When we mount a btrfs filesystem from read-only media there will be no read/write devices; for example mounting an SD card with its lock enabled. This triggers an immediate BUG during mount:
kernel BUG at .../fs/btrfs/super.c:984! This is triggered by statfs when calculating the free space in the filesytem. We bug if the number of read/write devices is 0. This check seems spurious as the information collected is valid regardless of whether the devices are read-only or not. As the count is used to size the sort array it seems more correct to switch it to the number of open devices. BugLink: http://bugs.launchpad.net/bugs/816770 Signed-off-by: Andy Whitcroft <[email protected]> --- fs/btrfs/super.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 15634d4..ae4367a 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -980,7 +980,7 @@ 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); devices_info = kmalloc(sizeof(*devices_info) * nr_devices, -- 1.7.4.1 -- 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
