ea8f49326c106dd3a74d9234b657b435ffdd8044
[thirdparty/mdadm.git] / Grow.c
1 /*
2  * mdadm - manage Linux "md" devices aka RAID arrays.
3  *
4  * Copyright (C) 2001-2009 Neil Brown <neilb@suse.de>
5  *
6  *
7  *    This program is free software; you can redistribute it and/or modify
8  *    it under the terms of the GNU General Public License as published by
9  *    the Free Software Foundation; either version 2 of the License, or
10  *    (at your option) any later version.
11  *
12  *    This program is distributed in the hope that it will be useful,
13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *    GNU General Public License for more details.
16  *
17  *    You should have received a copy of the GNU General Public License
18  *    along with this program; if not, write to the Free Software
19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  *
21  *    Author: Neil Brown
22  *    Email: <neilb@suse.de>
23  */
24 #include        "mdadm.h"
25 #include        "dlink.h"
26 #include        <sys/mman.h>
27
28 #if ! defined(__BIG_ENDIAN) && ! defined(__LITTLE_ENDIAN)
29 #error no endian defined
30 #endif
31 #include        "md_u.h"
32 #include        "md_p.h"
33
34 #ifndef offsetof
35 #define offsetof(t,f) ((size_t)&(((t*)0)->f))
36 #endif
37
38 int Grow_Add_device(char *devname, int fd, char *newdev)
39 {
40         /* Add a device to an active array.
41          * Currently, just extend a linear array.
42          * This requires writing a new superblock on the
43          * new device, calling the kernel to add the device,
44          * and if that succeeds, update the superblock on
45          * all other devices.
46          * This means that we need to *find* all other devices.
47          */
48         struct mdinfo info;
49
50         struct stat stb;
51         int nfd, fd2;
52         int d, nd;
53         struct supertype *st = NULL;
54         char *subarray = NULL;
55
56         if (ioctl(fd, GET_ARRAY_INFO, &info.array) < 0) {
57                 fprintf(stderr, Name ": cannot get array info for %s\n", devname);
58                 return 1;
59         }
60
61         if (info.array.level != -1) {
62                 fprintf(stderr, Name ": can only add devices to linear arrays\n");
63                 return 1;
64         }
65
66         st = super_by_fd(fd, &subarray);
67         if (!st) {
68                 fprintf(stderr, Name ": cannot handle arrays with superblock version %d\n", info.array.major_version);
69                 return 1;
70         }
71
72         if (subarray) {
73                 fprintf(stderr, Name ": Cannot grow linear sub-arrays yet\n");
74                 free(subarray);
75                 free(st);
76         }
77
78         nfd = open(newdev, O_RDWR|O_EXCL|O_DIRECT);
79         if (nfd < 0) {
80                 fprintf(stderr, Name ": cannot open %s\n", newdev);
81                 free(st);
82                 return 1;
83         }
84         fstat(nfd, &stb);
85         if ((stb.st_mode & S_IFMT) != S_IFBLK) {
86                 fprintf(stderr, Name ": %s is not a block device!\n", newdev);
87                 close(nfd);
88                 free(st);
89                 return 1;
90         }
91         /* now check out all the devices and make sure we can read the superblock */
92         for (d=0 ; d < info.array.raid_disks ; d++) {
93                 mdu_disk_info_t disk;
94                 char *dv;
95
96                 st->ss->free_super(st);
97
98                 disk.number = d;
99                 if (ioctl(fd, GET_DISK_INFO, &disk) < 0) {
100                         fprintf(stderr, Name ": cannot get device detail for device %d\n",
101                                 d);
102                         close(nfd);
103                         free(st);
104                         return 1;
105                 }
106                 dv = map_dev(disk.major, disk.minor, 1);
107                 if (!dv) {
108                         fprintf(stderr, Name ": cannot find device file for device %d\n",
109                                 d);
110                         close(nfd);
111                         free(st);
112                         return 1;
113                 }
114                 fd2 = dev_open(dv, O_RDWR);
115                 if (!fd2) {
116                         fprintf(stderr, Name ": cannot open device file %s\n", dv);
117                         close(nfd);
118                         free(st);
119                         return 1;
120                 }
121
122                 if (st->ss->load_super(st, fd2, NULL)) {
123                         fprintf(stderr, Name ": cannot find super block on %s\n", dv);
124                         close(nfd);
125                         close(fd2);
126                         free(st);
127                         return 1;
128                 }
129                 close(fd2);
130         }
131         /* Ok, looks good. Lets update the superblock and write it out to
132          * newdev.
133          */
134
135         info.disk.number = d;
136         info.disk.major = major(stb.st_rdev);
137         info.disk.minor = minor(stb.st_rdev);
138         info.disk.raid_disk = d;
139         info.disk.state = (1 << MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE);
140         st->ss->update_super(st, &info, "linear-grow-new", newdev,
141                              0, 0, NULL);
142
143         if (st->ss->store_super(st, nfd)) {
144                 fprintf(stderr, Name ": Cannot store new superblock on %s\n",
145                         newdev);
146                 close(nfd);
147                 return 1;
148         }
149         close(nfd);
150
151         if (ioctl(fd, ADD_NEW_DISK, &info.disk) != 0) {
152                 fprintf(stderr, Name ": Cannot add new disk to this array\n");
153                 return 1;
154         }
155         /* Well, that seems to have worked.
156          * Now go through and update all superblocks
157          */
158
159         if (ioctl(fd, GET_ARRAY_INFO, &info.array) < 0) {
160                 fprintf(stderr, Name ": cannot get array info for %s\n", devname);
161                 return 1;
162         }
163
164         nd = d;
165         for (d=0 ; d < info.array.raid_disks ; d++) {
166                 mdu_disk_info_t disk;
167                 char *dv;
168
169                 disk.number = d;
170                 if (ioctl(fd, GET_DISK_INFO, &disk) < 0) {
171                         fprintf(stderr, Name ": cannot get device detail for device %d\n",
172                                 d);
173                         return 1;
174                 }
175                 dv = map_dev(disk.major, disk.minor, 1);
176                 if (!dv) {
177                         fprintf(stderr, Name ": cannot find device file for device %d\n",
178                                 d);
179                         return 1;
180                 }
181                 fd2 = dev_open(dv, O_RDWR);
182                 if (fd2 < 0) {
183                         fprintf(stderr, Name ": cannot open device file %s\n", dv);
184                         return 1;
185                 }
186                 if (st->ss->load_super(st, fd2, NULL)) {
187                         fprintf(stderr, Name ": cannot find super block on %s\n", dv);
188                         close(fd);
189                         return 1;
190                 }
191                 info.array.raid_disks = nd+1;
192                 info.array.nr_disks = nd+1;
193                 info.array.active_disks = nd+1;
194                 info.array.working_disks = nd+1;
195
196                 st->ss->update_super(st, &info, "linear-grow-update", dv,
197                                      0, 0, NULL);
198
199                 if (st->ss->store_super(st, fd2)) {
200                         fprintf(stderr, Name ": Cannot store new superblock on %s\n", dv);
201                         close(fd2);
202                         return 1;
203                 }
204                 close(fd2);
205         }
206
207         return 0;
208 }
209
210 int Grow_addbitmap(char *devname, int fd, char *file, int chunk, int delay, int write_behind, int force)
211 {
212         /*
213          * First check that array doesn't have a bitmap
214          * Then create the bitmap
215          * Then add it
216          *
217          * For internal bitmaps, we need to check the version,
218          * find all the active devices, and write the bitmap block
219          * to all devices
220          */
221         mdu_bitmap_file_t bmf;
222         mdu_array_info_t array;
223         struct supertype *st;
224         char *subarray = NULL;
225         int major = BITMAP_MAJOR_HI;
226         int vers = md_get_version(fd);
227         unsigned long long bitmapsize, array_size;
228
229         if (vers < 9003) {
230                 major = BITMAP_MAJOR_HOSTENDIAN;
231 #ifdef __BIG_ENDIAN
232                 fprintf(stderr, Name ": Warning - bitmaps created on this kernel are not portable\n"
233                         "  between different architectured.  Consider upgrading the Linux kernel.\n");
234 #endif
235         }
236
237         if (ioctl(fd, GET_BITMAP_FILE, &bmf) != 0) {
238                 if (errno == ENOMEM)
239                         fprintf(stderr, Name ": Memory allocation failure.\n");
240                 else
241                         fprintf(stderr, Name ": bitmaps not supported by this kernel.\n");
242                 return 1;
243         }
244         if (bmf.pathname[0]) {
245                 if (strcmp(file,"none")==0) {
246                         if (ioctl(fd, SET_BITMAP_FILE, -1)!= 0) {
247                                 fprintf(stderr, Name ": failed to remove bitmap %s\n",
248                                         bmf.pathname);
249                                 return 1;
250                         }
251                         return 0;
252                 }
253                 fprintf(stderr, Name ": %s already has a bitmap (%s)\n",
254                         devname, bmf.pathname);
255                 return 1;
256         }
257         if (ioctl(fd, GET_ARRAY_INFO, &array) != 0) {
258                 fprintf(stderr, Name ": cannot get array status for %s\n", devname);
259                 return 1;
260         }
261         if (array.state & (1<<MD_SB_BITMAP_PRESENT)) {
262                 if (strcmp(file, "none")==0) {
263                         array.state &= ~(1<<MD_SB_BITMAP_PRESENT);
264                         if (ioctl(fd, SET_ARRAY_INFO, &array)!= 0) {
265                                 fprintf(stderr, Name ": failed to remove internal bitmap.\n");
266                                 return 1;
267                         }
268                         return 0;
269                 }
270                 fprintf(stderr, Name ": Internal bitmap already present on %s\n",
271                         devname);
272                 return 1;
273         }
274
275         if (strcmp(file, "none") == 0) {
276                 fprintf(stderr, Name ": no bitmap found on %s\n", devname);
277                 return 1;
278         }
279         if (array.level <= 0) {
280                 fprintf(stderr, Name ": Bitmaps not meaningful with level %s\n",
281                         map_num(pers, array.level)?:"of this array");
282                 return 1;
283         }
284         bitmapsize = array.size;
285         bitmapsize <<= 1;
286         if (get_dev_size(fd, NULL, &array_size) &&
287             array_size > (0x7fffffffULL<<9)) {
288                 /* Array is big enough that we cannot trust array.size
289                  * try other approaches
290                  */
291                 bitmapsize = get_component_size(fd);
292         }
293         if (bitmapsize == 0) {
294                 fprintf(stderr, Name ": Cannot reliably determine size of array to create bitmap - sorry.\n");
295                 return 1;
296         }
297
298         if (array.level == 10) {
299                 int ncopies = (array.layout&255)*((array.layout>>8)&255);
300                 bitmapsize = bitmapsize * array.raid_disks / ncopies;
301         }
302
303         st = super_by_fd(fd, &subarray);
304         if (!st) {
305                 fprintf(stderr, Name ": Cannot understand version %d.%d\n",
306                         array.major_version, array.minor_version);
307                 return 1;
308         }
309         if (subarray) {
310                 fprintf(stderr, Name ": Cannot add bitmaps to sub-arrays yet\n");
311                 free(subarray);
312                 free(st);
313                 return 1;
314         }
315         if (strcmp(file, "internal") == 0) {
316                 int d;
317                 if (st->ss->add_internal_bitmap == NULL) {
318                         fprintf(stderr, Name ": Internal bitmaps not supported "
319                                 "with %s metadata\n", st->ss->name);
320                         return 1;
321                 }
322                 for (d=0; d< st->max_devs; d++) {
323                         mdu_disk_info_t disk;
324                         char *dv;
325                         disk.number = d;
326                         if (ioctl(fd, GET_DISK_INFO, &disk) < 0)
327                                 continue;
328                         if (disk.major == 0 &&
329                             disk.minor == 0)
330                                 continue;
331                         if ((disk.state & (1<<MD_DISK_SYNC))==0)
332                                 continue;
333                         dv = map_dev(disk.major, disk.minor, 1);
334                         if (dv) {
335                                 int fd2 = dev_open(dv, O_RDWR);
336                                 if (fd2 < 0)
337                                         continue;
338                                 if (st->ss->load_super(st, fd2, NULL)==0) {
339                                         if (st->ss->add_internal_bitmap(
340                                                     st,
341                                                     &chunk, delay, write_behind,
342                                                     bitmapsize, 0, major)
343                                                 )
344                                                 st->ss->write_bitmap(st, fd2);
345                                         else {
346                                                 fprintf(stderr, Name ": failed to create internal bitmap - chunksize problem.\n");
347                                                 close(fd2);
348                                                 return 1;
349                                         }
350                                 }
351                                 close(fd2);
352                         }
353                 }
354                 array.state |= (1<<MD_SB_BITMAP_PRESENT);
355                 if (ioctl(fd, SET_ARRAY_INFO, &array)!= 0) {
356                         fprintf(stderr, Name ": failed to set internal bitmap.\n");
357                         return 1;
358                 }
359         } else {
360                 int uuid[4];
361                 int bitmap_fd;
362                 int d;
363                 int max_devs = st->max_devs;
364
365                 /* try to load a superblock */
366                 for (d=0; d<max_devs; d++) {
367                         mdu_disk_info_t disk;
368                         char *dv;
369                         int fd2;
370                         disk.number = d;
371                         if (ioctl(fd, GET_DISK_INFO, &disk) < 0)
372                                 continue;
373                         if ((disk.major==0 && disk.minor==0) ||
374                             (disk.state & (1<<MD_DISK_REMOVED)))
375                                 continue;
376                         dv = map_dev(disk.major, disk.minor, 1);
377                         if (!dv) continue;
378                         fd2 = dev_open(dv, O_RDONLY);
379                         if (fd2 >= 0 &&
380                             st->ss->load_super(st, fd2, NULL) == 0) {
381                                 close(fd2);
382                                 st->ss->uuid_from_super(st, uuid);
383                                 break;
384                         }
385                         close(fd2);
386                 }
387                 if (d == max_devs) {
388                         fprintf(stderr, Name ": cannot find UUID for array!\n");
389                         return 1;
390                 }
391                 if (CreateBitmap(file, force, (char*)uuid, chunk,
392                                  delay, write_behind, bitmapsize, major)) {
393                         return 1;
394                 }
395                 bitmap_fd = open(file, O_RDWR);
396                 if (bitmap_fd < 0) {
397                         fprintf(stderr, Name ": weird: %s cannot be opened\n",
398                                 file);
399                         return 1;
400                 }
401                 if (ioctl(fd, SET_BITMAP_FILE, bitmap_fd) < 0) {
402                         fprintf(stderr, Name ": Cannot set bitmap file for %s: %s\n",
403                                 devname, strerror(errno));
404                         return 1;
405                 }
406         }
407
408         return 0;
409 }
410
411
412 /*
413  * When reshaping an array we might need to backup some data.
