File: [Development] / linux-2.6-xfs / split-patches / Attic / relayfs (download)
Revision 1.2, Mon Aug 29 15:50:38 2005 UTC (12 years, 1 month ago) by nathans.longdrop.melbourne.sgi.com
Branch: MAIN
Changes since 1.1: +14 -14
lines
Merge up to 2.6.13.
Merge of 2.6.x-xfs-melb:linux:23660a by kenmcd.
|
%patch
Index: 2.6.x-xfs/Documentation/filesystems/relayfs.txt
===================================================================
--- 2.6.x-xfs.orig/Documentation/filesystems/relayfs.txt 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/Documentation/filesystems/relayfs.txt 2005-08-29 13:29:27.795802385 +1000
@@ -0,0 +1,214 @@
+
+relayfs - a high-speed data relay filesystem
+============================================
+
+relayfs is a filesystem designed to provide an efficient mechanism for
+tools and facilities to relay large and potentially sustained streams
+of data from kernel space to user space.
+
+The main abstraction of relayfs is the 'channel'. A channel consists
+of a set of per-cpu kernel buffers each represented by a file in the
+relayfs filesystem. Kernel clients write into a channel using
+efficient write functions which automatically log to the current cpu's
+channel buffer. User space applications mmap() the per-cpu files and
+retrieve the data as it becomes available.
+
+The format of the data logged into the channel buffers is completely
+up to the relayfs client; relayfs does however provide hooks which
+allow clients to impose some stucture on the buffer data. Nor does
+relayfs implement any form of data filtering - this also is left to
+the client. The purpose is to keep relayfs as simple as possible.
+
+This document provides an overview of the relayfs API. The details of
+the function parameters are documented along with the functions in the
+filesystem code - please see that for details.
+
+
+The relayfs user space API
+==========================
+
+relayfs implements basic file operations for user space access to
+relayfs channel buffer data. Here are the file operations that are
+available and some comments regarding their behavior:
+
+open() enables user to open an _existing_ buffer.
+
+mmap() results in channel buffer being mapped into the caller's
+ memory space.
+
+poll() POLLIN/POLLRDNORM/POLLERR supported. User applications are
+ notified when sub-buffer boundaries are crossed.
+
+close() decrements the channel buffer's refcount. When the refcount
+ reaches 0 i.e. when no process or kernel client has the buffer
+ open, the channel buffer is freed.
+
+
+In order for a user application to make use of relayfs files, the
+relayfs filesystem must be mounted. For example,
+
+ mount -t relayfs relayfs /mnt/relay
+
+NOTE: relayfs doesn't need to be mounted for kernel clients to create
+ or use channels - it only needs to be mounted when user space
+ applications need access to the buffer data.
+
+
+The relayfs kernel API
+======================
+
+Here's a summary of the API relayfs provides to in-kernel clients:
+
+
+ channel management functions:
+
+ relay_open(base_filename, parent, subbuf_size, n_subbufs,
+ overwrite, callbacks)
+ relay_close(chan)
+ relay_flush(chan)
+ relay_reset(chan)
+ relayfs_create_dir(name, parent)
+ relayfs_remove_dir(dentry)
+ relay_commit(buf, reserved, count)
+ relay_subbufs_consumed(chan, cpu, subbufs_consumed)
+
+ write functions:
+
+ relay_write(chan, data, length)
+ __relay_write(chan, data, length)
+ relay_reserve(chan, length)
+
+ callbacks:
+
+ subbuf_start(buf, subbuf, prev_subbuf_idx, prev_subbuf)
+ deliver(buf, subbuf_idx, subbuf)
+ buf_mapped(buf, filp)
+ buf_unmapped(buf, filp)
+ buf_full(buf, subbuf_idx)
+
+
+A relayfs channel is made of up one or more per-cpu channel buffers,
+each implemented as a circular buffer subdivided into one or more
+sub-buffers.
+
+relay_open() is used to create a channel, along with its per-cpu
+channel buffers. Each channel buffer will have an associated file
+created for it in the relayfs filesystem, which can be opened and
+mmapped from user space if desired. The files are named
+basename0...basenameN-1 where N is the number of online cpus, and by
+default will be created in the root of the filesystem. If you want a
+directory structure to contain your relayfs files, you can create it
+with relayfs_create_dir() and pass the parent directory to
+relay_open(). Clients are responsible for cleaning up any directory
+structure they create when the channel is closed - use
+relayfs_remove_dir() for that.
+
+The total size of each per-cpu buffer is calculated by multiplying the
+number of sub-buffers by the sub-buffer size passed into relay_open().
+The idea behind sub-buffers is that they're basically an extension of
+double-buffering to N buffers, and they also allow applications to
+easily implement random-access-on-buffer-boundary schemes, which can
+be important for some high-volume applications. The number and size
+of sub-buffers is completely dependent on the application and even for
+the same application, different conditions will warrant different
+values for these parameters at different times. Typically, the right
+values to use are best decided after some experimentation; in general,
+though, it's safe to assume that having only 1 sub-buffer is a bad
+idea - you're guaranteed to either overwrite data or lose events
+depending on the channel mode being used.
+
+relayfs channels can be opened in either of two modes - 'overwrite' or
+'no-overwrite'. In overwrite mode, writes continuously cycle around
+the buffer and will never fail, but will unconditionally overwrite old
+data regardless of whether it's actually been consumed. In
+no-overwrite mode, writes will fail i.e. data will be lost, if the
+number of unconsumed sub-buffers equals the total number of
+sub-buffers in the channel. In this mode, the client is reponsible
+for notifying relayfs when sub-buffers have been consumed via
+relay_subbufs_consumed(). A full buffer will become 'unfull' and
+logging will continue once the client calls relay_subbufs_consumed()
+again. When a buffer becomes full, the buf_full() callback is invoked
+to notify the client. In both modes, the subbuf_start() callback will
+notify the client whenever a sub-buffer boundary is crossed. This can
+be used to write header information into the new sub-buffer or fill in
+header information reserved in the previous sub-buffer. One piece of
+information that's useful to save in a reserved header slot is the
+number of bytes of 'padding' for a sub-buffer, which is the amount of
+unused space at the end of a sub-buffer. The padding count for each
+sub-buffer is contained in an array in the rchan_buf struct passed
+into the subbuf_start() callback: rchan_buf->padding[prev_subbuf_idx]
+can be used to to get the padding for the just-finished sub-buffer.
+subbuf_start() is also called for the first sub-buffer in each channel
+buffer when the channel is created. The mode is specified to
+relay_open() using the overwrite parameter.
+
+kernel clients write data into the current cpu's channel buffer using
+relay_write() or __relay_write(). relay_write() is the main logging
+function - it uses local_irqsave() to protect the buffer and should be
+used if you might be logging from interrupt context. If you know
+you'll never be logging from interrupt context, you can use
+__relay_write(), which only disables preemption. These functions
+don't return a value, so you can't determine whether or not they
+failed - the assumption is that you wouldn't want to check a return
+value in the fast logging path anyway, and that they'll always succeed
+unless the buffer is full and in no-overwrite mode, in which case
+you'll be notified via the buf_full() callback.
