Implemented entry locks and support for domains.

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

BUG: 222 (Enhance Internal locks to support multilple domains and rewrite inodelks)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=222

1 files changed, 577 insertions, 0 deletions

diff --git a/xlators/features/locks/src/entrylk.c b/xlators/features/locks/src/entrylk.c
new file mode 100644
index 00000000000..0ddc9532fba
--- /dev/null
+++ b/xlators/features/locks/src/entrylk.c
@@ -0,0 +1,577 @@
+/*
+  Copyright (c) 2006, 2007, 2008 Z RESEARCH, Inc. <http://www.zresearch.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/>.
+*/
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glusterfs.h"
+#include "compat.h"
+#include "xlator.h"
+#include "inode.h"
+#include "logging.h"
+#include "common-utils.h"
+#include "list.h"
+
+#include "locks.h"
+#include "common.h"
+
+static pl_entry_lock_t *
+new_entrylk_lock (pl_inode_t *pinode, const char *basename, entrylk_type type,
+		  transport_t *trans, pid_t client_pid, const char *volume)
+{
+	pl_entry_lock_t *newlock = NULL;
+
+	newlock = CALLOC (1, sizeof (pl_entry_lock_t));
+	if (!newlock) {
+		goto out;
+	}
+
+	newlock->basename       = basename ? strdup (basename) : NULL;
+	newlock->type           = type;
+	newlock->trans          = trans;
+	newlock->volume         = volume;
+        newlock->client_pid     = client_pid;
+
+
+	INIT_LIST_HEAD (&newlock->domain_list);
+	INIT_LIST_HEAD (&newlock->blocked_locks);
+
+out:
+	return newlock;
+}
+
+
+/**
+ * all_names - does a basename represent all names?
+ * @basename: name to check
+ */
+
+#define all_names(basename) ((basename == NULL) ? 1 : 0)
+
+/**
+ * names_conflict - do two names conflict?
+ * @n1: name
+ * @n2: name
+ */
+
+static int
+names_conflict (const char *n1, const char *n2)
+{
+	return all_names (n1) || all_names (n2) || !strcmp (n1, n2);
+}
+
+
+static int
+__same_entrylk_owner (pl_entry_lock_t *l1, pl_entry_lock_t *l2)
+{
+        return ((l1->client_pid == l2->client_pid) &&
+		(l1->trans  == l2->trans));
+}
+
+
+/**
+ * lock_grantable - is this lock grantable?
+ * @inode: inode in which to look
+ * @basename: name we're trying to lock
+ * @type: type of lock
+ */
+static pl_entry_lock_t *
+__lock_grantable (pl_dom_list_t *dom, const char *basename, entrylk_type type)
+{
+	pl_entry_lock_t *lock = NULL;
+
+	if (list_empty (&dom->entrylk_list))
+		return NULL;
+
+	list_for_each_entry (lock, &dom->entrylk_list, domain_list) {
+		if (names_conflict (lock->basename, basename))
+			return lock;
+	}
+
+	return NULL;
+}
+
+static pl_entry_lock_t *
+__blocked_lock_conflict (pl_dom_list_t *dom, const char *basename, entrylk_type type)
+{
+	pl_entry_lock_t *lock = NULL;
+
+	if (list_empty (&dom->blocked_entrylks))
+		return NULL;
+
+	list_for_each_entry (lock, &dom->blocked_entrylks, blocked_locks) {
+		if (names_conflict (lock->basename, basename))
+			return lock;
+	}
+
+	return NULL;
+}
+
+static int
+__owner_has_lock (pl_dom_list_t *dom, pl_entry_lock_t *newlock)
+{
+        pl_entry_lock_t *lock = NULL;
+
+	list_for_each_entry (lock, &dom->entrylk_list, domain_list) {
+		if (__same_entrylk_owner (lock, newlock))
+			return 1;
+	}
+
+	list_for_each_entry (lock, &dom->blocked_entrylks, blocked_locks) {
+		if (__same_entrylk_owner (lock, newlock))
