51225039f3
This patch makes dentries and inodes for sysfs directories reclaimable. * sysfs_notify() is modified to walk sysfs_dirent tree instead of dentry tree. * sysfs_update_file() and sysfs_chmod_file() use sysfs_get_dentry() to grab the victim dentry. * sysfs_rename_dir() and sysfs_move_dir() grab all dentries using sysfs_get_dentry() on startup. * Dentries for all shadowed directories are pinned in memory to serve as lookup start point. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
112 lines
2.4 KiB
C
112 lines
2.4 KiB
C
/*
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* mount.c - operations for initializing and mounting sysfs.
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*/
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#define DEBUG
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/pagemap.h>
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#include <linux/init.h>
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#include <asm/semaphore.h>
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#include "sysfs.h"
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/* Random magic number */
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#define SYSFS_MAGIC 0x62656572
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struct vfsmount *sysfs_mount;
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struct super_block * sysfs_sb = NULL;
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struct kmem_cache *sysfs_dir_cachep;
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static const struct super_operations sysfs_ops = {
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.statfs = simple_statfs,
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.drop_inode = sysfs_delete_inode,
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};
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struct sysfs_dirent sysfs_root = {
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.s_count = ATOMIC_INIT(1),
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.s_flags = SYSFS_ROOT,
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.s_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
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.s_ino = 1,
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};
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static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *inode;
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struct dentry *root;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = SYSFS_MAGIC;
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sb->s_op = &sysfs_ops;
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sb->s_time_gran = 1;
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sysfs_sb = sb;
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inode = new_inode(sysfs_sb);
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if (!inode) {
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pr_debug("sysfs: could not get root inode\n");
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return -ENOMEM;
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}
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sysfs_init_inode(&sysfs_root, inode);
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inode->i_op = &sysfs_dir_inode_operations;
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inode->i_fop = &sysfs_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inc_nlink(inode);
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root = d_alloc_root(inode);
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if (!root) {
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pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
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iput(inode);
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return -ENOMEM;
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}
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sysfs_root.s_dentry = root;
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root->d_fsdata = &sysfs_root;
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sb->s_root = root;
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return 0;
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}
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static int sysfs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data, struct vfsmount *mnt)
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{
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return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
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}
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static struct file_system_type sysfs_fs_type = {
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.name = "sysfs",
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.get_sb = sysfs_get_sb,
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.kill_sb = kill_litter_super,
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};
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int __init sysfs_init(void)
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{
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int err = -ENOMEM;
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sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
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sizeof(struct sysfs_dirent),
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0, 0, NULL, NULL);
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if (!sysfs_dir_cachep)
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goto out;
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err = register_filesystem(&sysfs_fs_type);
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if (!err) {
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sysfs_mount = kern_mount(&sysfs_fs_type);
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if (IS_ERR(sysfs_mount)) {
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printk(KERN_ERR "sysfs: could not mount!\n");
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err = PTR_ERR(sysfs_mount);
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sysfs_mount = NULL;
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unregister_filesystem(&sysfs_fs_type);
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goto out_err;
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}
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} else
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goto out_err;
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out:
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return err;
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out_err:
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kmem_cache_destroy(sysfs_dir_cachep);
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sysfs_dir_cachep = NULL;
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goto out;
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}
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