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>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Emphatically-Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 137a708bb21527f7fa3c139a1177fec3d2ca4d8d..4bc2c43fa0839f6493ab6a0de7ec2638d577f8dc 100644 (file)
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -546,28 +546,49 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 
        /* 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);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6f841fb1be3041aae3241aa73e48667992565a56..a2d7298be351211b5ca6fdb8f650458044a39d0f 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1106,6 +1106,8 @@ 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;

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 634c53028fb81da1fd2a211acb291101bdfff01f..239e24b081a9a959f2689b8bc824e44713c3ec3f 100644 (file)
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -113,6 +113,7 @@ 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))