This patch publishes information on which features are enabled in the file system on a per-super basis. At this point, it only publishes information on features supported by the file system implementation.
Signed-off-by: Jeff Mahoney <je...@suse.com> --- fs/btrfs/ctree.h | 6 +++ fs/btrfs/sysfs.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++---- fs/btrfs/sysfs.h | 2 - 3 files changed, 110 insertions(+), 8 deletions(-) --- a/fs/btrfs/ctree.h 2013-09-09 21:33:17.560730541 -0400 +++ b/fs/btrfs/ctree.h 2013-09-09 21:34:19.067859674 -0400 @@ -1295,6 +1295,11 @@ struct btrfs_stripe_hash_table { #define BTRFS_STRIPE_HASH_TABLE_BITS 11 +struct btrfs_features { + struct kobject f_kobj; + struct completion f_kobj_unregister; +}; + /* fs_info */ struct reloc_control; struct btrfs_device; @@ -1513,6 +1518,7 @@ struct btrfs_fs_info { struct kobject super_kobj; struct completion kobj_unregister; + struct btrfs_features features; int do_barriers; int closing; int log_root_recovering; --- a/fs/btrfs/sysfs.c 2013-09-09 21:33:17.560730541 -0400 +++ b/fs/btrfs/sysfs.c 2013-09-09 23:03:36.030266481 -0400 @@ -31,11 +31,6 @@ /* /sys/fs/btrfs/ entry */ static struct kset *btrfs_kset; -struct btrfs_features { - struct kobject f_kobj; - struct completion f_kobj_unregister; -}; - struct btrfs_features *btrfs_feat; BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF); @@ -61,6 +56,43 @@ static struct attribute *btrfs_supp_feat NULL }; +static void btrfs_feature_release(struct kobject *kobj) +{ + struct btrfs_features *feat; + feat = container_of(kobj, struct btrfs_features, f_kobj); + complete(&feat->f_kobj_unregister); +} + +static ssize_t btrfs_feat_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct btrfs_fs_info *fs_info; + struct btrfs_super_block *disk_super; + struct btrfs_feature_attr *fa = to_btrfs_feature_attr(attr); + u64 features; + + fs_info = container_of(kobj, struct btrfs_fs_info, features.f_kobj); + disk_super = fs_info->super_copy; + + if (fa->feature_set == FEAT_COMPAT) + features = btrfs_super_compat_flags(disk_super); + else if (fa->feature_set == FEAT_COMPAT_RO) + features = btrfs_super_compat_ro_flags(disk_super); + else + features = btrfs_super_incompat_flags(disk_super); + + return snprintf(buf, PAGE_SIZE, "%u\n", !!(features & fa->feature_bit)); +} + +static const struct sysfs_ops btrfs_feat_attr_ops = { + .show = btrfs_feat_show, +}; + +static struct kobj_type btrfs_feat_ktype = { + .sysfs_ops = &btrfs_feat_attr_ops, + .release = btrfs_feature_release, +}; + static struct attribute *btrfs_attrs[] = { NULL, }; @@ -104,16 +136,80 @@ static struct kobj_type btrfs_ktype = { .release = btrfs_fs_info_release, }; +static u64 get_features(struct btrfs_fs_info *fs_info, + enum btrfs_feature_set set) +{ + struct btrfs_super_block *disk_super = fs_info->super_copy; + if (set == FEAT_COMPAT) + return btrfs_super_compat_flags(disk_super); + else if (set == FEAT_COMPAT_RO) + return btrfs_super_compat_ro_flags(disk_super); + else + return btrfs_super_incompat_flags(disk_super); +} + +static int add_per_fs_features(struct btrfs_fs_info *fs_info) +{ + int i; + for (i = 0; btrfs_supp_feature_attrs[i]; i++) { + struct attribute *attr = btrfs_supp_feature_attrs[i]; + struct btrfs_feature_attr *fa = to_btrfs_feature_attr(attr); + u64 features = get_features(fs_info, fa->feature_set); + int error; + + if (features & fa->feature_bit) { + error = sysfs_create_file(&fs_info->features.f_kobj, + &fa->attr); + if (error) + return error; + } + } + return 0; +} + int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info) { + int error; + init_completion(&fs_info->kobj_unregister); fs_info->super_kobj.kset = btrfs_kset; - return kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL, - "%pU", fs_info->fsid); + error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL, + "%pU", fs_info->fsid); + if (error) + return error; + + init_completion(&fs_info->features.f_kobj_unregister); + error = kobject_init_and_add(&fs_info->features.f_kobj, + &btrfs_feat_ktype, + &fs_info->super_kobj, + "features"); + if (error) + goto out_super; + + error = add_per_fs_features(fs_info); + if (error) + goto out_features; + + return 0; + +out_features: + kobject_del(&fs_info->features.f_kobj); + kobject_put(&fs_info->features.f_kobj); + wait_for_completion(&fs_info->features.f_kobj_unregister); +out_super: + kobject_del(&fs_info->super_kobj); + kobject_put(&fs_info->super_kobj); + wait_for_completion(&fs_info->kobj_unregister); + + return error; } void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info) { + kobject_del(&fs_info->features.f_kobj); + kobject_put(&fs_info->features.f_kobj); + wait_for_completion(&fs_info->features.f_kobj_unregister); + kobject_del(&fs_info->super_kobj); kobject_put(&fs_info->super_kobj); wait_for_completion(&fs_info->kobj_unregister); --- a/fs/btrfs/sysfs.h 2013-09-09 21:33:17.560730541 -0400 +++ b/fs/btrfs/sysfs.h 2013-09-09 22:48:51.634164572 -0400 @@ -27,7 +27,7 @@ static struct btrfs_attr btrfs_attr_##_n __INIT_BTRFS_ATTR(_name, _mode, _show, _store) struct btrfs_feature_attr { - struct attribute attr; /* global show, no store */ + struct attribute attr; /* per-fs/global show, no store */ enum btrfs_feature_set feature_set; u64 feature_bit; }; -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html