btrfs: zoned: fix full zone super block reading on ZNS

When both of the superblock zones are full, we need to check which
superblock is newer. The calculation of last superblock position is wrong
as it does not consider zone_capacity and uses the length.

Fixes: 9658b72ef300 ("btrfs: zoned: locate superblock position using zone capacity")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index d51057608fc3405b477d46aaca4f6d2962171b23..4243b0427a305c5590dd1482f8e7c464da99be36 100644 (file)
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -122,10 +122,9 @@ static int sb_write_pointer(struct block_device *bdev, struct blk_zone *zones,
                int i;
 
                for (i = 0; i < BTRFS_NR_SB_LOG_ZONES; i++) {
-                       u64 bytenr;
-
-                       bytenr = ((zones[i].start + zones[i].len)
-                                  << SECTOR_SHIFT) - BTRFS_SUPER_INFO_SIZE;
+                       u64 zone_end = (zones[i].start + zones[i].capacity) << SECTOR_SHIFT;
+                       u64 bytenr = ALIGN_DOWN(zone_end, BTRFS_SUPER_INFO_SIZE) -
+                                               BTRFS_SUPER_INFO_SIZE;
 
                        page[i] = read_cache_page_gfp(mapping,
                                        bytenr >> PAGE_SHIFT, GFP_NOFS);