[Patch mdadm-3.2.2] Fix the fix for the readd bug

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The readd bug fix didn't work due to a faulty test. We need to check
raid_disks to get an upper bound of the found slots to check since
nr_disks only counts good disks and we could have faulty or spares that
aren't counted but amount to an occupied slot.

Signed-off-by: Doug Ledford

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--- mdadm-3.2.2/util.c.readd 2011-06-17 01:15:50.000000000 -0400
+++ mdadm-3.2.2/util.c 2011-07-18 14:43:40.776150946 -0400
@@ -364,19 +364,21 @@ int enough_fd(int fd)
struct mdu_disk_info_s disk;
int avail_disks = 0;
int i;
+ int raid_disks;
char *avail;

if (ioctl(fd, GET_ARRAY_INFO, &array) != 0 ||
array.raid_disks <= 0)
return 0;
avail = calloc(array.raid_disks, 1);
- for (i=0; i < 1024 && array.nr_disks > 0; i++) {
+ raid_disks = array.raid_disks;
+ for (i=0; i < 1024 && raid_disks > 0; i++) {
disk.number = i;
if (ioctl(fd, GET_DISK_INFO, &disk) != 0)
continue;
if (disk.major == 0 && disk.minor == 0)
continue;
- array.nr_disks--;
+ raid_disks--;

if (! (disk.state & (1< continue;

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Re: [Patch mdadm-3.2.2] Fix the fix for the readd bug

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On Wed, 27 Jul 2011 14:30:35 -0400 Doug Ledford wrote:

> The readd bug fix didn't work due to a faulty test. We need to check=20
> raid_disks to get an upper bound of the found slots to check since=20
> nr_disks only counts good disks and we could have faulty or spares that=20
> aren't counted but amount to an occupied slot.
>=20
> Signed-off-by: Doug Ledford

Sorry for late review.

I don't agree with this patch.
'nr_disks' is exactly the number of devices in the mddev->disks list in the
kernel. get_array_info() counts them. This includes failed and spare
devices.

When GET_DISK_INFO is used, these devices will return a meaningful
major/minor and all others will return '0' for major and minor.
So the code should work as is.

Do you remember if you had a case where this failed? Can you describe it?
Can you reproduce it?
Thanks,
NeilBrown


--- mdadm-3.2.2/util.c.readd 2011-06-17 01:15:50.000000000 -0400
+++ mdadm-3.2.2/util.c 2011-07-18 14:43:40.776150946 -0400
@@ -364,19 +364,21 @@ int enough_fd(int fd)
struct mdu_disk_info_s disk;
int avail_disks =3D 0;
int i;
+ int raid_disks;
char *avail;
=20
if (ioctl(fd, GET_ARRAY_INFO, &array) !=3D 0 ||
array.raid_disks <=3D 0)
return 0;
avail =3D calloc(array.raid_disks, 1);
- for (i=3D0; i < 1024 && array.nr_disks > 0; i++) {
+ raid_disks =3D array.raid_disks;
+ for (i=3D0; i < 1024 && raid_disks > 0; i++) {
disk.number =3D i;
if (ioctl(fd, GET_DISK_INFO, &disk) !=3D 0)
continue;
if (disk.major == 0 && disk.minor == 0)
continue;
- array.nr_disks--;
+ raid_disks--;
=20
if (! (disk.state & (1< continue;

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