Allow resize to backup to a file.

To support resizing an array without a spare, mdadm now understands
  --backup-file=
which should point to a file for storing a backup of critical data.
This can be given to --grow which will create the file, or
--assemble which will restore from the file if needed.

Signed-off-by: Neil Brown <neilb@suse.de>

diff --git a/Assemble.c b/Assemble.c
index a8a331e1d6901b74cbf257880fd15be6ffa9e0e3..f38b1a14d6e26ab09d9eaeb24a718420b3943810 100644 (file)
--- a/Assemble.c
+++ b/Assemble.c
@@ -31,7 +31,7 @@
 
 int Assemble(struct supertype *st, char *mddev, int mdfd,
             mddev_ident_t ident, char *conffile,
-            mddev_dev_t devlist,
+            mddev_dev_t devlist, char *backup_file,
             int readonly, int runstop,
             char *update,
             int verbose, int force)
@@ -585,7 +585,7 @@ int Assemble(struct supertype *st, char *mddev, int mdfd,
                                fdlist[i] = -1;
                }
                if (!err)
-                       err = Grow_restart(st, &info, fdlist, bestcnt);
+                       err = Grow_restart(st, &info, fdlist, bestcnt, backup_file);
                while (i>0) {
                        i--;
                        if (fdlist[i]>=0) close(fdlist[i]);

diff --git a/ChangeLog b/ChangeLog
index 22a97ccd0b19c3f69335ee2f8538c9256c3829f0..4ee2dffc6a7d93342cd669cf440a6cb393f4653b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,7 @@ Changes Prior to 2.4 release
     -   Put a 'canary' at each end of the backup so a corruption
        can be more easily detected.
     -   Remove useless 'ident' arguement from ->getinfo_super method.
+    -   Support --backup-file for backing-up critical section during growth.
 
 Changes Prior to 2.3.1 release
     -   Fixed -O2 compile so I could make and RPM.

diff --git a/Grow.c b/Grow.c
index 04de4550608ed7918ec940401d46dd336daa4ac9..4a225c7342dbd17833015c2e562105afc0ff3215 100644 (file)
--- a/Grow.c
+++ b/Grow.c
@@ -408,7 +408,7 @@ int bsb_csum(char *buf, int len)
        return __cpu_to_le32(csum);
 }
 
-int Grow_reshape(char *devname, int fd, int quiet,
+int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
                 long long size,
                 int level, int layout, int chunksize, int raid_disks)
 {
@@ -625,8 +625,8 @@ int Grow_reshape(char *devname, int fd, int quiet,
                                devname);
                        return 1;
                }
-               if (sra->spares == 0) {
-                       fprintf(stderr, Name ": %s: Cannot grow - need a spare to backup critical section\n",
+               if (sra->spares == 0 && backup_file == NULL) {
+                       fprintf(stderr, Name ": %s: Cannot grow - need a spare or backup-file to backup critical section\n",
                                devname);
                        return 1;
                }
@@ -634,13 +634,13 @@ int Grow_reshape(char *devname, int fd, int quiet,
                nrdisks = array.nr_disks + sra->spares;
                /* Now we need to open all these devices so we can read/write.
                 */
-               fdlist = malloc(nrdisks * sizeof(int));
-               offsets = malloc(nrdisks * sizeof(offsets[0]));
+               fdlist = malloc((1+nrdisks) * sizeof(int));
+               offsets = malloc((1+nrdisks) * sizeof(offsets[0]));
                if (!fdlist || !offsets) {
                        fprintf(stderr, Name ": malloc failed: grow aborted\n");
                        return 1;
                }
-               for (d=0; d< nrdisks; d++)
+               for (d=0; d <= nrdisks; d++)
                        fdlist[d] = -1;
                d = array.raid_disks;
                for (sd = sra->devs; sd; sd=sd->next) {
@@ -674,8 +674,20 @@ int Grow_reshape(char *devname, int fd, int quiet,
                                        " --grow aborted\n", devname, i);
                                goto abort;
                        }
+               spares = sra->spares;
+               if (backup_file) {
+                       fdlist[d] = open(backup_file, O_RDWR|O_CREAT|O_EXCL, 0600);
+                       if (fdlist[d] < 0) {
+                               fprintf(stderr, Name ": %s: cannot create backup file %s: %s\n",
+                                       devname, backup_file, strerror(errno));
+                               goto abort;
+                       }
+                       offsets[d] = 8;
+                       d++;
+                       spares++;
+               }
                if (fdlist[array.raid_disks] < 0) {
-                       fprintf(stderr, Name ": %s: failed to find a spare - --grow aborted\n",
+                       fprintf(stderr, Name ": %s: failed to find a spare and no backup-file given - --grow aborted\n",
                                devname);
                        goto abort;
                }
@@ -687,8 +699,6 @@ int Grow_reshape(char *devname, int fd, int quiet,
                        goto abort;
                }
 
