1 files changed, 609 insertions, 0 deletions
diff --git a/fs/relayfs/inode.c b/fs/relayfs/inode.c
new file mode 100644
index 000000000000..0f7f88d067ad
--- /dev/null
+++ b/fs/relayfs/inode.c
@@ -0,0 +1,609 @@
+/*
+ * 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
+ *
+ *	Returns 0 if successful, negative otherwise.
+ */
+int relayfs_remove(struct dentry *dentry)
+{
+	struct dentry *parent;
+	int error = 0;
+
+	if (!dentry)
+		return -EINVAL;
+	parent = dentry->d_parent;
+	if (!parent)
+		return -EINVAL;
+
+	parent = dget(parent);
+	down(&parent->d_inode->i_sem);
+	if (dentry->d_inode) {
+		if (S_ISDIR(dentry->d_inode->i_mode))
+			error = simple_rmdir(parent->d_inode, dentry);
+		else
+			error = simple_unlink(parent->d_inode, dentry);
+		if (!error)
+			d_delete(dentry);
+	}
+	if (!error)
+		dput(dentry);
+	up(&parent->d_inode->i_sem);
+	dput(parent);
+
+	if (!error)
+		simple_release_fs(&relayfs_mount, &relayfs_mount_count);
+
+	return error;
+}
+
+/**
+ *	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)
+{
+	return relayfs_remove(dentry);
+}
+
+/**
+ *	relayfs_open - open file op for relayfs files
+ *	@inode: the inode
+ *	@filp: the file
+ *
+ *	Increments the channel buffer refcount.
+ */
+static 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.
+ */
+static 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.
+ */
+static 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.
+ */
+static 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_read_consume - update the consumed count for the buffer
+ */
+static void relayfs_read_consume(struct rchan_buf *buf,
+				 size_t read_pos,
+				 size_t bytes_consumed)
+{
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t read_subbuf;
+
+	if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
+		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
+		buf->bytes_consumed = 0;
+	}
+
+	buf->bytes_consumed += bytes_consumed;
+	read_subbuf = read_pos / buf->chan->subbuf_size;
+	if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
+		if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
+		    (buf->offset == subbuf_size))
+			return;
+		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
+		buf->bytes_consumed = 0;
+	}
+}
+
+/**
+ *	relayfs_read_avail - boolean, are there unconsumed bytes available?
+ */
+static int relayfs_read_avail(struct rchan_buf *buf, size_t read_pos)
+{
+	size_t bytes_produced, bytes_consumed, write_offset;
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t produced = buf->subbufs_produced % n_subbufs;
+	size_t consumed = buf->subbufs_consumed % n_subbufs;
+
+	write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
+
+	if (consumed > produced) {
+		if ((produced > n_subbufs) &&
+		    (produced + n_subbufs - consumed <= n_subbufs))
+			produced += n_subbufs;
+	} else if (consumed == produced) {
+		if (buf->offset > subbuf_size) {
+			produced += n_subbufs;
+			if (buf->subbufs_produced == buf->subbufs_consumed)
+				consumed += n_subbufs;
+		}
+	}
+
+	if (buf->offset > subbuf_size)
+		bytes_produced = (produced - 1) * subbuf_size + write_offset;
+	else
+		bytes_produced = produced * subbuf_size + write_offset;
+	bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
+
+	if (bytes_produced == bytes_consumed)
+		return 0;
+
+	relayfs_read_consume(buf, read_pos, 0);
+
+	return 1;
+}
+
+/**
+ *	relayfs_read_subbuf_avail - return bytes available in sub-buffer
+ */
+static size_t relayfs_read_subbuf_avail(size_t read_pos,
+					struct rchan_buf *buf)
+{
+	size_t padding, avail = 0;
+	size_t read_subbuf, read_offset, write_subbuf, write_offset;
+	size_t subbuf_size = buf->chan->subbuf_size;
+
+	write_subbuf = (buf->data - buf->start) / subbuf_size;
+	write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
+	read_subbuf = read_pos / subbuf_size;
+	read_offset = read_pos % subbuf_size;
+	padding = buf->padding[read_subbuf];
+
+	if (read_subbuf == write_subbuf) {
+		if (read_offset + padding < write_offset)
+			avail = write_offset - (read_offset + padding);
+	} else
+		avail = (subbuf_size - padding) - read_offset;
+
+	return avail;
+}
+
+/**
+ *	relayfs_read_start_pos - find the first available byte to read
+ *
+ *	If the read_pos is in the middle of padding, return the
+ *	position of the first actually available byte, otherwise
+ *	return the original value.
+ */
+static size_t relayfs_read_start_pos(size_t read_pos,
+				     struct rchan_buf *buf)
+{
+	size_t read_subbuf, padding, padding_start, padding_end;
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+
+	read_subbuf = read_pos / subbuf_size;
+	padding = buf->padding[read_subbuf];
+	padding_start = (read_subbuf + 1) * subbuf_size - padding;
+	padding_end = (read_subbuf + 1) * subbuf_size;
+	if (read_pos >= padding_start && read_pos < padding_end) {
+		read_subbuf = (read_subbuf + 1) % n_subbufs;
+		read_pos = read_subbuf * subbuf_size;
+	}
+
+	return read_pos;
+}
+
+/**
+ *	relayfs_read_end_pos - return the new read position
+ */
+static size_t relayfs_read_end_pos(struct rchan_buf *buf,
+				   size_t read_pos,
+				   size_t count)
+{
+	size_t read_subbuf, padding, end_pos;
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+
+	read_subbuf = read_pos / subbuf_size;
+	padding = buf->padding[read_subbuf];
+	if (read_pos % subbuf_size + count + padding == subbuf_size)
+		end_pos = (read_subbuf + 1) * subbuf_size;
+	else
+		end_pos = read_pos + count;
+	if (end_pos >= subbuf_size * n_subbufs)
+		end_pos = 0;
+
+	return end_pos;
+}
+
+/**
+ *	relayfs_read - read file op for relayfs files
+ *	@filp: the file
+ *	@buffer: the userspace buffer
+ *	@count: number of bytes to read
+ *	@ppos: position to read from
+ *
+ *	Reads count bytes or the number of bytes available in the
+ *	current sub-buffer being read, whichever is smaller.
+ */
+static ssize_t relayfs_read(struct file *filp,
+			    char __user *buffer,
+			    size_t count,
+			    loff_t *ppos)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct rchan_buf *buf = RELAYFS_I(inode)->buf;
+	size_t read_start, avail;
+	ssize_t ret = 0;
+	void *from;
+
+	down(&inode->i_sem);
+	if(!relayfs_read_avail(buf, *ppos))
+		goto out;
+
+	read_start = relayfs_read_start_pos(*ppos, buf);
+	avail = relayfs_read_subbuf_avail(read_start, buf);
+	if (!avail)
+		goto out;
+
+	from = buf->start + read_start;
+	ret = count = min(count, avail);
+	if (copy_to_user(buffer, from, count)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	relayfs_read_consume(buf, read_start, count);
+	*ppos = relayfs_read_end_pos(buf, read_start, count);
+out:
+	up(&inode->i_sem);
+	return ret;
+}
+
+/**
+ *	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,
+	.read		= relayfs_read,
+	.llseek		= no_llseek,
+	.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_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");
+