6 files changed, 337 insertions, 7 deletions

diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h
new file mode 100644
index 0000000000..e24b74b111
--- /dev/null
+++ b/include/linux/raid/bitmap.h
@@ -0,0 +1,273 @@
+/*
+ * bitmap.h: Copyright (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
+ *
+ * additions: Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
+ */
+#ifndef BITMAP_H
+#define BITMAP_H 1
+
+#define BITMAP_MAJOR 3
+#define BITMAP_MINOR 38
+
+/*
+ * in-memory bitmap:
+ *
+ * Use 16 bit block counters to track pending writes to each "chunk".
+ * The 2 high order bits are special-purpose, the first is a flag indicating
+ * whether a resync is needed.  The second is a flag indicating whether a
+ * resync is active.
+ * This means that the counter is actually 14 bits:
+ *
+ * +--------+--------+------------------------------------------------+
+ * | resync | resync |               counter                          |
+ * | needed | active |                                                |
+ * |  (0-1) |  (0-1) |              (0-16383)                         |
+ * +--------+--------+------------------------------------------------+
+ *
+ * The "resync needed" bit is set when:
+ *    a '1' bit is read from storage at startup.
+ *    a write request fails on some drives
+ *    a resync is aborted on a chunk with 'resync active' set
+ * It is cleared (and resync-active set) when a resync starts across all drives
+ * of the chunk.
+ *
+ *
+ * The "resync active" bit is set when:
+ *    a resync is started on all drives, and resync_needed is set.
+ *       resync_needed will be cleared (as long as resync_active wasn't already set).
+ * It is cleared when a resync completes.
+ *
+ * The counter counts pending write requests, plus the on-disk bit.
+ * When the counter is '1' and the resync bits are clear, the on-disk
+ * bit can be cleared aswell, thus setting the counter to 0.
+ * When we set a bit, or in the counter (to start a write), if the fields is
+ * 0, we first set the disk bit and set the counter to 1.
+ *
+ * If the counter is 0, the on-disk bit is clear and the stipe is clean
+ * Anything that dirties the stipe pushes the counter to 2 (at least)
+ * and sets the on-disk bit (lazily).
+ * If a periodic sweep find the counter at 2, it is decremented to 1.
+ * If the sweep find the counter at 1, the on-disk bit is cleared and the
+ * counter goes to zero.
+ *
+ * Also, we'll hijack the "map" pointer itself and use it as two 16 bit block
+ * counters as a fallback when "page" memory cannot be allocated:
+ *
+ * Normal case (page memory allocated):
+ *
+ *     page pointer (32-bit)
+ *
+ *     [ ] ------+
+ *               |
+ *               +-------> [   ][   ]..[   ] (4096 byte page == 2048 counters)
+ *                          c1   c2    c2048
+ *
+ * Hijacked case (page memory allocation failed):
+ *
+ *     hijacked page pointer (32-bit)
+ *
+ *     [                  ][              ] (no page memory allocated)
+ *      counter #1 (16-bit) counter #2 (16-bit)
+ *
+ */
+
+#ifdef __KERNEL__
+
+#define PAGE_BITS (PAGE_SIZE << 3)
+#define PAGE_BIT_SHIFT (PAGE_SHIFT + 3)
+
+typedef __u16 bitmap_counter_t;
+#define COUNTER_BITS 16
+#define COUNTER_BIT_SHIFT 4
+#define COUNTER_BYTE_RATIO (COUNTER_BITS / 8)
+#define COUNTER_BYTE_SHIFT (COUNTER_BIT_SHIFT - 3)
+
+#define NEEDED_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 1)))
+#define RESYNC_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 2)))
+#define COUNTER_MAX ((bitmap_counter_t) RESYNC_MASK - 1)
+#define NEEDED(x) (((bitmap_counter_t) x) & NEEDED_MASK)
+#define RESYNC(x) (((bitmap_counter_t) x) & RESYNC_MASK)
+#define COUNTER(x) (((bitmap_counter_t) x) & COUNTER_MAX)
+
+/* how many counters per page? */
+#define PAGE_COUNTER_RATIO (PAGE_BITS / COUNTER_BITS)
+/* same, except a shift value for more efficient bitops */
