cluster/afr: Fail open on split-brain

Problem:
Append on a file with split-brain succeeds. Open is intercepted by open-behind,
when write comes on the file, open-behind does open+write. Open succeeds
because afr doesn't fail it. Then write succeeds because write-behind
intercepts it. Flush is also intercepted by write-behind, so the application
never gets to know that the write failed.

Fix:
Fail open on split-brain, so that when open-behind does open+write open fails
which leads to write failure. Application will know about this failure.

Change-Id: I4bff1c747c97bb2925d6987f4ced5f1ce75dbc15
BUG: 1294051
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

11 files changed, 208 insertions, 95 deletions

diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 01357fe2e08..f2a165d2b05 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -253,8 +253,9 @@ __afr_set_in_flight_sb_status (xlator_t *this, afr_local_t *local,
                         local->transaction.in_flight_sb = _gf_true;
                         metadatamap |= (1 << index);
                 }
-                if (metadatamap_old != metadatamap)
+                if (metadatamap_old != metadatamap) {
                         event = 0;
+                }
                 break;
 
         case AFR_DATA_TRANSACTION:
@@ -281,19 +282,71 @@ __afr_set_in_flight_sb_status (xlator_t *this, afr_local_t *local,
         return ret;
 }
 
-int
-afr_set_in_flight_sb_status (xlator_t *this, afr_local_t *local, inode_t *inode)
+gf_boolean_t
+afr_is_symmetric_error (call_frame_t *frame, xlator_t *this)
 {
-        int            ret  = -1;
+        afr_local_t *local = NULL;
         afr_private_t *priv = NULL;
+        int op_errno = 0;
+        int i_errno = 0;
+        gf_boolean_t matching_errors = _gf_true;
+        int i = 0;
+
+        priv = this->private;
+        local = frame->local;
+
+        for (i = 0; i < priv->child_count; i++) {
+                if (!local->replies[i].valid)
+                        continue;
+                if (local->replies[i].op_ret != -1) {
+                        /* Operation succeeded on at least one subvol,
+                           so it is not a failed-everywhere situation.
+                        */
+                        matching_errors = _gf_false;
+                        break;
+                }
+                i_errno = local->replies[i].op_errno;
+
+                if (i_errno == ENOTCONN) {
+                        /* ENOTCONN is not a symmetric error. We do not
+                           know if the operation was performed on the
+                           backend or not.
+                        */
+                        matching_errors = _gf_false;
+                        break;
+                }
+
+                if (!op_errno) {
+                        op_errno = i_errno;
+                } else if (op_errno != i_errno) {
+                        /* Mismatching op_errno's */
+                        matching_errors = _gf_false;
+                        break;
+                }
+        }
+
+        return matching_errors;
+}
+
+int
+afr_set_in_flight_sb_status (xlator_t *this, call_frame_t *frame,
+                             inode_t *inode)
+{
+        int           ret    = -1;
+        afr_private_t *priv  = NULL;
+        afr_local_t   *local = NULL;
 
         priv = this->private;
+        local = frame->local;
 
         /* If this transaction saw no failures, then exit. */
         if (AFR_COUNT (local->transaction.failed_subvols,
                        priv->child_count) == 0)
                 return 0;
 
+        if (afr_is_symmetric_error (frame, this))
+                return 0;
+
         LOCK (&inode->lock);
         {
                 ret = __afr_set_in_flight_sb_status (this, local, inode);
@@ -546,8 +599,9 @@ afr_inode_get_readable (call_frame_t *frame, inode_t *inode, xlator_t *this,
                 }
         } else {
                 /* For files, abort in case of data/metadata split-brain. */
-                if (!data_count || !metadata_count)
+                if (!data_count || !metadata_count) {
                         return -EIO;
+                }
         }
 
         if (type == AFR_METADATA_TRANSACTION && readable)
@@ -1952,6 +2006,11 @@ afr_local_cleanup (afr_local_t *local, xlator_t *this)
                 GF_FREE (local->cont.opendir.checksum);
         }
 
+        { /* open */
+                if (local->cont.open.fd)
+                        fd_unref (local->cont.open.fd);
+        }
+
         { /* readdirp */
                 if (local->cont.readdir.dict)
                         dict_unref (local->cont.readdir.dict);
@@ -2529,9 +2588,11 @@ afr_lookup_metadata_heal_check (call_frame_t *frame, xlator_t *this)
         if (!afr_can_start_metadata_self_heal (frame, this))
                 goto out;
 
