Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932500AbWCMWNw (ORCPT ); Mon, 13 Mar 2006 17:13:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932499AbWCMWNw (ORCPT ); Mon, 13 Mar 2006 17:13:52 -0500 Received: from mx1.redhat.com ([66.187.233.31]:50630 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932495AbWCMWNu (ORCPT ); Mon, 13 Mar 2006 17:13:50 -0500 Message-ID: <4415EEFD.6010002@ce.jp.nec.com> Date: Mon, 13 Mar 2006 17:15:25 -0500 From: "Jun'ichi Nomura" User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton , Alasdair Kergon , Greg KH , Neil Brown CC: Lars Marowsky-Bree , device-mapper development , linux-kernel@vger.kernel.org Subject: [PATCH 3/7] dm/md dependency tree in sysfs: bd_claim_by_kobject References: <4415EC4B.4010003@ce.jp.nec.com> In-Reply-To: <4415EC4B.4010003@ce.jp.nec.com> Content-Type: multipart/mixed; boundary="------------080009020706080400080500" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7624 Lines: 282 This is a multi-part message in MIME format. --------------080009020706080400080500 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit This patch is part of dm/md dependency tree in sysfs. This adds bd_claim_by_kobject() function which takes kobject as additional signature of holder device and creates sysfs symlinks between holder device and claimed device. bd_release_from_kobject() is a counter part of bd_claim_by_kobject. Thanks, -- Jun'ichi Nomura, NEC Solutions (America), Inc. --------------080009020706080400080500 Content-Type: text/x-patch; name="03-bd_claim_by_kobj.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="03-bd_claim_by_kobj.patch" Adding bd_claim_by_kobject() function which takes kobject as additional signature of holder device and creates sysfs symlinks between holder device and claimed device. bd_release_from_kobject() is a counter part of bd_claim_by_kobject. Signed-off-by: Jun'ichi Nomura fs/block_dev.c | 206 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 3 2 files changed, 209 insertions(+) --- linux-2.6.16-rc6.orig/include/linux/fs.h 2006-03-11 17:12:55.000000000 -0500 +++ linux-2.6.16-rc6/include/linux/fs.h 2006-03-13 11:24:18.000000000 -0500 @@ -402,6 +402,7 @@ struct block_device { struct list_head bd_inodes; void * bd_holder; int bd_holders; + struct list_head bd_holder_list; struct block_device * bd_contains; unsigned bd_block_size; struct hd_struct * bd_part; @@ -1381,6 +1382,8 @@ extern int blkdev_get(struct block_devic extern int blkdev_put(struct block_device *); extern int bd_claim(struct block_device *, void *); extern void bd_release(struct block_device *); +extern int bd_claim_by_kobject(struct block_device *, void *, struct kobject *); +extern void bd_release_from_kobject(struct block_device *, struct kobject *); /* fs/char_dev.c */ extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *); --- linux-2.6.16-rc6.orig/fs/block_dev.c 2006-03-11 17:12:55.000000000 -0500 +++ linux-2.6.16-rc6/fs/block_dev.c 2006-03-13 11:24:18.000000000 -0500 @@ -269,6 +269,7 @@ static void init_once(void * foo, kmem_c sema_init(&bdev->bd_mount_sem, 1); INIT_LIST_HEAD(&bdev->bd_inodes); INIT_LIST_HEAD(&bdev->bd_list); + INIT_LIST_HEAD(&bdev->bd_holder_list); inode_init_once(&ei->vfs_inode); } } @@ -493,6 +494,211 @@ void bd_release(struct block_device *bde EXPORT_SYMBOL(bd_release); /* + * Functions for bd_claim_by_kobject / bd_release_from_kobject + * + * If a kobject is passed to bd_claim_by_kobject() + * and the kobject has a parent directory, + * following symlinks are created: + * o from the kobject to the claimed bdev + * o from "holders" directory of the bdev to the parent of the kobject + * bd_release_from_kobject() removes these symlinks. + * + * Example: + * If /dev/dm-0 maps to /dev/sda, kobject corresponding to + * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: + * /sys/block/dm-0/slaves/sda --> /sys/block/sda + * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 + */ + + +static inline struct kobject * bdev_get_kobj(struct