cluster/afr: Do self-heal on reopened fds.

This patch brings in partial support for self-heal of open
fds. The precondition is that the fd should have been opened
successfully during the initial open() (or create()), and we
assume that protocol/client has successfully reopened the fd
when the subvolume comes back up.

It works by doing an "up/down flush" (a dummy flush transaction
to do post-op wherever necessary) and then triggering
data self-heal on the file in the post-post-op hook of the
dummy flush transaction. This ensures that any writes
that come in during self-heal will wait until self-heal completes.

The up/down flush is also done when a subvolume goes down,
so that post-op is done on all subvolumes where pre-op was done.

Signed-off-by: Vikas Gorur <vikas@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 170 (Auto-heal fails on files that are open()-ed/mmap()-ed)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=170

1 files changed, 356 insertions, 0 deletions

diff --git a/xlators/cluster/afr/src/afr-open.c b/xlators/cluster/afr/src/afr-open.c
new file mode 100644
index 000000000..945f5cddf
--- /dev/null
+++ b/xlators/cluster/afr/src/afr-open.c
@@ -0,0 +1,356 @@
+/*
+   Copyright (c) 2007-2009 Gluster, Inc. <http://www.gluster.com>
+   This file is part of GlusterFS.
+
+   GlusterFS is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3 of the License,
+   or (at your option) any later version.
+
+   GlusterFS is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see
+   <http://www.gnu.org/licenses/>.
+*/
+
+#include <libgen.h>
+#include <unistd.h>
+#include <fnmatch.h>
+#include <sys/time.h>
+#include <stdlib.h>
+#include <signal.h>
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glusterfs.h"
+#include "afr.h"
+#include "dict.h"
+#include "xlator.h"
+#include "hashfn.h"
+#include "logging.h"
+#include "stack.h"
+#include "list.h"
+#include "call-stub.h"
+#include "defaults.h"
+#include "common-utils.h"
+#include "compat-errno.h"
+#include "compat.h"
+#include "byte-order.h"
+#include "statedump.h"
+
+#include "fd.h"
+
+#include "afr-inode-read.h"
+#include "afr-inode-write.h"
+#include "afr-dir-read.h"
+#include "afr-dir-write.h"
+#include "afr-transaction.h"
+
+#include "afr-self-heal.h"
+
+
+int
+afr_open_ftruncate_cbk (call_frame_t *frame, void *cookie, xlator_t *this, 
+			int32_t op_ret, int32_t op_errno, struct stat *prebuf,
+                        struct stat *postbuf)
+{
+	afr_local_t * local = frame->local;
+        int ret = 0;
+
+        ret = afr_fd_ctx_set (this, local->fd);
+
+        if (ret < 0) {
+                local->op_ret   =   -1;
+                local->op_errno = -ret;
+        }
+
+	AFR_STACK_UNWIND (open, frame, local->op_ret, local->op_errno,
+			  local->fd);
+	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)
+{
+	afr_local_t *  local = NULL;
+	afr_private_t * priv = NULL;
+
+        int ret = 0;
+
+	int call_count = -1;
+
+	priv  = this->private;
+	local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		if (op_ret == -1) {
+			local->op_errno = op_errno;
+		}
+
+		if (op_ret >= 0) {
+			local->op_ret = op_ret;
+                        local->success_count++;
+		}
+	}
+	UNLOCK (&frame->lock);
+
+	call_count = afr_frame_return (frame);
+
+	if (call_count == 0) {
+		if ((local->cont.open.flags & O_TRUNC)
+		    && (local->op_ret >= 0)) {
+			STACK_WIND (frame, afr_open_ftruncate_cbk,
+				    this, this->fops->ftruncate,
+				    fd, 0);
+		} else {
+                        ret = afr_fd_ctx_set (this, fd);
+
+                        if (ret < 0) {
+                                gf_log (this->name, GF_LOG_DEBUG,
+                                        "could not set fd ctx for fd=%p",
+                                        fd);
+
+                                local->op_ret   = -1;
+                                local->op_errno = -ret;
+                        }
+
+                        AFR_STACK_UNWIND (open, frame, local->op_ret,
+                                          local->op_errno, local->fd);
+		}
+	}
+
+	return 0;
+}
+
+
+int
+afr_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+          fd_t *fd, int32_t wbflags)
+{
+	afr_private_t * priv  = NULL;
+	afr_local_t *   local = NULL;
+
+	int     i = 0;
+	int   ret = -1;
+
+	int32_t call_count = 0;	
+	int32_t op_ret   = -1;
+	int32_t op_errno = 0;
+	int32_t wind_flags = flags & (~O_TRUNC);
+
+	VALIDATE_OR_GOTO (frame, out);
+	VALIDATE_OR_GOTO (this, out);
+	VALIDATE_OR_GOTO (this->private, out);
+	VALIDATE_OR_GOTO (loc, out);
+
+	priv = this->private;
+