-        heal = afr_frame_create (this);
-        if (!heal)
+        heal = afr_frame_create (this, &ret);
+        if (!heal) {
+                ret = -ret;
                 goto out;
+        }
 
         ret = synctask_new (this->ctx->env, afr_lookup_sh_metadata_wrap,
                             afr_refresh_selfheal_done, heal, frame);
@@ -2624,7 +2685,7 @@ afr_lookup_entry_heal (call_frame_t *frame, xlator_t *this)
 	}
 
 	if (need_heal) {
-		heal = afr_frame_create (this);
+		heal = afr_frame_create (this, NULL);
 		if (!heal)
                         goto metadata_heal;
 
diff --git a/xlators/cluster/afr/src/afr-inode-write.c b/xlators/cluster/afr/src/afr-inode-write.c
index 6651e92f482..97397f986b5 100644
--- a/xlators/cluster/afr/src/afr-inode-write.c
+++ b/xlators/cluster/afr/src/afr-inode-write.c
@@ -131,7 +131,7 @@ __afr_inode_write_finalize (call_frame_t *frame, xlator_t *this)
 		}
 	}
 
-        afr_set_in_flight_sb_status (this, local, local->inode);
+        afr_set_in_flight_sb_status (this, frame, local->inode);
 }
 
 
diff --git a/xlators/cluster/afr/src/afr-open.c b/xlators/cluster/afr/src/afr-open.c
index 7a628350c34..6c625ccf7da 100644
--- a/xlators/cluster/afr/src/afr-open.c
+++ b/xlators/cluster/afr/src/afr-open.c
@@ -66,16 +66,15 @@ afr_open_ftruncate_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         return 0;
 }
 
-
 int
 afr_open_cbk (call_frame_t *frame, void *cookie,
               xlator_t *this, int32_t op_ret, int32_t op_errno,
               fd_t *fd, dict_t *xdata)
 {
-        afr_local_t *  local       = NULL;
-        int            call_count  = -1;
-        int            child_index = (long) cookie;
-	afr_fd_ctx_t  *fd_ctx = NULL;
+        afr_local_t   *local           = NULL;
+        int           call_count       = -1;
+        int           child_index      = (long) cookie;
+        afr_fd_ctx_t  *fd_ctx          = NULL;
 
         local = frame->local;
 	fd_ctx = local->fd_ctx;
@@ -103,24 +102,62 @@ afr_open_cbk (call_frame_t *frame, void *cookie,
                                     fd, 0, NULL);
                 } else {
                         AFR_STACK_UNWIND (open, frame, local->op_ret,
-                                          local->op_errno, local->fd,
-					  local->xdata_rsp);
+                                          local->op_errno, local->cont.open.fd,
+                                          local->xdata_rsp);
                 }
         }
 
         return 0;
 }
 
+
+int
+afr_open_continue (call_frame_t *frame, xlator_t *this, int err)
+{
+        afr_local_t   *local     = NULL;
+        afr_private_t *priv      = NULL;
+        int           call_count = 0;
+        int           i          = 0;
+
+        local  = frame->local;
+        priv   = this->private;
+
+        if (err) {
+                AFR_STACK_UNWIND (open, frame, -1, -err, NULL, NULL);
+        } else {
+                local->call_count = AFR_COUNT (local->child_up,
+                                               priv->child_count);
+                call_count = local->call_count;
+
+                for (i = 0; i < priv->child_count; i++) {
+                        if (local->child_up[i]) {
+                                STACK_WIND_COOKIE (frame, afr_open_cbk,
+                                                   (void *)(long)i,
+                                                   priv->children[i],
+                                                  priv->children[i]->fops->open,
+                                                   &local->loc,
+                                            (local->cont.open.flags & ~O_TRUNC),
+                                                   local->cont.open.fd,
+                                                   local->xdata_req);
+                                if (!--call_count)
+                                        break;
+                        }
+                }
+        }
+        return 0;
+}
+
 int
 afr_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
           fd_t *fd, dict_t *xdata)
 {
-        afr_private_t * priv       = NULL;
-        afr_local_t *   local      = NULL;
-        int             i          = 0;
-        int32_t         call_count = 0;
-        int32_t         op_errno   = 0;
-	afr_fd_ctx_t   *fd_ctx = NULL;
+        afr_private_t *priv            = NULL;
+        afr_local_t   *local           = NULL;
+        int           spb_choice       = 0;
+        int           event_generation = 0;
+        int           ret              = 0;
+        int32_t       op_errno         = 0;
+        afr_fd_ctx_t  *fd_ctx          = NULL;
 
         //We can't let truncation to happen outside transaction.
 
