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Dave Jones |
43a44e9 |
Hi,
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
Thank you for review and comments.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
On 02/16/12 02:26, Tejun Heo wrote:
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Dave Jones |
43a44e9 |
> On Wed, Feb 15, 2012 at 11:56:19AM +0900, Jun'ichi Nomura wrote:
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Dave Jones |
43a44e9 |
>> +int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
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Dave Jones |
43a44e9 |
>> +{
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Dave Jones |
43a44e9 |
>> + int res;
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Dave Jones |
43a44e9 |
>> +
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Dave Jones |
43a44e9 |
>> + res = drop_partitions(disk, bdev);
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Dave Jones |
43a44e9 |
>> + if (res)
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Dave Jones |
43a44e9 |
>> + return res;
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Dave Jones |
43a44e9 |
>> +
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Dave Jones |
43a44e9 |
>
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Dave Jones |
43a44e9 |
> Hmmm... shouldn't we have set_capacity(disk, 0) here?
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
Added.
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Dave Jones |
43a44e9 |
I wasn't sure whether I should leave it to drivers.
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Dave Jones |
43a44e9 |
But it seems capacity 0 for ENOMEDIUM device is reasonable.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
>> + check_disk_size_change(disk, bdev);
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Dave Jones |
43a44e9 |
>> + bdev->bd_invalidated = 0;
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Dave Jones |
43a44e9 |
>> + /* tell userspace that the media / partition table may have changed */
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Dave Jones |
43a44e9 |
>> + kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
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Dave Jones |
43a44e9 |
>
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Dave Jones |
43a44e9 |
> Also, we really shouldn't be generating KOBJ_CHANGE after every
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Dave Jones |
43a44e9 |
> -ENOMEDIUM open. This can easily lead to infinite loop. We should
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Dave Jones |
43a44e9 |
> generate this iff we actually dropped partitions && modified the size.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
invalidate_partitions() is called only when bd_invalidated is set.
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Dave Jones |
43a44e9 |
So KOBJ_CHANGE is not raised for every ENOMEDIUM open.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
I put it explicit in the function to make it safer for
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Dave Jones |
43a44e9 |
possible misuse.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
How about this?
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
---------------------------------------------------------
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Dave Jones |
43a44e9 |
Do not call drivers when invalidating partitions for -ENOMEDIUM
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
When a scsi driver returns -ENOMEDIUM for open(),
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Dave Jones |
43a44e9 |
__blkdev_get() calls rescan_partitions(), which ends up calling
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Dave Jones |
43a44e9 |
sd_revalidate_disk() without getting a refcount of scsi_device.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
That could lead to oops like this:
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
process A process B
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Dave Jones |
43a44e9 |
----------------------------------------------
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Dave Jones |
43a44e9 |
sys_open
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Dave Jones |
43a44e9 |
__blkdev_get
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Dave Jones |
43a44e9 |
sd_open
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Dave Jones |
43a44e9 |
returns -ENOMEDIUM
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Dave Jones |
43a44e9 |
scsi_remove_device
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Dave Jones |
43a44e9 |
<scsi_device torn down>
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Dave Jones |
43a44e9 |
rescan_partitions
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Dave Jones |
43a44e9 |
sd_revalidate_disk
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Dave Jones |
43a44e9 |
<oops>
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
Oopses are reported here:
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Dave Jones |
43a44e9 |
http://marc.info/?l=linux-scsi&m=132388619710052
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
This patch separates the partition invalidation from rescan_partitions()
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Dave Jones |
43a44e9 |
and use it for -ENOMEDIUM case.
