Merge branch 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-5.9/drivers

Pull MD fixes from Song.

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid5: Allow degraded raid6 to do rmw
  md/raid5: Fix Force reconstruct-write io stuck in degraded raid5
  raid5: don't duplicate code for different paths in handle_stripe
  raid5-cache: hold spinlock instead of mutex in r5c_journal_mode_show
  md: print errno in super_written
  md/raid5: remove the redundant setting of STRIPE_HANDLE
  md: register new md sysfs file 'uuid' read-only
  md: fix max sectors calculation for super 1.0

1 files changed, 42 insertions, 5 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index ea48bc25cce1..9c69084cae73 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -978,7 +978,8 @@ static void super_written(struct bio *bio)
 	struct mddev *mddev = rdev->mddev;
 
 	if (bio->bi_status) {
-		pr_err("md: super_written gets error=%d\n", bio->bi_status);
+		pr_err("md: %s gets error=%d\n", __func__,
+		       blk_status_to_errno(bio->bi_status));
 		md_error(mddev, rdev);
 		if (!test_bit(Faulty, &rdev->flags)
 		    && (bio->bi_opf & MD_FAILFAST)) {
@@ -2193,6 +2194,24 @@ retry:
 	sb->sb_csum = calc_sb_1_csum(sb);
 }
 
+static sector_t super_1_choose_bm_space(sector_t dev_size)
+{
+	sector_t bm_space;
+
+	/* if the device is bigger than 8Gig, save 64k for bitmap
+	 * usage, if bigger than 200Gig, save 128k
+	 */
+	if (dev_size < 64*2)
+		bm_space = 0;
+	else if (dev_size - 64*2 >= 200*1024*1024*2)
+		bm_space = 128*2;
+	else if (dev_size - 4*2 > 8*1024*1024*2)
+		bm_space = 64*2;
+	else
+		bm_space = 4*2;
+	return bm_space;
+}
+
 static unsigned long long
 super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
 {
@@ -2213,13 +2232,22 @@ super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
 		return 0;
 	} else {
 		/* minor version 0; superblock after data */
-		sector_t sb_start;
-		sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
+		sector_t sb_start, bm_space;
+		sector_t dev_size = i_size_read(rdev->bdev->bd_inode) >> 9;
+
+		/* 8K is for superblock */
+		sb_start = dev_size - 8*2;
 		sb_start &= ~(sector_t)(4*2 - 1);
-		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
+
+		bm_space = super_1_choose_bm_space(dev_size);
+
+		/* Space that can be used to store date needs to decrease
+		 * superblock bitmap space and bad block space(4K)
+		 */
+		max_sectors = sb_start - bm_space - 4*2;
+
 		if (!num_sectors || num_sectors > max_sectors)
 			num_sectors = max_sectors;
-		rdev->sb_start = sb_start;
 	}
 	sb = page_address(rdev->sb_page);
 	sb->data_size = cpu_to_le64(num_sectors);
@@ -4226,6 +4254,14 @@ static struct md_sysfs_entry md_raid_disks =
 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
 
 static ssize_t
+uuid_show(struct mddev *mddev, char *page)
+{
+	return sprintf(page, "%pU\n", mddev->uuid);
+}
+static struct md_sysfs_entry md_uuid =
+__ATTR(uuid, S_IRUGO, uuid_show, NULL);
+
+static ssize_t
 chunk_size_show(struct mddev *mddev, char *page)
 {
 	if (mddev->reshape_position != MaxSector &&
@@ -5481,6 +5517,7 @@ static struct attribute *md_default_attrs[] = {
 	&md_level.attr,
 	&md_layout.attr,
 	&md_raid_disks.attr,
+	&md_uuid.attr,
 	&md_chunk_size.attr,
 	&md_size.attr,
 	&md_resync_start.attr,