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SubjectRe: [2.6.16 PATCH] Filesystem Events Reporter v1
Evgeniy Polyakov wrote:
> On Mon, Apr 03, 2006 at 10:28:10PM +0800, Yi Yang (yang.y.yi@gmail.com) wrote:
>
>> This patch has some very big changes with comparison to Filesystem Events Connector v4,
>> the following features are added newly:
>>
>> - Use netlink instead of connector.
>> - Every application using fsevent can set its own fsevent filter list
>> without effect in other applications using fsevent, there are three
>> filter lists, they are pid filter list, uid filetr list and gid
>> filter list, respectively, moreover, there is a fsevent mask used to
>> control those fsevents which fail to match three filter lists, an
>> application using fsevent can listen those fsevents it want to
>> monitor and ignore those fsevents it doesn't interest in by set
>> series of filters, there is a fsevent mask used to take effects on
>> all the applications using fsevent, it can be set by sysctl and proc
>> interface(not implemented).
>> - Remove lock race overhead and file system code path delay completely
>> by a per cpu fsevent queue and kthread per cpu, fsevent_send just
>> mallocs a skb and insert the percpu queue and wake up fseventd
>> kthread, then return immediately, fseventd per cpu is responsible for
>> send fsevent to userspace application.
>>
>
> Just FYI, this step has been already implemented in CBUS - connector based message bus.
>
>
>> fs/Kconfig | 10
>> fs/Makefile | 1
>> fs/fsevent.c | 642 ++++++++++++++++++++++++++++++++++++++++++++++
>> fs/namespace.c | 12
>> include/linux/fsevent.h | 132 +++++++++
>> include/linux/fsnotify.h | 37 ++
>> include/linux/netlink.h | 3
>> 7 files changed, 836 insertions(+), 1 deletion(-)
>>
>> Signed-off-by: Yi Yang <yang.y.yi@gmail.com>
>>
>> --- a/include/linux/netlink.h.orig 2006-03-31 22:58:50.000000000 +0800
>> +++ b/include/linux/netlink.h 2006-03-31 23:00:22.000000000 +0800
>> @@ -20,7 +20,8 @@
>> #define NETLINK_IP6_FW 13
>> #define NETLINK_DNRTMSG 14 /* DECnet routing messages */
>> #define NETLINK_KOBJECT_UEVENT 15 /* Kernel messages to userspace */
>> -#define NETLINK_GENERIC 16
>> +#define NETLINK_FSEVENT 16 /* File system events to userspace */
>> +#define NETLINK_GENERIC 17
>>
>
> You are not allowed to change other numbers, just add your own new number.
>
>
>> #define MAX_LINKS 32
>>
>> --- a/include/linux/fsnotify.h.orig 2006-01-03 11:21:10.000000000 +0800
>> +++ b/include/linux/fsnotify.h 2006-03-27 23:09:18.000000000 +0800
>> @@ -15,6 +15,7 @@
>>
>> #include <linux/dnotify.h>
>> #include <linux/inotify.h>
>> +#include <linux/fsevent.h>
>>
>> /*
>> * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
>> @@ -45,6 +46,8 @@ static inline void fsnotify_move(struct
>> if (source) {
>> inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL);
>> }
>> + raise_fsevent_move(old_dir, old_name, new_dir, new_name,
>> + FSEVENT_MOVE | (isdir?FSEVENT_ISDIR:0));
>> }
>>
>> /*
>> @@ -56,6 +59,8 @@ static inline void fsnotify_nameremove(s
>> isdir = IN_ISDIR;
>> dnotify_parent(dentry, DN_DELETE);
>> inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name);
>> + raise_fsevent(dentry,
>> + FSEVENT_DELETE | (isdir?FSEVENT_ISDIR:0));
>> }
>>
>> /*
>> @@ -74,6 +79,7 @@ static inline void fsnotify_create(struc
>> {
>> inode_dir_notify(inode, DN_CREATE);
>> inotify_inode_queue_event(inode, IN_CREATE, 0, name);
>> + raise_fsevent_create(inode, name, FSEVENT_CREATE);
>> }
>>
>> /*
>> @@ -83,6 +89,8 @@ static inline void fsnotify_mkdir(struct
>> {
>> inode_dir_notify(inode, DN_CREATE);
>> inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, name);
>> + raise_fsevent_create(inode, name,
>> + FSEVENT_CREATE | FSEVENT_ISDIR);
>> }
>>
>> /*
>> @@ -99,6 +107,8 @@ static inline void fsnotify_access(struc
>> dnotify_parent(dentry, DN_ACCESS);
>> inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
>> inotify_inode_queue_event(inode, mask, 0, NULL);
