]> git.ipfire.org Git - thirdparty/mdadm.git/blobdiff - super1.c
Just updaqte copyright dates and email address
[thirdparty/mdadm.git] / super1.c
index e4a5e0d12568e2cbff7a38905859899afb3be070..cc0a5e3003194b4e38de66c8566a728d3b06a45f 100644 (file)
--- a/super1.c
+++ b/super1.c
@@ -1,7 +1,7 @@
 /*
  * mdadm - manage Linux "md" devices aka RAID arrays.
  *
- * Copyright (C) 2001-2004 Neil Brown <neilb@cse.unsw.edu.au>
+ * Copyright (C) 2001-2006 Neil Brown <neilb@suse.de>
  *
  *
  *    This program is free software; you can redistribute it and/or modify
@@ -28,8 +28,6 @@
  */
 
 #include "mdadm.h"
-#include <endian.h>
-#include "asm/byteorder.h"
 /*
  * The version-1 superblock :
  * All numeric fields are little-endian.
@@ -58,7 +56,14 @@ struct mdp_superblock_1 {
                                 * 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 */
+
+       /* These are only valid with feature bit '4' */
+       __u32   new_level;      /* new level we are reshaping to                */
+       __u64   reshape_position;       /* next address in array-space for reshape */
+       __u32   delta_disks;    /* change in number of raid_disks               */
+       __u32   new_layout;     /* new layout                                   */
+       __u32   new_chunk;      /* new chunk size (bytes)                       */
+       __u8    pad1[128-124];  /* set to 0 when written */
 
        /* constant this-device information - 64 bytes */
        __u64   data_offset;    /* sector start of data, often 0 */
@@ -94,8 +99,9 @@ struct mdp_superblock_1 {
 #define        MD_FEATURE_RECOVERY_OFFSET      2 /* recovery_offset is present and
                                           * must be honoured
                                           */
+#define        MD_FEATURE_RESHAPE_ACTIVE       4
 
-#define        MD_FEATURE_ALL                  (1|2)
+#define        MD_FEATURE_ALL                  (1|2|4)
 
 #ifndef offsetof
 #define offsetof(t,f) ((int)&(((t*)0)->f))
@@ -140,7 +146,8 @@ static void examine_super1(void *sbv)
        char *c;
 
