vfs: atomic f_pos accesses as per POSIX

[~andy/linux] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 3531deebad3084104e6a9fca7116ba68890ad5af..2f730ef9b4b3da78afd6a830c13c7ba13c706ffe 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -196,6 +196,7 @@ recopy:
                goto error;
 
        result->uptr = filename;
+       result->aname = NULL;
        audit_getname(result);
        return result;
 
@@ -209,7 +210,35 @@ getname(const char __user * filename)
 {
        return getname_flags(filename, 0, NULL);
 }
-EXPORT_SYMBOL(getname);
+
+/*
+ * The "getname_kernel()" interface doesn't do pathnames longer
+ * than EMBEDDED_NAME_MAX. Deal with it - you're a kernel user.
+ */
+struct filename *
+getname_kernel(const char * filename)
+{
+       struct filename *result;
+       char *kname;
+       int len;
+
+       len = strlen(filename);
+       if (len >= EMBEDDED_NAME_MAX)
+               return ERR_PTR(-ENAMETOOLONG);
+
+       result = __getname();
+       if (unlikely(!result))
+               return ERR_PTR(-ENOMEM);
+
+       kname = (char *)result + sizeof(*result);
+       result->name = kname;
+       result->uptr = NULL;
+       result->aname = NULL;
+       result->separate = false;
+
+       strlcpy(kname, filename, EMBEDDED_NAME_MAX);
+       return result;
+}
 
 #ifdef CONFIG_AUDITSYSCALL
 void putname(struct filename *name)
@@ -235,27 +264,9 @@ static int check_acl(struct inode *inode, int mask)
                return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
        }
 
-       acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
-
-       /*
-        * A filesystem can force a ACL callback by just never filling the
-        * ACL cache. But normally you'd fill the cache either at inode
-        * instantiation time, or on the first ->get_acl call.
-        *
-        * If the filesystem doesn't have a get_acl() function at all, we'll
-        * just create the negative cache entry.
-        */
-       if (acl == ACL_NOT_CACHED) {
-               if (inode->i_op->get_acl) {
-                       acl = inode->i_op->get_acl(inode, ACL_TYPE_ACCESS);
-                       if (IS_ERR(acl))
-                               return PTR_ERR(acl);
-               } else {
-                       set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
-                       return -EAGAIN;
-               }
-       }
-
+       acl = get_acl(inode, ACL_TYPE_ACCESS);
+       if (IS_ERR(acl))
+               return PTR_ERR(acl);
        if (acl) {
                int error = posix_acl_permission(inode, acl, mask);
                posix_acl_release(acl);
@@ -1873,7 +1884,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 
                nd->path = f.file->f_path;
                if (flags & LOOKUP_RCU) {
-                       if (f.need_put)
+                       if (f.flags & FDPUT_FPUT)
                                *fp = f.file;
                        nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
                        rcu_read_lock();
@@ -3945,10 +3956,13 @@ out_dput:
        done_path_create(&new_path, new_dentry);
        if (delegated_inode) {
                error = break_deleg_wait(&delegated_inode);
-               if (!error)
+               if (!error) {
+                       path_put(&old_path);
                        goto retry;
+               }
        }
        if (retry_estale(error, how)) {
+               path_put(&old_path);
                how |= LOOKUP_REVAL;
                goto retry;
        }