path: root/image
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authorFilipe Manana <>2017-05-17 02:41:21 +0100
committerDavid Sterba <>2017-06-26 17:07:52 +0200
commit3a05074c167ceea8c49a902b383c307c0c61eec2 (patch)
tree2bd4fe18a03263f5e7c6314fbd91e49f6eb493c5 /image
parent8dcc1b6f6526638eeae0f3121deb1a630ad4a400 (diff)
btrfs-progs: Fix restoring image from multi devices fs into single device
We correctly build an image from a multiple devices filesystem but when restoring the image into a single device we were missing updating the number of devices in the superblock to the value 1 (we already took care of setting the number of stripes to 1 for each chunk item and setting the device id for each chunk item to match the device id from the super block). This missing update of the number of devices makes it impossible to mount the restored filesystem on recent kernels, more specifically since the linux kernel commit 99e3ecfcb9f4ca35192d20a5bea158b81f600062 ("Btrfs: add more validation checks for superblock"), that produce the following message in the dmesg/syslog: [21097.542047] BTRFS error (device sdi): super_num_devices 2 mismatch with num_devices 1 found here [21097.543972] BTRFS error (device sdi): failed to read chunk tree: -22 [21097.720360] BTRFS error (device sdi): open_ctree failed So fix this by updating the number of devices to 1 in the superblock. Signed-off-by: Filipe Manana <> Reviewed-by: Liu Bo <> Signed-off-by: David Sterba <>
Diffstat (limited to 'image')
1 files changed, 1 insertions, 0 deletions
diff --git a/image/main.c b/image/main.c
index f1c28de1..1eca414b 100644
--- a/image/main.c
+++ b/image/main.c
@@ -1500,6 +1500,7 @@ static int update_super(struct mdrestore_struct *mdres, u8 *buffer)
btrfs_set_super_flags(super, flags);
btrfs_set_super_sys_array_size(super, new_array_size);
+ btrfs_set_super_num_devices(super, 1);
csum_block(buffer, BTRFS_SUPER_INFO_SIZE);
return 0;