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author | Li Zefan <lizf@cn.fujitsu.com> | 2010-12-20 08:30:25 (GMT) |
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committer | Li Zefan <lizf@cn.fujitsu.com> | 2010-12-23 00:49:19 (GMT) |
commit | 0caa102da82799efaba88e234484786a9591c797 (patch) | |
tree | 748bb0d8054bb85256904ffe29913277e5b80684 /fs/btrfs/ioctl.c | |
parent | b83cc9693f39689490970c19f6c5b866f6719a70 (diff) | |
download | linux-fsl-qoriq-0caa102da82799efaba88e234484786a9591c797.tar.xz |
Btrfs: Add BTRFS_IOC_SUBVOL_GETFLAGS/SETFLAGS ioctls
This allows us to set a snapshot or a subvolume readonly or writable
on the fly.
Usage:
Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and then
call ioctl(BTRFS_IOCTL_SUBVOL_SETFLAGS);
Changelog for v3:
- Change to pass __u64 as ioctl parameter.
Changelog for v2:
- Add _GETFLAGS ioctl.
- Check if the passed fd is the root of a subvolume.
- Change the name from _SNAP_SETFLAGS to _SUBVOL_SETFLAGS.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
-rw-r--r-- | fs/btrfs/ioctl.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index f066ccb..ad19835 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1009,6 +1009,85 @@ out: return ret; } +static noinline int btrfs_ioctl_subvol_getflags(struct file *file, + void __user *arg) +{ + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret = 0; + u64 flags = 0; + + if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) + return -EINVAL; + + down_read(&root->fs_info->subvol_sem); + if (btrfs_root_readonly(root)) + flags |= BTRFS_SUBVOL_RDONLY; + up_read(&root->fs_info->subvol_sem); + + if (copy_to_user(arg, &flags, sizeof(flags))) + ret = -EFAULT; + + return ret; +} + +static noinline int btrfs_ioctl_subvol_setflags(struct file *file, + void __user *arg) +{ + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + u64 root_flags; + u64 flags; + int ret = 0; + + if (root->fs_info->sb->s_flags & MS_RDONLY) + return -EROFS; + + if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) + return -EINVAL; + + if (copy_from_user(&flags, arg, sizeof(flags))) + return -EFAULT; + + if (flags & ~BTRFS_SUBVOL_CREATE_ASYNC) + return -EINVAL; + + if (flags & ~BTRFS_SUBVOL_RDONLY) + return -EOPNOTSUPP; + + down_write(&root->fs_info->subvol_sem); + + /* nothing to do */ + if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root)) + goto out; + + root_flags = btrfs_root_flags(&root->root_item); + if (flags & BTRFS_SUBVOL_RDONLY) + btrfs_set_root_flags(&root->root_item, + root_flags | BTRFS_ROOT_SUBVOL_RDONLY); + else + btrfs_set_root_flags(&root->root_item, + root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY); + + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out_reset; + } + + ret = btrfs_update_root(trans, root, + &root->root_key, &root->root_item); + + btrfs_commit_transaction(trans, root); +out_reset: + if (ret) + btrfs_set_root_flags(&root->root_item, root_flags); +out: + up_write(&root->fs_info->subvol_sem); + return ret; +} + /* * helper to check if the subvolume references other subvolumes */ @@ -2282,6 +2361,10 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_snap_create(file, argp, 1); case BTRFS_IOC_SNAP_DESTROY: return btrfs_ioctl_snap_destroy(file, argp); + case BTRFS_IOC_SUBVOL_GETFLAGS: + return btrfs_ioctl_subvol_getflags(file, argp); + case BTRFS_IOC_SUBVOL_SETFLAGS: + return btrfs_ioctl_subvol_setflags(file, argp); case BTRFS_IOC_DEFAULT_SUBVOL: return btrfs_ioctl_default_subvol(file, argp); case BTRFS_IOC_DEFRAG: |