Merge pull request #888 from yangyun50/master

passthrough examples: enable direct io when open has flag: O_DIRECT

1 files changed, 15 insertions, 2 deletions

diff --git a/example/passthrough_fh.c b/example/passthrough_fh.c
index 51df3be..701d59e 100644
--- a/example/passthrough_fh.c
+++ b/example/passthrough_fh.c
@@ -54,6 +54,13 @@ static void *xmp_init(struct fuse_conn_info *conn,
 	cfg->use_ino = 1;
 	cfg->nullpath_ok = 1;
 
+	/* parallel_direct_writes feature depends on direct_io features.
+	   To make parallel_direct_writes valid, need either set cfg->direct_io
+	   in current function (recommended in high level API) or set fi->direct_io
+	   in xmp_create() or xmp_open(). */
+	// cfg->direct_io = 1;
+	cfg->parallel_direct_writes = 1;
+
 	/* Pick up changes from lower filesystem right away. This is
 	   also necessary for better hardlink support. When the kernel
 	   calls the unlink() handler, it does not know the inode of
@@ -366,7 +373,6 @@ static int xmp_create(const char *path, mode_t mode, struct fuse_file_info *fi)
 		return -errno;
 
 	fi->fh = fd;
-	fi->parallel_direct_writes = 1;
 	return 0;
 }
 
@@ -378,8 +384,15 @@ static int xmp_open(const char *path, struct fuse_file_info *fi)
 	if (fd == -1)
 		return -errno;
 
+        /* Enable direct_io when open has flags O_DIRECT to enjoy the feature
+           parallel_direct_writes (i.e., to get a shared lock, not exclusive lock,
+           for writes to the same file). */
+        if (fi->flags & O_DIRECT) {
+		fi->direct_io = 1;
+		fi->parallel_direct_writes = 1;
+	}
+
 	fi->fh = fd;
-	fi->parallel_direct_writes = 1;
 	return 0;
 }