+
+relay_reserve() is used to reserve a slot in a channel buffer which
+can be written to later. This would typically be used in applications
+that need to write directly into a channel buffer without having to
+stage data in a temporary buffer beforehand. Because the actual write
+may not happen immediately after the slot is reserved, applications
+using relay_reserve() can call relay_commit() to notify relayfs when
+the slot has actually been written. When all the reserved slots have
+been committed, the deliver() callback is invoked to notify the client
+that a guaranteed full sub-buffer has been produced. Because the
+write is under control of the client and is separated from the
+reserve, relay_reserve() doesn't protect the buffer at all - it's up
+to the client to provide the appropriate synchronization when using
+relay_reserve().
+
+The client calls relay_close() when it's finished using the channel.
+The channel and its associated buffers are destroyed when there are no
+longer any references to any of the channel buffers. relay_flush()
+forces a sub-buffer switch on all the channel buffers, and can be used
+to finalize and process the last sub-buffers before the channel is
+closed.
+
+Some applications may want to keep a channel around and re-use it
+rather than open and close a new channel for each use. relay_reset()
+can be used for this purpose - it resets a channel to its initial
+state without reallocating channel buffer memory or destroying
+existing mappings. It should however only be called when it's safe to
+do so i.e. when the channel isn't currently being written to.
+
+Finally, there are a couple of utility callbacks that can be used for
+different purposes. buf_mapped() is called whenever a channel buffer
+is mmapped from user space and buf_unmapped() is called when it's
+unmapped. The client can use this notification to trigger actions
+within the kernel application, such as enabling/disabling logging to
+the channel.
+
+
+Resources
+=========
+
+For news, example code, mailing list, etc. see the relayfs homepage:
+
+ http://relayfs.sourceforge.net
+
+
+Credits
+=======
+
+The ideas and specs for relayfs came about as a result of discussions
+on tracing involving the following:
+
+Michel Dagenais <michel.dagenais@polymtl.ca>
+Richard Moore <richardj_moore@uk.ibm.com>
+Bob Wisniewski <bob@watson.ibm.com>
+Karim Yaghmour <karim@opersys.com>
+Tom Zanussi <zanussi@us.ibm.com>
+
+Also thanks to Hubertus Franke for a lot of useful suggestions and bug
+reports.
Index: 2.6.x-xfs/fs/Kconfig
===================================================================
--- 2.6.x-xfs.orig/fs/Kconfig 2005-08-29 13:28:11.622689315 +1000
+++ 2.6.x-xfs/fs/Kconfig 2005-08-29 13:29:27.797755242 +1000
@@ -878,6 +878,18 @@
To compile this as a module, choose M here: the module will be called
ramfs.
+config RELAYFS_FS
+ tristate "Relayfs file system support"
+ ---help---
+ Relayfs is a high-speed data relay filesystem designed to provide
+ an efficient mechanism for tools and facilities to relay large
+ amounts of data from kernel space to user space.
+
+ To compile this code as a module, choose M here: the module will be
+ called relayfs.
+
+ If unsure, say N.
+
endmenu
menu "Miscellaneous filesystems"
Index: 2.6.x-xfs/fs/Makefile
===================================================================
--- 2.6.x-xfs.orig/fs/Makefile 2005-08-29 13:28:11.623665743 +1000
+++ 2.6.x-xfs/fs/Makefile 2005-08-29 13:29:27.798731670 +1000
@@ -99,3 +99,4 @@
obj-$(CONFIG_HOSTFS) += hostfs/
obj-$(CONFIG_HPPFS) += hppfs/
obj-$(CONFIG_DEBUG_FS) += debugfs/
+obj-$(CONFIG_RELAYFS_FS) += relayfs/
Index: 2.6.x-xfs/fs/relayfs/buffers.c
===================================================================
--- 2.6.x-xfs.orig/fs/relayfs/buffers.c 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/fs/relayfs/buffers.c 2005-08-29 13:29:27.799708098 +1000
@@ -0,0 +1,195 @@
+/*
+ * RelayFS buffer management code.
+ *
+ * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/relayfs_fs.h>
+#include "relay.h"
+#include "buffers.h"
+
+/*
+ * close() vm_op implementation for relayfs file mapping.
+ */
+static void relay_file_mmap_close(struct vm_area_struct *vma)
+{
+ struct rchan_buf *buf = vma->vm_private_data;
+ buf->chan->cb->buf_unmapped(buf, vma->vm_file);
+}
+
+/*
+ * nopage() vm_op implementation for relayfs file mapping.
+ */
+static struct page *relay_buf_nopage(struct vm_area_struct *vma,
+ unsigned long address,
+ int *type)
+{
+ struct page *page;
+ struct rchan_buf *buf = vma->vm_private_data;
+ unsigned long offset = address - vma->vm_start;
+
+ if (address > vma->vm_end)
+ return NOPAGE_SIGBUS; /* Disallow mremap */
+ if (!buf)
+ return NOPAGE_OOM;
+
+ page = vmalloc_to_page(buf->start + offset);
+ if (!page)
+ return NOPAGE_OOM;
+ get_page(page);
+
+ if (type)
+ *type = VM_FAULT_MINOR;
+
+ return page;
+}
+
+/*
+ * vm_ops for relay file mappings.
+ */
+static struct vm_operations_struct relay_file_mmap_ops = {
+ .nopage = relay_buf_nopage,
+ .close = relay_file_mmap_close,
+};
+
+/**
+ * relay_mmap_buf: - mmap channel buffer to process address space
+ * @buf: relay channel buffer
+ * @vma: vm_area_struct describing memory to be mapped
+ *
+ * Returns 0 if ok, negative on error
+ *
+ * Caller should already have grabbed mmap_sem.