@@ -140,23 +177,27 @@ afr_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
         if (!afr_is_consistent_io_possible (local, priv, &op_errno))
 		goto out;
 
-        local->fd = fd_ref (fd);
+        local->inode = inode_ref (loc->inode);
+        loc_copy (&local->loc, loc);
 	local->fd_ctx = fd_ctx;
 	fd_ctx->flags = flags;
-
-        call_count = local->call_count;
+        if (xdata)
+                local->xdata_req = dict_ref (xdata);
 
         local->cont.open.flags = flags;
-
-        for (i = 0; i < priv->child_count; i++) {
-                if (local->child_up[i]) {
-                        STACK_WIND_COOKIE (frame, afr_open_cbk, (void *) (long) i,
-                                           priv->children[i],
-                                           priv->children[i]->fops->open,
-                                           loc, (flags & ~O_TRUNC), fd, xdata);
-                        if (!--call_count)
-                                break;
-                }
+        local->cont.open.fd = fd_ref (fd);
+
+        ret = afr_inode_get_readable (frame, local->inode, this,
+                                      NULL, &event_generation,
+                                      AFR_DATA_TRANSACTION);
+        if ((ret < 0) &&
+            (afr_inode_split_brain_choice_get (local->inode,
+                                             this, &spb_choice) == 0) &&
+            spb_choice < 0) {
+                afr_inode_refresh (frame, this, local->inode,
+                                   local->inode->gfid, afr_open_continue);
+        } else {
+                afr_open_continue (frame, this, 0);
         }
 
 	return 0;
diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index 20e81dd43e0..26d3860b234 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -66,9 +66,9 @@ afr_lookup_and_heal_gfid (xlator_t *this, inode_t *parent, const char *name,
                 goto out;
         }
 
-        frame = afr_frame_create (this);
+        frame = afr_frame_create (this, &ret);
         if (!frame) {
-                ret = -ENOMEM;
+                ret = -ret;
                 goto out;
         }
 
@@ -2349,18 +2349,17 @@ afr_inode_find (xlator_t *this, uuid_t gfid)
 
 
 call_frame_t *
-afr_frame_create (xlator_t *this)
+afr_frame_create (xlator_t *this, int32_t *op_errno)
 {
 	call_frame_t *frame    = NULL;
 	afr_local_t  *local    = NULL;
-	int           op_errno = 0;
 	pid_t         pid      = GF_CLIENT_PID_SELF_HEALD;
 
 	frame = create_frame (this, this->ctx->pool);
 	if (!frame)
 		return NULL;
 
-	local = AFR_FRAME_INIT (frame, op_errno);
+	local = AFR_FRAME_INIT (frame, (*op_errno));
 	if (!local) {
 		STACK_DESTROY (frame->root);
 		return NULL;
@@ -2490,7 +2489,7 @@ afr_selfheal (xlator_t *this, uuid_t gfid)
 	call_frame_t *frame = NULL;
         afr_local_t *local = NULL;
 
-	frame = afr_frame_create (this);
+	frame = afr_frame_create (this, NULL);
 	if (!frame)
 		return ret;
 
diff --git a/xlators/cluster/afr/src/afr-self-heal-data.c b/xlators/cluster/afr/src/afr-self-heal-data.c
index 2c254e80aa1..8cf43f2807b 100644
--- a/xlators/cluster/afr/src/afr-self-heal-data.c
+++ b/xlators/cluster/afr/src/afr-self-heal-data.c
@@ -776,13 +776,37 @@ out:
 	return ret;
 }
 