+			return 1;
+	}
+
+	return 0;
+}
+
+static int
+names_equal (const char *n1, const char *n2)
+{
+	return (n1 == NULL && n2 == NULL) || (n1 && n2 && !strcmp (n1, n2));
+}
+
+/**
+ * __find_most_matching_lock - find the lock struct which most matches in order of:
+ *                           lock on the exact basename ||
+ *                           an all_names lock
+ *
+ *
+ * @inode: inode in which to look
+ * @basename: name to search for
+ */
+
+static pl_entry_lock_t *
+__find_most_matching_lock (pl_dom_list_t *dom, const char *basename)
+{
+	pl_entry_lock_t *lock;
+	pl_entry_lock_t *all = NULL;
+	pl_entry_lock_t *exact = NULL;
+
+	if (list_empty (&dom->entrylk_list))
+		return NULL;
+
+	list_for_each_entry (lock, &dom->entrylk_list, domain_list) {
+		if (all_names (lock->basename))
+			all = lock;
+		else if (names_equal (lock->basename, basename))
+			exact = lock;
+	}
+
+	return (exact ? exact : all);
+}
+
+/**
+ * __lock_name - lock a name in a directory
+ * @inode: inode for the directory in which to lock
+ * @basename: name of the entry to lock
+ *            if null, lock the entire directory
+ *
+ * the entire directory being locked is represented as: a single
+ * pl_entry_lock_t present in the entrylk_locks list with its
+ * basename = NULL
+ */
+
+int
+__lock_name (pl_inode_t *pinode, const char *basename, entrylk_type type,
+	     call_frame_t *frame, pl_dom_list_t *dom, xlator_t *this, int nonblock)
+{
+	pl_entry_lock_t *lock    = NULL;
+	pl_entry_lock_t *conf    = NULL;
+	transport_t     *trans   = NULL;
+        pid_t        client_pid = 0;
+
+	int ret = -EINVAL;
+
+	trans = frame->root->trans;
+        client_pid = frame->root->pid;
+
+	lock = new_entrylk_lock (pinode, basename, type, trans, client_pid, dom->domain);
+	if (!lock) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	conf = __lock_grantable (dom, basename, type);
+	if (conf) {
+		ret = -EAGAIN;
+		if (nonblock)
+			goto out;
+
+		lock->frame   = frame;
+		lock->this    = this;
+
+		list_add_tail (&lock->blocked_locks, &dom->blocked_entrylks);
+
+		gf_log (this->name, GF_LOG_TRACE,
+			"Blocking lock: {pinode=%p, basename=%s}",
+			pinode, basename);
+
+		goto out;
+	}
+
+        if ( __blocked_lock_conflict (dom, basename, type) && !(__owner_has_lock (dom, lock))) {
+                ret = -EAGAIN;
+                if (nonblock)
+                        goto out;
+                lock->frame     = frame;
+                lock->this      = this;
+
+                list_add_tail (&lock->blocked_locks, &dom->blocked_entrylks);
+
+                gf_log (this->name, GF_LOG_TRACE,
+                        "Lock is grantable, but blocking to prevent starvation");
+		gf_log (this->name, GF_LOG_TRACE,
+			"Blocking lock: {pinode=%p, basename=%s}",
+			pinode, basename);
+
+		goto out;
+        }
+        switch (type) {
+
+	case ENTRYLK_WRLCK:
+		list_add (&lock->domain_list, &dom->entrylk_list);
+		break;
+
+        default:
+
+          gf_log (this->name, GF_LOG_DEBUG,
+                  "Invalid type for entrylk specified: %d", type);
+          ret = -EINVAL;
+          goto out;
+	}
+
+	ret = 0;
+out:
+	return ret;
+}
+
+/**
+ * __unlock_name - unlock a name in a directory
+ * @inode: inode for the directory to unlock in
+ * @basename: name of the entry to unlock
