On Mon, 2023-02-13 at 19:10 +0800, xiubli@xxxxxxxxxx wrote:
> From: Xiubo Li <xiubli@xxxxxxxxxx>
>
> The fallocate will try to clear the suid/sgid if a unprevileged user
> changed the file.
>
> There is no Posix item requires that we should clear the suid/sgid
> in fallocate code path but this is the default behaviour for most of
> the filesystems and the VFS layer. And also the same for the write
> code path, which have already support it.
>
Huh, you're right. It really doesn't say anything about the timestamps
or setuid bits:
https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
That's arguably a bug in the spec. It really does need to do those
things.
> And also we need to update the time stamps since the fallocate will
> change the file contents.
>
> Cc: stable@xxxxxxxxxxxxxxx
> URL: https://tracker.ceph.com/issues/58054
> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> ---
> fs/ceph/file.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 903de296f0d3..dee3b445f415 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -2502,6 +2502,9 @@ static long ceph_fallocate(struct file *file, int mode,
> loff_t endoff = 0;
> loff_t size;
>
> + dout("%s %p %llx.%llx mode %x, offset %llu length %llu\n", __func__,
> + inode, ceph_vinop(inode), mode, offset, length);
> +
> if (mode != (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
> return -EOPNOTSUPP;
>
> @@ -2539,6 +2542,10 @@ static long ceph_fallocate(struct file *file, int mode,
> if (ret < 0)
> goto unlock;
>
> + ret = file_modified(file);
> + if (ret)
> + goto put_caps;
> +
> filemap_invalidate_lock(inode->i_mapping);
> ceph_fscache_invalidate(inode, false);
> ceph_zero_pagecache_range(inode, offset, length);
> @@ -2554,6 +2561,7 @@ static long ceph_fallocate(struct file *file, int mode,
> }
> filemap_invalidate_unlock(inode->i_mapping);
>
> +put_caps:
> ceph_put_cap_refs(ci, got);
> unlock:
> inode_unlock(inode);
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