        printf("          Magic : %08x\n", __le32_to_cpu(sb->magic));
-       printf("        Version : %02d.%02d\n", 1, __le32_to_cpu(sb->feature_map));
+       printf("        Version : %02d\n", 1);
+       printf("    Feature Map : 0x%x\n", __le32_to_cpu(sb->feature_map));
        printf("     Array UUID : ");
        for (i=0; i<16; i++) {
                if ((i&3)==0 && i != 0) printf(":");
@@ -156,8 +163,20 @@ static void examine_super1(void *sbv)
        printf("   Raid Devices : %d\n", __le32_to_cpu(sb->raid_disks));
        printf("\n");
        printf("    Device Size : %llu%s\n", (unsigned long long)sb->data_size, human_size(sb->data_size<<9));
-       if (sb->size != sb->data_size)
-               printf("      Used Size : %llu%s\n", (unsigned long long)sb->size, human_size(sb->size<<9));
+       if (__le32_to_cpu(sb->level) >= 0) {
+               int ddsks=0;
+               switch(__le32_to_cpu(sb->level)) {
+               case 1: ddsks=1;break;
+               case 4:
+               case 5: ddsks = sb->raid_disks-1; break;
+               case 6: ddsks = sb->raid_disks-2; break;
+               case 10: ddsks = sb->raid_disks / (sb->layout&255) / ((sb->layout>>8)&255);
+               }
+               if (ddsks)
+                       printf("     Array Size : %llu%s\n", ddsks*(unsigned long long)sb->size, human_size(ddsks*sb->size<<9));
+               if (sb->size != sb->data_size)
+                       printf("      Used Size : %llu%s\n", (unsigned long long)sb->size, human_size(sb->size<<9));
+       }
        if (sb->data_offset)
                printf("    Data Offset : %llu sectors\n", (unsigned long long)__le64_to_cpu(sb->data_offset));
        if (sb->super_offset)
@@ -171,6 +190,44 @@ static void examine_super1(void *sbv)
                printf("%02x", sb->device_uuid[i]);
        }
        printf("\n");
+       printf("\n");
+       if (sb->feature_map & __cpu_to_le32(MD_FEATURE_BITMAP_OFFSET)) {
+               printf("Internal Bitmap : %ld sectors from superblock\n",
+                      (long)__le32_to_cpu(sb->bitmap_offset));
+       }
+       if (sb->feature_map & __le32_to_cpu(MD_FEATURE_RESHAPE_ACTIVE)) {
+               printf("  Reshape pos'n : %llu%s\n", (unsigned long long)__le64_to_cpu(sb->reshape_position)/2,
+                      human_size(__le64_to_cpu(sb->reshape_position)<<9));
+               if (__le32_to_cpu(sb->delta_disks)) {
+                       printf("  Delta Devices : %d", __le32_to_cpu(sb->delta_disks));
+                       if (__le32_to_cpu(sb->delta_disks))
+                               printf(" (%d->%d)\n",
+                                      __le32_to_cpu(sb->raid_disks)-__le32_to_cpu(sb->delta_disks),
+                                      __le32_to_cpu(sb->raid_disks));
+                       else
+                               printf(" (%d->%d)\n", __le32_to_cpu(sb->raid_disks),
+                                      __le32_to_cpu(sb->raid_disks)+__le32_to_cpu(sb->delta_disks));
+               }
+               if (__le32_to_cpu(sb->new_level) != __le32_to_cpu(sb->level)) {
+                       c = map_num(pers, __le32_to_cpu(sb->new_level));
+                       printf("      New Level : %s\n", c?c:"-unknown-");
+               }
+               if (__le32_to_cpu(sb->new_layout) != __le32_to_cpu(sb->layout)) {
+                       if (__le32_to_cpu(sb->level) == 5) {
+                               c = map_num(r5layout, __le32_to_cpu(sb->new_layout));
+                               printf("     New Layout : %s\n", c?c:"-unknown-");
+                       }
+                       if (__le32_to_cpu(sb->level) == 10) {
+                               printf("     New Layout : near=%d, %s=%d\n",
+                                      __le32_to_cpu(sb->new_layout)&255,
+                                      (__le32_to_cpu(sb->new_layout)&0x10000)?"offset":"far",
+                                      (__le32_to_cpu(sb->new_layout)>>8)&255);
+                       }
+               }
+               if (__le32_to_cpu(sb->new_chunk) != __le32_to_cpu(sb->chunksize))
+                       printf("  New Chunksize : %dK\n", __le32_to_cpu(sb->new_chunk)/2);
+               printf("\n");
+       }
        if (sb->devflags) {
                printf("      Flags :");
                if (sb->devflags & WriteMostly1)
@@ -194,8 +251,10 @@ static void examine_super1(void *sbv)
        }
        if (__le32_to_cpu(sb->level) == 10) {
                int lo = __le32_to_cpu(sb->layout);
-               printf("         Layout : near=%d, far=%d\n",
-                      lo&255, (lo>>8)&255);
+               printf("         Layout : near=%d, %s=%d\n",
+                      lo&255,
+                      (lo&0x10000)?"offset":"far",
+                      (lo>>8)&255);
        }
        switch(__le32_to_cpu(sb->level)) {
        case 0:
@@ -203,10 +262,10 @@ static void examine_super1(void *sbv)
        case 5:
        case 6:
        case 10:
-               printf("     Chunk Size : %dK\n", __le32_to_cpu(sb->chunksize/2));
+               printf("     Chunk Size : %dK\n", __le32_to_cpu(sb->chunksize)/2);
                break;
        case -1:
-               printf("       Rounding : %dK\n", __le32_to_cpu(sb->chunksize/2));
+               printf("       Rounding : %dK\n", __le32_to_cpu(sb->chunksize)/2);
                break;
        default: break;
        }
@@ -297,7 +356,7 @@ static void uuid_from_super1(int uuid[4], void * sbv)
                cuuid[i] = super->set_uuid[i];
 }
 
