Hi Jeff and Omar,
On Sun, 2025-05-11 at 09:28 -0400, trondmy@xxxxxxxxxx wrote:
> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>
> If there are still layout segments in the layout plh_return_lsegs
> list
> after a layout return, we should be resetting the state to ensure
> they
> eventually get returned as well.
>
> Fixes: 68f744797edd ("pNFS: Do not free layout segments that are
> marked for return")
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/pnfs.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 10fdd065a61c..fc7c5fb10198 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -745,6 +745,14 @@ pnfs_mark_matching_lsegs_invalid(struct
> pnfs_layout_hdr *lo,
> return remaining;
> }
>
> +static void pnfs_reset_return_info(struct pnfs_layout_hdr *lo)
> +{
> + struct pnfs_layout_segment *lseg;
> +
> + list_for_each_entry(lseg, &lo->plh_return_segs, pls_list)
> + pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
> +}
> +
> static void
> pnfs_free_returned_lsegs(struct pnfs_layout_hdr *lo,
> struct list_head *free_me,
> @@ -1292,6 +1300,7 @@ void pnfs_layoutreturn_free_lsegs(struct
> pnfs_layout_hdr *lo,
> pnfs_mark_matching_lsegs_invalid(lo, &freeme, range, seq);
> pnfs_free_returned_lsegs(lo, &freeme, range, seq);
> pnfs_set_layout_stateid(lo, stateid, NULL, true);
> + pnfs_reset_return_info(lo);
> } else
> pnfs_mark_layout_stateid_invalid(lo, &freeme);
> out_unlock:
Could the above bug perhaps explain the issue with leaked layout
segments that you were seeing?
If the client doesn't set NFS_LAYOUT_RETURN_REQUESTED, and the server
is unable to recall the layout due to the network getting shut down,
then it seems to me that these layout segments just disappear down a
black hole.
IOW: the scenario is something like this:
* The client holds a read and a read/write layout.
* The server recalls the read layout.
* The client closes the file while the recall is being processed, so
that the read and read/write layout segments are both put on the
plh_return_segs list.
* The client returns the read layout, and clears the associated read
layout segments. The read/write layout segments are still on the
list, but without NFS_LAYOUT_RETURN_REQUESTED being set.
Cheers
Trond
--
Trond Myklebust Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
