[PATCH 2/3] md: factor sb write alignment check into function

From: Christopher Unkel
Date: Thu Oct 22 2020 - 23:31:59 EST


Refactor in preparation for a second use of the logic.

Signed-off-by: Christopher Unkel <cunkel@xxxxxxxxxxxxxx>
---
drivers/md/md-bitmap.c | 72 +++++++++++++++++++++++-------------------
1 file changed, 40 insertions(+), 32 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 200c5d0f08bf..600b89d5a3ad 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -209,6 +209,44 @@ static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mdde
return NULL;
}

+static int sb_write_alignment_ok(struct mddev *mddev, struct md_rdev *rdev,
+ struct page *page, int offset, int size)
+{
+ if (mddev->external) {
+ /* Bitmap could be anywhere. */
+ if (rdev->sb_start + offset + (page->index
+ * (PAGE_SIZE/512))
+ > rdev->data_offset
+ &&
+ rdev->sb_start + offset
+ < (rdev->data_offset + mddev->dev_sectors
+ + (PAGE_SIZE/512)))
+ return 0;
+ } else if (offset < 0) {
+ /* DATA BITMAP METADATA */
+ if (offset
+ + (long)(page->index * (PAGE_SIZE/512))
+ + size/512 > 0)
+ /* bitmap runs in to metadata */
+ return 0;
+ if (rdev->data_offset + mddev->dev_sectors
+ > rdev->sb_start + offset)
+ /* data runs in to bitmap */
+ return 0;
+ } else if (rdev->sb_start < rdev->data_offset) {
+ /* METADATA BITMAP DATA */
+ if (rdev->sb_start
+ + offset
+ + page->index*(PAGE_SIZE/512) + size/512
+ > rdev->data_offset)
+ /* bitmap runs in to data */
+ return 0;
+ } else {
+ /* DATA METADATA BITMAP - no problems */
+ }
+ return 1;
+}
+
static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
{
struct md_rdev *rdev;
@@ -234,38 +272,8 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
/* Just make sure we aren't corrupting data or
* metadata
*/
- if (mddev->external) {
- /* Bitmap could be anywhere. */
- if (rdev->sb_start + offset + (page->index
- * (PAGE_SIZE/512))
- > rdev->data_offset
- &&
- rdev->sb_start + offset
- < (rdev->data_offset + mddev->dev_sectors
- + (PAGE_SIZE/512)))
- goto bad_alignment;
- } else if (offset < 0) {
- /* DATA BITMAP METADATA */
- if (offset
- + (long)(page->index * (PAGE_SIZE/512))
- + size/512 > 0)
- /* bitmap runs in to metadata */
- goto bad_alignment;
- if (rdev->data_offset + mddev->dev_sectors
- > rdev->sb_start + offset)
- /* data runs in to bitmap */
- goto bad_alignment;
- } else if (rdev->sb_start < rdev->data_offset) {
- /* METADATA BITMAP DATA */
- if (rdev->sb_start
- + offset
- + page->index*(PAGE_SIZE/512) + size/512
- > rdev->data_offset)
- /* bitmap runs in to data */
- goto bad_alignment;
- } else {
- /* DATA METADATA BITMAP - no problems */
- }
+ if (!sb_write_alignment_ok(mddev, rdev, page, offset, size))
+ goto bad_alignment;
md_super_write(mddev, rdev,
rdev->sb_start + offset
+ page->index * (PAGE_SIZE/512),
--
2.17.1