+ *            if null, unlock the entire directory
+ */
+
+pl_entry_lock_t *
+__unlock_name (pl_dom_list_t *dom, const char *basename, entrylk_type type)
+{
+	pl_entry_lock_t *lock = NULL;
+	pl_entry_lock_t *ret_lock = NULL;
+
+	lock = __find_most_matching_lock (dom, basename);
+
+	if (!lock) {
+		gf_log ("locks", GF_LOG_DEBUG,
+			"unlock on %s (type=ENTRYLK_WRLCK) attempted but no matching lock found",
+			basename);
+		goto out;
+	}
+
+	if (names_equal (lock->basename, basename)
+	    && lock->type == type) {
+
+		if (type == ENTRYLK_WRLCK) {
+			list_del (&lock->domain_list);
+			ret_lock = lock;
+		}
+	} else {
+		gf_log ("locks", GF_LOG_DEBUG,
+			"Unlock for a non-existing lock!");
+		goto out;
+	}
+
+out:
+	return ret_lock;
+}
+
+
+void
+__grant_blocked_entry_locks (xlator_t *this, pl_inode_t *pl_inode,
+			     pl_dom_list_t *dom, struct list_head *granted)
+{
+	int              bl_ret = 0;
+	pl_entry_lock_t *bl   = NULL;
+	pl_entry_lock_t *tmp  = NULL;
+
+	list_for_each_entry_safe (bl, tmp, &dom->blocked_entrylks,
+				  blocked_locks) {
+
+                if (__lock_grantable (dom, bl->basename, bl->type))
+                        continue;
+
+		list_del_init (&bl->blocked_locks);
+
+		/* TODO: error checking */
+
+		gf_log ("locks", GF_LOG_TRACE,
+			"Trying to unblock: {pinode=%p, basename=%s}",
+			pl_inode, bl->basename);
+
+		bl_ret = __lock_name (pl_inode, bl->basename, bl->type,
+				      bl->frame, dom, bl->this, 0);
+
+		if (bl_ret == 0) {
+			list_add (&bl->blocked_locks, granted);
+		} else {
+			if (bl->basename)
+				FREE (bl->basename);
+			FREE (bl);
+		}
+	}
+	return;
+}
+
+/* Grants locks if possible which are blocked on a lock */
+void
+grant_blocked_entry_locks (xlator_t *this, pl_inode_t *pl_inode,
+			   pl_entry_lock_t *unlocked, pl_dom_list_t *dom)
+{
+	struct list_head  granted_list;
+	pl_entry_lock_t  *tmp = NULL;
+	pl_entry_lock_t  *lock = NULL;
+
+	INIT_LIST_HEAD (&granted_list);
+
+	pthread_mutex_lock (&pl_inode->mutex);
+	{
+		__grant_blocked_entry_locks (this, pl_inode, dom, &granted_list);
+	}
+	pthread_mutex_unlock (&pl_inode->mutex);
+
+	list_for_each_entry_safe (lock, tmp, &granted_list, blocked_locks) {
+		list_del_init (&lock->blocked_locks);
+
+		STACK_UNWIND (lock->frame, 0, 0);
+
+		FREE (lock->basename);
+		FREE (lock);
+	}
+
+	FREE (unlocked->basename);
+	FREE (unlocked);
+
+	return;
+}
+
+/**
+ * release_entry_locks_for_transport: release all entry locks from this
+ * transport for this loc_t
+ */
+
+static int
+release_entry_locks_for_transport (xlator_t *this, pl_inode_t *pinode,
+				   pl_dom_list_t *dom, transport_t *trans)
+{
+	pl_entry_lock_t  *lock = NULL;
+	pl_entry_lock_t  *tmp = NULL;
+	struct list_head  granted;
+
+	INIT_LIST_HEAD (&granted);
+
+	pthread_mutex_lock (&pinode->mutex);
+	{
+		if (list_empty (&dom->entrylk_list)) {
+			goto unlock;
+		}
+
+		list_for_each_entry_safe (lock, tmp, &dom->entrylk_list,
+					  domain_list) {
+			if (lock->trans != trans)
+				continue;
+
+			list_del_init (&lock->domain_list);
+
+			gf_log (this->name, GF_LOG_TRACE,
+                                "releasing lock on  held by "
+                                "{transport=%p}",trans);;
+
+			FREE (lock->basename);
+			FREE (lock);
+		}
+
+		__grant_blocked_entry_locks (this, pinode, dom, &granted);
