Move partition scanning from userspace to module.

Currently, zpool online -e (dynamic vdev expansion) doesn't work on
whole disks because we're invoking ioctl(BLKRRPART) from userspace
while ZFS still has a partition open on the disk, which results in
EBUSY.

This patch moves the BLKRRPART invocation from the zpool utility to the
module. Specifically, this is done just before opening the device in
vdev_disk_open() which is called inside vdev_reopen(). This requires
jumping through some hoops to get to the disk device from the partition
device, and to make sure we can still open the partition after the
BLKRRPART call.

Note that this new code path is triggered on dynamic vdev expansion
only; other actions, like creating a new pool, are unchanged and still
call BLKRRPART from userspace.

This change also depends on API changes which are available in 2.6.37
and latter kernels.  The build system has been updated to detect this,
but there is no compatibility mode for older kernels.  This means that
online expansion will NOT be available in older kernels.  However, it
will still be possible to expand the vdev offline.

Signed-off-by: Brian Behlendorf <[email protected]>
Closes #808

5 files changed, 9 insertions, 0 deletions

diff --git a/include/sys/Makefile.in b/include/sys/Makefile.in
index b949360cd..6e2229c55 100644
--- a/include/sys/Makefile.in
+++ b/include/sys/Makefile.in
@@ -64,6 +64,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-blk-rq-pos.m4 \
 	$(top_srcdir)/config/kernel-blk-rq-sectors.m4 \
 	$(top_srcdir)/config/kernel-blkdev-get-by-path.m4 \
+	$(top_srcdir)/config/kernel-blkdev-get.m4 \
 	$(top_srcdir)/config/kernel-check-disk-size-change.m4 \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
@@ -73,6 +74,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-fmode-t.m4 \
 	$(top_srcdir)/config/kernel-fsync.m4 \
 	$(top_srcdir)/config/kernel-get-disk-ro.m4 \
+	$(top_srcdir)/config/kernel-get-gendisk.m4 \
 	$(top_srcdir)/config/kernel-insert-inode-locked.m4 \
 	$(top_srcdir)/config/kernel-invalidate-bdev-args.m4 \
 	$(top_srcdir)/config/kernel-kobj-name-len.m4 \
diff --git a/include/sys/efi_partition.h b/include/sys/efi_partition.h
index e75e45a6b..ee367a574 100644
--- a/include/sys/efi_partition.h
+++ b/include/sys/efi_partition.h
@@ -229,6 +229,7 @@ struct partition64 {
 extern	int	efi_alloc_and_init(int, uint32_t, struct dk_gpt **);
 extern	int	efi_alloc_and_read(int, struct dk_gpt **);
 extern	int	efi_write(int, struct dk_gpt *);
+extern	int	efi_rescan(int);
 extern	void	efi_free(struct dk_gpt *);
 extern	int	efi_type(int);
 extern	void	efi_err_check(struct dk_gpt *);
diff --git a/include/sys/fm/Makefile.in b/include/sys/fm/Makefile.in
index 0ad4f3e35..c5383e8b9 100644
--- a/include/sys/fm/Makefile.in
+++ b/include/sys/fm/Makefile.in
@@ -64,6 +64,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-blk-rq-pos.m4 \
 	$(top_srcdir)/config/kernel-blk-rq-sectors.m4 \
 	$(top_srcdir)/config/kernel-blkdev-get-by-path.m4 \
+	$(top_srcdir)/config/kernel-blkdev-get.m4 \
 	$(top_srcdir)/config/kernel-check-disk-size-change.m4 \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
@@ -73,6 +74,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-fmode-t.m4 \
 	$(top_srcdir)/config/kernel-fsync.m4 \
 	$(top_srcdir)/config/kernel-get-disk-ro.m4 \
+	$(top_srcdir)/config/kernel-get-gendisk.m4 \
 	$(top_srcdir)/config/kernel-insert-inode-locked.m4 \
 	$(top_srcdir)/config/kernel-invalidate-bdev-args.m4 \
 	$(top_srcdir)/config/kernel-kobj-name-len.m4 \
diff --git a/include/sys/fm/fs/Makefile.in b/include/sys/fm/fs/Makefile.in
index acecb67d0..a121817da 100644
--- a/include/sys/fm/fs/Makefile.in
+++ b/include/sys/fm/fs/Makefile.in
@@ -64,6 +64,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-blk-rq-pos.m4 \
 	$(top_srcdir)/config/kernel-blk-rq-sectors.m4 \
 	$(top_srcdir)/config/kernel-blkdev-get-by-path.m4 \
+	$(top_srcdir)/config/kernel-blkdev-get.m4 \
 	$(top_srcdir)/config/kernel-check-disk-size-change.m4 \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
@@ -73,6 +74,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-fmode-t.m4 \
 	$(top_srcdir)/config/kernel-fsync.m4 \
 	$(top_srcdir)/config/kernel-get-disk-ro.m4 \
+	$(top_srcdir)/config/kernel-get-gendisk.m4 \
 	$(top_srcdir)/config/kernel-insert-inode-locked.m4 \
 	$(top_srcdir)/config/kernel-invalidate-bdev-args.m4 \
 	$(top_srcdir)/config/kernel-kobj-name-len.m4 \
diff --git a/include/sys/fs/Makefile.in b/include/sys/fs/Makefile.in
index 9f3ad2bc8..8ef1491eb 100644
--- a/include/sys/fs/Makefile.in
+++ b/include/sys/fs/Makefile.in
@@ -64,6 +64,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-blk-rq-pos.m4 \
 	$(top_srcdir)/config/kernel-blk-rq-sectors.m4 \
 	$(top_srcdir)/config/kernel-blkdev-get-by-path.m4 \
+	$(top_srcdir)/config/kernel-blkdev-get.m4 \
 	$(top_srcdir)/config/kernel-check-disk-size-change.m4 \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
@@ -73,6 +74,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-fmode-t.m4 \
 	$(top_srcdir)/config/kernel-fsync.m4 \
 	$(top_srcdir)/config/kernel-get-disk-ro.m4 \
+	$(top_srcdir)/config/kernel-get-gendisk.m4 \
 	$(top_srcdir)/config/kernel-insert-inode-locked.m4 \
 	$(top_srcdir)/config/kernel-invalidate-bdev-args.m4 \
 	$(top_srcdir)/config/kernel-kobj-name-len.m4 \