+ */
+int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
+{
+ unsigned long length = vma->vm_end - vma->vm_start;
+ struct file *filp = vma->vm_file;
+
+ if (!buf)
+ return -EBADF;
+
+ if (length != (unsigned long)buf->chan->alloc_size)
+ return -EINVAL;
+
+ vma->vm_ops = &relay_file_mmap_ops;
+ vma->vm_private_data = buf;
+ buf->chan->cb->buf_mapped(buf, filp);
+
+ return 0;
+}
+
+/**
+ * relay_alloc_buf - allocate a channel buffer
+ * @buf: the buffer struct
+ * @size: total size of the buffer
+ *
+ * Returns a pointer to the resulting buffer, NULL if unsuccessful
+ */
+static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
+{
+ void *mem;
+ int i, j, n_pages;
+
+ size = PAGE_ALIGN(size);
+ n_pages = size >> PAGE_SHIFT;
+
+ buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
+ if (!buf->page_array)
+ return NULL;
+
+ for (i = 0; i < n_pages; i++) {
+ buf->page_array[i] = alloc_page(GFP_KERNEL);
+ if (unlikely(!buf->page_array[i]))
+ goto depopulate;
+ }
+ mem = vmap(buf->page_array, n_pages, GFP_KERNEL, PAGE_KERNEL);
+ if (!mem)
+ goto depopulate;
+
+ memset(mem, 0, size);
+ buf->page_count = n_pages;
+ return mem;
+
+depopulate:
+ for (j = 0; j < i; j++)
+ __free_page(buf->page_array[j]);
+ kfree(buf->page_array);
+ return NULL;
+}
+
+/**
+ * relay_create_buf - allocate and initialize a channel buffer
+ * @alloc_size: size of the buffer to allocate
+ * @n_subbufs: number of sub-buffers in the channel
+ *
+ * Returns channel buffer if successful, NULL otherwise
+ */
+struct rchan_buf *relay_create_buf(struct rchan *chan)
+{
+ struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL);
+ if (!buf)
+ return NULL;
+
+ buf->padding = kmalloc(chan->n_subbufs * sizeof(unsigned *), GFP_KERNEL);
+ if (!buf->padding)
+ goto free_buf;
+
+ buf->commit = kmalloc(chan->n_subbufs * sizeof(unsigned *), GFP_KERNEL);
+ if (!buf->commit)
+ goto free_buf;
+
+ buf->start = relay_alloc_buf(buf, chan->alloc_size);
+ if (!buf->start)
+ goto free_buf;
+
+ buf->chan = chan;
+ kref_get(&buf->chan->kref);
+ return buf;
+
+free_buf:
+ kfree(buf->commit);
+ kfree(buf->padding);
+ kfree(buf);
+ return NULL;
+}
+
+/**
+ * relay_destroy_buf - destroy an rchan_buf struct and associated buffer
+ * @buf: the buffer struct
+ */
+void relay_destroy_buf(struct rchan_buf *buf)
+{
+ struct rchan *chan = buf->chan;
+ int i;
+
+ if (likely(buf->start)) {
+ vunmap(buf->start);
+ for (i = 0; i < buf->page_count; i++)
+ __free_page(buf->page_array[i]);
+ kfree(buf->page_array);
+ }
+ kfree(buf->padding);
+ kfree(buf->commit);
+ kfree(buf);
+ kref_put(&chan->kref, relay_destroy_channel);
+}
+
+/**
+ * relay_remove_buf - remove a channel buffer
+ *
+ * Removes the file from the relayfs fileystem, which also frees the
+ * rchan_buf_struct and the channel buffer. Should only be called from
+ * kref_put().
+ */
+void relay_remove_buf(struct kref *kref)
+{
+ struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
+ relayfs_remove(buf->dentry);
+}
Index: 2.6.x-xfs/fs/relayfs/buffers.h
===================================================================
--- 2.6.x-xfs.orig/fs/relayfs/buffers.h 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/fs/relayfs/buffers.h 2005-08-29 13:29:27.800684526 +1000
@@ -0,0 +1,12 @@
+#ifndef _BUFFERS_H
+#define _BUFFERS_H
+
+/* This inspired by rtai/shmem */
+#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE
+
+extern int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma);
+extern struct rchan_buf *relay_create_buf(struct rchan *chan);
+extern void relay_destroy_buf(struct rchan_buf *buf);
+extern void relay_remove_buf(struct kref *kref);
+
+#endif/* _BUFFERS_H */
Index: 2.6.x-xfs/fs/relayfs/inode.c
===================================================================
--- 2.6.x-xfs.orig/fs/relayfs/inode.c 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/fs/relayfs/inode.c 2005-08-29 13:29:27.801660954 +1000
@@ -0,0 +1,418 @@
+/*
+ * VFS-related code for RelayFS, a high-speed data relay filesystem.
+ *
+ * Copyright (C) 2003-2005 - Tom Zanussi <zanussi@us.ibm.com>, IBM Corp
+ * Copyright (C) 2003-2005 - Karim Yaghmour <karim@opersys.com>
+ *
+ * Based on ramfs, Copyright (C) 2002 - Linus Torvalds
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/relayfs_fs.h>
+#include "relay.h"
+#include "buffers.h"
+
+#define RELAYFS_MAGIC 0xF0B4A981
+
+static struct vfsmount * relayfs_mount;
+static int relayfs_mount_count;
+static kmem_cache_t * relayfs_inode_cachep;
+
+static struct backing_dev_info relayfs_backing_dev_info = {
+ .ra_pages = 0, /* No readahead */
+ .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+};
+
+static struct inode *relayfs_get_inode(struct super_block *sb, int mode,
+ struct rchan *chan)
+{
+ struct rchan_buf *buf = NULL;
+ struct inode *inode;
+
+ if (S_ISREG(mode)) {
+ BUG_ON(!chan);
+ buf = relay_create_buf(chan);
+ if (!buf)
+ return NULL;
+ }
+
+ inode = new_inode(sb);
+ if (!inode) {
+ relay_destroy_buf(buf);
+ return NULL;
+ }
+
+ inode->i_mode = mode;
+ inode->i_uid = 0;
+ inode->i_gid = 0;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_mapping->backing_dev_info = &relayfs_backing_dev_info;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ switch (mode & S_IFMT) {
+ case S_IFREG:
+ inode->i_fop = &relayfs_file_operations;
+ RELAYFS_I(inode)->buf = buf;
+ break;
+ case S_IFDIR:
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+
+ /* directory inodes start off with i_nlink == 2 (for "." entry) */
+ inode->i_nlink++;
+ break;
+ default:
+ break;
+ }
+
+ return inode;
+}
+
+/**
+ * relayfs_create_entry - create a relayfs directory or file
+ * @name: the name of the file to create
+ * @parent: parent directory
+ * @mode: mode
+ * @chan: relay channel associated with the file
+ *
+ * Returns the new dentry, NULL on failure
+ *
+ * Creates a file or directory with the specifed permissions.
+ */
+static struct dentry *relayfs_create_entry(const char *name,
+ struct dentry *parent,
+ int mode,
+ struct rchan *chan)
+{
+ struct dentry *d;
+ struct inode *inode;
+ int error = 0;
+
+ BUG_ON(!name || !(S_ISREG(mode) || S_ISDIR(mode)));
+
+ error = simple_pin_fs("relayfs", &relayfs_mount, &relayfs_mount_count);
+ if (error) {
+ printk(KERN_ERR "Couldn't mount relayfs: errcode %d\n", error);
+ return NULL;
+ }
+
+ if (!parent && relayfs_mount && relayfs_mount->mnt_sb)
+ parent = relayfs_mount->mnt_sb->s_root;
+
+ if (!parent) {
+ simple_release_fs(&relayfs_mount, &relayfs_mount_count);
+ return NULL;
+ }
+
+ parent = dget(parent);
+ down(&parent->d_inode->i_sem);
+ d = lookup_one_len(name, parent, strlen(name));
+ if (IS_ERR(d)) {
+ d = NULL;
+ goto release_mount;
+ }
+
+ if (d->d_inode) {
+ d = NULL;
+ goto release_mount;
+ }
+
+ inode = relayfs_get_inode(parent->d_inode->i_sb, mode, chan);
+ if (!inode) {
+ d = NULL;
+ goto release_mount;
+ }
+
+ d_instantiate(d, inode);
+ dget(d); /* Extra count - pin the dentry in core */
+
+ if (S_ISDIR(mode))
+ parent->d_inode->i_nlink++;
+
+ goto exit;
+
+release_mount:
+ simple_release_fs(&relayfs_mount, &relayfs_mount_count);
+
+exit:
+ up(&parent->d_inode->i_sem);
+ dput(parent);
+ return d;
+}
+
+/**
+ * relayfs_create_file - create a file in the relay filesystem
+ * @name: the name of the file to create
+ * @parent: parent directory
+ * @mode: mode, if not specied the default perms are used
+ * @chan: channel associated with the file
+ *
+ * Returns file dentry if successful, NULL otherwise.
