ANDROID: Incremental fs: Fix remount

Bug: 153017385
Test: incfs_test passes
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Change-Id: I13f3a3c91d746d725e0e21b1e2bcfe0a64a13716
Git-commit: d73d0b4d33
Git-repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>

fs/incfs/data_mgmt.c

@@ -27,7 +27,6 @@ struct mount_info *incfs_alloc_mount_info(struct super_block *sb,
 		return ERR_PTR(-ENOMEM);
 
 	mi->mi_sb = sb;
-	mi->mi_options = *options;
 	mi->mi_backing_dir_path = *backing_dir_path;
 	mi->mi_owner = get_current_cred();
 	path_get(&mi->mi_backing_dir_path);
@@ -35,26 +34,38 @@ struct mount_info *incfs_alloc_mount_info(struct super_block *sb,
 	mutex_init(&mi->mi_pending_reads_mutex);
 	init_waitqueue_head(&mi->mi_pending_reads_notif_wq);
 	init_waitqueue_head(&mi->mi_log.ml_notif_wq);
+	spin_lock_init(&mi->mi_log.rl_writer_lock);
 	INIT_LIST_HEAD(&mi->mi_reads_list_head);
 
+	error = incfs_realloc_mount_info(mi, options);
+	if (error)
+		goto err;
+
+	return mi;
+
+err:
+	incfs_free_mount_info(mi);
+	return ERR_PTR(error);
+}
+
+int incfs_realloc_mount_info(struct mount_info *mi,
+			     struct mount_options *options)
+{
+	kfree(mi->mi_log.rl_ring_buf);
+	mi->mi_log.rl_ring_buf = NULL;
+	mi->mi_log.rl_size = 0;
+
+	mi->mi_options = *options;
 	if (options->read_log_pages != 0) {
 		size_t buf_size = PAGE_SIZE * options->read_log_pages;
 
-		spin_lock_init(&mi->mi_log.rl_writer_lock);
-
 		mi->mi_log.rl_size = buf_size / sizeof(*mi->mi_log.rl_ring_buf);
 		mi->mi_log.rl_ring_buf = kzalloc(buf_size, GFP_NOFS);
-		if (!mi->mi_log.rl_ring_buf) {
-			error = -ENOMEM;
-			goto err;
-		}
+		if (!mi->mi_log.rl_ring_buf)
+			return -ENOMEM;
 	}
 
-	return mi;
-
-err:
-	incfs_free_mount_info(mi);
-	return ERR_PTR(error);
+	return 0;
 }
 
 void incfs_free_mount_info(struct mount_info *mi)

fs/incfs/data_mgmt.h

@@ -249,6 +249,9 @@ struct mount_info *incfs_alloc_mount_info(struct super_block *sb,
 					  struct mount_options *options,
 					  struct path *backing_dir_path);
 
+int incfs_realloc_mount_info(struct mount_info *mi,
+			     struct mount_options *options);
+
 void incfs_free_mount_info(struct mount_info *mi);
 
 struct data_file *incfs_open_data_file(struct mount_info *mi, struct file *bf);

fs/incfs/vfs.c

@@ -2218,10 +2218,9 @@ static int incfs_remount_fs(struct super_block *sb, int *flags, char *data)
 	if (err)
 		return err;
 
-	if (mi->mi_options.read_timeout_ms != options.read_timeout_ms) {
-		mi->mi_options.read_timeout_ms = options.read_timeout_ms;
-		pr_debug("incfs: new timeout_ms=%d", options.read_timeout_ms);
-	}
+	err = incfs_realloc_mount_info(mi, &options);
+	if (err)
+		return err;
 
 	pr_debug("incfs: remount\n");
 	return 0;

tools/testing/selftests/filesystems/incfs/incfs_test.c

@@ -2029,14 +2029,14 @@ static int read_log_test(char *mount_dir)
 	struct test_files_set test = get_test_files_set();
 	const int file_num = test.files_count;
 	int i = 0;
-	int cmd_fd = -1, log_fd = -1;
+	int cmd_fd = -1, log_fd = -1, drop_caches = -1;
 	char *backing_dir;
 
 	backing_dir = create_backing_dir(mount_dir);
 	if (!backing_dir)
 		goto failure;
 
-	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0") != 0)
+	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0", false) != 0)
 		goto failure;
 
 	cmd_fd = open_commands_file(mount_dir);
@@ -2076,7 +2076,7 @@ static int read_log_test(char *mount_dir)
 		goto failure;
 	}
 
-	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0") != 0)
+	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0", false) != 0)
 		goto failure;
 
 	cmd_fd = open_commands_file(mount_dir);
@@ -2106,8 +2106,8 @@ static int read_log_test(char *mount_dir)
 		goto failure;
 	}
 
-	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0,rlog_pages=0") !=
-	    0)
+	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0,rlog_pages=0",
+			 false) != 0)
 		goto failure;
 
 	log_fd = open_log_file(mount_dir);
@@ -2122,6 +2122,29 @@ static int read_log_test(char *mount_dir)
 			goto failure;
 	}
 
+	/*
+	 * Remount and check that logs start working again
+	 */
+	drop_caches = open("/proc/sys/vm/drop_caches", O_WRONLY);
+	if (drop_caches == -1)
+		goto failure;
+	i = write(drop_caches, "3", 1);
+	close(drop_caches);
+	if (i != 1)
+		goto failure;
+
+	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0,rlog_pages=4",
+			 true) != 0)
+		goto failure;
+
+	/* Validate data again */
+	for (i = 0; i < file_num; i++) {
+		struct test_file *file = &test.files[i];
+
+		if (validate_logs(mount_dir, log_fd, file, false))
+			goto failure;
+	}
+
 	/* Final unmount */
 	close(log_fd);
 	free(backing_dir);
@@ -2320,7 +2343,7 @@ static int get_blocks_test(char *mount_dir)
 	if (!backing_dir)
 		goto failure;
 
-	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0") != 0)
+	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0", false) != 0)
 		goto failure;
 
 	cmd_fd = open_commands_file(mount_dir);
@@ -2495,7 +2518,7 @@ static int get_hash_blocks_test(char *mount_dir)
 	if (!backing_dir)
 		goto failure;
 
-	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0") != 0)
+	if (mount_fs_opt(mount_dir, backing_dir, "readahead=0", false) != 0)
 		goto failure;
 
 	cmd_fd = open_commands_file(mount_dir);

tools/testing/selftests/filesystems/incfs/utils.c

@@ -41,12 +41,13 @@ int mount_fs(const char *mount_dir, const char *backing_dir,
 }
 
 int mount_fs_opt(const char *mount_dir, const char *backing_dir,
-		 const char *opt)
+		 const char *opt, bool remount)
 {
 	static const char fs_name[] = INCFS_NAME;
 	int result;
 
-	result = mount(backing_dir, mount_dir, fs_name, 0, opt);
+	result = mount(backing_dir, mount_dir, fs_name,
+		       remount ? MS_REMOUNT : 0, opt);
 	if (result != 0)
 		perror("Error mounting fs.");
 	return result;

tools/testing/selftests/filesystems/incfs/utils.h

@@ -23,7 +23,7 @@ int mount_fs(const char *mount_dir, const char *backing_dir,
 	     int read_timeout_ms);
 
 int mount_fs_opt(const char *mount_dir, const char *backing_dir,
-		 const char *opt);
+		 const char *opt, bool remount);
 
 int get_file_bmap(int cmd_fd, int ino, unsigned char *buf, int buf_size);