+        if (afr_is_split_brain (this, loc->inode)) {
+		/* self-heal failed */
+		op_errno = EIO;
+		goto out;
+	}
+
+	ALLOC_OR_GOTO (local, afr_local_t, out);
+
+	ret = AFR_LOCAL_INIT (local, priv);
+	if (ret < 0) {
+		op_errno = -ret;
+		goto out;
+	}
+
+	frame->local = local;
+	call_count   = local->call_count;
+
+	local->cont.open.flags = flags;
+	local->fd = fd_ref (fd);
+
+	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, wind_flags, fd, wbflags);
+
+			if (!--call_count)
+				break;
+		}
+	}
+
+	op_ret = 0;
+out:
+	if (op_ret == -1) {
+		AFR_STACK_UNWIND (open, frame, op_ret, op_errno, fd);
+	}
+
+	return 0;
+}
+
+
+int
+afr_up_down_flush_sh_completion_cbk (call_frame_t *frame, xlator_t *this)
+{
+        afr_local_t *local = NULL;
+
+        local = frame->local;
+
+        local->transaction.post_post_op (frame, this);
+
+        return 0;
+}
+
+
+int
+afr_up_down_flush_post_post_op (call_frame_t *frame, xlator_t *this)
+{
+        afr_private_t *priv = NULL;
+        afr_local_t *local  = NULL;
+        afr_self_heal_t *sh = NULL;
+
+        priv  = this->private;
+        local = frame->local;
+        sh    = &local->self_heal;
+
+        sh->calling_fop = GF_FOP_FLUSH;
+
+//        sh->healing_fd = local->fd;
+
+//        sh->healing_fd_opened = _gf_true;
+
+        local->cont.lookup.inode = local->fd->inode;
+
+        inode_path (local->fd->inode, NULL, (char **)&local->loc.path);
+        local->loc.name   = strrchr (local->loc.path, '/');
+        local->loc.inode  = inode_ref (local->fd->inode);
+        local->loc.parent = inode_parent (local->fd->inode, 0, NULL);
+
+        sh->data_lock_held    = _gf_true;
+
+        local->need_data_self_heal     = _gf_true;
+        local->cont.lookup.buf.st_mode = local->fd->inode->st_mode;
+        local->child_count             = afr_up_children_count (priv->child_count,
+                                                                local->child_up);
+
+        sh->flush_self_heal_cbk = afr_up_down_flush_sh_completion_cbk;
+
+        afr_self_heal (frame, this, afr_up_down_flush_sh_completion_cbk,
+                       _gf_false);
+
+        return 0;
+}
+
+
+int
+afr_up_down_flush_wind (call_frame_t *frame, xlator_t *this)
+{
+	afr_local_t *local = NULL;
+	afr_private_t *priv = NULL;
+
+	local = frame->local;
+	priv  = this->private;
+
+        local->transaction.resume (frame, this);
+	return 0;
+}
+
+
+int
+afr_up_down_flush_done (call_frame_t *frame, xlator_t *this)
+{
+        afr_private_t *priv = NULL;
+	afr_local_t *local  = NULL;
+
+        uint64_t       ctx;
+        afr_fd_ctx_t * fd_ctx = NULL;
+
+        int _ret = -1;
+        int i    = 0;
+
+        priv  = this->private;
+	local = frame->local;
+
+        LOCK (&local->fd->lock);
+        {
+                _ret = __fd_ctx_get (local->fd, this, &ctx);
+
+                if (_ret < 0) {
+                        goto out;
+                }
+
+                fd_ctx = (afr_fd_ctx_t *)(long) ctx;
+
+                fd_ctx->down_count = priv->down_count;
+                fd_ctx->up_count   = priv->up_count;
+
+                for (i = 0; i < priv->child_count; i++) {
+                        if (local->child_up[i])
+                                fd_ctx->pre_op_done[i] = 0;
+                }
+        }
+out:
+        UNLOCK (&local->fd->lock);
+
+        local->up_down_flush_cbk (frame, this);
+
+	return 0;
+}
+
+
+int
+afr_up_down_flush (call_frame_t *frame, xlator_t *this, fd_t *fd,
+                   afr_flush_type type)
+{
+	afr_private_t * priv  = NULL;
+	afr_local_t   * local = NULL;
+
+	int op_ret   = -1;
+
+	VALIDATE_OR_GOTO (frame, out);
+	VALIDATE_OR_GOTO (this, out);
+	VALIDATE_OR_GOTO (this->private, out);
+
+	priv = this->private;
+
+        local = frame->local;
+
+        local->op = GF_FOP_FLUSH;
+
+        local->fd = fd_ref (local->fd);
+
+        local->transaction.fop          = afr_up_down_flush_wind;
+        local->transaction.done         = afr_up_down_flush_done;
+
+        switch (type) {
+        case AFR_CHILD_UP_FLUSH:
+                local->transaction.post_post_op = afr_up_down_flush_post_post_op;
+                break;
+
+        case AFR_CHILD_DOWN_FLUSH:
+                local->transaction.post_post_op = NULL;
+                break;
+        }
+
+        local->transaction.start  = 0;
+        local->transaction.len    = 0;
+
+        gf_log (this->name, GF_LOG_TRACE,
+                "doing up/down flush on fd=%p",
+                fd);
+
+        afr_transaction (frame, this, AFR_FLUSH_TRANSACTION);
+
+	op_ret = 0;
+out:
+	return 0;
+}