afs: Prevent callback expiry timer overflow

get_seconds() returns real wall-clock seconds. On 32-bit systems
this value will overflow in year 2038 and beyond. This patch changes
afs_vnode record to use ktime_get_real_seconds() instead, for the
fields cb_expires and cb_expires_at.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>

3 files changed, 7 insertions, 6 deletions

diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 6f917dd1238c..c05452a09398 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -145,7 +145,7 @@ static void xdr_decode_AFSCallBack(const __be32 **_bp, struct afs_vnode *vnode)
         vnode->cb_version       = ntohl(*bp++);
         vnode->cb_expiry        = ntohl(*bp++);
         vnode->cb_type          = ntohl(*bp++);
-        vnode->cb_expires       = vnode->cb_expiry + get_seconds();
+        vnode->cb_expires       = vnode->cb_expiry + ktime_get_real_seconds();
         *_bp = bp;
 }
 
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index e083e086b7ca..4079c832ff27 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -246,12 +246,13 @@ struct inode *afs_iget(struct super_block *sb, struct key *key,
                         vnode->cb_version = 0;
                         vnode->cb_expiry = 0;
                         vnode->cb_type = 0;
-                        vnode->cb_expires = get_seconds();
+                        vnode->cb_expires = ktime_get_real_seconds();
                 } else {
                         vnode->cb_version = cb->version;
                         vnode->cb_expiry = cb->expiry;
                         vnode->cb_type = cb->type;
-                        vnode->cb_expires = vnode->cb_expiry + get_seconds();
+                        vnode->cb_expires = vnode->cb_expiry +
+                                ktime_get_real_seconds();
                 }
         }
 
@@ -324,7 +325,7 @@ int afs_validate(struct afs_vnode *vnode, struct key *key)
             !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
             !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
             !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
-                if (vnode->cb_expires < get_seconds() + 10) {
+                if (vnode->cb_expires < ktime_get_real_seconds() + 10) {
                         _debug("callback expired");
                         set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
                 } else {
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 97a16ce200be..832555003d03 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -377,8 +377,8 @@ struct afs_vnode {
         struct rb_node          server_rb;      /* link in server->fs_vnodes */
         struct rb_node          cb_promise;     /* link in server->cb_promises */
         struct work_struct      cb_broken_work; /* work to be done on callback break */
-        time_t                  cb_expires;     /* time at which callback expires */
-        time_t                  cb_expires_at;  /* time used to order cb_promise */
+        time64_t                cb_expires;     /* time at which callback expires */
+        time64_t                cb_expires_at;  /* time used to order cb_promise */
         unsigned                cb_version;     /* callback version */
         unsigned                cb_expiry;      /* callback expiry time */
         afs_callback_type_t     cb_type;        /* type of callback */