Support for a new command is being added here:
btrfs dev ignore <dev>
Which shall undo the effects of the command
btrfs dev scan <dev>
This cli/ioctl is needed as there is no way to continue to mount in
degraded mode if the device is already scanned, which is required to
recover from the split brain raid conditions.
This patch proposes to use ioctl #5 as it was empty.
IOW(BTRFS_IOCTL_MAGIC, 5, ..)
If #5 is reserved for some other purpose, I think I should change this.
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
fs/btrfs/super.c | 4 +++
fs/btrfs/volumes.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/volumes.h | 2 ++
include/uapi/linux/btrfs.h | 2 ++
4 files changed, 78 insertions(+)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index fa7bad8b22da..64f4beb1526d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2183,6 +2183,10 @@ static long btrfs_control_ioctl(struct file *file,
unsigned int cmd,
ret = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_fs_type, &fs_devices);
break;
+ case BTRFS_IOC_IGNORE_DEV:
+ ret = btrfs_ignore_one_device(vol->name, FMODE_READ,
+ &btrfs_fs_type, &fs_devices);
+ break;
case BTRFS_IOC_DEVICES_READY:
ret = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_fs_type, &fs_devices);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8ead85dba6f5..1a06a17e111e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1181,6 +1181,76 @@ int btrfs_read_disk_super(struct block_device *bdev, u64
bytenr,
return 0;
}
+static int device_list_remove(struct btrfs_super_block *disk_super, u64 devid)
+{
+ int ret = 0;
+ struct btrfs_fs_devices *fs_devices;
+ struct btrfs_device *device;
+
+ fs_devices = find_fsid(disk_super->fsid);
+ if (!fs_devices)
+ return -ENOENT;
+
+ if (fs_devices->opened)
+ return -EPERM;
+
+ mutex_lock(&uuid_mutex);
+ mutex_lock(&fs_devices->device_list_mutex);
+ device = find_device(fs_devices, devid, disk_super->dev_item.uuid);
+ if (!device) {
+ ret = -ENOENT;
+ goto error;
+ }
+
+ delete_device_from_list(device);
+
+error:
+ mutex_unlock(&fs_devices->device_list_mutex);
+ mutex_unlock(&uuid_mutex);
+
+ return ret;
+}
+
+int btrfs_ignore_one_device(const char *path, fmode_t flags, void *holder,
+ struct btrfs_fs_devices **fs_devices_ret)
+{
+ struct btrfs_super_block *disk_super;
+ struct block_device *bdev;
+ struct page *page;
+ int ret = -EINVAL;
+ u64 devid;
+ u64 bytenr;
+
+ bytenr = btrfs_sb_offset(0);
+ flags |= FMODE_EXCL;
+
+ bdev = blkdev_get_by_path(path, flags, holder);
+ if (IS_ERR(bdev)) {
+ ret = PTR_ERR(bdev);
+ goto error;
+ }
+
+ if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super))
+ goto error_bdev_put;
+
+ devid = btrfs_stack_device_id(&disk_super->dev_item);
+
+ ret = device_list_remove(disk_super, devid);
+ if (ret)
+ pr_err("BTRFS: %pU: device %s uuid %pU devid %llu failed to unscan: %d",
+ disk_super->fsid, path, disk_super->dev_item.uuid, devid, ret);
+ else
+ pr_info("BTRFS: %pU: device %s uuid %pU devid %llu ran undo scan",
+ disk_super->fsid, path, disk_super->dev_item.uuid, devid);