+#define PAGE_COUNTER_SHIFT (PAGE_BIT_SHIFT - COUNTER_BIT_SHIFT)
+/* same, except a mask value for more efficient bitops */
+#define PAGE_COUNTER_MASK  (PAGE_COUNTER_RATIO - 1)
+
+#define BITMAP_BLOCK_SIZE 512
+#define BITMAP_BLOCK_SHIFT 9
+
+/* how many blocks per chunk? (this is variable) */
+#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->chunksize >> BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_SHIFT(bitmap) ((bitmap)->chunkshift - BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_MASK(bitmap) (CHUNK_BLOCK_RATIO(bitmap) - 1)
+
+/* when hijacked, the counters and bits represent even larger "chunks" */
+/* there will be 1024 chunks represented by each counter in the page pointers */
+#define PAGEPTR_BLOCK_RATIO(bitmap) \
+                        (CHUNK_BLOCK_RATIO(bitmap) << PAGE_COUNTER_SHIFT >> 1)
+#define PAGEPTR_BLOCK_SHIFT(bitmap) \
+                        (CHUNK_BLOCK_SHIFT(bitmap) + PAGE_COUNTER_SHIFT - 1)
+#define PAGEPTR_BLOCK_MASK(bitmap) (PAGEPTR_BLOCK_RATIO(bitmap) - 1)
+
+/*
+ * on-disk bitmap:
+ *
+ * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
+ * file a page at a time. There's a superblock at the start of the file.
+ */
+
+/* map chunks (bits) to file pages - offset by the size of the superblock */
+#define CHUNK_BIT_OFFSET(chunk) ((chunk) + (sizeof(bitmap_super_t) << 3))
+
+#endif
+
+/*
+ * bitmap structures:
+ */
+
+#define BITMAP_MAGIC 0x6d746962
+
+/* use these for bitmap->flags and bitmap->sb->state bit-fields */
+enum bitmap_state {
+        BITMAP_ACTIVE = 0x001, /* the bitmap is in use */
+        BITMAP_STALE  = 0x002  /* the bitmap file is out of date or had -EIO */
+};
+
+/* the superblock at the front of the bitmap file -- little endian */
+typedef struct bitmap_super_s {
+        __u32 magic;        /*  0  BITMAP_MAGIC */
+        __u32 version;      /*  4  the bitmap major for now, could change... */
+        __u8  uuid[16];     /*  8  128 bit uuid - must match md device uuid */
+        __u64 events;       /* 24  event counter for the bitmap (1)*/
+        __u64 events_cleared;/*32  event counter when last bit cleared (2) */
+        __u64 sync_size;    /* 40  the size of the md device's sync range(3) */
+        __u32 state;        /* 48  bitmap state information */
+        __u32 chunksize;    /* 52  the bitmap chunk size in bytes */
+        __u32 daemon_sleep; /* 56  seconds between disk flushes */
+
+        __u8  pad[256 - 60]; /* set to zero */
+} bitmap_super_t;
+
+/* notes:
+ * (1) This event counter is updated before the eventcounter in the md superblock
+ *    When a bitmap is loaded, it is only accepted if this event counter is equal
+ *    to, or one greater than, the event counter in the superblock.
+ * (2) This event counter is updated when the other one is *if*and*only*if* the
+ *    array is not degraded.  As bits are not cleared when the array is degraded,
+ *    this represents the last time that any bits were cleared.
+ *    If a device is being added that has an event count with this value or
+ *    higher, it is accepted as conforming to the bitmap.
+ * (3)This is the number of sectors represented by the bitmap, and is the range that
+ *    resync happens across.  For raid1 and raid5/6 it is the size of individual
+ *    devices.  For raid10 it is the size of the array.
+ */
+
+#ifdef __KERNEL__
+
+/* the in-memory bitmap is represented by bitmap_pages */
+struct bitmap_page {
+        /*
+         * map points to the actual memory page
+         */
+        char *map;
+        /*
+         * in emergencies (when map cannot be alloced), hijack the map
+         * pointer and use it as two counters itself
+         */
+        unsigned int hijacked:1;
+        /*
+         * count of dirty bits on the page
+         */
+        unsigned int  count:31;
+};
+
+/* keep track of bitmap file pages that have pending writes on them */
