On Mon, Apr 23, 2018 at 11:42:42AM +0900, Misono Tomohiro wrote:
> On 2018/04/21 2:02, David Sterba wrote:
> > The new ioctl is an extension to the FS_IOC_SETFLAGS and adds new
> > flags and is extensible. Don't get fooled by the XATTR in the name, it
> > does not have anything in common with the extended attributes,
> > incidentally also abbreviated as XATTRs.
> >
> > This patch allows to set the xflags portion of the fsxattr structure,
> > other items have no meaning and non-zero values will result in
> > EOPNOTSUPP.
> >
> > Currently supported xflags:
> >
> > - APPEND
> > - IMMUTABLE
> > - NOATIME
> > - NODUMP
> > - SYNC
> >
> > The structure of btrfs_ioctl_fssetxattr copies btrfs_ioctl_setflags but
> > is simpler on the flag setting side.
> >
> > The original patch was written by Chandan Jay Sharma but was incomplete
> > and no further revision has been sent.
> >
> > Based-on-patches-by: Chandan Jay Sharma <chandansbg@xxxxxxxxx>
> > Signed-off-by: David Sterba <dsterba@xxxxxxxx>
> > ---
> > fs/btrfs/ioctl.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 94 insertions(+)
> >
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index 52b12ab9b82b..4fd61f191bba 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -388,6 +388,98 @@ static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
> > return 0;
> > }
> >
> > +static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
> > +{
> > + struct inode *inode = file_inode(file);
> > + struct btrfs_inode *binode = BTRFS_I(inode);
> > + struct btrfs_root *root = binode->root;
> > + struct btrfs_trans_handle *trans;
> > + struct fsxattr fa;
> > + unsigned oldflags;
> > + unsigned old_i_flags;
> > + int ret = 0;
> > +
> > + if (!inode_owner_or_capable(inode))
> > + return -EPERM;
> > +
> > + if (btrfs_root_readonly(root))
> > + return -EROFS;
> > +
> > + memset(&fa, 0, sizeof(fa));
> > + if (copy_from_user(&fa, arg, sizeof(fa)))
> > + return -EFAULT;
> > +
> > + ret = check_xflags(fa.fsx_xflags);
> > + if (ret)
> > + return ret;
> > +
> > + if (fa.fsx_extsize != 0 || fa.fsx_projid != 0 || fa.fsx_cowextsize != 0)
> > + return -EOPNOTSUPP;
> > +
> > + ret = mnt_want_write_file(file);
> > + if (ret)
> > + return ret;
> > +
> > + inode_lock(inode);
> > +
> > + oldflags = binode->flags;
> > + old_i_flags = inode->i_flags;
> > +
> > + /* We need the capabilities to change append-only or immutable inode */
> > + if (((oldflags & (BTRFS_INODE_APPEND | BTRFS_INODE_IMMUTABLE)) ||
> > + (fa.fsx_xflags & (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE))) &&
> > + !capable(CAP_LINUX_IMMUTABLE)) {
> > + ret = -EPERM;
> > + goto out_unlock;
> > + }
> > +
> > + if (fa.fsx_xflags & FS_XFLAG_SYNC)
> > + binode->flags |= BTRFS_INODE_SYNC;
> > + else
> > + binode->flags &= ~BTRFS_INODE_SYNC;
> > + if (fa.fsx_xflags & FS_XFLAG_IMMUTABLE)
> > + binode->flags |= BTRFS_INODE_IMMUTABLE;
> > + else
> > + binode->flags &= ~BTRFS_INODE_IMMUTABLE;
> > + if (fa.fsx_xflags & FS_XFLAG_APPEND)
> > + binode->flags |= BTRFS_INODE_APPEND;
> > + else
> > + binode->flags &= ~BTRFS_INODE_APPEND;
> > + if (fa.fsx_xflags & FS_XFLAG_NODUMP)
> > + binode->flags |= BTRFS_INODE_NODUMP;
> > + else
> > + binode->flags &= ~BTRFS_INODE_NODUMP;
> > + if (fa.fsx_xflags & FS_XFLAG_NOATIME)
> > + binode->flags |= BTRFS_INODE_NOATIME;
> > + else
> > + binode->flags &= ~BTRFS_INODE_NOATIME;
> > +
> > + /* 1 item for the inode */
> > + trans = btrfs_start_transaction(root, 1);
> > + if (IS_ERR(trans)) {
> > + ret = PTR_ERR(trans);
> > + goto out_drop;
> > + }
> > +
> > + btrfs_sync_inode_flags_to_i_flags(inode);
> > + inode_inc_iversion(inode);
> > + inode->i_ctime = current_time(inode);
> > + ret = btrfs_update_inode(trans, root, inode);
> > +
> > + btrfs_end_transaction(trans);
>
> Shouldn't out_drop label be here?
> Otherwise, above "goto out_drop" won't unlock nor restore the flag value.
Right, will fix, thanks.
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