fuse: break up fuse_open_common()

fuse_open_common() has a lot of code relevant only for regular files and
O_TRUNC in particular.

Copy the little bit of remaining code into fuse_dir_open() and stop using
this common helper for directory open.

Also split out fuse_dir_finish_open() from fuse_finish_open() before we add
inode io modes to fuse_finish_open().
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dir.c

@@ -1630,7 +1630,30 @@ static const char *fuse_get_link(struct dentry *dentry, struct inode *inode,
 
 static int fuse_dir_open(struct inode *inode, struct file *file)
 {
-	return fuse_open_common(inode, file, true);
+	struct fuse_mount *fm = get_fuse_mount(inode);
+	int err;
+
+	if (fuse_is_bad(inode))
+		return -EIO;
+
+	err = generic_file_open(inode, file);
+	if (err)
+		return err;
+
+	err = fuse_do_open(fm, get_node_id(inode), file, true);
+	if (!err) {
+		struct fuse_file *ff = file->private_data;
+
+		/*
+		 * Keep handling FOPEN_STREAM and FOPEN_NONSEEKABLE for
+		 * directories for backward compatibility, though it's unlikely
+		 * to be useful.
+		 */
+		if (ff->open_flags & (FOPEN_STREAM | FOPEN_NONSEEKABLE))
+			nonseekable_open(inode, file);
+	}
+
+	return err;
 }
 
 static int fuse_dir_release(struct inode *inode, struct file *file)

fs/fuse/file.c

@@ -227,7 +227,7 @@ static void fuse_truncate_update_attr(struct inode *inode, struct file *file)
 	fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
 }
 
-int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
+static int fuse_open(struct inode *inode, struct file *file)
 {
 	struct fuse_mount *fm = get_fuse_mount(inode);
 	struct fuse_conn *fc = fm->fc;
@@ -256,7 +256,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 	if (is_wb_truncate || dax_truncate)
 		fuse_set_nowrite(inode);
 
-	err = fuse_do_open(fm, get_node_id(inode), file, isdir);
+	err = fuse_do_open(fm, get_node_id(inode), file, false);
 	if (!err) {
 		fuse_finish_open(inode, file);
 		if (is_truncate)
@@ -354,11 +354,6 @@ void fuse_release_common(struct file *file, bool isdir)
 			  (fl_owner_t) file, isdir);
 }
 
-static int fuse_open(struct inode *inode, struct file *file)
-{
-	return fuse_open_common(inode, file, false);
-}
-
 static int fuse_release(struct inode *inode, struct file *file)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);

fs/fuse/fuse_i.h

@@ -1031,11 +1031,6 @@ void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
 			 size_t count, int opcode);
 
 
-/**
- * Send OPEN or OPENDIR request
- */
-int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
-
 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release);
 void fuse_file_free(struct fuse_file *ff);
 void fuse_finish_open(struct inode *inode, struct file *file);