Merge v6.18.34linux-rolling-lts

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 89 insertions, 31 deletions

diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index d29cc1d01bd2..7293b7effbc1 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -118,7 +118,7 @@ int ksmbd_query_inode_status(struct dentry *dentry)
 		return ret;
 
 	down_read(&ci->m_lock);
-	if (ci->m_flags & (S_DEL_PENDING | S_DEL_ON_CLS))
+	if (ci->m_flags & S_DEL_PENDING)
 		ret = KSMBD_INODE_STATUS_PENDING_DELETE;
 	else
 		ret = KSMBD_INODE_STATUS_OK;
@@ -134,7 +134,7 @@ bool ksmbd_inode_pending_delete(struct ksmbd_file *fp)
 	int ret;
 
 	down_read(&ci->m_lock);
-	ret = (ci->m_flags & (S_DEL_PENDING | S_DEL_ON_CLS));
+	ret = (ci->m_flags & S_DEL_PENDING);
 	up_read(&ci->m_lock);
 
 	return ret;
@@ -302,12 +302,20 @@ static void __ksmbd_inode_close(struct ksmbd_file *fp)
 		}
 	}
 
+	down_write(&ci->m_lock);
+	/* Promote S_DEL_ON_CLS to S_DEL_PENDING when close */
+	if (ci->m_flags & S_DEL_ON_CLS) {
+		ci->m_flags &= ~S_DEL_ON_CLS;
+		ci->m_flags |= S_DEL_PENDING;
+	}
+	up_write(&ci->m_lock);
+
 	if (atomic_dec_and_test(&ci->m_count)) {
 		bool do_unlink = false;
 
 		down_write(&ci->m_lock);
-		if (ci->m_flags & (S_DEL_ON_CLS | S_DEL_PENDING)) {
-			ci->m_flags &= ~(S_DEL_ON_CLS | S_DEL_PENDING);
+		if (ci->m_flags & S_DEL_PENDING) {
+			ci->m_flags &= ~S_DEL_PENDING;
 			do_unlink = true;
 		}
 		up_write(&ci->m_lock);
@@ -325,6 +333,14 @@ static void __ksmbd_remove_durable_fd(struct ksmbd_file *fp)
 		return;
 
 	idr_remove(global_ft.idr, fp->persistent_id);
+	/*
+	 * Clear persistent_id so a later __ksmbd_close_fd() that runs from a
+	 * delayed putter (e.g. when a concurrent ksmbd_lookup_fd_inode()
+	 * walker held the final reference) does not re-issue idr_remove() on
+	 * an id that idr_alloc_cyclic() may have already handed out to a new
+	 * durable handle.
+	 */
+	fp->persistent_id = KSMBD_NO_FID;
 }
 
 static void ksmbd_remove_durable_fd(struct ksmbd_file *fp)
@@ -417,6 +433,20 @@ static struct ksmbd_file *__ksmbd_lookup_fd(struct ksmbd_file_table *ft,
 
 static void __put_fd_final(struct ksmbd_work *work, struct ksmbd_file *fp)
 {
+	/*
+	 * Detached durable fp -- session_fd_check() cleared fp->conn at
+	 * preserve, so this fp is no longer tracked by any conn's
+	 * stats.open_files_count.  This happens when
+	 * ksmbd_scavenger_dispose_dh() hands the final close off to an
+	 * m_fp_list walker (e.g. ksmbd_lookup_fd_inode()) whose work->conn
+	 * is unrelated to the conn that originally opened the handle; close
+	 * via the NULL-ft path so we do not underflow that unrelated
+	 * counter.
+	 */
+	if (!fp->conn) {
+		__ksmbd_close_fd(NULL, fp);
+		return;
+	}
 	__ksmbd_close_fd(&work->sess->file_table, fp);
 	atomic_dec(&work->conn->stats.open_files_count);
 }
@@ -788,24 +818,37 @@ static bool ksmbd_durable_scavenger_alive(void)
 	return true;
 }
 
-static void ksmbd_scavenger_dispose_dh(struct list_head *head)
+static void ksmbd_scavenger_dispose_dh(struct ksmbd_file *fp)
 {
-	while (!list_empty(head)) {
-		struct ksmbd_file *fp;
+	/*
+	 * Durable-preserved fp can remain linked on f_ci->m_fp_list for
+	 * share-mode checks.  Unlink it before final close; fp->node is not
+	 * available as a scavenger-private list node because re-adding it to
+	 * another list corrupts m_fp_list.
+	 */
+	down_write(&fp->f_ci->m_lock);
+	list_del_init(&fp->node);
+	up_write(&fp->f_ci->m_lock);
 
