Hi,
Thank you for the comments.
On 02/15/12 01:28, Tejun Heo wrote:
>> that could lead to oops like this:
>>
>> process A process B
>> ----------------------------------------------
>> sys_open
>> __blkdev_get
>> sd_open
>> returns -ENOMEDIUM
>> scsi_remove_device
>> <scsi_device torn down>
>> rescan_partitions
>> sd_revalidate_disk
>> <oops>
>>
>> Should "revalidate_disk" of block_device_operations work
>> without successful open()?
>>
>> If so, sd_revalidate_disk() (and possibly other drivers) needs to be
>> fixed. (e.g. use scsi_disk_get/put by itself)
>>
>> If not, __blkdev_get() or rescan_partision() should avoid calling
>> "revalidate_disk" for -ENOMEDIUM case.
>
> Hmmm... right, that's a problem. Missed rescan_partitions() calling
> into driver. What we should probably do is separating out
> invalidation & partition shoot down into a separate function, say
> trucate_disk(), and call that on -ENOMEDIUM instead of
> rescan_partitions(). All that's necessary is killing the partition
> devices (and maybe zapping device size to zero). Any one interested
> in trying it?
How about this?
If the patch looks ok, I appreciate if somebody with removable media
could test the followings:
- the oops in sd_revalidate_disk() should not occur:
http://marc.info/?l=linux-scsi&m=132388619710052
- the problem reported here should not be re-introduced:
https://bugzilla.kernel.org/show_bug.cgi?id=13029
Index: linux-3.3/block/partition-generic.c
===================================================================
--- linux-3.3.orig/block/partition-generic.c 2012-02-15 09:00:25.147293790 +0900
+++ linux-3.3/block/partition-generic.c 2012-02-15 11:31:33.835554974 +0900
@@ -389,17 +389,11 @@ static bool disk_unlock_native_capacity(
}
}
-int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
+static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
{
- struct parsed_partitions *state = NULL;
struct disk_part_iter piter;
struct hd_struct *part;
- int p, highest, res;
-rescan:
- if (state && !IS_ERR(state)) {
- kfree(state);
- state = NULL;
- }
+ int res;
if (bdev->bd_part_count)
return -EBUSY;
@@ -412,6 +406,24 @@ rescan:
delete_partition(disk, part->partno);
disk_part_iter_exit(&piter);
+ return 0;
+}
+
+int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+ struct parsed_partitions *state = NULL;
+ struct hd_struct *part;
+ int p, highest, res;
+rescan:
+ if (state && !IS_ERR(state)) {
+ kfree(state);
+ state = NULL;
+ }
+
+ res = drop_partitions(disk, bdev);
+ if (res)
+ return res;
+
if (disk->fops->revalidate_disk)
disk->fops->revalidate_disk(disk);
check_disk_size_change(disk, bdev);
@@ -515,6 +527,22 @@ rescan:
return 0;
}
+int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+ int res;
+
+ res = drop_partitions(disk, bdev);
+ if (res)
+ return res;
+
+ check_disk_size_change(disk, bdev);
+ bdev->bd_invalidated = 0;
+ /* tell userspace that the media / partition table may have changed */
+ kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+
+ return 0;
+}
+
unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
{
struct address_space *mapping = bdev->bd_inode->i_mapping;
Index: linux-3.3/include/linux/genhd.h
===================================================================
--- linux-3.3.orig/include/linux/genhd.h 2012-02-09 12:21:53.000000000 +0900
+++ linux-3.3/include/linux/genhd.h 2012-02-15 11:18:59.661594629 +0900
@@ -596,6 +596,7 @@ extern char *disk_name (struct gendisk *
extern int disk_expand_part_tbl(struct gendisk *disk, int target);
extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
+extern int invalidate_partitions(struct gendisk *disk, struct block_device *bdev);
extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
int partno, sector_t start,
sector_t len, int flags,
Index: linux-3.3/fs/block_dev.c
===================================================================
--- linux-3.3.orig/fs/block_dev.c 2012-02-09 12:21:53.000000000 +0900
+++ linux-3.3/fs/block_dev.c 2012-02-15 11:34:48.800549266 +0900
@@ -1183,8 +1183,12 @@ static int __blkdev_get(struct block_dev
* The latter is necessary to prevent ghost
* partitions on a removed medium.
*/
- if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
- rescan_partitions(disk, bdev);
+ if (bdev->bd_invalidated) {
+ if (!ret)
+ rescan_partitions(disk, bdev);
+ else if (ret == -ENOMEDIUM)
+ invalidate_partitions(disk, bdev);
+ }
if (ret)
goto out_clear;
} else {
@@ -1214,8 +1218,12 @@ static int __blkdev_get(struct block_dev
if (bdev->bd_disk->fops->open)
ret = bdev->bd_disk->fops->open(bdev, mode);
/* the same as first opener case, read comment there */
- if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
- rescan_partitions(bdev->bd_disk, bdev);
+ if (bdev->bd_invalidated) {
+ if (!ret)
+ rescan_partitions(bdev->bd_disk, bdev);
+ else if (ret == -ENOMEDIUM)
+ invalidate_partitions(bdev->bd_disk, bdev);
+ }
if (ret)
goto out_unlock_bdev;
}
--
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