-               spares = sra->spares;
-
 
                memcpy(bsb.magic, "md_backup_data-1", 16);
                st->ss->uuid_from_super((int*)&bsb.set_uuid, super);
@@ -701,7 +711,11 @@ int Grow_reshape(char *devname, int fd, int quiet,
                 */
                for (i=array.raid_disks; i<d; i++) {
                        char buf[4096];
-                       offsets[i] += sra->component_size - last_block - 8;
+                       if (i==d-1 && backup_file) {
+                               /* This is the backup file */
+                               offsets[i] = 8;
+                       } else
+                               offsets[i] += sra->component_size - last_block - 8;
                        if (lseek64(fdlist[i], (offsets[i]<<9) - 4096, 0)
                            != (offsets[i]<<9) - 4096) {
                                fprintf(stderr, Name ": could not seek...\n");
@@ -739,7 +753,7 @@ int Grow_reshape(char *devname, int fd, int quiet,
                err = save_stripes(fdlist, offsets,
                                   odisks, ochunk, olevel, olayout,
                                   spares, fdlist+odisks,
-                                  0ULL, nstripe*512);
+                                  0ULL, last_block*512);
 
                /* abort if there was an error */
                if (err < 0) {
@@ -752,7 +766,8 @@ int Grow_reshape(char *devname, int fd, int quiet,
                        bsb.devstart = __cpu_to_le64(offsets[i]);
                        bsb.sb_csum = bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb));
                        if (lseek64(fdlist[i], (offsets[i]+last_block)<<9, 0) < 0 ||
-                           write(fdlist[i], &bsb, sizeof(bsb)) != sizeof(bsb)) {
+                           write(fdlist[i], &bsb, sizeof(bsb)) != sizeof(bsb) ||
+                           fsync(fdlist[i]) != 0) {
                                fprintf(stderr, Name ": %s: fail to save metadata for critical region backups.\n",
                                        devname);
                                goto abort_resume;
@@ -792,6 +807,8 @@ int Grow_reshape(char *devname, int fd, int quiet,
                                close(fdlist[i]);
                free(fdlist);
                free(offsets);
+               if (backup_file)
+                       unlink(backup_file);
 
                printf(Name ": ... critical section passed.\n");
                break;
@@ -807,6 +824,8 @@ int Grow_reshape(char *devname, int fd, int quiet,
                        close(fdlist[i]);
        free(fdlist);
        free(offsets);
+       if (backup_file)
+               unlink(backup_file);
        return 1;
 
 }
@@ -816,7 +835,7 @@ int Grow_reshape(char *devname, int fd, int quiet,
  * write that data into the array and update the super blocks with
  * the new reshape_progress
  */
-int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt)
+int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt, char *backup_file)
 {
        int i, j;
        int old_disks;
@@ -832,11 +851,12 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
 
        old_disks = info->array.raid_disks - info->delta_disks;
 
-       for (i=old_disks; i<cnt; i++) {
+       for (i=old_disks-(backup_file?1:0); i<cnt; i++) {
                void *super = NULL;
                struct mdinfo dinfo;
                struct mdp_backup_super bsb;
                char buf[4096];
+               int fd;
 
                /* This was a spare and may have some saved data on it.
                 * Load the superblock, find and load the
@@ -845,18 +865,27 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
                 * If the backup contains no new info, just return
                 * else restore data and update all superblocks
                 */
-               if (fdlist[i] < 0)
-                       continue;
-               if (st->ss->load_super(st, fdlist[i], &super, NULL))
-                       continue;
+               if (i == old_disks-1) {
+                       fd = open(backup_file, O_RDONLY);
+                       if (fd<0)
+                               continue;
+                       if (lseek(fd, 4096, 0) != 4096)
+                               continue;
+               } else {
+                       fd = fdlist[i];
+                       if (fd < 0)
+                               continue;
+                       if (st->ss->load_super(st, fd, &super, NULL))
+                               continue;
 
