[patch 10/12] fuse: add helper for asynchronous writes

Miklos Szeredi
2007-10-02T15:53:54Z

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From: Miklos Szeredi <mszeredi@suse.cz>

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>
---

Index: linux/fs/fuse/file.c
===================================================================
--- linux.orig/fs/fuse/file.c 2007-09-25 21:19:14.000000000 +0200
+++ linux/fs/fuse/file.c 2007-09-25 21:19:15.000000000 +0200
@@ -443,30 +443,37 @@ out:
return err;
}

-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);
- struct fuse_file *ff = file->private_data;
- struct fuse_write_in inarg;
- struct fuse_write_out outarg;
-
- memset(&inarg, 0, sizeof(struct fuse_write_in));
- inarg.fh = ff->fh;
- inarg.offset = pos;
- inarg.size = 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_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;
+ 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,
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h 2007-09-25 21:19:14.000000000 +0200
+++ linux/fs/fuse/fuse_i.h 2007-09-25 21:19:15.000000000 +0200
@@ -219,6 +219,10 @@ struct fuse_req {
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;

Index: linux/include/linux/fuse.h
===================================================================
--- linux.orig/include/linux/fuse.h 2007-09-25 21:19:14.000000000 +0200
+++ linux/include/linux/fuse.h 2007-09-25 21:19:15.000000000 +0200
@@ -119,6 +119,13 @@ struct fuse_file_lock {
*/
#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 */

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