Merge /spare/repo/linux-2.6/

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");
+