+int
+afr_selfheal_data_open_cbk (call_frame_t *frame, void *cookie,
+                            xlator_t *this, int32_t op_ret, int32_t op_errno,
+                            fd_t *fd, dict_t *xdata)
+{
+        afr_local_t *local = NULL;
+        int         i      = (long) cookie;
+
+        local = frame->local;
+
+        local->replies[i].valid = 1;
+        local->replies[i].op_ret = op_ret;
+        local->replies[i].op_errno = op_errno;
+
+        syncbarrier_wake (&local->barrier);
+
+        return 0;
+}
 
 int
 afr_selfheal_data_open (xlator_t *this, inode_t *inode, fd_t **fd)
 {
-	int         ret    = 0;
-        fd_t       *fd_tmp = NULL;
-	loc_t       loc    = {0,};
+        int           ret      = 0;
+        fd_t          *fd_tmp  = NULL;
+        loc_t         loc      = {0,};
+        call_frame_t  *frame   = NULL;
+        afr_local_t   *local   = NULL;
+        afr_private_t *priv    = NULL;
+        int           i        = 0;
+
+        priv = this->private;
 
 	fd_tmp = fd_create (inode, 0);
 	if (!fd_tmp)
@@ -791,7 +815,31 @@ afr_selfheal_data_open (xlator_t *this, inode_t *inode, fd_t **fd)
 	loc.inode = inode_ref (inode);
 	gf_uuid_copy (loc.gfid, inode->gfid);
 
-	ret = syncop_open (this, &loc, O_RDWR|O_LARGEFILE, fd_tmp, NULL, NULL);
+        frame = afr_frame_create (this, &ret);
+        if (!frame) {
+                ret = -ret;
+                fd_unref (fd_tmp);
+                goto out;
+        }
+        local = frame->local;
+
+        AFR_ONLIST (local->child_up, frame, afr_selfheal_data_open_cbk, open,
+                    &loc, O_RDWR|O_LARGEFILE, fd_tmp, NULL);
+
+        ret = -ENOTCONN;
+        for (i = 0; i < priv->child_count; i++) {
+                if (!local->replies[i].valid)
+                        continue;
+
+                if (local->replies[i].op_ret < 0) {
+                        ret = -local->replies[i].op_errno;
+                        continue;
+                }
+
+                ret = 0;
+                break;
+        }
+
 	if (ret < 0) {
 		fd_unref (fd_tmp);
                 goto out;
@@ -802,6 +850,8 @@ afr_selfheal_data_open (xlator_t *this, inode_t *inode, fd_t **fd)
         *fd = fd_tmp;
 out:
         loc_wipe (&loc);
+        if (frame)
+                AFR_STACK_DESTROY (frame);
 	return ret;
 }
 
diff --git a/xlators/cluster/afr/src/afr-self-heal-metadata.c b/xlators/cluster/afr/src/afr-self-heal-metadata.c
index f23cf8ec6ee..199f8961480 100644
--- a/xlators/cluster/afr/src/afr-self-heal-metadata.c
+++ b/xlators/cluster/afr/src/afr-self-heal-metadata.c
@@ -486,9 +486,9 @@ afr_selfheal_metadata_by_stbuf (xlator_t *this, struct iatt *stbuf)
                 goto out;
         }
 
-        frame = afr_frame_create (this);
+        frame = afr_frame_create (this, &ret);
         if (!frame) {
-                ret = -ENOMEM;
+                ret = -ret;
                 goto out;
         }
 
diff --git a/xlators/cluster/afr/src/afr-self-heal-name.c b/xlators/cluster/afr/src/afr-self-heal-name.c
index 352d151207e..556d14baf82 100644
--- a/xlators/cluster/afr/src/afr-self-heal-name.c
+++ b/xlators/cluster/afr/src/afr-self-heal-name.c
@@ -670,7 +670,7 @@ afr_selfheal_name (xlator_t *this, uuid_t pargfid, const char *bname,
 	if (!parent)
 		goto out;
 
