[patch 15/58] block: include empty disks in /proc/diskstats

Greg KH
2009-05-06T22:00:42Z

[-- Attachment #1: block-include-empty-disks-in-proc-diskstats.patch --]
[-- Type: text/plain, Size: 2817 bytes --]

2.6.29-stable review patch. If anyone has any objections, please let us know.

------------------

From: Tejun Heo <tj@kernel.org>

commit 71982a409f12c50d011325a4471aa20666bb908d upstream.

/proc/diskstats used to show stats for all disks whether they're
zero-sized or not and their non-zero partitions. Commit
074a7aca7afa6f230104e8e65eba3420263714a5 accidentally changed the
behavior such that it doesn't print out zero sized disks. This patch
implements DISK_PITER_INCL_EMPTY_PART0 flag to partition iterator and
uses it in diskstats_show() such that empty part0 is shown in
/proc/diskstats.

Reported and bisectd by Dianel Collins.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Daniel Collins <solemnwarning@solemnwarning.no-ip.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
block/genhd.c | 12 ++++++++----
include/linux/genhd.h | 1 +
2 files changed, 9 insertions(+), 4 deletions(-)

--- a/block/genhd.c
+++ b/block/genhd.c
@@ -98,7 +98,7 @@ void disk_part_iter_init(struct disk_par

if (flags & DISK_PITER_REVERSE)
piter->idx = ptbl->len - 1;
- else if (flags & DISK_PITER_INCL_PART0)
+ else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
piter->idx = 0;
else
piter->idx = 1;
@@ -134,7 +134,8 @@ struct hd_struct *disk_part_iter_next(st
/* determine iteration parameters */
if (piter->flags & DISK_PITER_REVERSE) {
inc = -1;
- if (piter->flags & DISK_PITER_INCL_PART0)
+ if (piter->flags & (DISK_PITER_INCL_PART0 |
+ DISK_PITER_INCL_EMPTY_PART0))
end = -1;
else
end = 0;
@@ -150,7 +151,10 @@ struct hd_struct *disk_part_iter_next(st
part = rcu_dereference(ptbl->part[piter->idx]);
if (!part)
continue;
- if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects)
+ if (!part->nr_sects &&
+ !(piter->flags & DISK_PITER_INCL_EMPTY) &&
+ !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
+ piter->idx == 0))
continue;

get_device(part_to_dev(part));
@@ -1011,7 +1015,7 @@ static int diskstats_show(struct seq_fil
"\n\n");
*/

- disk_part_iter_init(&piter, gp, DISK_PITER_INCL_PART0);
+ disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
while ((hd = disk_part_iter_next(&piter))) {
cpu = part_stat_lock();
part_round_stats(cpu, hd);
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -214,6 +214,7 @@ static inline void disk_put_part(struct
#define DISK_PITER_REVERSE (1 << 0) /* iterate in the reverse direction */
#define DISK_PITER_INCL_EMPTY (1 << 1) /* include 0-sized parts */
#define DISK_PITER_INCL_PART0 (1 << 2) /* include partition 0 */
+#define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */

struct disk_part_iter {
struct gendisk *disk;