inode.c

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/*
 * SPU file system
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <[email protected]>
 *
 * 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/fsnotify.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/spu.h>
#include <asm/spu_priv1.h>
#include <asm/uaccess.h>

#include "spufs.h"

struct spufs_sb_info {
    int debug;
};

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

static struct spufs_sb_info *spufs_get_sb_info(struct super_block *sb)
{
    return sb->s_fs_info;
}

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_i_callback(struct rcu_head *head)
{
    struct inode *inode = container_of(head, struct inode, i_rcu);
    kmem_cache_free(spufs_inode_cache, SPUFS_I(inode));
}

static void spufs_destroy_inode(struct inode *inode)
{
    call_rcu(&inode->i_rcu, spufs_i_callback);
}

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

    inode_init_once(&ei->vfs_inode);
}

static struct inode *
spufs_new_inode(struct super_block *sb, umode_t 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_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;
    setattr_copy(inode, attr);
    mark_inode_dirty(inode);
    return 0;
}


static int
spufs_new_file(struct super_block *sb, struct dentry *dentry,
        const struct file_operations *fops, umode_t mode,
        size_t size, struct spu_context *ctx)
{
    static const 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_size = size;
    inode->i_private = SPUFS_I(inode)->i_ctx = get_spu_context(ctx);
    d_add(dentry, inode);
out:
    return ret;
}

static void
spufs_evict_inode(struct inode *inode)
{
    struct spufs_inode_info *ei = SPUFS_I(inode);
    clear_inode(inode);
    if (ei->i_ctx)
        put_spu_context(ei->i_ctx);
    if (ei->i_gang)
        put_spu_gang(ei->i_gang);
}

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(&dentry->d_lock);
        if (!(d_unhashed(dentry)) && dentry->d_inode) {
            dget_dlock(dentry);
            __d_drop(dentry);
            spin_unlock(&dentry->d_lock);
            simple_unlink(dir->d_inode, dentry);
            /* XXX: what was dcache_lock protecting here? Other
             * filesystems (IB, configfs) release dcache_lock
             * before unlink */
            dput(dentry);
        } else {
            spin_unlock(&dentry->d_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 */
    int res;
    spufs_prune_dir(dir);
    d_drop(dir);
    res = simple_rmdir(parent, dir);
    /* We have to give up the mm_struct */
    spu_forget(SPUFS_I(dir->d_inode)->i_ctx);
    return res;
}

static int spufs_fill_dir(struct dentry *dir,
        const struct spufs_tree_descr *files, umode_t 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, files->size, 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_nested(&parent->i_mutex, I_MUTEX_PARENT);
    ret = spufs_rmdir(parent, dir);
    mutex_unlock(&parent->i_mutex);
    WARN_ON(ret);

    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      = noop_fsync,
};
EXPORT_SYMBOL_GPL(spufs_context_fops);

static int
spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
        umode_t 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;

    if (spufs_get_sb_info(dir->i_sb)->debug)
        ret = spufs_fill_dir(dentry, spufs_dir_debug_contents,
                mode, ctx);

    if (ret)
        goto out_free_ctx;

    d_instantiate(dentry, inode);
    dget(dentry);
    inc_nlink(dir);
    inc_nlink(dentry->d_inode);
    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 path *path)
{
    int ret;
    struct file *filp;

    ret = get_unused_fd();
    if (ret < 0)
        return ret;

    filp = dentry_open(path, O_RDONLY, current_cred());
    if (IS_ERR(filp)) {
        put_unused_fd(ret);
        return PTR_ERR(filp);
    }

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

static struct spu_context *
spufs_assert_affinity(unsigned int flags, struct spu_gang *gang,
                        struct file *filp)
{
    struct spu_context *tmp, *neighbor, *err;
    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) {
            err = ERR_PTR(-EEXIST);
            goto out_put_neighbor;
        }

        if (gang != neighbor->gang) {
            err = ERR_PTR(-EINVAL);
            goto out_put_neighbor;
        }

        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) {
            err = ERR_PTR(-EEXIST);
            goto out_put_neighbor;
        }
    }

    return neighbor;

out_put_neighbor:
    put_spu_context(neighbor);
    return err;
}

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;
    }
}

static int
spufs_create_context(struct inode *inode, struct dentry *dentry,
            struct vfsmount *mnt, int flags, umode_t mode,
            struct file *aff_filp)
{
    int ret;
    int affinity;
    struct spu_gang *gang;
    struct spu_context *neighbor;
    struct path path = {.mnt = mnt, .dentry = dentry};

    if ((flags & SPU_CREATE_NOSCHED) &&
        !capable(CAP_SYS_NICE))
        return -EPERM;

    if ((flags & (SPU_CREATE_NOSCHED | SPU_CREATE_ISOLATE))
        == SPU_CREATE_ISOLATE)
        return -EINVAL;

