Messages in this thread Patch in this message | | | Date | Mon, 29 Dec 2003 15:03:54 +0530 | From | Maneesh Soni <> | Subject | [RFC 1/5] sysfs backing store (leaves only) - sysfs-leaves-mount.patch |
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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 | 21 +++++++++++++++++++-- include/linux/sysfs.h | 17 +++++++++++++++++ 2 files changed, 36 insertions(+), 2 deletions(-)
diff -puN include/linux/sysfs.h~sysfs-leaves-mount include/linux/sysfs.h --- linux-2.6.0/include/linux/sysfs.h~sysfs-leaves-mount 2003-12-29 12:50:50.000000000 +0530 +++ linux-2.6.0-maneesh/include/linux/sysfs.h 2003-12-29 12:53:50.000000000 +0530 @@ -9,6 +9,8 @@ #ifndef _SYSFS_H_ #define _SYSFS_H_ +#include <asm/atomic.h> + struct kobject; struct module; @@ -33,6 +35,21 @@ struct sysfs_ops { ssize_t (*store)(struct kobject *,struct attribute *,const char *, size_t); }; +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 + extern int sysfs_create_dir(struct kobject *); diff -puN fs/sysfs/mount.c~sysfs-leaves-mount fs/sysfs/mount.c --- linux-2.6.0/fs/sysfs/mount.c~sysfs-leaves-mount 2003-12-29 12:51:04.000000000 +0530 +++ linux-2.6.0-maneesh/fs/sysfs/mount.c 2003-12-29 12:59:21.000000000 +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 +69,14 @@ static struct super_block *sysfs_get_sb( return get_sb_single(fs_type, flags, data, sysfs_fill_super); } +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, _ -- 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 - 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/
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