>> + raise_fsevent(dentry, FSEVENT_ACCESS |
>> + ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
>> }
>>
>> /*
>> @@ -115,6 +125,8 @@ static inline void fsnotify_modify(struc
>> dnotify_parent(dentry, DN_MODIFY);
>> inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
>> inotify_inode_queue_event(inode, mask, 0, NULL);
>> + raise_fsevent(dentry, FSEVENT_MODIFY |
>> + ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
>> }
>>
>> /*
>> @@ -130,6 +142,9 @@ static inline void fsnotify_open(struct
>>
>> inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
>> inotify_inode_queue_event(inode, mask, 0, NULL);
>> + raise_fsevent(dentry, FSEVENT_OPEN |
>> + ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
>> +
>> }
>>
>> /*
>> @@ -148,6 +163,8 @@ static inline void fsnotify_close(struct
>>
>> inotify_dentry_parent_queue_event(dentry, mask, 0, name);
>> inotify_inode_queue_event(inode, mask, 0, NULL);
>> + raise_fsevent(dentry, FSEVENT_CLOSE |
>> + ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
>> }
>>
>> /*
>> @@ -163,6 +180,8 @@ static inline void fsnotify_xattr(struct
>>
>> inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
>> inotify_inode_queue_event(inode, mask, 0, NULL);
>> + raise_fsevent(dentry, FSEVENT_MODIFY_ATTRIB |
>> + ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
>> }
>>
>> /*
>> @@ -213,6 +232,24 @@ static inline void fsnotify_change(struc
>> inotify_dentry_parent_queue_event(dentry, in_mask, 0,
>> dentry->d_name.name);
>> }
>> +
>> +#ifdef CONFIG_FS_EVENTS
>> + {
>> + u32 fsevent_mask = 0;
>> + if (ia_valid & (ATTR_UID | ATTR_GID | ATTR_MODE))
>> + fsevent_mask |= FSEVENT_MODIFY_ATTRIB;
>> + if ((ia_valid & ATTR_ATIME) && (ia_valid & ATTR_MTIME))
>> + fsevent_mask |= FSEVENT_MODIFY_ATTRIB;
>> + else if (ia_valid & ATTR_ATIME)
>> + fsevent_mask |= FSEVENT_ACCESS;
>> + else if (ia_valid & ATTR_MTIME)
>> + fsevent_mask |= FSEVENT_MODIFY;
>> + if (ia_valid & ATTR_SIZE)
>> + fsevent_mask |= FSEVENT_MODIFY;
>> + if (fsevent_mask)
>> + raise_fsevent(dentry, fsevent_mask);
>> + }
>> +#endif /* CONFIG_FS_EVENTS */
>> }
>>
>> #ifdef CONFIG_INOTIFY /* inotify helpers */
>> --- a/fs/namespace.c.orig 2006-03-25 23:13:42.000000000 +0800
>> +++ b/fs/namespace.c 2006-03-27 23:09:18.000000000 +0800
>> @@ -25,6 +25,7 @@
>> #include <linux/mount.h>
>> #include <asm/uaccess.h>
>> #include <asm/unistd.h>
>> +#include <linux/fsevent.h>
>> #include "pnode.h"
>>
>> extern int __init init_rootfs(void);
>> @@ -612,6 +613,13 @@ asmlinkage long sys_umount(char __user *
>> goto dput_and_out;
>>
>> retval = do_umount(nd.mnt, flags);
>> +
>> + if (retval == 0) {
>> + char * tmp = getname(name);
>> + raise_fsevent_umount(tmp);
>> + putname(tmp);
>> + }
>> +
>> dput_and_out:
>> path_release_on_umount(&nd);
>> out:
>> @@ -1459,6 +1467,10 @@ asmlinkage long sys_mount(char __user *
>> retval = do_mount((char *)dev_page, dir_page, (char *)type_page,
>> flags, (void *)data_page);
>> unlock_kernel();
>> +
>> + if (retval == 0)
>> + raise_fsevent_mount((char *)dev_page, dir_page);
>> +
>> free_page(data_page);
>>
>> out3:
>> --- a/fs/Kconfig.orig 2006-03-31 21:23:20.000000000 +0800
>> +++ b/fs/Kconfig 2006-04-03 22:01:17.000000000 +0800
>> @@ -405,6 +405,16 @@ config INOTIFY
>>
>> If unsure, say Y.
>>
>> +config FS_EVENTS
>> + tristate "Report filesystem events to userspace"
>> + ---help---
>> + Provide a facility that reports filesystem events to userspace. The
>> + reported event include access, write, utime, chmod, chown, chgrp,
>> + close, open, create, rename, unlink, mkdir, rmdir, mount, umount.
>> +
>> + The user can set filesystem events filter to filter its events, so
>> + that he just get those events he concerns.
>> +
>> config QUOTA
>> bool "Quota support"
>> help
>> --- a/fs/Makefile.orig 2006-03-31 21:23:33.000000000 +0800
>> +++ b/fs/Makefile 2006-03-31 21:30:58.000000000 +0800
>> @@ -13,6 +13,7 @@ obj-y := open.o read_write.o file_table.
