From: Baptiste Lepers baptiste.lepers@gmail.com
[ Upstream commit a2915fa06227b056a8f9b0d79b61dca08ad5cfc6 ]
_nfs4_pnfs_v3/v4_ds_connect do some work smp_wmb ds->ds_clp = clp;
And nfs4_ff_layout_prepare_ds currently does smp_rmb if(ds->ds_clp) ...
This patch places the smp_rmb after the if. This ensures that following reads only happen once nfs4_ff_layout_prepare_ds has checked that data has been properly initialized.
Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver") Signed-off-by: Baptiste Lepers baptiste.lepers@gmail.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/flexfilelayout/flexfilelayoutdev.c | 4 ++-- fs/nfs/pnfs_nfs.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c index 3eda40a320a53..1f12297109b41 100644 --- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c +++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c @@ -378,10 +378,10 @@ nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, goto noconnect;
ds = mirror->mirror_ds->ds; + if (READ_ONCE(ds->ds_clp)) + goto out; /* matching smp_wmb() in _nfs4_pnfs_v3/4_ds_connect */ smp_rmb(); - if (ds->ds_clp) - goto out;
/* FIXME: For now we assume the server sent only one version of NFS * to use for the DS. diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c index 249cf9037dbd7..aff44a7b98f86 100644 --- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -641,7 +641,7 @@ static int _nfs4_pnfs_v3_ds_connect(struct nfs_server *mds_srv, }
smp_wmb(); - ds->ds_clp = clp; + WRITE_ONCE(ds->ds_clp, clp); dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr); out: return status; @@ -714,7 +714,7 @@ static int _nfs4_pnfs_v4_ds_connect(struct nfs_server *mds_srv, }
smp_wmb(); - ds->ds_clp = clp; + WRITE_ONCE(ds->ds_clp, clp); dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr); out: return status;