CIFS: Force reval dentry if LOOKUP_REVAL flag is set

commit 0b3d0ef9840f7be202393ca9116b857f6f793715 upstream.

Mark inode for force revalidation if LOOKUP_REVAL flag is set.
This tells the client to actually send a QueryInfo request to
the server to obtain the latest metadata in case a directory
or a file were changed remotely. Only do that if the client
doesn't have a lease for the file to avoid unneeded round
trips to the server.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 07e2465c0d50e542f2f5899ed5ea1985e81e348a..68e53fb8db5981035055a79063a9a7d1f58cab25 100644 (file)
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -817,10 +817,16 @@ lookup_out:
 static int
 cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
 {
+       struct inode *inode;
+
        if (flags & LOOKUP_RCU)
                return -ECHILD;
 
        if (direntry->d_inode) {
+               inode = d_inode(direntry);
+               if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
+                       CIFS_I(inode)->time = 0; /* force reval */
+
                if (cifs_revalidate_dentry(direntry))
                        return 0;
                else {
@@ -831,7 +837,7 @@ cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
                         * attributes will have been updated by
                         * cifs_revalidate_dentry().
                         */
-                       if (IS_AUTOMOUNT(direntry->d_inode) &&
+                       if (IS_AUTOMOUNT(inode) &&
                           !(direntry->d_flags & DCACHE_NEED_AUTOMOUNT)) {
                                spin_lock(&direntry->d_lock);
                                direntry->d_flags |= DCACHE_NEED_AUTOMOUNT;