[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>

1 files changed, 20 insertions, 10 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 7bdceedd254c..28d49b301d55 100644
--- 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;
         }
 
         /*