* grub-core/fs/zfs/zfs.c (read_device): Add ability to sustain a single

	drive failure on both raidz and raidz2.

diff --git a/ChangeLog b/ChangeLog
index 08bad81c6914f5820595c495549ac8219f0e3879..047c156c7683f858161b47fb61a8d7e8d0fbaf60 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-11-02  Vladimir Serbinenko  <phcoder@gmail.com>
+
+       * grub-core/fs/zfs/zfs.c (read_device): Add ability to sustain a single
+       drive failure on both raidz and raidz2.
+
 2011-11-02  Vladimir Serbinenko  <phcoder@gmail.com>
 
        Fix RAIDZ(2) for >= 5 devices.

diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c
index 1c9b240ab85d88248dfa9bc5dd20eb2f09e0f388..1bfbed72c942dfd499acf63cf082b58e27924b94 100644 (file)
--- a/grub-core/fs/zfs/zfs.c
+++ b/grub-core/fs/zfs/zfs.c
@@ -850,6 +850,14 @@ scan_devices (struct grub_zfs_data *data)
   return GRUB_ERR_NONE;
 }
 
+static inline void
+xor (grub_uint64_t *a, const grub_uint64_t *b, grub_size_t s)
+{
+  s /= sizeof (grub_uint64_t);
+  while (s--)
+    *a++ ^= *b++;
+}
+
 static grub_err_t
 read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
             grub_size_t len, void *buf)
@@ -889,40 +897,26 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
        unsigned c = 0;
        grub_uint64_t high;
        grub_uint64_t devn;
-       grub_uint64_t redundancy_strip = 0, m;
-       grub_uint64_t redundancy_strip2 = 0;
-       grub_uint32_t s;
+       grub_uint64_t m;
+       grub_uint32_t s, orig_s;
+       void *orig_buf = buf;
+       grub_size_t orig_len = len;
+       void *recovery_buf = NULL;
+       grub_size_t recovery_len = 0;
 
        if (desc->nparity < 1 || desc->nparity > 2)
          return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, 
                             "raidz%d is not supported", desc->nparity);
 
-       s = (((len + (1 << desc->ashift) - 1) >> desc->ashift)
-            + (desc->n_children - desc->nparity) - 1);
+       orig_s = (((len + (1 << desc->ashift) - 1) >> desc->ashift)
+                 + (desc->n_children - desc->nparity) - 1);
+       s = orig_s;
 
        high = grub_divmod64 ((offset >> desc->ashift),
                              desc->n_children, &m);
 
-
-       switch (desc->nparity)
-         {
-         case 1:
-           redundancy_strip = m;
-           redundancy_strip += ((offset >> (desc->ashift + 11)) & 1);
-           if (redundancy_strip == desc->n_children)
-             redundancy_strip = 0;
-           redundancy_strip2 = redundancy_strip;
-           break;
-         case 2:
-           redundancy_strip = m;
-           redundancy_strip2 = m + 1;
-           if (redundancy_strip2 == desc->n_children)
-             redundancy_strip2 = 0;
-           break;
-         }
-       grub_dprintf ("zfs", "rs = %x, %llx\n",
-                     (int) redundancy_strip,
-                     (unsigned long long) high);
+       if (desc->nparity == 2)
+         c = 2;
        while (len > 0)
          {
            grub_size_t csize;
@@ -930,15 +924,12 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
            grub_err_t err;
            bsize = s / (desc->n_children - desc->nparity);
 
-           while (1)
-             {
-               high = grub_divmod64 ((offset >> desc->ashift) + c,
-                                     desc->n_children, &devn);
-               if (devn != redundancy_strip && devn != redundancy_strip2)
-                 break;
-               c++;
-             }
+           if (desc->nparity == 1
+               && ((offset >> (desc->ashift + 11)) & 1) == c)
+             c++;
 
+           high = grub_divmod64 ((offset >> desc->ashift) + c,
+                                 desc->n_children, &devn);
            csize = bsize << desc->ashift;
            if (csize > len)
              csize = len;
@@ -953,6 +944,13 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
                               | (offset & ((1 << desc->ashift) - 1)),
                               &desc->children[devn],
                               csize, buf);
+           /* No raidz2 recovery yet.  */
+           if (err && recovery_len == 0)
+             {
+               recovery_buf = buf;
+               recovery_len = csize;
+               grub_errno = err = 0;
+             }
            if (err)
              return err;
 
@@ -961,8 +959,42 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
            buf = (char *) buf + csize;
            len -= csize;
          }
+       if (recovery_buf)
+         {
+           grub_err_t err;
+           high = grub_divmod64 ((offset >> desc->ashift)
+                                 + 
+                                 ((desc->nparity == 1)
+                                  && ((offset >> (desc->ashift + 11)) & 1)),
+                                 desc->n_children, &devn);
+           err = read_device ((high << desc->ashift)
+                              | (offset & ((1 << desc->ashift) - 1)),
+                              &desc->children[devn],
+                              recovery_len, recovery_buf);
+           if (err)
+             return err;
+           buf = orig_buf;
+           len = orig_len;
+           s = orig_s;
+           while (len > 0)
+             {
+               grub_size_t csize;
+               csize = ((s / (desc->n_children - desc->nparity))
+                        << desc->ashift);
+               if (csize > len)
+                 csize = len;
+
+               if (buf != recovery_buf)
+                 xor (recovery_buf, buf,
+                      csize < recovery_len ? csize : recovery_len);
+
+               s--;
+               buf = (char *) buf + csize;
+               len -= csize;
+             }     
+         }
+       return GRUB_ERR_NONE;
       }
-      return GRUB_ERR_NONE;        
     }
   return grub_error (GRUB_ERR_BAD_FS, "unsupported device type");
 }