orangefs: implement xattr cache

This uses the same timeout as the getattr cache.  This substantially
increases performance when writing files with smaller buffer sizes.

When writing, the size is (often) changed, which causes a call to
notify_change which calls security_inode_need_killpriv which needs a
getxattr.  Caching it reduces traffic to the server.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

fs/orangefs/inode.c

@@ -364,6 +364,7 @@ static int orangefs_set_inode(struct inode *inode, void *data)
 	struct orangefs_object_kref *ref = (struct orangefs_object_kref *) data;
 	ORANGEFS_I(inode)->refn.fs_id = ref->fs_id;
 	ORANGEFS_I(inode)->refn.khandle = ref->khandle;
+	hash_init(ORANGEFS_I(inode)->xattr_cache);
 	return 0;
 }
 

fs/orangefs/orangefs-kernel.h

@@ -51,6 +51,7 @@
 #include <linux/rwsem.h>
 #include <linux/xattr.h>
 #include <linux/exportfs.h>
+#include <linux/hashtable.h>
 
 #include <asm/unaligned.h>
 
@@ -193,6 +194,8 @@ struct orangefs_inode_s {
 
 	unsigned long getattr_time;
 	u32 getattr_mask;
+
+	DECLARE_HASHTABLE(xattr_cache, 4);
 };
 
 /* per superblock private orangefs info */
@@ -217,6 +220,14 @@ struct orangefs_stats {
 	unsigned long writes;
 };
 
+struct orangefs_cached_xattr {
+	struct hlist_node node;
+	char key[ORANGEFS_MAX_XATTR_NAMELEN];
+	char val[ORANGEFS_MAX_XATTR_VALUELEN];
+	ssize_t length;
+	unsigned long timeout;
+};
+
 extern struct orangefs_stats orangefs_stats;
 
 /*

fs/orangefs/super.c

@@ -10,6 +10,7 @@
 #include "orangefs-bufmap.h"
 
 #include <linux/parser.h>
+#include <linux/hashtable.h>
 
 /* a cache for orangefs-inode objects (i.e. orangefs inode private data) */
 static struct kmem_cache *orangefs_inode_cache;
@@ -128,6 +129,15 @@ static void orangefs_i_callback(struct rcu_head *head)
 {
 	struct inode *inode = container_of(head, struct inode, i_rcu);
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
+	struct orangefs_cached_xattr *cx;
+	struct hlist_node *tmp;
+	int i;
+
+	hash_for_each_safe(orangefs_inode->xattr_cache, i, tmp, cx, node) {
+		hlist_del(&cx->node);
+		kfree(cx);
+	}
+
 	kmem_cache_free(orangefs_inode_cache, orangefs_inode);
 }
 

fs/orangefs/xattr.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * (C) 2001 Clemson University and The University of Chicago
+ * Copyright 2018 Omnibond Systems, L.L.C.
  *
  * See COPYING in top-level directory.
  */
@@ -14,7 +15,7 @@
 #include "orangefs-bufmap.h"
 #include <linux/posix_acl_xattr.h>
 #include <linux/xattr.h>
-
+#include <linux/hashtable.h>
 
 #define SYSTEM_ORANGEFS_KEY "system.pvfs2."
 #define SYSTEM_ORANGEFS_KEY_LEN 13
@@ -50,6 +51,35 @@ static inline int convert_to_internal_xattr_flags(int setxattr_flags)
 	return internal_flag;
 }
 
+static unsigned int xattr_key(const char *key)
+{
+	unsigned int i = 0;
+	while (key)
+		i += *key++;
+	return i % 16;
+}
+
+static struct orangefs_cached_xattr *find_cached_xattr(struct inode *inode,
+    const char *key)
+{
+	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
+	struct orangefs_cached_xattr *cx;
+	struct hlist_head *h;
+	struct hlist_node *tmp;
+	h = &orangefs_inode->xattr_cache[xattr_key(key)];
+	if (hlist_empty(h))
+		return NULL;
+	hlist_for_each_entry_safe(cx, tmp, h, node) {
+/*		if (!time_before(jiffies, cx->timeout)) {
+			hlist_del(&cx->node);
+			kfree(cx);
+			continue;
+		}*/
+		if (!strcmp(cx->key, key))
+			return cx;
+	}
+	return NULL;
+}
 
