On Mon, Nov 28, 2011 at 04:43:00PM +0800, Li Zefan wrote: > To reproduce this bug: > > # dd if=/dev/zero of=img bs=1M count=256 > # mkfs.btrfs img > # losetup -r /dev/loop1 img > # mount /dev/loop1 /mnt > OOPS!! > > It triggered BUG_ON(!nr_devices) in btrfs_calc_avail_data_space().
FYI, A patch fixing this has been sent long ago but the was not picked up. I have collected and pushed it to Chris last week. http://lkml.indiana.edu/hypermail/linux/kernel/1108.0/00157.html > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -1083,7 +1083,7 @@ static int btrfs_calc_avail_data_space(struct > btrfs_root *root, u64 *free_bytes) > int i = 0, nr_devices; > int ret; > > - nr_devices = fs_info->fs_devices->rw_devices; > + nr_devices = fs_info->fs_devices->open_devices; > BUG_ON(!nr_devices); This what the referenced patch does ... > > devices_info = kmalloc(sizeof(*devices_info) * nr_devices, > @@ -1105,8 +1105,8 @@ static int btrfs_calc_avail_data_space(struct > btrfs_root *root, u64 *free_bytes) > else > min_stripe_size = BTRFS_STRIPE_LEN; > > - list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) { > - if (!device->in_fs_metadata) > + list_for_each_entry(device, &fs_devices->devices, dev_list) { > + if (!device->in_fs_metadata || !device->bdev) > continue; ... but misses this part, so you patch is more complete and should be picked instead. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
