NFS: Don't ignore suid/sgid bit changes after a successful write

[pandora-kernel.git] / fs / nfs / write.c

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index a44a872..cd7c651 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -909,9 +909,14 @@ bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx)
  */
 static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
 {
+       struct nfs_inode *nfsi = NFS_I(inode);
+
        if (nfs_have_delegated_attributes(inode))
                goto out;
-       if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_DATA|NFS_INO_REVAL_PAGECACHE))
+       if (nfsi->cache_validity & (NFS_INO_INVALID_DATA|NFS_INO_REVAL_PAGECACHE))
+               return false;
+       smp_rmb();
+       if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags))
                return false;
 out:
        return PageUptodate(page) != 0;
@@ -1348,6 +1353,30 @@ static const struct rpc_call_ops nfs_write_common_ops = {
        .rpc_release = nfs_writeback_release_common,
 };
 
+/*
+ * Special version of should_remove_suid() that ignores capabilities.
+ */
+static int nfs_should_remove_suid(const struct inode *inode)
+{
+       umode_t mode = inode->i_mode;
+       int kill = 0;
+
+       /* suid always must be killed */
+       if (unlikely(mode & S_ISUID))
+               kill = ATTR_KILL_SUID;
+
+       /*
+        * sgid without any exec bits is just a mandatory locking mark; leave
+        * it alone.  If some exec bits are set, it's a real sgid; kill it.
+        */
+       if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
+               kill |= ATTR_KILL_SGID;
+
+       if (unlikely(kill && S_ISREG(mode)))
+               return kill;
+
+       return 0;
+}
 
 /*
  * This function is called when the WRITE call is complete.
@@ -1396,9 +1425,16 @@ void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
                }
        }
 #endif
-       if (task->tk_status < 0)
+       if (task->tk_status < 0) {
                nfs_set_pgio_error(data->header, task->tk_status, argp->offset);
-       else if (resp->count < argp->count) {
+               return;
+       }
+
+       /* Deal with the suid/sgid bit corner case */
+       if (nfs_should_remove_suid(inode))
+               nfs_mark_for_revalidate(inode);
+
+       if (resp->count < argp->count) {
                static unsigned long    complain;
 
                /* This a short write! */