cluster/dht: Fix fd check race

There is a another race between the cached subvol
being updated in the inode_ctx and the fd being opened on
the target.

1. fop1 -> fd1 -> subvol0
2. file migrated from subvol0 to subvol1 and cached_subvol
   changed to subvol1 in inode_ctx
3. fop2 -> fd1 -> subvol1 [takes new cached subvol]
4. fop2 -> checks fd ctx (fd not open on subvol1) -> opens fd1 on subvol1
5. fop1 -> checks fd ctx (fd not open on subvol0)
   -> tries to open fd1 on subvol0 -> fails with "No such file on directory".

Fix:
If dht_fd_open_on_dst fails with ENOENT or ESTALE, wind to old subvol
and let the phase1/phase2 checks handle it.

Change-Id: I34f8011574a8b72e3bcfe03b0cc4f024b352f225
BUG: 1467010
> BUG: 1465075
> Signed-off-by: N Balachandran <nbalacha@redhat.com>
> Reviewed-on: https://review.gluster.org/17731
> Smoke: Gluster Build System <jenkins@build.gluster.org>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
> Reviewed-by: Amar Tumballi <amarts@redhat.com>
(cherry picked from commit f7a450c17fee7e43c544473366220887f0534ed7)
Signed-off-by: N Balachandran <nbalacha@redhat.com>
Reviewed-on: https://review.gluster.org/17829
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra Talur <rtalur@redhat.com>

2 files changed, 76 insertions, 1 deletions

diff --git a/xlators/cluster/dht/src/dht-helper.c b/xlators/cluster/dht/src/dht-helper.c
index 3c392fe04be..c9bf60eb591 100644
--- a/xlators/cluster/dht/src/dht-helper.c
+++ b/xlators/cluster/dht/src/dht-helper.c
@@ -293,10 +293,12 @@ dht_check_and_open_fd_on_subvol_complete (int ret, call_frame_t *frame,
         glusterfs_fop_t     fop     = 0;
         dht_local_t        *local   = NULL;
         xlator_t           *subvol  = NULL;
+        xlator_t           *this  = NULL;
         fd_t               *fd      = NULL;
         int                 op_errno = -1;
 
         local = frame->local;
+        this = frame->this;
         fop = local->fop;
         subvol = local->cached_subvol;
         fd = local->fd;
@@ -385,6 +387,11 @@ dht_check_and_open_fd_on_subvol_complete (int ret, call_frame_t *frame,
                 break;
 
         default:
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        DHT_MSG_UNKNOWN_FOP,
+                        "Unknown FOP on fd (%p) on file %s @ %s",
+                        fd, uuid_utoa (fd->inode->gfid),
+                        subvol->name);
                 break;
 
         }
@@ -445,6 +452,11 @@ handle_err:
                 break;
 
         default:
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        DHT_MSG_UNKNOWN_FOP,
+                        "Unknown FOP on fd (%p) on file %s @ %s",
+                        fd, uuid_utoa (fd->inode->gfid),
+                        subvol->name);
                 break;
         }
 
@@ -508,6 +520,20 @@ dht_check_and_open_fd_on_subvol_task (void *data)
                         " (%p, flags=0%o) on file %s @ %s",
                         fd, fd->flags, uuid_utoa (fd->inode->gfid),
                         subvol->name);
+                /* This can happen if the cached subvol was updated in the
+                 * inode_ctx and the fd was opened on the new cached suvol
+                 * after this fop was wound on the old cached subvol.
+                 * As we do not close the fd on the old subvol (a leak)
+                 * don't treat ENOENT as an error and allow the phase1/phase2
+                 * checks to handle it.
+                 */
+
+                if ((-ret != ENOENT) && (-ret != ESTALE)) {
+                        local->op_errno = -ret;
+                        ret = -1;
+                } else {
+                        ret = 0;
+                }
 
                 local->op_errno = -ret;
                 ret = -1;
diff --git a/xlators/cluster/dht/src/dht-messages.h b/xlators/cluster/dht/src/dht-messages.h
index 30b64eb5711..b6184ebe088 100644
--- a/xlators/cluster/dht/src/dht-messages.h
+++ b/xlators/cluster/dht/src/dht-messages.h
@@ -40,7 +40,7 @@
  */
 
 #define GLFS_DHT_BASE                   GLFS_MSGID_COMP_DHT
-#define GLFS_DHT_NUM_MESSAGES           118
+#define GLFS_DHT_NUM_MESSAGES           125
 #define GLFS_MSGID_END          (GLFS_DHT_BASE + GLFS_DHT_NUM_MESSAGES + 1)
 
 /* Messages with message IDs */
@@ -1085,5 +1085,54 @@
  */
 #define DHT_MSG_DIR_LOOKUP_FAILED          (GLFS_DHT_BASE + 118)
 
+/*
+ * @messageid 109119
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_INODELK_FAILED          (GLFS_DHT_BASE + 119)
+
+/*
+ * @messageid 109120
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_LOCK_FRAME_FAILED          (GLFS_DHT_BASE + 120)
+
+/*
+ * @messageid 109121
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_LOCAL_LOCK_INIT_FAILED          (GLFS_DHT_BASE + 121)
+
+/*
+ * @messageid 109122
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_ENTRYLK_ERROR          (GLFS_DHT_BASE + 122)
+
+/*
+ * @messageid 109123
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_INODELK_ERROR          (GLFS_DHT_BASE + 123)
+
+/*
+ * @messageid 109124
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_LOC_FAILED             (GLFS_DHT_BASE + 124)
+
+/*
+ * @messageid 109125
+ * @diagnosis
+ * @recommendedaction None
+ */
+#define DHT_MSG_UNKNOWN_FOP            (GLFS_DHT_BASE + 125)
+
 #define glfs_msg_end_x GLFS_MSGID_END, "Invalid: End of messages"
 #endif /* _DHT_MESSAGES_H_ */