Btrfs: set mount options permanently

This patch create space to hold default mount option, and to use saved default mount option change super.c to read default mount option first when mount devices.

Signed-off-by Hidetoshi Seto <[email protected]>

---
 fs/btrfs/ctree.h |    5 ++++-
 fs/btrfs/super.c |    2 ++
 2 files changed, 6 insertions(+), 1 deletions(-)

fs/btrfs/ctree.h +0 -0

index fa5c45b..3eb0551 100644

fs/btrfs/ctree.h +2 -1

+
 	/* future expansion */
-	__le64 reserved[31];
+	__le64 reserved[30];
 	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
 	struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
 } __attribute__ ((__packed__));

fs/btrfs/super.c +0 -0

index e239915..7ef4a2e 100644

Quoted 6 lines · Hidetoshi Seto

fs/btrfs/ctree.h +0 -0

index fa5c45b..3eb0551 100644
@@ -458,8 +458,11 @@ struct btrfs_super_block {
 

fs/btrfs/ctree.h struct btrfs_super_block { · line 462

Quoted 4 lines

fs/btrfs/ctree.h +2 -0

 	__le64 cache_generation;
 
+	/* default mount options */
+	unsigned long default_mount_opt;

you need to use __le64 here, unsigned long has not fixed size

Quoted 8 lines

fs/btrfs/super.c +0 -0

index e239915..7ef4a2e 100644
@@ -340,6 +340,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
 	char *compress_type;
 	bool compress_force = false;
 

fs/btrfs/super.c int btrfs_parse_options(struct btrfs_root *root, char *options) · line 343

Quoted 1 line

fs/btrfs/super.c +1 -0

+	info->mount_opt = info->super_copy->default_mount_opt;

the options have to respect some priority, eg. when I set default options to a filesystem, but mount with a different set, I expect that the explicit flags apply and override the defaults.

I don't remember if this was discussed in the mailinglist or on IRC only, should be easy to dig up if needed.

Quoted 9 lines

fs/btrfs/super.c int btrfs_parse_options(struct btrfs_root *root, char *options) · line 343

Quoted 2 lines

fs/btrfs/super.c +1 -0

+	info->mount_opt = info->super_copy->default_mount_opt;

the options have to respect some priority, eg. when I set default options to a filesystem, but mount with a different set, I expect that the explicit flags apply and override the defaults.

I don't remember if this was discussed in the mailinglist or on IRC only, should be easy to dig up if needed.

At least I don't know whether this was already disscussed or not.

Now my code gives priority to the default options, and it would not be so difficult in case if we have opposing options like "ssd" vs "nossd", and "space_cache" vs "no_space_cache"...

Or we could use the default options only if there is no options specified when it is being mount, but it will make the default options useless.

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

Signed-off-by Hidetoshi Seto <[email protected]>

---
 Makefile             |    5 +-
 btrfs-parse-mntopt.c |  111 +++++++++++++++++++++++++++++++++++++
 btrfs-parse-mntopt.h |   65 ++++++++++++++++++++++
 btrfs.c              |    1 +
 cmds-mount.c         |  150 ++++++++++++++++++++++++++++++++++++++++++++++++++
 commands.h           |    2 +
 ctree.h              |   41 +++++++++++++-
 7 files changed, 372 insertions(+), 3 deletions(-)
 create mode 100644 btrfs-parse-mntopt.c
 create mode 100644 btrfs-parse-mntopt.h
 create mode 100644 cmds-mount.c

Makefile +3 -2

index c0aaa3d..6f67f4c 100644
@@ -5,9 +5,10 @@ objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
 	  root-tree.o dir-item.o file-item.o inode-item.o \
 	  inode-map.o crc32c.o rbtree.o extent-cache.o extent_io.o \
 	  volumes.o utils.o btrfs-list.o btrfslabel.o repair.o \
-	  send-stream.o send-utils.o
+	  send-stream.o send-utils.o btrfs-parse-mntopt.o
 cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
-	       cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o
+	       cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
+	       cmds-mount.o
 
