drbd: fix NULL pointer dereference on 4k hard sect size
we still don't support 4k 'physical' sectors 'natively',
but use a read-modify-write workaround.
And we even tried to use the extra page before we allocated it :(
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 4df3b40..d53d36c 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -941,6 +941,25 @@
drbd_md_set_sector_offsets(mdev, nbc);
+ /* allocate a second IO page if logical_block_size != 512 */
+ logical_block_size = bdev_logical_block_size(nbc->md_bdev);
+ if (logical_block_size == 0)
+ logical_block_size = MD_SECTOR_SIZE;
+
+ if (logical_block_size != MD_SECTOR_SIZE) {
+ if (!mdev->md_io_tmpp) {
+ struct page *page = alloc_page(GFP_NOIO);
+ if (!page)
+ goto force_diskless_dec;
+
+ dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",
+ logical_block_size, MD_SECTOR_SIZE);
+ dev_warn(DEV, "Workaround engaged (has performance impact).\n");
+
+ mdev->md_io_tmpp = page;
+ }
+ }
+
if (!mdev->bitmap) {
if (drbd_bm_init(mdev)) {
retcode = ERR_NOMEM;
@@ -980,25 +999,6 @@
goto force_diskless_dec;
}
- /* allocate a second IO page if logical_block_size != 512 */
- logical_block_size = bdev_logical_block_size(nbc->md_bdev);
- if (logical_block_size == 0)
- logical_block_size = MD_SECTOR_SIZE;
-
- if (logical_block_size != MD_SECTOR_SIZE) {
- if (!mdev->md_io_tmpp) {
- struct page *page = alloc_page(GFP_NOIO);
- if (!page)
- goto force_diskless_dec;
-
- dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",
- logical_block_size, MD_SECTOR_SIZE);
- dev_warn(DEV, "Workaround engaged (has performance impact).\n");
-
- mdev->md_io_tmpp = page;
- }
- }
-
/* Reset the "barriers don't work" bits here, then force meta data to
* be written, to ensure we determine if barriers are supported. */
if (nbc->dc.no_md_flush)