On Tue, 2021-11-16 at 17:20 +0800, xiubli@xxxxxxxxxx wrote:
> From: Xiubo Li <xiubli@xxxxxxxxxx>
>
> In case truncating a file to a smaller sizeA, the sizeA will be kept
> in truncate_size. And if truncate the file to a bigger sizeB, the
> MDS will only increase the truncate_seq, but still using the sizeA as
> the truncate_size.
>
Do you mean "kept in ci->i_truncate_size" ? If so, is this really the
correct fix? I'll note this in the sources:
u32 i_truncate_seq; /* last truncate to smaller size */
u64 i_truncate_size; /* and the size we last truncated down to */
Maybe the MDS ought not bump the truncate_seq unless it was truncating
to a smaller size? If not, then that comment seems wrong at least.
> So when filling the inode it will truncate the pagecache by using
> truncate_sizeA again, which makes no sense and will trim the inocent
> pages.
>
Is there a reproducer for this? It would be nice to put something in
xfstests for it if so.
> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> ---
> fs/ceph/inode.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 1b4ce453d397..b4f784684e64 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -738,10 +738,11 @@ int ceph_fill_file_size(struct inode *inode, int issued,
> * don't hold those caps, then we need to check whether
> * the file is either opened or mmaped
> */
> - if ((issued & (CEPH_CAP_FILE_CACHE|
> + if (ci->i_truncate_size != truncate_size &&
> + ((issued & (CEPH_CAP_FILE_CACHE|
> CEPH_CAP_FILE_BUFFER)) ||
> mapping_mapped(inode->i_mapping) ||
> - __ceph_is_file_opened(ci)) {
> + __ceph_is_file_opened(ci))) {
> ci->i_truncate_pending++;
> queue_trunc = 1;
> }
--
Jeff Layton <jlayton@xxxxxxxxxx>
