[PATCH] r/o bind mount prepwork: move open_namei()'s vfs_create()

The code around vfs_create() in open_namei() is getting a bit too complex.
Right now, there is at least the reference count on the dentry, and the
i_mutex to worry about.  Soon, we'll also have mnt_writecount.

So, break the vfs_create() call out of open_namei(), and into a helper
function.  This duplicates the call to may_open(), but that isn't such a bad
thing since the arguments (acc_mode and flag) were being heavily massaged
anyway.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/namei.c b/fs/namei.c
index 7bdceed..28d49b3 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1595,6 +1595,24 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
        return 0;
 }
 
+static int open_namei_create(struct nameidata *nd, struct path *path,
+                               int flag, int mode)
+{
+       int error;
+       struct dentry *dir = nd->dentry;
+
+       if (!IS_POSIXACL(dir->d_inode))
+               mode &= ~current->fs->umask;
+       error = vfs_create(dir->d_inode, path->dentry, mode, nd);
+       mutex_unlock(&dir->d_inode->i_mutex);
+       dput(nd->dentry);
+       nd->dentry = path->dentry;
+       if (error)
+               return error;
+       /* Don't check for write permission, don't truncate */
+       return may_open(nd, 0, flag & ~O_TRUNC);
+}
+
 /*
  *     open_namei()
  *
@@ -1676,18 +1694,10 @@ do_last:
 
        /* Negative dentry, just create the file */
        if (!path.dentry->d_inode) {
-               if (!IS_POSIXACL(dir->d_inode))
-                       mode &= ~current->fs->umask;
-               error = vfs_create(dir->d_inode, path.dentry, mode, nd);
-               mutex_unlock(&dir->d_inode->i_mutex);
-               dput(nd->dentry);
-               nd->dentry = path.dentry;
+               error = open_namei_create(nd, &path, flag, mode);
                if (error)
                        goto exit;
-               /* Don't check for write permission, don't truncate */
-               acc_mode = 0;
-               flag &= ~O_TRUNC;
-               goto ok;
+               return 0;
        }
 
        /*