Merge remote-tracking branch 'userns/for-next'

[karo-tx-linux.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 29fc6a657477cf49eaa4a722f2b2da39f6c387a6..2b729d253715ba183e912fae98cfec1e68665e24 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1555,8 +1555,6 @@ static int lookup_fast(struct nameidata *nd,
                negative = d_is_negative(dentry);
                if (read_seqcount_retry(&dentry->d_seq, seq))
                        return -ECHILD;
                negative = d_is_negative(dentry);
                if (read_seqcount_retry(&dentry->d_seq, seq))
                        return -ECHILD;

-               if (negative)
-                       return -ENOENT;

 
                /*
                 * This sequence count validates that the parent had no
 
                /*
                 * This sequence count validates that the parent had no


@@ -1577,6 +1575,12 @@ static int lookup_fast(struct nameidata *nd,
                                goto unlazy;
                        }
                }
                                goto unlazy;
                        }
                }

+               /*
+                * Note: do negative dentry check after revalidation in
+                * case that drops it.
+                */
+               if (negative)
+                       return -ENOENT;

                path->mnt = mnt;
                path->dentry = dentry;
                if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
                path->mnt = mnt;
                path->dentry = dentry;
                if (likely(__follow_mount_rcu(nd, path, inode, seqp)))


@@ -1962,7 +1966,7 @@ OK:
                if (err) {
                        const char *s = get_link(nd);
 
                if (err) {
                        const char *s = get_link(nd);
 

-                       if (unlikely(IS_ERR(s)))
+                       if (IS_ERR(s))

                                return PTR_ERR(s);
                        err = 0;
                        if (unlikely(!s)) {
                                return PTR_ERR(s);
                        err = 0;
                        if (unlikely(!s)) {


@@ -2275,6 +2279,8 @@ EXPORT_SYMBOL(vfs_path_lookup);
  *
  * Note that this routine is purely a helper for filesystem usage and should
  * not be called by generic code.
  *
  * Note that this routine is purely a helper for filesystem usage and should
  * not be called by generic code.

+ *
+ * The caller must hold base->i_mutex.

  */
 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 {
  */
 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 {


@@ -2318,6 +2324,78 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 }
 EXPORT_SYMBOL(lookup_one_len);
 
 }
 EXPORT_SYMBOL(lookup_one_len);
 

+/**
+ * lookup_one_len_unlocked - filesystem helper to lookup single pathname component
+ * @name:      pathname component to lookup
+ * @base:      base directory to lookup from
+ * @len:       maximum length @len should be interpreted to
+ *
+ * Note that this routine is purely a helper for filesystem usage and should
+ * not be called by generic code.
+ *
+ * Unlike lookup_one_len, it should be called without the parent
+ * i_mutex held, and will take the i_mutex itself if necessary.
+ */
+struct dentry *lookup_one_len_unlocked(const char *name,
+                                      struct dentry *base, int len)
+{
+       struct qstr this;
+       unsigned int c;
+       int err;
+       struct dentry *ret;
+
+       this.name = name;
+       this.len = len;
+       this.hash = full_name_hash(name, len);
+       if (!len)
+               return ERR_PTR(-EACCES);
+
+       if (unlikely(name[0] == '.')) {
+               if (len < 2 || (len == 2 && name[1] == '.'))
+                       return ERR_PTR(-EACCES);
+       }
+
+       while (len--) {
+               c = *(const unsigned char *)name++;
+               if (c == '/' || c == '\0')
+                       return ERR_PTR(-EACCES);
+       }
+       /*
+        * See if the low-level filesystem might want
+        * to use its own hash..
+        */
+       if (base->d_flags & DCACHE_OP_HASH) {
+               int err = base->d_op->d_hash(base, &this);
+               if (err < 0)
+                       return ERR_PTR(err);
+       }
+
+       err = inode_permission(base->d_inode, MAY_EXEC);
+       if (err)
+               return ERR_PTR(err);
+
+       ret = __d_lookup(base, &this);
+       if (ret)
+               return ret;
+       /*
+        * __d_lookup() is used to try to get a quick answer and avoid the
+        * mutex.  A false-negative does no harm.
+        */
+       ret = __d_lookup(base, &this);
+       if (ret && ret->d_flags & DCACHE_OP_REVALIDATE) {
+               dput(ret);
+               ret = NULL;
+       }
+       if (ret)
+               return ret;
+
+       mutex_lock(&base->d_inode->i_mutex);
+       ret =  __lookup_hash(&this, base, 0);
+       mutex_unlock(&base->d_inode->i_mutex);
+       return ret;
+}
+EXPORT_SYMBOL(lookup_one_len_unlocked);
+

 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
                 struct path *path, int *empty)
 {
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
                 struct path *path, int *empty)
 {


@@ -3376,7 +3454,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
                return ERR_PTR(-ELOOP);
 
        filename = getname_kernel(name);
                return ERR_PTR(-ELOOP);
 
        filename = getname_kernel(name);

-       if (unlikely(IS_ERR(filename)))
+       if (IS_ERR(filename))

                return ERR_CAST(filename);
 
        set_nameidata(&nd, -1, filename);
                return ERR_CAST(filename);
 
        set_nameidata(&nd, -1, filename);