inode.c

linux 内核源代码

/*
 * SPU file system
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <[e-mail]>
 *
 * 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/file.h>
#include <linux/fs.h>
#include <linux/backing-dev.h>
#include <linux/init.h>
#include <linux/ioctl.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/parser.h>

#include <asm/prom.h>
#include <asm/semaphore.h>
#include <asm/spu.h>
#include <asm/spu_priv1.h>
#include <asm/uaccess.h>

#include "spufs.h"

static struct kmem_cache *spufs_inode_cache;
char *isolated_loader;
static int isolated_loader_size;

static struct inode *
spufs_alloc_inode(struct super_block *sb)
{
	struct spufs_inode_info *ei;

	ei = kmem_cache_alloc(spufs_inode_cache, GFP_KERNEL);
	if (!ei)
		return NULL;

	ei->i_gang = NULL;
	ei->i_ctx = NULL;
	ei->i_openers = 0;

	return &ei->vfs_inode;
}

static void
spufs_destroy_inode(struct inode *inode)
{
	kmem_cache_free(spufs_inode_cache, SPUFS_I(inode));
}

static void
spufs_init_once(struct kmem_cache *cachep, void *p)
{
	struct spufs_inode_info *ei = p;

	inode_init_once(&ei->vfs_inode);
}

static struct inode *
spufs_new_inode(struct super_block *sb, int mode)
{
	struct inode *inode;

	inode = new_inode(sb);
	if (!inode)
		goto out;

	inode->i_mode = mode;
	inode->i_uid = current->fsuid;
	inode->i_gid = current->fsgid;
	inode->i_blocks = 0;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
out:
	return inode;
}

static int
spufs_setattr(struct dentry *dentry, struct iattr *attr)
{
	struct inode *inode = dentry->d_inode;

	if ((attr->ia_valid & ATTR_SIZE) &&
	    (attr->ia_size != inode->i_size))
		return -EINVAL;
	return inode_setattr(inode, attr);
}


static int
spufs_new_file(struct super_block *sb, struct dentry *dentry,
		const struct file_operations *fops, int mode,
		struct spu_context *ctx)
{
	static struct inode_operations spufs_file_iops = {
		.setattr = spufs_setattr,
	};
	struct inode *inode;
	int ret;

	ret = -ENOSPC;
	inode = spufs_new_inode(sb, S_IFREG | mode);
	if (!inode)
		goto out;

	ret = 0;
	inode->i_op = &spufs_file_iops;
	inode->i_fop = fops;
	inode->i_private = SPUFS_I(inode)->i_ctx = get_spu_context(ctx);
	d_add(dentry, inode);
out:
	return ret;
}

static void
spufs_delete_inode(struct inode *inode)
{
	struct spufs_inode_info *ei = SPUFS_I(inode);

	if (ei->i_ctx)
		put_spu_context(ei->i_ctx);
	if (ei->i_gang)
		put_spu_gang(ei->i_gang);
	clear_inode(inode);
}

static void spufs_prune_dir(struct dentry *dir)
{
	struct dentry *dentry, *tmp;

	mutex_lock(&dir->d_inode->i_mutex);
	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
		spin_lock(&dcache_lock);
		spin_lock(&dentry->d_lock);
		if (!(d_unhashed(dentry)) && dentry->d_inode) {
			dget_locked(dentry);
			__d_drop(dentry);
			spin_unlock(&dentry->d_lock);
			simple_unlink(dir->d_inode, dentry);
			spin_unlock(&dcache_lock);
			dput(dentry);
		} else {
			spin_unlock(&dentry->d_lock);
			spin_unlock(&dcache_lock);
		}
	}
	shrink_dcache_parent(dir);
	mutex_unlock(&dir->d_inode->i_mutex);
}

/* Caller must hold parent->i_mutex */
static int spufs_rmdir(struct inode *parent, struct dentry *dir)
{
	/* remove all entries */
	spufs_prune_dir(dir);
	d_drop(dir);

	return simple_rmdir(parent, dir);
}

static int spufs_fill_dir(struct dentry *dir, struct tree_descr *files,
			  int mode, struct spu_context *ctx)
{
	struct dentry *dentry, *tmp;
	int ret;

	while (files->name && files->name[0]) {
		ret = -ENOMEM;
		dentry = d_alloc_name(dir, files->name);
		if (!dentry)
			goto out;
		ret = spufs_new_file(dir->d_sb, dentry, files->ops,
					files->mode & mode, ctx);
		if (ret)
			goto out;
		files++;
	}
	return 0;
out:
	/*
	 * remove all children from dir. dir->inode is not set so don't
	 * just simply use spufs_prune_dir() and panic afterwards :)
	 * dput() looks like it will do the right thing:
	 * - dec parent's ref counter
	 * - remove child from parent's child list
	 * - free child's inode if possible
	 * - free child
	 */
	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
		dput(dentry);
	}

	shrink_dcache_parent(dir);
	return ret;
}

static int spufs_dir_close(struct inode *inode, struct file *file)
{
	struct spu_context *ctx;
	struct inode *parent;
	struct dentry *dir;
	int ret;

	dir = file->f_path.dentry;
	parent = dir->d_parent->d_inode;
	ctx = SPUFS_I(dir->d_inode)->i_ctx;

	mutex_lock(&parent->i_mutex);
	ret = spufs_rmdir(parent, dir);
	mutex_unlock(&parent->i_mutex);
	WARN_ON(ret);

