From cb37bf83cc583dfe1e22344049a649b363228509 Mon Sep 17 00:00:00 2001 From: Gui Hecheng Date: Mon, 6 Oct 2014 18:17:49 +0800 Subject: btrfs-progs: fix BUG_ON when all devices under seed fs are missing 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 Signed-off-by: David Sterba --- volumes.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'volumes.c') diff --git a/volumes.c b/volumes.c index 009ce785..b47bce6b 100644 --- a/volumes.c +++ b/volumes.c @@ -1672,8 +1672,15 @@ 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); -- cgit v1.2.3