Prev: [GIT PULL] ocfs2 changes for 2.6.36, part 1.
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From: bchociej on 12 Aug 2010 18:30
From: Ben Chociej <bchociej(a)gmail.com>

Add a /sys/kernel/debug/btrfs_data/<device_name>/ directory for each
volume that contains two files. The first, `inode_data', contains the
heat information for inodes that have been brought into the hot data map
structures. The second, `range_data', contains similar information for
subfile ranges.

Signed-off-by: Matt Lupfer <mlupfer(a)gmail.com>
Signed-off-by: Conor Scott <conscott(a)vt.edu>
Signed-off-by: Ben Chociej <bchociej(a)gmail.com>
Reviewed-by: Mingming Cao <cmm(a)us.ibm.com>
---
fs/btrfs/debugfs.c | 532 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/debugfs.h | 89 +++++++++
2 files changed, 621 insertions(+), 0 deletions(-)
create mode 100644 fs/btrfs/debugfs.c
create mode 100644 fs/btrfs/debugfs.h

diff --git a/fs/btrfs/debugfs.c b/fs/btrfs/debugfs.c
new file mode 100644
index 0000000..c11c0b6
--- /dev/null
+++ b/fs/btrfs/debugfs.c
@@ -0,0 +1,532 @@
+/*
+ * fs/btrfs/debugfs.c
+ *
+ * This file contains the code to interface with the btrfs debugfs.
+ * The debugfs outputs range- and file-level access frequency
+ * statistics for each mounted volume.
+ *
+ * Copyright (C) 2010 International Business Machines Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <linux/limits.h>
+#include "ctree.h"
+#include "hotdata_map.h"
+#include "hotdata_hash.h"
+#include "hotdata_relocate.h"
+#include "debugfs.h"
+
+static int copy_msg_to_log(struct debugfs_vol_data *data, char *msg, int len)
+{
+ struct lstring *debugfs_log = data->debugfs_log;
+ uint new_log_alloc_size;
+ char *new_log;
+
+ if (len >= data->log_alloc_size - debugfs_log->len) {
+ /* Not enough room in the log buffer for the new message. */
+ /* Allocate a bigger buffer. */
+ new_log_alloc_size = data->log_alloc_size + LOG_PAGE_SIZE;
+ new_log = vmalloc(new_log_alloc_size);
+
+ if (new_log) {
+ memcpy(new_log, debugfs_log->str,
+ debugfs_log->len);
+ memset(new_log + debugfs_log->len, 0,
+ new_log_alloc_size - debugfs_log->len);
+ vfree(debugfs_log->str);
+ debugfs_log->str = new_log;
+ data->log_alloc_size = new_log_alloc_size;
+ } else {
+ WARN_ON(1);
+ if (data->log_alloc_size - debugfs_log->len) {
+ #define err_msg "No more memory!\n"
+ strlcpy(debugfs_log->str +
+ debugfs_log->len,
+ err_msg, data->log_alloc_size -
+ debugfs_log->len);
+ debugfs_log->len +=
+ min((typeof(debugfs_log->len))
+ sizeof(err_msg),
+ ((typeof(debugfs_log->len))
+ data->log_alloc_size -
+ debugfs_log->len));
+ }
+ return 0;
+ }
+ }
+
+ memcpy(debugfs_log->str + debugfs_log->len,
+ data->log_work_buff, len);
+ debugfs_log->len += (unsigned long) len;
+
+ return len;
+}
+
+/* Returns the number of bytes written to the log. */
+static int debugfs_log(struct debugfs_vol_data *data, const char *fmt, ...)
