glusterfs/SOURCES/0378-Revert-open-behind-fix-missing-fd-reference.patch

From d79660ccc65f163e0d9cf91cc13a199bec04d5f1 Mon Sep 17 00:00:00 2001
From: Xavi Hernandez Juan <xhernandez@redhat.com>
Date: Wed, 20 May 2020 12:55:43 +0000
Subject: [PATCH 378/379] Revert "open-behind: fix missing fd reference"

This reverts commit 30cbdf8c06145a0c290da42ecc0a7eae928200b7.

The patch is not complete because there have been some crash reports
upstream recently after the patch was released. A new patch that should
cover all corner cases is under review (), but it's a big change and it
could be risky to backport it without enough testing.

Since there exists a workaround to avoid the problem (disable
open-behind), for now we revert the patch.

Change-Id: I9cfc55623c33758cf5530b18f03c0d795b0f650b
BUG: 1830713
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>
Reviewed-on: https://code.engineering.redhat.com/gerrit/200952
Tested-by: RHGS Build Bot <nigelb@redhat.com>
Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <sheggodu@redhat.com>
---
 xlators/performance/open-behind/src/open-behind.c | 27 +++++++++--------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/xlators/performance/open-behind/src/open-behind.c b/xlators/performance/open-behind/src/open-behind.c
index 14ebc12..268c717 100644
--- a/xlators/performance/open-behind/src/open-behind.c
+++ b/xlators/performance/open-behind/src/open-behind.c
@@ -206,13 +206,8 @@ ob_fd_free(ob_fd_t *ob_fd)
     if (ob_fd->xdata)
         dict_unref(ob_fd->xdata);
 
-    if (ob_fd->open_frame) {
-        /* If we sill have a frame it means that background open has never
-         * been triggered. We need to release the pending reference. */
-        fd_unref(ob_fd->fd);
-
+    if (ob_fd->open_frame)
         STACK_DESTROY(ob_fd->open_frame->root);
-    }
 
     GF_FREE(ob_fd);
 }
@@ -302,7 +297,6 @@ ob_wake_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int op_ret,
             call_resume(stub);
     }
 
-    /* The background open is completed. We can release the 'fd' reference. */
     fd_unref(fd);
 
     STACK_DESTROY(frame->root);
@@ -337,9 +331,7 @@ ob_fd_wake(xlator_t *this, fd_t *fd, ob_fd_t *ob_fd)
     }
 
     if (frame) {
-        /* We don't need to take a reference here. We already have a reference
-         * while the open is pending. */
-        frame->local = fd;
+        frame->local = fd_ref(fd);
 
         STACK_WIND(frame, ob_wake_cbk, FIRST_CHILD(this),
                    FIRST_CHILD(this)->fops->open, &ob_fd->loc, ob_fd->flags, fd,
@@ -353,12 +345,15 @@ void
 ob_inode_wake(xlator_t *this, struct list_head *ob_fds)
 {
     ob_fd_t *ob_fd = NULL, *tmp = NULL;
+    fd_t *fd = NULL;
 
     if (!list_empty(ob_fds)) {
         list_for_each_entry_safe(ob_fd, tmp, ob_fds, ob_fds_on_inode)
         {
             ob_fd_wake(this, ob_fd->fd, ob_fd);
+            fd = ob_fd->fd;
             ob_fd_free(ob_fd);
+            fd_unref(fd);
         }
     }
 }
@@ -370,7 +365,7 @@ ob_fd_copy(ob_fd_t *src, ob_fd_t *dst)
     if (!src || !dst)
         goto out;
 
-    dst->fd = src->fd;
+    dst->fd = __fd_ref(src->fd);
     dst->loc.inode = inode_ref(src->loc.inode);
     gf_uuid_copy(dst->loc.gfid, src->loc.gfid);
     dst->flags = src->flags;
@@ -514,6 +509,7 @@ ob_open_behind(call_frame_t *frame, xlator_t *this, loc_t *loc, int flags,
 
     ob_fd->ob_inode = ob_inode;
 
+    /* don't do fd_ref, it'll cause leaks */
     ob_fd->fd = fd;
 
     ob_fd->open_frame = copy_frame(frame);
@@ -543,16 +539,15 @@ ob_open_behind(call_frame_t *frame, xlator_t *this, loc_t *loc, int flags,
     }
     UNLOCK(&fd->inode->lock);
 
-    /* We take a reference while the background open is pending or being
-     * processed. If we finally wind the request in the foreground, then
-     * ob_fd_free() will take care of this additional reference. */
-    fd_ref(fd);
-
     if (!open_in_progress && !unlinked) {
+        fd_ref(fd);
+
         STACK_UNWIND_STRICT(open, frame, 0, 0, fd, xdata);
 
         if (!conf->lazy_open)
             ob_fd_wake(this, fd, NULL);
+
+        fd_unref(fd);
     } else {
         ob_fd_free(ob_fd);
         STACK_WIND(frame, default_open_cbk, FIRST_CHILD(this),
-- 
1.8.3.1