[LTS 9.4] CVE-2025-39697, CVE-2025-38248

fs/nfs/direct.c

@@ -488,7 +488,9 @@ static void nfs_direct_add_page_head(struct list_head *list,
 	kref_get(&head->wb_kref);
 }
 
-static void nfs_direct_join_group(struct list_head *list, struct inode *inode)
+static void nfs_direct_join_group(struct list_head *list,
+				  struct nfs_commit_info *cinfo,
+				  struct inode *inode)
 {
 	struct nfs_page *req, *subreq;
 
@@ -510,7 +512,7 @@ static void nfs_direct_join_group(struct list_head *list, struct inode *inode)
 				nfs_release_request(subreq);
 			}
 		} while ((subreq = subreq->wb_this_page) != req);
-		nfs_join_page_group(req, inode);
+		nfs_join_page_group(req, cinfo, inode);
 	}
 }
 
@@ -536,7 +538,7 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
 	nfs_init_cinfo_from_dreq(&cinfo, dreq);
 	nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
 
-	nfs_direct_join_group(&reqs, dreq->inode);
+	nfs_direct_join_group(&reqs, &cinfo, dreq->inode);
 
 	dreq->count = 0;
 	dreq->max_count = 0;

fs/nfs/pagelist.c

@@ -205,83 +205,6 @@ nfs_page_group_lock_head(struct nfs_page *req)
 	return head;
 }
 
-/*
- * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req
- * @head: head request of page group, must be holding head lock
- * @req: request that couldn't lock and needs to wait on the req bit lock
- *
- * This is a helper function for nfs_lock_and_join_requests
- * returns 0 on success, < 0 on error.
- */
-static void
-nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
-{
-	struct nfs_page *tmp;
-
-	/* relinquish all the locks successfully grabbed this run */
-	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
-		if (!kref_read(&tmp->wb_kref))
-			continue;
-		nfs_unlock_and_release_request(tmp);
-	}
-}
-
-/*
- * nfs_page_group_lock_subreq -  try to lock a subrequest
- * @head: head request of page group
- * @subreq: request to lock
- *
- * This is a helper function for nfs_lock_and_join_requests which
- * must be called with the head request and page group both locked.
- * On error, it returns with the page group unlocked.
- */
-static int
-nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
-{
-	int ret;
-
-	if (!kref_get_unless_zero(&subreq->wb_kref))
-		return 0;
-	while (!nfs_lock_request(subreq)) {
-		nfs_page_group_unlock(head);
-		ret = nfs_wait_on_request(subreq);
-		if (!ret)
-			ret = nfs_page_group_lock(head);
-		if (ret < 0) {
-			nfs_unroll_locks(head, subreq);
-			nfs_release_request(subreq);
-			return ret;
-		}
-	}
-	return 0;
-}
-
-/*
- * nfs_page_group_lock_subrequests -  try to lock the subrequests
- * @head: head request of page group
- *
- * This is a helper function for nfs_lock_and_join_requests which
- * must be called with the head request locked.
- */
-int nfs_page_group_lock_subrequests(struct nfs_page *head)
-{
-	struct nfs_page *subreq;
-	int ret;
-
-	ret = nfs_page_group_lock(head);
-	if (ret < 0)
-		return ret;
-	/* lock each request in the page group */
-	for (subreq = head->wb_this_page; subreq != head;
-			subreq = subreq->wb_this_page) {
-		ret = nfs_page_group_lock_subreq(head, subreq);
-		if (ret < 0)
-			return ret;
-	}
-	nfs_page_group_unlock(head);
-	return 0;
-}
-
 /*
  * nfs_page_set_headlock - set the request PG_HEADLOCK
  * @req: request that is to be locked
@@ -348,13 +271,14 @@ nfs_page_group_unlock(struct nfs_page *req)
 	nfs_page_clear_headlock(req);
 }
 
-/*
- * nfs_page_group_sync_on_bit_locked
+/**
+ * nfs_page_group_sync_on_bit_locked - Test if all requests have @bit set
+ * @req: request in page group
+ * @bit: PG_* bit that is used to sync page group
  *
  * must be called with page group lock held
  */
-static bool
-nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
+bool nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
 {
 	struct nfs_page *head = req->wb_head;
 	struct nfs_page *tmp;

fs/nfs/write.c

@@ -58,7 +58,8 @@ static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
 static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
 static const struct nfs_rw_ops nfs_rw_write_ops;
 static void nfs_inode_remove_request(struct nfs_page *req);
-static void nfs_clear_request_commit(struct nfs_page *req);
+static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
+				     struct nfs_page *req);
 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 				      struct inode *inode);
 static struct nfs_page *
@@ -154,20 +155,10 @@ nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode)
 	}
 }
 
