--- /dev/null
+
+#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 <libaio.h>
+
+#ifdef CONFIG_VALGRIND
+#include <valgrind/memcheck.h>
+#endif
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/completion.h>
+#include <linux/fs.h>
+#include <linux/kthread.h>
+
+#include "tools-util.h"
+
+struct fops {
+ void (*init)(void);
+ void (*cleanup)(void);
+ void (*read)(struct bio *bio, struct iovec * iov, unsigned i);
+ void (*write)(struct bio *bio, struct iovec * iov, unsigned i);
+};
+
+static struct fops *fops;
+static io_context_t aio_ctx;
+static atomic_t running_requests;
+
+void generic_make_request(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) {
+ ret = fdatasync(bio->bi_bdev->bd_fd);
+ if (ret) {
+ fprintf(stderr, "fsync error: %m\n");
+ bio->bi_status = BLK_STS_IOERR;
+ bio_endio(bio);
+ return;
+ }
+ }
+
+ i = 0;
+ bio_for_each_segment(bv, bio, iter)
+ i++;
+
+ iov = alloca(sizeof(*iov) * i);
+
+ i = 0;
+ bio_for_each_segment(bv, bio, iter) {
+ void *start = page_address(bv.bv_page) + bv.bv_offset;
+ size_t len = bv.bv_len;
+
+ iov[i++] = (struct iovec) {
+ .iov_base = start,
+ .iov_len = len,
+ };
+
+#ifdef CONFIG_VALGRIND
+ /* To be pedantic it should only be on IO completion. */
+ if (bio_op(bio) == REQ_OP_READ)
+ VALGRIND_MAKE_MEM_DEFINED(start, len);
+#endif
+ }
+
+ switch (bio_op(bio)) {
+ case REQ_OP_READ:
+ fops->read(bio, iov, i);
+ break;
+ case REQ_OP_WRITE:
+ fops->write(bio, iov, i);
+ break;
+ case REQ_OP_FLUSH:
+ ret = fsync(bio->bi_bdev->bd_fd);
+ if (ret)
+ die("fsync error: %m");
+ bio_endio(bio);
+ break;
+ default:
+ BUG();
+ }
+}
+
+static void submit_bio_wait_endio(struct bio *bio)
+{
+ complete(bio->bi_private);
+}
+
+int submit_bio_wait(struct bio *bio)
+{
+ struct completion done;
+
+ init_completion(&done);
+ bio->bi_private = &done;
+ bio->bi_end_io = submit_bio_wait_endio;
+ bio->bi_opf |= REQ_SYNC;
+ submit_bio(bio);
+ wait_for_completion(&done);
+
+ return blk_status_to_errno(bio->bi_status);
+}
+
+int blkdev_issue_discard(struct block_device *bdev,
+ sector_t sector, sector_t nr_sects,
+ gfp_t gfp_mask)
+{
+ return 0;
+}
+
+int blkdev_issue_zeroout(struct block_device *bdev,
+ sector_t sector, sector_t nr_sects,
+ gfp_t gfp_mask, unsigned flags)
+{
+ /* Not yet implemented: */
+ BUG();
+}
+
+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;
+
+ xioctl(bdev->bd_fd, BLKPBSZGET, &blksize);
+ return blksize;
+}
+
+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, void *holder)
+{
+ fdatasync(bdev->bd_fd);
+ close(bdev->bd_fd);
+ free(bdev);
+}
+
+struct block_device *blkdev_get_by_path(const char *path, blk_mode_t mode,
+ void *holder, const struct blk_holder_ops *hop)
+{
+ struct block_device *bdev;
+ int fd, flags = 0;
+
+ if ((mode & (BLK_OPEN_READ|BLK_OPEN_WRITE)) == (BLK_OPEN_READ|BLK_OPEN_WRITE))
+ flags = O_RDWR;
+ else if (mode & BLK_OPEN_READ)
+ flags = O_RDONLY;
+ else if (mode & BLK_OPEN_WRITE)
+ flags = O_WRONLY;
+
+ if (!(mode & BLK_OPEN_BUFFERED))
+ flags |= O_DIRECT;
+
+ if (mode & BLK_OPEN_EXCL)
+ flags |= O_EXCL;
+
+ fd = open(path, flags);
+ if (fd < 0)
+ return ERR_PTR(-errno);
+
+ 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_dev = xfstat(fd).st_rdev;
+ bdev->bd_fd = fd;
+ bdev->bd_holder = holder;
+ bdev->bd_disk = &bdev->__bd_disk;
+ bdev->bd_disk->bdi = &bdev->bd_disk->__bdi;
+ bdev->queue.backing_dev_info = bdev->bd_disk->bdi;
+
+ return bdev;
+}
+
+void bdput(struct block_device *bdev)
+{
+ BUG();
+}
+
+int lookup_bdev(const char *path, dev_t *dev)
+{
+ return -EINVAL;
+}
+
+static void io_fallback(void)
+{
+ fops++;
+ if (fops->init == NULL)
+ die("no fallback possible, something is very wrong");
+ fops->init();
+}
+
+static void sync_check(struct bio *bio, int ret)
+{
+ if (ret != bio->bi_iter.bi_size) {
+ die("IO error: %s\n", strerror(-ret));
+ }
+
+ if (bio->bi_opf & REQ_FUA) {
+ ret = fdatasync(bio->bi_bdev->bd_fd);
+ if (ret)