+ *
+ * The file will be created user r on behalf of current user.
+ */
+struct dentry *relayfs_create_file(const char *name, struct dentry *parent,
+ int mode, struct rchan *chan)
+{
+ if (!mode)
+ mode = S_IRUSR;
+ mode = (mode & S_IALLUGO) | S_IFREG;
+
+ return relayfs_create_entry(name, parent, mode, chan);
+}
+
+/**
+ * relayfs_create_dir - create a directory in the relay filesystem
+ * @name: the name of the directory to create
+ * @parent: parent directory, NULL if parent should be fs root
+ *
+ * Returns directory dentry if successful, NULL otherwise.
+ *
+ * The directory will be created world rwx on behalf of current user.
+ */
+struct dentry *relayfs_create_dir(const char *name, struct dentry *parent)
+{
+ int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+ return relayfs_create_entry(name, parent, mode, NULL);
+}
+
+/**
+ * relayfs_remove - remove a file or directory in the relay filesystem
+ * @dentry: file or directory dentry
+ */
+int relayfs_remove(struct dentry *dentry)
+{
+ struct dentry *parent = dentry->d_parent;
+ if (!parent)
+ return -EINVAL;
+
+ parent = dget(parent);
+ down(&parent->d_inode->i_sem);
+ if (dentry->d_inode) {
+ simple_unlink(parent->d_inode, dentry);
+ d_delete(dentry);
+ }
+ dput(dentry);
+ up(&parent->d_inode->i_sem);
+ dput(parent);
+
+ simple_release_fs(&relayfs_mount, &relayfs_mount_count);
+
+ return 0;
+}
+
+/**
+ * relayfs_remove_dir - remove a directory in the relay filesystem
+ * @dentry: directory dentry
+ *
+ * Returns 0 if successful, negative otherwise.
+ */
+int relayfs_remove_dir(struct dentry *dentry)
+{
+ if (!dentry)
+ return -EINVAL;
+
+ return relayfs_remove(dentry);
+}
+
+/**
+ * relayfs_open - open file op for relayfs files
+ * @inode: the inode
+ * @filp: the file
+ *
+ * Increments the channel buffer refcount.
+ */
+int relayfs_open(struct inode *inode, struct file *filp)
+{
+ struct rchan_buf *buf = RELAYFS_I(inode)->buf;
+ kref_get(&buf->kref);
+
+ return 0;
+}
+
+/**
+ * relayfs_mmap - mmap file op for relayfs files
+ * @filp: the file
+ * @vma: the vma describing what to map
+ *
+ * Calls upon relay_mmap_buf to map the file into user space.
+ */
+int relayfs_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ return relay_mmap_buf(RELAYFS_I(inode)->buf, vma);
+}
+
+/**
+ * relayfs_poll - poll file op for relayfs files
+ * @filp: the file
+ * @wait: poll table
+ *
+ * Poll implemention.
+ */
+unsigned int relayfs_poll(struct file *filp, poll_table *wait)
+{
+ unsigned int mask = 0;
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct rchan_buf *buf = RELAYFS_I(inode)->buf;
+
+ if (buf->finalized)
+ return POLLERR;
+
+ if (filp->f_mode & FMODE_READ) {
+ poll_wait(filp, &buf->read_wait, wait);
+ if (!relay_buf_empty(buf))
+ mask |= POLLIN | POLLRDNORM;
+ }
+
+ return mask;
+}
+
+/**
+ * relayfs_release - release file op for relayfs files
+ * @inode: the inode
+ * @filp: the file
+ *
+ * Decrements the channel refcount, as the filesystem is
+ * no longer using it.
+ */
+int relayfs_release(struct inode *inode, struct file *filp)
+{
+ struct rchan_buf *buf = RELAYFS_I(inode)->buf;
+ kref_put(&buf->kref, relay_remove_buf);
+
+ return 0;
+}
+
+/**
+ * relayfs alloc_inode() implementation
+ */
+static struct inode *relayfs_alloc_inode(struct super_block *sb)
+{
+ struct relayfs_inode_info *p = kmem_cache_alloc(relayfs_inode_cachep, SLAB_KERNEL);
+ if (!p)
+ return NULL;
+ p->buf = NULL;
+
+ return &p->vfs_inode;
+}
+
+/**
+ * relayfs destroy_inode() implementation
+ */
+static void relayfs_destroy_inode(struct inode *inode)
+{
+ if (RELAYFS_I(inode)->buf)
+ relay_destroy_buf(RELAYFS_I(inode)->buf);
+
+ kmem_cache_free(relayfs_inode_cachep, RELAYFS_I(inode));
+}
+
+static void init_once(void *p, kmem_cache_t *cachep, unsigned long flags)
+{
+ struct relayfs_inode_info *i = p;
+ if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR)
+ inode_init_once(&i->vfs_inode);
+}
+
+struct file_operations relayfs_file_operations = {
+ .open = relayfs_open,
+ .poll = relayfs_poll,
+ .mmap = relayfs_mmap,
+ .release = relayfs_release,
+};
+
+static struct super_operations relayfs_ops = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+ .alloc_inode = relayfs_alloc_inode,
+ .destroy_inode = relayfs_destroy_inode,
+};
+
+static int relayfs_fill_super(struct super_block * sb, void * data, int silent)
+{
+ struct inode *inode;
+ struct dentry *root;
+ int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = RELAYFS_MAGIC;
+ sb->s_op = &relayfs_ops;
+ inode = relayfs_get_inode(sb, mode, NULL);
+
+ if (!inode)
+ return -ENOMEM;
+
+ root = d_alloc_root(inode);
+ if (!root) {
+ iput(inode);
+ return -ENOMEM;
+ }
+ sb->s_root = root;
+
+ return 0;
+}
+
+static struct super_block * relayfs_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return get_sb_single(fs_type, flags, data, relayfs_fill_super);
+}
+
+static struct file_system_type relayfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "relayfs",
+ .get_sb = relayfs_get_sb,
+ .kill_sb = kill_litter_super,
+};
+
+static int __init init_relayfs_fs(void)
+{
+ int err;
+
+ relayfs_inode_cachep = kmem_cache_create("relayfs_inode_cache",
+ sizeof(struct relayfs_inode_info), 0,
+ 0, init_once, NULL);
+ if (!relayfs_inode_cachep)
+ return -ENOMEM;
+
+ err = register_filesystem(&relayfs_fs_type);
+ if (err)
+ kmem_cache_destroy(relayfs_inode_cachep);
+
+ return err;
+}
+
+static void __exit exit_relayfs_fs(void)
+{
+ unregister_filesystem(&relayfs_fs_type);
+ kmem_cache_destroy(relayfs_inode_cachep);
+}
+
+module_init(init_relayfs_fs)
+module_exit(exit_relayfs_fs)
+
+EXPORT_SYMBOL_GPL(relayfs_open);
+EXPORT_SYMBOL_GPL(relayfs_poll);
+EXPORT_SYMBOL_GPL(relayfs_mmap);
+EXPORT_SYMBOL_GPL(relayfs_release);
+EXPORT_SYMBOL_GPL(relayfs_file_operations);
+EXPORT_SYMBOL_GPL(relayfs_create_dir);
+EXPORT_SYMBOL_GPL(relayfs_remove_dir);
+
+MODULE_AUTHOR("Tom Zanussi <zanussi@us.ibm.com> and Karim Yaghmour <karim@opersys.com>");
+MODULE_DESCRIPTION("Relay Filesystem");
+MODULE_LICENSE("GPL");
+
Index: 2.6.x-xfs/fs/relayfs/Makefile
===================================================================
--- 2.6.x-xfs.orig/fs/relayfs/Makefile 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/fs/relayfs/Makefile 2005-08-29 13:29:27.802637382 +1000
@@ -0,0 +1,4 @@
+obj-$(CONFIG_RELAYFS_FS) += relayfs.o
+
+relayfs-y := relay.o inode.o buffers.o
+
Index: 2.6.x-xfs/fs/relayfs/relay.c
===================================================================
--- 2.6.x-xfs.orig/fs/relayfs/relay.c 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/fs/relayfs/relay.c 2005-08-29 13:29:27.808495951 +1000
@@ -0,0 +1,545 @@
+/*
+ * Public API and common code for RelayFS.