 CHECKFLAGS= -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise \
 	    -Wuninitialized -Wshadow -Wundef

btrfs-parse-mntopt.c new file +111 -0

new file mode 100644
index 0000000..87b341c
@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "ctree.h"
+#include "btrfs-parse-mntopt.h"
+
+void btrfs_parse_string2mntopt(struct btrfs_root *root, char **options)
+{
+	struct btrfs_super_block *sb = &root->fs_info->super_copy;
+	char *p = NULL;
+	int i = 0;
+
+	memset(&sb->default_mount_opt, 0, sizeof(unsigned long));
+	while ((p = strsep(options, ",")) != NULL) {
+		int token = DEF_MNTOPT_NUM + 1;
+
+		if (!*p)
+			continue;
+		for (i = 0; i < DEF_MNTOPT_NUM; i++) {
+			if (!strcmp(p, toke[i].pattern)) {
+				token = toke[i].token;
+				break;
+			}
+		}
+		if (token > DEF_MNTOPT_NUM) {
+			printf("error: %s\n", p);
+			return;
+		}
+
+		switch (token) {
+		case Opt_degraded:
+			btrfs_set_opt(sb->default_mount_opt, DEGRADED);
+			break;
+
+		case Opt_nodatasum:
+			btrfs_set_opt(sb->default_mount_opt, NODATASUM);
+			break;
+		case Opt_nodatacow:
+			btrfs_set_opt(sb->default_mount_opt, NODATACOW);
+			btrfs_set_opt(sb->default_mount_opt, NODATASUM);
+			break;
+		case Opt_ssd:
+			btrfs_set_opt(sb->default_mount_opt, SSD);
+			break;
+		case Opt_ssd_spread:
+			btrfs_set_opt(sb->default_mount_opt, SSD);
+			btrfs_set_opt(sb->default_mount_opt, SSD_SPREAD);
+			break;
+		case Opt_nossd:
+			btrfs_set_opt(sb->default_mount_opt, NOSSD);
+			btrfs_clear_opt(sb->default_mount_opt, SSD);
+			btrfs_clear_opt(sb->default_mount_opt, SSD_SPREAD);
+			break;
+		case Opt_nobarrier:
+			btrfs_set_opt(sb->default_mount_opt, NOBARRIER);
+			break;
+		case Opt_notreelog:
+			btrfs_set_opt(sb->default_mount_opt, NOTREELOG);
+			break;
+		case Opt_flushoncommit:
+			btrfs_set_opt(sb->default_mount_opt, FLUSHONCOMMIT);
+			break;
+		case Opt_discard:
+			btrfs_set_opt(sb->default_mount_opt, DISCARD);
+			break;
+		case Opt_space_cache:
+			btrfs_set_opt(sb->default_mount_opt, SPACE_CACHE);
+			break;
+		case Opt_no_space_cache:
+			btrfs_clear_opt(sb->default_mount_opt, SPACE_CACHE);
+			break;
+		case Opt_inode_cache:
+			btrfs_set_opt(sb->default_mount_opt, INODE_MAP_CACHE);
+			break;
+		case Opt_clear_cache:
+			btrfs_set_opt(sb->default_mount_opt, CLEAR_CACHE);
+			break;
+		case Opt_user_subvol_rm_allowed:
+			btrfs_set_opt(sb->default_mount_opt,
+					USER_SUBVOL_RM_ALLOWED);
+			break;
+		case Opt_enospc_debug:
+			btrfs_set_opt(sb->default_mount_opt, ENOSPC_DEBUG);
+			break;
+		case Opt_defrag:
+			btrfs_set_opt(sb->default_mount_opt, AUTO_DEFRAG);
+			break;
+		case Opt_recovery:
+			btrfs_set_opt(sb->default_mount_opt, RECOVERY);
+			break;
+		case Opt_skip_balance:
+			btrfs_set_opt(sb->default_mount_opt, SKIP_BALANCE);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+void btrfs_parse_mntopt2string(unsigned long def_opt)
+{
+	if (!def_opt)
+		printf("no default options\n");
+	else {
+		int i = 0;
+		for (i = 0; i < DEF_MNTOPT_NUM; i++) {
+			if (def_opt & (1 << toke[i].token))
+				printf("%s\n", toke[i].pattern);
+		}
+	}
+}

