Linux 4.13 compat: bio->bi_status and blk_status_t

Commit torvalds/linux@4e4cbee9.  The bio->bi_error field was
replaced with bio->bi_status which is an enum that describes
all possible error types.

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6351

config/kernel-bio-end-io-t-args.m4

@@ -22,3 +22,25 @@ AC_DEFUN([ZFS_AC_KERNEL_BIO_END_IO_T_ARGS], [
 		AC_MSG_RESULT(no)
 	])
 ])
+
+dnl #
+dnl # 4.13 API change
+dnl # The bio->bi_error field was replaced with bio->bi_status which is an
+dnl # enum which describes all possible error types.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_BIO_BI_STATUS], [
+	AC_MSG_CHECKING([whether bio->bi_status exists])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/bio.h>
+	],[
+		struct bio bio __attribute__ ((unused));
+		blk_status_t status __attribute__ ((unused)) = BLK_STS_OK;
+
+		bio.bi_status = status;
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_BIO_BI_STATUS, 1, [bio->bi_status exists])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])

config/kernel.m4

@@ -30,6 +30,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_REQ_OP_FLUSH
 	ZFS_AC_KERNEL_BIO_BI_OPF
 	ZFS_AC_KERNEL_BIO_END_IO_T_ARGS
+	ZFS_AC_KERNEL_BIO_BI_STATUS
 	ZFS_AC_KERNEL_BIO_RW_BARRIER
 	ZFS_AC_KERNEL_BIO_RW_DISCARD
 	ZFS_AC_KERNEL_BLK_QUEUE_BDI

include/linux/blkdev_compat.h

@@ -221,14 +221,104 @@ bio_set_flags_failfast(struct block_device *bdev, int *flags)
 #define	DISK_NAME_LEN	32
 #endif /* DISK_NAME_LEN */
 
+#ifdef HAVE_BIO_BI_STATUS
+static inline int
+bi_status_to_errno(blk_status_t status)
+{
+	switch (status)	{
+	case BLK_STS_OK:
+		return (0);
+	case BLK_STS_NOTSUPP:
+		return (EOPNOTSUPP);
+	case BLK_STS_TIMEOUT:
+		return (ETIMEDOUT);
+	case BLK_STS_NOSPC:
+		return (ENOSPC);
+	case BLK_STS_TRANSPORT:
+		return (ENOLINK);
+	case BLK_STS_TARGET:
+		return (EREMOTEIO);
+	case BLK_STS_NEXUS:
+		return (EBADE);
+	case BLK_STS_MEDIUM:
+		return (ENODATA);
+	case BLK_STS_PROTECTION:
+		return (EILSEQ);
+	case BLK_STS_RESOURCE:
+		return (ENOMEM);
+	case BLK_STS_AGAIN:
+		return (EAGAIN);
+	case BLK_STS_IOERR:
+		return (EIO);
+	default:
+		return (EIO);
+	}
+}
+
+static inline blk_status_t
+errno_to_bi_status(int error)
+{
+	switch (error) {
+	case 0:
+		return (BLK_STS_OK);
+	case EOPNOTSUPP:
+		return (BLK_STS_NOTSUPP);
+	case ETIMEDOUT:
+		return (BLK_STS_TIMEOUT);
+	case ENOSPC:
+		return (BLK_STS_NOSPC);
+	case ENOLINK:
+		return (BLK_STS_TRANSPORT);
+	case EREMOTEIO:
+		return (BLK_STS_TARGET);
+	case EBADE:
+		return (BLK_STS_NEXUS);
+	case ENODATA:
+		return (BLK_STS_MEDIUM);
+	case EILSEQ:
+		return (BLK_STS_PROTECTION);
+	case ENOMEM:
+		return (BLK_STS_RESOURCE);
+	case EAGAIN:
+		return (BLK_STS_AGAIN);
+	case EIO:
+		return (BLK_STS_IOERR);
+	default:
+		return (BLK_STS_IOERR);
+	}
+}
+#endif /* HAVE_BIO_BI_STATUS */
+
 /*
  * 4.3 API change
  * The bio_endio() prototype changed slightly.  These are helper
  * macro's to ensure the prototype and invocation are handled.
  */
 #ifdef HAVE_1ARG_BIO_END_IO_T
+#ifdef HAVE_BIO_BI_STATUS
+#define	BIO_END_IO_ERROR(bio)		bi_status_to_errno(bio->bi_status)
 #define	BIO_END_IO_PROTO(fn, x, z)	static void fn(struct bio *x)
-#define	BIO_END_IO(bio, error)		bio->bi_error = error; bio_endio(bio);
+#define	BIO_END_IO(bio, error)		bio_set_bi_status(bio, error)
+static inline void
+bio_set_bi_status(struct bio *bio, int error)
+{
+	ASSERT3S(error, <=, 0);
+	bio->bi_status = errno_to_bi_status(-error);
+	bio_endio(bio);
+}
+#else
+#define	BIO_END_IO_ERROR(bio)		(-(bio->bi_error))
+#define	BIO_END_IO_PROTO(fn, x, z)	static void fn(struct bio *x)
+#define	BIO_END_IO(bio, error)		bio_set_bi_error(bio, error)
+static inline void
+bio_set_bi_error(struct bio *bio, int error)
+{
+	ASSERT3S(error, <=, 0);
+	bio->bi_error = error;
+	bio_endio(bio);
+}
+#endif /* HAVE_BIO_BI_STATUS */
+
 #else
 #define	BIO_END_IO_PROTO(fn, x, z)	static void fn(struct bio *x, int z)
 #define	BIO_END_IO(bio, error)		bio_endio(bio, error);

module/zfs/vdev_disk.c

@@ -427,7 +427,7 @@ BIO_END_IO_PROTO(vdev_disk_physio_completion, bio, error)
 
 	if (dr->dr_error == 0) {
 #ifdef HAVE_1ARG_BIO_END_IO_T
-		dr->dr_error = -(bio->bi_error);
+		dr->dr_error = BIO_END_IO_ERROR(bio);
 #else
 		if (error)
 			dr->dr_error = -(error);
@@ -618,15 +618,16 @@ retry:
 	return (error);
 }
 
-BIO_END_IO_PROTO(vdev_disk_io_flush_completion, bio, rc)
+BIO_END_IO_PROTO(vdev_disk_io_flush_completion, bio, error)
 {
 	zio_t *zio = bio->bi_private;
 #ifdef HAVE_1ARG_BIO_END_IO_T
-	int rc = bio->bi_error;
+	zio->io_error = BIO_END_IO_ERROR(bio);
+#else
+	zio->io_error = -error;
 #endif
 
-	zio->io_error = -rc;
-	if (rc && (rc == -EOPNOTSUPP))
+	if (zio->io_error && (zio->io_error == EOPNOTSUPP))
 		zio->io_vd->vdev_nowritecache = B_TRUE;
 
 	bio_put(bio);