procfs: fix race between symlink removals and traversals

[pandora-kernel.git] / fs / proc / generic.c

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 7fea132..be65b20 100644 (file)
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -19,7 +19,6 @@
 #include <linux/mount.h>
 #include <linux/init.h>
 #include <linux/idr.h>
-#include <linux/namei.h>
 #include <linux/bitops.h>
 #include <linux/spinlock.h>
 #include <linux/completion.h>
@@ -122,7 +121,7 @@ static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
                        struct kstat *stat)
 {
        struct inode *inode = dentry->d_inode;
-       struct proc_dir_entry *de = PROC_I(inode)->pde;
+       struct proc_dir_entry *de = PDE(inode);
        if (de && de->nlink)
                set_nlink(inode, de->nlink);
 
@@ -223,17 +222,6 @@ void proc_free_inum(unsigned int inum)
        spin_unlock_irqrestore(&proc_inum_lock, flags);
 }
 
-static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-       nd_set_link(nd, __PDE_DATA(dentry->d_inode));
-       return NULL;
-}
-
-static const struct inode_operations proc_link_inode_operations = {
-       .readlink       = generic_readlink,
-       .follow_link    = proc_follow_link,
-};
-
 /*
  * Don't create negative dentries here, return -ENOENT by hand
  * instead.
@@ -350,29 +338,12 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
        if (ret)
                return ret;
 
-       if (S_ISDIR(dp->mode)) {
-               dp->proc_fops = &proc_dir_operations;
-               dp->proc_iops = &proc_dir_inode_operations;
-               dir->nlink++;
-       } else if (S_ISLNK(dp->mode)) {
-               dp->proc_iops = &proc_link_inode_operations;
-       } else if (S_ISREG(dp->mode)) {
-               BUG_ON(dp->proc_fops == NULL);
-               dp->proc_iops = &proc_file_inode_operations;
-       } else {
-               WARN_ON(1);
-               proc_free_inum(dp->low_ino);
-               return -EINVAL;
-       }
-
        spin_lock(&proc_subdir_lock);
        dp->parent = dir;
        if (pde_subdir_insert(dir, dp) == false) {
                WARN(1, "proc_dir_entry '%s/%s' already registered\n",
                     dir->name, dp->name);
                spin_unlock(&proc_subdir_lock);
-               if (S_ISDIR(dp->mode))
-                       dir->nlink--;
                proc_free_inum(dp->low_ino);
                return -EEXIST;
        }
@@ -431,6 +402,7 @@ struct proc_dir_entry *proc_symlink(const char *name,
                ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
                if (ent->data) {
                        strcpy((char*)ent->data,dest);
+                       ent->proc_iops = &proc_link_inode_operations;
                        if (proc_register(parent, ent) < 0) {
                                kfree(ent->data);
                                kfree(ent);
@@ -456,8 +428,12 @@ struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
        ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
        if (ent) {
                ent->data = data;
+               ent->proc_fops = &proc_dir_operations;
+               ent->proc_iops = &proc_dir_inode_operations;
+               parent->nlink++;
                if (proc_register(parent, ent) < 0) {
                        kfree(ent);
+                       parent->nlink--;
                        ent = NULL;
                }
        }
@@ -493,6 +469,8 @@ struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
                return NULL;
        }
 
+       BUG_ON(proc_fops == NULL);
+
        if ((mode & S_IALLUGO) == 0)
                mode |= S_IRUGO;
        pde = __proc_create(&parent, name, mode, 1);
@@ -500,6 +478,7 @@ struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
                goto out;
        pde->proc_fops = proc_fops;
        pde->data = data;
+       pde->proc_iops = &proc_file_inode_operations;
        if (proc_register(parent, pde) < 0)
                goto out_free;
        return pde;