-static int
-nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
+static void nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
 {
-	int ret;
-
-	if (!test_bit(PG_REMOVE, &req->wb_flags))
-		return 0;
-	ret = nfs_page_group_lock(req);
-	if (ret)
-		return ret;
 	if (test_and_clear_bit(PG_REMOVE, &req->wb_flags))
 		nfs_page_set_inode_ref(req, inode);
-	nfs_page_group_unlock(req);
-	return 0;
 }
 
 static struct nfs_page *nfs_folio_private_request(struct folio *folio)
@@ -236,36 +227,6 @@ static struct nfs_page *nfs_folio_find_head_request(struct folio *folio)
 	return req;
 }
 
-static struct nfs_page *nfs_folio_find_and_lock_request(struct folio *folio)
-{
-	struct inode *inode = folio_file_mapping(folio)->host;
-	struct nfs_page *req, *head;
-	int ret;
-
-	for (;;) {
-		req = nfs_folio_find_head_request(folio);
-		if (!req)
-			return req;
-		head = nfs_page_group_lock_head(req);
-		if (head != req)
-			nfs_release_request(req);
-		if (IS_ERR(head))
-			return head;
-		ret = nfs_cancel_remove_inode(head, inode);
-		if (ret < 0) {
-			nfs_unlock_and_release_request(head);
-			return ERR_PTR(ret);
-		}
-		/* Ensure that nobody removed the request before we locked it */
-		if (head == nfs_folio_private_request(folio))
-			break;
-		if (folio_test_swapcache(folio))
-			break;
-		nfs_unlock_and_release_request(head);
-	}
-	return head;
-}
-
 /* Adjust the file length if we're writing beyond the end */
 static void nfs_grow_file(struct folio *folio, unsigned int offset,
 			  unsigned int count)
@@ -501,8 +462,8 @@ nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
  * the (former) group.  All subrequests are removed from any write or commit
  * lists, unlinked from the group and destroyed.
  */
-void
-nfs_join_page_group(struct nfs_page *head, struct inode *inode)
+void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
+			 struct inode *inode)
 {
 	struct nfs_page *subreq;
 	struct nfs_page *destroy_list = NULL;
@@ -532,7 +493,7 @@ nfs_join_page_group(struct nfs_page *head, struct inode *inode)
 	 * Commit list removal accounting is done after locks are dropped */
 	subreq = head;
 	do {
-		nfs_clear_request_commit(subreq);
+		nfs_clear_request_commit(cinfo, subreq);
 		subreq = subreq->wb_this_page;
 	} while (subreq != head);
 
@@ -546,6 +507,57 @@ nfs_join_page_group(struct nfs_page *head, struct inode *inode)
 	nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 }
 
+/*
+ * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req
+ * @head: head request of page group, must be holding head lock
+ * @req: request that couldn't lock and needs to wait on the req bit lock
+ *
+ * This is a helper function for nfs_lock_and_join_requests
+ * returns 0 on success, < 0 on error.
+ */
+static void
+nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
+{
+	struct nfs_page *tmp;
+
+	/* relinquish all the locks successfully grabbed this run */
+	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
+		if (!kref_read(&tmp->wb_kref))
+			continue;
+		nfs_unlock_and_release_request(tmp);
+	}
+}
+
+/*
+ * nfs_page_group_lock_subreq -  try to lock a subrequest
+ * @head: head request of page group
+ * @subreq: request to lock
+ *
+ * This is a helper function for nfs_lock_and_join_requests which
+ * must be called with the head request and page group both locked.
+ * On error, it returns with the page group unlocked.
+ */
+static int
+nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
+{
+	int ret;
+
+	if (!kref_get_unless_zero(&subreq->wb_kref))
+		return 0;
+	while (!nfs_lock_request(subreq)) {
+		nfs_page_group_unlock(head);
+		ret = nfs_wait_on_request(subreq);
+		if (!ret)
+			ret = nfs_page_group_lock(head);
+		if (ret < 0) {
+			nfs_unroll_locks(head, subreq);
+			nfs_release_request(subreq);
+			return ret;
+		}
+	}
+	return 0;
+}
+
 /*
  * nfs_lock_and_join_requests - join all subreqs to the head req
  * @folio: the folio used to lookup the "page group" of nfs_page structures
@@ -564,28 +576,59 @@ nfs_join_page_group(struct nfs_page *head, struct inode *inode)
 static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)
 {
 	struct inode *inode = folio_file_mapping(folio)->host;
-	struct nfs_page *head;
+	struct nfs_page *head, *subreq;
+	struct nfs_commit_info cinfo;
 	int ret;
 
