ocfs2: fix deadlock on mmapped page in ocfs2_write_begin_nolock()

[deliverable/linux.git] / fs / ocfs2 / aops.c

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 98d36548153dc3696619b2923e2eecce35bd6bbc..bbb4b3e5b4ffc5bbf52fc5d4206f52995a988ea1 100644 (file)
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1842,6 +1842,16 @@ out_commit:
        ocfs2_commit_trans(osb, handle);
 
 out:
+       /*
+        * The mmapped page won't be unlocked in ocfs2_free_write_ctxt(),
+        * even in case of error here like ENOSPC and ENOMEM. So, we need
+        * to unlock the target page manually to prevent deadlocks when
+        * retrying again on ENOSPC, or when returning non-VM_FAULT_LOCKED
+        * to VM code.
+        */
+       if (wc->w_target_locked)
+               unlock_page(mmap_page);
+
        ocfs2_free_write_ctxt(inode, wc);
 
        if (data_ac) {