From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:37356 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753150Ab3JZTYQ (ORCPT ); Sat, 26 Oct 2013 15:24:16 -0400 Message-ID: <526C16D4.2020909@suse.com> Date: Sat, 26 Oct 2013 15:24:04 -0400 From: Jeff Mahoney MIME-Version: 1.0 To: Alex Lyakas Cc: linux-btrfs Subject: Re: [patch 3/7] btrfs: Add per-super attributes to sysfs References: <20130910042408.335071038@suse.com> <20130910043007.783624453@suse.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 10/26/13, 3:00 PM, Alex Lyakas wrote: > Hi Jeff, > > On Tue, Sep 10, 2013 at 7:24 AM, Jeff Mahoney 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 >> --- >> 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? This should be the last reference, but even if it's not, it should be removed from sysfs here. Otherwise, I suppose it's personal preference. The call to kobject_del in kobject_release will also drop a debugging message if kobject debugging is enabled. -Jeff >> + 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) >> >> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > Thanks, > Alex, > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Jeff Mahoney SUSE Labs