414  * This is written to all spares with a 'super_block' describing it.
415  * The superblock goes 4K from the end of the used space on the
416  * device.
417  * It if written after the backup is complete.
418  * It has the following structure.
419  */
420
421 static struct mdp_backup_super {
422         char    magic[16];  /* md_backup_data-1 or -2 */
423         __u8    set_uuid[16];
424         __u64   mtime;
425         /* start/sizes in 512byte sectors */
426         __u64   devstart;       /* address on backup device/file of data */
427         __u64   arraystart;
428         __u64   length;
429         __u32   sb_csum;        /* csum of preceeding bytes. */
430         __u32   pad1;
431         __u64   devstart2;      /* offset in to data of second section */
432         __u64   arraystart2;
433         __u64   length2;
434         __u32   sb_csum2;       /* csum of preceeding bytes. */
435         __u8 pad[512-68-32];
436 } __attribute__((aligned(512))) bsb, bsb2;
437
438 static __u32 bsb_csum(char *buf, int len)
439 {
440         int i;
441         int csum = 0;
442         for (i=0; i<len; i++)
443                 csum = (csum<<3) + buf[0];
444         return __cpu_to_le32(csum);
445 }
446
447 static int child_grow(int afd, struct mdinfo *sra, unsigned long blocks,
448                       int *fds, unsigned long long *offsets,
449                       int disks, int chunk, int level, int layout, int data,
450                       int dests, int *destfd, unsigned long long *destoffsets);
451 static int child_shrink(int afd, struct mdinfo *sra, unsigned long blocks,
452                         int *fds, unsigned long long *offsets,
453                         int disks, int chunk, int level, int layout, int data,
454                         int dests, int *destfd, unsigned long long *destoffsets);
455 static int child_same_size(int afd, struct mdinfo *sra, unsigned long blocks,
456                            int *fds, unsigned long long *offsets,
457                            unsigned long long start,
458                            int disks, int chunk, int level, int layout, int data,
459                            int dests, int *destfd, unsigned long long *destoffsets);
460
461 static int freeze_container(struct supertype *st)
462 {
463         int container_dev = (st->container_dev != NoMdDev
464                              ? st->container_dev : st->devnum);
465         char *container = devnum2devname(container_dev);
466
467         if (!container) {
468                 fprintf(stderr, Name
469                         ": could not determine container name, freeze aborted\n");
470                 return -2;
471         }
472
473         if (block_monitor(container, 1)) {
474                 fprintf(stderr, Name ": failed to freeze container\n");
475                 return -2;
476         }
477
478         return 1;
479 }
480
481 static void unfreeze_container(struct supertype *st)
482 {
483         int container_dev = (st->container_dev != NoMdDev
484                              ? st->container_dev : st->devnum);
485         char *container = devnum2devname(container_dev);
486
487         if (!container) {
488                 fprintf(stderr, Name
489                         ": could not determine container name, unfreeze aborted\n");
490                 return;
491         }
492
493         unblock_monitor(container, 1);
494 }
495
496 static int freeze(struct supertype *st)
497 {
498         /* Try to freeze resync/rebuild on this array/container.
499          * Return -1 if the array is busy,
500          * return -2 container cannot be frozen,
501          * return 0 if this kernel doesn't support 'frozen'
502          * return 1 if it worked.
503          */
504         if (st->ss->external)
505                 return freeze_container(st);
506         else {
507                 struct mdinfo *sra = sysfs_read(-1, st->devnum, GET_VERSION);
508                 int err;
509
510                 if (!sra)
511                         return -1;
512                 err = sysfs_freeze_array(sra);
513                 sysfs_free(sra);
514                 return err;
515         }
516 }
517
518 static void unfreeze(struct supertype *st, int frozen)
519 {
520         /* If 'frozen' is 1, unfreeze the array */
521         if (frozen <= 0)
522                 return;
523
524         if (st->ss->external)
525                 return unfreeze_container(st);
526         else {
527                 struct mdinfo *sra = sysfs_read(-1, st->devnum, GET_VERSION);
528
529                 if (sra)
530                         sysfs_set_str(sra, NULL, "sync_action", "idle");
531                 else
532                         fprintf(stderr, Name ": failed to unfreeze array\n");
533                 sysfs_free(sra);
534         }
535 }
536
537 static void wait_reshape(struct mdinfo *sra)
538 {
539         int fd = sysfs_get_fd(sra, NULL, "sync_action");
540         char action[20];
541
542         do {
543                 fd_set rfds;
544                 FD_ZERO(&rfds);
545                 FD_SET(fd, &rfds);
546                 select(fd+1, NULL, NULL, &rfds, NULL);
547                 
548                 if (sysfs_fd_get_str(fd, action, 20) < 0) {
549                         close(fd);
550                         return;
551                 }
552         } while  (strncmp(action, "reshape", 7) == 0);
553 }
554
555 static int reshape_super(struct supertype *st, long long size, int level,
556                          int layout, int chunksize, int raid_disks,
557                          char *backup_file, char *dev, int verbose)
558 {
559         /* nothing extra to check in the native case */
560         if (!st->ss->external)
561                 return 0;
562         if (!st->ss->reshape_super ||
563             !st->ss->manage_reshape) {
564                 fprintf(stderr, Name ": %s metadata does not support reshape\n",
565                         st->ss->name);
566                 return 1;
567         }
568
569         return st->ss->reshape_super(st, size, level, layout, chunksize,
570                                      raid_disks, backup_file, dev, verbose);
571 }
572
573 static void sync_metadata(struct supertype *st)
574 {
575         if (st->ss->external) {
576                 if (st->update_tail)
577                         flush_metadata_updates(st);
578                 else
579                         st->ss->sync_metadata(st);
580         }
581 }
582
583 static int subarray_set_num(char *container, struct mdinfo *sra, char *name, int n)
584 {
585         /* when dealing with external metadata subarrays we need to be
586          * prepared to handle EAGAIN.  The kernel may need to wait for
587          * mdmon to mark the array active so the kernel can handle
588          * allocations/writeback when preparing the reshape action
589          * (md_allow_write()).  We temporarily disable safe_mode_delay
590          * to close a race with the array_state going clean before the
591          * next write to raid_disks / stripe_cache_size
592          */
593         char safe[50];
594         int rc;
595
596         /* only 'raid_disks' and 'stripe_cache_size' trigger md_allow_write */
597         if (strcmp(name, "raid_disks") != 0 &&
598             strcmp(name, "stripe_cache_size") != 0)
599                 return sysfs_set_num(sra, NULL, name, n);
600
601         rc = sysfs_get_str(sra, NULL, "safe_mode_delay", safe, sizeof(safe));
602         if (rc <= 0)
603                 return -1;
604         sysfs_set_num(sra, NULL, "safe_mode_delay", 0);
605         rc = sysfs_set_num(sra, NULL, name, n);
606         if (rc < 0 && errno == EAGAIN) {
607                 ping_monitor(container);
608                 /* if we get EAGAIN here then the monitor is not active
609                  * so stop trying
610                  */
611                 rc = sysfs_set_num(sra, NULL, name, n);
612         }
613         sysfs_set_str(sra, NULL, "safe_mode_delay", safe);
614         return rc;
615 }
616
617 static int reshape_container_raid_disks(char *container, int raid_disks)
618 {
619         /* for each subarray switch to a raid level that can
620          * support the reshape, and set raid disks
621          */
622         struct mdstat_ent *ent, *e;
623         int changed = 0, rv = 0, err = 0;
624
625         ent = mdstat_read(1, 0);
626         if (!ent) {
627                 fprintf(stderr, Name ": unable to read /proc/mdstat\n");
628                 return -1;
629         }
630
631         changed = 0;
632         for (e = ent; e; e = e->next) {
633                 struct mdinfo *sub;
634                 unsigned int cache;
635                 int level, takeover_delta = 0;
636
637                 if (!is_container_member(e, container))
638                         continue;
639
640                 level = map_name(pers, e->level);
641                 if (level == 0) {
642                         sub = sysfs_read(-1, e->devnum, GET_VERSION);
643                         if (!sub)
644                                 break;
645                         /* metadata records 'orig_level' */
646                         rv = sysfs_set_num(sub, NULL, "level", 4);
647                         if (rv < 0) {
648                                 err = errno;
649                                 break;
650                         }
651                         /* we want spares to be used for capacity
652                          * expansion, not rebuild
653                          */
654                         takeover_delta = 1;
655
656                         sysfs_free(sub);
657                         level = 4;
658                 }
659
660                 sub = NULL;
661                 switch (level) {
662                 default:
663                         rv = -1;
664                         break;
665                 case 4:
666                 case 5:
667                 case 6:
668                         sub = sysfs_read(-1, e->devnum, GET_CHUNK|GET_CACHE);
669                         if (!sub)
670                                 break;
671                         cache = (sub->array.chunk_size / 4096) * 4;
672                         if (cache > sub->cache_size)
673                                 rv = subarray_set_num(container, sub,
674                                                       "stripe_cache_size", cache);
675                         if (rv) {
676                                 err = errno;
677                                 break;
678                         }
679                         /* fall through */
680                 case 1:
681                         if (!sub)
682                                 sub = sysfs_read(-1, e->devnum, GET_VERSION);
683                         if (!sub)
684                                 break;
685
686                         rv = subarray_set_num(container, sub, "raid_disks",
687                                               raid_disks + takeover_delta);
688                         if (rv)
689                                 err = errno;
690                         else
691                                 changed++;
692                         break;
693                 }
694                 sysfs_free(sub);
695                 if (rv)
696                         break;
697         }
698         free_mdstat(ent);
699         if (rv) {
700                 fprintf(stderr, Name
701                         ": failed to initiate container reshape%s%s\n",
702                         err ? ": " : "", err ? strerror(err) : "");
703                 return rv;
704         }
705
706         return changed;
707 }
708
709 static void revert_container_raid_disks(struct supertype *st, int fd, char *container)
710 {
711         /* we failed to prepare all subarrays in the container for
712          * reshape, so cancel the changes and restore the nominal raid
713          * level
714          */
715         struct mdstat_ent *ent, *e;
716
717         ent = mdstat_read(0, 0);
718         if (!ent) {
719                 fprintf(stderr, Name
720                         ": failed to read /proc/mdstat while aborting reshape\n");
721                 return;
722         }
723
724         if (st->ss->load_container(st, fd, NULL)) {
725                 fprintf(stderr, Name
726                         ": failed read metadata while aborting reshape\n");
727                 return ;
728         }
729
730
731         for (e = ent; e; e = e->next) {
732                 int level_fixed = 0, disks_fixed = 0;
733                 struct mdinfo *sub, *prev;
734                 char *subarray;
735
736                 if (!is_container_member(e, container))
737                         continue;
738
739                 subarray = to_subarray(e, container);
740                 prev = st->ss->container_content(st, subarray);
741
742                 /* changing level might change raid_disks so we do it
743                  * first and then check if raid_disks still needs fixing
744                  */
745                 if (map_name(pers, e->level) != prev->array.level) {
746                         sub = sysfs_read(-1, e->devnum, GET_VERSION);
747                         if (sub &&
748                             !sysfs_set_num(sub, NULL, "level", prev->array.level))
749                                 level_fixed = 1;
750                         sysfs_free(sub);
751                 } else
752                         level_fixed = 1;
753
754                 sub = sysfs_read(-1, e->devnum, GET_DISKS);
755                 if (sub && sub->array.raid_disks != prev->array.raid_disks) {
756                         if (!subarray_set_num(container, sub, "raid_disks",
757                                               prev->array.raid_disks))
758                                 disks_fixed = 1;
759                 } else if (sub)
760                         disks_fixed = 1;
761                 sysfs_free(sub);
762
763                 if (!disks_fixed || !level_fixed)
764                         fprintf(stderr, Name
765                                 ": failed to restore %s to a %d-disk %s array\n",
766                                 e->dev, prev->array.raid_disks,
767                                 map_num(pers, prev->array.level));
768                 free(prev);
769         }
770         st->ss->free_super(st);
771         free_mdstat(ent);
772 }
773
774 int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
775                  long long size,
776                  int level, char *layout_str, int chunksize, int raid_disks)
777 {
778         /* Make some changes in the shape of an array.
