1 files changed, 72 insertions, 2 deletions

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 2f9f3790679d..3b0c62e622da 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -466,8 +466,22 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
                                 cifs_dbg(FYI, "file id match, oplock break\n");
                                 pCifsInode = CIFS_I(netfile->dentry->d_inode);
 
-                                cifs_set_oplock_level(pCifsInode,
-                                        pSMB->OplockLevel ? OPLOCK_READ : 0);
+                                set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
+                                        &pCifsInode->flags);
+
+                                /*
+                                 * Set flag if the server downgrades the oplock
+                                 * to L2 else clear.
+                                 */
+                                if (pSMB->OplockLevel)
+                                        set_bit(
+                                           CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
+                                           &pCifsInode->flags);
+                                else
+                                        clear_bit(
+                                           CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
+                                           &pCifsInode->flags);
+
                                 queue_work(cifsiod_wq,
                                            &netfile->oplock_break);
                                 netfile->oplock_break_cancelled = false;
@@ -551,6 +565,62 @@ void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
                 cinode->oplock = 0;
 }
 
+static int
+cifs_oplock_break_wait(void *unused)
+{
+        schedule();
+        return signal_pending(current) ? -ERESTARTSYS : 0;
+}
+
+/*
+ * We wait for oplock breaks to be processed before we attempt to perform
+ * writes.
+ */
+int cifs_get_writer(struct cifsInodeInfo *cinode)
+{
+        int rc;
+
+start:
+        rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
+                                   cifs_oplock_break_wait, TASK_KILLABLE);
+        if (rc)
+                return rc;
+
+        spin_lock(&cinode->writers_lock);
+        if (!cinode->writers)
+                set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+        cinode->writers++;
+        /* Check to see if we have started servicing an oplock break */
+        if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
+                cinode->writers--;
+                if (cinode->writers == 0) {
+                        clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+                        wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
+                }
+                spin_unlock(&cinode->writers_lock);
+                goto start;
+        }
+        spin_unlock(&cinode->writers_lock);
+        return 0;
+}
+
+void cifs_put_writer(struct cifsInodeInfo *cinode)
+{
+        spin_lock(&cinode->writers_lock);
+        cinode->writers--;
+        if (cinode->writers == 0) {
+                clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+                wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
+        }
+        spin_unlock(&cinode->writers_lock);
+}
+
+void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
+{
+        clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
+        wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
+}
+
 bool
 backup_cred(struct cifs_sb_info *cifs_sb)
 {