From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266006AbUBDLeb (ORCPT ); Wed, 4 Feb 2004 06:34:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266324AbUBDLeb (ORCPT ); Wed, 4 Feb 2004 06:34:31 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.104]:205 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S266006AbUBDLeL (ORCPT ); Wed, 4 Feb 2004 06:34:11 -0500 Date: Wed, 4 Feb 2004 17:08:48 +0530 From: Maneesh Soni To: LKML Cc: Greg KH , Al Viro , Dipankar Sarma , "Martin J. Bligh" , Matt Mackall , Christian Borntraeger Subject: [RFC/T 1/6] sysfs backing store (with symlink) Message-ID: <20040204113848.GB4234@in.ibm.com> Reply-To: maneesh@in.ibm.com References: <20040204113758.GA4234@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040204113758.GA4234@in.ibm.com> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org => changes in this version > added defines for symlinks o The following patch contains the sysfs_dirent structure definition. sysfs_dirent can represent kobject, attribute group, text attribute or binary attribute for kobjects registered with sysfs. sysfs_dirent is allocated with a ref count (s_count) of 1. Ref count is incremented when a dentry is associated with the sysfs_dirent and it is decremented when the corresponding dentry is freed. o sysfs_dirent's corresponding to the attribute files of a kobject or attribute group are linked together with s_sibling and are anchored at s_children of the corresponding kobject's or attribute-group's sysfs_dirent. o The patch also contains the mount related changes for sysfs backing store. Because we mount sysfs once while init(), plain umount of sysfs doesnot free all the un-used dentries (present in LRU list). To use force umount flag, umount_begin() routine is provided which does a shrink_dcache_parent() to release all the unused dentries. fs/sysfs/mount.c | 28 ++++++++++++++++++++++++++-- include/linux/sysfs.h | 19 +++++++++++++++++++ 2 files changed, 45 insertions(+), 2 deletions(-) diff -puN fs/sysfs/mount.c~sysfs-leaves-mount fs/sysfs/mount.c --- linux-2.6.2-rc3/fs/sysfs/mount.c~sysfs-leaves-mount 2004-02-02 21:48:35.000000000 +0530 +++ linux-2.6.2-rc3-maneesh/fs/sysfs/mount.c 2004-02-02 21:50:36.000000000 +0530 @@ -20,6 +20,14 @@ struct super_block * sysfs_sb = NULL; static struct super_operations sysfs_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, + .umount_begin = sysfs_umount_begin, +}; + +struct sysfs_dirent sysfs_root = { + .s_sibling = LIST_HEAD_INIT(sysfs_root.s_sibling), + .s_children = LIST_HEAD_INIT(sysfs_root.s_children), + .s_element = NULL, + .s_type = SYSFS_ROOT, }; static int sysfs_fill_super(struct super_block *sb, void *data, int silent) @@ -35,8 +43,8 @@ static int sysfs_fill_super(struct super inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); if (inode) { - inode->i_op = &simple_dir_inode_operations; - inode->i_fop = &simple_dir_operations; + inode->i_op = &sysfs_dir_inode_operations; + inode->i_fop = &sysfs_dir_operations; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inode->i_nlink++; } else { @@ -50,6 +58,7 @@ static int sysfs_fill_super(struct super iput(inode); return -ENOMEM; } + root->d_fsdata = &sysfs_root; sb->s_root = root; return 0; } @@ -60,6 +69,21 @@ static struct super_block *sysfs_get_sb( return get_sb_single(fs_type, flags, data, sysfs_fill_super); } +/* For freeing zero refenced dentries / inodes while force unmounting + * + * Because still sysfs has dentries corresponding to the directories pinned + * in memory which keeps the super block always active and ->kill_sb is never + * called while unmounting, in order to free the memory used by un-used + * dentries and inodes sysfs has to be "force" umounted. + */ +void sysfs_umount_begin(struct super_block * sb) +{ + lock_super(sb); + if (sb->s_root) + shrink_dcache_parent(sb->s_root); + unlock_super(sb); +} + static struct file_system_type sysfs_fs_type = { .name = "sysfs", .get_sb = sysfs_get_sb, diff -puN include/linux/sysfs.h~sysfs-leaves-mount include/linux/sysfs.h --- linux-2.6.2-rc3/include/linux/sysfs.h~sysfs-leaves-mount 2004-02-02 21:48:42.000000000 +0530 +++ linux-2.6.2-rc3-maneesh/include/linux/sysfs.h 2004-02-02 21:59:56.000000000 +0530 @@ -9,6 +9,8 @@ #ifndef _SYSFS_H_ #define _SYSFS_H_ +#include + struct kobject; struct module; @@ -42,6 +44,23 @@ sysfs_remove_dir(struct kobject *); extern void sysfs_rename_dir(struct kobject *, const char *new_name); +struct sysfs_dirent { + atomic_t s_count; + struct list_head s_sibling; + struct list_head s_children; + void * s_element; + int s_type; + struct dentry * s_dentry; +}; + +#define SYSFS_ROOT 0x0001 +#define SYSFS_KOBJECT 0x0002 +#define SYSFS_KOBJ_ATTR 0x0004 +#define SYSFS_KOBJ_BIN_ATTR 0x0008 +#define SYSFS_KOBJ_ATTR_GROUP 0x0010 +#define SYSFS_KOBJ_LINK 0x0020 +#define SYSFS_NOT_PINNED (SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR | SYSFS_KOBJ_LINK) + extern int sysfs_create_file(struct kobject *, const struct attribute *); _ -- Maneesh Soni Linux Technology Center, IBM Software Lab, Bangalore, India email: maneesh@in.ibm.com Phone: 91-80-5044999 Fax: 91-80-5268553 T/L : 9243696