On Thu, Jun 8, 2017 at 12:55 PM, Olga Kornievskaia <kolga@xxxxxxxxxx> wrote:
> There is a regression by commit 8d40b0f14846 ("NFS filelayout:call
> GETDEVICEINFO after pnfs_layout_process completes"). It leaves the
> DS mount dangling.
>
> Previously, filelayout_alloc_sec() would call filelayout_check_layout()
> which would call nfs4_find_get_deviceid which ups the count on the
> device_id. It's only called once and it's matched by the
> filelayout_free_lseg() that calls nfs4_fl_put_deviceid().
>
> After that patch, each read/write ends up calling nfs4_find_get_deviceid
> and there is no balance for that. Instead, do nfs4_fl_put_deviceid()
> in the filelayout's .pg_cleanup and remove it from filelayout_free_lseg.
>
> Fixes: 8d40b0f14846 ("NFS filelayout:call GETDEVICEINFO after pnfs_layout_process completes")
> Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
> ---
> fs/nfs/filelayout/filelayout.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
> index acd30ba..3c6d043 100644
> --- a/fs/nfs/filelayout/filelayout.c
> +++ b/fs/nfs/filelayout/filelayout.c
> @@ -763,7 +763,6 @@ static void _filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
> struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
>
> dprintk("--> %s\n", __func__);
> - nfs4_fl_put_deviceid(fl->dsaddr);
> /* This assumes a single RW lseg */
> if (lseg->pls_range.iomode == IOMODE_RW) {
> struct nfs4_filelayout *flo;
> @@ -989,18 +988,29 @@ static void _filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
> nfs_pageio_reset_write_mds(pgio);
> }
>
> +static void filelayout_pg_cleanup(struct nfs_pageio_descriptor *desc)
> +{
> + if (desc->pg_lseg) {
> + struct nfs4_filelayout_segment *fl =
> + FILELAYOUT_LSEG(desc->pg_lseg);
> +
> + nfs4_fl_put_deviceid(fl->dsaddr);
> + }
> + pnfs_generic_pg_cleanup(desc);
> +}
> +
> static const struct nfs_pageio_ops filelayout_pg_read_ops = {
> .pg_init = filelayout_pg_init_read,
> .pg_test = filelayout_pg_test,
> .pg_doio = pnfs_generic_pg_readpages,
> - .pg_cleanup = pnfs_generic_pg_cleanup,
> + .pg_cleanup = filelayout_pg_cleanup,
> };
>
> static const struct nfs_pageio_ops filelayout_pg_write_ops = {
> .pg_init = filelayout_pg_init_write,
> .pg_test = filelayout_pg_test,
> .pg_doio = pnfs_generic_pg_writepages,
> - .pg_cleanup = pnfs_generic_pg_cleanup,
> + .pg_cleanup = filelayout_pg_cleanup,
> };
>
> static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
> --
> 1.8.3.1
Needs to do a bit more. It fixes a dangling mount on non-error case.
But on server reboots it leads to ref count imbalance again.
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