Steps to reproduce:
# mkfs.btrfs -f /dev/sda[1-2]
# btrfstune -S 1 /dev/sda1
# mount /dev/sda /mnt
# btrfs dev add /dev/sda3 /mnt
# umount /mnt
# mkfs.ext4 /dev/sda1 // kill seed dev
# mkfs.ext4 /dev/sda2 // kill seed dev
# btrfs-debug-tree /dev/sda3 <== BUG_ON
Output msg:
volumes.c:1824: btrfs_read_chunk_tree: Assertion `ret` failed.
btrfs-debug-tree[0x41cb36]
btrfs-debug-tree(btrfs_read_chunk_tree+0x3ca)
btrfs-debug-tree(btrfs_setup_chunk_tree_and_device_map
btrfs-debug-tree[0x40f695]
btrfs-debug-tree(open_ctree_fs_info+0x86)
btrfs-debug-tree(main+0x12d)
/lib64/libc.so.6(__libc_start_main+0xf5)
btrfs-debug-tree[0x4062e9]
This BUG_ON complains about a failed @read_one_dev() call when
@open_seed_devices() failed to find the seed @fs_devices object
for a dev_item in chunk tree.
In this case, just insert a "shadow" @fs_devices with the fsid in
dev_item shall make no harm since no other tools will try to
make use of the stuff that the "shadow" @fs_devices possesses
after its creation.
After apply this commit, btrfs-debug-tree will report unable
to open the device.
Signed-off-by: Gui Hecheng <guihc.f...@cn.fujitsu.com>
---
*Note*
This should be after patch:
Btrfs-progs: fsck: disallow partial opening if critical \
roots corrupted
---
volumes.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/volumes.c b/volumes.c
index eaf3f9f..a9c7662 100644
--- a/volumes.c
+++ b/volumes.c
@@ -1671,8 +1671,15 @@ static int open_seed_devices(struct btrfs_root *root, u8
*fsid)
fs_devices = find_fsid(fsid);
if (!fs_devices) {
- ret = -ENOENT;
- goto out;
+ /* missing all seed devices */
+ fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
+ if (!fs_devices) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ INIT_LIST_HEAD(&fs_devices->devices);
+ list_add(&fs_devices->list, &fs_uuids);
+ memcpy(fs_devices->fsid, fsid, BTRFS_FSID_SIZE);
}
ret = btrfs_open_devices(fs_devices, O_RDONLY);
--
1.8.1.4
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