This is a note to let you know that I've just added the patch titled
dm: track per-add_disk holder relations in DM
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-track-per-add_disk-holder-relations-in-dm.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a55bcb965cbb8704e1aa6c6ddd7ebca9373a966a
Author: Christoph Hellwig <hch@xxxxxx>
Date: Tue Nov 15 22:10:50 2022 +0800
dm: track per-add_disk holder relations in DM
[ Upstream commit 1a581b72169968f4154b5793828f3bc28b258b35 ]
dm is a bit special in that it opens the underlying devices. Commit
89f871af1b26 ("dm: delay registering the gendisk") tried to accommodate
that by allowing to add the holder to the list before add_gendisk and
then just add them to sysfs once add_disk is called. But that leads to
really odd lifetime problems and error handling problems as we can't
know the state of the kobjects and don't unwind properly. To fix this
switch to just registering all existing table_devices with the holder
code right after add_disk, and remove them before calling del_gendisk.
Fixes: 89f871af1b26 ("dm: delay registering the gendisk")
Reported-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221115141054.1051801-7-yukuai1@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e7fc2a69633c..bbde744f7dba 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -751,9 +751,16 @@ static struct table_device *open_table_device(struct mapped_device *md,
goto out_free_td;
}
- r = bd_link_disk_holder(bdev, dm_disk(md));
- if (r)
- goto out_blkdev_put;
+ /*
+ * We can be called before the dm disk is added. In that case we can't
+ * register the holder relation here. It will be done once add_disk was
+ * called.
+ */
+ if (md->disk->slave_dir) {
+ r = bd_link_disk_holder(bdev, md->disk);
+ if (r)
+ goto out_blkdev_put;
+ }
td->dm_dev.mode = mode;
td->dm_dev.bdev = bdev;
@@ -774,7 +781,8 @@ static struct table_device *open_table_device(struct mapped_device *md,
*/
static void close_table_device(struct table_device *td, struct mapped_device *md)
{
- bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
+ if (md->disk->slave_dir)
+ bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
put_dax(td->dm_dev.dax_dev);
list_del(&td->list);
@@ -1964,7 +1972,13 @@ static void cleanup_mapped_device(struct mapped_device *md)
md->disk->private_data = NULL;
spin_unlock(&_minor_lock);
if (dm_get_md_type(md) != DM_TYPE_NONE) {
+ struct table_device *td;
+
dm_sysfs_exit(md);
+ list_for_each_entry(td, &md->table_devices, list) {
+ bd_unlink_disk_holder(td->dm_dev.bdev,
+ md->disk);
+ }
/*
* Hold lock to make sure del_gendisk() won't concurrent
@@ -2304,6 +2318,7 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
{
enum dm_queue_mode type = dm_table_get_type(t);
struct queue_limits limits;
+ struct table_device *td;
int r;
switch (type) {
@@ -2342,16 +2357,30 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
if (r)
return r;
- r = dm_sysfs_init(md);
- if (r) {
- mutex_lock(&md->table_devices_lock);
- del_gendisk(md->disk);
- mutex_unlock(&md->table_devices_lock);
- return r;
+ /*
+ * Register the holder relationship for devices added before the disk
+ * was live.
+ */
+ list_for_each_entry(td, &md->table_devices, list) {
+ r = bd_link_disk_holder(td->dm_dev.bdev, md->disk);
+ if (r)
+ goto out_undo_holders;
}
+ r = dm_sysfs_init(md);
+ if (r)
+ goto out_undo_holders;
+
md->type = type;
return 0;
+
+out_undo_holders:
+ list_for_each_entry_continue_reverse(td, &md->table_devices, list)
+ bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
+ mutex_lock(&md->table_devices_lock);
+ del_gendisk(md->disk);
+ mutex_unlock(&md->table_devices_lock);
+ return r;
}
struct mapped_device *dm_get_md(dev_t dev)
--
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