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authorAnand Jain <Anand.Jain@oracle.com>2015-06-17 21:10:48 +0800
committerDavid Sterba <dsterba@suse.cz>2015-06-19 14:03:13 +0200
commit4fde46f0cc71c7aba299ee6dfb4f017fb97b6e70 (patch)
tree31a47f030f88140fa99e8fc555a942435db3a0fd /fs/btrfs
parent2421a8cd5faaa9c2c9397123c5a297bab227d965 (diff)
Btrfs: free the stale device
When btrfs on a device is overwritten with a new btrfs (mkfs), the old btrfs instance in the kernel becomes stale. So with this patch, if kernel finds device is overwritten then delete the stale fsid/uuid. Signed-off-by: Anand Jain <anand.jain@oracle.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/volumes.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b851964b7345..ea293db89cc4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -445,6 +445,61 @@ static void pending_bios_fn(struct btrfs_work *work)
run_scheduled_bios(device);
}
+
+void btrfs_free_stale_device(struct btrfs_device *cur_dev)
+{
+ struct btrfs_fs_devices *fs_devs;
+ struct btrfs_device *dev;
+
+ if (!cur_dev->name)
+ return;
+
+ list_for_each_entry(fs_devs, &fs_uuids, list) {
+ int del = 1;
+
+ if (fs_devs->opened)
+ continue;
+ if (fs_devs->seeding)
+ continue;
+
+ list_for_each_entry(dev, &fs_devs->devices, dev_list) {
+
+ if (dev == cur_dev)
+ continue;
+ if (!dev->name)
+ continue;
+
+ /*
+ * Todo: This won't be enough. What if the same device
+ * comes back (with new uuid and) with its mapper path?
+ * But for now, this does help as mostly an admin will
+ * either use mapper or non mapper path throughout.
+ */
+ rcu_read_lock();
+ del = strcmp(rcu_str_deref(dev->name),
+ rcu_str_deref(cur_dev->name));
+ rcu_read_unlock();
+ if (!del)
+ break;
+ }
+
+ if (!del) {
+ /* delete the stale device */
+ if (fs_devs->num_devices == 1) {
+ btrfs_sysfs_remove_fsid(fs_devs);
+ list_del(&fs_devs->list);
+ free_fs_devices(fs_devs);
+ } else {
+ fs_devs->num_devices--;
+ list_del(&dev->dev_list);
+ rcu_string_free(dev->name);
+ kfree(dev);
+ }
+ break;
+ }
+ }
+}
+
/*
* Add new device to list of registered devices
*
@@ -560,6 +615,12 @@ static noinline int device_list_add(const char *path,
if (!fs_devices->opened)
device->generation = found_transid;
+ /*
+ * if there is new btrfs on an already registered device,
+ * then remove the stale device entry.
+ */
+ btrfs_free_stale_device(device);
+
*fs_devices_ret = fs_devices;
return ret;