+ *
+ * See Documentation/filesystems/relayfs.txt for an overview of relayfs.
+ *
+ * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/errno.h>
+#include <linux/stddef.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/relayfs_fs.h>
+#include "relay.h"
+#include "buffers.h"
+
+/**
+ * relay_buf_empty - boolean, is the channel buffer empty?
+ * @buf: channel buffer
+ *
+ * Returns 1 if the buffer is empty, 0 otherwise.
+ */
+int relay_buf_empty(struct rchan_buf *buf)
+{
+ int produced = atomic_read(&buf->subbufs_produced);
+ int consumed = atomic_read(&buf->subbufs_consumed);
+
+ return (produced - consumed) ? 0 : 1;
+}
+
+/**
+ * relay_buf_full - boolean, is the channel buffer full?
+ * @buf: channel buffer
+ *
+ * Returns 1 if the buffer is full, 0 otherwise.
+ */
+static inline int relay_buf_full(struct rchan_buf *buf)
+{
+ int produced, consumed;
+
+ if (buf->chan->overwrite)
+ return 0;
+
+ produced = atomic_read(&buf->subbufs_produced);
+ consumed = atomic_read(&buf->subbufs_consumed);
+
+ return (produced - consumed > buf->chan->n_subbufs - 1) ? 1 : 0;
+}
+
+/*
+ * High-level relayfs kernel API and associated functions.
+ */
+
+/*
+ * rchan_callback implementations defining default channel behavior. Used
+ * in place of corresponding NULL values in client callback struct.
+ */
+
+/*
+ * subbuf_start() default callback. Does nothing.
+ */
+static int subbuf_start_default_callback (struct rchan_buf *buf,
+ void *subbuf,
+ unsigned prev_subbuf_idx,
+ void *prev_subbuf)
+{
+ return 0;
+}
+
+/*
+ * deliver() default callback. Does nothing.
+ */
+static void deliver_default_callback (struct rchan_buf *buf,
+ unsigned subbuf_idx,
+ void *subbuf)
+{
+}
+
+/*
+ * buf_mapped() default callback. Does nothing.
+ */
+static void buf_mapped_default_callback(struct rchan_buf *buf,
+ struct file *filp)
+{
+}
+
+/*
+ * buf_unmapped() default callback. Does nothing.
+ */
+static void buf_unmapped_default_callback(struct rchan_buf *buf,
+ struct file *filp)
+{
+}
+
+/*
+ * buf_full() default callback. Does nothing.
+ */
+static void buf_full_default_callback(struct rchan_buf *buf,
+ unsigned subbuf_idx,
+ void *subbuf)
+{
+}
+
+/* relay channel default callbacks */
+static struct rchan_callbacks default_channel_callbacks = {
+ .subbuf_start = subbuf_start_default_callback,
+ .deliver = deliver_default_callback,
+ .buf_mapped = buf_mapped_default_callback,
+ .buf_unmapped = buf_unmapped_default_callback,
+ .buf_full = buf_full_default_callback,
+};
+
+/**
+ * wakeup_readers - wake up readers waiting on a channel
+ * @private: the channel buffer
+ *
+ * This is the work function used to defer reader waking. The
+ * reason waking is deferred is that calling directly from write
+ * causes problems if you're writing from say the scheduler.
+ */
+static void wakeup_readers(void *private)
+{
+ struct rchan_buf *buf = private;
+ wake_up_interruptible(&buf->read_wait);
+}
+
+/**
+ * get_next_subbuf - return next sub-buffer within channel buffer
+ * @buf: channel buffer
+ */
+static inline void *get_next_subbuf(struct rchan_buf *buf)
+{
+ void *next = buf->data + buf->chan->subbuf_size;
+ if (next >= buf->start + buf->chan->subbuf_size * buf->chan->n_subbufs)
+ next = buf->start;
+
+ return next;
+}
+
+/**
+ * __relay_reset - reset a channel buffer
+ * @buf: the channel buffer
+ * @init: 1 if this is a first-time initialization
+ *
+ * See relay_reset for description of effect.
+ */
+static inline void __relay_reset(struct rchan_buf *buf, int init)
+{
+ int i;
+
+ if (init) {
+ init_waitqueue_head(&buf->read_wait);
+ kref_init(&buf->kref);
+ INIT_WORK(&buf->wake_readers, NULL, NULL);
+ } else {
+ cancel_delayed_work(&buf->wake_readers);
+ flush_scheduled_work();
+ }
+
+ atomic_set(&buf->subbufs_produced, 0);
+ atomic_set(&buf->subbufs_consumed, 0);
+ atomic_set(&buf->unfull, 0);
+ buf->finalized = 0;
+ buf->data = buf->start;
+ buf->offset = 0;
+
+ for (i = 0; i < buf->chan->n_subbufs; i++) {
+ buf->padding[i] = 0;
+ buf->commit[i] = 0;
+ }
+
+ buf->offset = buf->chan->cb->subbuf_start(buf, buf->data, 0, NULL);
+ buf->commit[0] = buf->offset;
+}
+
+/**
+ * relay_reset - reset the channel
+ * @chan: the channel
+ *
+ * Returns 0 if successful, negative if not.
+ *
+ * This has the effect of erasing all data from all channel buffers
+ * and restarting the channel in its initial state. The buffers
+ * are not freed, so any mappings are still in effect.
+ *
+ * NOTE: Care should be taken that the channel isn't actually
+ * being used by anything when this call is made.
