1 files changed, 41 insertions, 0 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c6aad775dd6d..76919c25acc7 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -618,6 +618,37 @@ static loff_t cifs_llseek(struct file *file, loff_t offset, int origin)
         return generic_file_llseek_unlocked(file, offset, origin);
 }
 
+#ifdef CONFIG_CIFS_EXPERIMENTAL
+static int cifs_setlease(struct file *file, long arg, struct file_lock **lease)
+{
+        /* note that this is called by vfs setlease with the BKL held
+           although I doubt that BKL is needed here in cifs */
+        struct inode *inode = file->f_path.dentry->d_inode;
+
+        if (!(S_ISREG(inode->i_mode)))
+                return -EINVAL;
+
+        /* check if file is oplocked */
+        if (((arg == F_RDLCK) &&
+                (CIFS_I(inode)->clientCanCacheRead)) ||
+            ((arg == F_WRLCK) &&
+                (CIFS_I(inode)->clientCanCacheAll)))
+                return generic_setlease(file, arg, lease);
+        else if (CIFS_SB(inode->i_sb)->tcon->local_lease &&
+                        !CIFS_I(inode)->clientCanCacheRead)
+                /* If the server claims to support oplock on this
+                   file, then we still need to check oplock even
+                   if the local_lease mount option is set, but there
+                   are servers which do not support oplock for which
+                   this mount option may be useful if the user
+                   knows that the file won't be changed on the server
+                   by anyone else */
+                return generic_setlease(file, arg, lease);
+        else
+                return -EAGAIN;
+}
+#endif
+
 struct file_system_type cifs_fs_type = {
         .owner = THIS_MODULE,
         .name = "cifs",
@@ -696,6 +727,7 @@ const struct file_operations cifs_file_ops = {
 
 #ifdef CONFIG_CIFS_EXPERIMENTAL
         .dir_notify = cifs_dir_notify,
+        .setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };
 
@@ -716,6 +748,7 @@ const struct file_operations cifs_file_direct_ops = {
         .llseek = cifs_llseek,
 #ifdef CONFIG_CIFS_EXPERIMENTAL
         .dir_notify = cifs_dir_notify,
+        .setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };
 const struct file_operations cifs_file_nobrl_ops = {
@@ -736,6 +769,7 @@ const struct file_operations cifs_file_nobrl_ops = {
 
 #ifdef CONFIG_CIFS_EXPERIMENTAL
         .dir_notify = cifs_dir_notify,
+        .setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };
 
@@ -755,6 +789,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = {
         .llseek = cifs_llseek,
 #ifdef CONFIG_CIFS_EXPERIMENTAL
         .dir_notify = cifs_dir_notify,
+        .setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };
 
@@ -946,6 +981,12 @@ static int cifs_oplock_thread(void *dummyarg)
                                 the call */
                         /* mutex_lock(&inode->i_mutex);*/
                         if (S_ISREG(inode->i_mode)) {
+#ifdef CONFIG_CIFS_EXPERIMENTAL
+                                if (CIFS_I(inode)->clientCanCacheAll == 0)
+                                        break_lease(inode, FMODE_READ);
+                                else if (CIFS_I(inode)->clientCanCacheRead == 0)
+                                        break_lease(inode, FMODE_WRITE);
+#endif
                                 rc = filemap_fdatawrite(inode->i_mapping);
                                 if (CIFS_I(inode)->clientCanCacheRead == 0) {
                                         waitrc = filemap_fdatawait(