-               st->ss->getinfo_super(&dinfo, super);
-               free(super); super = NULL;
-               if (lseek64(fdlist[i],
-                       (dinfo.data_offset + dinfo.component_size - 8) <<9,
-                           0) < 0)
-                       continue; /* Cannot seek */
-               if (read(fdlist[i], &bsb, sizeof(bsb)) != sizeof(bsb))
+                       st->ss->getinfo_super(&dinfo, super);
+                       free(super); super = NULL;
+                       if (lseek64(fd,
+                                   (dinfo.data_offset + dinfo.component_size - 8) <<9,
+                                   0) < 0)
+                               continue; /* Cannot seek */
+               }
+               if (read(fd, &bsb, sizeof(bsb)) != sizeof(bsb))
                        continue; /* Cannot read */
                if (memcmp(bsb.magic, "md_backup_data-1", 16) != 0)
                        continue;
@@ -875,15 +904,14 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
                    info->reshape_progress)
                        continue; /* No new data here */
 
-               if (lseek64(fdlist[i], __le64_to_cpu(bsb.devstart)*512, 0)< 0)
+               if (lseek64(fd, __le64_to_cpu(bsb.devstart)*512, 0)< 0)
                        continue; /* Cannot seek */
                /* There should be a duplicate backup superblock 4k before here */
-               if (lseek64(fdlist[i], -4096, 1) < 0 ||
-                   read(fdlist[i], buf, 4096) != 4096 ||
+               if (lseek64(fd, -4096, 1) < 0 ||
+                   read(fd, buf, 4096) != 4096 ||
                    memcmp(buf, &bsb, sizeof(buf)) != 0)
                        continue; /* Cannot find leading superblock */
 
-
                /* Now need the data offsets for all devices. */
                offsets = malloc(sizeof(*offsets)*info->array.raid_disks);
                for(j=0; j<info->array.raid_disks; j++) {
@@ -903,7 +931,7 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
                                    info->new_chunk,
                                    info->new_level,
                                    info->new_layout,
-                                   fdlist[i], __le64_to_cpu(bsb.devstart)*512,
+                                   fd, __le64_to_cpu(bsb.devstart)*512,
                                    0, __le64_to_cpu(bsb.length)*512)) {
                        /* didn't succeed, so giveup */
                        return -1;

diff --git a/ReadMe.c b/ReadMe.c
index c508a36e88b992dba8668b27066459f3486de0a6..448e966e43675a458f7a1475883264dd1b9d24ac 100644 (file)
--- a/ReadMe.c
+++ b/ReadMe.c
@@ -172,6 +172,8 @@ struct option long_options[] = {
     {"daemonize", 0, 0, 'f'},
     {"oneshot",   0, 0, '1'},
     {"pid-file",  1, 0, 'i'},
+    /* For Grow */
+    {"backup-file", 1,0, 7},
     
     {0, 0, 0, 0}
 };

diff --git a/mdadm.c b/mdadm.c
index 5347999679631cc5a609a3aecd1f139d754018fb..6e57c5bc2f812a75bf33bd18e9b706813bd7f40d 100644 (file)
--- a/mdadm.c
+++ b/mdadm.c
@@ -62,6 +62,7 @@ int main(int argc, char *argv[])
        int write_behind = 0;
        int bitmap_fd = -1;
        char *bitmap_file = NULL;
+       char *backup_file = NULL;
        int bitmap_chunk = UnSet;
        int SparcAdjust = 0;
        mddev_dev_t devlist = NULL;
@@ -769,6 +770,18 @@ int main(int argc, char *argv[])
                        ident.bitmap_fd = bitmap_fd; /* for Assemble */
                        continue;
 
+               case O(ASSEMBLE, 7):
+               case O(GROW, 7):
+                       /* Specify a file into which grow might place a backup,
+                        * or from which assemble might recover a backup
+                        */
+                       if (backup_file) {
+                               fprintf(stderr, Name ": backup file already specified, rejecting %s\n", optarg);
+                               exit(2);
+                       }
+                       backup_file = optarg;
+                       continue;
+
                case O(GROW,'b'):
                case O(BUILD,'b'):
                case O(CREATE,'b'): /* here we create the bitmap */
@@ -812,8 +825,13 @@ int main(int argc, char *argv[])
                /* We have now processed all the valid options. Anything else is
                 * an error
                 */
-               fprintf(stderr, Name ": option %c not valid in %s mode\n",
-                       opt, map_num(modes, mode));
+               if (option_index > 0)
+                       fprintf(stderr, Name ":option --%s not valid in %s mode\n",
+                               long_options[option_index].name,
+                               map_num(modes, mode));
+               else
+                       fprintf(stderr, Name ": option -%c not valid in %s mode\n",
+                               opt, map_num(modes, mode));
                exit(2);
 
