1 files changed, 55 insertions, 43 deletions

diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index e10c5531f9c5..8d8e13934a48 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -27,7 +27,7 @@
  * The possible state transitions are:
  *
  *  Empty -> Want   - on read or write to get old data for  parity calc
- *  Empty -> Dirty  - on compute_parity to satisfy write/sync request.(RECONSTRUCT_WRITE)
+ *  Empty -> Dirty  - on compute_parity to satisfy write/sync request.
  *  Empty -> Clean  - on compute_block when computing a block for failed drive
  *  Want  -> Empty  - on failed read
  *  Want  -> Clean  - on successful completion of read request
@@ -226,8 +226,11 @@ struct stripe_head {
                 #endif
         } ops;
         struct r5dev {
-                struct bio      req;
-                struct bio_vec  vec;
+                /* rreq and rvec are used for the replacement device when
+                 * writing data to both devices.
+                 */
+                struct bio      req, rreq;
+                struct bio_vec  vec, rvec;
                 struct page     *page;
                 struct bio      *toread, *read, *towrite, *written;
                 sector_t        sector;                 /* sector of this page */
@@ -239,7 +242,13 @@ struct stripe_head {
  *     for handle_stripe.
  */
 struct stripe_head_state {
-        int syncing, expanding, expanded;
+        /* 'syncing' means that we need to read all devices, either
+         * to check/correct parity, or to reconstruct a missing device.
+         * 'replacing' means we are replacing one or more drives and
+         * the source is valid at this point so we don't need to
+         * read all devices, just the replacement targets.
+         */
+        int syncing, expanding, expanded, replacing;
         int locked, uptodate, to_read, to_write, failed, written;
         int to_fill, compute, req_compute, non_overwrite;
         int failed_num[2];
@@ -252,38 +261,41 @@ struct stripe_head_state {
         int handle_bad_blocks;
 };
 
-/* Flags */
-#define R5_UPTODATE     0       /* page contains current data */
-#define R5_LOCKED       1       /* IO has been submitted on "req" */
-#define R5_OVERWRITE    2       /* towrite covers whole page */
+/* Flags for struct r5dev.flags */
+enum r5dev_flags {
+        R5_UPTODATE,    /* page contains current data */
+        R5_LOCKED,      /* IO has been submitted on "req" */
+        R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */
+        R5_OVERWRITE,   /* towrite covers whole page */
 /* and some that are internal to handle_stripe */
-#define R5_Insync       3       /* rdev && rdev->in_sync at start */
-#define R5_Wantread     4       /* want to schedule a read */
-#define R5_Wantwrite    5
-#define R5_Overlap      7       /* There is a pending overlapping request on this block */
-#define R5_ReadError    8       /* seen a read error here recently */
-#define R5_ReWrite      9       /* have tried to over-write the readerror */
+        R5_Insync,      /* rdev && rdev->in_sync at start */
+        R5_Wantread,    /* want to schedule a read */
+        R5_Wantwrite,
+        R5_Overlap,     /* There is a pending overlapping request
+                         * on this block */
+        R5_ReadError,   /* seen a read error here recently */
+        R5_ReWrite,     /* have tried to over-write the readerror */
 
-#define R5_Expanded     10      /* This block now has post-expand data */
-#define R5_Wantcompute  11      /* compute_block in progress treat as
-                                 * uptodate
-                                 */
-#define R5_Wantfill     12      /* dev->toread contains a bio that needs
-                                 * filling
-                                 */
-#define R5_Wantdrain    13      /* dev->towrite needs to be drained */
-#define R5_WantFUA      14      /* Write should be FUA */
-#define R5_WriteError   15      /* got a write error - need to record it */
-#define R5_MadeGood     16      /* A bad block has been fixed by writing to it*/
-/*
- * Write method
- */
-#define RECONSTRUCT_WRITE       1
-#define READ_MODIFY_WRITE       2
-/* not a write method, but a compute_parity mode */
-#define CHECK_PARITY            3
-/* Additional compute_parity mode -- updates the parity w/o LOCKING */
-#define UPDATE_PARITY           4
+        R5_Expanded,    /* This block now has post-expand data */
+        R5_Wantcompute, /* compute_block in progress treat as
+                         * uptodate
+                         */
+        R5_Wantfill,    /* dev->toread contains a bio that needs
+                         * filling
+                         */
+        R5_Wantdrain,   /* dev->towrite needs to be drained */
+        R5_WantFUA,     /* Write should be FUA */
+        R5_WriteError,  /* got a write error - need to record it */
+        R5_MadeGood,    /* A bad block has been fixed by writing to it */
+        R5_ReadRepl,    /* Will/did read from replacement rather than orig */
+        R5_MadeGoodRepl,/* A bad block on the replacement device has been
+                         * fixed by writing to it */
+        R5_NeedReplace, /* This device has a replacement which is not
+                         * up-to-date at this stripe. */
+        R5_WantReplace, /* We need to update the replacement, we have read
+                         * data in, and now is a good time to write it out.
+                         */
+};
 
 /*
  * Stripe state
@@ -311,13 +323,14 @@ enum {
 /*
  * Operation request flags
  */
-#define STRIPE_OP_BIOFILL       0
-#define STRIPE_OP_COMPUTE_BLK   1
-#define STRIPE_OP_PREXOR        2
-#define STRIPE_OP_BIODRAIN      3
-#define STRIPE_OP_RECONSTRUCT   4
-#define STRIPE_OP_CHECK 5
-
+enum {
+        STRIPE_OP_BIOFILL,
+        STRIPE_OP_COMPUTE_BLK,
+        STRIPE_OP_PREXOR,
+        STRIPE_OP_BIODRAIN,
+        STRIPE_OP_RECONSTRUCT,
+        STRIPE_OP_CHECK,
+};
 /*
  * Plugging:
  *
@@ -344,13 +357,12 @@ enum {
 
 
 struct disk_info {
-        struct md_rdev  *rdev;
+        struct md_rdev  *rdev, *replacement;
 };
 
 struct r5conf {
         struct hlist_head       *stripe_hashtbl;
         struct mddev            *mddev;
-        struct disk_info        *spare;
         int                     chunk_sectors;
         int                     level, algorithm;
         int                     max_degraded;