779          * The kernel must support the change.
780          *
781          * There are three different changes.  Each can trigger
782          * a resync or recovery so we freeze that until we have
783          * requested everything (if kernel supports freezing - 2.6.30).
784          * The steps are:
785          *  - change size (i.e. component_size)
786          *  - change level
787          *  - change layout/chunksize/ndisks
788          *
789          * The last can require a reshape.  It is different on different
790          * levels so we need to check the level before actioning it.
791          * Some times the level change needs to be requested after the
792          * reshape (e.g. raid6->raid5, raid5->raid0)
793          *
794          */
795         struct mdu_array_info_s array, orig;
796         char *c;
797         int rv = 0;
798         struct supertype *st;
799         char *subarray = NULL;
800
801         int nchunk, ochunk;
802         int nlayout, olayout;
803         int ndisks, odisks;
804         unsigned int ndata, odata;
805         int orig_level = UnSet;
806         char alt_layout[40];
807         int *fdlist;
808         unsigned long long *offsets;
809         int d, i;
810         int nrdisks;
811         int err;
812         int frozen;
813         unsigned long a,b, blocks, stripes;
814         unsigned long cache;
815         unsigned long long array_size;
816         int changed = 0;
817         char *container = NULL;
818         int cfd = -1;
819         int done;
820
821         struct mdinfo *sra;
822         struct mdinfo *sd;
823
824         if (ioctl(fd, GET_ARRAY_INFO, &array) < 0) {
825                 fprintf(stderr, Name ": %s is not an active md array - aborting\n",
826                         devname);
827                 return 1;
828         }
829
830         if (size >= 0 &&
831             (chunksize || level!= UnSet || layout_str || raid_disks)) {
832                 fprintf(stderr, Name ": cannot change component size at the same time "
833                         "as other changes.\n"
834                         "   Change size first, then check data is intact before "
835                         "making other changes.\n");
836                 return 1;
837         }
838
839         if (raid_disks && raid_disks < array.raid_disks && array.level > 1 &&
840             get_linux_version() < 2006032 &&
841             !check_env("MDADM_FORCE_FEWER")) {
842                 fprintf(stderr, Name ": reducing the number of devices is not safe before Linux 2.6.32\n"
843                         "       Please use a newer kernel\n");
844                 return 1;
845         }
846
847         st = super_by_fd(fd, &subarray);
848         if (!st) {
849                 fprintf(stderr, Name ": Unable to determine metadata format for %s\n", devname);
850                 return 1;
851         }
852
853         /* in the external case we need to check that the requested reshape is
854          * supported, and perform an initial check that the container holds the
855          * pre-requisite spare devices (mdmon owns final validation)
856          */
857         if (st->ss->external) {
858                 int container_dev;
859                 int rv;
860
861                 if (subarray) {
862                         container_dev = st->container_dev;
863                         cfd = open_dev_excl(st->container_dev);
864                 } else if (size >= 0 || layout_str != NULL || chunksize != 0 ||
865                            level != UnSet) {
866                         fprintf(stderr,
867                                 Name ": %s is a container, only 'raid-devices' can be changed\n",
868                                 devname);
869                         return 1;
870                 } else {
871                         container_dev = st->devnum;
872                         close(fd);
873                         cfd = open_dev_excl(st->devnum);
874                         fd = cfd;
875                 }
876                 if (cfd < 0) {
877                         fprintf(stderr, Name ": Unable to open container for %s\n",
878                                 devname);
879                         free(subarray);
880                         return 1;
881                 }
882
883                 container = devnum2devname(st->devnum);
884                 if (!container) {
885                         fprintf(stderr, Name ": Could not determine container name\n");
886                         free(subarray);
887                         return 1;
888                 }
889
890                 if (subarray)
891                         rv = st->ss->load_container(st, cfd, NULL);
892                 else
893                         rv = st->ss->load_super(st, cfd, NULL);
894                 if (rv) {
895                         fprintf(stderr, Name ": Cannot read superblock for %s\n",
896                                 devname);
897                         free(subarray);
898                         return 1;
899                 }
900
901                 if (mdmon_running(container_dev))
902                         st->update_tail = &st->updates;
903         }
904
905         sra = sysfs_read(fd, 0, GET_LEVEL);
906         if (sra) {
907                 if (st->ss->external && subarray == NULL) {
908                         array.level = LEVEL_CONTAINER;
909                         sra->array.level = LEVEL_CONTAINER;
910                 }
911         } else {
912                 fprintf(stderr, Name ": failed to read sysfs parameters for %s\n",
913                         devname);
914                 return 1;
915         }
916         frozen = freeze(st);
917         if (frozen < -1) {
918                 /* freeze() already spewed the reason */
919                 return 1;
920         } else if (frozen < 0) {
921                 fprintf(stderr, Name ": %s is performing resync/recovery and cannot"
922                         " be reshaped\n", devname);
923                 return 1;
924         }
925
926         /* ========= set size =============== */
927         if (size >= 0 && (size == 0 || size != array.size)) {
928                 long long orig_size = array.size;
929
930                 if (reshape_super(st, size, UnSet, UnSet, 0, 0, NULL, devname, !quiet)) {
931                         rv = 1;
932                         goto release;
933                 }
934                 sync_metadata(st);
935                 array.size = size;
936                 if (array.size != size) {
937                         /* got truncated to 32bit, write to
938                          * component_size instead
939                          */
940                         if (sra)
941                                 rv = sysfs_set_num(sra, NULL,
942                                                    "component_size", size);
943                         else
944                                 rv = -1;
945                 } else
946                         rv = ioctl(fd, SET_ARRAY_INFO, &array);
947                 if (rv != 0) {
948                         int err = errno;
949
950                         /* restore metadata */
951                         if (reshape_super(st, orig_size, UnSet, UnSet, 0, 0,
952                                           NULL, devname, !quiet) == 0)
953                                 sync_metadata(st);
954                         fprintf(stderr, Name ": Cannot set device size for %s: %s\n",
955                                 devname, strerror(err));
956                         if (err == EBUSY && 
957                             (array.state & (1<<MD_SB_BITMAP_PRESENT)))
958                                 fprintf(stderr, "       Bitmap must be removed before size can be changed\n");
959                         rv = 1;
960                         goto release;
961                 }
962                 ioctl(fd, GET_ARRAY_INFO, &array);
963                 size = get_component_size(fd)/2;
964                 if (size == 0)
965                         size = array.size;
966                 if (!quiet)
967                         fprintf(stderr, Name ": component size of %s has been set to %lluK\n",
968                                 devname, size);
969                 changed = 1;
970         } else if (array.level != LEVEL_CONTAINER) {
971                 size = get_component_size(fd)/2;
972                 if (size == 0)
973                         size = array.size;
974         }
975
976         /* ======= set level =========== */
977         if (level != UnSet && level != array.level) {
978                 /* Trying to change the level.
979                  * We might need to change layout first and schedule a
980                  * level change for later.
981                  * Level changes that can happen immediately are:
982                  * 0->4,5,6  1->5  4->5,6  5->1,6
983                  * Level changes that need a layout change first are:
984                  * 6->5,4,0 : need a -6 layout, or parity-last
985                  * 5->4,0   : need parity-last
986                  */
987                 if ((array.level == 6 || array.level == 5) &&
988                     (level == 5 || level == 4 || level == 0)) {
989                         /* Don't change level yet, but choose intermediate
990                          * layout
991                          */
992                         if (level == 5) {
993                                 if (layout_str == NULL)
994                                         switch (array.layout) {
995                                         case ALGORITHM_LEFT_ASYMMETRIC:
996                                         case ALGORITHM_LEFT_ASYMMETRIC_6:
997                                         case ALGORITHM_ROTATING_N_RESTART:
998                                                 layout_str = "left-asymmetric-6";
999                                                 break;
1000                                         case ALGORITHM_LEFT_SYMMETRIC:
1001                                         case ALGORITHM_LEFT_SYMMETRIC_6:
1002                                         case ALGORITHM_ROTATING_N_CONTINUE:
1003                                                 layout_str = "left-symmetric-6";
1004                                                 break;
1005                                         case ALGORITHM_RIGHT_ASYMMETRIC:
1006                                         case ALGORITHM_RIGHT_ASYMMETRIC_6:
1007                                         case ALGORITHM_ROTATING_ZERO_RESTART:
1008                                                 layout_str = "right-asymmetric-6";
1009                                                 break;
1010                                         case ALGORITHM_RIGHT_SYMMETRIC:
1011                                         case ALGORITHM_RIGHT_SYMMETRIC_6:
1012                                                 layout_str = "right-symmetric-6";
1013                                                 break;
1014                                         case ALGORITHM_PARITY_0:
1015                                         case ALGORITHM_PARITY_0_6:
1016                                                 layout_str = "parity-first-6";
1017                                                 break;
1018                                         case ALGORITHM_PARITY_N:
1019                                                 layout_str = "parity-last";
1020                                                 break;
1021                                         default:
1022                                                 fprintf(stderr, Name ": %s: cannot"
1023                                                         "convert layout to RAID5 equivalent\n",
1024                                                         devname);
1025                                                 rv = 1;
1026                                                 goto release;
1027                                         }
1028                                 else {
1029                                         int l = map_name(r5layout, layout_str);
1030                                         if (l == UnSet) {
1031                                                 fprintf(stderr, Name ": %s: layout '%s' not recognised\n",
1032                                                         devname, layout_str);
1033                                                 rv = 1;
1034                                                 goto release;
1035                                         }
1036                                         if (l != ALGORITHM_PARITY_N) {
1037                                                 /* need the -6 version */
1038                                                 char *ls = map_num(r5layout, l);
1039                                                 strcat(strcpy(alt_layout, ls),
1040                                                        "-6");
1041                                                 layout_str = alt_layout;
1042                                         }
1043                                 }
1044                                 if (raid_disks)
1045                                         /* The final raid6->raid5 conversion
1046                                          * will reduce the number of disks,
1047                                          * so now we need to aim higher
1048                                          */
1049                                         raid_disks++;
1050                         } else
1051                                 layout_str = "parity-last";
1052                 } else {
1053                         /* Level change is a simple takeover.  In the external
1054                          * case we don't check with the metadata handler until
1055                          * we establish what the final layout will be.  If the
1056                          * level change is disallowed we will revert to
1057                          * orig_level without disturbing the metadata, otherwise
1058                          * we will send an update.