+{
+ struct lstring *debugfs_log = data->debugfs_log;
+ va_list args;
+ int len;
+
+ if (debugfs_log->str == NULL)
+ return -1;
+
+ spin_lock(&data->log_lock);
+
+ va_start(args, fmt);
+ len = vsnprintf(data->log_work_buff, sizeof(data->log_work_buff), fmt,
+ args);
+ va_end(args);
+
+ if (len >= sizeof(data->log_work_buff)) {
+ #define truncate_msg "The next message has been truncated.\n"
+ copy_msg_to_log(data, truncate_msg, sizeof(truncate_msg));
+ }
+
+ len = copy_msg_to_log(data, data->log_work_buff, len);
+ spin_unlock(&data->log_lock);
+
+ return len;
+}
+
+/* initialize a log corresponding to a btrfs volume */
+static int debugfs_log_init(struct debugfs_vol_data *data)
+{
+ int err = 0;
+ struct lstring *debugfs_log = data->debugfs_log;
+
+ spin_lock(&data->log_lock);
+ debugfs_log->str = vmalloc(INIT_LOG_ALLOC_SIZE);
+
+ if (debugfs_log->str) {
+ memset(debugfs_log->str, 0, INIT_LOG_ALLOC_SIZE);
+ data->log_alloc_size = INIT_LOG_ALLOC_SIZE;
+ } else {
+ err = -ENOMEM;
+ }
+
+ spin_unlock(&data->log_lock);
+ return err;
+}
+
+/* free a log corresponding to a btrfs volume */
+static void debugfs_log_exit(struct debugfs_vol_data *data)
+{
+ struct lstring *debugfs_log = data->debugfs_log;
+ spin_lock(&data->log_lock);
+ vfree(debugfs_log->str);
+ debugfs_log->str = NULL;
+ debugfs_log->len = 0;
+ spin_unlock(&data->log_lock);
+}
+
+/* fops to override for printing range data */
+static const struct file_operations btrfs_debugfs_range_fops = {
+ .read = __btrfs_debugfs_range_read,
+ .open = __btrfs_debugfs_open,
+};
+
+/* fops to override for printing inode data */
+static const struct file_operations btrfs_debugfs_inode_fops = {
+ .read = __btrfs_debugfs_inode_read,
+ .open = __btrfs_debugfs_open,
+};
+
+/* initialize debugfs for btrfs at module init */
+int btrfs_init_debugfs(void)
+{
+ debugfs_root_dentry = debugfs_create_dir(DEBUGFS_ROOT_NAME, NULL);
+ /*init list of debugfs data list */
+ INIT_LIST_HEAD(&debugfs_vol_data_list);
+ /*init lock to list of debugfs data list */
+ spin_lock_init(&data_list_lock);
+ if (!debugfs_root_dentry)
+ goto debugfs_error;
+ return 0;
+
+debugfs_error:
+ return -EIO;
+}
+
+/*
+ * on each volume mount, initialize the debugfs dentries and associated
+ * structures (debugfs_vol_data and debugfs_log)
+ */
+int btrfs_init_debugfs_volume(const char *uuid, struct super_block *sb)
+{
+ struct dentry *debugfs_volume_entry = NULL;
+ struct dentry *debugfs_range_entry = NULL;
+ struct dentry *debugfs_inode_entry = NULL;
+ struct debugfs_vol_data *range_data = NULL;
+ struct debugfs_vol_data *inode_data = NULL;
+ size_t dev_name_length = strlen(uuid);
+ char dev[NAME_MAX];
+
+ if (!debugfs_root_dentry)
+ goto debugfs_error;
+
+ /* create debugfs folder for this volume by mounted dev name */
+ memcpy(dev, uuid + DEV_NAME_CHOP, dev_name_length -
+ DEV_NAME_CHOP + 1);
+ debugfs_volume_entry = debugfs_create_dir(dev, debugfs_root_dentry);
+
+ if (!debugfs_volume_entry)
+ goto debugfs_error;
+
+ /* malloc and initialize debugfs_vol_data for range_data */
+ range_data = kmalloc(sizeof(struct debugfs_vol_data),
+ GFP_KERNEL | GFP_NOFS);
+ memset(range_data, 0, sizeof(struct debugfs_vol_data));
+ range_data->debugfs_log = NULL;
+ range_data->sb = sb;
+ spin_lock_init(&range_data->log_lock);
+ range_data->log_alloc_size = 0;
+
+ /* malloc and initialize debugfs_vol_data for range_data */
+ inode_data = kmalloc(sizeof(struct debugfs_vol_data),
+ GFP_KERNEL | GFP_NOFS);
+ memset(inode_data, 0, sizeof(struct debugfs_vol_data));
+ inode_data->debugfs_log = NULL;
+ inode_data->sb = sb;
+ spin_lock_init(&inode_data->log_lock);