+struct page_list {
+        struct list_head list;
+        struct page *page;
+};
+
+/* the main bitmap structure - one per mddev */
+struct bitmap {
+        struct bitmap_page *bp;
+        unsigned long pages; /* total number of pages in the bitmap */
+        unsigned long missing_pages; /* number of pages not yet allocated */
+
+        mddev_t *mddev; /* the md device that the bitmap is for */
+
+        int counter_bits; /* how many bits per block counter */
+
+        /* bitmap chunksize -- how much data does each bit represent? */
+        unsigned long chunksize;
+        unsigned long chunkshift; /* chunksize = 2^chunkshift (for bitops) */
+        unsigned long chunks; /* total number of data chunks for the array */
+
+        /* We hold a count on the chunk currently being synced, and drop
+         * it when the last block is started.  If the resync is aborted
+         * midway, we need to be able to drop that count, so we remember
+         * the counted chunk..
+         */
+        unsigned long syncchunk;
+
+        __u64   events_cleared;
+
+        /* bitmap spinlock */
+        spinlock_t lock;
+
+        long offset; /* offset from superblock if file is NULL */
+        struct file *file; /* backing disk file */
+        struct page *sb_page; /* cached copy of the bitmap file superblock */
+        struct page **filemap; /* list of cache pages for the file */
+        unsigned long *filemap_attr; /* attributes associated w/ filemap pages */
+        unsigned long file_pages; /* number of pages in the file */
+
+        unsigned long flags;
+
+        /*
+         * the bitmap daemon - periodically wakes up and sweeps the bitmap
+         * file, cleaning up bits and flushing out pages to disk as necessary
+         */
+        unsigned long daemon_lastrun; /* jiffies of last run */
+        unsigned long daemon_sleep; /* how many seconds between updates? */
+
+        /*
+         * bitmap_writeback_daemon waits for file-pages that have been written,
+         * as there is no way to get a call-back when a page write completes.
+         */
+        mdk_thread_t *writeback_daemon;
+        spinlock_t write_lock;
+        wait_queue_head_t write_wait;
+        struct list_head complete_pages;
+        mempool_t *write_pool;
+};
+
+/* the bitmap API */
+
+/* these are used only by md/bitmap */
+int  bitmap_create(mddev_t *mddev);
+void bitmap_destroy(mddev_t *mddev);
+int  bitmap_active(struct bitmap *bitmap);
+
+char *file_path(struct file *file, char *buf, int count);
+void bitmap_print_sb(struct bitmap *bitmap);
+int bitmap_update_sb(struct bitmap *bitmap);
+
+int  bitmap_setallbits(struct bitmap *bitmap);
+void bitmap_write_all(struct bitmap *bitmap);
+
+/* these are exported */
+int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors);
+void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
+                     int success);
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks);
+void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted);
+void bitmap_close_sync(struct bitmap *bitmap);
+
+int bitmap_unplug(struct bitmap *bitmap);
+int bitmap_daemon_work(struct bitmap *bitmap);
+#endif
+
+#endif
diff --git a/include/linux/raid/md.h b/include/linux/raid/md.h
index a6a67d102b..ffa316ce4d 100644
--- a/include/linux/raid/md.h
+++ b/include/linux/raid/md.h
@@ -60,7 +60,14 @@
  */
 #define MD_MAJOR_VERSION                0
 #define MD_MINOR_VERSION                90
-#define MD_PATCHLEVEL_VERSION           1
+/*
+ * MD_PATCHLEVEL_VERSION indicates kernel functionality.
+ * >=1 means different superblock formats are selectable using SET_ARRAY_INFO
+ *     and major_version/minor_version accordingly
+ * >=2 means that Internal bitmaps are supported by setting MD_SB_BITMAP_PRESENT
+ *     in the super status byte
+ */
+#define MD_PATCHLEVEL_VERSION           2
 