>> ioprio.o pnode.o drop_caches.o
>>
>> obj-$(CONFIG_INOTIFY) += inotify.o
>> +obj-$(CONFIG_FS_EVENTS) += fsevent.o
>> obj-$(CONFIG_EPOLL) += eventpoll.o
>> obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o
>>
>> --- /dev/null 2003-01-30 18:24:37.000000000 +0800
>> +++ b/include/linux/fsevent.h 2006-04-02 01:35:04.000000000 +0800
>> @@ -0,0 +1,132 @@
>> +/*
>> + * fsevent.h - filesystem events connector
>> + *
>> + * Copyright (C) 2006 Yi Yang <yang.y.yi@gmail.com>
>> + * Based on cn_proc.h by Matt Helsley, IBM Corp
>> + *
>> + * This program 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 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * 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 02111-1307 USA
>> + */
>> +
>> +#ifndef LINUX_FSEVENT_H
>> +#define LINUX_FSEVENT_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/time.h>
>> +#include <linux/netlink.h>
>> +
>> +enum fsevent_type {
>> + FSEVENT_ACCESS = 0x00000001, /* File was accessed */
>> + FSEVENT_MODIFY = 0x00000002, /* File was modified */
>> + FSEVENT_MODIFY_ATTRIB = 0x00000004, /* Metadata changed */
>> + FSEVENT_CLOSE = 0x00000008, /* File was closed */
>> + FSEVENT_OPEN = 0x00000010, /* File was opened */
>> + FSEVENT_MOVE = 0x00000020, /* File was moved */
>> + FSEVENT_CREATE = 0x00000040, /* File was created */
>> + FSEVENT_DELETE = 0x00000080, /* File was deleted */
>> + FSEVENT_MOUNT = 0x00000100, /* File system is mounted */
>> + FSEVENT_UMOUNT = 0x00000200, /* File system is umounted */
>> +
>> + /* The following definitions are commands for event filter
>> + * , in acknowlege event for the corresponding command, it
>> + * will set to type field of struct fsevent.
>> + */
>> + FSEVENT_FILTER_ALL = 0x08000000, /* For all events */
>> + FSEVENT_FILTER_PID = 0x10000000, /* For some process ID */
>> + FSEVENT_FILTER_UID = 0x20000000, /* For some user ID */
>> + FSEVENT_FILTER_GID = 0x40000000, /* For some group ID */
>> +
>> + FSEVENT_ISDIR = 0x80000000 /* It is set for a dir */
>> +};
>> +
>> +#define FSEVENT_MASK 0x800003ff
>> +
>> +typedef unsigned long fsevent_mask_t;
>> +
>> +enum filter_control {
>> + FSEVENT_FILTER_LISTEN = 1, /* Listen fsevents mask defines*/
>> + FSEVENT_FILTER_IGNORE , /* Ignore fsevents mask defines*/
>> + FSEVENT_FILTER_REMOVE, /* Remove a given filter */
>> +};
>> +
>> +struct fsevent_filter {
>> + /* filter type, it just is one or bit-or of them
>> + * FSEVENT_FILTER_ALL
>> + * FSEVENT_FILTER_PID
>> + * FSEVENT_FILTER_UID
>> + * FSEVENT_FILTER_GID
>> + */
>> + enum fsevent_type type; /* filter type */
>> +
>> + /* mask of file system events the user listen or ignore
>> + * if the user need to ignore all the events of some pid
>> + * , gid or uid, he(she) must set mask to FSEVENT_MASK.
>> + */
>> + fsevent_mask_t mask;
>> + union {
>> + pid_t pid;
>> + uid_t uid;
>> + gid_t gid;
>> + } id;
>> +
>> + enum filter_control control;
>> +};
>> +
>> +struct fsevent {
>> + __u32 type;
>> + __u32 cpu;
>> + struct timespec timestamp;
>> + pid_t pid;
>> + uid_t uid;
>> + gid_t gid;
>> + int err;
>> + __u32 len;
>> + __u32 pname_len;
>> + __u32 fname_len;
>> + __u32 new_fname_len;
>> + char name[0];
>> +};
>> +
>> +#define FSEVENT_FILTER_MSGSIZE \
>> + (sizeof(struct fsevent_filter) + sizeof(struct nlmsghdr))
>> +
>> +#ifdef __KERNEL__
>> +#ifdef CONFIG_FS_EVENTS
>> +extern void raise_fsevent(struct dentry * dentryp, u32 mask);
>> +extern void raise_fsevent_move(struct inode * olddir, const char * oldname,
>> + struct inode * newdir, const char * newname, u32 mask);
>> +extern void raise_fsevent_create(struct inode * inode,
>> + const char * name, u32 mask);
>> +extern void raise_fsevent_mount(const char * devname, const char * mountpoint);
>> +extern void raise_fsevent_umount(const char * mountpoint);
>> +#else
>> +static void raise_fsevent(struct dentry * dentryp, u32 mask)
>> +{}
>> +
>> +static void raise_fsevent_move(struct inode * olddir, const char * oldname,
>> + struct inode * newdir, const char * newname, u32 mask)
>> +{}
>> +
>> +static void raise_fsevent_create(struct inode * inode,
>> + const char * name, u32 mask)
>> +{}
>> +
>> +static void raise_fsevent_mount(const char * devname, const char * mountpoint)
>> +{}
>> +
>> +static void raise_fsevent_umount(const char * mountpoint)
>> +{}
>> +#endif /* CONFIG_FS_EVENTS */
>> +#endif /* __KERNEL__ */
>> +#endif /* LINUX_FSEVENT_H */
>> --- /dev/null 2003-01-30 18:24:37.000000000 +0800
>> +++ b/fs/fsevent.c 2006-04-02 23:10:45.000000000 +0800
>> @@ -0,0 +1,642 @@
>> +/*
>> + * fsevent.c
>> + *
>> + * 2006 Copyright (c) Yi Yang <yang.y.yi@gmail.com>
>> + * All rights reserved.
