fs/sysfs/dir.c

   1 /*
   2  * dir.c - Operations for sysfs directories.
   3  */
   4
   5 #undef DEBUG
   6
   7 #include <linux/fs.h>
   8 #include <linux/mount.h>
   9 #include <linux/module.h>
  10 #include <linux/kobject.h>
  11 #include "sysfs.h"
  12
  13 DECLARE_RWSEM(sysfs_rename_sem);
  14
  15 static int init_dir(struct inode * inode)
  16 {
  17         inode->i_op = &simple_dir_inode_operations;
  18         inode->i_fop = &simple_dir_operations;
  19
  20         /* directory inodes start off with i_nlink == 2 (for "." entry) */
  21         inode->i_nlink++;
  22         return 0;
  23 }
  24
  25
  26 static int create_dir(struct kobject * k, struct dentry * p,
  27                       const char * n, struct dentry ** d)
  28 {
  29         int error;
  30
  31         down(&p->d_inode->i_sem);
  32         *d = sysfs_get_dentry(p,n);
  33         if (!IS_ERR(*d)) {
  34                 error = sysfs_create(*d,
  35                                          S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO,
  36                                          init_dir);
  37                 if (!error) {
  38                         (*d)->d_fsdata = k;
  39                         p->d_inode->i_nlink++;
  40                 }
  41                 dput(*d);
  42         } else
  43                 error = PTR_ERR(*d);
  44         up(&p->d_inode->i_sem);
  45         return error;
  46 }
  47
  48
  49 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
  50 {
  51         return create_dir(k,k->dentry,n,d);
  52 }
  53
  54 /**
  55  *      sysfs_create_dir - create a directory for an object.
  56  *      @parent:        parent parent object.
  57  *      @kobj:          object we're creating directory for.
  58  */
  59
  60 int sysfs_create_dir(struct kobject * kobj)
  61 {
  62         struct dentry * dentry = NULL;
  63         struct dentry * parent;
  64         int error = 0;
  65
  66         if (!kobj)
  67                 return -EINVAL;
  68
  69         if (kobj->parent)
  70                 parent = kobj->parent->dentry;
  71         else if (sysfs_mount && sysfs_mount->mnt_sb)
  72                 parent = sysfs_mount->mnt_sb->s_root;
  73         else
  74                 return -EFAULT;
  75
  76         error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
  77         if (!error)
  78                 kobj->dentry = dentry;
  79         return error;
  80 }
  81
  82
  83 static void remove_dir(struct dentry * d)
  84 {
  85         struct dentry * parent = dget(d->d_parent);
  86         down(&parent->d_inode->i_sem);
  87         d_delete(d);
  88         if (d->d_inode)
  89                 simple_rmdir(parent->d_inode,d);
  90
  91         pr_debug(" o %s removing done (%d)\n",d->d_name.name,
  92                  atomic_read(&d->d_count));
  93
  94         up(&parent->d_inode->i_sem);
  95         dput(parent);
  96 }
  97
  98 void sysfs_remove_subdir(struct dentry * d)
  99 {
 100         remove_dir(d);
 101 }
 102
 103
 104 /**
 105  *      sysfs_remove_dir - remove an object's directory.
 106  *      @kobj:  object.
 107  *
 108  *      The only thing special about this is that we remove any files in
 109  *      the directory before we remove the directory, and we've inlined
 110  *      what used to be sysfs_rmdir() below, instead of calling separately.
 111  */
 112
 113 void sysfs_remove_dir(struct kobject * kobj)
 114 {
 115         struct list_head * node;
 116         struct dentry * dentry = dget(kobj->dentry);
 117
 118         if (!dentry)
 119                 return;
 120
 121         pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
 122         down(&dentry->d_inode->i_sem);
 123
 124         spin_lock(&dcache_lock);
 125 restart:
 126         node = dentry->d_subdirs.next;
 127         while (node != &dentry->d_subdirs) {
 128                 struct dentry * d = list_entry(node,struct dentry,d_child);
 129
 130                 node = node->next;
 131                 pr_debug(" o %s (%d): ",d->d_name.name,atomic_read(&d->d_count));
 132                 if (!d_unhashed(d) && (d->d_inode)) {
 133                         d = dget_locked(d);
 134                         pr_debug("removing");
 135
 136                         /**
 137                          * Unlink and unhash.
 138                          */
 139                         __d_drop(d);
 140                         spin_unlock(&dcache_lock);
 141                         /* release the target kobject in case of
 142                          * a symlink
 143                          */
 144                         if (S_ISLNK(d->d_inode->i_mode))
 145                                 kobject_put(d->d_fsdata);
 146
 147                         simple_unlink(dentry->d_inode,d);
 148                         dput(d);
 149                         pr_debug(" done\n");
 150                         spin_lock(&dcache_lock);
 151                         /* re-acquired dcache_lock, need to restart */
 152                         goto restart;
 153                 }
 154         }
 155         spin_unlock(&dcache_lock);
 156         up(&dentry->d_inode->i_sem);
 157
 158         remove_dir(dentry);
 159         /**
 160          * Drop reference from dget() on entrance.
 161          */
 162         dput(dentry);
 163 }
 164
 165 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 166 {
 167         int error = 0;
 168         struct dentry * new_dentry, * parent;
 169
 170         if (!strcmp(kobject_name(kobj), new_name))
 171                 return -EINVAL;
 172
 173         if (!kobj->parent)
 174                 return -EINVAL;
 175
 176         down_write(&sysfs_rename_sem);
 177         parent = kobj->parent->dentry;
 178
 179         down(&parent->d_inode->i_sem);
 180
 181         new_dentry = sysfs_get_dentry(parent, new_name);
 182         if (!IS_ERR(new_dentry)) {
 183                 if (!new_dentry->d_inode) {
 184                         error = kobject_set_name(kobj,new_name);
 185                         if (!error)
 186                                 d_move(kobj->dentry, new_dentry);
 187                 }
 188                 dput(new_dentry);
 189         }
 190         up(&parent->d_inode->i_sem);
 191         up_write(&sysfs_rename_sem);
 192
 193         return error;
 194 }
 195
 196 EXPORT_SYMBOL(sysfs_create_dir);
 197 EXPORT_SYMBOL(sysfs_remove_dir);
 198 EXPORT_SYMBOL(sysfs_rename_dir);
 199