btrfs-parse-mntopt.h new file +65 -0

new file mode 100644
index 0000000..a2745ee
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+struct match_token {
+	int token;
+	const char *pattern;
+};
+
+typedef struct match_token match_table_t[];
+
+enum {
+	Opt_nodatasum, Opt_nodatacow, Opt_nobarrier, Opt_ssd,
+	Opt_degraded, Opt_compress, Opt_notreelog, Opt_flushoncommit,
+	Opt_ssd_spread, Opt_nossd, Opt_discard, Opt_compress_force,
+	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
+	Opt_enospc_debug, Opt_defrag, Opt_inode_cache, Opt_recovery,
+	Opt_skip_balance, Opt_check_integrity,
+	Opt_check_integrity_including_extent_data, Opt_fatal_errors,
+	Opt_no_space_cache, DEF_MNTOPT_NUM,
+};
+
+static match_table_t toke = {
+	{Opt_degraded, "degraded"},
+	{Opt_nodatasum, "nodatasum"},
+	{Opt_nodatacow, "nodatacow"},
+	{Opt_nobarrier, "nobarrier"},
+	{Opt_compress, "compress"},
+	{Opt_compress_force, "compress-force"},
+	{Opt_ssd, "ssd"},
+	{Opt_ssd_spread, "ssd_spread"},
+	{Opt_nossd, "nossd"},
+	{Opt_notreelog, "notreelog"},
+	{Opt_flushoncommit, "flushoncommit"},
+	{Opt_discard, "discard"},
+	{Opt_space_cache, "space_cache"},
+	{Opt_no_space_cache, "no_space_cache"},
+	{Opt_clear_cache, "clear_cache"},
+	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
+	{Opt_enospc_debug, "enospc_debug"},
+	{Opt_defrag, "auto_defrag"},
+	{Opt_inode_cache, "inode_map_cache"},
+	{Opt_recovery, "recovery"},
+	{Opt_skip_balance, "skip_balance"},
+	{Opt_check_integrity, "check_int"},
+	{Opt_check_integrity_including_extent_data, "check_int_data"},
+	{Opt_fatal_errors, "fatal_errors"},
+};
+
+void btrfs_parse_string2mntopt(struct btrfs_root *root, char **options);
+void btrfs_parse_mntopt2string(unsigned long def_opt);

btrfs.c +1 -0

index e9d54f8..0d6c9a7 100644
@@ -246,6 +246,7 @@ const struct cmd_group btrfs_cmd_group = {
 		{ "device", cmd_device, NULL, &device_cmd_group, 0 },
 		{ "scrub", cmd_scrub, NULL, &scrub_cmd_group, 0 },
 		{ "inspect-internal", cmd_inspect, NULL, &inspect_cmd_group, 0 },
+		{ "mount-option", cmd_mount, NULL, &mount_cmd_group, 0 },
 		{ "send", cmd_send, NULL, &send_cmd_group, 0 },
 		{ "receive", cmd_receive, NULL, &receive_cmd_group, 0 },
 		{ "help", cmd_help, cmd_help_usage, NULL, 0 },

