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authorLi Zefan <lizf@cn.fujitsu.com>2010-12-20 16:04:08 +0800
committerLi Zefan <lizf@cn.fujitsu.com>2010-12-23 08:49:17 +0800
commitb83cc9693f39689490970c19f6c5b866f6719a70 (patch)
treeb86d09884015fce195a4ac5ff1e8ec5f6ec00677 /fs/btrfs/transaction.c
parentfa0d2b9bd717340e0bc4850a80ac0eb344e9a7fb (diff)
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>
Diffstat (limited to 'fs/btrfs/transaction.c')
-rw-r--r--fs/btrfs/transaction.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index f50e931fc217..29e30d832ec9 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -910,6 +910,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
u64 to_reserve = 0;
u64 index = 0;
u64 objectid;
+ u64 root_flags;
new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
if (!new_root_item) {
@@ -967,6 +968,13 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
+ root_flags = btrfs_root_flags(new_root_item);
+ if (pending->readonly)
+ root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
+ else
+ root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
+ btrfs_set_root_flags(new_root_item, root_flags);
+
old = btrfs_lock_root_node(root);
btrfs_cow_block(trans, root, old, NULL, 0, &old);
btrfs_set_lock_blocking(old);