linux shim: implement BLK_OPEN_CREAT

this allows O_CREAT to be passed through, for the new image creation
tool.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

6 files changed, 10 insertions, 6 deletions

diff --git a/c_src/cmd_device.c b/c_src/cmd_device.c
index 40ac87c7..96c25310 100644
--- a/c_src/cmd_device.c
+++ b/c_src/cmd_device.c
@@ -104,7 +104,7 @@ static int cmd_device_add(int argc, char *argv[])
 
 	struct bchfs_handle fs = bcache_fs_open(fs_path);
 
-	int ret = open_for_format(&dev_opts, force);
+	int ret = open_for_format(&dev_opts, 0, force);
 	if (ret)
 		die("Error opening %s: %s", dev_opts.path, strerror(-ret));
 
diff --git a/c_src/cmd_format.c b/c_src/cmd_format.c
index 6534469f..ac48454f 100644
--- a/c_src/cmd_format.c
+++ b/c_src/cmd_format.c
@@ -275,7 +275,7 @@ int cmd_format(int argc, char *argv[])
 	}
 
 	darray_for_each(devices, dev) {
-		int ret = open_for_format(dev, force);
+		int ret = open_for_format(dev, 0, force);
 		if (ret)
 			die("Error opening %s: %s", dev->path, strerror(-ret));
 	}
diff --git a/c_src/tools-util.c b/c_src/tools-util.c
index 496c875c..ea12946c 100644
--- a/c_src/tools-util.c
+++ b/c_src/tools-util.c
@@ -183,7 +183,7 @@ unsigned get_blocksize(int fd)
 }
 
 /* Open a block device, do magic blkid stuff to probe for existing filesystems: */
-int open_for_format(struct dev_opts *dev, bool force)
+int open_for_format(struct dev_opts *dev, blk_mode_t mode, bool force)
 {
 	int blkid_version_code = blkid_get_library_version(NULL, NULL);
 	if (blkid_version_code < 2401) {
@@ -208,7 +208,7 @@ int open_for_format(struct dev_opts *dev, bool force)
 	size_t fs_type_len, fs_label_len;
 
 	dev->file = bdev_file_open_by_path(dev->path,
-				BLK_OPEN_READ|BLK_OPEN_WRITE|BLK_OPEN_EXCL|BLK_OPEN_BUFFERED,
+				BLK_OPEN_READ|BLK_OPEN_WRITE|BLK_OPEN_EXCL|BLK_OPEN_BUFFERED|mode,
 				dev, NULL);
 	int ret = PTR_ERR_OR_ZERO(dev->file);
 	if (ret < 0)
diff --git a/c_src/tools-util.h b/c_src/tools-util.h
index d3d6b14b..27652b62 100644
--- a/c_src/tools-util.h
+++ b/c_src/tools-util.h
@@ -98,7 +98,7 @@ ssize_t read_string_list_or_die(const char *, const char * const[],
 u64 get_size(int);
 unsigned get_blocksize(int);
 struct dev_opts;
-int open_for_format(struct dev_opts *, bool);
+int open_for_format(struct dev_opts *, blk_mode_t, bool);
 
 bool ask_yn(void);
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index e3c3a9b4..ee27b615 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -33,6 +33,7 @@ typedef unsigned int __bitwise blk_mode_t;
 #define BLK_OPEN_WRITE_IOCTL	((__force blk_mode_t)(1 << 4))
 
 #define BLK_OPEN_BUFFERED	((__force blk_mode_t)(1 << 5))
+#define BLK_OPEN_CREAT		((__force blk_mode_t)(1 << 6))
 
 struct inode {
 	unsigned long		i_ino;
diff --git a/linux/blkdev.c b/linux/blkdev.c
index d073ed6a..3569594f 100644
--- a/linux/blkdev.c
+++ b/linux/blkdev.c
@@ -190,7 +190,10 @@ struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
 	if (mode & BLK_OPEN_EXCL)
 		flags |= O_EXCL;
 
-	fd = open(path, flags);
+	if (mode & BLK_OPEN_CREAT)
+		flags |= O_CREAT;
+
+	fd = open(path, flags, 0600);
 	if (fd < 0)
 		return ERR_PTR(-errno);