cmds-mount.c new file +150 -0

new file mode 100644
index 0000000..cbdb006
@@ -0,0 +1,150 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include "ioctl.h"
+#include "ctree.h"
+#include "transaction.h"
+#include "commands.h"
+#include "disk-io.h"
+#include "utils.h"
+#include "btrfs-parse-mntopt.h"
+
+static const char * const mount_cmd_group_usage[] = {
+	"btrfs mount-option <command> [<args>]",
+	NULL
+};
+
+static const char * const cmd_set_mntopt_usage[] = {
+	"btrfs mount-option set [<option>,...] <device>",
+	"Set default mount options",
+	NULL
+};
+
+static int cmd_set_mntopt(int argc, char **argv)
+{
+	struct btrfs_root *root = NULL;
+	struct btrfs_trans_handle *trans = NULL;
+	int ret = 0;
+
+	if (argc != 3)
+		usage(cmd_set_mntopt_usage);
+
+	if (check_mounted(argv[argc - 1])) {
+		fprintf(stderr, "%s is mounted\n", argv[argc - 1]);
+		return 1;
+	}
+
+	root = open_ctree(argv[argc - 1], 0, 1);
+
+	if (!root)
+		printf("error root\n");
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_parse_string2mntopt(root, &argv[1]);
+	ret = btrfs_commit_transaction(trans, root);
+
+	close_ctree(root);
+	return ret;
+};
+
+static const char * const cmd_get_mntopt_usage[] = {
+	"btrfs mount-option get <device>",
+	"Get default mount options",
+	NULL
+};
+
+static int cmd_get_mntopt(int argc, char **argv)
+{
+	struct btrfs_root *root = NULL;
+	unsigned long def_opt;
+
+	memset(&def_opt, 0, sizeof(def_opt));
+	if (argc != 2) {
+		usage(cmd_get_mntopt_usage);
+		return 1;
+	}
+
+	if (check_mounted(argv[argc - 1])) {
+		fprintf(stderr, "%s is mounted\n", argv[argc - 1]);
+		return 1;
+	}
+
+	root = open_ctree(argv[argc - 1], 0, 0);
+
+	if (!root) {
+		printf("error root\n");
+		return 1;
+	}
+
+	def_opt = btrfs_super_default_mount_opt(&root->fs_info->super_copy);
+
+	btrfs_parse_mntopt2string(def_opt);
+
+	close_ctree(root);
+	return 0;
+};
+
+static const char * const cmd_clear_mntopt_usage[] = {
+	"btrfs mount-option clear <device>",
+	"Clear default mount options",
+	NULL
+};
+
+static int cmd_clear_mntopt(int argc, char **argv)
+{
+	struct btrfs_root *root = NULL;
+	struct btrfs_trans_handle *trans = NULL;
+	int ret = 0;
+
+	if (argc != 2) {
+		usage(cmd_clear_mntopt_usage);
+		return 1;
+	}
+
+	if (check_mounted(argv[argc - 1])) {
+		fprintf(stderr, "%s is mounted\n", argv[argc - 1]);
+		return 1;
+	}
+
+	root = open_ctree(argv[argc - 1], 0, 1);
+
+	if (!root)
+		printf("error root\n");
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_super_default_mount_opt(&root->fs_info->super_copy, 0);
+	ret = btrfs_commit_transaction(trans, root);
+
+	close_ctree(root);
+	return ret;
+};
+
+const struct cmd_group mount_cmd_group = {
+	mount_cmd_group_usage, NULL, {
+		{ "set", cmd_set_mntopt, cmd_set_mntopt_usage, NULL, 0 },
+		{ "get", cmd_get_mntopt, cmd_get_mntopt_usage, NULL, 0 },
+		{ "clear", cmd_clear_mntopt, cmd_clear_mntopt_usage, NULL, 0},
+		{0, 0, 0, 0, 0 }
+	}
+};
+
+int cmd_mount(int argc, char **argv)
+{
+	return handle_command_group(&mount_cmd_group, argc, argv);
+}

commands.h +2 -0

index 1ece87a..6cf91fc 100644
@@ -88,6 +88,7 @@ extern const struct cmd_group balance_cmd_group;
 extern const struct cmd_group device_cmd_group;
 extern const struct cmd_group scrub_cmd_group;
 extern const struct cmd_group inspect_cmd_group;
+extern const struct cmd_group mount_cmd_group;
 extern const struct cmd_group send_cmd_group;
 extern const struct cmd_group receive_cmd_group;
 

@@ -97,5 +98,6 @@ int cmd_balance(int argc, char **argv);
 int cmd_device(int argc, char **argv);
 int cmd_scrub(int argc, char **argv);
 int cmd_inspect(int argc, char **argv);
+int cmd_mount(int argc, char **argv);
 int cmd_send(int argc, char **argv);
 int cmd_receive(int argc, char **argv);

ctree.h +40 -1

index d218b88..4a1bb5b 100644
@@ -401,8 +401,11 @@ struct btrfs_super_block {
 
 	__le64 cache_generation;
 
+	/* default mount options */
+	unsigned long default_mount_opt;
+
 	/* future expansion */
-	__le64 reserved[31];
+	__le64 reserved[30];
 	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
 	struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
 } __attribute__ ((__packed__));

