From 87fa3bb0786f37dff0b92f2c38421dd56d8902a9 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Tue, 29 Jul 2014 19:09:39 +0800 Subject: [PATCH] Btrfs: fix regression of btrfs device replace Commit 49c6f736f34f901117c20960ebd7d5e60f12fcac( btrfs: dev replace should replace the sysfs entry) added the missing sysfs entry in the process of device replace, but didn't take missing devices into account, so now we have BUG: unable to handle kernel NULL pointer dereference at 0000000000000088 IP: [] btrfs_kobj_rm_device+0x21/0x40 [btrfs] ... To reproduce it, 1. mkfs.btrfs -f disk1 disk2 2. mkfs.ext4 disk1 3. mount disk2 /mnt -odegraded 4. btrfs replace start -B 1 disk3 /mnt -------------------------- This fixes the problem. Reported-by: Chris Murphy Signed-off-by: Liu Bo Reviewed-by: Satoru Takeuchi Tested-by: Satoru Takeuchi Signed-off-by: Chris Mason --- fs/btrfs/sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 78699364f537..12e53556e214 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -614,7 +614,7 @@ int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info, if (!fs_info->device_dir_kobj) return -EINVAL; - if (one_device) { + if (one_device && one_device->bdev) { disk = one_device->bdev->bd_part; disk_kobj = &part_to_dev(disk)->kobj; -- 2.20.1