From b772a86ea6d932ac29d5e50e67c977653c832f8a Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 28 Nov 2011 16:43:00 +0800 Subject: [PATCH] Btrfs: fix oops when calling statfs on readonly device 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(). To fix this, instead of checking write-only devices, we check all open deivces: # df -h /dev/loop1 Filesystem Size Used Avail Use% Mounted on /dev/loop1 250M 28K 238M 1% /mnt Signed-off-by: Li Zefan --- fs/btrfs/super.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 8bd9d6d0e07a..1a3ce9e0b495 100644 --- 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); 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; avail_space = device->total_bytes - device->bytes_used; -- 2.34.1