+ */
+void relay_reset(struct rchan *chan)
+{
+ int i;
+
+ if (!chan)
+ return;
+
+ for (i = 0; i < NR_CPUS; i++) {
+ if (!chan->buf[i])
+ continue;
+ __relay_reset(chan->buf[i], 0);
+ }
+}
+
+/**
+ * relay_open_buf - create a new channel buffer in relayfs
+ *
+ * Internal - used by relay_open().
+ */
+static struct rchan_buf *relay_open_buf(struct rchan *chan,
+ const char *filename,
+ struct dentry *parent)
+{
+ struct rchan_buf *buf;
+ struct dentry *dentry;
+
+ /* Create file in fs */
+ dentry = relayfs_create_file(filename, parent, S_IRUSR, chan);
+ if (!dentry)
+ return NULL;
+
+ buf = RELAYFS_I(dentry->d_inode)->buf;
+ buf->dentry = dentry;
+ __relay_reset(buf, 1);
+
+ return buf;
+}
+
+/**
+ * relay_close_buf - close a channel buffer
+ * @buf: channel buffer
+ *
+ * Marks the buffer finalized and restores the default callbacks.
+ * The channel buffer and channel buffer data structure are then freed
+ * automatically when the last reference is given up.
+ */
+static inline void relay_close_buf(struct rchan_buf *buf)
+{
+ buf->finalized = 1;
+ buf->chan->cb = &default_channel_callbacks;
+ cancel_delayed_work(&buf->wake_readers);
+ flush_scheduled_work();
+ kref_put(&buf->kref, relay_remove_buf);
+}
+
+static inline void setup_callbacks(struct rchan *chan,
+ struct rchan_callbacks *cb)
+{
+ if (!cb) {
+ chan->cb = &default_channel_callbacks;
+ return;
+ }
+
+ if (!cb->subbuf_start)
+ cb->subbuf_start = subbuf_start_default_callback;
+ if (!cb->deliver)
+ cb->deliver = deliver_default_callback;
+ if (!cb->buf_mapped)
+ cb->buf_mapped = buf_mapped_default_callback;
+ if (!cb->buf_unmapped)
+ cb->buf_unmapped = buf_unmapped_default_callback;
+ if (!cb->buf_full)
+ cb->buf_full = buf_full_default_callback;
+ chan->cb = cb;
+}
+
+/**
+ * relay_open - create a new relayfs channel
+ * @base_filename: base name of files to create
+ * @parent: dentry of parent directory, NULL for root directory
+ * @subbuf_size: size of sub-buffers
+ * @n_subbufs: number of sub-buffers
+ * @overwrite: overwrite buffer when full?
+ * @cb: client callback functions
+ *
+ * Returns channel pointer if successful, NULL otherwise.
+ *
+ * Creates a channel buffer for each cpu using the sizes and
+ * attributes specified. The created channel buffer files
+ * will be named base_filename0...base_filenameN-1. File
+ * permissions will be S_IRUSR.
+ */
+struct rchan *relay_open(const char *base_filename,
+ struct dentry *parent,
+ unsigned subbuf_size,
+ unsigned n_subbufs,
+ int overwrite,
+ struct rchan_callbacks *cb)
+{
+ int i;
+ struct rchan *chan;
+ char *tmpname;
+
+ if (!base_filename)
+ return NULL;
+
+ if (!(subbuf_size && n_subbufs))
+ return NULL;
+
+ chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL);
+ if (!chan)
+ return NULL;
+
+ chan->version = RELAYFS_CHANNEL_VERSION;
+ chan->overwrite = overwrite;
+ chan->n_subbufs = n_subbufs;
+ chan->subbuf_size = subbuf_size;
+ chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
+ setup_callbacks(chan, cb);
+ kref_init(&chan->kref);
+
+ tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+ if (!tmpname)
+ goto free_chan;
+
+ for_each_online_cpu(i) {
+ sprintf(tmpname, "%s%d", base_filename, i);
+ chan->buf[i] = relay_open_buf(chan, tmpname, parent);
+ if (!chan->buf[i])
+ goto free_bufs;
+ }
+
+ kfree(tmpname);
+ return chan;
+
+free_bufs:
+ for (i = 0; i < NR_CPUS; i++) {
+ if (!chan->buf[i])
+ break;
+ relay_close_buf(chan->buf[i]);
+ }
+ kfree(tmpname);
+
+free_chan:
+ kref_put(&chan->kref, relay_destroy_channel);
+ return NULL;
+}
+
+/**
+ * deliver_check - deliver a guaranteed full sub-buffer if applicable
+ */
+static inline void deliver_check(struct rchan_buf *buf,
+ unsigned subbuf_idx)
+{
+ void *subbuf;
+ unsigned full = buf->chan->subbuf_size - buf->padding[subbuf_idx];
+
+ if (buf->commit[subbuf_idx] == full) {
+ subbuf = buf->start + subbuf_idx * buf->chan->subbuf_size;
+ buf->chan->cb->deliver(buf, subbuf_idx, subbuf);
+ }
+}
+
+/**
+ * do_switch - change subbuf pointer and do related bookkeeping
+ */
+static inline void do_switch(struct rchan_buf *buf, unsigned new, unsigned old)
+{
+ unsigned start = 0;
+ void *old_data = buf->start + old * buf->chan->subbuf_size;
+
+ buf->data = get_next_subbuf(buf);
+ buf->padding[new] = 0;
+ start = buf->chan->cb->subbuf_start(buf, buf->data, old, old_data);
+ buf->offset = buf->commit[new] = start;
+}
+
+/**
+ * relay_switch_subbuf - switch to a new sub-buffer
+ * @buf: channel buffer
+ * @length: size of current event
+ *
+ * Returns either the length passed in or 0 if full.
+
+ * Performs sub-buffer-switch tasks such as invoking callbacks,
+ * updating padding counts, waking up readers, etc.
+ */
+unsigned relay_switch_subbuf(struct rchan_buf *buf, unsigned length)
+{
+ int new, old, produced = atomic_read(&buf->subbufs_produced);
+ unsigned padding;
+
+ if (unlikely(length > buf->chan->subbuf_size))
+ goto toobig;
+
+ if (unlikely(atomic_read(&buf->unfull))) {
+ atomic_set(&buf->unfull, 0);
+ new = produced % buf->chan->n_subbufs;
+ old = (produced - 1) % buf->chan->n_subbufs;
+ do_switch(buf, new, old);
+ return 0;
+ }
+
+ if (unlikely(relay_buf_full(buf)))
+ return 0;
+
+ old = produced % buf->chan->n_subbufs;
+ padding = buf->chan->subbuf_size - buf->offset;
+ buf->padding[old] = padding;
+ deliver_check(buf, old);
+ buf->offset = buf->chan->subbuf_size;
+ atomic_inc(&buf->subbufs_produced);
+
+ if (waitqueue_active(&buf->read_wait)) {
+ PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
+ schedule_delayed_work(&buf->wake_readers, 1);
+ }
+
+ if (unlikely(relay_buf_full(buf))) {
+ void *old_data = buf->start + old * buf->chan->subbuf_size;
+ buf->chan->cb->buf_full(buf, old, old_data);
+ return 0;
+ }
+
+ new = (produced + 1) % buf->chan->n_subbufs;
+ do_switch(buf, new, old);
+
+ if (unlikely(length + buf->offset > buf->chan->subbuf_size))
+ goto toobig;
+
+ return length;
+
+toobig:
+ printk(KERN_WARNING "relayfs: event too large (%u)\n", length);
+ WARN_ON(1);
+ return 0;
+}
+
+/**
+ * relay_commit - add count bytes to a sub-buffer's commit count
+ * @buf: channel buffer
+ * @reserved: reserved address associated with commit
+ * @count: number of bytes committed
+ *
+ * Invokes deliver() callback if sub-buffer is completely written.
