[PATCH 2/4] partitions: add ->set_capacity block device method

Bartlomiej Zolnierkiewicz
2009-05-31T14:34:41Z

From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Subject: [PATCH] partitions: add ->set_capacity block device method

* Add ->set_capacity block device method and use it in rescan_partitions()
to attempt enabling native capacity of the device upon detecting the
partition which exceeds device capacity.

* Add GENHD_FL_NATIVE_CAPACITY flag to try limit attempts of enabling
native capacity during partition scan.

Together with the consecutive patch implementing ->set_capacity method in
ide-gd device driver this allows automatic disabling of Host Protected Area
(HPA) if any partitions overlapping HPA are detected.

Cc: Robert Hancock <hancockrwd@gmail.com>
Cc: Frans Pop <elendil@planet.nl>
Cc: "Andries E. Brouwer" <Andries.Brouwer@cwi.nl>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
fs/partitions/check.c | 43 ++++++++++++++++++++++++++++++++-----------
include/linux/blkdev.h | 2 ++
include/linux/genhd.h | 1 +
3 files changed, 35 insertions(+), 11 deletions(-)

Index: b/fs/partitions/check.c
===================================================================
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -556,28 +556,49 @@ int rescan_partitions(struct gendisk *di

/* add partitions */
for (p = 1; p < state->limit; p++) {
- sector_t size = state->parts[p].size;
- sector_t from = state->parts[p].from;
+ sector_t size, from;
+try_scan:
+ size = state->parts[p].size;
if (!size)
continue;
+
+ from = state->parts[p].from;
if (from >= get_capacity(disk)) {
printk(KERN_WARNING
"%s: p%d ignored, start %llu is behind the end of the disk\n",
disk->disk_name, p, (unsigned long long) from);
continue;
}
+
if (from + size > get_capacity(disk)) {
- /*
- * we can not ignore partitions of broken tables
- * created by for example camera firmware, but we
- * limit them to the end of the disk to avoid
- * creating invalid block devices
- */
+ struct block_device_operations *bdops = disk->fops;
+ unsigned long long capacity;
+
printk(KERN_WARNING
- "%s: p%d size %llu exceeds device capacity, "
- "limited to end of disk\n",
+ "%s: p%d size %llu exceeds device capacity, ",
disk->disk_name, p, (unsigned long long) size);
- size = get_capacity(disk) - from;
+
+ if (bdops->set_capacity &&
+ (disk->flags & GENHD_FL_NATIVE_CAPACITY) == 0) {
+ printk(KERN_CONT "enabling native capacity\n");
+ capacity = bdops->set_capacity(disk, ~0ULL);
+ disk->flags |= GENHD_FL_NATIVE_CAPACITY;
+ if (capacity > get_capacity(disk)) {
+ set_capacity(disk, capacity);
+ check_disk_size_change(disk, bdev);
+ bdev->bd_invalidated = 0;
+ }
+ goto try_scan;
+ } else {
+ /*
+ * we can not ignore partitions of broken tables
+ * created by for example camera firmware, but
+ * we limit them to the end of the disk to avoid
+ * creating invalid block devices
+ */
+ printk(KERN_CONT "limited to end of disk\n");
+ size = get_capacity(disk) - from;
+ }
}
part = add_partition(disk, p, from, size,
state->parts[p].flags);
Index: b/include/linux/blkdev.h
===================================================================
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1221,6 +1221,8 @@ struct block_device_operations {
int (*direct_access) (struct block_device *, sector_t,
void **, unsigned long *);
int (*media_changed) (struct gendisk *);
+ unsigned long long (*set_capacity) (struct gendisk *,
+ unsigned long long);
int (*revalidate_disk) (struct gendisk *);
int (*getgeo)(struct block_device *, struct hd_geometry *);
struct module *owner;
Index: b/include/linux/genhd.h
===================================================================
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -114,6 +114,7 @@ struct hd_struct {
#define GENHD_FL_UP 16
#define GENHD_FL_SUPPRESS_PARTITION_INFO 32
#define GENHD_FL_EXT_DEVT 64 /* allow extended devt */
+#define GENHD_FL_NATIVE_CAPACITY 128

#define BLK_SCSI_MAX_CMDS (256)
#define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))