Since commit 88c14590cdd6 ("btrfs: use RCU in btrfs_show_devname for
device list traversal") btrfs_show_devname no longer takes
device_list_mutex. As such the deadlock that 0ccd05285e7f ("btrfs: fix
a possible umount deadlock") aimed to fix no longer exists. So remove
the extra code that commit added.
This reverts commit 0ccd05285e7f5a8e297e1d6dfc41e7c65757d6fa.
Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
---
V2:
* Fixed build failure due to using old name of free_device_rcu function.
fs/btrfs/volumes.c | 26 ++++++--------------------
1 file changed, 6 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5bd6f3a40f9c..011a19b7930f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1004,7 +1004,7 @@ static void btrfs_close_bdev(struct btrfs_device *device)
blkdev_put(device->bdev, device->mode);
}
-static void btrfs_prepare_close_one_device(struct btrfs_device *device)
+static void btrfs_close_one_device(struct btrfs_device *device)
{
struct btrfs_fs_devices *fs_devices = device->fs_devices;
struct btrfs_device *new_device;
@@ -1022,6 +1022,8 @@ static void btrfs_prepare_close_one_device(struct btrfs_device *device)
if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
fs_devices->missing_devices--;
+ btrfs_close_bdev(device);
+
new_device = btrfs_alloc_device(NULL, &device->devid,
device->uuid);
BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
@@ -1035,39 +1037,23 @@ static void btrfs_prepare_close_one_device(struct btrfs_device *device)
list_replace_rcu(&device->dev_list, &new_device->dev_list);
new_device->fs_devices = device->fs_devices;
+
+ call_rcu(&device->rcu, free_device_rcu);
}
static int close_fs_devices(struct btrfs_fs_devices *fs_devices)
{
struct btrfs_device *device, *tmp;
- struct list_head pending_put;
-
- INIT_LIST_HEAD(&pending_put);
if (--fs_devices->opened > 0)
return 0;
mutex_lock(&fs_devices->device_list_mutex);
list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
- btrfs_prepare_close_one_device(device);
- list_add(&device->dev_list, &pending_put);
+ btrfs_close_one_device(device);
}
mutex_unlock(&fs_devices->device_list_mutex);
- /*
- * btrfs_show_devname() is using the device_list_mutex,
- * sometimes call to blkdev_put() leads vfs calling
- * into this func. So do put outside of device_list_mutex,
- * as of now.
- */
- while (!list_empty(&pending_put)) {
- device = list_first_entry(&pending_put,
- struct btrfs_device, dev_list);
- list_del(&device->dev_list);
- btrfs_close_bdev(device);
- call_rcu(&device->rcu, free_device_rcu);
- }
-
WARN_ON(fs_devices->open_devices);
WARN_ON(fs_devices->rw_devices);
fs_devices->opened = 0;
--
2.7.4
--
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