+ */
+void relay_commit(struct rchan_buf *buf,
+ void *reserved,
+ unsigned count)
+{
+ unsigned offset, subbuf_idx;
+
+ offset = reserved - buf->start;
+ subbuf_idx = offset / buf->chan->subbuf_size;
+ buf->commit[subbuf_idx] += count;
+ deliver_check(buf, subbuf_idx);
+}
+
+/**
+ * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
+ * @chan: the channel
+ * @cpu: the cpu associated with the channel buffer to update
+ * @subbufs_consumed: number of sub-buffers to add to current buf's count
+ *
+ * Adds to the channel buffer's consumed sub-buffer count.
+ * subbufs_consumed should be the number of sub-buffers newly consumed,
+ * not the total consumed.
+ *
+ * NOTE: kernel clients don't need to call this function if the channel
+ * mode is 'overwrite'.
+ */
+void relay_subbufs_consumed(struct rchan *chan, int cpu, int subbufs_consumed)
+{
+ int produced, consumed;
+ struct rchan_buf *buf;
+
+ if (!chan)
+ return;
+
+ if (cpu >= NR_CPUS || !chan->buf[cpu])
+ return;
+
+ buf = chan->buf[cpu];
+ if (relay_buf_full(buf))
+ atomic_set(&buf->unfull, 1);
+
+ atomic_add(subbufs_consumed, &buf->subbufs_consumed);
+ produced = atomic_read(&buf->subbufs_produced);
+ consumed = atomic_read(&buf->subbufs_consumed);
+ if (consumed > produced)
+ atomic_set(&buf->subbufs_consumed, produced);
+}
+
+/**
+ * relay_destroy_channel - free the channel struct
+ *
+ * Should only be called from kref_put().
+ */
+void relay_destroy_channel(struct kref *kref)
+{
+ struct rchan *chan = container_of(kref, struct rchan, kref);
+ kfree(chan);
+}
+
+/**
+ * relay_close - close the channel
+ * @chan: the channel
+ *
+ * Closes all channel buffers and frees the channel.
+ */
+void relay_close(struct rchan *chan)
+{
+ int i;
+
+ if (!chan)
+ return;
+
+ for (i = 0; i < NR_CPUS; i++) {
+ if (!chan->buf[i])
+ continue;
+ relay_close_buf(chan->buf[i]);
+ }
+
+ kref_put(&chan->kref, relay_destroy_channel);
+}
+
+/**
+ * relay_flush - close the channel
+ * @chan: the channel
+ *
+ * Flushes all channel buffers i.e. forces buffer switch.
+ */
+void relay_flush(struct rchan *chan)
+{
+ int i;
+
+ if (!chan)
+ return;
+
+ for (i = 0; i < NR_CPUS; i++) {
+ if (!chan->buf[i])
+ continue;
+ relay_switch_subbuf(chan->buf[i], 0);
+ }
+}
+
+EXPORT_SYMBOL_GPL(relay_open);
+EXPORT_SYMBOL_GPL(relay_close);
+EXPORT_SYMBOL_GPL(relay_flush);
+EXPORT_SYMBOL_GPL(relay_reset);
+EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
+EXPORT_SYMBOL_GPL(relay_commit);
+EXPORT_SYMBOL_GPL(relay_switch_subbuf);
Index: 2.6.x-xfs/fs/relayfs/relay.h
===================================================================
--- 2.6.x-xfs.orig/fs/relayfs/relay.h 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/fs/relayfs/relay.h 2005-08-29 13:29:27.809472379 +1000
@@ -0,0 +1,12 @@
+#ifndef _RELAY_H
+#define _RELAY_H
+
+struct dentry *relayfs_create_file(const char *name,
+ struct dentry *parent,
+ int mode,
+ struct rchan *chan);
+extern int relayfs_remove(struct dentry *dentry);
+extern int relay_buf_empty(struct rchan_buf *buf);
+extern void relay_destroy_channel(struct kref *kref);
+
+#endif /* _RELAY_H */
Index: 2.6.x-xfs/include/linux/relayfs_fs.h
===================================================================
--- 2.6.x-xfs.orig/include/linux/relayfs_fs.h 2005-05-25 01:08:16.000000000 +1000
+++ 2.6.x-xfs/include/linux/relayfs_fs.h 2005-08-29 13:29:27.811425236 +1000
@@ -0,0 +1,267 @@
+/*
+ * linux/include/linux/relayfs_fs.h
+ *
+ * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
+ *
+ * RelayFS definitions and declarations
+ */
+
+#ifndef _LINUX_RELAYFS_FS_H
+#define _LINUX_RELAYFS_FS_H
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/kref.h>
+
+/*
+ * Tracks changes to rchan_buf struct
+ */
+#define RELAYFS_CHANNEL_VERSION 3
+
+/*
+ * Per-cpu relay channel buffer
+ */
+struct rchan_buf
+{
+ void *start; /* start of channel buffer */
+ void *data; /* start of current sub-buffer */
+ unsigned offset; /* current offset into sub-buffer */
+ atomic_t subbufs_produced; /* count of sub-buffers produced */
+ atomic_t subbufs_consumed; /* count of sub-buffers consumed */
+ atomic_t unfull; /* state has gone from full to not */
+ struct rchan *chan; /* associated channel */
+ wait_queue_head_t read_wait; /* reader wait queue */
+ struct work_struct wake_readers; /* reader wake-up work struct */
+ struct dentry *dentry; /* channel file dentry */
+ struct kref kref; /* channel buffer refcount */
+ struct page **page_array; /* array of current buffer pages */
+ int page_count; /* number of current buffer pages */
+ unsigned *padding; /* padding counts per sub-buffer */
+ unsigned *commit; /* commit counts per sub-buffer */
+ int finalized; /* buffer has been finalized */
+} ____cacheline_aligned;
+
+/*
+ * Relay channel data structure
+ */
+struct rchan
+{
+ u32 version; /* the version of this struct */
+ unsigned subbuf_size; /* sub-buffer size */
+ unsigned n_subbufs; /* number of sub-buffers per buffer */
+ unsigned alloc_size; /* total buffer size allocated */
+ int overwrite; /* overwrite buffer when full? */
+ struct rchan_callbacks *cb; /* client callbacks */
+ struct kref kref; /* channel refcount */
+ void *private_data; /* for user-defined data */
+ struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
+};
+
+/*
+ * Relayfs inode
+ */
+struct relayfs_inode_info
+{
+ struct inode vfs_inode;
+ struct rchan_buf *buf;
+};
+
+static inline struct relayfs_inode_info *RELAYFS_I(struct inode *inode)
+{
+ return container_of(inode, struct relayfs_inode_info, vfs_inode);
+}
+
+/*
+ * Relay channel client callbacks
+ */
+struct rchan_callbacks
+{
+ /*
+ * subbuf_start - called on buffer-switch to a new sub-buffer
+ * @buf: the channel buffer containing the new sub-buffer
+ * @subbuf: the start of the new sub-buffer
+ * @prev_subbuf_idx: the previous sub-buffer's index
+ * @prev_subbuf: the start of the previous sub-buffer
+ *
+ * The client should return the number of bytes it reserves at
+ * the beginning of the sub-buffer, 0 if none.
