md/raid5-cache: fix crc in rewrite_data_only_stripes()

r5l_recovery_create_empty_meta_block() creates crc for the empty
metablock. After the metablock is updated, we need clear the
checksum before recalculate it.

Shaohua: moved checksum calculation out of
r5l_recovery_create_empty_meta_block. We should calculate it after all fields
are updated.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 7c732c5f87c9..aa990bde1fe2 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -1522,7 +1522,6 @@ r5l_recovery_create_empty_meta_block(struct r5l_log *log,
                                      sector_t pos, u64 seq)
 {
         struct r5l_meta_block *mb;
-        u32 crc;
 
         mb = page_address(page);
         clear_page(mb);
@@ -1531,19 +1530,21 @@ r5l_recovery_create_empty_meta_block(struct r5l_log *log,
         mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
         mb->seq = cpu_to_le64(seq);
         mb->position = cpu_to_le64(pos);
-        crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
-        mb->checksum = cpu_to_le32(crc);
 }
 
 static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
                                           u64 seq)
 {
         struct page *page;
+        struct r5l_meta_block *mb;
 
         page = alloc_page(GFP_KERNEL);
         if (!page)
                 return -ENOMEM;
         r5l_recovery_create_empty_meta_block(log, page, pos, seq);
+        mb = page_address(page);
+        mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
+                                             mb, PAGE_SIZE));
         if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, REQ_OP_WRITE,
                           WRITE_FUA, false)) {
                 __free_page(page);
@@ -2117,7 +2118,8 @@ r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
                         }
                 }
                 mb->meta_size = cpu_to_le32(offset);
-                mb->checksum = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
+                mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
+                                                     mb, PAGE_SIZE));
                 sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page,
                              REQ_OP_WRITE, WRITE_FUA, false);
                 sh->log_start = ctx->pos;