From: Lukas Czerner Subject: [PATCH 6/6] Add interface to advertise ext4 features in sysfs Date: Wed, 15 Sep 2010 18:36:08 +0200 Message-ID: <1284568568-13637-7-git-send-email-lczerner@redhat.com> References: <1284568568-13637-1-git-send-email-lczerner@redhat.com> Cc: tytso@mit.edu, rwheeler@redhat.com, sandeen@redhat.com, adilger@dilger.ca, lczerner@redhat.com To: linux-ext4@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45389 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751942Ab0IOQgg (ORCPT ); Wed, 15 Sep 2010 12:36:36 -0400 In-Reply-To: <1284568568-13637-1-git-send-email-lczerner@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: User-space should have the opportunity to check what features doest ext4 support in each particular copy. This adds easy interface by creating new "features" directory in sys/fs/ext4/. In that directory files advertising feature names can be created. Add lazy_itable_init to the feature list. Signed-off-by: Lukas Czerner --- fs/ext4/ext4.h | 5 +++++ fs/ext4/super.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 54 insertions(+), 1 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 0df3977..9ecac2e 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1502,6 +1502,11 @@ struct ext4_li_request { unsigned long lr_next_sched; }; +struct ext4_features { + struct kobject f_kobj; + struct completion f_kobj_unregister; +}; + /* * Function prototypes */ diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 3e285eb..b817eba 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -57,6 +57,7 @@ struct proc_dir_entry *ext4_proc_root; static struct kset *ext4_kset; struct ext4_lazy_init *ext4_li_info; struct mutex ext4_li_mtx; +struct ext4_features *ext4_feat; static int ext4_load_journal(struct super_block *, struct ext4_super_block *, unsigned long journal_devnum); @@ -2349,6 +2350,7 @@ static struct ext4_attr ext4_attr_##_name = { \ #define EXT4_ATTR(name, mode, show, store) \ static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store) +#define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL) #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL) #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store) #define EXT4_RW_ATTR_SBI_UI(name, elname) \ @@ -2385,6 +2387,14 @@ static struct attribute *ext4_attrs[] = { NULL, }; +/* Features this copy of ext4 supports */ +EXT4_INFO_ATTR(lazy_itable_init); + +static struct attribute *ext4_feat_attrs[] = { + ATTR_LIST(lazy_itable_init), + NULL, +}; + static ssize_t ext4_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { @@ -2413,7 +2423,6 @@ static void ext4_sb_release(struct kobject *kobj) complete(&sbi->s_kobj_unregister); } - static const struct sysfs_ops ext4_attr_ops = { .show = ext4_attr_show, .store = ext4_attr_store, @@ -2425,6 +2434,17 @@ static struct kobj_type ext4_ktype = { .release = ext4_sb_release, }; +static void ext4_feat_release(struct kobject *kobj) +{ + complete(&ext4_feat->f_kobj_unregister); +} + +static struct kobj_type ext4_feat_ktype = { + .default_attrs = ext4_feat_attrs, + .sysfs_ops = &ext4_attr_ops, + .release = ext4_feat_release, +}; + /* * Check whether this filesystem can be mounted based on * the features present and the RDONLY/RDWR mount requested. @@ -4581,6 +4601,30 @@ static struct file_system_type ext4_fs_type = { .fs_flags = FS_REQUIRES_DEV, }; +int __init ext4_init_feat_adverts(void) +{ + struct ext4_features *ef; + int ret = -ENOMEM; + + ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL); + if (!ef) + goto out; + + ef->f_kobj.kset = ext4_kset; + init_completion(&ef->f_kobj_unregister); + ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL, + "features"); + if (ret) { + kfree(ef); + goto out; + } + + ext4_feat = ef; + ret = 0; +out: + return ret; +} + static int __init init_ext4_fs(void) { int err; @@ -4593,6 +4637,9 @@ static int __init init_ext4_fs(void) if (!ext4_kset) goto out4; ext4_proc_root = proc_mkdir("fs/ext4", NULL); + + err = ext4_init_feat_adverts(); + err = init_ext4_mballoc(); if (err) goto out3; @@ -4621,6 +4668,7 @@ out1: out2: exit_ext4_mballoc(); out3: + kfree(ext4_feat); remove_proc_entry("fs/ext4", NULL); kset_unregister(ext4_kset); out4: -- 1.7.2.2