+ *
+ * NOTE: subbuf_start will also be invoked when the buffer is
+ * created, so that the first sub-buffer can be initialized
+ * if necessary. In this case, prev_subbuf will be NULL.
+ */
+ int (*subbuf_start) (struct rchan_buf *buf,
+ void *subbuf,
+ unsigned prev_subbuf_idx,
+ void *prev_subbuf);
+
+ /*
+ * deliver - deliver a guaranteed full sub-buffer to client
+ * @buf: the channel buffer containing the sub-buffer
+ * @subbuf_idx: the sub-buffer's index
+ * @subbuf: the start of the new sub-buffer
+ *
+ * Only works if relay_commit is also used
+ */
+ void (*deliver) (struct rchan_buf *buf,
+ unsigned subbuf_idx,
+ void *subbuf);
+
+ /*
+ * buf_mapped - relayfs buffer mmap notification
+ * @buf: the channel buffer
+ * @filp: relayfs file pointer
+ *
+ * Called when a relayfs file is successfully mmapped
+ */
+ void (*buf_mapped)(struct rchan_buf *buf,
+ struct file *filp);
+
+ /*
+ * buf_unmapped - relayfs buffer unmap notification
+ * @buf: the channel buffer
+ * @filp: relayfs file pointer
+ *
+ * Called when a relayfs file is successfully unmapped
+ */
+ void (*buf_unmapped)(struct rchan_buf *buf,
+ struct file *filp);
+
+ /*
+ * buf_full - relayfs buffer full notification
+ * @buf: the channel channel buffer
+ * @subbuf_idx: the current sub-buffer's index
+ * @subbuf: the start of the current sub-buffer
+ *
+ * Called when a relayfs buffer becomes full
+ */
+ void (*buf_full)(struct rchan_buf *buf,
+ unsigned subbuf_idx,
+ void *subbuf);
+};
+
+/*
+ * relayfs kernel API, fs/relayfs/relay.c
+ */
+
+struct rchan *relay_open(const char *base_filename,
+ struct dentry *parent,
+ unsigned subbuf_size,
+ unsigned n_subbufs,
+ int overwrite,
+ struct rchan_callbacks *cb);
+extern void relay_close(struct rchan *chan);
+extern void relay_flush(struct rchan *chan);
+extern void relay_subbufs_consumed(struct rchan *chan,
+ int cpu,
+ int subbufs_consumed);
+extern void relay_reset(struct rchan *chan);
+extern unsigned relay_switch_subbuf(struct rchan_buf *buf,
+ unsigned length);
+extern void relay_commit(struct rchan_buf *buf,
+ void *reserved,
+ unsigned count);
+extern struct dentry *relayfs_create_dir(const char *name,
+ struct dentry *parent);
+extern int relayfs_remove_dir(struct dentry *dentry);
+
+/**
+ * relay_write - write data into the channel
+ * @chan: relay channel
+ * @data: data to be written
+ * @length: number of bytes to write
+ *
+ * Writes data into the current cpu's channel buffer.
+ *
+ * Protects the buffer by disabling interrupts. Use this
+ * if you might be logging from interrupt context. Try
+ * __relay_write() if you know you won't be logging from
+ * interrupt context.
+ */
+static inline void relay_write(struct rchan *chan,
+ const void *data,
+ unsigned length)
+{
+ unsigned long flags;
+ struct rchan_buf *buf;
+
+ local_irq_save(flags);
+ buf = chan->buf[smp_processor_id()];
+ if (unlikely(buf->offset + length > chan->subbuf_size))
+ length = relay_switch_subbuf(buf, length);
+ memcpy(buf->data + buf->offset, data, length);
+ buf->offset += length;
+ local_irq_restore(flags);
+}
+
+/**
+ * __relay_write - write data into the channel
+ * @chan: relay channel
+ * @data: data to be written
+ * @length: number of bytes to write
+ *
+ * Writes data into the current cpu's channel buffer.
+ *
+ * Protects the buffer by disabling preemption. Use
+ * relay_write() if you might be logging from interrupt
+ * context.
+ */
+static inline void __relay_write(struct rchan *chan,
+ const void *data,
+ unsigned length)
+{
+ struct rchan_buf *buf;
+
+ buf = chan->buf[get_cpu()];
+ if (unlikely(buf->offset + length > buf->chan->subbuf_size))
+ length = relay_switch_subbuf(buf, length);
+ memcpy(buf->data + buf->offset, data, length);
+ buf->offset += length;
+ put_cpu();
+}
+
+/**
+ * relay_reserve - reserve slot in channel buffer
+ * @chan: relay channel
+ * @length: number of bytes to reserve
+ *
+ * Returns pointer to reserved slot, NULL if full.
+ *
+ * Reserves a slot in the current cpu's channel buffer.
+ * Does not protect the buffer at all - caller must provide
+ * appropriate synchronization.
+ */
+static inline void *relay_reserve(struct rchan *chan, unsigned length)
+{
+ void *reserved;
+ struct rchan_buf *buf = chan->buf[smp_processor_id()];
+
+ if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
+ length = relay_switch_subbuf(buf, length);
+ if (!length)
+ return NULL;
+ }
+ reserved = buf->data + buf->offset;
+ buf->offset += length;
+
+ return reserved;
+}
+
+/*
+ * exported relayfs file operations, fs/relayfs/inode.c
+ */
+
+extern struct file_operations relayfs_file_operations;
+extern int relayfs_open(struct inode *inode, struct file *filp);
+extern unsigned int relayfs_poll(struct file *filp, poll_table *wait);
+extern int relayfs_mmap(struct file *filp, struct vm_area_struct *vma);
+extern int relayfs_release(struct inode *inode, struct file *filp);
+
+#endif /* _LINUX_RELAYFS_FS_H */
+
%diffstat
Documentation/filesystems/relayfs.txt | 214 +++++++++++++
fs/Kconfig | 12
fs/Makefile | 1
fs/relayfs/Makefile | 4
fs/relayfs/buffers.c | 195 ++++++++++++
fs/relayfs/buffers.h | 12
fs/relayfs/inode.c | 418 ++++++++++++++++++++++++++
fs/relayfs/relay.c | 545 ++++++++++++++++++++++++++++++++++
fs/relayfs/relay.h | 12
include/linux/relayfs_fs.h | 267 ++++++++++++++++
10 files changed, 1680 insertions(+)
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