-static void getinfo_super1(struct mdinfo *info, mddev_ident_t ident, void *sbv)
+static void getinfo_super1(struct mdinfo *info, void *sbv)
 {
        struct mdp_superblock_1 *sb = sbv;
        int working = 0;
@@ -312,6 +371,11 @@ static void getinfo_super1(struct mdinfo *info, mddev_ident_t ident, void *sbv)
        info->array.layout = __le32_to_cpu(sb->layout);
        info->array.md_minor = -1;
        info->array.ctime = __le64_to_cpu(sb->ctime);
+       info->array.utime = __le64_to_cpu(sb->utime);
+       info->array.chunk_size = __le32_to_cpu(sb->chunksize)*512;
+
+       info->data_offset = __le64_to_cpu(sb->data_offset);
+       info->component_size = __le64_to_cpu(sb->size);
 
        info->disk.major = 0;
        info->disk.minor = 0;
@@ -338,8 +402,18 @@ static void getinfo_super1(struct mdinfo *info, mddev_ident_t ident, void *sbv)
 
        memcpy(info->uuid, sb->set_uuid, 16);
 
-       strncpy(ident->name, sb->set_name, 32);
-       ident->name[32] = 0;
+       strncpy(info->name, sb->set_name, 32);
+       info->name[32] = 0;
+
+       if (sb->feature_map & __le32_to_cpu(MD_FEATURE_RESHAPE_ACTIVE)) {
+               info->reshape_active = 1;
+               info->reshape_progress = __le64_to_cpu(sb->reshape_position);
+               info->new_level = __le32_to_cpu(sb->new_level);
+               info->delta_disks = __le32_to_cpu(sb->delta_disks);
+               info->new_layout = __le32_to_cpu(sb->new_layout);
+               info->new_chunk = __le32_to_cpu(sb->new_chunk)<<9;
+       } else
+               info->reshape_active = 0;
 
        for (i=0; i< __le32_to_cpu(sb->max_dev); i++) {
                role = __le16_to_cpu(sb->dev_roles[i]);
@@ -352,14 +426,21 @@ static void getinfo_super1(struct mdinfo *info, mddev_ident_t ident, void *sbv)
 
 static int update_super1(struct mdinfo *info, void *sbv, char *update, char *devname, int verbose)
 {
+       /* NOTE: for 'assemble' and 'force' we need to return non-zero if any change was made.
+        * For others, the return value is ignored.
+        */
        int rv = 0;
        struct mdp_superblock_1 *sb = sbv;
 
        if (strcmp(update, "force")==0) {
+               if (sb->events != __cpu_to_le64(info->events))
+                       rv = 1;
                sb->events = __cpu_to_le64(info->events);
                switch(__le32_to_cpu(sb->level)) {
                case 5: case 4: case 6:
                        /* need to force clean */
+                       if (sb->resync_offset != ~0ULL)
+                               rv = 1;
                        sb->resync_offset = ~0ULL;
                }
        }
@@ -395,8 +476,16 @@ static int update_super1(struct mdinfo *info, void *sbv, char *update, char *dev
                /* make sure resync happens */
                sb->resync_offset = ~0ULL;
        }
-       if (strcmp(update, "uuid") == 0)
-               memcmp(sb->set_uuid, info->uuid, 16);
+       if (strcmp(update, "uuid") == 0) {
+               memcpy(sb->set_uuid, info->uuid, 16);
+               if (__le32_to_cpu(sb->feature_map)&MD_FEATURE_BITMAP_OFFSET) {
+                       struct bitmap_super_s *bm;
+                       bm = (struct bitmap_super_s*)(sbv+1024);
+                       memcpy(bm->uuid, info->uuid, 16);
+               }
+       }
+       if (strcmp(update, "_reshape_progress")==0)
+               sb->reshape_position = __cpu_to_le64(info->reshape_progress);
 
        sb->sb_csum = calc_sb_1_csum(sb);
        return rv;
@@ -409,7 +498,7 @@ static __u64 event_super1(void *sbv)
        return __le64_to_cpu(sb->events);
 }
 
-static int init_super1(struct supertype *st, void **sbp, mdu_array_info_t *info, char *name)
+static int init_super1(struct supertype *st, void **sbp, mdu_array_info_t *info, unsigned long long size, char *name)
 {
        struct mdp_superblock_1 *sb = malloc(1024 + sizeof(bitmap_super_t));
        int spares;
@@ -448,7 +537,7 @@ static int init_super1(struct supertype *st, void **sbp, mdu_array_info_t *info,
        sb->ctime = __cpu_to_le64((unsigned long long)time(0));
        sb->level = __cpu_to_le32(info->level);
        sb->layout = __cpu_to_le32(info->layout);
-       sb->size = __cpu_to_le64(info->size*2ULL);
+       sb->size = __cpu_to_le64(size*2ULL);
        sb->chunksize = __cpu_to_le32(info->chunk_size>>9);
        sb->raid_disks = __cpu_to_le32(info->raid_disks);
 
