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 <jeffm@xxxxxxxx>
---
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;
};
--
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