1059                          */
1060                         c = map_num(pers, level);
1061                         if (c == NULL) {
1062                                 rv = 1;/* not possible */
1063                                 goto release;
1064                         }
1065                         err = sysfs_set_str(sra, NULL, "level", c);
1066                         if (err) {
1067                                 err = errno;
1068                                 fprintf(stderr, Name ": %s: could not set level to %s\n",
1069                                         devname, c);
1070                                 if (err == EBUSY && 
1071                                     (array.state & (1<<MD_SB_BITMAP_PRESENT)))
1072                                         fprintf(stderr, "       Bitmap must be removed before level can be changed\n");
1073                                 rv = 1;
1074                                 goto release;
1075                         }
1076                         orig = array;
1077                         orig_level = orig.level;
1078                         ioctl(fd, GET_ARRAY_INFO, &array);
1079                         if (layout_str == NULL &&
1080                             orig.level == 5 && level == 6 &&
1081                             array.layout != orig.layout)
1082                                 layout_str = map_num(r5layout, orig.layout);
1083                         if (!quiet)
1084                                 fprintf(stderr, Name " level of %s changed to %s\n",
1085                                         devname, c);
1086                         changed = 1;
1087                 }
1088         }
1089
1090         /* ========= set shape (chunk_size / layout / ndisks)  ============== */
1091         /* Check if layout change is a no-op */
1092         switch (array.level) {
1093         case 5:
1094                 if (layout_str && array.layout == map_name(r5layout, layout_str))
1095                         layout_str = NULL;
1096                 break;
1097         case 6:
1098                 if (layout_str == NULL &&
1099                     ((chunksize && chunksize * 1024 != array.chunk_size) ||
1100                      (raid_disks && raid_disks != array.raid_disks)) &&
1101                     array.layout >= 16) {
1102                         fprintf(stderr, Name
1103                                 ": %s has a non-standard layout.  If you wish to preserve this\n"
1104                                 "      during the reshape, please specify --layout=preserve\n"
1105                                 "      If you want to change it, specify a layout or use --layout=normalise\n",
1106                                 devname);
1107                         rv = 1;
1108                         goto release;
1109                 }
1110                 if (layout_str &&
1111                     (strcmp(layout_str, "normalise") == 0 ||
1112                      strcmp(layout_str, "normalize") == 0)) {
1113                         char *hyphen;
1114                         strcpy(alt_layout, map_num(r6layout, array.layout));
1115                         hyphen = strrchr(alt_layout, '-');
1116                         if (hyphen && strcmp(hyphen, "-6") == 0) {
1117                                 *hyphen = 0;
1118                                 layout_str = alt_layout;
1119                         }
1120                 }
1121
1122                 if (layout_str && array.layout == map_name(r6layout, layout_str))
1123                         layout_str = NULL;
1124                 if (layout_str && strcmp(layout_str, "preserve") == 0)
1125                         layout_str = NULL;
1126                 break;
1127         }
1128         if (layout_str == NULL
1129             && (chunksize == 0 || chunksize*1024 == array.chunk_size)
1130             && (raid_disks == 0 || raid_disks == array.raid_disks)) {
1131                 if (reshape_super(st, -1, level, UnSet, 0, 0, NULL, devname, !quiet)) {
1132                         rv = 1;
1133                         goto release;
1134                 }
1135                 sync_metadata(st);
1136                 rv = 0;
1137                 if (level != UnSet && level != array.level) {
1138                         /* Looks like this level change doesn't need
1139                          * a reshape after all.
1140                          */
1141                         c = map_num(pers, level);
1142                         if (c) {
1143                                 rv = sysfs_set_str(sra, NULL, "level", c);
1144                                 if (rv) {
1145                                         int err = errno;
1146                                         fprintf(stderr, Name ": %s: could not set level to %s\n",
1147                                                 devname, c);
1148                                         if (err == EBUSY && 
1149                                             (array.state & (1<<MD_SB_BITMAP_PRESENT)))
1150                                                 fprintf(stderr, "       Bitmap must be removed before level can be changed\n");
1151                                         rv = 1;
1152                                 }
1153                         }
1154                 } else if (!changed && !quiet)
1155                         fprintf(stderr, Name ": %s: no change requested\n",
1156                                 devname);
1157
1158                 if (st->ss->external && !mdmon_running(st->container_dev) &&
1159                     level > 0) {
1160                         start_mdmon(st->container_dev);
1161                         ping_monitor(container);
1162                 }
1163                 goto release;
1164         }
1165
1166         c = map_num(pers, array.level);
1167         if (c == NULL) c = "-unknown-";
1168         switch (array.level) {
1169         default: /* raid0, linear, multipath cannot be reconfigured */
1170                 fprintf(stderr, Name ": %s array %s cannot be reshaped.\n",
1171                         c, devname);
1172                 /* TODO raid0 raiddisks can be reshaped via raid4 */
1173                 rv = 1;
1174                 break;
1175         case LEVEL_CONTAINER: {
1176                 int count;
1177
1178                 /* double check that we are not changing anything but raid_disks */
1179                 if (size >= 0 || layout_str != NULL || chunksize != 0 || level != UnSet) {
1180                         fprintf(stderr,
1181                                 Name ": %s is a container, only 'raid-devices' can be changed\n",
1182                                 devname);
1183                         rv = 1;
1184                         goto release;
1185                 }
1186
1187                 st->update_tail = &st->updates;
1188                 if (reshape_super(st, -1, UnSet, UnSet, 0, raid_disks,
1189                                   backup_file, devname, !quiet)) {
1190                         rv = 1;
1191                         goto release;
1192                 }
1193
1194                 count = reshape_container_raid_disks(container, raid_disks);
1195                 if (count < 0) {
1196                         revert_container_raid_disks(st, fd, container);
1197                         rv = 1;
1198                         goto release;
1199                 } else if (count == 0) {
1200                         if (!quiet)
1201                                 fprintf(stderr, Name
1202                                         ": no active subarrays to reshape\n");
1203                         goto release;
1204                 }
1205
1206                 if (!mdmon_running(st->devnum)) {
1207                         start_mdmon(st->devnum);
1208                         ping_monitor(container);
1209                 }
1210                 sync_metadata(st);
1211
1212                 /* give mdmon a chance to allocate spares */
1213                 ping_manager(container);
1214
1215                 /* manage_reshape takes care of releasing the array(s) */
1216                 st->ss->manage_reshape(st, backup_file);
1217                 frozen = 0;
1218                 goto release;
1219         }
1220         case LEVEL_FAULTY: /* only 'layout' change is permitted */
1221
1222                 if (chunksize  || raid_disks) {
1223                         fprintf(stderr, Name ": %s: Cannot change chunksize or disks of a 'faulty' array\n",
1224                                 devname);
1225                         rv = 1;
1226                         break;
1227                 }
1228                 if (layout_str == NULL)
1229                         break; /* nothing to do.... */
1230
1231                 array.layout = parse_layout_faulty(layout_str);
1232                 if (array.layout < 0) {
1233                         fprintf(stderr, Name ": %s: layout %s not understood for 'faulty' array\n",
1234                                 devname, layout_str);
1235                         rv = 1;
1236                         break;
1237                 }
1238                 if (ioctl(fd, SET_ARRAY_INFO, &array) != 0) {
1239                         fprintf(stderr, Name ": Cannot set layout for %s: %s\n",
1240                                 devname, strerror(errno));
1241                         rv = 1;
1242                 } else if (!quiet)
1243                         printf("layout for %s set to %d\n", devname, array.layout);
1244                 break;
1245
1246         case 1: /* only raid_disks can each be changed. */
1247
1248                 if (chunksize || layout_str != NULL) {
1249                         fprintf(stderr, Name ": %s: Cannot change chunk size or layout for a RAID1 array.\n",
1250                                 devname);
1251                         rv = 1;
1252                         break;
1253                 }
1254                 if (raid_disks > 0) {
1255                         if (reshape_super(st, -1, UnSet, UnSet, 0, raid_disks,
1256                                           NULL, devname, !quiet)) {
1257                                 rv = 1;
1258                                 goto release;
1259                         }
1260                         sync_metadata(st);
1261                         array.raid_disks = raid_disks;
1262                         if (ioctl(fd, SET_ARRAY_INFO, &array) != 0) {
1263                                 fprintf(stderr, Name ": Cannot set raid-devices for %s: %s\n",
1264                                         devname, strerror(errno));
1265                                 rv = 1;
1266                         }
1267                 }
1268                 break;
1269
1270         case 4:
1271         case 5:
1272         case 6:
1273
1274                 /*
1275                  * layout/chunksize/raid_disks can be changed
1276                  * though the kernel may not support it all.
1277                  */
1278                 if (subarray) {
1279                         fprintf(stderr, Name ": Cannot reshape subarrays yet\n");
1280                         break;
1281                 }
1282
1283                 /*
1284                  * There are three possibilities.
1285                  * 1/ The array will shrink.
1286                  *    We need to ensure the reshape will pause before reaching
1287                  *    the 'critical section'.  We also need to fork and wait for
1288                  *    that to happen.  When it does we 
1289                  *       suspend/backup/complete/unfreeze
1290                  *
1291                  * 2/ The array will not change size.
1292                  *    This requires that we keep a backup of a sliding window
1293                  *    so that we can restore data after a crash.  So we need
1294                  *    to fork and monitor progress.
1295                  *
1296                  * 3/ The array will grow. This is relatively easy.
1297                  *    However the kernel's restripe routines will cheerfully
1298                  *    overwrite some early data before it is safe.  So we
1299                  *    need to make a backup of the early parts of the array
1300                  *    and be ready to restore it if rebuild aborts very early.
1301                  *
1302                  *    We backup data by writing it to one spare, or to a
1303                  *    file which was given on command line.
1304                  *
1305                  *    [FOLLOWING IS OLD AND PARTLY WRONG]
1306                  *    So: we enumerate the devices in the array and
1307                  *    make sure we can open all of them.
1308                  *    Then we freeze the early part of the array and
1309                  *    backup to the various spares.
1310                  *    Then we request changes and start the reshape.
1311                  *    Monitor progress until it has passed the danger zone.
1312                  *    and finally invalidate the copied data and unfreeze the
1313                  *    start of the array.
1314                  *
1315                  * In each case, we first make sure that storage is available
1316                  * for the required backup.
1317                  * Then we:
1318                  *   -  request the shape change.
1319                  *   -  for to handle backup etc.
1320                  */
1321                 nchunk = ochunk = array.chunk_size;
1322                 nlayout = olayout = array.layout;
1323                 ndisks = odisks = array.raid_disks;
1324
1325                 if (chunksize) {
1326                         nchunk = chunksize * 1024;
1327                         if (size % chunksize) {
1328                                 fprintf(stderr, Name ": component size %lluK is not"
1329                                         " a multiple of chunksize %dK\n",
1330                                         size, chunksize);
1331                                 break;
1332                         }
1333                 }
1334                 if (layout_str != NULL)
1335                         switch(array.level) {
1336                         case 4: /* ignore layout */
1337                                 break;
1338                         case 5:
1339                                 nlayout = map_name(r5layout, layout_str);
1340                                 if (nlayout == UnSet) {
1341                                         fprintf(stderr, Name ": layout %s not understood for raid5.\n",
1342                                                 layout_str);
1343                                         rv = 1;
1344                                         goto release;
1345                                 }
1346                                 break;
1347
1348                         case 6:
1349                                 nlayout = map_name(r6layout, layout_str);
1350                                 if (nlayout == UnSet) {
1351                                         fprintf(stderr, Name ": layout %s not understood for raid6.\n",
1352                                                 layout_str);
1353                                         rv = 1;
1354                                         goto release;
1355                                 }
1356                                 break;
1357                         }
1358                 if (raid_disks) ndisks = raid_disks;
1359
1360                 odata = odisks-1;
1361                 ndata = ndisks-1;
1362                 if (array.level == 6) {
1363                         odata--; /* number of data disks */
1364                         ndata--;
1365                 }
1366
1367                 if (odata == ndata &&
1368                     get_linux_version() < 2006032) {
1369                         fprintf(stderr, Name ": in-place reshape is not safe before 2.6.32, sorry.\n");
1370                         break;
1371                 }
1372
1373                 /* Check that we can hold all the data */
1374                 get_dev_size(fd, NULL, &array_size);
1375                 if (ndata * (unsigned long long)size < (array_size/1024)) {
1376                         fprintf(stderr, Name ": this change will reduce the size of the array.\n"
1377                                 "       use --grow --array-size first to truncate array.\n"
1378                                 "       e.g. mdadm --grow %s --array-size %llu\n",
1379                                 devname, ndata * size);
1380                         rv = 1;
1381                         break;
1382                 }
1383
1384                 /* So how much do we need to backup.
1385                  * We need an amount of data which is both a whole number of
1386                  * old stripes and a whole number of new stripes.
1387                  * So LCM for (chunksize*datadisks).
