It turns out we don't properly rollback in-core btrfs_device state on
umount. We zero out ->bdev, ->in_fs_metadata and that's about it. In
particular, we don't zero out ->generation, and this can lead to us
refusing a mount -- a non-NULL fs_devices->latest_bdev is essential, but
btrfs_close_extra_devices will happily assign NULL to ->latest_bdev if
the first device on the dev_list happens to be missing and consequently
has no bdev attached. This happens because since commit a6b0d5c8
btrfs_close_extra_devices adjusts ->latest_bdev, and in doing that,
relies on the ->generation. Fix this, and possibly other problems, by
zeroing out everything except for what device_list_add sets, so that a
mount right after insmod and 'btrfs dev scan' is no different from any
later mount in this respect.
Signed-off-by: Ilya Dryomov <idryo...@gmail.com>
---
fs/btrfs/volumes.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index af17b17..2f6bc12 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -673,22 +673,19 @@ static int __btrfs_close_devices(struct btrfs_fs_devices
*fs_devices)
if (device->can_discard)
fs_devices->num_can_discard--;
- new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
- BUG_ON(!new_device); /* -ENOMEM */
- memcpy(new_device, device, sizeof(*new_device));
+ new_device = btrfs_alloc_device(NULL, &device->devid,
+ device->uuid);
+ BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
/* Safe because we are under uuid_mutex */
if (device->name) {
name = rcu_string_strdup(device->name->str, GFP_NOFS);
- BUG_ON(device->name && !name); /* -ENOMEM */
+ BUG_ON(!name); /* -ENOMEM */
rcu_assign_pointer(new_device->name, name);
}
- new_device->bdev = NULL;
- new_device->writeable = 0;
- new_device->in_fs_metadata = 0;
- new_device->can_discard = 0;
- spin_lock_init(&new_device->io_lock);
+
list_replace_rcu(&device->dev_list, &new_device->dev_list);
+ new_device->fs_devices = device->fs_devices;
call_rcu(&device->rcu, free_device);
}
--
1.7.10.4
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