diff options
| author | Baptiste Lepers <baptiste.lepers@gmail.com> | 2021-09-06 11:59:24 +1000 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2021-10-03 23:00:50 -0400 |
| commit | a2915fa06227b056a8f9b0d79b61dca08ad5cfc6 (patch) | |
| tree | 5fae6438dabc0e85a70006449f3bcbc311fc8e37 | |
| parent | 36a10a3c4cb6ea7c8bd895c16b3f59e1f0db2f6a (diff) | |
| download | lwn-a2915fa06227b056a8f9b0d79b61dca08ad5cfc6.tar.gz lwn-a2915fa06227b056a8f9b0d79b61dca08ad5cfc6.zip | |
pnfs/flexfiles: Fix misplaced barrier in nfs4_ff_layout_prepare_ds
_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>
| -rw-r--r-- | fs/nfs/flexfilelayout/flexfilelayoutdev.c | 4 | ||||
| -rw-r--r-- | 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 c9b61b818ec1..bfa7202ca7be 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 cf19914fec81..02bd6e83961d 100644 --- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -895,7 +895,7 @@ 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; @@ -973,7 +973,7 @@ 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; |