>> + *
>> + * This program 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 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * 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 02111-1307 USA
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/skbuff.h>
>> +#include <linux/netlink.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/fsevent.h>
>> +#include <linux/skbuff.h>
>> +#include <net/sock.h>
>> +#include <linux/list.h>
>> +#include <linux/percpu.h>
>> +#include <linux/cpu.h>
>> +#include <linux/kthread.h>
>> +#include <linux/notifier.h>
>> +#include <linux/compiler.h>
>> +
>> +static DEFINE_PER_CPU(struct sk_buff_head, fsevent_send_queue);
>> +static DEFINE_PER_CPU(task_t *, kfseventd_task);
>> +
>> +typedef struct pid_filter {
>> + pid_t pid;
>> + u32 mask;
>> + struct list_head list;
>> +} pid_filter;
>> +
>> +typedef struct uid_filter {
>> + uid_t uid;
>> + u32 mask;
>> + struct list_head list;
>> +} uid_filter;
>> +
>> +typedef struct gid_filter {
>> + gid_t gid;
>> + u32 mask;
>> + struct list_head list;
>> +} gid_filter;
>> +
>> +typedef struct fsevent_listener {
>> + pid_t pid;
>> + struct list_head pid_filter_list_head;
>> + struct list_head uid_filter_list_head;
>> + struct list_head gid_filter_list_head;
>> + u32 mask;
>> + struct list_head list;
>> +} listener;
>> +
>> +
>> +/* The netlink socket. */
>> +static struct sock * fsevent_sock = NULL;
>> +static LIST_HEAD(listener_list_head);
>> +static DEFINE_SPINLOCK(listener_list_lock);
>> +
>> +static DEFINE_PER_CPU(__u32, cn_fs_event_counts) = { 0 };
>> +static int fsevent_burst_limit = 100;
>> +static int fsevent_ratelimit = 5 * HZ;
>> +static unsigned long last = 0;
>> +static int fsevent_sum = 0;
>> +static u32 fsevents_mask = FSEVENT_MASK;
>> +static atomic_t fsevent_listener_num = ATOMIC_INIT(0);
>> +
>> +static inline void get_seq(__u32 *ts, int *cpu)
>> +{
>> + *ts = get_cpu_var(cn_fs_event_counts)++;
>> + *cpu = smp_processor_id();
>> + put_cpu_var(cn_fs_event_counts);
>> +}
>>
>
> This is not enough, sequence number must be uniq for the whole system,
> not only one processor.
>
>
I'll convert it to atomic_t type.
>> +
>> +static void append_string(char **dest, const char *src, size_t len)
>> +{
>> + strncpy(*dest, src, len);
>> + (*dest)[len] = '\0';
>> + *dest += len + 1;
>> +}
>> +
>> +static inline int filter_fsevent(u32 filter_mask, u32 event_mask)
>> +{
>> + event_mask &= FSEVENT_MASK;
>> + event_mask &= filter_mask;
>> + if (event_mask == 0) {
>> + return -1;
>> + }
>> + return 0;
>> +}
>> +
>> +static int filter_fsevent_all(u32 * mask)
>> +{
>> + int ret = 0;
>> +
>> + (*mask) &= FSEVENT_MASK;
>> +
>> + if ((((*mask) & FSEVENT_ISDIR) == FSEVENT_ISDIR)
>> + && ((fsevents_mask & FSEVENT_ISDIR) == 0)) {
>> + ret = -1;
>> + goto out;
>> + }
>> +
>> + (*mask) &= fsevents_mask;
>> + if ((*mask) == 0) {
>> + ret = -5;
>> + }
>> +
>> +out:
>> + return ret;
>> +}
>> +
>> +static void fsevent_send(struct sk_buff * skb)
>> +{
>> + struct sk_buff_head * head = &get_cpu_var(fsevent_send_queue);
>> + skb_queue_tail(head, skb);
>> + wake_up_process(per_cpu(kfseventd_task, smp_processor_id()));
>> + put_cpu_var(fsevent_send_queue);
>> +}
>> +
>>
>
> This will heavily reorder messages, hope you have sequence number for
> them?
>
I think the order of fsevents should doesn't matter, as you said, it is
more appropriate to add a sequence
number into struct fsevent, let applications consider it.
