dm raid: fix panic when attempting to force a raid to sync

[ Upstream commit 233978449074ca7e45d9c959f9ec612d1b852893 ]

Requesting a sync on an active raid device via a table reload
(see 'sync' parameter in Documentation/device-mapper/dm-raid.txt)
skips the super_load() call that defines the superblock size
(rdev->sb_size) -- resulting in an oops if/when super_sync()->memset()
is called.

Fix by moving the initialization of the superblock start and size
out of super_load() to the caller (analyse_superblocks).

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 2245d06..a25eebd 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2143,13 +2143,6 @@ static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
        struct dm_raid_superblock *refsb;
        uint64_t events_sb, events_refsb;
 
-       rdev->sb_start = 0;
-       rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
-       if (rdev->sb_size < sizeof(*sb) || rdev->sb_size > PAGE_SIZE) {
-               DMERR("superblock size of a logical block is no longer valid");
-               return -EINVAL;
-       }
-
        r = read_disk_sb(rdev, rdev->sb_size, false);
        if (r)
                return r;
@@ -2494,6 +2487,17 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
                if (test_bit(Journal, &rdev->flags))
                        continue;
 
+               if (!rdev->meta_bdev)
+                       continue;
+
+               /* Set superblock offset/size for metadata device. */
+               rdev->sb_start = 0;
+               rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
+               if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
+                       DMERR("superblock size of a logical block is no longer valid");
+                       return -EINVAL;
+               }
+
                /*
                 * Skipping super_load due to CTR_FLAG_SYNC will cause
                 * the array to undergo initialization again as
@@ -2506,9 +2510,6 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
                if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
                        continue;
 
-               if (!rdev->meta_bdev)
-                       continue;
-
                r = super_load(rdev, freshest);
 
                switch (r) {