1388                  */
1389                 a = (ochunk/512) * odata;
1390                 b = (nchunk/512) * ndata;
1391                 /* Find GCD */
1392                 while (a != b) {
1393                         if (a < b)
1394                                 b -= a;
1395                         if (b < a)
1396                                 a -= b;
1397                 }
1398                 /* LCM == product / GCD */
1399                 blocks = (ochunk/512) * (nchunk/512) * odata * ndata / a;
1400
1401                 sysfs_free(sra);
1402                 sra = sysfs_read(fd, 0,
1403                                  GET_COMPONENT|GET_DEVS|GET_OFFSET|GET_STATE|
1404                                  GET_CACHE);
1405
1406                 if (!sra) {
1407                         fprintf(stderr, Name ": %s: Cannot get array details from sysfs\n",
1408                                 devname);
1409                         rv = 1;
1410                         break;
1411                 }
1412
1413                 if (ndata == odata) {
1414                         /* Make 'blocks' bigger for better throughput, but
1415                          * not so big that we reject it below.
1416                          * Try for 16 megabytes
1417                          */
1418                         while (blocks * 32 < sra->component_size &&
1419                                blocks < 16*1024*2)
1420                                blocks *= 2;
1421                 } else
1422                         fprintf(stderr, Name ": Need to backup %luK of critical "
1423                                 "section..\n", blocks/2);
1424
1425                 if (blocks >= sra->component_size/2) {
1426                         fprintf(stderr, Name ": %s: Something wrong - reshape aborted\n",
1427                                 devname);
1428                         rv = 1;
1429                         break;
1430                 }
1431                 nrdisks = array.raid_disks + sra->array.spare_disks;
1432                 /* Now we need to open all these devices so we can read/write.
1433                  */
1434                 fdlist = malloc((1+nrdisks) * sizeof(int));
1435                 offsets = malloc((1+nrdisks) * sizeof(offsets[0]));
1436                 if (!fdlist || !offsets) {
1437                         fprintf(stderr, Name ": malloc failed: grow aborted\n");
1438                         rv = 1;
1439                         break;
1440                 }
1441                 for (d=0; d <= nrdisks; d++)
1442                         fdlist[d] = -1;
1443                 d = array.raid_disks;
1444                 for (sd = sra->devs; sd; sd=sd->next) {
1445                         if (sd->disk.state & (1<<MD_DISK_FAULTY))
1446                                 continue;
1447                         if (sd->disk.state & (1<<MD_DISK_SYNC)) {
1448                                 char *dn = map_dev(sd->disk.major,
1449                                                    sd->disk.minor, 1);
1450                                 fdlist[sd->disk.raid_disk]
1451                                         = dev_open(dn, O_RDONLY);
1452                                 offsets[sd->disk.raid_disk] = sd->data_offset*512;
1453                                 if (fdlist[sd->disk.raid_disk] < 0) {
1454                                         fprintf(stderr, Name ": %s: cannot open component %s\n",
1455                                                 devname, dn?dn:"-unknown-");
1456                                         rv = 1;
1457                                         goto release;
1458                                 }
1459                         } else if (backup_file == NULL) {
1460                                 /* spare */
1461                                 char *dn = map_dev(sd->disk.major,
1462                                                    sd->disk.minor, 1);
1463                                 fdlist[d] = dev_open(dn, O_RDWR);
1464                                 offsets[d] = (sd->data_offset + sra->component_size - blocks - 8)*512;
1465                                 if (fdlist[d]<0) {
1466                                         fprintf(stderr, Name ": %s: cannot open component %s\n",
1467                                                 devname, dn?dn:"-unknown");
1468                                         rv = 1;
1469                                         goto release;
1470                                 }
1471                                 d++;
1472                         }
1473                 }
1474                 if (backup_file == NULL) {
1475                         if (st->ss->external && !st->ss->manage_reshape) {
1476                                 fprintf(stderr, Name ": %s Grow operation not supported by %s metadata\n",
1477                                         devname, st->ss->name);
1478                                 rv = 1;
1479                                 break;
1480                         }
1481                         if (ndata <= odata) {
1482                                 fprintf(stderr, Name ": %s: Cannot grow - need backup-file\n",
1483                                         devname);
1484                                 rv = 1;
1485                                 break;
1486                         } else if (sra->array.spare_disks == 0) {
1487                                 fprintf(stderr, Name ": %s: Cannot grow - need a spare or "
1488                                         "backup-file to backup critical section\n",
1489                                         devname);
1490                                 rv = 1;
1491                                 break;
1492                         }
1493                         if (d == array.raid_disks) {
1494                                 fprintf(stderr, Name ": %s: No spare device for backup\n",
1495                                         devname);
1496                                 rv = 1;
1497                                 break;
1498                         }
1499                 } else {
1500                         /* need to check backup file is large enough */
1501                         char buf[512];
1502                         fdlist[d] = open(backup_file, O_RDWR|O_CREAT|O_EXCL,
1503                                      S_IRUSR | S_IWUSR);
1504                         offsets[d] = 8 * 512;
1505                         if (fdlist[d] < 0) {
1506                                 fprintf(stderr, Name ": %s: cannot create backup file %s: %s\n",
1507                                         devname, backup_file, strerror(errno));
1508                                 rv = 1;
1509                                 break;
1510                         }
1511                         memset(buf, 0, 512);
1512                         for (i=0; i < (signed)blocks + 1 ; i++) {
1513                                 if (write(fdlist[d], buf, 512) != 512) {
1514                                         fprintf(stderr, Name ": %s: cannot create backup file %s: %s\n",
1515                                                 devname, backup_file, strerror(errno));
1516                                         rv = 1;
1517                                         break;
1518                                 }
1519                         }
1520                         if (fsync(fdlist[d]) != 0) {
1521                                 fprintf(stderr, Name ": %s: cannot create backup file %s: %s\n",
1522                                         devname, backup_file, strerror(errno));
1523                                 rv = 1;
1524                                 break;
1525                         }
1526                         d++;
1527                 }
1528
1529                 /* check that the operation is supported by the metadata */
1530                 if (reshape_super(st, -1, level, nlayout, nchunk, ndisks,
1531                                   backup_file, devname, !quiet)) {
1532                         rv = 1;
1533                         break;
1534                 }
1535
1536                 /* lastly, check that the internal stripe cache is
1537                  * large enough, or it won't work.
1538                  */
1539                 
1540                 cache = (nchunk < ochunk) ? ochunk : nchunk;
1541                 cache = cache * 4 / 4096;
1542                 if (cache < blocks / 8 / odisks + 16)
1543                         /* Make it big enough to hold 'blocks' */
1544                         cache = blocks / 8 / odisks + 16;
1545                 if (sra->cache_size < cache)
1546                         sysfs_set_num(sra, NULL, "stripe_cache_size",
1547                                       cache+1);
1548                 /* Right, everything seems fine. Let's kick things off.
1549                  * If only changing raid_disks, use ioctl, else use
1550                  * sysfs.
1551                  */
1552                 sync_metadata(st);
1553                 if (ochunk == nchunk && olayout == nlayout) {
1554                         array.raid_disks = ndisks;
1555                         if (ioctl(fd, SET_ARRAY_INFO, &array) != 0) {
1556                                 int err = errno;
1557                                 rv = 1;
1558                                 fprintf(stderr, Name ": Cannot set device shape for %s: %s\n",
1559                                         devname, strerror(errno));
1560                                 if (ndisks < odisks &&
1561                                     get_linux_version() < 2006030)
1562                                         fprintf(stderr, Name ": linux 2.6.30 or later required\n");
1563                                 if (err == EBUSY && 
1564                                     (array.state & (1<<MD_SB_BITMAP_PRESENT)))
1565                                         fprintf(stderr, "       Bitmap must be removed before shape can be changed\n");
1566
1567                                 break;
1568                         }
1569                 } else {
1570                         /* set them all just in case some old 'new_*' value
1571                          * persists from some earlier problem
1572                          */
1573                         int err = err; /* only used if rv==1, and always set if
1574                                         * rv==1, so initialisation not needed,
1575                                         * despite gcc warning
1576                                         */
1577                         if (sysfs_set_num(sra, NULL, "chunk_size", nchunk) < 0)
1578                                 rv = 1, err = errno;
1579                         if (!rv && sysfs_set_num(sra, NULL, "layout", nlayout) < 0)
1580                                 rv = 1, err = errno;
1581                         if (!rv && sysfs_set_num(sra, NULL, "raid_disks", ndisks) < 0)
1582                                 rv = 1, err = errno;
1583                         if (rv) {
1584                                 fprintf(stderr, Name ": Cannot set device shape for %s\n",
1585                                         devname);
1586                                 if (get_linux_version() < 2006030)
1587                                         fprintf(stderr, Name ": linux 2.6.30 or later required\n");
1588                                 if (err == EBUSY && 
1589                                     (array.state & (1<<MD_SB_BITMAP_PRESENT)))
1590                                         fprintf(stderr, "       Bitmap must be removed before shape can be changed\n");
1591                                 break;
1592                         }
1593                 }
1594
1595                 if (ndisks == 2 && odisks == 2) {
1596                         /* No reshape is needed in this trivial case */
1597                         rv = 0;
1598                         break;
1599                 }
1600
1601                 if (st->ss->external) {
1602                         /* metadata handler takes it from here */
1603                         ping_manager(container);
1604                         st->ss->manage_reshape(st, backup_file);
1605                         frozen = 0;
1606                         break;
1607                 }
1608
1609                 /* set up the backup-super-block.  This requires the
1610                  * uuid from the array.
1611                  */
1612                 /* Find a superblock */
1613                 for (sd = sra->devs; sd; sd = sd->next) {
1614                         char *dn;
1615                         int devfd;
1616                         int ok;
1617                         if (sd->disk.state & (1<<MD_DISK_FAULTY))
1618                                 continue;
1619                         dn = map_dev(sd->disk.major, sd->disk.minor, 1);
1620                         devfd = dev_open(dn, O_RDONLY);
1621                         if (devfd < 0)
1622                                 continue;
1623                         ok = st->ss->load_super(st, devfd, NULL);
1624                         close(devfd);
1625                         if (ok >= 0)
1626                                 break;
1627                 }
1628                 if (!sd) {
1629                         fprintf(stderr, Name ": %s: Cannot find a superblock\n",
1630                                 devname);
1631                         rv = 1;
1632                         break;
1633                 }
1634
1635                 memset(&bsb, 0, 512);
1636                 memcpy(bsb.magic, "md_backup_data-1", 16);
1637                 st->ss->uuid_from_super(st, (int*)&bsb.set_uuid);
1638                 bsb.mtime = __cpu_to_le64(time(0));
1639                 bsb.devstart2 = blocks;
1640                 stripes = blocks / (ochunk/512) / odata;
1641                 /* Now we just need to kick off the reshape and watch, while
1642                  * handling backups of the data...
1643                  * This is all done by a forked background process.
1644                  */
1645                 switch(fork()) {
1646                 case 0:
1647                         close(fd);
1648                         if (check_env("MDADM_GROW_VERIFY"))
1649                                 fd = open(devname, O_RDONLY | O_DIRECT);
1650                         else
1651                                 fd = -1;
1652                         mlockall(MCL_FUTURE);
1653
1654                         if (odata < ndata)
1655                                 done = child_grow(fd, sra, stripes,
1656                                                   fdlist, offsets,
1657                                                   odisks, ochunk, array.level, olayout, odata,
1658                                                   d - odisks, fdlist+odisks, offsets+odisks);
1659                         else if (odata > ndata)
1660                                 done = child_shrink(fd, sra, stripes,
1661                                                     fdlist, offsets,
1662                                                     odisks, ochunk, array.level, olayout, odata,
1663                                                     d - odisks, fdlist+odisks, offsets+odisks);
1664                         else
1665                                 done = child_same_size(fd, sra, stripes,
1666                                                        fdlist, offsets,
1667                                                        0,
1668                                                        odisks, ochunk, array.level, olayout, odata,
1669                                                        d - odisks, fdlist+odisks, offsets+odisks);
1670                         if (backup_file && done)
1671                                 unlink(backup_file);
1672                         if (level != UnSet && level != array.level) {
1673                                 /* We need to wait for the reshape to finish
1674                                  * (which will have happened unless odata < ndata)
1675                                  * and then set the level
1676                                  */
1677
1678                                 c = map_num(pers, level);
1679                                 if (c == NULL)
1680                                         exit(0);/* not possible */
1681
1682                                 if (odata < ndata)
1683                                         wait_reshape(sra);
1684                                 err = sysfs_set_str(sra, NULL, "level", c);
1685                                 if (err)
1686                                         fprintf(stderr, Name ": %s: could not set level to %s\n",
1687                                                 devname, c);
1688                         }
1689                         exit(0);
1690                 case -1:
1691                         fprintf(stderr, Name ": Cannot run child to monitor reshape: %s\n",
1692                                 strerror(errno));
1693                         rv = 1;
1694                         break;
1695                 default:
1696                         /* The child will take care of unfreezing the array */
1697                         frozen = 0;
1698                         break;
1699                 }
1700                 break;
1701
1702         }
1703
1704  release:
1705         if (rv && orig_level != UnSet && sra) {
1706                 c = map_num(pers, orig_level);
1707                 if (c && sysfs_set_str(sra, NULL, "level", c) == 0)
1708                         fprintf(stderr, Name ": aborting level change\n");
1709         }
1710         unfreeze(st, frozen);
1711         return rv;
1712 }
1713
1714 /*
1715  * We run a child process in the background which performs the following
1716  * steps:
1717  *   - wait for resync to reach a certain point
1718  *   - suspend io to the following section
1719  *   - backup that section
1720  *   - allow resync to proceed further
1721  *   - resume io
1722  *   - discard the backup.