>
>> +int __raise_fsevent(const char * oldname, const char * newname, u32 mask)
>> +{
>> + struct fsevent *event;
>> + int namelen = 0;
>> + char * nameptr = NULL;
>> + unsigned int size;
>> + struct nlmsghdr * nlhdr;
>> + struct sk_buff * skb = NULL;
>> +
>> + if (filter_fsevent_all(&mask) != 0)
>> + return -1;
>> +
>> + if (atomic_read(&fsevent_listener_num) <= 0)
>> + return -1;
>> +
>> + if (jiffies - last <= fsevent_ratelimit) {
>> + if (fsevent_sum > fsevent_burst_limit)
>> + return -2;
>> + fsevent_sum++;
>> + } else {
>> + last = jiffies;
>> + fsevent_sum = 0;
>> + }
>> +
>> + namelen = strlen(current->comm) + strlen(oldname) + 2;
>> + if (newname)
>> + namelen += strlen(newname) + 1;
>> +
>> + size = NLMSG_SPACE(sizeof(struct fsevent) + namelen);
>> +
>> + skb = alloc_skb(size, GFP_KERNEL);
>> + if (!skb)
>> + return -ENOMEM;
>> +
>> + nlhdr = NLMSG_PUT(skb, 0, 0, NLMSG_DONE, size - sizeof(*nlhdr));
>> + event = NLMSG_DATA(nlhdr);
>> +
>> + get_seq(&(nlhdr->nlmsg_seq), &event->cpu);
>> + ktime_get_ts(&event->timestamp);
>>
>
> Using timestamp is a good idea.
>
>
>> + event->type = mask;
>> + event->pid = current->tgid;
>> + event->uid = current->uid;
>> + event->gid = current->gid;
>> + nameptr = event->name;
>> + event->pname_len = strlen(current->comm);
>> + append_string(&nameptr, current->comm, event->pname_len);
>> + event->fname_len = strlen(oldname);
>> + append_string(&nameptr, oldname, event->fname_len);
>> + event->len = event->pname_len + event->fname_len + 2;
>> + event->new_fname_len = 0;
>> + if (newname) {
>> + event->new_fname_len = strlen(newname);
>> + append_string(&nameptr, newname, event->new_fname_len);
>> + event->len += event->new_fname_len + 1;
>> + }
>> + fsevent_send(skb);
>> + return 0;
>> +
>> +nlmsg_failure:
>> + kfree_skb(skb);
>> + return -1;
>> +}
>> +
>> +void raise_fsevent(struct dentry * dentryp, u32 mask)
>> +{
>> + if (dentryp->d_inode && (MAJOR(dentryp->d_inode->i_rdev) == 4))
>>
>
> Why only tty is missed?
>
for console applications using fsevent, if they output fsevent messages
to the console, a unlimited tty
operation loop will happen, this will mask some important fsevents, so
I mask tty operations.
In fact, I think nobody concerns activities on ttys.
>
>> + return;
>> + __raise_fsevent(dentryp->d_name.name, NULL, mask);
>> +}
>> +EXPORT_SYMBOL_GPL(raise_fsevent);
>> +
>> +void raise_fsevent_create(struct inode * inode, const char * name, u32 mask)
>> +{
>> + __raise_fsevent(name, NULL, mask);
>> +}
>> +EXPORT_SYMBOL_GPL(raise_fsevent_create);
>> +
>> +void raise_fsevent_move(struct inode * olddir, const char * oldname,
>> + struct inode * newdir, const char * newname, u32 mask)
>> +{
>> + __raise_fsevent(oldname, newname, mask);
>> +}
>> +EXPORT_SYMBOL_GPL(raise_fsevent_move);
>> +
>> +void raise_fsevent_mount(const char * devname, const char * mountpoint)
>> +{
>> + __raise_fsevent(devname, mountpoint, FSEVENT_MOUNT);
>> +}
>> +
>> +void raise_fsevent_umount(const char * mountpoint)
>> +{
>> + __raise_fsevent(mountpoint, NULL, FSEVENT_UMOUNT);
>> +}
>> +
>> +static int fsevent_ack(enum fsevent_type type, pid_t pid, u32 seq)
>> +{
>> + struct fsevent *event;
>> + unsigned int size;
>> + struct sk_buff * skb = NULL;
>> + struct nlmsghdr * nlhdr = NULL;
>> +
>> + size = NLMSG_SPACE(sizeof(struct fsevent));
>> +
>> + skb = alloc_skb(size, GFP_KERNEL);
>> + if (!skb)
>> + return -ENOMEM;
>> +
>> + nlhdr = NLMSG_PUT(skb, 0, seq, NLMSG_DONE, size - sizeof(*nlhdr));
>> + event = NLMSG_DATA(nlhdr);
>> +
>> + ktime_get_ts(&event->timestamp);
>> + event->cpu = -1;
>> + event->type = type;
>> + event->pid = 0;
>> + event->uid = 0;
>> + event->gid = 0;
>> + event->len = 0;
>> + event->pname_len = 0;
>> + event->fname_len = 0;
>> + event->new_fname_len = 0;
>> + event->err = 0;
>> +
>> + NETLINK_CB(skb).dst_group = 0;
>> + NETLINK_CB(skb).dst_pid = pid;
>> + NETLINK_CB(skb).pid = 0;
>> +
>> + return (netlink_unicast(fsevent_sock, skb, pid, MSG_DONTWAIT));
>>
>
> Actually broadcasting is much more optimized that unicast for each
> user.
>
because fsevent ack is just for one specific process, so netlink_unicast
is only one option.
