bcache in userspace; userspace fsck

1 files changed, 155 insertions, 0 deletions

diff --git a/linux/blkdev.c b/linux/blkdev.c
new file mode 100644
index 0000000..b4ff451
--- /dev/null
+++ b/linux/blkdev.c
@@ -0,0 +1,155 @@
+
+#include <alloca.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/fs.h>
+
+int submit_bio_wait(struct bio *bio)
+{
+	struct iovec *iov;
+	struct bvec_iter iter;
+	struct bio_vec bv;
+	ssize_t ret;
+	unsigned i;
+
+	if (bio->bi_opf & REQ_PREFLUSH)
+		fdatasync(bio->bi_bdev->bd_fd);
+
+	i = 0;
+	bio_for_each_segment(bv, bio, iter)
+		i++;
+
+	iov = alloca(sizeof(*iov) * i);
+
+	i = 0;
+	bio_for_each_segment(bv, bio, iter)
+		iov[i++] = (struct iovec) {
+			.iov_base = page_address(bv.bv_page) + bv.bv_offset,
+			.iov_len = bv.bv_len,
+		};
+
+	switch (bio_op(bio)) {
+	case REQ_OP_READ:
+		ret = preadv(bio->bi_bdev->bd_fd, iov, i,
+			     bio->bi_iter.bi_sector << 9);
+		break;
+	case REQ_OP_WRITE:
+		ret = pwritev(bio->bi_bdev->bd_fd, iov, i,
+			      bio->bi_iter.bi_sector << 9);
+		break;
+	default:
+		BUG();
+	}
+
+	if (bio->bi_opf & REQ_FUA)
+		fdatasync(bio->bi_bdev->bd_fd);
+
+	return ret == bio->bi_iter.bi_size ? 0 : -EIO;
+}
+
+void generic_make_request(struct bio *bio)
+{
+	bio->bi_error = submit_bio_wait(bio);
+	bio_endio(bio);
+}
+
+int blkdev_issue_discard(struct block_device *bdev,
+			 sector_t sector, sector_t nr_sects,
+			 gfp_t gfp_mask, unsigned long flags)
+{
+	return 0;
+}
+
+unsigned bdev_logical_block_size(struct block_device *bdev)
+{
+	struct stat statbuf;
+	unsigned blksize;
+	int ret;
+
+	ret = fstat(bdev->bd_fd, &statbuf);
+	BUG_ON(ret);
+
+	if (!S_ISBLK(statbuf.st_mode))
+		return statbuf.st_blksize >> 9;
+
+	ret = ioctl(bdev->bd_fd, BLKPBSZGET, &blksize);
+	BUG_ON(ret);
+
+	return blksize >> 9;
+}
+
+sector_t get_capacity(struct gendisk *disk)
+{
+	struct block_device *bdev =
+		container_of(disk, struct block_device, __bd_disk);
+	struct stat statbuf;
+	u64 bytes;
+	int ret;
+
+	ret = fstat(bdev->bd_fd, &statbuf);
+	BUG_ON(ret);
+
+	if (!S_ISBLK(statbuf.st_mode))
+		return statbuf.st_size >> 9;
+
+	ret = ioctl(bdev->bd_fd, BLKGETSIZE64, &bytes);
+	BUG_ON(ret);
+
+	return bytes >> 9;
+}
+
+void blkdev_put(struct block_device *bdev, fmode_t mode)
+{
+	fdatasync(bdev->bd_fd);
+	close(bdev->bd_fd);
+	free(bdev);
+}
+
+struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
+					void *holder)
+{
+	struct block_device *bdev;
+	int flags = O_DIRECT;
+
+	if ((mode & (FMODE_READ|FMODE_WRITE)) == (FMODE_READ|FMODE_WRITE))
+		flags = O_RDWR;
+	else if (mode & FMODE_READ)
+		flags = O_RDONLY;
+	else if (mode & FMODE_WRITE)
+		flags = O_WRONLY;
+
+	if (mode & FMODE_EXCL)
+		flags |= O_EXCL;
+
+	bdev = malloc(sizeof(*bdev));
+	memset(bdev, 0, sizeof(*bdev));
+
+	strncpy(bdev->name, path, sizeof(bdev->name));
+	bdev->name[sizeof(bdev->name) - 1] = '\0';
+
+	bdev->bd_fd = open(path, flags);
+	bdev->bd_holder = holder;
+	bdev->bd_disk = &bdev->__bd_disk;
+
+	BUG_ON(bdev->bd_fd < 0);
+
+	return bdev;
+}
+
+void bdput(struct block_device *bdev)
+{
+	BUG();
+}
+
+struct block_device *lookup_bdev(const char *path)
+{
+	return ERR_PTR(-EINVAL);
+}