### Comments for ChangeSet
Set desc_nr more sanely.
Currently rdev->desc_nr is set in sync_sbs which is typcially
called just before writing out the superblocks, which is an
odd place to set it.
It is also called when a new disk is added (which is sane) and
when an old disc is imported ... which is quesitonable.
With this patch it is set when a new disk is added, and when
the superblocks are being analysed, which makes lots of sense.
MULTIPATH is particularly an issue here. The old code tried
to figure the desc_nr for an rdev by matching device numbers in
the superblock. This doesn't make a lot of sense as
device numbers can change. Now MULTIPATH components
get sequential desc_nrs.
----------- Diffstat output ------------
./drivers/md/md.c | 40 +++++++++++++++-------------------------
1 files changed, 15 insertions(+), 25 deletions(-)
--- ./drivers/md/md.c 2002/07/18 12:02:00 1.6
+++ ./drivers/md/md.c 2002/07/18 12:02:10 1.7
@@ -876,7 +876,6 @@ static void set_this_disk(mddev_t *mddev
#endif
if (kdev_same(mk_kdev(desc->major,desc->minor), rdev->dev)) {
rdev->sb->this_disk = *desc;
- rdev->desc_nr = desc->number;
ok = 1;
break;
}
@@ -1019,14 +1018,11 @@ static mdk_rdev_t *md_import_device(kdev
goto abort_free;
}
- if (rdev->sb->level != LEVEL_MULTIPATH) {
+ if (rdev->sb->level != LEVEL_MULTIPATH)
rdev->old_dev = mk_kdev(rdev->sb->this_disk.major,
rdev->sb->this_disk.minor);
- rdev->desc_nr = rdev->sb->this_disk.number;
- } else {
+ else
rdev->old_dev = NODEV;
- rdev->desc_nr = -1;
- }
}
INIT_LIST_HEAD(&rdev->same_set);
@@ -1065,7 +1061,7 @@ abort_free:
static int analyze_sbs(mddev_t * mddev)
{
- int out_of_date = 0, i, first;
+ int out_of_date = 0, i;
struct list_head *tmp, *tmp2;
mdk_rdev_t *rdev, *rdev2, *freshest;
mdp_super_t *sb;
@@ -1173,6 +1169,18 @@ static int analyze_sbs(mddev_t * mddev)
}
}
+ /* set rdev->desc_nr for each device.
+ * for MULTIPATH, we just us sequential number as
+ * nothing else is meaningful
+ */
+ i = 0;
+ ITERATE_RDEV(mddev,rdev,tmp) {
+ if (sb->level == LEVEL_MULTIPATH) {
+ rdev->alias_device = !!i;
+ rdev->desc_nr = i++;
+ } else
+ rdev->desc_nr = rdev->sb->this_disk.number;
+ }
/*
* Fix up changed device names ... but only if this disk has a
* recent update time. Use faulty checksum ones too.
@@ -1301,7 +1309,6 @@ static int analyze_sbs(mddev_t * mddev)
* Double check wether all devices mentioned in the
* superblock are in the rdev ring.
*/
- first = 1;
for (i = 0; i < MD_SB_DISKS; i++) {
mdp_disk_t *desc;
kdev_t dev;
@@ -1321,23 +1328,6 @@ static int analyze_sbs(mddev_t * mddev)
if (!rdev) {
MD_BUG();
goto abort;
- }
- /*
- * In the case of Multipath-IO, we have no
- * other information source to find out which
- * disk is which, only the position of the device
- * in the superblock:
- */
- if (mddev->sb->level == LEVEL_MULTIPATH) {
- if ((rdev->desc_nr != -1) && (rdev->desc_nr != i)) {
- MD_BUG();
- goto abort;
- }
- rdev->desc_nr = i;
- if (!first)
- rdev->alias_device = 1;
- else
- first = 0;
}
}
-
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