+ inode_data->log_alloc_size = 0;
+
+ /*
+ * add debugfs_vol_data for inode data and range data for
+ * volume to list
+ */
+ range_data->de = debugfs_volume_entry;
+ inode_data->de = debugfs_volume_entry;
+ spin_lock(&data_list_lock);
+ list_add(&range_data->node, &debugfs_vol_data_list);
+ list_add(&inode_data->node, &debugfs_vol_data_list);
+ spin_unlock(&data_list_lock);
+
+ /* create debugfs range_data file */
+ debugfs_range_entry = debugfs_create_file("range_data",
+ S_IFREG | S_IRUSR | S_IWUSR |
+ S_IRUGO,
+ debugfs_volume_entry,
+ (void *) range_data,
+ &btrfs_debugfs_range_fops);
+ if (!debugfs_range_entry)
+ goto debugfs_error;
+
+ /* create debugfs inode_data file */
+ debugfs_inode_entry = debugfs_create_file("inode_data",
+ S_IFREG | S_IRUSR | S_IWUSR |
+ S_IRUGO,
+ debugfs_volume_entry,
+ (void *) inode_data,
+ &btrfs_debugfs_inode_fops);
+
+ if (!debugfs_inode_entry)
+ goto debugfs_error;
+
+ return 0;
+
+debugfs_error:
+
+ kfree(range_data);
+ kfree(inode_data);
+
+ return -EIO;
+}
+
+/*
+ * find volume mounted (match by superblock) and remove
+ * debugfs dentry
+ */
+void btrfs_exit_debugfs_volume(struct super_block *sb)
+{
+ struct list_head *head;
+ struct list_head *pos;
+ struct debugfs_vol_data *data;
+ spin_lock(&data_list_lock);
+ head = &debugfs_vol_data_list;
+
+ /* must clean up memory assicatied with superblock */
+ list_for_each(pos, head)
+ {
+ data = list_entry(pos, struct debugfs_vol_data, node);
+ if (data->sb == sb) {
+ list_del(pos);
+ debugfs_remove_recursive(data->de);
+ kfree(data);
+ data = NULL;
+ break;
+ }
+ }
+
+ spin_unlock(&data_list_lock);
+}
+
+/* clean up memory and remove dentries for debugsfs */
+void btrfs_exit_debugfs(void)
+{
+ /* first iterate through debugfs_vol_data_list and free memory */
+ struct list_head *head;
+ struct list_head *pos;
+ struct list_head *cur;
+ struct debugfs_vol_data *data;
+
+ spin_lock(&data_list_lock);
+ head = &debugfs_vol_data_list;
+ list_for_each_safe(pos, cur, head) {
+ data = list_entry(pos, struct debugfs_vol_data, node);
+ if (data && pos != head)
+ kfree(data);
+ }
+ spin_unlock(&data_list_lock);
+
+ /* remove all debugfs entries recursively from the root */
+ debugfs_remove_recursive(debugfs_root_dentry);
+}
+
+/* debugfs open file override from fops table */
+static int __btrfs_debugfs_open(struct inode *inode, struct file *file)
+{
+ if (inode->i_private)
+ file->private_data = inode->i_private;
+
+ return 0;
+}
+
+/* debugfs read file override from fops table */
+static ssize_t __btrfs_debugfs_range_read(struct file *file, char __user *user,
+ size_t count, loff_t *ppos)
+{
+ int err = 0;
+ struct super_block *sb;
+ struct btrfs_root *root;
+ struct btrfs_root *fs_root;
+ struct hot_inode_item *current_hot_inode;
+ struct debugfs_vol_data *data;
+ struct lstring *debugfs_log;
+ unsigned long inode_num;
+
+ data = (struct debugfs_vol_data *) file->private_data;
+ sb = data->sb;
+ root = btrfs_sb(sb);
+ fs_root = (struct btrfs_root *) root->fs_info->fs_root;
+
+ if (!data->debugfs_log) {
+ /* initialize debugfs log corresponding to this volume*/
+ debugfs_log = kmalloc(sizeof(struct lstring),
+ GFP_KERNEL | GFP_NOFS);
+ debugfs_log->str = NULL,
+ debugfs_log->len = 0;
+ data->debugfs_log = debugfs_log;
+ debugfs_log_init(data);
+ }
+
+ if ((unsigned long) *ppos > 0) {
+ /* caller is continuing a previous read, don't walk tree */
+ if ((unsigned long) *ppos >= data->debugfs_log->len)
+ goto clean_up;
+
+ goto print_to_user;
+ }
+
+ /* walk the inode tree */
+ current_hot_inode = find_next_hot_inode(fs_root, 0);
+
+ while (current_hot_inode) {
+ /* walk ranges, print data to debugfs log */