>
>> +nlmsg_failure:
>> + kfree_skb(skb);
>> + return -1;
>> +}
>> +
>> +static void set_fsevent_mask(u32 * to_mask, u32 from_mask, int mode)
>> +{
>> + if (mode == FSEVENT_FILTER_IGNORE)
>> + (*to_mask) &= ~(from_mask);
>> + else if (mode == FSEVENT_FILTER_LISTEN)
>> + (*to_mask) |= from_mask;
>> +}
>> +
>> +#define DEFINE_FILTER_FIND_FUNC(type, key) \
>> + type * find_##type(struct list_head * head, key##_t id) \
>> + { \
>> + int alloc_flag = 1; \
>> + type * entry = NULL; \
>> + \
>> + list_for_each_entry(entry, head, list) { \
>> + if (entry->key == id) { \
>> + alloc_flag = 0; \
>> + break; \
>> + } \
>> + } \
>> + \
>> + if (alloc_flag == 1) { \
>> + entry = (type *)kmalloc(sizeof(type), GFP_KERNEL); \
>> + if (entry == NULL) \
>> + return NULL; \
>> + memset(entry, 0, sizeof(type)); \
>> + entry->key = id; \
>> + list_add_tail(&(entry->list), head); \
>> + } \
>> + return entry; \
>> + } \
>> +
>> +DEFINE_FILTER_FIND_FUNC(pid_filter, pid)
>> +
>> +DEFINE_FILTER_FIND_FUNC(uid_filter, uid)
>> +
>> +DEFINE_FILTER_FIND_FUNC(gid_filter, gid)
>> +
>> +DEFINE_FILTER_FIND_FUNC(listener, pid)
>> +
>> +static void set_fsevent_filter(struct fsevent_filter * filter, pid_t pid)
>> +{
>> + enum fsevent_type type;
>> + u32 mask = 0;
>> + int control = 0;
>> + listener * listenerp = NULL;
>> + pid_filter * pfilter = NULL;
>> + uid_filter * ufilter = NULL;
>> + gid_filter * gfilter = NULL;
>> +
>> +
>> + mask = filter->mask;
>> + control = filter->control;
>> + type = filter->type;
>> + mask &= FSEVENT_MASK;
>> + if (mask == 0)
>> + goto out;
>> +
>> + spin_lock(&listener_list_lock);
>> + listenerp = find_listener(&listener_list_head, pid);
>> + if (unlikely(listenerp == NULL)) {
>> + spin_unlock(&listener_list_lock);
>> + return;
>> + }
>> +
>> + if (!(listenerp->pid_filter_list_head.next)) {
>> + INIT_LIST_HEAD(&(listenerp->pid_filter_list_head));
>> + INIT_LIST_HEAD(&(listenerp->uid_filter_list_head));
>> + INIT_LIST_HEAD(&(listenerp->gid_filter_list_head));
>> + }
>> + spin_unlock(&listener_list_lock);
>> +
>> + if ((type & FSEVENT_FILTER_ALL) == FSEVENT_FILTER_ALL) {
>> + if (control == FSEVENT_FILTER_REMOVE) {
>> + atomic_dec(&fsevent_listener_num);
>> + spin_lock(&listener_list_lock);
>> + list_del(&(listenerp->list));
>> + spin_unlock(&listener_list_lock);
>> + kfree(listenerp);
>> + } else
>> + set_fsevent_mask(&(listenerp->mask), mask, control);
>> + }
>> +
>> +
>> + if ((type & FSEVENT_FILTER_PID) == FSEVENT_FILTER_PID) {
>> + pfilter = find_pid_filter(&(listenerp->pid_filter_list_head),
>> + filter->id.pid);
>>
>
> What does prevent this lists to be changed in parallel?
> Defined above functions do not hold any lock.
>
Yes, I missed spinlock, I'll add it.
