In open_fs_devices() we identify alien device but we don't reset its
the device::name. So progs device list does not show the device missing
as shown in the script below.
mkfs.btrfs -fq /dev/sdd && mount /dev/sdd /btrfs
mkfs.btrfs -fq -draid1 -mraid1 /dev/sdc /dev/sdb
sleep 3 # avoid racing with udev's useless scans if needed
btrfs dev add -f /dev/sdb /btrfs
mount -o degraded /dev/sdc /btrfs1
No missing device:
btrfs fi show -m /btrfs1
Label: none uuid: 3eb7cd50-4594-458f-9d68-c243cc49954d
Total devices 2 FS bytes used 128.00KiB
devid 1 size 12.00GiB used 1.26GiB path /dev/sdc
devid 2 size 12.00GiB used 1.26GiB path /dev/sdb
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
PS: Fundamentally its wrong approach that btrfs-progs deduces the device
missing state in the userland instead of obtaining it from the kernel.
I objected on the patch, but still those patches got merged, this bug is
one of its side effects. Ironically I wrote patches to read device_state
from the kernel using ioctl, procfs and sysfs but didn't get the due
attention till a merger.
fs/btrfs/volumes.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 06ec3577c6b4..05ade8c7342b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -803,10 +803,10 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices,
disk_super = (struct btrfs_super_block *)bh->b_data;
devid = btrfs_stack_device_id(&disk_super->dev_item);
if (devid != device->devid)
- goto error_brelse;
+ goto free_alien;
if (memcmp(device->uuid, disk_super->dev_item.uuid, BTRFS_UUID_SIZE))
- goto error_brelse;
+ goto free_alien;
device->generation = btrfs_super_generation(disk_super);
@@ -845,6 +845,11 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices,
return 0;
+free_alien:
+ fs_devices->num_devices--;
+ list_del(&device->dev_list);
+ btrfs_free_device(device);
+
error_brelse:
brelse(bh);
blkdev_put(bdev, flags);
@@ -1329,11 +1334,13 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices,
fmode_t flags, void *holder)
{
struct btrfs_device *device;
+ struct btrfs_device *tmp_device;
struct btrfs_device *latest_dev = NULL;
flags |= FMODE_EXCL;
- list_for_each_entry(device, &fs_devices->devices, dev_list) {
+ list_for_each_entry_safe(device, tmp_device, &fs_devices->devices,
+ dev_list) {
/* Just open everything we can; ignore failures here */
if (btrfs_open_one_device(fs_devices, device, flags, holder))
continue;
--
1.8.3.1