block_device *bdev) +{ + if (bdev->bd_contains != bdev) + return kobject_get(&bdev->bd_part->kobj); + else + return kobject_get(&bdev->bd_disk->kobj); +} + +static inline struct kobject * bdev_get_holder(struct block_device *bdev) +{ + if (bdev->bd_contains != bdev) + return kobject_get(bdev->bd_part->holder_dir); + else + return kobject_get(bdev->bd_disk->holder_dir); +} + +static inline void add_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + sysfs_create_link(from, to, kobject_name(to)); +} + +static inline void del_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + sysfs_remove_link(from, kobject_name(to)); +} + +/* bd_holder_list is protected by bdev_lock */ +struct bd_holder { + struct list_head list; /* chain of holders of the bdev */ + int count; /* references from the holder */ + struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ + struct kobject *hdev; /* e.g. "/block/dm-0" */ + struct kobject *hdir; /* e.g. "/block/sda/holders" */ + struct kobject *sdev; /* e.g. "/block/sda" */ +}; + +static inline int bd_holder_grab_dirs(struct block_device *bdev, + struct bd_holder *bo) +{ + if (!bdev || !bo) + return 0; + + bo->sdir = kobject_get(bo->sdir); + if (!bo->sdir) + return 0; + + bo->hdev = kobject_get(bo->sdir->parent); + if (!bo->hdev) + goto fail_put_sdir; + + bo->sdev = bdev_get_kobj(bdev); + if (!bo->sdev) + goto fail_put_hdev; + + bo->hdir = bdev_get_holder(bdev); + if (!bo->hdir) + goto fail_put_sdev; + + return 1; + +fail_put_sdev: + kobject_put(bo->sdev); +fail_put_hdev: + kobject_put(bo->hdev); +fail_put_sdir: + kobject_put(bo->sdir); + + return 0; +} + +static inline void bd_holder_release_dirs(struct bd_holder *bo) +{ + kobject_put(bo->hdir); + kobject_put(bo->sdev); + kobject_put(bo->hdev); + kobject_put(bo->sdir); +} + +static struct bd_holder *alloc_bd_holder(struct kobject *kobj) +{ + struct bd_holder *bo; + + bo = kzalloc(sizeof(*bo), GFP_KERNEL); + if (!bo) + return NULL; + + bo->count = 1; + bo->sdir = kobj; + + return bo; +} + +static void free_bd_holder(struct bd_holder *bo) +{ + kfree(bo); +} + +static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) +{ + struct bd_holder *tmp; + + if (!bo) + return 0; + + list_for_each_entry(tmp, &bdev->bd_holder_list, list) { + if (tmp->sdir == bo->sdir) { + tmp->count++; + return 0; + } + } + + if (!bd_holder_grab_dirs(bdev, bo)) + return 0; + + add_symlink(bo->sdir, bo->sdev); + add_symlink(bo->hdir, bo->hdev); + list_add_tail(&bo->list, &bdev->bd_holder_list); + return 1; +} + +static struct bd_holder *del_bd_holder(struct block_device *bdev, + struct kobject *kobj) +{ + struct bd_holder *bo; + + list_for_each_entry(bo, &bdev->bd_holder_list, list) { + if (bo->sdir == kobj) { + bo->count--; + BUG_ON(bo->count < 0); + if (!bo->count) { + list_del(&bo->list); + del_symlink(bo->sdir, bo->sdev); + del_symlink(bo->hdir, bo->hdev); + bd_holder_release_dirs(bo); + return bo; + } + break; + } + } + + return NULL; +} + +int bd_claim_by_kobject(struct block_device *bdev, void *holder, + struct kobject *kobj) +{ + int res = -EBUSY; + struct bd_holder *bo; + + if (!kobj) + return -EINVAL; + + bo = alloc_bd_holder(kobj); + if (!bo) + return -ENOMEM; + + down(&bdev->bd_sem); + res = bd_claim(bdev, holder); + if (res || !add_bd_holder(bdev, bo)) + free_bd_holder(bo); + up(&bdev->bd_sem); + + return res; +} + +EXPORT_SYMBOL(bd_claim_by_kobject); + +void bd_release_from_kobject(struct block_device *bdev, struct kobject *kobj) +{ + struct bd_holder *bo; + + if (!kobj) + return; + + down(&bdev->bd_sem); + bd_release(bdev); + if ((bo = del_bd_holder(bdev, kobj))) + free_bd_holder(bo); + up(&bdev->bd_sem); +} + +EXPORT_SYMBOL(bd_release_from_kobject); + +/* * Tries to open block device by device number. Use it ONLY if you * really do not have anything better - i.e. when you are behind a * truly sucky interface and all you are given is a device number. _Never_ --------------080009020706080400080500-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/