From f3623740068e548b7c6fdb42171c118189d0e03f Mon Sep 17 00:00:00 2001 From: Anand Jain Date: Wed, 4 Oct 2023 23:00:27 +0800 Subject: btrfs: sysfs: show temp_fsid feature This adds sysfs objects to indicate temp_fsid feature support and its status. /sys/fs/btrfs/features/temp_fsid /sys/fs/btrfs//temp_fsid For example: Consider two cloned and mounted devices. $ blkid /dev/sdc[1-2] /dev/sdc1: UUID="509ad44b-ad2a-4a8a-bc8d-fe69db7220d5" .. /dev/sdc2: UUID="509ad44b-ad2a-4a8a-bc8d-fe69db7220d5" .. One gets actual fsid, and the other gets the temp_fsid when mounted. $ btrfs filesystem show -m Label: none uuid: 509ad44b-ad2a-4a8a-bc8d-fe69db7220d5 Total devices 1 FS bytes used 54.14MiB devid 1 size 300.00MiB used 144.00MiB path /dev/sdc1 Label: none uuid: 33bad74e-c91b-43a5-aef8-b3cab97ae63a Total devices 1 FS bytes used 54.14MiB devid 1 size 300.00MiB used 144.00MiB path /dev/sdc2 Their sysfs as below. $ cat /sys/fs/btrfs/features/temp_fsid 0 $ cat /sys/fs/btrfs/509ad44b-ad2a-4a8a-bc8d-fe69db7220d5/temp_fsid 0 $ cat /sys/fs/btrfs/33bad74e-c91b-43a5-aef8-b3cab97ae63a/temp_fsid 1 Signed-off-by: Anand Jain Signed-off-by: David Sterba --- fs/btrfs/sysfs.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'fs/btrfs/sysfs.c') diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 21ab8b9b62ce..e6b51fb3ddc1 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -425,6 +425,13 @@ static ssize_t acl_show(struct kobject *kobj, struct kobj_attribute *a, char *bu } BTRFS_ATTR(static_feature, acl, acl_show); +static ssize_t temp_fsid_supported_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + return sysfs_emit(buf, "0\n"); +} +BTRFS_ATTR(static_feature, temp_fsid, temp_fsid_supported_show); + /* * Features which only depend on kernel version. * @@ -438,6 +445,7 @@ static struct attribute *btrfs_supported_static_feature_attrs[] = { BTRFS_ATTR_PTR(static_feature, send_stream_version), BTRFS_ATTR_PTR(static_feature, supported_rescue_options), BTRFS_ATTR_PTR(static_feature, supported_sectorsizes), + BTRFS_ATTR_PTR(static_feature, temp_fsid), NULL }; @@ -1205,6 +1213,15 @@ static ssize_t btrfs_generation_show(struct kobject *kobj, } BTRFS_ATTR(, generation, btrfs_generation_show); +static ssize_t btrfs_temp_fsid_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + struct btrfs_fs_info *fs_info = to_fs_info(kobj); + + return sysfs_emit(buf, "%d\n", fs_info->fs_devices->temp_fsid); +} +BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show); + static const char * const btrfs_read_policy_name[] = { "pid" }; static ssize_t btrfs_read_policy_show(struct kobject *kobj, @@ -1307,6 +1324,7 @@ static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, read_policy), BTRFS_ATTR_PTR(, bg_reclaim_threshold), BTRFS_ATTR_PTR(, commit_stats), + BTRFS_ATTR_PTR(, temp_fsid), NULL, }; -- cgit