1723  *
1724  * When are combined in slightly different ways in the three cases.
1725  * Grow:
1726  *   - suspend/backup/allow/wait/resume/discard
1727  * Shrink:
1728  *   - allow/wait/suspend/backup/allow/wait/resume/discard
1729  * same-size:
1730  *   - wait/resume/discard/suspend/backup/allow
1731  *
1732  * suspend/backup/allow always come together
1733  * wait/resume/discard do too.
1734  * For the same-size case we have two backups to improve flow.
1735  * 
1736  */
1737
1738 /* FIXME return status is never checked */
1739 static int grow_backup(struct mdinfo *sra,
1740                 unsigned long long offset, /* per device */
1741                 unsigned long stripes, /* per device */
1742                 int *sources, unsigned long long *offsets,
1743                 int disks, int chunk, int level, int layout,
1744                 int dests, int *destfd, unsigned long long *destoffsets,
1745                 int part, int *degraded,
1746                 char *buf)
1747 {
1748         /* Backup 'blocks' sectors at 'offset' on each device of the array,
1749          * to storage 'destfd' (offset 'destoffsets'), after first
1750          * suspending IO.  Then allow resync to continue
1751          * over the suspended section.
1752          * Use part 'part' of the backup-super-block.
1753          */
1754         int odata = disks;
1755         int rv = 0;
1756         int i;
1757         unsigned long long ll;
1758         int new_degraded;
1759         //printf("offset %llu\n", offset);
1760         if (level >= 4)
1761                 odata--;
1762         if (level == 6)
1763                 odata--;
1764         sysfs_set_num(sra, NULL, "suspend_hi", (offset + stripes * (chunk/512)) * odata);
1765         /* Check that array hasn't become degraded, else we might backup the wrong data */
1766         sysfs_get_ll(sra, NULL, "degraded", &ll);
1767         new_degraded = (int)ll;
1768         if (new_degraded != *degraded) {
1769                 /* check each device to ensure it is still working */
1770                 struct mdinfo *sd;
1771                 for (sd = sra->devs ; sd ; sd = sd->next) {
1772                         if (sd->disk.state & (1<<MD_DISK_FAULTY))
1773                                 continue;
1774                         if (sd->disk.state & (1<<MD_DISK_SYNC)) {
1775                                 char sbuf[20];
1776                                 if (sysfs_get_str(sra, sd, "state", sbuf, 20) < 0 ||
1777                                     strstr(sbuf, "faulty") ||
1778                                     strstr(sbuf, "in_sync") == NULL) {
1779                                         /* this device is dead */
1780                                         sd->disk.state = (1<<MD_DISK_FAULTY);
1781                                         if (sd->disk.raid_disk >= 0 &&
1782                                             sources[sd->disk.raid_disk] >= 0) {
1783                                                 close(sources[sd->disk.raid_disk]);
1784                                                 sources[sd->disk.raid_disk] = -1;
1785                                         }
1786                                 }
1787                         }
1788                 }
1789                 *degraded = new_degraded;
1790         }
1791         if (part) {
1792                 bsb.arraystart2 = __cpu_to_le64(offset * odata);
1793                 bsb.length2 = __cpu_to_le64(stripes * (chunk/512) * odata);
1794         } else {
1795                 bsb.arraystart = __cpu_to_le64(offset * odata);
1796                 bsb.length = __cpu_to_le64(stripes * (chunk/512) * odata);
1797         }
1798         if (part)
1799                 bsb.magic[15] = '2';
1800         for (i = 0; i < dests; i++)
1801                 if (part)
1802                         lseek64(destfd[i], destoffsets[i] + __le64_to_cpu(bsb.devstart2)*512, 0);
1803                 else
1804                         lseek64(destfd[i], destoffsets[i], 0);
1805
1806         rv = save_stripes(sources, offsets, 
1807                           disks, chunk, level, layout,
1808                           dests, destfd,
1809                           offset*512*odata, stripes * chunk * odata,
1810                           buf);
1811
1812         if (rv)
1813                 return rv;
1814         bsb.mtime = __cpu_to_le64(time(0));
1815         for (i = 0; i < dests; i++) {
1816                 bsb.devstart = __cpu_to_le64(destoffsets[i]/512);
1817
1818                 bsb.sb_csum = bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb));
1819                 if (memcmp(bsb.magic, "md_backup_data-2", 16) == 0)
1820                         bsb.sb_csum2 = bsb_csum((char*)&bsb,
1821                                                 ((char*)&bsb.sb_csum2)-((char*)&bsb));
1822
1823                 rv = -1;
1824                 if ((unsigned long long)lseek64(destfd[i], destoffsets[i] - 4096, 0)
1825                     != destoffsets[i] - 4096)
1826                         break;
1827                 if (write(destfd[i], &bsb, 512) != 512)
1828                         break;
1829                 if (destoffsets[i] > 4096) {
1830                         if ((unsigned long long)lseek64(destfd[i], destoffsets[i]+stripes*chunk*odata, 0) !=
1831                             destoffsets[i]+stripes*chunk*odata)
1832                                 break;
1833                         if (write(destfd[i], &bsb, 512) != 512)
1834                                 break;
1835                 }
1836                 fsync(destfd[i]);
1837                 rv = 0;
1838         }
1839
1840         return rv;
1841 }
1842
1843 /* in 2.6.30, the value reported by sync_completed can be
1844  * less that it should be by one stripe.
1845  * This only happens when reshape hits sync_max and pauses.
1846  * So allow wait_backup to either extent sync_max further
1847  * than strictly necessary, or return before the
1848  * sync has got quite as far as we would really like.
1849  * This is what 'blocks2' is for.
1850  * The various caller give appropriate values so that
1851  * every works.
1852  */
1853 /* FIXME return value is often ignored */
1854 static int wait_backup(struct mdinfo *sra,
1855                 unsigned long long offset, /* per device */
1856                 unsigned long long blocks, /* per device */
1857                 unsigned long long blocks2, /* per device - hack */
1858                 int dests, int *destfd, unsigned long long *destoffsets,
1859                 int part)
1860 {
1861         /* Wait for resync to pass the section that was backed up
1862          * then erase the backup and allow IO
1863          */
1864         int fd = sysfs_get_fd(sra, NULL, "sync_completed");
1865         unsigned long long completed;
1866         int i;
1867         int rv;
1868
1869         if (fd < 0)
1870                 return -1;
1871         sysfs_set_num(sra, NULL, "sync_max", offset + blocks + blocks2);
1872         if (offset == 0)
1873                 sysfs_set_str(sra, NULL, "sync_action", "reshape");
1874         do {
1875                 char action[20];
1876                 fd_set rfds;
1877                 FD_ZERO(&rfds);
1878                 FD_SET(fd, &rfds);
1879                 select(fd+1, NULL, NULL, &rfds, NULL);
1880                 if (sysfs_fd_get_ll(fd, &completed) < 0) {
1881                         close(fd);
1882                         return -1;
1883                 }
1884                 if (sysfs_get_str(sra, NULL, "sync_action",
1885                                   action, 20) > 0 &&
1886                     strncmp(action, "reshape", 7) != 0)
1887                         break;
1888         } while (completed < offset + blocks);
1889         close(fd);
1890
1891         if (part) {
1892                 bsb.arraystart2 = __cpu_to_le64(0);
1893                 bsb.length2 = __cpu_to_le64(0);
1894         } else {
1895                 bsb.arraystart = __cpu_to_le64(0);
1896                 bsb.length = __cpu_to_le64(0);
1897         }
1898         bsb.mtime = __cpu_to_le64(time(0));
1899         rv = 0;
1900         for (i = 0; i < dests; i++) {
1901                 bsb.devstart = __cpu_to_le64(destoffsets[i]/512);
1902                 bsb.sb_csum = bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb));
1903                 if (memcmp(bsb.magic, "md_backup_data-2", 16) == 0)
1904                         bsb.sb_csum2 = bsb_csum((char*)&bsb,
1905                                                 ((char*)&bsb.sb_csum2)-((char*)&bsb));
1906                 if ((unsigned long long)lseek64(destfd[i], destoffsets[i]-4096, 0) !=
1907                     destoffsets[i]-4096)
1908                         rv = -1;
1909                 if (rv == 0 && 
1910                     write(destfd[i], &bsb, 512) != 512)
1911                         rv = -1;
1912                 fsync(destfd[i]);
1913         }
1914         return rv;
1915 }
1916
1917 static void fail(char *msg)
1918 {
1919         int rv;
1920         rv = (write(2, msg, strlen(msg)) != (int)strlen(msg));
1921         rv |= (write(2, "\n", 1) != 1);
1922         exit(rv ? 1 : 2);
1923 }
1924
1925 static char *abuf, *bbuf;
1926 static unsigned long long abuflen;
1927 static void validate(int afd, int bfd, unsigned long long offset)
1928 {
1929         /* check that the data in the backup against the array.