@@ -1774,6 +1777,8 @@ BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block,
 			 csum_type, 16);
 BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block,
 			 cache_generation, 64);
+BTRFS_SETGET_STACK_FUNCS(super_default_mount_opt, struct btrfs_super_block,
+			 default_mount_opt, 64);
 
 static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
 {

@@ -2128,3 +2133,37 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, struct btrfs_path *path,
 			u64 isize);
 #endif
+
+/*
+ * Flags for mount options.
+ *
+ * Note: don't forget to add new options to btrfs_show_options()
+ */
+#define BTRFS_MOUNT_NODATASUM		(1 << 0)
+#define BTRFS_MOUNT_NODATACOW		(1 << 1)
+#define BTRFS_MOUNT_NOBARRIER		(1 << 2)
+#define BTRFS_MOUNT_SSD			(1 << 3)
+#define BTRFS_MOUNT_DEGRADED		(1 << 4)
+#define BTRFS_MOUNT_COMPRESS		(1 << 5)
+#define BTRFS_MOUNT_NOTREELOG           (1 << 6)
+#define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)
+#define BTRFS_MOUNT_SSD_SPREAD		(1 << 8)
+#define BTRFS_MOUNT_NOSSD		(1 << 9)
+#define BTRFS_MOUNT_DISCARD		(1 << 10)
+#define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
+#define BTRFS_MOUNT_SPACE_CACHE		(1 << 12)
+#define BTRFS_MOUNT_CLEAR_CACHE		(1 << 13)
+#define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
+#define BTRFS_MOUNT_ENOSPC_DEBUG	 (1 << 15)
+#define BTRFS_MOUNT_AUTO_DEFRAG		(1 << 16)
+#define BTRFS_MOUNT_INODE_MAP_CACHE	(1 << 17)
+#define BTRFS_MOUNT_RECOVERY		(1 << 18)
+#define BTRFS_MOUNT_SKIP_BALANCE	(1 << 19)
+#define BTRFS_MOUNT_CHECK_INTEGRITY	(1 << 20)
+#define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
+#define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR	(1 << 22)
+
+#define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
+#define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
+#define btrfs_test_opt(root, opt)	((root)->fs_info->mount_opt& \
+					 BTRFS_MOUNT_##opt)

Quoted 5 lines · Hidetoshi Seto

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

I don't think we need implement a separate command to do this, we can add it into btrfstune just like ext3/4. If so, the users who used ext3/4 before can be familiar with btrfs command as soon as possible.

Quoted 11 lines · On Tue, 18 Sep 2012 10:31:41 +0800 Miao Xie <[email protected]> wrote:

Quoted 5 lines · Hidetoshi Seto

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

I don't think we need implement a separate command to do this, we can add it into btrfstune just like ext3/4. If so, the users who used ext3/4 before can be familiar with btrfs command as soon as possible.

btrfstune currently only does one thing:

$ sudo btrfstune
usage: btrfstune [options] device
	-S value	enable/disable seeding

To me it'd seem more logical the other way, why not move this operation to the base "btrfs" utility under some command, and remove "btrfstune" completely.

Quoted 21 lines · Roman Mamedov

Quoted 11 lines · On Tue, 18 Sep 2012 10:31:41 +0800 Miao Xie <[email protected]> wrote:

Quoted 5 lines · Hidetoshi Seto

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

I don't think we need implement a separate command to do this, we can add it into btrfstune just like ext3/4. If so, the users who used ext3/4 before can be familiar with btrfs command as soon as possible.

btrfstune currently only does one thing:

$ sudo btrfstune
usage: btrfstune [options] device
	-S value	enable/disable seeding

Quoted 2 lines

To me it'd seem more logical the other way, why not move this operation to the base "btrfs" utility under some command, and remove "btrfstune" completely.

I would suggest picking up and extending Alex Block's "btrfs
property set/get" idea for this.

Quoted 5 lines · Hidetoshi Seto

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

I don't think we need implement a separate command to do this, we can add it into btrfstune just like ext3/4. If so, the users who used ext3/4 before can be familiar with btrfs command as soon as possible.

Beside that, why not add a option into mkfs.btrfs?

Quoted 11 lines · Miao Xie

Quoted 5 lines · Hidetoshi Seto

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

I don't think we need implement a separate command to do this, we can add it into btrfstune just like ext3/4. If so, the users who used ext3/4 before can be familiar with btrfs command as soon as possible.

As some people already pointed out, I also think that the btrfstune command is a kind of obsolete, and therefore it would be better to improve the btrfs command as centralized utility.

Quoted 1 line

Quoted 1 line

Beside that, why not add a option into mkfs.btrfs?

