commit b83cc9693f39689490970c19f6c5b866f6719a70
author Li Zefan <lizf@cn.fujitsu.com> Mon Dec 20 16:04:08 2010 +0800
committer Li Zefan <lizf@cn.fujitsu.com> Thu Dec 23 08:49:17 2010 +0800
tree b86d09884015fce195a4ac5ff1e8ec5f6ec00677
parent fa0d2b9bd717340e0bc4850a80ac0eb344e9a7fb

Btrfs: Add readonly snapshots support

Usage:

Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and call
ioctl(BTRFS_I0CTL_SNAP_CREATE_V2).

Implementation:

- Set readonly bit of btrfs_root_item->flags.
- Add readonly checks in btrfs_permission (inode_permission),
btrfs_setattr, btrfs_set/remove_xattr and some ioctls.

Changelog for v3:

- Eliminate btrfs_root->readonly, but check btrfs_root->root_item.flags.
- Rename BTRFS_ROOT_SNAP_RDONLY to BTRFS_ROOT_SUBVOL_RDONLY.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>