When the old device has new fsid through btrfs device add -f <dev> our
fs_devices list has an alien device in one of the fs_devices.
By having an alien device in fs_devices, we have two issues so far
1. missing device is not shows as missing in the userland
Which is due to cracks in the function btrfs_open_one_device() and
hardened by patch
btrfs: delete identified alien device in open_fs_devices
2. mount of a degraded fs_devices fails
Which is due to cracks in the function btrfs_free_extra_devids() and
hardened by patch
btrfs: include non-missing as a qualifier for the latest_bdev
Now the reason for both of this issue is that there is an alien (does not
contain the intended fsid) device in the fs_devices.
We know a device can be scanned/added through
btrfs-control::BTRFS_IOC_SCAN_DEV|BTRFS_IOC_DEVICES_READY
or by
ioctl::BTRFS_IOC_ADD_DEV
And device coming through btrfs-control is checked against the all other
devices in btrfs kernel but not coming through BTRFS_IOC_ADD_DEV.
This patch checks if the device add is alienating any other scanned
device and deletes it.
In fact, this patch fixes both the issues 1 and 2 (above) by eliminating
the source of the issue, but still they have their own patch as well
because its the right way to harden the functions and fill the cracks.
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
fs/btrfs/volumes.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 6c42048ec099..f8b21e82df2a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2736,6 +2736,19 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info,
const char *device_path
/* Update ctime/mtime for libblkid */
update_dev_time(device_path);
+
+ /*
+ * Now that we have written a new sb into this device, check all other
+ * fs_devices list if it alienates any scanned device.
+ */
+ mutex_lock(&uuid_mutex);
+ /*
+ * Ignore the return as we are successfull in the core task - to added
+ * the device
+ */
+ btrfs_free_stale_devices(device_path, NULL);
+ mutex_unlock(&uuid_mutex);
+
return ret;
error_sysfs:
--
1.8.3.1
