[PATCH] FUSE: add fsync operation for directories

This patch adds a new FSYNCDIR request, which is sent when fsync is called
on directories.  This operation is available in libfuse 2.3-pre1 or
greater.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/fuse/dir.c

@@ -617,6 +617,12 @@ static int fuse_dir_release(struct inode *inode, struct file *file)
 	return fuse_release_common(inode, file, 1);
 }
 
+static int fuse_dir_fsync(struct file *file, struct dentry *de, int datasync)
+{
+	/* nfsd can call this with no file */
+	return file ? fuse_fsync_common(file, de, datasync, 1) : 0;
+}
+
 static unsigned iattr_to_fattr(struct iattr *iattr, struct fuse_attr *fattr)
 {
 	unsigned ivalid = iattr->ia_valid;
@@ -934,6 +940,7 @@ static struct file_operations fuse_dir_operations = {
 	.readdir	= fuse_readdir,
 	.open		= fuse_dir_open,
 	.release	= fuse_dir_release,
+	.fsync		= fuse_dir_fsync,
 };
 
 static struct inode_operations fuse_common_inode_operations = {

fs/fuse/file.c

@@ -156,7 +156,8 @@ static int fuse_flush(struct file *file)
 	return err;
 }
 
-static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
+int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
+		      int isdir)
 {
 	struct inode *inode = de->d_inode;
 	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -165,7 +166,7 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 	struct fuse_fsync_in inarg;
 	int err;
 
-	if (fc->no_fsync)
+	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 		return 0;
 
 	req = fuse_get_request(fc);
@@ -175,7 +176,7 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.fh = ff->fh;
 	inarg.fsync_flags = datasync ? 1 : 0;
-	req->in.h.opcode = FUSE_FSYNC;
+	req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 	req->in.h.nodeid = get_node_id(inode);
 	req->inode = inode;
 	req->file = file;
@@ -186,12 +187,20 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 	err = req->out.h.error;
 	fuse_put_request(fc, req);
 	if (err == -ENOSYS) {
-		fc->no_fsync = 1;
+		if (isdir)
+			fc->no_fsyncdir = 1;
+		else
+			fc->no_fsync = 1;
 		err = 0;
 	}
 	return err;
 }
 
+static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
+{
+	return fuse_fsync_common(file, de, datasync, 0);
+}
+
 size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
 			     struct inode *inode, loff_t pos, size_t count,
 			     int isdir)

fs/fuse/fuse_i.h

@@ -248,6 +248,9 @@ struct fuse_conn {
 	/** Is fsync not implemented by fs? */
 	unsigned no_fsync : 1;
 
+	/** Is fsyncdir not implemented by fs? */
+	unsigned no_fsyncdir : 1;
+
 	/** Is flush not implemented by fs? */
 	unsigned no_flush : 1;
 
@@ -339,6 +342,12 @@ int fuse_open_common(struct inode *inode, struct file *file, int isdir);
  */
 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
 
+/**
+ * Send FSYNC or FSYNCDIR request
+ */
+int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
+		      int isdir);
+
 /**
  * Initialise file operations on a regular file
  */

include/linux/fuse.h

@@ -99,7 +99,8 @@ enum fuse_opcode {
 	FUSE_INIT          = 26,
 	FUSE_OPENDIR       = 27,
 	FUSE_READDIR       = 28,
-	FUSE_RELEASEDIR    = 29
+	FUSE_RELEASEDIR    = 29,
+	FUSE_FSYNCDIR      = 30
 };
 
 /* Conservative buffer size for the client */