1930          * This is only used for regression testing and should not
1931          * be used while the array is active
1932          */
1933         if (afd < 0)
1934                 return;
1935         lseek64(bfd, offset - 4096, 0);
1936         if (read(bfd, &bsb2, 512) != 512)
1937                 fail("cannot read bsb");
1938         if (bsb2.sb_csum != bsb_csum((char*)&bsb2,
1939                                      ((char*)&bsb2.sb_csum)-((char*)&bsb2)))
1940                 fail("first csum bad");
1941         if (memcmp(bsb2.magic, "md_backup_data", 14) != 0)
1942                 fail("magic is bad");
1943         if (memcmp(bsb2.magic, "md_backup_data-2", 16) == 0 &&
1944             bsb2.sb_csum2 != bsb_csum((char*)&bsb2,
1945                                      ((char*)&bsb2.sb_csum2)-((char*)&bsb2)))
1946                 fail("second csum bad");
1947
1948         if (__le64_to_cpu(bsb2.devstart)*512 != offset)
1949                 fail("devstart is wrong");
1950
1951         if (bsb2.length) {
1952                 unsigned long long len = __le64_to_cpu(bsb2.length)*512;
1953
1954                 if (abuflen < len) {
1955                         free(abuf);
1956                         free(bbuf);
1957                         abuflen = len;
1958                         if (posix_memalign((void**)&abuf, 4096, abuflen) ||
1959                             posix_memalign((void**)&bbuf, 4096, abuflen)) {
1960                                 abuflen = 0;
1961                                 /* just stop validating on mem-alloc failure */
1962                                 return;
1963                         }
1964                 }
1965
1966                 lseek64(bfd, offset, 0);
1967                 if ((unsigned long long)read(bfd, bbuf, len) != len) {
1968                         //printf("len %llu\n", len);
1969                         fail("read first backup failed");
1970                 }
1971                 lseek64(afd, __le64_to_cpu(bsb2.arraystart)*512, 0);
1972                 if ((unsigned long long)read(afd, abuf, len) != len)
1973                         fail("read first from array failed");
1974                 if (memcmp(bbuf, abuf, len) != 0) {
1975                         #if 0
1976                         int i;
1977                         printf("offset=%llu len=%llu\n",
1978                                (unsigned long long)__le64_to_cpu(bsb2.arraystart)*512, len);
1979                         for (i=0; i<len; i++)
1980                                 if (bbuf[i] != abuf[i]) {
1981                                         printf("first diff byte %d\n", i);
1982                                         break;
1983                                 }
1984                         #endif
1985                         fail("data1 compare failed");
1986                 }
1987         }
1988         if (bsb2.length2) {
1989                 unsigned long long len = __le64_to_cpu(bsb2.length2)*512;
1990
1991                 if (abuflen < len) {
1992                         free(abuf);
1993                         free(bbuf);
1994                         abuflen = len;
1995                         abuf = malloc(abuflen);
1996                         bbuf = malloc(abuflen);
1997                 }
1998
1999                 lseek64(bfd, offset+__le64_to_cpu(bsb2.devstart2)*512, 0);
2000                 if ((unsigned long long)read(bfd, bbuf, len) != len)
2001                         fail("read second backup failed");
2002                 lseek64(afd, __le64_to_cpu(bsb2.arraystart2)*512, 0);
2003                 if ((unsigned long long)read(afd, abuf, len) != len)
2004                         fail("read second from array failed");
2005                 if (memcmp(bbuf, abuf, len) != 0)
2006                         fail("data2 compare failed");
2007         }
2008 }
2009
2010 static int child_grow(int afd, struct mdinfo *sra, unsigned long stripes,
2011                       int *fds, unsigned long long *offsets,
2012                       int disks, int chunk, int level, int layout, int data,
2013                       int dests, int *destfd, unsigned long long *destoffsets)
2014 {
2015         char *buf;
2016         int degraded = 0;
2017
2018         if (posix_memalign((void**)&buf, 4096, disks * chunk))
2019                 /* Don't start the 'reshape' */
2020                 return 0;
2021         sysfs_set_num(sra, NULL, "suspend_hi", 0);
2022         sysfs_set_num(sra, NULL, "suspend_lo", 0);
2023         grow_backup(sra, 0, stripes,
2024                     fds, offsets, disks, chunk, level, layout,
2025                     dests, destfd, destoffsets,
2026                     0, &degraded, buf);
2027         validate(afd, destfd[0], destoffsets[0]);
2028         wait_backup(sra, 0, stripes * (chunk / 512), stripes * (chunk / 512),
2029                     dests, destfd, destoffsets,
2030                     0);
2031         sysfs_set_num(sra, NULL, "suspend_lo", (stripes * (chunk/512)) * data);
2032         free(buf);
2033         /* FIXME this should probably be numeric */
2034         sysfs_set_str(sra, NULL, "sync_max", "max");
2035         return 1;
2036 }
2037
2038 static int child_shrink(int afd, struct mdinfo *sra, unsigned long stripes,
2039                         int *fds, unsigned long long *offsets,
2040                         int disks, int chunk, int level, int layout, int data,
2041                         int dests, int *destfd, unsigned long long *destoffsets)
2042 {
2043         char *buf;
2044         unsigned long long start;
2045         int rv;
2046         int degraded = 0;
2047
2048         if (posix_memalign((void**)&buf, 4096, disks * chunk))
2049                 return 0;
2050         start = sra->component_size - stripes * (chunk/512);
2051         sysfs_set_num(sra, NULL, "sync_max", start);
2052         sysfs_set_str(sra, NULL, "sync_action", "reshape");
2053         sysfs_set_num(sra, NULL, "suspend_lo", 0);
2054         sysfs_set_num(sra, NULL, "suspend_hi", 0);
2055         rv = wait_backup(sra, 0, start - stripes * (chunk/512), stripes * (chunk/512),
2056                          dests, destfd, destoffsets, 0);
2057         if (rv < 0)
2058                 return 0;
2059         grow_backup(sra, 0, stripes,
2060                     fds, offsets,
2061                     disks, chunk, level, layout,
2062                     dests, destfd, destoffsets,
2063                     0, &degraded, buf);
2064         validate(afd, destfd[0], destoffsets[0]);
2065         wait_backup(sra, start, stripes*(chunk/512), 0,
2066                     dests, destfd, destoffsets, 0);
2067         sysfs_set_num(sra, NULL, "suspend_lo", (stripes * (chunk/512)) * data);
2068         free(buf);
2069         /* FIXME this should probably be numeric */
2070         sysfs_set_str(sra, NULL, "sync_max", "max");
2071         return 1;
2072 }
2073
2074 static int child_same_size(int afd, struct mdinfo *sra, unsigned long stripes,
2075                            int *fds, unsigned long long *offsets,
2076                            unsigned long long start,
2077                            int disks, int chunk, int level, int layout, int data,
2078                            int dests, int *destfd, unsigned long long *destoffsets)
2079 {
2080         unsigned long long size;
2081         unsigned long tailstripes = stripes;
2082         int part;
2083         char *buf;
2084         unsigned long long speed;
2085         int degraded = 0;
2086
2087
2088         if (posix_memalign((void**)&buf, 4096, disks * chunk))
2089                 return 0;
2090
2091         sysfs_set_num(sra, NULL, "suspend_lo", 0);
2092         sysfs_set_num(sra, NULL, "suspend_hi", 0);
2093
2094         sysfs_get_ll(sra, NULL, "sync_speed_min", &speed);
2095         sysfs_set_num(sra, NULL, "sync_speed_min", 200000);
2096
2097         grow_backup(sra, start, stripes,
2098                     fds, offsets,
2099                     disks, chunk, level, layout,
2100                     dests, destfd, destoffsets,
2101                     0, &degraded, buf);
2102         grow_backup(sra, (start + stripes) * (chunk/512), stripes,
2103                     fds, offsets,
2104                     disks, chunk, level, layout,
2105                     dests, destfd, destoffsets,
2106                     1, &degraded, buf);
2107         validate(afd, destfd[0], destoffsets[0]);
2108         part = 0;
2109         start += stripes * 2; /* where to read next */
2110         size = sra->component_size / (chunk/512);
2111         while (start < size) {
2112                 if (wait_backup(sra, (start-stripes*2)*(chunk/512),
2113                                 stripes*(chunk/512), 0,
2114                                 dests, destfd, destoffsets,
2115                                 part) < 0)
2116                         return 0;
2117                 sysfs_set_num(sra, NULL, "suspend_lo", start*(chunk/512) * data);
2118                 if (start + stripes > size)
2119                         tailstripes = (size - start);
2120
2121                 grow_backup(sra, start*(chunk/512), tailstripes,
2122                             fds, offsets,
2123                             disks, chunk, level, layout,
2124                             dests, destfd, destoffsets,
2125                             part, &degraded, buf);
2126                 start += stripes;
2127                 part = 1 - part;
2128                 validate(afd, destfd[0], destoffsets[0]);
2129         }
2130         if (wait_backup(sra, (start-stripes*2) * (chunk/512), stripes * (chunk/512), 0,
2131                         dests, destfd, destoffsets,
2132                         part) < 0)
2133                 return 0;
2134         sysfs_set_num(sra, NULL, "suspend_lo", ((start-stripes)*(chunk/512)) * data);
2135         wait_backup(sra, (start-stripes) * (chunk/512), tailstripes * (chunk/512), 0,
2136                     dests, destfd, destoffsets,
2137                     1-part);
2138         sysfs_set_num(sra, NULL, "suspend_lo", (size*(chunk/512)) * data);
2139         sysfs_set_num(sra, NULL, "sync_speed_min", speed);
2140         free(buf);
2141         return 1;
2142 }
2143
2144 /*
2145  * If any spare contains md_back_data-1 which is recent wrt mtime,
2146  * write that data into the array and update the super blocks with
2147  * the new reshape_progress
2148  */
2149 int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt,
2150                  char *backup_file, int verbose)
2151 {
2152         int i, j;
2153         int old_disks;
2154         unsigned long long *offsets;
2155         unsigned long long  nstripe, ostripe;
2156         int ndata, odata;
2157
2158         if (info->new_level != info->array.level)
2159                 return 1; /* Cannot handle level changes (they are instantaneous) */
2160
2161         odata = info->array.raid_disks - info->delta_disks - 1;
2162         if (info->array.level == 6) odata--; /* number of data disks */
2163         ndata = info->array.raid_disks - 1;
2164         if (info->new_level == 6) ndata--;
2165
2166         old_disks = info->array.raid_disks - info->delta_disks;
2167
2168         if (info->delta_disks <= 0)
2169                 /* Didn't grow, so the backup file must have
2170                  * been used
2171                  */
2172                 old_disks = cnt;
2173         for (i=old_disks-(backup_file?1:0); i<cnt; i++) {
2174                 struct mdinfo dinfo;
2175                 int fd;
2176                 int bsbsize;
2177                 char *devname, namebuf[20];
2178
2179                 /* This was a spare and may have some saved data on it.
2180                  * Load the superblock, find and load the
2181                  * backup_super_block.
2182                  * If either fail, go on to next device.
2183                  * If the backup contains no new info, just return
2184                  * else restore data and update all superblocks
2185                  */
2186                 if (i == old_disks-1) {
2187                         fd = open(backup_file, O_RDONLY);
2188                         if (fd<0) {
2189                                 fprintf(stderr, Name ": backup file %s inaccessible: %s\n",
2190                                         backup_file, strerror(errno));
2191                                 continue;
2192                         }
2193                         devname = backup_file;
2194                 } else {
2195                         fd = fdlist[i];
2196                         if (fd < 0)
2197                                 continue;
2198                         if (st->ss->load_super(st, fd, NULL))
2199                                 continue;
2200
2201                         st->ss->getinfo_super(st, &dinfo, NULL);
2202                         st->ss->free_super(st);
2203
2204                         if (lseek64(fd,
2205                                     (dinfo.data_offset + dinfo.component_size - 8) <<9,
2206                                     0) < 0) {
2207                                 fprintf(stderr, Name ": Cannot seek on device %d\n", i);
2208                                 continue; /* Cannot seek */
2209                         }
2210                         sprintf(namebuf, "device-%d", i);
2211                         devname = namebuf;
2212                 }
2213                 if (read(fd, &bsb, sizeof(bsb)) != sizeof(bsb)) {
2214                         if (verbose)
2215                                 fprintf(stderr, Name ": Cannot read from %s\n", devname);
2216                         continue; /* Cannot read */
2217                 }
2218                 if (memcmp(bsb.magic, "md_backup_data-1", 16) != 0 &&
2219                     memcmp(bsb.magic, "md_backup_data-2", 16) != 0) {
2220                         if (verbose)
2221                                 fprintf(stderr, Name ": No backup metadata on %s\n", devname);
2222                         continue;
2223                 }
2224                 if (bsb.sb_csum != bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb))) {
2225                         if (verbose)
2226                                 fprintf(stderr, Name ": Bad backup-metadata checksum on %s\n", devname);
2227                         continue; /* bad checksum */
2228                 }
2229                 if (memcmp(bsb.magic, "md_backup_data-2", 16) == 0 &&
2230                     bsb.sb_csum2 != bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum2)-((char*)&bsb))) {
2231                         if (verbose)
2232                                 fprintf(stderr, Name ": Bad backup-metadata checksum2 on %s\n", devname);
2233                         continue; /* Bad second checksum */
2234                 }
2235                 if (memcmp(bsb.set_uuid,info->uuid, 16) != 0) {
2236                         if (verbose)
2237                                 fprintf(stderr, Name ": Wrong uuid on backup-metadata on %s\n", devname);
2238                         continue; /* Wrong uuid */
2239                 }
2240
2241                 /* array utime and backup-mtime should be updated at much the same time, but it seems that
2242                  * sometimes they aren't... So allow considerable flexability in matching, and allow
2243                  * this test to be overridden by an environment variable.
