On 13/11/19 6:27 PM, Johannes Thumshirn wrote:
Gracefully handle allocation failures in btrfs_close_one_device()'s
rcu_string_strdup() instead of crashing the machine.
Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
fs/btrfs/volumes.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0a2a73907563..e5864ca3bb3b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1064,7 +1064,7 @@ static void btrfs_close_bdev(struct btrfs_device *device)
static int btrfs_close_one_device(struct btrfs_device *device)
{
struct btrfs_fs_devices *fs_devices = device->fs_devices;
- struct btrfs_device *new_device;
+ struct btrfs_device *new_device = NULL;
struct rcu_string *name;
new_device = btrfs_alloc_device(NULL, &device->devid,
@@ -1072,6 +1072,15 @@ static int btrfs_close_one_device(struct btrfs_device *device)
if (IS_ERR(new_device))
goto err_close_device;
+ /* Safe because we are under uuid_mutex */
+ if (device->name) {
+ name = rcu_string_strdup(device->name->str, GFP_NOFS);
+ if (!name)
+ goto err_free_device;
+
+ rcu_assign_pointer(new_device->name, name);
+ }
+
Any idea why do we need to strdup() at all to close a device?
Thanks, Anand
if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
device->devid != BTRFS_DEV_REPLACE_DEVID) {
list_del_init(&device->dev_alloc_list);
@@ -1085,13 +1094,6 @@ static int btrfs_close_one_device(struct btrfs_device *device)
if (device->bdev)
fs_devices->open_devices--;
- /* Safe because we are under uuid_mutex */
- if (device->name) {
- name = rcu_string_strdup(device->name->str, GFP_NOFS);
- BUG_ON(!name); /* -ENOMEM */
- rcu_assign_pointer(new_device->name, name);
- }
-
list_replace_rcu(&device->dev_list, &new_device->dev_list);
new_device->fs_devices = device->fs_devices;
@@ -1100,6 +1102,10 @@ static int btrfs_close_one_device(struct btrfs_device *device)
return 0;
+err_free_device:
+ if (new_device)
+ btrfs_free_device(new_device);
+
err_close_device:
btrfs_close_bdev(device);
if (device->bdev) {