-		fp = list_first_entry(head, struct ksmbd_file, node);
-		list_del_init(&fp->node);
+	/*
+	 * Drop both the durable lifetime reference and the transient reference
+	 * taken by the scavenger under global_ft.lock.  If a concurrent
+	 * ksmbd_lookup_fd_inode() (or any other m_fp_list walker) snatched fp
+	 * before the unlink above, that holder owns the final close via
+	 * ksmbd_fd_put() -> __ksmbd_close_fd().  Otherwise the scavenger is
+	 * the last putter and finalises fp here.
+	 */
+	if (atomic_sub_and_test(2, &fp->refcount))
 		__ksmbd_close_fd(NULL, fp);
-	}
 }
 
 static int ksmbd_durable_scavenger(void *dummy)
 {
 	struct ksmbd_file *fp = NULL;
+	struct ksmbd_file *expired_fp;
 	unsigned int id;
 	unsigned int min_timeout = 1;
 	bool found_fp_timeout;
-	LIST_HEAD(scavenger_list);
 	unsigned long remaining_jiffies;
 
 	__module_get(THIS_MODULE);
@@ -815,8 +858,6 @@ static int ksmbd_durable_scavenger(void *dummy)
 		if (try_to_freeze())
 			continue;
 
-		found_fp_timeout = false;
-
 		remaining_jiffies = wait_event_timeout(dh_wq,
 				   ksmbd_durable_scavenger_alive() == false,
 				   __msecs_to_jiffies(min_timeout));
@@ -825,23 +866,39 @@ static int ksmbd_durable_scavenger(void *dummy)
 		else
 			min_timeout = DURABLE_HANDLE_MAX_TIMEOUT;
 
-		write_lock(&global_ft.lock);
-		idr_for_each_entry(global_ft.idr, fp, id) {
-			if (!fp->durable_timeout)
-				continue;
-
-			if (atomic_read(&fp->refcount) > 1 ||
-			    fp->conn)
-				continue;
-
-			found_fp_timeout = true;
-			if (fp->durable_scavenger_timeout <=
-			    jiffies_to_msecs(jiffies)) {
-				__ksmbd_remove_durable_fd(fp);
-				list_add(&fp->node, &scavenger_list);
-			} else {
+		do {
+			expired_fp = NULL;
+			found_fp_timeout = false;
+
+			write_lock(&global_ft.lock);
+			idr_for_each_entry(global_ft.idr, fp, id) {
 				unsigned long durable_timeout;
 
+				if (!fp->durable_timeout)
+					continue;
+
+				if (atomic_read(&fp->refcount) > 1 ||
+				    fp->conn)
+					continue;
+
+				found_fp_timeout = true;
+				if (fp->durable_scavenger_timeout <=
+				    jiffies_to_msecs(jiffies)) {
+					__ksmbd_remove_durable_fd(fp);
+					/*
+					 * Take a transient reference so fp
+					 * cannot be freed by an in-flight
+					 * ksmbd_lookup_fd_inode() that found
+					 * it through f_ci->m_fp_list while we
+					 * drop global_ft.lock and reach the
+					 * m_fp_list unlink in
+					 * ksmbd_scavenger_dispose_dh().
+					 */
+					atomic_inc(&fp->refcount);
+					expired_fp = fp;
+					break;
+				}
+
 				durable_timeout =
 					fp->durable_scavenger_timeout -
 						jiffies_to_msecs(jiffies);
@@ -849,10 +906,11 @@ static int ksmbd_durable_scavenger(void *dummy)
 				if (min_timeout > durable_timeout)
 					min_timeout = durable_timeout;
 			}
-		}
-		write_unlock(&global_ft.lock);
+			write_unlock(&global_ft.lock);
 
-		ksmbd_scavenger_dispose_dh(&scavenger_list);
+			if (expired_fp)
+				ksmbd_scavenger_dispose_dh(expired_fp);
+		} while (expired_fp);
 
 		if (found_fp_timeout == false)
 			break;