NFSv4: Fix an Oops in pnfs_mark_request_commit() when doing O_DIRECT

Fix an Oopsable condition in pnfs_mark_request_commit() when we're
putting a set of writes on the commit list to reschedule them after a
failed pNFS attempt.

Fixes: 9c455a8c1e14 ("NFS/pNFS: Clean up pNFS commit operations")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 2d30a4d..2e894fe 100644 (file)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -700,8 +700,8 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
 {
        struct nfs_direct_req *dreq = hdr->dreq;
        struct nfs_commit_info cinfo;
-       bool request_commit = false;
        struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+       int flags = NFS_ODIRECT_DONE;
 
        nfs_init_cinfo_from_dreq(&cinfo, dreq);
 
@@ -713,15 +713,9 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
 
        nfs_direct_count_bytes(dreq, hdr);
        if (hdr->good_bytes != 0 && nfs_write_need_commit(hdr)) {
-               switch (dreq->flags) {
-               case 0:
+               if (!dreq->flags)
                        dreq->flags = NFS_ODIRECT_DO_COMMIT;
-                       request_commit = true;
-                       break;
-               case NFS_ODIRECT_RESCHED_WRITES:
-               case NFS_ODIRECT_DO_COMMIT:
-                       request_commit = true;
-               }
+               flags = dreq->flags;
        }
        spin_unlock(&dreq->lock);
 
@@ -729,12 +723,15 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
 
                req = nfs_list_entry(hdr->pages.next);
                nfs_list_remove_request(req);
-               if (request_commit) {
+               if (flags == NFS_ODIRECT_DO_COMMIT) {
                        kref_get(&req->wb_kref);
                        memcpy(&req->wb_verf, &hdr->verf.verifier,
                               sizeof(req->wb_verf));
                        nfs_mark_request_commit(req, hdr->lseg, &cinfo,
                                hdr->ds_commit_idx);
+               } else if (flags == NFS_ODIRECT_RESCHED_WRITES) {
+                       kref_get(&req->wb_kref);
+                       nfs_mark_request_commit(req, NULL, &cinfo, 0);
                }
                nfs_unlock_and_release_request(req);
        }