On mon, 28 Nov 2011 06:11:06 -0600, Jonathan Nieder wrote: > Hi, > > Andy Whitcroft wrote: > >> 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! > [...] >> BugLink: http://bugs.launchpad.net/bugs/816770 >> Signed-off-by: Andy Whitcroft <a...@canonical.com> >> --- > > Fixes http://bugs.debian.org/649847 > Tested-by: Ivan Vilata i Balaguer <i...@selidor.net> > > This patch fixes a regression introduced by 6d07bcec969a ("btrfs: fix > wrong free space information of btrfs"), which hit mainline in > v2.6.38-rc1. Josef Bacik acked the patch, but I can't seem to find it > in linux-next, linux-btrfs, or Josef's btrfs-work tree. Maybe it was > just forgotten. > > What can I do to help this patch get unstuck?
I think We should make this behaviour similar to the traditional file systems, such as ext3/4. That is the available space should show the size of all the free space which we may used to store the file data, even we mount it on the read-only mode. This patch didn't fix the problem completely. Thanks Miao >> 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-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