	/* We have to give up the mm_struct */
	spu_forget(ctx);

	return dcache_dir_close(inode, file);
}

const struct file_operations spufs_context_fops = {
	.open		= dcache_dir_open,
	.release	= spufs_dir_close,
	.llseek		= dcache_dir_lseek,
	.read		= generic_read_dir,
	.readdir	= dcache_readdir,
	.fsync		= simple_sync_file,
};
EXPORT_SYMBOL_GPL(spufs_context_fops);

static int
spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
		int mode)
{
	int ret;
	struct inode *inode;
	struct spu_context *ctx;

	ret = -ENOSPC;
	inode = spufs_new_inode(dir->i_sb, mode | S_IFDIR);
	if (!inode)
		goto out;

	if (dir->i_mode & S_ISGID) {
		inode->i_gid = dir->i_gid;
		inode->i_mode &= S_ISGID;
	}
	ctx = alloc_spu_context(SPUFS_I(dir)->i_gang); /* XXX gang */
	SPUFS_I(inode)->i_ctx = ctx;
	if (!ctx)
		goto out_iput;

	ctx->flags = flags;
	inode->i_op = &simple_dir_inode_operations;
	inode->i_fop = &simple_dir_operations;
	if (flags & SPU_CREATE_NOSCHED)
		ret = spufs_fill_dir(dentry, spufs_dir_nosched_contents,
					 mode, ctx);
	else
		ret = spufs_fill_dir(dentry, spufs_dir_contents, mode, ctx);

	if (ret)
		goto out_free_ctx;

	d_instantiate(dentry, inode);
	dget(dentry);
	dir->i_nlink++;
	dentry->d_inode->i_nlink++;
	goto out;

out_free_ctx:
	spu_forget(ctx);
	put_spu_context(ctx);
out_iput:
	iput(inode);
out:
	return ret;
}

static int spufs_context_open(struct dentry *dentry, struct vfsmount *mnt)
{
	int ret;
	struct file *filp;

	ret = get_unused_fd();
	if (ret < 0) {
		dput(dentry);
		mntput(mnt);
		goto out;
	}

	filp = dentry_open(dentry, mnt, O_RDONLY);
	if (IS_ERR(filp)) {
		put_unused_fd(ret);
		ret = PTR_ERR(filp);
		goto out;
	}

	filp->f_op = &spufs_context_fops;
	fd_install(ret, filp);
out:
	return ret;
}

static struct spu_context *
spufs_assert_affinity(unsigned int flags, struct spu_gang *gang,
						struct file *filp)
{
	struct spu_context *tmp, *neighbor;
	int count, node;
	int aff_supp;

	aff_supp = !list_empty(&(list_entry(cbe_spu_info[0].spus.next,
					struct spu, cbe_list))->aff_list);

	if (!aff_supp)
		return ERR_PTR(-EINVAL);

	if (flags & SPU_CREATE_GANG)
		return ERR_PTR(-EINVAL);

	if (flags & SPU_CREATE_AFFINITY_MEM &&
	    gang->aff_ref_ctx &&
	    gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM)
		return ERR_PTR(-EEXIST);

	if (gang->aff_flags & AFF_MERGED)
		return ERR_PTR(-EBUSY);

	neighbor = NULL;
	if (flags & SPU_CREATE_AFFINITY_SPU) {
		if (!filp || filp->f_op != &spufs_context_fops)
			return ERR_PTR(-EINVAL);

		neighbor = get_spu_context(
				SPUFS_I(filp->f_dentry->d_inode)->i_ctx);

		if (!list_empty(&neighbor->aff_list) && !(neighbor->aff_head) &&
		    !list_is_last(&neighbor->aff_list, &gang->aff_list_head) &&
		    !list_entry(neighbor->aff_list.next, struct spu_context,
		    aff_list)->aff_head)
			return ERR_PTR(-EEXIST);

		if (gang != neighbor->gang)
			return ERR_PTR(-EINVAL);

		count = 1;
		list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
			count++;
		if (list_empty(&neighbor->aff_list))
			count++;

		for (node = 0; node < MAX_NUMNODES; node++) {
			if ((cbe_spu_info[node].n_spus - atomic_read(
				&cbe_spu_info[node].reserved_spus)) >= count)
				break;
		}

		if (node == MAX_NUMNODES)
			return ERR_PTR(-EEXIST);
	}

	return neighbor;
}

static void
spufs_set_affinity(unsigned int flags, struct spu_context *ctx,
					struct spu_context *neighbor)
{
	if (flags & SPU_CREATE_AFFINITY_MEM)
		ctx->gang->aff_ref_ctx = ctx;

	if (flags & SPU_CREATE_AFFINITY_SPU) {
		if (list_empty(&neighbor->aff_list)) {
			list_add_tail(&neighbor->aff_list,
				&ctx->gang->aff_list_head);
			neighbor->aff_head = 1;
		}

		if (list_is_last(&neighbor->aff_list, &ctx->gang->aff_list_head)
		    || list_entry(neighbor->aff_list.next, struct spu_context,
							aff_list)->aff_head) {
			list_add(&ctx->aff_list, &neighbor->aff_list);
		} else  {
			list_add_tail(&ctx->aff_list, &neighbor->aff_list);
			if (neighbor->aff_head) {
				neighbor->aff_head = 0;
				ctx->aff_head = 1;
			}
		}

		if (!ctx->gang->aff_ref_ctx)
			ctx->gang->aff_ref_ctx = ctx;
	}
}