git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From eb4a22ba43d91d58a35bc4fce11d8e6065bb4e1d Mon Sep 17 00:00:00 2001
   2 From: Jeff Layton <jlayton@redhat.com>
   3 Date: Wed, 7 Aug 2013 10:29:08 -0400
   4 Subject: cifs: don't instantiate new dentries in readdir for inodes that need to be revalidated immediately
   5
   6 From: Jeff Layton <jlayton@redhat.com>
   7
   8 commit 757c4f6260febff982276818bb946df89c1105aa upstream.
   9
  10 David reported that commit c2b93e06 (cifs: only set ops for inodes in
  11 I_NEW state) caused a regression with mfsymlinks. Prior to that patch,
  12 if a mfsymlink dentry was instantiated at readdir time, the inode would
  13 get a new set of ops when it was revalidated. After that patch, this
  14 did not occur.
  15
  16 This patch addresses this by simply skipping instantiating dentries in
  17 the readdir codepath when we know that they will need to be immediately
  18 revalidated. The next attempt to use that dentry will cause a new lookup
  19 to occur (which is basically what we want to happen anyway).
  20
  21 Cc: "Stefan (metze) Metzmacher" <metze@samba.org>
  22 Cc: Sachin Prabhu <sprabhu@redhat.com>
  23 Reported-and-Tested-by: David McBride <dwm37@cam.ac.uk>
  24 Signed-off-by: Jeff Layton <jlayton@redhat.com>
  25 Signed-off-by: Steve French <smfrench@gmail.com>
  26 [bwh: Backported to 3.2: need to return NULL]
  27 Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
  28 Cc: Rui Xiang <rui.xiang@huawei.com>
  29 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  30
  31 ---
  32  fs/cifs/readdir.c |    8 ++++++++
  33  1 file changed, 8 insertions(+)
  34
  35 --- a/fs/cifs/readdir.c
  36 +++ b/fs/cifs/readdir.c
  37 @@ -96,6 +96,14 @@ cifs_readdir_lookup(struct dentry *paren
  38                 dput(dentry);
  39         }
  40
  41 +       /*
  42 +        * If we know that the inode will need to be revalidated immediately,
  43 +        * then don't create a new dentry for it. We'll end up doing an on
  44 +        * the wire call either way and this spares us an invalidation.
  45 +        */
  46 +       if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
  47 +               return NULL;
  48 +
  49         dentry = d_alloc(parent, name);
  50         if (dentry == NULL)
  51                 return NULL;