Merge tag 'nfs-for-4.7-2' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client bugfixes from Anna Schumaker:
 "Stable bugfixes:
   - Fix _cancel_empty_pagelist
   - Fix a double page unlock
   - Make nfs_atomic_open() call d_drop() on all ->open_context() errors.
   - Fix another OPEN_DOWNGRADE bug

  Other bugfixes:
   - Ensure we handle delegation errors in nfs4_proc_layoutget()
   - Layout stateids start out as being invalid
   - Add sparse lock annotations for pnfs_find_alloc_layout
   - Handle bad delegation stateids in nfs4_layoutget_handle_exception
   - Fix up O_DIRECT results
   - Fix potential use after free of state in nfs4_do_reclaim.
   - Mark the layout stateid invalid when all segments are removed
   - Don't let readdirplus revalidate an inode that was marked as stale
   - Fix potential race in nfs_fhget()
   - Fix an unused variable warning"

* tag 'nfs-for-4.7-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFS: Fix another OPEN_DOWNGRADE bug
  make nfs_atomic_open() call d_drop() on all ->open_context() errors.
  NFS: Fix an unused variable warning
  NFS: Fix potential race in nfs_fhget()
  NFS: Don't let readdirplus revalidate an inode that was marked as stale
  NFSv4.1/pnfs: Mark the layout stateid invalid when all segments are removed
  NFS: Fix a double page unlock
  pnfs_nfs: fix _cancel_empty_pagelist
  nfs4: Fix potential use after free of state in nfs4_do_reclaim.
  NFS: Fix up O_DIRECT results
  NFS/pnfs: handle bad delegation stateids in nfs4_layoutget_handle_exception
  NFSv4.1/pnfs: Add sparse lock annotations for pnfs_find_alloc_layout
  NFSv4.1/pnfs: Layout stateids start out as being invalid
  NFSv4.1/pnfs: Ensure we handle delegation errors in nfs4_proc_layoutget()

1 files changed, 10 insertions, 2 deletions

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 0dfc476da3e1..b38e3c0dc790 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -247,7 +247,11 @@ void pnfs_fetch_commit_bucket_list(struct list_head *pages,
 }
 
 /* Helper function for pnfs_generic_commit_pagelist to catch an empty
- * page list. This can happen when two commits race. */
+ * page list. This can happen when two commits race.
+ *
+ * This must be called instead of nfs_init_commit - call one or the other, but
+ * not both!
+ */
 static bool
 pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
 					  struct nfs_commit_data *data,
@@ -256,7 +260,11 @@ pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
 	if (list_empty(pages)) {
 		if (atomic_dec_and_test(&cinfo->mds->rpcs_out))
 			wake_up_atomic_t(&cinfo->mds->rpcs_out);
-		nfs_commitdata_release(data);
+		/* don't call nfs_commitdata_release - it tries to put
+		 * the open_context which is not acquired until nfs_init_commit
+		 * which has not been called on @data */
+		WARN_ON_ONCE(data->context);
+		nfs_commit_free(data);
 		return true;
 	}