+ die("fsync error: %s\n", strerror(-ret));
+ }
+ bio_endio(bio);
+}
+
+static void sync_init(void) {}
+
+static void sync_cleanup(void)
+{
+ /* not necessary? */
+ sync();
+}
+
+static void sync_read(struct bio *bio, struct iovec * iov, unsigned i)
+{
+
+ ssize_t ret = preadv(bio->bi_bdev->bd_fd, iov, i,
+ bio->bi_iter.bi_sector << 9);
+ sync_check(bio, ret);
+}
+
+static void sync_write(struct bio *bio, struct iovec * iov, unsigned i)
+{
+ ssize_t ret = pwritev2(bio->bi_bdev->bd_fd, iov, i,
+ bio->bi_iter.bi_sector << 9,
+ bio->bi_opf & REQ_FUA ? RWF_SYNC : 0);
+ sync_check(bio, ret);
+}
+
+static DECLARE_WAIT_QUEUE_HEAD(aio_events_completed);
+
+static int aio_completion_thread(void *arg)
+{
+ struct io_event events[8], *ev;
+ int ret;
+ bool stop = false;
+
+ while (!stop) {
+ ret = io_getevents(aio_ctx, 1, ARRAY_SIZE(events),
+ events, NULL);
+
+ if (ret < 0 && ret == -EINTR)
+ continue;
+ if (ret < 0)
+ die("io_getevents() error: %s", strerror(-ret));
+ if (ret)
+ wake_up(&aio_events_completed);
+
+ for (ev = events; ev < events + ret; ev++) {
+ struct bio *bio = (struct bio *) ev->data;
+
+ /* This should only happen during blkdev_cleanup() */
+ if (!bio) {
+ BUG_ON(atomic_read(&running_requests) != 0);
+ stop = true;
+ continue;
+ }
+
+ if (ev->res != bio->bi_iter.bi_size)
+ bio->bi_status = BLK_STS_IOERR;
+
+ bio_endio(bio);
+ atomic_dec(&running_requests);
+ }
+ }
+
+ return 0;
+}
+
+static struct task_struct *aio_task = NULL;
+
+static void aio_init(void)
+{
+ struct task_struct *p;
+ long err = io_setup(256, &aio_ctx);
+ if (!err) {
+ p = kthread_run(aio_completion_thread, NULL, "aio_completion");
+ BUG_ON(IS_ERR(p));
+
+ aio_task = p;
+
+ } else if (err == -ENOSYS) {
+ io_fallback();
+ } else {
+ die("io_setup() error: %s", strerror(err));
+ }
+}
+
+static void aio_cleanup(void)
+{
+ struct task_struct *p = NULL;
+ swap(aio_task, p);
+ get_task_struct(p);
+
+ /* I mean, really?! IO_CMD_NOOP is even defined, but not implemented. */
+ int fds[2];
+ int ret = pipe(fds);
+ if (ret != 0)
+ die("pipe err: %s", strerror(ret));
+
+ /* Wake up the completion thread with spurious work. */
+ int junk = 0;
+ struct iocb iocb = {
+ .aio_lio_opcode = IO_CMD_PWRITE,
+ .data = NULL, /* Signal to stop */
+ .aio_fildes = fds[1],
+ .u.c.buf = &junk,
+ .u.c.nbytes = 1,
+ }, *iocbp = &iocb;
+ ret = io_submit(aio_ctx, 1, &iocbp);
+ if (ret != 1)
+ die("io_submit cleanup err: %s", strerror(-ret));
+
+ ret = kthread_stop(p);
+ BUG_ON(ret);
+
+ put_task_struct(p);
+
+ close(fds[0]);
+ close(fds[1]);
+}
+
+static void aio_op(struct bio *bio, struct iovec *iov, unsigned i, int opcode)
+{
+ ssize_t ret;
+ struct iocb iocb = {
+ .data = bio,
+ .aio_fildes = bio->bi_bdev->bd_fd,
+ .aio_rw_flags = bio->bi_opf & REQ_FUA ? RWF_SYNC : 0,
+ .aio_lio_opcode = opcode,
+ .u.c.buf = iov,
+ .u.c.nbytes = i,
+ .u.c.offset = bio->bi_iter.bi_sector << 9,
+
+ }, *iocbp = &iocb;
+
+ atomic_inc(&running_requests);
+
+ wait_event(aio_events_completed,
+ (ret = io_submit(aio_ctx, 1, &iocbp)) != -EAGAIN);;
+
+ if (ret != 1)
+ die("io_submit err: %s", strerror(-ret));
+}
+
+static void aio_read(struct bio *bio, struct iovec *iov, unsigned i)
+{
+ aio_op(bio, iov, i, IO_CMD_PREADV);
+}
+
+static void aio_write(struct bio *bio, struct iovec * iov, unsigned i)
+{
+ aio_op(bio, iov, i, IO_CMD_PWRITEV);
+}
+
+
+/* not implemented */
+static void uring_init(void) {
+ io_fallback();
+}
+
+struct fops fops_list[] = {
+ {
+ .init = uring_init,
+ }, {
+ .init = aio_init,
+ .cleanup = aio_cleanup,
+ .read = aio_read,
+ .write = aio_write,
+ }, {
+ .init = sync_init,
+ .cleanup = sync_cleanup,
+ .read = sync_read,
+ .write = sync_write,
+ }, {
+ /* NULL */
+ }
+};
+
+__attribute__((constructor(102)))
+static void blkdev_init(void)
+{
+ fops = fops_list;
+ fops->init();
+}
+
+__attribute__((destructor(102)))
+static void blkdev_cleanup(void)
+{
+ fops->cleanup();
+}
projects / bcachefs-tools-debian / blobdiff