VFS: fix recent breakage of FS_REVAL_DOT

commit 176306f59ac7a35369cbba87aff13e14c5916074 upstream.

Commit 1f36f774b22a0ceb7dd33eca626746c81a97b6a5 broke FS_REVAL_DOT semantics.

In particular, before this patch, the command
   ls -l
in an NFS mounted directory would always check if the directory on the server
had changed and if so would flush and refill the pagecache for the dir.
After this patch, the same "ls -l" will repeatedly return stale date until
the cached attributes for the directory time out.

The following patch fixes this by ensuring the d_revalidate is called by
do_last when "." is being looked-up.
link_path_walk has already called d_revalidate, but in that case LOOKUP_OPEN
is not set so nfs_lookup_verify_inode chooses not to do any validation.

The following patch restores the original behaviour.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/namei.c b/fs/namei.c
index b86b96fe1dc33926eb242a2a2e21061fe46145a5..f6c7fcfa818114dc7b12137519dad5c24742c240 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1620,6 +1620,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
        case LAST_DOTDOT:
                follow_dotdot(nd);
                dir = nd->path.dentry;
+       case LAST_DOT:
                if (nd->path.mnt->mnt_sb->s_type->fs_flags & FS_REVAL_DOT) {
                        if (!dir->d_op->d_revalidate(dir, nd)) {
                                error = -ESTALE;
@@ -1627,7 +1628,6 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
                        }
                }
                /* fallthrough */
-       case LAST_DOT:
        case LAST_ROOT:
                if (open_flag & O_CREAT)
                        goto exit;