It is planned. Once we can fix a way how to save default options, modifying mkfs.btfs would be easy.

Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

cmds-mount.c new file +7 -0

+	}
+};
+
+int cmd_mount(int argc, char **argv)
+{
+	return handle_command_group(&mount_cmd_group, argc, argv);
+}

commands.h +2 -0

index 1ece87a..6cf91fc 100644
@@ -88,6 +88,7 @@ extern const struct cmd_group balance_cmd_group;
 extern const struct cmd_group device_cmd_group;
 extern const struct cmd_group scrub_cmd_group;
 extern const struct cmd_group inspect_cmd_group;
+extern const struct cmd_group mount_cmd_group;
 extern const struct cmd_group send_cmd_group;
 extern const struct cmd_group receive_cmd_group;
 

@@ -97,5 +98,6 @@ int cmd_balance(int argc, char **argv);
 int cmd_device(int argc, char **argv);
 int cmd_scrub(int argc, char **argv);
 int cmd_inspect(int argc, char **argv);
+int cmd_mount(int argc, char **argv);
 int cmd_send(int argc, char **argv);
 int cmd_receive(int argc, char **argv);

ctree.h +0 -0

index d218b88..4a1bb5b 100644

ctree.h +4 -1

+
 	/* future expansion */
-	__le64 reserved[31];
+	__le64 reserved[30];
 	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
 	struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
 } __attribute__ ((__packed__));

@@ -1774,6 +1777,8 @@ BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block,
 			 csum_type, 16);
 BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block,
 			 cache_generation, 64);
+BTRFS_SETGET_STACK_FUNCS(super_default_mount_opt, struct btrfs_super_block,
+			 default_mount_opt, 64);
 
 static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
 {

On Tue, Sep 18, 2012 at 10:30:17AM +0900, Hidetoshi Seto wrote:

So, you're basically implementing subset of the whole-filesystem options. As has been mentioned, alternate way is to use the 'properties' interface as a global entry point from the management tool. It would be great if you base your patches on top of it.

(The props haven't been acked, but we've reached a wider consensus on irc, patches are in the mailinglist, so we can bring it up again and discuss outstanding issues or objections. I'm mainly concerned about priority of setting the defaults and not-bloating the 'btrfs' interface too much.)

----Messaggio originale----
Da: [email protected]
Data: 18/09/2012 3.30
A: <[email protected]>
Ogg: [PATCH 2/2] Btrfs-progs: add mount-option command

(quoted diff) +23 -0

+/*
+ * Flags for mount options.
+ *
+ * Note: don't forget to add new options to btrfs_show_options()
+ */
+#define BTRFS_MOUNT_NODATASUM		(1 << 0)
+#define BTRFS_MOUNT_NODATACOW		(1 << 1)
+#define BTRFS_MOUNT_NOBARRIER		(1 << 2)
+#define BTRFS_MOUNT_SSD			(1 << 3)
+#define BTRFS_MOUNT_DEGRADED		(1 << 4)
+#define BTRFS_MOUNT_COMPRESS		(1 << 5)
+#define BTRFS_MOUNT_NOTREELOG           (1 << 6)
+#define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)
+#define BTRFS_MOUNT_SSD_SPREAD		(1 << 8)
+#define BTRFS_MOUNT_NOSSD		(1 << 9)
+#define BTRFS_MOUNT_DISCARD		(1 << 10)
+#define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
+#define BTRFS_MOUNT_SPACE_CACHE		(1 << 12)
+#define BTRFS_MOUNT_CLEAR_CACHE		(1 << 13)
+#define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
+#define BTRFS_MOUNT_ENOSPC_DEBUG	 (1 << 15)
+#define BTRFS_MOUNT_AUTO_DEFRAG		(1 << 16)
+#define BTRFS_MOUNT_INODE_MAP_CACHE	(1 << 17)

Signature · 7 lines

1.7.7.6


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Hi Seto,

please could you update also the man page too ?

Why it was not provided a way to clear a *single* flag ? To me it seems a bit too long to clear all the flag (btrfs mount-option clear) and then set the right one.