 extern int register_md_personality (int p_num, mdk_personality_t *p);
 extern int unregister_md_personality (int p_num);
@@ -69,7 +76,7 @@ extern mdk_thread_t * md_register_thread (void (*run) (mddev_t *mddev),
 extern void md_unregister_thread (mdk_thread_t *thread);
 extern void md_wakeup_thread(mdk_thread_t *thread);
 extern void md_check_recovery(mddev_t *mddev);
-extern void md_write_start(mddev_t *mddev);
+extern void md_write_start(mddev_t *mddev, struct bio *bi);
 extern void md_write_end(mddev_t *mddev);
 extern void md_handle_safemode(mddev_t *mddev);
 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
@@ -78,6 +85,12 @@ extern void md_unplug_mddev(mddev_t *mddev);
 
 extern void md_print_devices (void);
 
+extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
+                           sector_t sector, int size, struct page *page);
+extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
+                        struct page *page, int rw);
+
+
 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
 
 #endif 
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index c9a0d4013b..8c14ba565a 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -15,6 +15,9 @@
 #ifndef _MD_K_H
 #define _MD_K_H
 
+/* and dm-bio-list.h is not under include/linux because.... ??? */
+#include "../../../drivers/md/dm-bio-list.h"
+
 #define MD_RESERVED       0UL
 #define LINEAR            1UL
 #define RAID0             2UL
@@ -180,6 +183,10 @@ struct mdk_rdev_s
 
         int desc_nr;                    /* descriptor index in the superblock */
         int raid_disk;                  /* role of device in array */
+        int saved_raid_disk;            /* role that device used to have in the
+                                         * array and could again if we did a partial
+                                         * resync from the bitmap
+                                         */
 
         atomic_t        nr_pending;     /* number of pending requests.
                                          * only maintained for arrays that
@@ -252,6 +259,11 @@ struct mddev_s
         atomic_t                        recovery_active; /* blocks scheduled, but not written */
         wait_queue_head_t               recovery_wait;
         sector_t                        recovery_cp;
+
+        spinlock_t                      write_lock;
+        wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
+        atomic_t                        pending_writes; /* number of active superblock writes */
+
         unsigned int                    safemode;       /* if set, update "clean" superblock
                                                          * when no writes pending.
                                                          */ 
@@ -260,6 +272,13 @@ struct mddev_s
         atomic_t                        writes_pending; 
         request_queue_t                 *queue; /* for plugging ... */
 
+        struct bitmap                   *bitmap; /* the bitmap for the device */
+        struct file                     *bitmap_file; /* the bitmap file */
+        long                            bitmap_offset; /* offset from superblock of
+                                                        * start of bitmap. May be
+                                                        * negative, but not '0'
+                                                        */
+
         struct list_head                all_mddevs;
 };
 
@@ -291,7 +310,7 @@ struct mdk_personality_s
         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
         int (*hot_remove_disk) (mddev_t *mddev, int number);
         int (*spare_active) (mddev_t *mddev);
-        int (*sync_request)(mddev_t *mddev, sector_t sector_nr, int go_faster);
+        sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
         int (*resize) (mddev_t *mddev, sector_t sectors);
         int (*reshape) (mddev_t *mddev, int raid_disks);
         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
@@ -334,6 +353,7 @@ typedef struct mdk_thread_s {
         unsigned long           flags;
         struct completion       *event;
         struct task_struct      *tsk;
+        unsigned long           timeout;
         const char              *name;
 } mdk_thread_t;
 
diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index 8ba95d6732..dc65cd4354 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -96,6 +96,7 @@ typedef struct mdp_device_descriptor_s {
 #define MD_SB_CLEAN             0
 #define MD_SB_ERRORS            1
 
+#define MD_SB_BITMAP_PRESENT    8 /* bitmap may be present nearby */
 typedef struct mdp_superblock_s {
         /*
          * Constant generic information
@@ -184,7 +185,7 @@ struct mdp_superblock_1 {
         /* constant array information - 128 bytes */
         __u32   magic;          /* MD_SB_MAGIC: 0xa92b4efc - little endian */
         __u32   major_version;  /* 1 */
-        __u32   feature_map;    /* 0 for now */
+        __u32   feature_map;    /* bit 0 set if 'bitmap_offset' is meaningful */
         __u32   pad0;           /* always set to 0 when writing */
 
