fuse: add helper for asynchronous writes
This patch adds a new helper function fuse_write_fill() which makes it possible to send WRITE requests asynchronously. A new flag for WRITE requests is also added which indicates that this a write from the page cache, and not a "normal" file write. This patch is in preparation for writable mmap support. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miklos Szeredi · Linus Torvalds
1 parent 93a8c3cd9e
Showing 3 changed files with 31 additions and 13 deletions Side-by-side Diff
fs/fuse/file.c
fs/fuse/fuse_i.h
include/linux/fuse.h
@@ -443,30 +443,37 @@
 	return err;
 }
  
-static size_t fuse_send_write(struct fuse_req *req, struct file *file,
-			      struct inode *inode, loff_t pos, size_t count)
+static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
+			    struct inode *inode, loff_t pos, size_t count,
+			    int writepage)
 {
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_file *ff = file->private_data;
-	struct fuse_write_in inarg;
-	struct fuse_write_out outarg;
+	struct fuse_write_in *inarg = &req->misc.write.in;
+	struct fuse_write_out *outarg = &req->misc.write.out;
  
-	memset(&inarg, 0, sizeof(struct fuse_write_in));
-	inarg.fh = ff->fh;
-	inarg.offset = pos;
-	inarg.size = count;
+	memset(inarg, 0, sizeof(struct fuse_write_in));
+	inarg->fh = ff->fh;
+	inarg->offset = pos;
+	inarg->size = count;
+	inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
 	req->in.h.opcode = FUSE_WRITE;
 	req->in.h.nodeid = get_node_id(inode);
 	req->in.argpages = 1;
 	req->in.numargs = 2;
 	req->in.args[0].size = sizeof(struct fuse_write_in);
-	req->in.args[0].value = &inarg;
+	req->in.args[0].value = inarg;
 	req->in.args[1].size = count;
 	req->out.numargs = 1;
 	req->out.args[0].size = sizeof(struct fuse_write_out);
-	req->out.args[0].value = &outarg;
+	req->out.args[0].value = outarg;
+}
+
+static size_t fuse_send_write(struct fuse_req *req, struct file *file,
+			      struct inode *inode, loff_t pos, size_t count)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	fuse_write_fill(req, file->private_data, inode, pos, count, 0);
 	request_send(fc, req);
-	return outarg.size;
+	return req->misc.write.out.size;
 }
  
 static int fuse_write_begin(struct file *file, struct address_space *mapping,
@@ -219,6 +219,10 @@
 		struct fuse_init_in init_in;
 		struct fuse_init_out init_out;
 		struct fuse_read_in read_in;
+		struct {
+			struct fuse_write_in in;
+			struct fuse_write_out out;
+		} write;
 		struct fuse_lk_in lk_in;
 	} misc;
  
@@ -119,6 +119,13 @@
  */
 #define FUSE_LK_FLOCK		(1 << 0)
  
+/**
+ * WRITE flags
+ *
+ * FUSE_WRITE_CACHE: delayed write from page cache, file handle is guessed
+ */
+#define FUSE_WRITE_CACHE	(1 << 0)
+
 enum fuse_opcode {
 	FUSE_LOOKUP	   = 1,
 	FUSE_FORGET	   = 2,  /* no reply */
...	...	@@ -443,30 +443,37 @@
443	443	return err;
444	444	}
445	445
446		-static size_t fuse_send_write(struct fuse_req req, struct file file,
447		- struct inode *inode, loff_t pos, size_t count)
	446	+static void fuse_write_fill(struct fuse_req req, struct fuse_file ff,
	447	+ struct inode *inode, loff_t pos, size_t count,
	448	+ int writepage)
448	449	{
449		- struct fuse_conn *fc = get_fuse_conn(inode);
450		- struct fuse_file *ff = file->private_data;
451		- struct fuse_write_in inarg;
452		- struct fuse_write_out outarg;
	450	+ struct fuse_write_in *inarg = &req->misc.write.in;
	451	+ struct fuse_write_out *outarg = &req->misc.write.out;
453	452
454		- memset(&inarg, 0, sizeof(struct fuse_write_in));
455		- inarg.fh = ff->fh;
456		- inarg.offset = pos;
457		- inarg.size = count;
	453	+ memset(inarg, 0, sizeof(struct fuse_write_in));
	454	+ inarg->fh = ff->fh;
	455	+ inarg->offset = pos;
	456	+ inarg->size = count;
	457	+ inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
458	458	req->in.h.opcode = FUSE_WRITE;
459	459	req->in.h.nodeid = get_node_id(inode);
460	460	req->in.argpages = 1;
461	461	req->in.numargs = 2;
462	462	req->in.args[0].size = sizeof(struct fuse_write_in);
463		- req->in.args[0].value = &inarg;
	463	+ req->in.args[0].value = inarg;
464	464	req->in.args[1].size = count;
465	465	req->out.numargs = 1;
466	466	req->out.args[0].size = sizeof(struct fuse_write_out);
467		- req->out.args[0].value = &outarg;
	467	+ req->out.args[0].value = outarg;
	468	+}
	469	+
	470	+static size_t fuse_send_write(struct fuse_req req, struct file file,
	471	+ struct inode *inode, loff_t pos, size_t count)
	472	+{
	473	+ struct fuse_conn *fc = get_fuse_conn(inode);
	474	+ fuse_write_fill(req, file->private_data, inode, pos, count, 0);
468	475	request_send(fc, req);
469		- return outarg.size;
	476	+ return req->misc.write.out.size;
470	477	}
471	478
472	479	static int fuse_write_begin(struct file file, struct address_space mapping,
...	...	@@ -219,6 +219,10 @@
219	219	struct fuse_init_in init_in;
220	220	struct fuse_init_out init_out;
221	221	struct fuse_read_in read_in;
	222	+ struct {
	223	+ struct fuse_write_in in;
	224	+ struct fuse_write_out out;
	225	+ } write;
222	226	struct fuse_lk_in lk_in;
223	227	} misc;
224	228
...	...	@@ -119,6 +119,13 @@
119	119	*/
120	120	#define FUSE_LK_FLOCK (1 << 0)
121	121
	122	+/**
	123	+ * WRITE flags
	124	+ *
	125	+ * FUSE_WRITE_CACHE: delayed write from page cache, file handle is guessed
	126	+ */
	127	+#define FUSE_WRITE_CACHE (1 << 0)
	128	+
122	129	enum fuse_opcode {
123	130	FUSE_LOOKUP = 1,
124	131	FUSE_FORGET = 2, /* no reply */