[PATCH 06/24] orangefs: implement xattr cache

From: Martin Brandenburg <martin@omnibond.com>
To: hubcap@omnibond.com, linux-fsdevel@vger.kernel.org
Cc: Martin Brandenburg <martin@omnibond.com>
Subject: [PATCH 06/24] orangefs: implement xattr cache
Date: Tue, 20 Mar 2018 17:02:16 +0000	[thread overview]
Message-ID: <20180320170234.1412-7-martin@omnibond.com> (raw)
In-Reply-To: <20180320170234.1412-1-martin@omnibond.com>

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>
---
 fs/orangefs/inode.c           |  1 +
 fs/orangefs/orangefs-kernel.h | 10 +++++
 fs/orangefs/super.c           |  9 ++++
 fs/orangefs/xattr.c           | 97 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 117 insertions(+)

diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
index a922c9da80d6..26381d451039 100644
--- a/fs/orangefs/inode.c
+++ b/fs/orangefs/inode.c
@@ -363,6 +363,7 @@ 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;
 }
 
diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
index 4f26fcbb9c83..b2046d29a116 100644
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -195,6 +195,8 @@ struct orangefs_inode_s {
 
 	unsigned long getattr_time;
 	u32 getattr_mask;
+
+	DECLARE_HASHTABLE(xattr_cache, 4);
 };
 
 /* per superblock private orangefs info */
@@ -219,6 +221,14 @@ 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;
 
 /*
diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index 6183f6f6db53..b7718530bde4 100644
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -127,6 +127,15 @@ 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);
 }
 
diff --git a/fs/orangefs/xattr.c b/fs/orangefs/xattr.c
index b3b0db56b408..59bd382eb6dc 100644
--- a/fs/orangefs/xattr.c
+++ b/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.
  */
@@ -49,6 +50,35 @@ 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
@@ -64,6 +94,7 @@ 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;
@@ -92,6 +123,27 @@ 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) {
+		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_release_op;
+			}
+			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;
@@ -116,6 +168,15 @@ 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;
 	}
@@ -155,6 +216,16 @@ ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
 
 	ret = length;
 
+	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:
@@ -167,6 +238,9 @@ 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)
@@ -208,6 +282,16 @@ 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;
@@ -225,6 +309,9 @@ 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,
@@ -286,6 +373,16 @@ 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;
-- 
2.16.2