>
>> + if (unlikely(pfilter == NULL))
>> + return;
>> +
>> + if (control == FSEVENT_FILTER_REMOVE) {
>> + list_del(&(pfilter->list));
>> + kfree(pfilter);
>> + } else
>> + set_fsevent_mask(&(pfilter->mask), mask, control);
>> + }
>> +
>> + if ((type & FSEVENT_FILTER_UID) == FSEVENT_FILTER_UID) {
>> + ufilter = find_uid_filter(&(listenerp->uid_filter_list_head),
>> + filter->id.uid);
>> + if (unlikely(ufilter == NULL))
>> + return;
>> +
>> + if (control == FSEVENT_FILTER_REMOVE) {
>> + list_del(&(ufilter->list));
>> + kfree(ufilter);
>> + } else
>> + set_fsevent_mask(&(ufilter->mask), mask, control);
>> + }
>> +
>> + if ((type & FSEVENT_FILTER_GID) == FSEVENT_FILTER_GID) {
>> + gfilter = find_gid_filter(&(listenerp->gid_filter_list_head),
>> + filter->id.gid);
>> + if (unlikely(gfilter == NULL))
>> + return;
>> +
>> + if (control == FSEVENT_FILTER_REMOVE) {
>> + list_del(&(gfilter->list));
>> + kfree(gfilter);
>> + } else
>> + set_fsevent_mask(&(gfilter->mask), mask, control);
>> + }
>> +
>> +out:
>> + fsevent_ack(type, pid, 0);
>> +}
>> +
>> +static listener * find_fsevent_listener(pid_t pid)
>> +{
>> + listener * listenerp = NULL;
>> + spin_lock(&listener_list_lock);
>> + list_for_each_entry(listenerp, &listener_list_head, list) {
>> + if (listenerp->pid == pid) {
>> + spin_unlock(&listener_list_lock);
>> + return listenerp;
>> + }
>> + }
>> + spin_unlock(&listener_list_lock);
>> + return NULL;
>> +}
>> +
>> +static void cleanup_dead_listener(listener * x)
>> +{
>> + pid_filter * p = NULL, * pq = NULL;
>> + uid_filter * u = NULL, * uq = NULL;
>> + gid_filter * g = NULL, * gq = NULL;
>> +
>> + if (p == NULL)
>> + return;
>> +
>> + list_del(&(x->list));
>> +
>> + list_for_each_entry_safe(p, pq, &(x->pid_filter_list_head), list) {
>> + list_del(&(p->list));
>> + kfree(p);
>> + }
>> +
>> + list_for_each_entry_safe(u, uq, &(x->uid_filter_list_head), list) {
>> + list_del(&(u->list));
>> + kfree(u);
>> + }
>> +
>> + list_for_each_entry_safe(g, gq, &(x->gid_filter_list_head), list) {
>> + list_del(&(g->list));
>> + kfree(g);
>> + }
>> +
>> + kfree(x);
>> +}
>> +
>> +static void fsevent_recv(struct sock *sk, int len)
>> +{
>> + struct sk_buff *skb = NULL;
>> + struct nlmsghdr *nlhdr = NULL;
>> + struct fsevent_filter * filter = NULL;
>> + pid_t pid;
>> +
>> + while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
>> + skb_get(skb);
>> + if (skb->len >= FSEVENT_FILTER_MSGSIZE) {
>> + nlhdr = (struct nlmsghdr *)skb->data;
>> + filter = NLMSG_DATA(nlhdr);
>> + pid = NETLINK_CREDS(skb)->pid;
>> + if (find_fsevent_listener(pid) == NULL)
>> + atomic_inc(&fsevent_listener_num);
>> + set_fsevent_filter(filter, pid);
>> + }
>> + kfree_skb(skb);
>> + }
>> +}
>> +
>> +#define DEFINE_FILTER_MATCH_FUNC(filtertype, key) \
>> + static int match_##filtertype(listener * p, \
>> + struct fsevent * event, \
>> + struct sk_buff * skb) \
>> + { \
>> + int ret = 0; \
>> + filtertype * xfilter = NULL; \
>> + struct sk_buff * skb2 = NULL; \
>> + struct list_head * head = &(p->key##_filter_list_head); \
>> + list_for_each_entry(xfilter, head, list) { \
>> + if (xfilter->key != event->key) \
>> + continue; \
>> + ret = filter_fsevent(xfilter->mask, event->type); \
>> + if ( ret != 0) \
>> + return -1; \
>> + skb2 = skb_clone(skb, GFP_KERNEL); \
>> + if (skb2 == NULL) \
>> + return -ENOMEM; \
>> + NETLINK_CB(skb2).dst_group = 0; \
>> + NETLINK_CB(skb2).dst_pid = p->pid; \
>> + NETLINK_CB(skb2).pid = 0; \
>> + return (netlink_unicast(fsevent_sock, skb2, \
>> + p->pid, MSG_DONTWAIT)); \
>> + } \
>> + return -ENODEV; \
>> + } \
>> +
>> +DEFINE_FILTER_MATCH_FUNC(pid_filter, pid)
>> +
>> +DEFINE_FILTER_MATCH_FUNC(uid_filter, uid)
>> +
>> +DEFINE_FILTER_MATCH_FUNC(gid_filter, gid)
>> +
>> +#define MATCH_XID(key, listenerp, event, skb) \
>> + ret = match_##key##_filter(listenerp, event, skb); \
>> + if (ret == 0) { \
>> + kfree_skb(skb); \
>> + continue; \
>> + } \
>> + do {} while (0) \
>> +
>> +static int fsevent_send_to_process(struct sk_buff * skb)
>> +{
>> + listener * p = NULL, * q = NULL;
>> + struct fsevent * event = NULL;
>> + struct sk_buff * skb2 = NULL;
>> + int ret = 0;
>> +
>> + event = (struct fsevent *)(skb->data + sizeof(struct nlmsghdr));
>> + spin_lock(&listener_list_lock);
>> + list_for_each_entry_safe(p, q, &listener_list_head, list) {
>> + MATCH_XID(pid, p, event, skb);
>> + MATCH_XID(uid, p, event, skb);
>> + MATCH_XID(gid, p, event, skb);
>> +
>> + if (filter_fsevent(p->mask, event->type) == 0) {
>> + skb2 = skb_clone(skb, GFP_KERNEL);
>> + if (skb2 == NULL)
>> + return -ENOMEM;
>> + NETLINK_CB(skb2).dst_group = 0;
>> + NETLINK_CB(skb2).dst_pid = p->pid;
>> + NETLINK_CB(skb2).pid = 0;
>> + ret = netlink_unicast(fsevent_sock, skb2,
>> + p->pid, MSG_DONTWAIT);
>> + if (ret == -ECONNREFUSED) {
>> + atomic_dec(&fsevent_listener_num);
>> + cleanup_dead_listener(p);
>> + }
>> + }
>> + }
>> + spin_unlock(&listener_list_lock);
>>
>
> Systems with global locks do not scale well I think...