As user interface I suggest something like chmod:

btrfs mount-option set +ssd,skip_balance -nodatacow /dev/sdX

or

btrfs mount-option set =ssd,skip_balance,nodatacow /dev/sdX

Finally I have some small concern about two macro (see below)

Quoted 6 lines

----Messaggio originale----
Da: [email protected]
Data: 18/09/2012 3.30
A: <[email protected]>
Ogg: [PATCH 2/2] Btrfs-progs: add mount-option command

[...]

Quoted 23 lines

(quoted diff) +23 -0

+/*
+ * Flags for mount options.
+ *
+ * Note: don't forget to add new options to btrfs_show_options()
+ */
+#define BTRFS_MOUNT_NODATASUM		(1 << 0)
+#define BTRFS_MOUNT_NODATACOW		(1 << 1)
+#define BTRFS_MOUNT_NOBARRIER		(1 << 2)
+#define BTRFS_MOUNT_SSD			(1 << 3)
+#define BTRFS_MOUNT_DEGRADED		(1 << 4)
+#define BTRFS_MOUNT_COMPRESS		(1 << 5)
+#define BTRFS_MOUNT_NOTREELOG           (1 << 6)
+#define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)
+#define BTRFS_MOUNT_SSD_SPREAD		(1 << 8)
+#define BTRFS_MOUNT_NOSSD		(1 << 9)
+#define BTRFS_MOUNT_DISCARD		(1 << 10)
+#define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
+#define BTRFS_MOUNT_SPACE_CACHE		(1 << 12)
+#define BTRFS_MOUNT_CLEAR_CACHE		(1 << 13)
+#define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
+#define BTRFS_MOUNT_ENOSPC_DEBUG	 (1 << 15)
+#define BTRFS_MOUNT_AUTO_DEFRAG		(1 << 16)
+#define BTRFS_MOUNT_INODE_MAP_CACHE	(1 << 17)

Review

Quoted 10 lines

(quoted diff) +10 -0

+#define BTRFS_MOUNT_RECOVERY		(1 << 18)
+#define BTRFS_MOUNT_SKIP_BALANCE	(1 << 19)
+#define BTRFS_MOUNT_CHECK_INTEGRITY	(1 << 20)
+#define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
+#define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR	(1 << 22)
+
+#define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
+#define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
+#define btrfs_test_opt(root, opt)	((root)->fs_info->mount_opt& \
+					 BTRFS_MOUNT_##opt)

I think that the macro names are too generic, I suggest to rename the three macros above as

#define btrfs_mount_XXXX_opt

Also, the last one should be

#define btrfs_test_opt(o, opt) ( o & BTRFS_MOUNT_##opt)

Or better the other two

#define btrfs_mount_clear_opt(root, opt) (((root)->fs_info->mount_opt) &=
~BTRFS_MOUNT_##opt)
#define btrfs_mount_set_opt(root, opt) (((root)->fs_info->mount_opt) |=
BTRFS_MOUNT_##opt)

Why it was not provided a way to clear a *single* flag ? To me it seems a bit too long to clear all the flag (btrfs mount-option clear) and then set the right one.

As user interface I suggest something like chmod:

btrfs mount-option set +ssd,skip_balance -nodatacow /dev/sdX

or

btrfs mount-option set =ssd,skip_balance,nodatacow /dev/sdX

Da: [email protected]
Data: 18/09/2012 6.19
A: <[email protected]>
Cc: "Hidetoshi Seto"<[email protected]>, <[email protected].

Ogg: Re: [PATCH 2/2] Btrfs-progs: add mount-option command

Quoted 11 lines · On Tue, 18 Sep 2012 10:31:41 +0800 Miao Xie <[email protected]> wrote:

Quoted 5 lines · Hidetoshi Seto

This patch adds mount-option command.
The command can set/get default mount options. Now, the command can set/get 24 options. These options are equal to mount options which store in fs_info/mount-opt.

I don't think we need implement a separate command to do this, we can add it into btrfstune just like ext3/4. If so, the users who used ext3/4 before can be familiar with btrfs command as soon as possible.

btrfstune currently only does one thing:

$ sudo btrfstune
usage: btrfstune [options] device
	-S value	enable/disable seeding

To me it'd seem more logical the other way, why not move this operation to

base "btrfs" utility under some command, and remove "btrfstune" completely.

Signature · 9 lines

-- 
With respect,
Roman

~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Stallman had a printer,
with code he could not see.
So he began to tinker,
and set the software free."