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
Index: linux-3.3/block/partition-generic.c
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Dave Jones |
43a44e9 |
===================================================================
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Dave Jones |
43a44e9 |
--- linux-3.3.orig/block/partition-generic.c 2012-02-15 09:00:25.147293790 +0900
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Dave Jones |
43a44e9 |
+++ linux-3.3/block/partition-generic.c 2012-02-16 10:48:22.257680685 +0900
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Dave Jones |
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@@ -389,17 +389,11 @@ static bool disk_unlock_native_capacity(
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Dave Jones |
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}
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Dave Jones |
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}
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Dave Jones |
43a44e9 |
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Dave Jones |
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-int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
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Dave Jones |
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+static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
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Dave Jones |
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{
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Dave Jones |
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- struct parsed_partitions *state = NULL;
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Dave Jones |
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struct disk_part_iter piter;
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Dave Jones |
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struct hd_struct *part;
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Dave Jones |
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- int p, highest, res;
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Dave Jones |
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-rescan:
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Dave Jones |
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- if (state && !IS_ERR(state)) {
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Dave Jones |
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- kfree(state);
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Dave Jones |
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- state = NULL;
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Dave Jones |
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- }
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Dave Jones |
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+ int res;
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Dave Jones |
43a44e9 |
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Dave Jones |
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if (bdev->bd_part_count)
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Dave Jones |
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return -EBUSY;
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Dave Jones |
43a44e9 |
@@ -412,6 +406,24 @@ rescan:
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Dave Jones |
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delete_partition(disk, part->partno);
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Dave Jones |
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disk_part_iter_exit(&piter);
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Dave Jones |
43a44e9 |
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Dave Jones |
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+ return 0;
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Dave Jones |
43a44e9 |
+}
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Dave Jones |
43a44e9 |
+
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Dave Jones |
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+int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
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Dave Jones |
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+{
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Dave Jones |
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+ struct parsed_partitions *state = NULL;
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Dave Jones |
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+ struct hd_struct *part;
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Dave Jones |
43a44e9 |
+ int p, highest, res;
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Dave Jones |
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+rescan:
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Dave Jones |
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+ if (state && !IS_ERR(state)) {
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Dave Jones |
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+ kfree(state);
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Dave Jones |
43a44e9 |
+ state = NULL;
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Dave Jones |
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+ }
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Dave Jones |
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+
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Dave Jones |
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+ res = drop_partitions(disk, bdev);
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Dave Jones |
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+ if (res)
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Dave Jones |
43a44e9 |
+ return res;
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Dave Jones |
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+
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Dave Jones |
43a44e9 |
if (disk->fops->revalidate_disk)
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Dave Jones |
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disk->fops->revalidate_disk(disk);
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Dave Jones |
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check_disk_size_change(disk, bdev);
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Dave Jones |
43a44e9 |
@@ -515,6 +527,26 @@ rescan:
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Dave Jones |
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return 0;
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Dave Jones |
43a44e9 |
}
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
+int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
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Dave Jones |
43a44e9 |
+{
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Dave Jones |
43a44e9 |
+ int res;
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Dave Jones |
43a44e9 |
+
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Dave Jones |
43a44e9 |
+ if (!bdev->bd_invalidated)
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Dave Jones |
43a44e9 |
+ return 0;