@@ -486,18 +575,28 @@ static void add_to_super1(void *sbv, mdu_disk_info_t *dk)
                *rp = 0xfffe;
 }
 
+static void locate_bitmap1(struct supertype *st, int fd, void *sbv);
+
 static int store_super1(struct supertype *st, int fd, void *sbv)
 {
        struct mdp_superblock_1 *sb = sbv;
        unsigned long long sb_offset;
        int sbsize;
-       long size;
-
-       if (ioctl(fd, BLKGETSIZE, &size))
-               return 1;
+       unsigned long size;
+       unsigned long long dsize;
 
+#ifdef BLKGETSIZE64
+       if (ioctl(fd, BLKGETSIZE64, &dsize) != 0)
+#endif
+       {
+               if (ioctl(fd, BLKGETSIZE, &size))
+                       return 1;
+               else
+                       dsize = (unsigned long long)size;
+       } else
+               dsize >>= 9;
 
-       if (size < 24)
+       if (dsize < 24)
                return 2;
 
        /*
@@ -510,7 +609,7 @@ static int store_super1(struct supertype *st, int fd, void *sbv)
         */
        switch(st->minor_version) {
        case 0:
-               sb_offset = size;
+               sb_offset = dsize;
                sb_offset -= 8*2;
                sb_offset &= ~(4*2-1);
                break;
@@ -541,6 +640,14 @@ static int store_super1(struct supertype *st, int fd, void *sbv)
        if (write(fd, sb, sbsize) != sbsize)
                return 4;
 
+       if (sb->feature_map & __cpu_to_le32(MD_FEATURE_BITMAP_OFFSET)) {
+               struct bitmap_super_s *bm = (struct bitmap_super_s*)
+                       ((char*)sb)+1024;
+               if (__le32_to_cpu(bm->magic) == BITMAP_MAGIC) {
+                       locate_bitmap1(st, fd, sbv);
+                       write(fd, bm, sizeof(*bm));
+               }
+       }
        fsync(fd);
        return 0;
 }
@@ -556,7 +663,8 @@ static int write_init_super1(struct supertype *st, void *sbv,
        int rfd;
        int rv;
 
-       long size;
+       unsigned long size, space;
+       unsigned long long dsize, array_size;
        long long sb_offset;
 
 
@@ -592,12 +700,18 @@ static int write_init_super1(struct supertype *st, void *sbv,
                free(refsb);
        }
 
-       if (ioctl(fd, BLKGETSIZE, &size)) {
-               close(fd);
-               return 1;
-       }
+#ifdef BLKGETSIZE64
+       if (ioctl(fd, BLKGETSIZE64, &dsize) != 0)
+#endif
+       {
+               if (ioctl(fd, BLKGETSIZE, &size))
+                       return 1;
+               else
+                       dsize = size;
+       } else
+               dsize >>= 9;
 
-       if (size < 24) {
+       if (dsize < 24) {
                close(fd);
                return 2;
        }
@@ -610,26 +724,40 @@ static int write_init_super1(struct supertype *st, void *sbv,
         * 0: At least 8K, but less than 12K, from end of device
         * 1: At start of device
         * 2: 4K from start of device.
+        * Depending on the array size, we might leave extra space
+        * for a bitmap.
         */
+       array_size = __le64_to_cpu(sb->size);
        switch(st->minor_version) {
        case 0:
-               sb_offset = size;
+               sb_offset = dsize;
                sb_offset -= 8*2;
                sb_offset &= ~(4*2-1);
                sb->super_offset = __cpu_to_le64(sb_offset);
                sb->data_offset = __cpu_to_le64(0);
-               sb->data_size = __cpu_to_le64(sb_offset);
+               if (sb_offset-64*2 >= array_size && array_size > 8*1024*1024*2)
+                       sb->data_size = __cpu_to_le64(sb_offset-64*2);
+               else
+                       sb->data_size = __cpu_to_le64(sb_offset);
                break;
        case 1:
                sb->super_offset = __cpu_to_le64(0);
-               sb->data_offset = __cpu_to_le64(4*2); /* leave 4k for super and bitmap */
-               sb->data_size = __cpu_to_le64(size - 4*2);
+               if (dsize - 64*2 >= array_size && array_size > 8*1024*1024*2)
+                       space = 64*2;
+               else
+                       space = 4*2;
+               sb->data_offset = __cpu_to_le64(space); /* leave space for super and bitmap */
+               sb->data_size = __cpu_to_le64(dsize - space);
                break;
        case 2:
                sb_offset = 4*2;
+               if (dsize - 4*2 - 64*2 >= array_size && array_size > 8*1024*1024*2)
+                       space = 64*2;
+               else
+                       space = 4*2;
                sb->super_offset = __cpu_to_le64(sb_offset);
-               sb->data_offset = __cpu_to_le64(sb_offset+4*2);
-               sb->data_size = __cpu_to_le64(size - 4*2 - 4*2);
+               sb->data_offset = __cpu_to_le64(sb_offset+space);
+               sb->data_size = __cpu_to_le64(dsize - 4*2 - space);
                break;
        default:
                return -EINVAL;
@@ -665,8 +793,8 @@ static int compare_super1(void **firstp, void *secondv)
                return 1;
 
