beginning to untangle do_filp_open()
Al Viro [Thu, 24 Dec 2009 06:26:48 +0000 (01:26 -0500)]
That's going to be a long and painful series.  The first step:
take the stuff reachable from 'ok' label in do_filp_open() into
a new helper (finish_open()).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

index 0741c69..60b74b3 100644 (file)
@@ -1590,6 +1590,61 @@ static int open_will_truncate(int flag, struct inode *inode)
        return (flag & O_TRUNC);
 }
 
+static struct file *finish_open(struct nameidata *nd,
+                               int open_flag, int flag, int acc_mode)
+{
+       struct file *filp;
+       int will_truncate;
+       int error;
+
+       will_truncate = open_will_truncate(flag, nd->path.dentry->d_inode);
+       if (will_truncate) {
+               error = mnt_want_write(nd->path.mnt);
+               if (error)
+                       goto exit;
+       }
+       error = may_open(&nd->path, acc_mode, open_flag);
+       if (error) {
+               if (will_truncate)
+                       mnt_drop_write(nd->path.mnt);
+               goto exit;
+       }
+       filp = nameidata_to_filp(nd);
+       if (!IS_ERR(filp)) {
+               error = ima_file_check(filp, acc_mode);
+               if (error) {
+                       fput(filp);
+                       filp = ERR_PTR(error);
+               }
+       }
+       if (!IS_ERR(filp)) {
+               if (acc_mode & MAY_WRITE)
+                       vfs_dq_init(nd->path.dentry->d_inode);
+
+               if (will_truncate) {
+                       error = handle_truncate(&nd->path);
+                       if (error) {
+                               fput(filp);
+                               filp = ERR_PTR(error);
+                       }
+               }
+       }
+       /*
+        * It is now safe to drop the mnt write
+        * because the filp has had a write taken
+        * on its behalf.
+        */
+       if (will_truncate)
+               mnt_drop_write(nd->path.mnt);
+       return filp;
+
+exit:
+       if (!IS_ERR(nd->intent.open.file))
+               release_open_intent(nd);
+       path_put(&nd->path);
+       return ERR_PTR(error);
+}
+
 /*
  * Note that the low bits of the passed in "open_flag"
  * are not the same as in the local variable "flag". See
@@ -1604,7 +1659,6 @@ struct file *do_filp_open(int dfd, const char *pathname,
        struct path path;
        struct dentry *dir;
        int count = 0;
-       int will_truncate;
        int flag = open_to_namei_flags(open_flag);
        int force_reval = 0;
 
@@ -1769,55 +1823,7 @@ do_last:
        if (S_ISDIR(path.dentry->d_inode->i_mode))
                goto exit;
 ok:
-       /*
-        * Consider:
-        * 1. may_open() truncates a file
-        * 2. a rw->ro mount transition occurs
-        * 3. nameidata_to_filp() fails due to
-        *    the ro mount.
-        * That would be inconsistent, and should
-        * be avoided. Taking this mnt write here
-        * ensures that (2) can not occur.
-        */
-       will_truncate = open_will_truncate(flag, nd.path.dentry->d_inode);
-       if (will_truncate) {
-               error = mnt_want_write(nd.path.mnt);
-               if (error)
-                       goto exit;
-       }
-       error = may_open(&nd.path, acc_mode, open_flag);
-       if (error) {
-               if (will_truncate)
-                       mnt_drop_write(nd.path.mnt);
-               goto exit;
-       }
-       filp = nameidata_to_filp(&nd);
-       if (!IS_ERR(filp)) {
-               error = ima_file_check(filp, acc_mode);
-               if (error) {
-                       fput(filp);
-                       filp = ERR_PTR(error);
-               }
-       }
-       if (!IS_ERR(filp)) {
-               if (acc_mode & MAY_WRITE)
-                       vfs_dq_init(nd.path.dentry->d_inode);
-
-               if (will_truncate) {
-                       error = handle_truncate(&nd.path);
-                       if (error) {
-                               fput(filp);
-                               filp = ERR_PTR(error);
-                       }
-               }
-       }
-       /*
-        * It is now safe to drop the mnt write
-        * because the filp has had a write taken
-        * on its behalf.
-        */
-       if (will_truncate)
-               mnt_drop_write(nd.path.mnt);
+       filp = finish_open(&nd, open_flag, flag, acc_mode);
        if (nd.root.mnt)
                path_put(&nd.root);
        return filp;