+ __walk_range_tree(current_hot_inode, data, fs_root);
+ inode_num = current_hot_inode->i_ino;
+ free_hot_inode_item(current_hot_inode);
+ current_hot_inode = find_next_hot_inode(fs_root, inode_num+1);
+ }
+
+print_to_user:
+ if (data->debugfs_log->len) {
+ err = simple_read_from_buffer(user, count, ppos,
+ data->debugfs_log->str,
+ data->debugfs_log->len);
+ }
+
+ return err;
+
+clean_up:
+ /* Reader has finished the file, clean up */
+
+ debugfs_log_exit(data);
+ kfree(data->debugfs_log);
+ data->debugfs_log = NULL;
+
+ return 0;
+}
+
+/* debugfs read file override from fops table */
+static ssize_t __btrfs_debugfs_inode_read(struct file *file, char __user *user,
+ size_t count, loff_t *ppos)
+{
+ int err = 0;
+ struct super_block *sb;
+ struct btrfs_root *root;
+ struct btrfs_root *fs_root;
+ struct hot_inode_item *current_hot_inode;
+ struct debugfs_vol_data *data;
+ struct lstring *debugfs_log;
+ unsigned long inode_num;
+
+ data = (struct debugfs_vol_data *) file->private_data;
+ sb = data->sb;
+ root = btrfs_sb(sb);
+ fs_root = (struct btrfs_root *) root->fs_info->fs_root;
+
+ if (!data->debugfs_log) {
+ /* initialize debugfs log corresponding to this volume */
+ debugfs_log = kmalloc(sizeof(struct lstring),
+ GFP_KERNEL | GFP_NOFS);
+ debugfs_log->str = NULL,
+ debugfs_log->len = 0;
+ data->debugfs_log = debugfs_log;
+ debugfs_log_init(data);
+ }
+
+ if ((unsigned long) *ppos > 0) {
+ /* caller is continuing a previous read, don't walk tree */
+ if ((unsigned long) *ppos >= data->debugfs_log->len)
+ goto clean_up;
+
+ goto print_to_user;
+ }
+
+ /* walk the inode tree */
+ current_hot_inode = find_next_hot_inode(fs_root, 0);
+
+ while (current_hot_inode) {
+ /* walk ranges, print data to debugfs log */
+ __print_inode_freq_data(current_hot_inode, data, fs_root);
+ inode_num = current_hot_inode->i_ino;
+ free_hot_inode_item(current_hot_inode);
+ current_hot_inode = find_next_hot_inode(fs_root, inode_num+1);
+ }
+
+print_to_user:
+ if (data->debugfs_log->len) {
+ err = simple_read_from_buffer(user, count, ppos,
+ data->debugfs_log->str,
+ data->debugfs_log->len);
+ }
+
+ return err;
+
+clean_up:
+ /* reader has finished the file, clean up */
+ debugfs_log_exit(data);
+ kfree(data->debugfs_log);
+ data->debugfs_log = NULL;
+
+ return 0;
+}
+
+/*
+ * take the inode, find ranges associated with inode
+ * and print each range data struct
+ */
+static void __walk_range_tree(struct hot_inode_item *hot_inode,
+ struct debugfs_vol_data *data,
+ struct btrfs_root *fs_root)
+{
+ struct hot_range_tree *inode_range_tree;
+ struct rb_node *node;
+ struct hot_range_item *current_range;
+
+ inode_range_tree = &hot_inode->hot_range_tree;
+ read_lock(&inode_range_tree->lock);
+ node = rb_first(&inode_range_tree->map);
+
+ /* Walk the hot_range_tree for inode */
+ while (node) {
+ current_range = rb_entry(node, struct hot_range_item, rb_node);
+ __print_range_freq_data(hot_inode, current_range, data,
+ fs_root);
+ node = rb_next(node);
+ }
+ read_unlock(&inode_range_tree->lock);
+}
+
+/* Print frequency data for each range to log */
+static void __print_range_freq_data(struct hot_inode_item *hot_inode,
+ struct hot_range_item *hot_range,
+ struct debugfs_vol_data *data,
+ struct btrfs_root *fs_root)
+{
+ struct btrfs_freq_data *freq_data;
+ u64 start;
+ u64 len;
+ int on_rotating;
+
+ freq_data = &hot_range->freq_data;
+
+ spin_lock(&hot_range->lock);
+ start = hot_range->start;
+ len = hot_range->len;
+ spin_unlock(&hot_range->lock);
+
+ on_rotating = btrfs_range_on_rotating(fs_root, hot_inode, start,
+ len);
+ /* Always lock hot_inode_item first */
