Merge tag 'md-3.5' of git://neil.brown.name/md

Pull md updates from NeilBrown:
 "It's been a busy cycle for md - lots of fun stuff here..  if you like
  this kind of thing :-)

  Main features:
   - RAID10 arrays can be reshaped - adding and removing devices and
     changing chunks (not 'far' array though)
   - allow RAID5 arrays to be reshaped with a backup file (not tested
     yet, but the priciple works fine for RAID10).
   - arrays can be reshaped while a bitmap is present - you no longer
     need to remove it first
   - SSSE3 support for RAID6 syndrome calculations

  and of course a number of minor fixes etc."

* tag 'md-3.5' of git://neil.brown.name/md: (56 commits)
  md/bitmap: record the space available for the bitmap in the superblock.
  md/raid10: Remove extras after reshape to smaller number of devices.
  md/raid5: improve removal of extra devices after reshape.
  md: check the return of mddev_find()
  MD RAID1: Further conditionalize 'fullsync'
  DM RAID: Use md_error() in place of simply setting Faulty bit
  DM RAID: Record and handle missing devices
  DM RAID: Set recovery flags on resume
  md/raid5: Allow reshape while a bitmap is present.
  md/raid10: resize bitmap when required during reshape.
  md: allow array to be resized while bitmap is present.
  md/bitmap: make sure reshape request are reflected in superblock.
  md/bitmap: add bitmap_resize function to allow bitmap resizing.
  md/bitmap: use DIV_ROUND_UP instead of open-code
  md/bitmap: create a 'struct bitmap_counts' substructure of 'struct bitmap'
  md/bitmap: make bitmap bitops atomic.
  md/bitmap: make _page_attr bitops atomic.
  md/bitmap: merge bitmap_file_unmap and bitmap_file_put.
  md/bitmap: remove async freeing of bitmap file.
  md/bitmap: convert some spin_lock_irqsave to spin_lock_irq
  ...

2 files changed, 29 insertions, 4 deletions

diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index 8c0a3adc5df5..ee753536ab70 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -233,7 +233,10 @@ struct mdp_superblock_1 {
         __le32  delta_disks;    /* change in number of raid_disks               */
         __le32  new_layout;     /* new layout                                   */
         __le32  new_chunk;      /* new chunk size (512byte sectors)             */
-        __u8    pad1[128-124];  /* set to 0 when written */
+        __le32  new_offset;     /* signed number to add to data_offset in new
+                                 * layout.  0 == no-change.  This can be
+                                 * different on each device in the array.
+                                 */
 
         /* constant this-device information - 64 bytes */
         __le64  data_offset;    /* sector start of data, often 0 */
@@ -281,10 +284,18 @@ struct mdp_superblock_1 {
                                             * active device with same 'role'.
                                             * 'recovery_offset' is also set.
                                             */
+#define MD_FEATURE_RESHAPE_BACKWARDS    32 /* Reshape doesn't change number
+                                            * of devices, but is going
+                                            * backwards anyway.
+                                            */
+#define MD_FEATURE_NEW_OFFSET           64 /* new_offset must be honoured */
 #define MD_FEATURE_ALL                  (MD_FEATURE_BITMAP_OFFSET       \
                                         |MD_FEATURE_RECOVERY_OFFSET     \
                                         |MD_FEATURE_RESHAPE_ACTIVE      \
                                         |MD_FEATURE_BAD_BLOCKS          \
-                                        |MD_FEATURE_REPLACEMENT)
+                                        |MD_FEATURE_REPLACEMENT         \
+                                        |MD_FEATURE_RESHAPE_BACKWARDS   \
+                                        |MD_FEATURE_NEW_OFFSET          \
+                                        )
 
 #endif 
diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 53272e9860a7..640c69ceec96 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -99,8 +99,20 @@ extern const struct raid6_calls raid6_altivec2;
 extern const struct raid6_calls raid6_altivec4;
 extern const struct raid6_calls raid6_altivec8;
 
+struct raid6_recov_calls {
+        void (*data2)(int, size_t, int, int, void **);
+        void (*datap)(int, size_t, int, void **);
+        int  (*valid)(void);
+        const char *name;
+        int priority;
+};
+
+extern const struct raid6_recov_calls raid6_recov_intx1;
+extern const struct raid6_recov_calls raid6_recov_ssse3;
+
 /* Algorithm list */
 extern const struct raid6_calls * const raid6_algos[];
+extern const struct raid6_recov_calls *const raid6_recov_algos[];
 int raid6_select_algo(void);
 
 /* Return values from chk_syndrome */
@@ -111,14 +123,16 @@ int raid6_select_algo(void);
 
 /* Galois field tables */
 extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
+extern const u8 raid6_vgfmul[256][32] __attribute__((aligned(256)));
 extern const u8 raid6_gfexp[256]      __attribute__((aligned(256)));
 extern const u8 raid6_gfinv[256]      __attribute__((aligned(256)));
 extern const u8 raid6_gfexi[256]      __attribute__((aligned(256)));
 
 /* Recovery routines */
-void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
+extern void (*raid6_2data_recov)(int disks, size_t bytes, int faila, int failb,
                        void **ptrs);
-void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs);
+extern void (*raid6_datap_recov)(int disks, size_t bytes, int faila,
+                        void **ptrs);
 void raid6_dual_recov(int disks, size_t bytes, int faila, int failb,
                       void **ptrs);