Hi Jeff,
On Tue, Sep 10, 2013 at 7:24 AM, Jeff Mahoney <jeffm@xxxxxxxx> wrote:
> This patch adds per-super attributes to sysfs.
>
> It doesn't publish any attributes yet, but does the proper lifetime
> handling as well as the basic infrastructure to add new attributes.
>
> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
> ---
> fs/btrfs/ctree.h | 2 +
> fs/btrfs/super.c | 13 +++++++++++-
> fs/btrfs/sysfs.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/sysfs.h | 19 ++++++++++++++++++
> 4 files changed, 91 insertions(+), 1 deletion(-)
>
> --- a/fs/btrfs/ctree.h 2013-09-10 00:09:12.990087784 -0400
> +++ b/fs/btrfs/ctree.h 2013-09-10 00:09:35.521794520 -0400
> @@ -3694,6 +3694,8 @@ int btrfs_defrag_leaves(struct btrfs_tra
> /* sysfs.c */
> int btrfs_init_sysfs(void);
> void btrfs_exit_sysfs(void);
> +int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info);
> +void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info);
>
> /* xattr.c */
> ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
> --- a/fs/btrfs/super.c 2013-09-10 00:09:12.994087730 -0400
> +++ b/fs/btrfs/super.c 2013-09-10 00:09:35.525794464 -0400
> @@ -301,6 +301,8 @@ void __btrfs_panic(struct btrfs_fs_info
>
> static void btrfs_put_super(struct super_block *sb)
> {
> + btrfs_sysfs_remove_one(btrfs_sb(sb));
> +
> (void)close_ctree(btrfs_sb(sb)->tree_root);
> /* FIXME: need to fix VFS to return error? */
> /* AV: return it _where_? ->put_super() can be triggered by any number
> @@ -1143,8 +1145,17 @@ static struct dentry *btrfs_mount(struct
> }
>
> root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
> - if (IS_ERR(root))
> + if (IS_ERR(root)) {
> deactivate_locked_super(s);
> + return root;
> + }
> +
> + error = btrfs_sysfs_add_one(fs_info);
> + if (error) {
> + dput(root);
> + deactivate_locked_super(s);
> + return ERR_PTR(error);
> + }
>
> return root;
>
> --- a/fs/btrfs/sysfs.c 2013-09-10 00:09:13.002087628 -0400
> +++ b/fs/btrfs/sysfs.c 2013-09-10 00:09:49.501616538 -0400
> @@ -61,6 +61,64 @@ static struct attribute *btrfs_supp_feat
> NULL
> };
>
> +static struct attribute *btrfs_attrs[] = {
> + NULL,
> +};
> +
> +static void btrfs_fs_info_release(struct kobject *kobj)
> +{
> + struct btrfs_fs_info *fs_info;
> + fs_info = container_of(kobj, struct btrfs_fs_info, super_kobj);
> + complete(&fs_info->kobj_unregister);
> +}
> +
> +static ssize_t btrfs_attr_show(struct kobject *kobj,
> + struct attribute *attr, char *buf)
> +{
> + struct btrfs_attr *a = container_of(attr, struct btrfs_attr, attr);
> + struct btrfs_fs_info *fs_info;
> + fs_info = container_of(kobj, struct btrfs_fs_info, super_kobj);
> +
> + return a->show ? a->show(a, fs_info, buf) : 0;
> +}
> +
> +static ssize_t btrfs_attr_store(struct kobject *kobj,
> + struct attribute *attr,
> + const char *buf, size_t len)
> +{
> + struct btrfs_attr *a = container_of(attr, struct btrfs_attr, attr);
> + struct btrfs_fs_info *fs_info;
> + fs_info = container_of(kobj, struct btrfs_fs_info, super_kobj);
> +
> + return a->store ? a->store(a, fs_info, buf, len) : 0;
> +}
> +
> +static const struct sysfs_ops btrfs_attr_ops = {
> + .show = btrfs_attr_show,
> + .store = btrfs_attr_store,
> +};
> +
> +static struct kobj_type btrfs_ktype = {
> + .default_attrs = btrfs_attrs,
> + .sysfs_ops = &btrfs_attr_ops,
> + .release = btrfs_fs_info_release,
> +};
> +
> +int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
> +{
> + 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);
> +}
> +
> +void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
> +{
> + kobject_del(&fs_info->super_kobj);
Is there a reason for this explicit call? The last kobject_put will do
this automatically, no?
> + kobject_put(&fs_info->super_kobj);
> + wait_for_completion(&fs_info->kobj_unregister);
> +}
> +
> static void btrfs_supp_feat_release(struct kobject *kobj)
> {
> complete(&btrfs_feat->f_kobj_unregister);
> --- a/fs/btrfs/sysfs.h 2013-09-10 00:09:13.002087628 -0400
> +++ b/fs/btrfs/sysfs.h 2013-09-10 00:09:35.525794464 -0400
> @@ -8,6 +8,24 @@ enum btrfs_feature_set {
> FEAT_MAX
> };
>
> +struct btrfs_attr {
> + struct attribute attr;
> + ssize_t (*show)(struct btrfs_attr *, struct btrfs_fs_info *, char *);
> + ssize_t (*store)(struct btrfs_attr *, struct btrfs_fs_info *,
> + const char *, size_t);
> +};
> +
> +#define __INIT_BTRFS_ATTR(_name, _mode, _show, _store) \
> +{ \
> + .attr = { .name = __stringify(_name), .mode = _mode }, \
> + .show = _show, \
> + .store = _store, \
> +}
> +
> +#define BTRFS_ATTR(_name, _mode, _show, _store) \
> +static struct btrfs_attr btrfs_attr_##_name = \
> + __INIT_BTRFS_ATTR(_name, _mode, _show, _store)
> +
> struct btrfs_feature_attr {
> struct attribute attr; /* global show, no store */
> enum btrfs_feature_set feature_set;
> @@ -31,6 +49,7 @@ static struct btrfs_feature_attr btrfs_a
> #define BTRFS_SUPP_FEAT_LIST(_name) (&btrfs_attr_##_name.attr),
>
> /* convert from attribute */
> +#define to_btrfs_attr(a) container_of(a, struct btrfs_attr, attr)
> #define to_btrfs_feature_attr(a) \
> container_of(a, struct btrfs_feature_attr, attr)
>
>
>
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Thanks,
Alex,
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