NFS: Fix 2 use after free issues in the I/O code

The writeback code wants to send a commit after processing the pages,
which is why we want to delay releasing the struct path until after
that's done.

Also, the layout code expects that we do not free the inode before
we've put the layout segments in pnfs_writehdr_free() and
pnfs_readhdr_free()

Fixes: 919e3bd9a875 ("NFS: Ensure we commit after writeback is complete")
Fixes: 4714fb51fd03 ("nfs: remove pgio_header refcount, related cleanup")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 12 insertions, 14 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 23cf4a82d94c..bec120ec1967 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -501,16 +501,6 @@ struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
 }
 EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
 
-/*
- * nfs_pgio_header_free - Free a read or write header
- * @hdr: The header to free
- */
-void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
-{
-	hdr->rw_ops->rw_free_header(hdr);
-}
-EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
-
 /**
  * nfs_pgio_data_destroy - make @hdr suitable for reuse
  *
@@ -519,14 +509,24 @@ EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
  *
  * @hdr: A header that has had nfs_generic_pgio called
  */
-void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
+static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
 {
 	if (hdr->args.context)
 		put_nfs_open_context(hdr->args.context);
 	if (hdr->page_array.pagevec != hdr->page_array.page_array)
 		kfree(hdr->page_array.pagevec);
 }
-EXPORT_SYMBOL_GPL(nfs_pgio_data_destroy);
+
+/*
+ * nfs_pgio_header_free - Free a read or write header
+ * @hdr: The header to free
+ */
+void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
+{
+	nfs_pgio_data_destroy(hdr);
+	hdr->rw_ops->rw_free_header(hdr);
+}
+EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
 
 /**
  * nfs_pgio_rpcsetup - Set up arguments for a pageio call
@@ -640,7 +640,6 @@ EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
 static void nfs_pgio_error(struct nfs_pgio_header *hdr)
 {
 	set_bit(NFS_IOHDR_REDO, &hdr->flags);
-	nfs_pgio_data_destroy(hdr);
 	hdr->completion_ops->completion(hdr);
 }
 
@@ -651,7 +650,6 @@ static void nfs_pgio_error(struct nfs_pgio_header *hdr)
 static void nfs_pgio_release(void *calldata)
 {
 	struct nfs_pgio_header *hdr = calldata;
-	nfs_pgio_data_destroy(hdr);
 	hdr->completion_ops->completion(hdr);
 }