smbfs: use dget_parent

Use dget_parent instead of opencoding it.  This simplifies the code, but
more importanly prepares for the more complicated locking for a parent
dget in the dcache scale patch series.

Note that the d_time assignment in smb_renew_times moves out of d_lock,
but it's a single atomic 32-bit value, and that's what other sites
setting it do already.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 7 deletions

diff --git a/fs/smbfs/proc.c b/fs/smbfs/proc.c
index 71c29b6670b4..3dcf638d4d3a 100644
--- a/fs/smbfs/proc.c
+++ b/fs/smbfs/proc.c
@@ -332,16 +332,15 @@ static int smb_build_path(struct smb_sb_info *server, unsigned char *buf,
          * and store it in reversed order [see reverse_string()]
          */
         dget(entry);
-        spin_lock(&entry->d_lock);
         while (!IS_ROOT(entry)) {
                 struct dentry *parent;
 
                 if (maxlen < (3<<unicode)) {
-                        spin_unlock(&entry->d_lock);
                         dput(entry);
                         return -ENAMETOOLONG;
                 }
 
+                spin_lock(&entry->d_lock);
                 len = server->ops->convert(path, maxlen-2, 
                                       entry->d_name.name, entry->d_name.len,
                                       server->local_nls, server->remote_nls);
@@ -359,15 +358,12 @@ static int smb_build_path(struct smb_sb_info *server, unsigned char *buf,
                 }
                 *path++ = '\\';
                 maxlen -= len+1;
-
-                parent = entry->d_parent;
-                dget(parent);
                 spin_unlock(&entry->d_lock);
+
+                parent = dget_parent(entry);
                 dput(entry);
                 entry = parent;
-                spin_lock(&entry->d_lock);
         }
-        spin_unlock(&entry->d_lock);
         dput(entry);
         reverse_string(buf, path-buf);