-	frame = afr_frame_create (this);
+	frame = afr_frame_create (this, NULL);
 	if (!frame)
 		goto out;
 
diff --git a/xlators/cluster/afr/src/afr-self-heal.h b/xlators/cluster/afr/src/afr-self-heal.h
index 8b0047df28f..8e976905e97 100644
--- a/xlators/cluster/afr/src/afr-self-heal.h
+++ b/xlators/cluster/afr/src/afr-self-heal.h
@@ -209,7 +209,7 @@ afr_selfheal_post_op (call_frame_t *frame, xlator_t *this, inode_t *inode,
 		      int subvol, dict_t *xattr, dict_t *xdata);
 
 call_frame_t *
-afr_frame_create (xlator_t *this);
+afr_frame_create (xlator_t *this, int32_t *op_errno);
 
 inode_t *
 afr_inode_find (xlator_t *this, uuid_t gfid);
diff --git a/xlators/cluster/afr/src/afr-self-heald.c b/xlators/cluster/afr/src/afr-self-heald.c
index 74c9bb67931..19cde88a6d5 100644
--- a/xlators/cluster/afr/src/afr-self-heald.c
+++ b/xlators/cluster/afr/src/afr-self-heald.c
@@ -260,7 +260,7 @@ afr_shd_zero_xattrop (xlator_t *this, uuid_t gfid)
         int raw[AFR_NUM_CHANGE_LOGS] = {0};
 
         priv = this->private;
-        frame = afr_frame_create (this);
+        frame = afr_frame_create (this, NULL);
         if (!frame)
                 goto out;
         inode = afr_inode_find (this, gfid);
@@ -457,9 +457,9 @@ afr_shd_index_sweep (struct subvol_healer *healer, char *vgfid)
 	priv = healer->this->private;
 	subvol = priv->children[healer->subvol];
 
-        frame = afr_frame_create (healer->this);
+        frame = afr_frame_create (healer->this, &ret);
         if (!frame) {
-                ret = -ENOMEM;
+                ret = -ret;
                 goto out;
         }
 
diff --git a/xlators/cluster/afr/src/afr-transaction.c b/xlators/cluster/afr/src/afr-transaction.c
index 35621d98493..791c70f6fcc 100644
--- a/xlators/cluster/afr/src/afr-transaction.c
+++ b/xlators/cluster/afr/src/afr-transaction.c
@@ -626,51 +626,10 @@ afr_txn_nothing_failed (call_frame_t *frame, xlator_t *this)
         return _gf_true;
 }
 
-
 void
 afr_handle_symmetric_errors (call_frame_t *frame, xlator_t *this)
 {
-	afr_local_t *local = NULL;
-	afr_private_t *priv = NULL;
-	int op_errno = 0;
-	int i_errno = 0;
-	gf_boolean_t matching_errors = _gf_true;
-	int i = 0;
-
-	priv = this->private;
-	local = frame->local;
-
-	for (i = 0; i < priv->child_count; i++) {
-		if (!local->replies[i].valid)
-			continue;
-		if (local->replies[i].op_ret != -1) {
-			/* Operation succeeded on at least on subvol,
-			   so it is not a failed-everywhere situation.
-			*/
-			matching_errors = _gf_false;
-			break;
-		}
-		i_errno = local->replies[i].op_errno;
-
-		if (i_errno == ENOTCONN) {
-			/* ENOTCONN is not a symmetric error. We do not
-			   know if the operation was performed on the
-			   backend or not.
-			*/
-			matching_errors = _gf_false;
-			break;
-		}
-
-		if (!op_errno) {
-			op_errno = i_errno;
-		} else if (op_errno != i_errno) {
-			/* Mismatching op_errno's */
-			matching_errors = _gf_false;
-			break;
-		}
-	}
-
-	if (matching_errors)
+	if (afr_is_symmetric_error (frame, this))
 		__mark_all_success (frame, this);
 }
 
diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index c4ceb66914f..8cd687398f0 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -519,6 +519,7 @@ typedef struct _afr_local {
 
                 struct {
                         int32_t flags;
+                        fd_t *fd;
                 } open;
 
                 struct {
@@ -1213,7 +1214,7 @@ int
 afr_get_msg_id (char *op_type);
 
 int
-afr_set_in_flight_sb_status (xlator_t *this, afr_local_t *local,
+afr_set_in_flight_sb_status (xlator_t *this, call_frame_t *frame,
                              inode_t *inode);
 
 int32_t
@@ -1262,4 +1263,6 @@ int
 afr_serialize_xattrs_with_delimiter (call_frame_t *frame, xlator_t *this,
                                      char *buf, const char *default_str,
                                      int32_t *serz_len, char delimiter);
+gf_boolean_t
+afr_is_symmetric_error (call_frame_t *frame, xlator_t *this);
 #endif /* __AFR_H__ */