        }
@@ -927,20 +945,24 @@ int main(int argc, char *argv[])
                                        rv |= 1;
                                else {
                                        rv |= Assemble(ss, devlist->devname, mdfd, array_ident, configfile,
-                                                      NULL,
+                                                      NULL, backup_file,
                                                       readonly, runstop, update, verbose-quiet, force);
                                        close(mdfd);
                                }
                        }
                } else if (!scan)
                        rv = Assemble(ss, devlist->devname, mdfd, &ident, configfile,
-                                     devlist->next,
+                                     devlist->next, backup_file,
                                      readonly, runstop, update, verbose-quiet, force);
                else if (devs_found>0) {
                        if (update && devs_found > 1) {
                                fprintf(stderr, Name ": can only update a single array at a time\n");
                                exit(1);
                        }
+                       if (backup_file && devs_found > 1) {
+                               fprintf(stderr, Name ": can only assemble a single array when providing a backup file.\n");
+                               exit(1);
+                       }
                        for (dv = devlist ; dv ; dv=dv->next) {
                                mddev_ident_t array_ident = conf_get_ident(configfile, dv->devname);
                                if (array_ident == NULL) {
@@ -956,7 +978,7 @@ int main(int argc, char *argv[])
                                        continue;
                                }
                                rv |= Assemble(ss, dv->devname, mdfd, array_ident, configfile,
-                                              NULL,
+                                              NULL, backup_file,
                                               readonly, runstop, update, verbose-quiet, force);
                                close(mdfd);
                        }
@@ -966,6 +988,14 @@ int main(int argc, char *argv[])
                                fprintf(stderr, Name ": No arrays found in config file\n");
                                rv = 1;
                        } else
+                               if (update) {
+                                       fprintf(stderr, Name ": --update not meaningful with a --scan assembly.\n");
+                                       exit(1);
+                               }
+                               if (backup_file) {
+                                       fprintf(stderr, Name ": --backup_file not meaningful with a --scan assembly.\n");
+                                       exit(1);
+                               }
                                for (; array_list; array_list = array_list->next) {
                                        mdu_array_info_t array;
                                        mdfd = open_mddev(array_list->devname, 
@@ -980,7 +1010,7 @@ int main(int argc, char *argv[])
                                        else
                                                rv |= Assemble(ss, array_list->devname, mdfd,
                                                               array_list, configfile,
-                                                              NULL,
+                                                              NULL, NULL,
                                                               readonly, runstop, NULL, verbose-quiet, force);
                                        close(mdfd);
                                }
@@ -1155,7 +1185,7 @@ int main(int argc, char *argv[])
                } else if (layout != UnSet)
                        rv = Manage_reconfig(devlist->devname, mdfd, layout);
                else if (size >= 0 || raiddisks)
-                       rv = Grow_reshape(devlist->devname, mdfd, quiet,
+                       rv = Grow_reshape(devlist->devname, mdfd, quiet, backup_file,
                                          size, level, layout, chunk, raiddisks);
                else if (bitmap_file) {
                        if (delay == 0) delay = DEFAULT_BITMAP_DELAY;

diff --git a/mdadm.h b/mdadm.h
index c929be95eccf7eebbc304572b037e11cdd78e6c9..17526237c85f1b7db7b6d5339d41d774f679324d 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -309,16 +309,17 @@ extern int Manage_subdevs(char *devname, int fd,
                          mddev_dev_t devlist, int verbose);
 extern int Grow_Add_device(char *devname, int fd, char *newdev);
 extern int Grow_addbitmap(char *devname, int fd, char *file, int chunk, int delay, int write_behind, int force);
-extern int Grow_reshape(char *devname, int fd, int quiet,
+extern int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
                        long long size,
                        int level, int layout, int chunksize, int raid_disks);
-extern int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt);
+extern int Grow_restart(struct supertype *st, struct mdinfo *info,
+                       int *fdlist, int cnt, char *backup_file);
 
 
 extern int Assemble(struct supertype *st, char *mddev, int mdfd,
                    mddev_ident_t ident,
                    char *conffile,
-                   mddev_dev_t devlist,
+                   mddev_dev_t devlist, char *backup_file,
                    int readonly, int runstop,
                    char *update,
                    int verbose, int force);