 	/*
 	 * A reference is taken only on the head request which acts as a
 	 * reference to the whole page group - the group will not be destroyed
 	 * until the head reference is released.
 	 */
-	head = nfs_folio_find_and_lock_request(folio);
-	if (IS_ERR_OR_NULL(head))
-		return head;
+retry:
+	head = nfs_folio_find_head_request(folio);
+	if (!head)
+		return NULL;
 
-	/* lock each request in the page group */
-	ret = nfs_page_group_lock_subrequests(head);
-	if (ret < 0) {
+	while (!nfs_lock_request(head)) {
+		ret = nfs_wait_on_request(head);
+		if (ret < 0) {
+			nfs_release_request(head);
+			return ERR_PTR(ret);
+		}
+	}
+
+	ret = nfs_page_group_lock(head);
+	if (ret < 0)
+		goto out_unlock;
+
+	/* Ensure that nobody removed the request before we locked it */
+	if (head != folio->private && !folio_test_swapcache(folio)) {
+		nfs_page_group_unlock(head);
 		nfs_unlock_and_release_request(head);
-		return ERR_PTR(ret);
+		goto retry;
+	}
+
+	nfs_cancel_remove_inode(head, inode);
+
+	/* lock each request in the page group */
+	for (subreq = head->wb_this_page;
+	     subreq != head;
+	     subreq = subreq->wb_this_page) {
+		ret = nfs_page_group_lock_subreq(head, subreq);
+		if (ret < 0)
+			goto out_unlock;
 	}
 
-	nfs_join_page_group(head, inode);
+	nfs_page_group_unlock(head);
 
+	nfs_init_cinfo_from_inode(&cinfo, inode);
+	nfs_join_page_group(head, &cinfo, inode);
 	return head;
+
+out_unlock:
+	nfs_unlock_and_release_request(head);
+	return ERR_PTR(ret);
 }
 
 static void nfs_write_error(struct nfs_page *req, int error)
@@ -772,7 +815,8 @@ static void nfs_inode_remove_request(struct nfs_page *req)
 {
 	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
 
-	if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
+	nfs_page_group_lock(req);
+	if (nfs_page_group_sync_on_bit_locked(req, PG_REMOVE)) {
 		struct folio *folio = nfs_page_to_folio(req->wb_head);
 		struct address_space *mapping = folio_file_mapping(folio);
 
@@ -784,6 +828,7 @@ static void nfs_inode_remove_request(struct nfs_page *req)
 		}
 		spin_unlock(&mapping->private_lock);
 	}
+	nfs_page_group_unlock(req);
 
 	if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
 		atomic_long_dec(&nfsi->nrequests);
@@ -942,18 +987,16 @@ static void nfs_folio_clear_commit(struct folio *folio)
 }
 
 /* Called holding the request lock on @req */
-static void
-nfs_clear_request_commit(struct nfs_page *req)
+static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
+				     struct nfs_page *req)
 {
 	if (test_bit(PG_CLEAN, &req->wb_flags)) {
 		struct nfs_open_context *ctx = nfs_req_openctx(req);
 		struct inode *inode = d_inode(ctx->dentry);
-		struct nfs_commit_info cinfo;
 
-		nfs_init_cinfo_from_inode(&cinfo, inode);
 		mutex_lock(&NFS_I(inode)->commit_mutex);
-		if (!pnfs_clear_request_commit(req, &cinfo)) {
-			nfs_request_remove_commit_list(req, &cinfo);
+		if (!pnfs_clear_request_commit(req, cinfo)) {
+			nfs_request_remove_commit_list(req, cinfo);
 		}
 		mutex_unlock(&NFS_I(inode)->commit_mutex);
 		nfs_folio_clear_commit(nfs_page_to_folio(req));