btrfs-progs: docs: fix typos

[platform/upstream/btrfs-progs.git] / kernel-lib / raid56.c

diff --git a/kernel-lib/raid56.c b/kernel-lib/raid56.c
index dca8f8d..e3a9339 100644 (file)
--- a/kernel-lib/raid56.c
+++ b/kernel-lib/raid56.c
@@ -239,3 +239,121 @@ int raid6_recov_data2(int nr_devs, size_t stripe_len, int dest1, int dest2,
        free(zero_mem2);
        return ret;
 }
+
+/*
+ * Raid 6 recover code copied from kernel lib/raid6/recov.c
+ * - rename from raid6_datap_recov_intx1()
+ * - parameter changed from faila to dest1
+ */
+int raid6_recov_datap(int nr_devs, size_t stripe_len, int dest1, void **data)
+{
+       u8 *p, *q, *dq;
+       const u8 *qmul;         /* Q multiplier table */
+       char *zero_mem;
+
+       p = (u8 *)data[nr_devs - 2];
+       q = (u8 *)data[nr_devs - 1];
+
+       zero_mem = calloc(1, stripe_len);
+       if (!zero_mem)
+               return -ENOMEM;
+
+       /* Compute syndrome with zero for the missing data page
+          Use the dead data page as temporary storage for delta q */
+       dq = (u8 *)data[dest1];
+       data[dest1] = (void *)zero_mem;
+       data[nr_devs - 1] = dq;
+
+       raid6_gen_syndrome(nr_devs, stripe_len, data);
+
+       /* Restore pointer table */
+       data[dest1]   = dq;
+       data[nr_devs - 1] = q;
+
+       /* Now, pick the proper data tables */
+       qmul  = raid6_gfmul[raid6_gfinv[raid6_gfexp[dest1]]];
+
+       /* Now do it... */
+       while ( stripe_len-- ) {
+               *p++ ^= *dq = qmul[*q ^ *dq];
+               q++; dq++;
+       }
+       return 0;
+}
+
+/* Original raid56 recovery wrapper */
+int raid56_recov(int nr_devs, size_t stripe_len, u64 profile, int dest1,
+                int dest2, void **data)
+{
+       int min_devs;
+       int ret;
+
+       if (profile & BTRFS_BLOCK_GROUP_RAID5)
+               min_devs = 2;
+       else if (profile & BTRFS_BLOCK_GROUP_RAID6)
+               min_devs = 3;
+       else
+               return -EINVAL;
+       if (nr_devs < min_devs)
+               return -EINVAL;
+
+       /* Nothing to recover */
+       if (dest1 == -1 && dest2 == -1)
+               return 0;
+
+       /* Reorder dest1/2, so only dest2 can be -1  */
+       if (dest1 == -1) {
+               dest1 = dest2;
+               dest2 = -1;
+       } else if (dest2 != -1 && dest1 != -1) {
+               /* Reorder dest1/2, ensure dest2 > dest1 */
+               if (dest1 > dest2) {
+                       int tmp;
+
+                       tmp = dest2;
+                       dest2 = dest1;
+                       dest1 = tmp;
+               }
+       }
+
+       if (profile & BTRFS_BLOCK_GROUP_RAID5) {
+               if (dest2 != -1)
+                       return 1;
+               return raid5_gen_result(nr_devs, stripe_len, dest1, data);
+       }
+
+       /* RAID6 one dev corrupted case*/
+       if (dest2 == -1) {
+               /* Regenerate P/Q */
+               if (dest1 == nr_devs - 1 || dest1 == nr_devs - 2) {
+                       raid6_gen_syndrome(nr_devs, stripe_len, data);
+                       return 0;
+               }
+
+               /* Regerneate data from P */
+               return raid5_gen_result(nr_devs - 1, stripe_len, dest1, data);
+       }
+
+       /* P/Q bot corrupted */
+       if (dest1 == nr_devs - 2 && dest2 == nr_devs - 1) {
+               raid6_gen_syndrome(nr_devs, stripe_len, data);
+               return 0;
+       }
+
+       /* 2 Data corrupted */
+       if (dest2 < nr_devs - 2)
+               return raid6_recov_data2(nr_devs, stripe_len, dest1, dest2,
+                                        data);
+       /* Data and P*/
+       if (dest2 == nr_devs - 1)
+               return raid6_recov_datap(nr_devs, stripe_len, dest1, data);
+
+       /*
+        * Final case, Data and Q, recover data first then regenerate Q
+        */
+       ret = raid5_gen_result(nr_devs - 1, stripe_len, dest1, data);
+       if (ret < 0)
+               return ret;
+       raid6_gen_syndrome(nr_devs, stripe_len, data);
+       return 0;
+}