         __u8    set_uuid[16];   /* user-space generated. */
@@ -197,7 +198,11 @@ struct mdp_superblock_1 {
 
         __u32   chunksize;      /* in 512byte sectors */
         __u32   raid_disks;
-        __u8    pad1[128-96];   /* set to 0 when written */
+        __u32   bitmap_offset;  /* sectors after start of superblock that bitmap starts
+                                 * NOTE: signed, so bitmap can be before superblock
+                                 * only meaningful of feature_map[0] is set.
+                                 */
+        __u8    pad1[128-100];  /* set to 0 when written */
 
         /* constant this-device information - 64 bytes */
         __u64   data_offset;    /* sector start of data, often 0 */
diff --git a/include/linux/raid/md_u.h b/include/linux/raid/md_u.h
index a2df5c2a42..81da20ccec 100644
--- a/include/linux/raid/md_u.h
+++ b/include/linux/raid/md_u.h
@@ -23,6 +23,7 @@
 #define GET_DISK_INFO           _IOR (MD_MAJOR, 0x12, mdu_disk_info_t)
 #define PRINT_RAID_DEBUG        _IO (MD_MAJOR, 0x13)
 #define RAID_AUTORUN            _IO (MD_MAJOR, 0x14)
+#define GET_BITMAP_FILE         _IOR (MD_MAJOR, 0x15, mdu_bitmap_file_t)
 
 /* configuration */
 #define CLEAR_ARRAY             _IO (MD_MAJOR, 0x20)
@@ -36,6 +37,7 @@
 #define HOT_ADD_DISK            _IO (MD_MAJOR, 0x28)
 #define SET_DISK_FAULTY         _IO (MD_MAJOR, 0x29)
 #define HOT_GENERATE_ERROR      _IO (MD_MAJOR, 0x2a)
+#define SET_BITMAP_FILE         _IOW (MD_MAJOR, 0x2b, int)
 
 /* usage */
 #define RUN_ARRAY               _IOW (MD_MAJOR, 0x30, mdu_param_t)
@@ -106,6 +108,11 @@ typedef struct mdu_start_info_s {
 
 } mdu_start_info_t;
 
+typedef struct mdu_bitmap_file_s
+{
+        char pathname[4096];
+} mdu_bitmap_file_t;
+
 typedef struct mdu_param_s
 {
         int                     personality;    /* 1,2,3,4 */
diff --git a/include/linux/raid/raid1.h b/include/linux/raid/raid1.h
index abbfdd9afe..9d93cf12e8 100644
--- a/include/linux/raid/raid1.h
+++ b/include/linux/raid/raid1.h
@@ -36,12 +36,21 @@ struct r1_private_data_s {
         spinlock_t              device_lock;
 
         struct list_head        retry_list;
+        /* queue pending writes and submit them on unplug */
+        struct bio_list         pending_bio_list;
+        /* queue of writes that have been unplugged */
+        struct bio_list         flushing_bio_list;
+
         /* for use when syncing mirrors: */
 
         spinlock_t              resync_lock;
-        int nr_pending;
-        int barrier;
+        int                     nr_pending;
+        int                     barrier;
         sector_t                next_resync;
+        int                     fullsync;  /* set to 1 if a full sync is needed,
+                                            * (fresh device added).
+                                            * Cleared when a sync completes.
+                                            */
 
         wait_queue_head_t       wait_idle;
         wait_queue_head_t       wait_resume;
@@ -85,14 +94,17 @@ struct r1bio_s {
         int                     read_disk;
 
         struct list_head        retry_list;
+        struct bitmap_update    *bitmap_update;
         /*
          * if the IO is in WRITE direction, then multiple bios are used.
          * We choose the number when they are allocated.
          */
         struct bio              *bios[0];
+        /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
 };
 
 /* bits for r1bio.state */
 #define R1BIO_Uptodate  0
 #define R1BIO_IsSync    1
+#define R1BIO_Degraded  2
 #endif