        if (!first) {
-               first = malloc(1024);
-               memcpy(first, second, 1024);
+               first = malloc(1024+sizeof(bitmap_super_t));
+               memcpy(first, second, 1024+sizeof(bitmap_super_t));
                *firstp = first;
                return 0;
        }
@@ -686,9 +814,11 @@ static int compare_super1(void **firstp, void *secondv)
 static int load_super1(struct supertype *st, int fd, void **sbp, char *devname)
 {
        unsigned long size;
+       unsigned long long dsize;
        unsigned long long sb_offset;
        struct mdp_superblock_1 *super;
-
+       int uuid[4];
+       struct bitmap_super_s *bsb;
 
 
        if (st->ss == NULL) {
@@ -723,31 +853,38 @@ static int load_super1(struct supertype *st, int fd, void **sbp, char *devname)
                st->ss = NULL;
                return 2;
        }
-       if (ioctl(fd, BLKGETSIZE, &size)) {
-               if (devname)
-                       fprintf(stderr, Name ": cannot find device size for %s: %s\n",
-                               devname, strerror(errno));
-               return 1;
-       }
+#ifdef BLKGETSIZE64
+       if (ioctl(fd, BLKGETSIZE64, &dsize) != 0)
+#endif
+       {
+               if (ioctl(fd, BLKGETSIZE, &size)) {
+                       if (devname)
+                               fprintf(stderr, Name ": cannot find device size for %s: %s\n",
+                                       devname, strerror(errno));
+                       return 1;
+               }
+               dsize = size;
+       } else
+               dsize >>= 9;
 
-       if (size < 24) {
+       if (dsize < 24) {
                if (devname)
-                       fprintf(stderr, Name ": %s is too small for md: size is %lu sectors.\n",
-                               devname, size);
+                       fprintf(stderr, Name ": %s is too small for md: size is %llu sectors.\n",
+                               devname, dsize);
                return 1;
        }
 
        /*
         * Calculate the position of the superblock.
         * It is always aligned to a 4K boundary and
-        * depeding on minor_version, it can be:
+        * depending on minor_version, it can be:
         * 0: At least 8K, but less than 12K, from end of device
         * 1: At start of device
         * 2: 4K from start of device.
         */
        switch(st->minor_version) {
        case 0:
-               sb_offset = size;
+               sb_offset = dsize;
                sb_offset -= 8*2;
                sb_offset &= ~(4*2-1);
                break;
@@ -804,6 +941,28 @@ static int load_super1(struct supertype *st, int fd, void **sbp, char *devname)
                return 2;
        }
        *sbp = super;
+
+       /* Now check on the bitmap superblock */
+       if ((__le32_to_cpu(super->feature_map)&MD_FEATURE_BITMAP_OFFSET) == 0)
+               return 0;
+       /* Read the bitmap superblock and make sure it looks
+        * valid.  If it doesn't clear the bit.  An --assemble --force
+        * should get that written out.
+        */
+       locate_bitmap1(st, fd, super);
+       if (read(fd, ((char*)super)+1024, sizeof(struct bitmap_super_s))
+           != sizeof(struct bitmap_super_s))
+               goto no_bitmap;
+
+       uuid_from_super1(uuid, super);
+       bsb = (struct bitmap_super_s *)(((char*)super)+1024);
+       if (__le32_to_cpu(bsb->magic) != BITMAP_MAGIC ||
+           memcmp(bsb->uuid, uuid, 16) != 0)
+               goto no_bitmap;
+       return 0;
+
+ no_bitmap:
+       super->feature_map = __cpu_to_le32(__le32_to_cpu(super->feature_map) & ~1);
        return 0;
 }
 