+
+	}
+unlock:
+	pthread_mutex_unlock (&pinode->mutex);
+
+	list_for_each_entry_safe (lock, tmp, &granted, blocked_locks) {
+		list_del_init (&lock->blocked_locks);
+
+		STACK_UNWIND (lock->frame, 0, 0);
+
+		if (lock->basename)
+			FREE (lock->basename);
+		FREE (lock);
+	}
+
+	return 0;
+}
+
+/* Common entrylk code called by pl_entrylk and pl_fentrylk */
+int
+pl_common_entrylk (call_frame_t *frame, xlator_t *this,
+	    const char *volume, inode_t *inode, const char *basename,
+	    entrylk_cmd cmd, entrylk_type type)
+{
+	int32_t op_ret   = -1;
+	int32_t op_errno = 0;
+
+	transport_t * transport = NULL;
+	pid_t pid = -1;
+
+	pl_inode_t *       pinode = NULL;
+	int                ret    = -1;
+	pl_entry_lock_t   *unlocked = NULL;
+	char               unwind = 1;
+
+	pl_dom_list_t	  *dom = NULL;
+
+	pinode = pl_inode_get (this, inode);
+	if (!pinode) {
+		gf_log (this->name, GF_LOG_ERROR,
+			"Out of memory.");
+		op_errno = ENOMEM;
+		goto out;
+	}
+
+	dom = get_domain (pinode, volume);
+	if (!dom){
+		gf_log ("posix-locks", GF_LOG_ERROR,
+			"Out of memory");
+		op_errno = ENOMEM;
+		goto out;
+	}
+
+	pid       = frame->root->pid;
+	transport = frame->root->trans;
+
+	if (pid == 0) {
+		/*
+		   this is a special case that means release
+		   all locks from this transport
+		*/
+
+		gf_log (this->name, GF_LOG_TRACE,
+			"Releasing locks for transport %p", transport);
+
+		release_entry_locks_for_transport (this, pinode, dom, transport);
+		op_ret = 0;
+
+		goto out;
+	}
+
+	switch (cmd) {
+	case ENTRYLK_LOCK:
+		pthread_mutex_lock (&pinode->mutex);
+		{
+			ret = __lock_name (pinode, basename, type,
+					   frame, dom, this, 0);
+		}
+		pthread_mutex_unlock (&pinode->mutex);
+
+		if (ret < 0) {
+			if (ret == -EAGAIN)
+				unwind = 0;
+			op_errno = -ret;
+			goto out;
+		}
+
+		break;
+
+	case ENTRYLK_LOCK_NB:
+		pthread_mutex_lock (&pinode->mutex);
+		{
+			ret = __lock_name (pinode, basename, type,
+					   frame, dom, this, 1);
+		}
+		pthread_mutex_unlock (&pinode->mutex);
+
+		if (ret < 0) {
+			op_errno = -ret;
+			goto out;
+		}
+
+		break;
+
+	case ENTRYLK_UNLOCK:
+		pthread_mutex_lock (&pinode->mutex);
+		{
+			 unlocked = __unlock_name (dom, basename, type);
+		}
+		pthread_mutex_unlock (&pinode->mutex);
+
+		if (unlocked)
+			grant_blocked_entry_locks (this, pinode, unlocked, dom);
+
+		break;
+
+	default:
+		gf_log (this->name, GF_LOG_ERROR,
+			"Unexpected case in entrylk (cmd=%d). Please file"
+                        "a bug report at http://bugs.gluster.com", cmd);
+		goto out;
+	}
+
+	op_ret = 0;
+out:
+	if (unwind) {
+		STACK_UNWIND (frame, op_ret, op_errno);
+	}
+
+	return 0;
+}
+
+/**
+ * pl_entrylk:
+ *
+ * Locking on names (directory entries)
+ */
+
+int
+pl_entrylk (call_frame_t *frame, xlator_t *this,
+	    const char *volume, loc_t *loc, const char *basename,
+	    entrylk_cmd cmd, entrylk_type type)
+{
+
+  pl_common_entrylk (frame, this, volume, loc->inode, basename, cmd, type);
+
+  return 0;
+}
+
+
+/**
+ * pl_fentrylk:
+ *
+ * Locking on names (directory entries)
+ */
+
+int
+pl_fentrylk (call_frame_t *frame, xlator_t *this,
+	     const char *volume, fd_t *fd, const char *basename,
+	     entrylk_cmd cmd, entrylk_type type)
+{
+
+  pl_common_entrylk (frame, this, volume, fd->inode, basename, cmd, type);
+
+	return 0;
+}