From 426e517d3e2f2357707394fd442aedba11ae76c6 Mon Sep 17 00:00:00 2001
From: Radek Podgorny <radek@podgorny.cz>
Date: Sat, 27 Aug 2022 00:56:48 +0200
Subject: add support for direct-io

---
 src/fuse_ops.c | 11 ++++++++++-
 src/opts.c     |  4 ++++
 src/opts.h     |  4 +++-
 src/unionfs.c  |  1 +
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/fuse_ops.c b/src/fuse_ops.c
index 20d8cbb..bed5086 100644
--- a/src/fuse_ops.c
+++ b/src/fuse_ops.c
@@ -125,6 +125,10 @@ static int unionfs_create(const char *path, mode_t mode, struct fuse_file_info *
 	// NOW, that the file has the proper owner we may set the requested mode
 	fchmod(res, mode);
 
+	if (uopt.direct_io) {
+		fi->direct_io = 1;
+	}
+
 	fi->fh = res;
 	remove_hidden(path, i);
 
@@ -421,8 +425,13 @@ static int unionfs_open(const char *path, struct fuse_file_info *fi) {
 		remove_hidden(path, i);
 	}
 
-	// This makes exec() fail
+	// This makes exec() fail - wtf is this? obsolete?
 	//fi->direct_io = 1;
+
+	if (uopt.direct_io) {
+		fi->direct_io = 1;
+	}
+
 	fi->fh = (unsigned long)fd;
 
 	DBG("fd = %"PRIx64"\n", fi->fh);
diff --git a/src/opts.c b/src/opts.c
index 6b444f6..f8680b7 100644
--- a/src/opts.c
+++ b/src/opts.c
@@ -292,6 +292,7 @@ static void print_help(const char *progname) {
 	"    -o relaxed_permissions Disable permissions checks, but only if\n"
 	"                           running neither as UID=0 or GID=0\n"
 	"    -o statfs_omit_ro      do not count blocks of ro-branches\n"
+	"    -o direct_io           Enable direct-io flag for fuse subsystem\n"
 	"\n",
 	progname);
 }
@@ -394,6 +395,9 @@ int unionfs_opt_proc(void *data, const char *arg, int key, struct fuse_args *out
 		case KEY_RELAXED_PERMISSIONS:
 			uopt.relaxed_permissions = true;
 			return 0;
+		case KEY_DIRECT_IO:
+			uopt.direct_io = true;
+			return 0;
 		case KEY_VERSION:
 			printf("unionfs-fuse version: "VERSION"\n");
 #ifdef HAVE_XATTR
diff --git a/src/opts.h b/src/opts.h
index 0ee2d08..ab0814e 100644
--- a/src/opts.h
+++ b/src/opts.h
@@ -31,6 +31,7 @@ typedef struct {
 	pthread_rwlock_t dbgpath_lock; // locks dbgpath
 	bool hide_meta_files;
 	bool relaxed_permissions;
+	bool direct_io;
 
 } uopt_t;
 
@@ -47,7 +48,8 @@ enum {
 	KEY_NOINITGROUPS,
 	KEY_RELAXED_PERMISSIONS,
 	KEY_STATFS_OMIT_RO,
-	KEY_VERSION
+	KEY_DIRECT_IO,
+	KEY_VERSION,
 };
 
 
diff --git a/src/unionfs.c b/src/unionfs.c
index 361784f..6949ba1 100644
--- a/src/unionfs.c
+++ b/src/unionfs.c
@@ -35,6 +35,7 @@ static struct fuse_opt unionfs_opts[] = {
 	FUSE_OPT_KEY("noinitgroups", KEY_NOINITGROUPS),
 	FUSE_OPT_KEY("relaxed_permissions", KEY_RELAXED_PERMISSIONS),
 	FUSE_OPT_KEY("statfs_omit_ro", KEY_STATFS_OMIT_RO),
+	FUSE_OPT_KEY("direct_io", KEY_DIRECT_IO),
 	FUSE_OPT_KEY("--version", KEY_VERSION),
 	FUSE_OPT_KEY("-V", KEY_VERSION),
 	FUSE_OPT_END
-- 
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