NFS: Fix a COMMIT race in pNFS

We must make sure that cinfo->ds->nwritten is in sync with the
commit list, since it is checked as part of pnfs_scan_commit_lists().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index d40755a0984b..3e6de85faf42 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -159,13 +159,18 @@ void pnfs_generic_recover_commit_reqs(struct list_head *dst,
 {
         struct pnfs_commit_bucket *b;
         struct pnfs_layout_segment *freeme;
+        int nwritten;
         int i;
 
         lockdep_assert_held(&cinfo->inode->i_lock);
 restart:
         for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
-                if (pnfs_generic_transfer_commit_list(&b->written, dst,
-                                                      cinfo, 0)) {
+                nwritten = pnfs_generic_transfer_commit_list(&b->written,
+                                dst, cinfo, 0);
+                if (!nwritten)
+                        continue;
+                cinfo->ds->nwritten -= nwritten;
+                if (list_empty(&b->written)) {
                         freeme = b->wlseg;
                         b->wlseg = NULL;
                         spin_unlock(&cinfo->inode->i_lock);
@@ -174,7 +179,6 @@ restart:
                         goto restart;
                 }
         }
-        cinfo->ds->nwritten = 0;
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);