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Subject[PATCH 06/18] drbd: fix drbd_delete_device: remove vnr from volumes; idr_remove(); synchronize_rcu(); before cleanup
Date
From: Lars Ellenberg <lars.ellenberg@linbit.com>

Still missing: rcu_readlock() on the various call sites that
access/iterate over those idrs.

We don't need a specific write lock, as we only modify from
configuration context, which is already strictly serialized.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
drivers/block/drbd/drbd_main.c | 42 ++++++++++++++++++++++-----------------
1 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 26bcd13..21914f4 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2124,7 +2124,9 @@ void drbd_delete_device(unsigned int minor)
if (!mdev)
return;

- idr_remove(&mdev->tconn->volumes, minor);
+ idr_remove(&mdev->tconn->volumes, mdev->vnr);
+ idr_remove(&minors, minor);
+ synchronize_rcu();

/* paranoia asserts */
D_ASSERT(mdev->open_cnt == 0);
@@ -2153,7 +2155,6 @@ void drbd_delete_device(unsigned int minor)
* allocated from drbd_new_device
* and actually free the mdev itself */
drbd_free_mdev(mdev);
- idr_remove(&minors, minor);
}

static void drbd_cleanup(void)
@@ -2331,15 +2332,6 @@ enum drbd_ret_code conn_new_minor(struct drbd_tconn *tconn, unsigned int minor,
return ERR_NOMEM;

mdev->tconn = tconn;
- if (!idr_pre_get(&tconn->volumes, GFP_KERNEL))
- goto out_no_idr;
- if (idr_get_new(&tconn->volumes, mdev, &vnr_got))
- goto out_no_idr;
- if (vnr_got != vnr) {
- dev_err(DEV, "vnr_got (%d) != vnr (%d)\n", vnr_got, vnr);
- goto out_no_q;
- }
-
mdev->minor = minor;

drbd_init_set_defaults(mdev);
@@ -2395,19 +2387,35 @@ enum drbd_ret_code conn_new_minor(struct drbd_tconn *tconn, unsigned int minor,
INIT_LIST_HEAD(&mdev->current_epoch->list);
mdev->epochs = 1;

+ if (!idr_pre_get(&tconn->volumes, GFP_KERNEL))
+ goto out_no_vol_idr;
+ if (idr_get_new(&tconn->volumes, mdev, &vnr_got))
+ goto out_no_vol_idr;
+ if (vnr_got != vnr) {
+ dev_err(DEV, "vnr_got (%d) != vnr (%d)\n", vnr_got, vnr);
+ goto out_idr_remove_vol;
+ }
+
if (!idr_pre_get(&minors, GFP_KERNEL))
- goto out_no_minor_idr;
+ goto out_idr_remove_vol;
if (idr_get_new(&minors, mdev, &minor_got))
- goto out_no_minor_idr;
+ goto out_idr_remove_vol;
if (minor_got != minor) {
- idr_remove(&minors, minor_got);
- goto out_no_minor_idr;
+ /* minor exists, or other idr strangeness? */
+ dev_err(DEV, "available minor (%d) != requested minor (%d)\n",
+ minor_got, minor);
+ goto out_idr_remove_minor;
}
add_disk(disk);

return NO_ERROR;

-out_no_minor_idr:
+out_idr_remove_minor:
+ idr_remove(&minors, minor_got);
+out_idr_remove_vol:
+ idr_remove(&tconn->volumes, vnr_got);
+ synchronize_rcu();
+out_no_vol_idr:
kfree(mdev->current_epoch);
out_no_epoch:
drbd_bm_cleanup(mdev);
@@ -2418,8 +2426,6 @@ out_no_io_page:
out_no_disk:
blk_cleanup_queue(q);
out_no_q:
- idr_remove(&tconn->volumes, vnr_got);
-out_no_idr:
kfree(mdev);
return ERR_NOMEM;
}
--
1.7.4.1


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