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Dave Jones |
43a44e9 |
+
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Dave Jones |
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+ res = drop_partitions(disk, bdev);
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Dave Jones |
43a44e9 |
+ if (res)
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Dave Jones |
43a44e9 |
+ return res;
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Dave Jones |
43a44e9 |
+
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Dave Jones |
43a44e9 |
+ set_capacity(disk, 0);
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Dave Jones |
43a44e9 |
+ check_disk_size_change(disk, bdev);
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Dave Jones |
43a44e9 |
+ bdev->bd_invalidated = 0;
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Dave Jones |
43a44e9 |
+ /* tell userspace that the media / partition table may have changed */
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Dave Jones |
43a44e9 |
+ kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
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Dave Jones |
43a44e9 |
+
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Dave Jones |
43a44e9 |
+ return 0;
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Dave Jones |
43a44e9 |
+}
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Dave Jones |
43a44e9 |
+
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Dave Jones |
43a44e9 |
unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
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Dave Jones |
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{
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Dave Jones |
43a44e9 |
struct address_space *mapping = bdev->bd_inode->i_mapping;
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Dave Jones |
43a44e9 |
Index: linux-3.3/include/linux/genhd.h
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Dave Jones |
43a44e9 |
===================================================================
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Dave Jones |
43a44e9 |
--- linux-3.3.orig/include/linux/genhd.h 2012-02-09 12:21:53.000000000 +0900
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Dave Jones |
43a44e9 |
+++ linux-3.3/include/linux/genhd.h 2012-02-16 10:47:43.783681813 +0900
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Dave Jones |
43a44e9 |
@@ -596,6 +596,7 @@ extern char *disk_name (struct gendisk *
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Dave Jones |
43a44e9 |
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Dave Jones |
43a44e9 |
extern int disk_expand_part_tbl(struct gendisk *disk, int target);
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Dave Jones |
43a44e9 |
extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
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Dave Jones |
43a44e9 |
+extern int invalidate_partitions(struct gendisk *disk, struct block_device *bdev);
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Dave Jones |
43a44e9 |
extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
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Dave Jones |
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int partno, sector_t start,
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Dave Jones |
43a44e9 |
sector_t len, int flags,
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Dave Jones |
43a44e9 |
Index: linux-3.3/fs/block_dev.c
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Dave Jones |
43a44e9 |
===================================================================
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Dave Jones |
43a44e9 |
--- linux-3.3.orig/fs/block_dev.c 2012-02-09 12:21:53.000000000 +0900
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Dave Jones |
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+++ linux-3.3/fs/block_dev.c 2012-02-16 10:47:52.602681441 +0900
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Dave Jones |
43a44e9 |
@@ -1183,8 +1183,12 @@ static int __blkdev_get(struct block_dev
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Dave Jones |
43a44e9 |
* The latter is necessary to prevent ghost
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Dave Jones |
43a44e9 |
* partitions on a removed medium.
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Dave Jones |
43a44e9 |
*/
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Dave Jones |
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- if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
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Dave Jones |
43a44e9 |
- rescan_partitions(disk, bdev);
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Dave Jones |
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+ if (bdev->bd_invalidated) {
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Dave Jones |
43a44e9 |
+ if (!ret)
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Dave Jones |
43a44e9 |
+ rescan_partitions(disk, bdev);
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Dave Jones |
43a44e9 |
+ else if (ret == -ENOMEDIUM)
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Dave Jones |
43a44e9 |
+ invalidate_partitions(disk, bdev);
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Dave Jones |
43a44e9 |
+ }
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Dave Jones |
43a44e9 |
if (ret)
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Dave Jones |
43a44e9 |
goto out_clear;
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Dave Jones |
43a44e9 |
} else {
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Dave Jones |
43a44e9 |
@@ -1214,8 +1218,12 @@ static int __blkdev_get(struct block_dev
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Dave Jones |
43a44e9 |
if (bdev->bd_disk->fops->open)
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Dave Jones |
43a44e9 |
ret = bdev->bd_disk->fops->open(bdev, mode);
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Dave Jones |
43a44e9 |
/* the same as first opener case, read comment there */
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Dave Jones |
43a44e9 |
- if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
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Dave Jones |
43a44e9 |
- rescan_partitions(bdev->bd_disk, bdev);
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Dave Jones |
43a44e9 |
+ if (bdev->bd_invalidated) {
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Dave Jones |
43a44e9 |
+ if (!ret)
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Dave Jones |
43a44e9 |
+ rescan_partitions(bdev->bd_disk, bdev);
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Dave Jones |
43a44e9 |
+ else if (ret == -ENOMEDIUM)
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Dave Jones |
43a44e9 |
+ invalidate_partitions(bdev->bd_disk, bdev);
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Dave Jones |
43a44e9 |
+ }
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Dave Jones |
43a44e9 |
if (ret)
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Dave Jones |
43a44e9 |
goto out_unlock_bdev;
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Dave Jones |
43a44e9 |
}
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