    if ((flags & SPU_CREATE_ISOLATE) && !isolated_loader)
        return -ENODEV;

    gang = NULL;
    neighbor = NULL;
    affinity = flags & (SPU_CREATE_AFFINITY_MEM | SPU_CREATE_AFFINITY_SPU);
    if (affinity) {
        gang = SPUFS_I(inode)->i_gang;
        if (!gang)
            return -EINVAL;
        mutex_lock(&gang->aff_mutex);
        neighbor = spufs_assert_affinity(flags, gang, aff_filp);
        if (IS_ERR(neighbor)) {
            ret = PTR_ERR(neighbor);
            goto out_aff_unlock;
        }
    }

    ret = spufs_mkdir(inode, dentry, flags, mode & S_IRWXUGO);
    if (ret)
        goto out_aff_unlock;

    if (affinity) {
        spufs_set_affinity(flags, SPUFS_I(dentry->d_inode)->i_ctx,
                                neighbor);
        if (neighbor)
            put_spu_context(neighbor);
    }

    ret = spufs_context_open(&path);
    if (ret < 0)
        WARN_ON(spufs_rmdir(inode, dentry));

out_aff_unlock:
    if (affinity)
        mutex_unlock(&gang->aff_mutex);
    return ret;
}

static int
spufs_mkgang(struct inode *dir, struct dentry *dentry, umode_t mode)
{
    int ret;
    struct inode *inode;
    struct spu_gang *gang;

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

    ret = 0;
    if (dir->i_mode & S_ISGID) {
        inode->i_gid = dir->i_gid;
        inode->i_mode &= S_ISGID;
    }
    gang = alloc_spu_gang();
    SPUFS_I(inode)->i_ctx = NULL;
    SPUFS_I(inode)->i_gang = gang;
    if (!gang)
        goto out_iput;

    inode->i_op = &simple_dir_inode_operations;
    inode->i_fop = &simple_dir_operations;

    d_instantiate(dentry, inode);
    inc_nlink(dir);
    inc_nlink(dentry->d_inode);
    return ret;

out_iput:
    iput(inode);
out:
    return ret;
}

static int spufs_gang_open(struct path *path)
{
    int ret;
    struct file *filp;

    ret = get_unused_fd();
    if (ret < 0)
        return ret;

    /*
     * get references for dget and mntget, will be released
     * in error path of *_open().
     */
    filp = dentry_open(path, O_RDONLY, current_cred());
    if (IS_ERR(filp)) {
        put_unused_fd(ret);
        return PTR_ERR(filp);
    }

    filp->f_op = &simple_dir_operations;
    fd_install(ret, filp);
    return ret;
}

static int spufs_create_gang(struct inode *inode,
            struct dentry *dentry,
            struct vfsmount *mnt, umode_t mode)
{
    struct path path = {.mnt = mnt, .dentry = dentry};
    int ret;

    ret = spufs_mkgang(inode, dentry, mode & S_IRWXUGO);
    if (!ret) {
        ret = spufs_gang_open(&path);
        if (ret < 0) {
            int err = simple_rmdir(inode, dentry);
            WARN_ON(err);
        }
    }
    return ret;
}


static struct file_system_type spufs_type;

long spufs_create(struct path *path, struct dentry *dentry,
        unsigned int flags, umode_t mode, struct file *filp)
{
    struct inode *dir = path->dentry->d_inode;
    int ret;

    /* check if we are on spufs */
    if (path->dentry->d_sb->s_type != &spufs_type)
        return -EINVAL;

    /* don't accept undefined flags */
    if (flags & (~SPU_CREATE_FLAG_ALL))
        return -EINVAL;

    /* only threads can be underneath a gang */
    if (path->dentry != path->dentry->d_sb->s_root)
        if ((flags & SPU_CREATE_GANG) || !SPUFS_I(dir)->i_gang)
            return -EINVAL;

    mode &= ~current_umask();

    if (flags & SPU_CREATE_GANG)
        ret = spufs_create_gang(dir, dentry, path->mnt, mode);
    else
        ret = spufs_create_context(dir, dentry, path->mnt, flags, mode,
                        filp);
    if (ret >= 0)
        fsnotify_mkdir(dir, dentry);

    return ret;
}

/* File system initialization */
enum {
    Opt_uid, Opt_gid, Opt_mode, Opt_debug, Opt_err,
};

static const match_table_t spufs_tokens = {
    { Opt_uid,   "uid=%d" },
    { Opt_gid,   "gid=%d" },
    { Opt_mode,  "mode=%o" },
    { Opt_debug, "debug" },
    { Opt_err,    NULL  },
};

static int
spufs_parse_options(struct super_block *sb, char *options, struct inode *root)
{
    char *p;
    substring_t args[MAX_OPT_ARGS];

    while ((p = strsep(&options, ",")) != NULL) {
        int token, option;

