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Put a 'canary' block in front of the backup 

.. so corruptio can be detected.

Signed-off-by: Neil Brown <neilb@suse.de>
This commit is contained in:
Neil Brown 2006-03-27 04:14:43 +00:00
parent ca9ce4ec3e
commit 2efedc7bd2
2 changed files with 36 additions and 8 deletions
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7
ChangeLog
View File

@ -1,3 +1,10 @@
Changes Prior to 2.4 release
- Rewrite 'reshape' support including performing a backup
of the critical region for a raid5 growth, and restoring that
backup after a crash.
- Put a 'canary' at each end of the backup so a corruption
can be more easily detected.
Changes Prior to 2.3.1 release
- Fixed -O2 compile so I could make and RPM.
- Type cast number to be printed %llu so it compiles on 64bit

37
Grow.c
View File

@ -689,13 +689,32 @@ int Grow_reshape(char *devname, int fd, int quiet,
spares = sra->spares;
/* Decide offset for the backup and llseek the spares */
memcpy(bsb.magic, "md_backup_data-1", 16);
st->ss->uuid_from_super((int*)&bsb.set_uuid, super);
bsb.mtime = __cpu_to_le64(time(0));
bsb.arraystart = 0;
bsb.length = __cpu_to_le64(last_block);
/* Decide offset for the backup, llseek the spares, and write
* a leading superblock 4K earlier.
*/
for (i=array.raid_disks; i<d; i++) {
char buf[4096];
offsets[i] += sra->component_size - last_block - 8;
if (lseek64(fdlist[i], offsets[i]<<9, 0) != offsets[i]<<9) {
if (lseek64(fdlist[i], (offsets[i]<<9) - 4096, 0)
!= (offsets[i]<<9) - 4096) {
fprintf(stderr, Name ": could not seek...\n");
goto abort;
}
memset(buf, 0, sizeof(buf));
bsb.devstart = __cpu_to_le64(offsets[i]);
bsb.sb_csum = bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb));
memcpy(buf, &bsb, sizeof(bsb));
if (write(fdlist[i], buf, 4096) != 4096) {
fprintf(stderr, Name ": could not write leading superblock\n");
goto abort;
}
}
array.level = nlevel;
array.raid_disks = ndisks;
@ -728,12 +747,7 @@ int Grow_reshape(char *devname, int fd, int quiet,
devname);
goto abort_resume;
}
/* FIXME write superblocks */
memcpy(bsb.magic, "md_backup_data-1", 16);
st->ss->uuid_from_super((int*)&bsb.set_uuid, super);
bsb.mtime = __cpu_to_le64(time(0));
bsb.arraystart = 0;
bsb.length = __cpu_to_le64(last_block);
for (i=odisks; i<d ; i++) {
bsb.devstart = __cpu_to_le64(offsets[i]);
bsb.sb_csum = bsb_csum((char*)&bsb, ((char*)&bsb.sb_csum)-((char*)&bsb));
@ -823,6 +837,7 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
struct mdinfo dinfo;
struct mddev_ident_s id;
struct mdp_backup_super bsb;
char buf[4096];
/* This was a spare and may have some saved data on it.
* Load the superblock, find and load the
@ -863,6 +878,12 @@ int Grow_restart(struct supertype *st, struct mdinfo *info, int *fdlist, int cnt
if (lseek64(fdlist[i], __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 ||
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);