> Even if it only called from kfseventd thread.
> You should use per-cpu locks here as long as you use per-cpu queue.
>
>
>> + return ret;
>> +}
>> +
>> +static int kfseventd(void * bind_to_cpu)
>> +{
>> + struct sk_buff * skb = NULL;
>> + //int cpu = (unsigned long) bind_to_cpu;
>> + current->flags |= PF_NOFREEZE;
>> + set_current_state(TASK_INTERRUPTIBLE);
>> +
>> + while (!kthread_should_stop()) {
>> +
>> + while((skb = skb_dequeue(&get_cpu_var(fsevent_send_queue)))
>> + != NULL) {
>> + fsevent_send_to_process(skb);
>> + put_cpu_var(fsevent_send_queue);
>> + }
>> + set_current_state(TASK_INTERRUPTIBLE);
>> + schedule();
>>
>
> Scheduling after each message sent?
> Why don't you use keventd in this case?
>
your suggest is very great, that will reduce amount of code.
>
>> + set_current_state(TASK_RUNNING);
>> + }
>> + set_current_state(TASK_RUNNING);
>> + return 0;
>> +}
>> +
>> +#ifdef CONFIG_HOTPLUG_CPU
>> +static void takeover_fsevent(void * hcpu)
>> +{
>> + struct sk_buff * skb = NULL;
>> + int hotcpu = (unsigned long)hcpu;
>> + struct sk_buff_head * fsevent_queue =
>> + &per_cpu(fsevent_send_queue, hotcpu);
>> +
>> + while((skb = skb_dequeue(fsevent_queue)) != NULL) {
>> + fsevent_send_to_process(skb);
>> + }
>> +}
>> +#endif
>> +
>> +
>> +static int __devinit cpu_callback(struct notifier_block *nfb,
>> + unsigned long action,
>> + void *hcpu)
>> +{
>> + int hotcpu = (unsigned long)hcpu;
>> + struct task_struct *p;
>> +
>> + switch (action) {
>> + case CPU_UP_PREPARE:
>> + p = kthread_create(kfseventd, hcpu, "kfseventd/%d", hotcpu);
>> + if (IS_ERR(p)) {
>> + printk("kfseventd for %i failed\n", hotcpu);
>> + return NOTIFY_BAD;
>> + }
>> + kthread_bind(p, hotcpu);
>> + per_cpu(kfseventd_task, hotcpu) = p;
>> + break;
>> + case CPU_ONLINE:
>> + wake_up_process(per_cpu(kfseventd_task, hotcpu));
>> + break;
>> +#ifdef CONFIG_HOTPLUG_CPU
>> + case CPU_UP_CANCELED:
>> + /* Unbind so it can run. Fall thru. */
>> + kthread_bind(per_cpu(kfseventd, hotcpu),
>> + any_online_cpu(cpu_online_map));
>> + case CPU_DEAD:
>> + p = per_cpu(kfseventd, hotcpu);
>> + per_cpu(kfseventd, hotcpu) = NULL;
>> + kthread_stop(p);
>> + takeover_fsevent(hotcpu);
>> + break;
>> +#endif /* CONFIG_HOTPLUG_CPU */
>> + }
>> + return NOTIFY_OK;
>> +}
>> +
>> +static struct notifier_block __devinitdata cpu_nfb = {
>> + .notifier_call = cpu_callback
>> +};
>> +
>> +static int __init fsevent_init(void)
>> +{
>> + int cpu;
>> + struct sk_buff_head * listptr;
>> + void * hotcpu;
>> +
>> + fsevent_sock = netlink_kernel_create(NETLINK_FSEVENT, 0,
>> + fsevent_recv, THIS_MODULE);
>> + if (!fsevent_sock)
>> + return -EIO;
>> + for_each_cpu(cpu) {
>> + listptr = &per_cpu(fsevent_send_queue, cpu);
>> + skb_queue_head_init(listptr);
>> + }
>> +
>> + hotcpu = (void *)(long)smp_processor_id();
>> + cpu_callback(&cpu_nfb, CPU_UP_PREPARE, hotcpu);
>> + cpu_callback(&cpu_nfb, CPU_ONLINE, hotcpu);
>> + register_cpu_notifier(&cpu_nfb);
>> +
>> + return 0;
>> +}
>> +
>> +static void __exit fsevent_exit(void)
>> +{
>> + sock_release(fsevent_sock->sk_socket);
>>
>
> Hmm, I doubt it is right deinitialization...
>
You are right, I missed cleaning up listener list.
>
>> +}
>> +
>> +module_init(fsevent_init);
>> +module_exit(fsevent_exit);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_AUTHOR("Yi Yang <yang.y.yi@gmail.com>");
>> +MODULE_DESCRIPTION("File System Events Reporter");
>>
>>
>
>

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