        if (!*p)
            continue;

        token = match_token(p, spufs_tokens, args);
        switch (token) {
        case Opt_uid:
            if (match_int(&args[0], &option))
                return 0;
            root->i_uid = option;
            break;
        case Opt_gid:
            if (match_int(&args[0], &option))
                return 0;
            root->i_gid = option;
            break;
        case Opt_mode:
            if (match_octal(&args[0], &option))
                return 0;
            root->i_mode = option | S_IFDIR;
            break;
        case Opt_debug:
            spufs_get_sb_info(sb)->debug = 1;
            break;
        default:
            return 0;
        }
    }
    return 1;
}

static void spufs_exit_isolated_loader(void)
{
    free_pages((unsigned long) isolated_loader,
            get_order(isolated_loader_size));
}

static void
spufs_init_isolated_loader(void)
{
    struct device_node *dn;
    const char *loader;
    int size;

    dn = of_find_node_by_path("/spu-isolation");
    if (!dn)
        return;

    loader = of_get_property(dn, "loader", &size);
    if (!loader)
        return;

    /* the loader must be align on a 16 byte boundary */
    isolated_loader = (char *)__get_free_pages(GFP_KERNEL, get_order(size));
    if (!isolated_loader)
        return;

    isolated_loader_size = size;
    memcpy(isolated_loader, loader, size);
    printk(KERN_INFO "spufs: SPU isolation mode enabled\n");
}

static int
spufs_create_root(struct super_block *sb, void *data)
{
    struct inode *inode;
    int ret;

    ret = -ENODEV;
    if (!spu_management_ops)
        goto out;

    ret = -ENOMEM;
    inode = spufs_new_inode(sb, S_IFDIR | 0775);
    if (!inode)
        goto out;

    inode->i_op = &simple_dir_inode_operations;
    inode->i_fop = &simple_dir_operations;
    SPUFS_I(inode)->i_ctx = NULL;
    inc_nlink(inode);

    ret = -EINVAL;
    if (!spufs_parse_options(sb, data, inode))
        goto out_iput;

    ret = -ENOMEM;
    sb->s_root = d_make_root(inode);
    if (!sb->s_root)
        goto out;

    return 0;
out_iput:
    iput(inode);
out:
    return ret;
}

static int
spufs_fill_super(struct super_block *sb, void *data, int silent)
{
    struct spufs_sb_info *info;
    static const struct super_operations s_ops = {
        .alloc_inode = spufs_alloc_inode,
        .destroy_inode = spufs_destroy_inode,
        .statfs = simple_statfs,
        .evict_inode = spufs_evict_inode,
        .show_options = generic_show_options,
    };

    save_mount_options(sb, data);

    info = kzalloc(sizeof(*info), GFP_KERNEL);
    if (!info)
        return -ENOMEM;

    sb->s_maxbytes = MAX_LFS_FILESIZE;
    sb->s_blocksize = PAGE_CACHE_SIZE;
    sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
    sb->s_magic = SPUFS_MAGIC;
    sb->s_op = &s_ops;
    sb->s_fs_info = info;

    return spufs_create_root(sb, data);
}

static struct dentry *
spufs_mount(struct file_system_type *fstype, int flags,
        const char *name, void *data)
{
    return mount_single(fstype, flags, data, spufs_fill_super);
}

static struct file_system_type spufs_type = {
    .owner = THIS_MODULE,
    .name = "spufs",
    .mount = spufs_mount,
    .kill_sb = kill_litter_super,
};

static int __init spufs_init(void)
{
    int ret;

    ret = -ENODEV;
    if (!spu_management_ops)
        goto out;

    ret = -ENOMEM;
    spufs_inode_cache = kmem_cache_create("spufs_inode_cache",
            sizeof(struct spufs_inode_info), 0,
            SLAB_HWCACHE_ALIGN, spufs_init_once);

    if (!spufs_inode_cache)
        goto out;
    ret = spu_sched_init();
    if (ret)
        goto out_cache;
    ret = register_spu_syscalls(&spufs_calls);
    if (ret)
        goto out_sched;
    ret = register_filesystem(&spufs_type);
    if (ret)
        goto out_syscalls;

    spufs_init_isolated_loader();

    return 0;

out_syscalls:
    unregister_spu_syscalls(&spufs_calls);
out_sched:
    spu_sched_exit();
out_cache:
    kmem_cache_destroy(spufs_inode_cache);
out:
    return ret;
}
module_init(spufs_init);

static void __exit spufs_exit(void)
{
    spu_sched_exit();
    spufs_exit_isolated_loader();
    unregister_spu_syscalls(&spufs_calls);
    unregister_filesystem(&spufs_type);
    kmem_cache_destroy(spufs_inode_cache);
}
module_exit(spufs_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnd Bergmann <[email protected]>");