 /*
  * Tries to get a specified key's attributes of a given
@@ -65,6 +95,7 @@ ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
 {
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_kernel_op_s *new_op = NULL;
+	struct orangefs_cached_xattr *cx;
 	ssize_t ret = -ENOMEM;
 	ssize_t length = 0;
 	int fsuid;
@@ -93,6 +124,27 @@ ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
 
 	down_read(&orangefs_inode->xattr_sem);
 
+	cx = find_cached_xattr(inode, name);
+	if (cx && time_before(jiffies, cx->timeout)) {
+		if (cx->length == -1) {
+			ret = -ENODATA;
+			goto out_unlock;
+		} else {
+			if (size == 0) {
+				ret = cx->length;
+				goto out_unlock;
+			}
+			if (cx->length > size) {
+				ret = -ERANGE;
+				goto out_unlock;
+			}
+			memcpy(buffer, cx->val, cx->length);
+			memset(buffer + cx->length, 0, size - cx->length);
+			ret = cx->length;
+			goto out_unlock;
+		}
+	}
+
 	new_op = op_alloc(ORANGEFS_VFS_OP_GETXATTR);
 	if (!new_op)
 		goto out_unlock;
@@ -117,6 +169,15 @@ ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
 				     " does not exist!\n",
 				     get_khandle_from_ino(inode),
 				     (char *)new_op->upcall.req.getxattr.key);
+			cx = kmalloc(sizeof *cx, GFP_KERNEL);
+			if (cx) {
+				strcpy(cx->key, name);
+				cx->length = -1;
+				cx->timeout = jiffies +
+				    orangefs_getattr_timeout_msecs*HZ/1000;
+				hash_add(orangefs_inode->xattr_cache, &cx->node,
+				    xattr_key(cx->key));
+			}
 		}
 		goto out_release_op;
 	}
@@ -156,6 +217,23 @@ ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
 
 	ret = length;
 
+	if (cx) {
+		strcpy(cx->key, name);
+		memcpy(cx->val, buffer, length);
+		cx->length = length;
+		cx->timeout = jiffies + HZ;
+	} else {
+		cx = kmalloc(sizeof *cx, GFP_KERNEL);
+		if (cx) {
+			strcpy(cx->key, name);
+			memcpy(cx->val, buffer, length);
+			cx->length = length;
+			cx->timeout = jiffies + HZ;
+			hash_add(orangefs_inode->xattr_cache, &cx->node,
+			    xattr_key(cx->key));
+		}
+	}
+
 out_release_op:
 	op_release(new_op);
 out_unlock:
@@ -168,6 +246,9 @@ static int orangefs_inode_removexattr(struct inode *inode, const char *name,
 {
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_kernel_op_s *new_op = NULL;
+	struct orangefs_cached_xattr *cx;
+	struct hlist_head *h;
+	struct hlist_node *tmp;
 	int ret = -ENOMEM;
 
 	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
@@ -209,6 +290,16 @@ static int orangefs_inode_removexattr(struct inode *inode, const char *name,
 		     "orangefs_inode_removexattr: returning %d\n", ret);
 
 	op_release(new_op);
+
+	h = &orangefs_inode->xattr_cache[xattr_key(name)];
+	hlist_for_each_entry_safe(cx, tmp, h, node) {
+		if (!strcmp(cx->key, name)) {
+			hlist_del(&cx->node);
+			kfree(cx);
+			break;
+		}
+	}
+
 out_unlock:
 	up_write(&orangefs_inode->xattr_sem);
 	return ret;
@@ -226,6 +317,9 @@ int orangefs_inode_setxattr(struct inode *inode, const char *name,
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_kernel_op_s *new_op;
 	int internal_flag = 0;
+	struct orangefs_cached_xattr *cx;
+	struct hlist_head *h;
+	struct hlist_node *tmp;
 	int ret = -ENOMEM;
 
 	gossip_debug(GOSSIP_XATTR_DEBUG,
@@ -287,6 +381,16 @@ int orangefs_inode_setxattr(struct inode *inode, const char *name,
 
 	/* when request is serviced properly, free req op struct */
 	op_release(new_op);
+
+	h = &orangefs_inode->xattr_cache[xattr_key(name)];
+	hlist_for_each_entry_safe(cx, tmp, h, node) {
+		if (!strcmp(cx->key, name)) {
+			hlist_del(&cx->node);
+			kfree(cx);
+			break;
+		}
+	}
+
 out_unlock:
 	up_write(&orangefs_inode->xattr_sem);
 	return ret;