2244                  */
2245                 if (info->array.utime > (int)__le64_to_cpu(bsb.mtime) + 2*60*60 ||
2246                     info->array.utime < (int)__le64_to_cpu(bsb.mtime) - 10*60) {
2247                         if (check_env("MDADM_GROW_ALLOW_OLD")) {
2248                                 fprintf(stderr, Name ": accepting backup with timestamp %lu "
2249                                         "for array with timestamp %lu\n",
2250                                         (unsigned long)__le64_to_cpu(bsb.mtime),
2251                                         (unsigned long)info->array.utime);
2252                         } else {
2253                                 if (verbose)
2254                                         fprintf(stderr, Name ": too-old timestamp on "
2255                                                 "backup-metadata on %s\n", devname);
2256                                 continue; /* time stamp is too bad */
2257                         }
2258                 }
2259
2260                 if (bsb.magic[15] == '1') {
2261                 if (info->delta_disks >= 0) {
2262                         /* reshape_progress is increasing */
2263                         if (__le64_to_cpu(bsb.arraystart) + __le64_to_cpu(bsb.length) <
2264                             info->reshape_progress) {
2265                         nonew:
2266                                 if (verbose)
2267                                         fprintf(stderr, Name ": backup-metadata found on %s but is not needed\n", devname);
2268                                 continue; /* No new data here */
2269                         }
2270                 } else {
2271                         /* reshape_progress is decreasing */
2272                         if (__le64_to_cpu(bsb.arraystart) >=
2273                             info->reshape_progress)
2274                                 goto nonew; /* No new data here */
2275                 }
2276                 } else {
2277                 if (info->delta_disks >= 0) {
2278                         /* reshape_progress is increasing */
2279                         if (__le64_to_cpu(bsb.arraystart) + __le64_to_cpu(bsb.length) <
2280                             info->reshape_progress &&
2281                             __le64_to_cpu(bsb.arraystart2) + __le64_to_cpu(bsb.length2) <
2282                             info->reshape_progress)
2283                                 goto nonew; /* No new data here */
2284                 } else {
2285                         /* reshape_progress is decreasing */
2286                         if (__le64_to_cpu(bsb.arraystart) >=
2287                             info->reshape_progress &&
2288                             __le64_to_cpu(bsb.arraystart2) >=
2289                             info->reshape_progress)
2290                                 goto nonew; /* No new data here */
2291                 }
2292                 }
2293                 if (lseek64(fd, __le64_to_cpu(bsb.devstart)*512, 0)< 0) {
2294                 second_fail:
2295                         if (verbose)
2296                                 fprintf(stderr, Name ": Failed to verify secondary backup-metadata block on %s\n",
2297                                         devname);
2298                         continue; /* Cannot seek */
2299                 }
2300                 /* There should be a duplicate backup superblock 4k before here */
2301                 if (lseek64(fd, -4096, 1) < 0 ||
2302                     read(fd, &bsb2, sizeof(bsb2)) != sizeof(bsb2))
2303                         goto second_fail; /* Cannot find leading superblock */
2304                 if (bsb.magic[15] == '1')
2305                         bsbsize = offsetof(struct mdp_backup_super, pad1);
2306                 else
2307                         bsbsize = offsetof(struct mdp_backup_super, pad);
2308                 if (memcmp(&bsb2, &bsb, bsbsize) != 0)
2309                         goto second_fail; /* Cannot find leading superblock */
2310
2311                 /* Now need the data offsets for all devices. */
2312                 offsets = malloc(sizeof(*offsets)*info->array.raid_disks);
2313                 for(j=0; j<info->array.raid_disks; j++) {
2314                         if (fdlist[j] < 0)
2315                                 continue;
2316                         if (st->ss->load_super(st, fdlist[j], NULL))
2317                                 /* FIXME should be this be an error */
2318                                 continue;
2319                         st->ss->getinfo_super(st, &dinfo, NULL);
2320                         st->ss->free_super(st);
2321                         offsets[j] = dinfo.data_offset * 512;
2322                 }
2323                 printf(Name ": restoring critical section\n");
2324
2325                 if (restore_stripes(fdlist, offsets,
2326                                     info->array.raid_disks,
2327                                     info->new_chunk,
2328                                     info->new_level,
2329                                     info->new_layout,
2330                                     fd, __le64_to_cpu(bsb.devstart)*512,
2331                                     __le64_to_cpu(bsb.arraystart)*512,
2332                                     __le64_to_cpu(bsb.length)*512)) {
2333                         /* didn't succeed, so giveup */
2334                         if (verbose)
2335                                 fprintf(stderr, Name ": Error restoring backup from %s\n",
2336                                         devname);
2337                         return 1;
2338                 }
2339                 
2340                 if (bsb.magic[15] == '2' &&
2341                     restore_stripes(fdlist, offsets,
2342                                     info->array.raid_disks,
2343                                     info->new_chunk,
2344                                     info->new_level,
2345                                     info->new_layout,
2346                                     fd, __le64_to_cpu(bsb.devstart)*512 +
2347                                     __le64_to_cpu(bsb.devstart2)*512,
2348                                     __le64_to_cpu(bsb.arraystart2)*512,
2349                                     __le64_to_cpu(bsb.length2)*512)) {
2350                         /* didn't succeed, so giveup */
2351                         if (verbose)
2352                                 fprintf(stderr, Name ": Error restoring second backup from %s\n",
2353                                         devname);
2354                         return 1;
2355                 }
2356
2357
2358                 /* Ok, so the data is restored. Let's update those superblocks. */
2359
2360                 if (info->delta_disks >= 0) {
2361                         info->reshape_progress = __le64_to_cpu(bsb.arraystart) +
2362                                 __le64_to_cpu(bsb.length);
2363                         if (bsb.magic[15] == '2') {
2364                                 unsigned long long p2 = __le64_to_cpu(bsb.arraystart2) +
2365                                         __le64_to_cpu(bsb.length2);
2366                                 if (p2 > info->reshape_progress)
2367                                         info->reshape_progress = p2;
2368                         }
2369                 } else {
2370                         info->reshape_progress = __le64_to_cpu(bsb.arraystart);
2371                         if (bsb.magic[15] == '2') {
2372                                 unsigned long long p2 = __le64_to_cpu(bsb.arraystart2);
2373                                 if (p2 < info->reshape_progress)
2374                                         info->reshape_progress = p2;
2375                         }
2376                 }
2377                 for (j=0; j<info->array.raid_disks; j++) {
2378                         if (fdlist[j] < 0) continue;
2379                         if (st->ss->load_super(st, fdlist[j], NULL))
2380                                 continue;
2381                         st->ss->getinfo_super(st, &dinfo, NULL);
2382                         dinfo.reshape_progress = info->reshape_progress;
2383                         st->ss->update_super(st, &dinfo,
2384                                              "_reshape_progress",
2385                                              NULL,0, 0, NULL);
2386                         st->ss->store_super(st, fdlist[j]);
2387                         st->ss->free_super(st);
2388                 }
2389                 return 0;
2390         }
2391         /* Didn't find any backup data, try to see if any
2392          * was needed.
2393          */
2394         if (info->delta_disks < 0) {
2395                 /* When shrinking, the critical section is at the end.
2396                  * So see if we are before the critical section.
2397                  */
2398                 unsigned long long first_block;
2399                 nstripe = ostripe = 0;
2400                 first_block = 0;
2401                 while (ostripe >= nstripe) {
2402                         ostripe += info->array.chunk_size / 512;
2403                         first_block = ostripe * odata;
2404                         nstripe = first_block / ndata / (info->new_chunk/512) *
2405                                 (info->new_chunk/512);
2406                 }
2407
2408                 if (info->reshape_progress >= first_block)
2409                         return 0;
2410         }
2411         if (info->delta_disks > 0) {
2412                 /* See if we are beyond the critical section. */
2413                 unsigned long long last_block;
2414                 nstripe = ostripe = 0;
2415                 last_block = 0;
2416                 while (nstripe >= ostripe) {
2417                         nstripe += info->new_chunk / 512;
2418                         last_block = nstripe * ndata;
2419                         ostripe = last_block / odata / (info->array.chunk_size/512) *
2420                                 (info->array.chunk_size/512);
2421                 }
2422
2423                 if (info->reshape_progress >= last_block)
2424                         return 0;
2425         }
2426         /* needed to recover critical section! */
2427         if (verbose)
2428                 fprintf(stderr, Name ": Failed to find backup of critical section\n");
2429         return 1;
2430 }
2431
2432 int Grow_continue(int mdfd, struct supertype *st, struct mdinfo *info,
2433                   char *backup_file)
2434 {
2435         /* Array is assembled and ready to be started, but
2436          * monitoring is probably required.
2437          * So:
2438          *   - start read-only
2439          *   - set upper bound for resync
2440          *   - initialise the 'suspend' boundaries
2441          *   - switch to read-write
2442          *   - fork and continue monitoring
2443          */
2444         int err;
2445         int backup_list[1];
2446         unsigned long long backup_offsets[1];
2447         int odisks, ndisks, ochunk, nchunk,odata,ndata;
2448         unsigned long a,b,blocks,stripes;
2449         int backup_fd;
2450         int *fds;
2451         unsigned long long *offsets;
2452         int d;
2453         struct mdinfo *sra, *sd;
2454         int rv;
2455         unsigned long cache;
2456         int done = 0;
2457
2458         err = sysfs_set_str(info, NULL, "array_state", "readonly");
2459         if (err)
2460                 return err;
2461
2462         /* make sure reshape doesn't progress until we are ready */
2463         sysfs_set_str(info, NULL, "sync_max", "0");
2464         sysfs_set_str(info, NULL, "array_state", "active"); /* FIXME or clean */
2465
2466         sra = sysfs_read(-1, devname2devnum(info->sys_name),
2467                          GET_COMPONENT|GET_DEVS|GET_OFFSET|GET_STATE|
2468                          GET_CACHE);
2469         if (!sra)
2470                 return 1;
2471
2472         /* ndisks is not growing, so raid_disks is old and +delta is new */
2473         odisks = info->array.raid_disks;
2474         ndisks = odisks + info->delta_disks;
2475         odata = odisks - 1;
2476         ndata = ndisks - 1;
2477         if (info->array.level == 6) {
2478                 odata--;
2479                 ndata--;
2480         }
2481         ochunk = info->array.chunk_size;
2482         nchunk = info->new_chunk;
2483
2484         a = (ochunk/512) * odata;
2485         b = (nchunk/512) * ndata;
2486         /* Find GCD */
2487         while (a != b) {
2488                 if (a < b)
2489                         b -= a;
2490                 if (b < a)
2491                         a -= b;
2492         }
2493         /* LCM == product / GCD */
2494         blocks = (ochunk/512) * (nchunk/512) * odata * ndata / a;
2495
2496         if (ndata == odata)
2497                 while (blocks * 32 < sra->component_size &&
2498                        blocks < 16*1024*2)
2499                         blocks *= 2;
2500         stripes = blocks / (info->array.chunk_size/512) / odata;
2501
2502         /* check that the internal stripe cache is
2503          * large enough, or it won't work.
2504          */
2505         cache = (nchunk < ochunk) ? ochunk : nchunk;
2506         cache = cache * 4 / 4096;
2507         if (cache < blocks / 8 / odisks + 16)
2508                 /* Make it big enough to hold 'blocks' */
2509                 cache = blocks / 8 / odisks + 16;
2510         if (sra->cache_size < cache)
2511                 sysfs_set_num(sra, NULL, "stripe_cache_size",
2512                               cache+1);
2513
2514         memset(&bsb, 0, 512);
2515         memcpy(bsb.magic, "md_backup_data-1", 16);
2516         memcpy(&bsb.set_uuid, info->uuid, 16);
2517         bsb.mtime = __cpu_to_le64(time(0));
2518         bsb.devstart2 = blocks;
2519
2520         backup_fd = open(backup_file, O_RDWR|O_CREAT, S_IRUSR | S_IWUSR);
2521         backup_list[0] = backup_fd;
2522         backup_offsets[0] = 8 * 512;
2523         fds = malloc(odisks * sizeof(fds[0]));
2524         offsets = malloc(odisks * sizeof(offsets[0]));
2525         for (d=0; d<odisks; d++)
2526                 fds[d] = -1;
2527
2528         for (sd = sra->devs; sd; sd = sd->next) {
2529                 if (sd->disk.state & (1<<MD_DISK_FAULTY))
2530                         continue;
2531                 if (sd->disk.state & (1<<MD_DISK_SYNC)) {
2532                         char *dn = map_dev(sd->disk.major,
2533                                            sd->disk.minor, 1);
2534                         fds[sd->disk.raid_disk]
2535                                 = dev_open(dn, O_RDONLY);
2536                         offsets[sd->disk.raid_disk] = sd->data_offset*512;
2537                         if (fds[sd->disk.raid_disk] < 0) {
2538                                 fprintf(stderr, Name ": %s: cannot open component %s\n",
2539                                         info->sys_name, dn?dn:"-unknown-");
2540                                 rv = 1;
2541                                 goto release;
2542                         }
2543                         free(dn);
2544                 }
2545         }
2546
2547         switch(fork()) {
2548         case 0:
2549                 close(mdfd);
2550                 mlockall(MCL_FUTURE);
2551                 if (info->delta_disks < 0)
2552                         done = child_shrink(-1, info, stripes,
2553                                             fds, offsets,
2554                                             info->array.raid_disks,
2555                                             info->array.chunk_size,
2556                                             info->array.level, info->array.layout,
2557                                             odata,
2558                                             1, backup_list, backup_offsets);
2559                 else if (info->delta_disks == 0) {
2560                         /* The 'start' is a per-device stripe number.
2561                          * reshape_progress is a per-array sector number.
2562                          * So divide by ndata * chunk_size
2563                          */
2564                         unsigned long long start = info->reshape_progress / ndata;
2565                         start /= (info->array.chunk_size/512);
2566                         done = child_same_size(-1, info, stripes,
2567                                                fds, offsets,
2568                                                start,
2569                                                info->array.raid_disks,
2570                                                info->array.chunk_size,
2571                                                info->array.level, info->array.layout,
2572                                                odata,
2573                                                1, backup_list, backup_offsets);
2574                 }
2575                 if (backup_file && done)
2576                         unlink(backup_file);
2577                 /* FIXME should I intuit a level change */
2578                 exit(0);
2579         case -1:
2580                 fprintf(stderr, Name ": Cannot run child to continue monitoring reshape: %s\n",
2581                         strerror(errno));
2582                 return 1;
2583         default:
2584                 break;
2585         }
2586 release:
2587         return 0;
2588 }
2589
2590