+ spin_lock(&hot_inode->lock);
+ spin_lock(&hot_range->lock);
+ debugfs_log(data, "inode #%lu, range start "
+ "%llu (range len %llu) reads %u, writes %u, "
+ "avg read time %llu, avg write time %llu, temp %u, "
+ "on_rotating %d\n",
+ hot_inode->i_ino,
+ hot_range->start,
+ hot_range->len,
+ freq_data->nr_reads,
+ freq_data->nr_writes,
+ freq_data->avg_delta_reads,
+ freq_data->avg_delta_writes,
+ freq_data->last_temp,
+ on_rotating);
+ spin_unlock(&hot_range->lock);
+ spin_unlock(&hot_inode->lock);
+}
+
+/* Print frequency data for each freq data to log */
+static void __print_inode_freq_data(struct hot_inode_item *hot_inode,
+ struct debugfs_vol_data *data,
+ struct btrfs_root *fs_root)
+{
+ struct btrfs_freq_data *freq_data = &hot_inode->freq_data;
+ int on_rotating = btrfs_range_on_rotating(fs_root, hot_inode, 0,
+ (u64)-1);
+
+ spin_lock(&hot_inode->lock);
+ debugfs_log(data, "inode #%lu, reads %u, writes %u, "
+ "avg read time %llu, avg write time %llu, temp %u, "
+ "on_rotating %d\n",
+ hot_inode->i_ino,
+ freq_data->nr_reads,
+ freq_data->nr_writes,
+ freq_data->avg_delta_reads,
+ freq_data->avg_delta_writes,
+ freq_data->last_temp,
+ on_rotating);
+ spin_unlock(&hot_inode->lock);
+}
diff --git a/fs/btrfs/debugfs.h b/fs/btrfs/debugfs.h
new file mode 100644
index 0000000..492ff8f
--- /dev/null
+++ b/fs/btrfs/debugfs.h
@@ -0,0 +1,89 @@
+/*
+ * fs/btrfs/debugfs.h
+ *
+ * Copyright (C) 2010 International Business Machines Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __BTRFS_DEBUGFS__
+#define __BTRFS_DEBUGFS__
+
+/* size of log to vmalloc */
+#define INIT_LOG_ALLOC_SIZE (PAGE_SIZE * 10)
+#define LOG_PAGE_SIZE (PAGE_SIZE * 10)
+
+/*
+ * number of chars of device name of chop off for making debugfs folder
+ * e.g. /dev/sda -> sda
+ *
+ * TODO: use something better for this
+ */
+#define DEV_NAME_CHOP 5
+
+/* list to keep track of each mounted volumes debugfs_vol_data */
+static struct list_head debugfs_vol_data_list;
+
+/* lock for debugfs_vol_data_list */
+static spinlock_t data_list_lock;
+
+/*
+ * Name for BTRFS data in debugfs directory
+ * e.g. /sys/kernel/debug/btrfs_data
+ */
+#define DEBUGFS_ROOT_NAME "btrfs_data"
+
+/* pointer to top level debugfs dentry */
+static struct dentry *debugfs_root_dentry;
+
+/* log to output to userspace in debugfs files */
+struct lstring {
+ char *str;
+ unsigned long len;
+};
+
+/* debugfs_vol_data is a struct of items that is passed to the debugfs */
+struct debugfs_vol_data {
+ struct list_head node; /* protected by data_list_lock */
+ struct lstring *debugfs_log;
+ struct super_block *sb;
+ struct dentry *de;
+ spinlock_t log_lock; /* protects debugfs_log */
+ char log_work_buff[1024];
+ uint log_alloc_size;
+};
+
+static ssize_t __btrfs_debugfs_range_read(struct file *file, char __user *user,
+ size_t size, loff_t *len);
+
+static ssize_t __btrfs_debugfs_inode_read(struct file *file, char __user *user,
+ size_t size, loff_t *len);
+
+static int __btrfs_debugfs_open(struct inode *inode, struct file *file);
+
+static void __walk_range_tree(struct hot_inode_item *hot_inode,
+ struct debugfs_vol_data *data,
+ struct btrfs_root *root);
+
+static void __print_range_freq_data(struct hot_inode_item *hot_inode,
+ struct hot_range_item *hot_range,
+ struct debugfs_vol_data *data,
+ struct btrfs_root *root);
+
+static void __print_inode_freq_data(struct hot_inode_item *hot_inode,
+ struct debugfs_vol_data *data,
+ struct btrfs_root *root);
+
+#endif
--
1.7.1

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Prev: [GIT PULL] ocfs2 changes for 2.6.36, part 1.
Next: [RFC] reworked NX protection for kernel data