Merge tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...

[linux-block.git] / fs / btrfs / raid56.c

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 8ec34ecb6d687583030884bb27e74c4ceef3a399..83334df6f493c82857122f1ac0b89f6a0789436e 100644 (file)
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -2359,16 +2359,21 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
        SetPageUptodate(p_page);
 
        if (has_qstripe) {
+               /* RAID6, allocate and map temp space for the Q stripe */
                q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
                if (!q_page) {
                        __free_page(p_page);
                        goto cleanup;
                }
                SetPageUptodate(q_page);
+               pointers[rbio->real_stripes - 1] = kmap(q_page);
        }
 
        atomic_set(&rbio->error, 0);
 
+       /* Map the parity stripe just once */
+       pointers[nr_data] = kmap(p_page);
+
        for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
                struct page *p;
                void *parity;
@@ -2378,16 +2383,8 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
                        pointers[stripe] = kmap(p);
                }
 
-               /* then add the parity stripe */
-               pointers[stripe++] = kmap(p_page);
-
                if (has_qstripe) {
-                       /*
-                        * raid6, add the qstripe and call the
-                        * library function to fill in our p/q
-                        */
-                       pointers[stripe++] = kmap(q_page);
-
+                       /* RAID6, call the library function to fill in our P/Q */
                        raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
                                                pointers);
                } else {
@@ -2408,12 +2405,14 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 
                for (stripe = 0; stripe < nr_data; stripe++)
                        kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
-               kunmap(p_page);
        }
 
+       kunmap(p_page);
        __free_page(p_page);
-       if (q_page)
+       if (q_page) {
+               kunmap(q_page);
                __free_page(q_page);
+       }
 
 writeback:
        /*