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authorPhilipp Reisner <philipp.reisner@linbit.com>2013-11-22 13:22:13 +0100
committerPhilipp Reisner <philipp.reisner@linbit.com>2014-07-10 15:22:20 +0200
commit8fe39aac0578cbb0abf27e1be70ff581e0c1d836 (patch)
tree3a3f8c724dec46a06ecf2d490905a3f6fbd80045 /drivers/block/drbd/drbd_bitmap.c
parente952658020c5150ad4987d313e25e8e2fb38d529 (diff)
downloadlinux-8fe39aac0578cbb0abf27e1be70ff581e0c1d836.tar.gz
linux-8fe39aac0578cbb0abf27e1be70ff581e0c1d836.tar.xz
drbd: device->ldev is not guaranteed on an D_ATTACHING disk
Some parts of the code assumed that get_ldev_if_state(device, D_ATTACHING) is sufficient to access the ldev member of the device object. That was wrong. ldev may not be there or might be freed at any time if the device has a disk state of D_ATTACHING. bm_rw() Documented that drbd_bm_read() is only called from drbd_adm_attach. drbd_bm_write() is only called when a reference is held, and it is documented that a caller has to hold a reference before calling drbd_bm_write() drbd_bm_write_page() Use get_ldev() instead of get_ldev_if_state(device, D_ATTACHING) drbd_bmio_set_n_write() No longer use get_ldev_if_state(device, D_ATTACHING). All callers hold a reference to ldev now. drbd_bmio_clear_n_write() All callers where holding a reference of ldev anyways. Remove the misleading get_ldev_if_state(device, D_ATTACHING) drbd_reconsider_max_bio_size() Removed the get_ldev_if_state(device, D_ATTACHING). All callers now pass a struct drbd_backing_dev* when they have a proper reference, or a NULL pointer. Before this fix, the receiver could trigger a NULL pointer deref when in drbd_reconsider_max_bio_size() drbd_bump_write_ordering() Used get_ldev_if_state(device, D_ATTACHING) with the wrong assumption. Remove it, and allow the caller to pass in a struct drbd_backing_dev* when the caller knows that accessing this bdev is safe. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd/drbd_bitmap.c')
-rw-r--r--drivers/block/drbd/drbd_bitmap.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 1aa29f8fdfe1..ed310415020b 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -1085,6 +1085,8 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
kfree(ctx);
return -ENODEV;
}
+ /* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from
+ drbd_adm_attach(), after device->ldev was assigned. */
if (!ctx->flags)
WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));
@@ -1260,7 +1262,7 @@ int drbd_bm_write_page(struct drbd_device *device, unsigned int idx) __must_hold
.kref = { ATOMIC_INIT(2) },
};
- if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in bm_aio_ctx_destroy() */
+ if (!get_ldev(device)) { /* put is in bm_aio_ctx_destroy() */
drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in drbd_bm_write_page()\n");
kfree(ctx);
return -ENODEV;