CIFS: Force revalidate inode when dentry is stale

BugLink: https://bugs.launchpad.net/bugs/1850541
commit c82e5ac7fe3570a269c0929bf7899f62048e7dbc upstream.

Currently the client indicates that a dentry is stale when inode
numbers or type types between a local inode and a remote file
don't match. If this is the case attributes is not being copied
from remote to local, so, it is already known that the local copy
has stale metadata. That's why the inode needs to be marked for
revalidation in order to tell the VFS to lookup the dentry again
before openning a file. This prevents unexpected stale errors
to be returned to the user space when openning a file.

Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 452b30e46a63c61de0ba51a907613d4e5eae7b31..94e6e7a40a463c7233e2c1731e3df7204f1b1b33 100644 (file)
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -410,6 +410,7 @@ int cifs_get_inode_info_unix(struct inode **pinode,
                /* if uniqueid is different, return error */
                if (unlikely(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM &&
                    CIFS_I(*pinode)->uniqueid != fattr.cf_uniqueid)) {
+                       CIFS_I(*pinode)->time = 0; /* force reval */
                        rc = -ESTALE;
                        goto cgiiu_exit;
                }
@@ -417,6 +418,7 @@ int cifs_get_inode_info_unix(struct inode **pinode,
                /* if filetype is different, return error */
                if (unlikely(((*pinode)->i_mode & S_IFMT) !=
                    (fattr.cf_mode & S_IFMT))) {
+                       CIFS_I(*pinode)->time = 0; /* force reval */
                        rc = -ESTALE;
                        goto cgiiu_exit;
                }
@@ -925,6 +927,7 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
                /* if uniqueid is different, return error */
                if (unlikely(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM &&
                    CIFS_I(*inode)->uniqueid != fattr.cf_uniqueid)) {
+                       CIFS_I(*inode)->time = 0; /* force reval */
                        rc = -ESTALE;
                        goto cgii_exit;
                }
@@ -932,6 +935,7 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
                /* if filetype is different, return error */
                if (unlikely(((*inode)->i_mode & S_IFMT) !=
                    (fattr.cf_mode & S_IFMT))) {
+                       CIFS_I(*inode)->time = 0; /* force reval */
                        rc = -ESTALE;
                        goto cgii_exit;
                }