@@ -816,7 +975,8 @@ static struct supertype *match_metadata_desc1(char *arg)
        st->ss = &super1;
        st->max_devs = 384;
        if (strcmp(arg, "1") == 0 ||
-           strcmp(arg, "1.0") == 0) {
+           strcmp(arg, "1.0") == 0 ||
+           strcmp(arg, "default/large") == 0) {
                st->minor_version = 0;
                return st;
        }
@@ -842,6 +1002,14 @@ static __u64 avail_size1(struct supertype *st, __u64 devsize)
        if (devsize < 24)
                return 0;
 
+       /* if the device is bigger than 8Gig, save 64k for bitmap usage,
+        * if biffer than 200Gig, save 128k
+        */
+       if (devsize > 200*1024*1024*2)
+               devsize -= 128*2;
+       else if (devsize > 8*1024*1024*2)
+               devsize -= 64*2;
+
        switch(st->minor_version) {
        case 0:
                /* at end */
@@ -858,7 +1026,8 @@ static __u64 avail_size1(struct supertype *st, __u64 devsize)
 
 static int
 add_internal_bitmap1(struct supertype *st, void *sbv,
-                    int chunk, int delay, int write_behind, unsigned long long size, int may_change, int major)
+                    int chunk, int delay, int write_behind, unsigned long long size,
+                    int may_change, int major)
 {
        /*
         * If not may_change, then this is a 'Grow', and the bitmap
@@ -892,11 +1061,13 @@ add_internal_bitmap1(struct supertype *st, void *sbv,
                chunk = min_chunk;
        else if (chunk < min_chunk)
                return 0; /* chunk size too small */
+       if (chunk == 0) /* rounding problem */
+               return 0;
 
        sb->bitmap_offset = __cpu_to_le32(2);
 
        sb->feature_map = __cpu_to_le32(__le32_to_cpu(sb->feature_map) | 1);
-       memset(bms, sizeof(*bms), 0);
+       memset(bms, 0, sizeof(*bms));
        bms->magic = __cpu_to_le32(BITMAP_MAGIC);
        bms->version = __cpu_to_le32(major);
        uuid_from_super1((int*)bms->uuid, sb);
@@ -909,25 +1080,27 @@ add_internal_bitmap1(struct supertype *st, void *sbv,
 }
 
 
-void locate_bitmap1(struct supertype *st, int fd, void *sbv)
+static void locate_bitmap1(struct supertype *st, int fd, void *sbv)
 {
        unsigned long long offset;
        struct mdp_superblock_1 *sb;
+       int mustfree = 0;
 
-       if (!sbv)
-               if (st->ss->load_super(st, fd, sbv, NULL))
+       if (!sbv) {
+               if (st->ss->load_super(st, fd, &sbv, NULL))
                        return; /* no error I hope... */
-
+               mustfree = 1;
+       }
        sb = sbv;
 
        offset = __le64_to_cpu(sb->super_offset);
        offset += (long) __le32_to_cpu(sb->bitmap_offset);
-       if (!sbv)
+       if (mustfree)
                free(sb);
        lseek64(fd, offset<<9, 0);
 }
 
-int write_bitmap1(struct supertype *st, int fd, void *sbv)
+static int write_bitmap1(struct supertype *st, int fd, void *sbv)
 {
        struct mdp_superblock_1 *sb = sbv;
        bitmap_super_t *bms = (bitmap_super_t*)(((char*)sb)+1024);
@@ -938,7 +1111,9 @@ int write_bitmap1(struct supertype *st, int fd, void *sbv)
 
        locate_bitmap1(st, fd, sbv);
 
-       write(fd, ((char*)sb)+1024, sizeof(bitmap_super_t));
+       if (write(fd, ((char*)sb)+1024, sizeof(bitmap_super_t)) !=
+           sizeof(bitmap_super_t))
+               return -2;
        towrite = __le64_to_cpu(bms->sync_size) / (__le32_to_cpu(bms->chunksize)>>9);
        towrite = (towrite+7) >> 3; /* bits to bytes */
        memset(buf, 0xff, sizeof(buf));