inode.c

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/*
 * Super block/filesystem wide operations
 *
 * Copyright (C) 1996 Peter J. Braam <[email protected]> and 
 * Michael Callahan <[email protected]> 
 * 
 * Rewritten for Linux 2.1.  Peter Braam <[email protected]>
 * Copyright (C) Carnegie Mellon University
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/file.h>
#include <linux/vfs.h>
#include <linux/slab.h>

#include <asm/uaccess.h>

#include <linux/fs.h>
#include <linux/vmalloc.h>

#include <linux/coda.h>
#include <linux/coda_psdev.h>
#include "coda_linux.h"
#include "coda_cache.h"

#include "coda_int.h"

/* VFS super_block ops */
static void coda_evict_inode(struct inode *);
static void coda_put_super(struct super_block *);
static int coda_statfs(struct dentry *dentry, struct kstatfs *buf);

static struct kmem_cache * coda_inode_cachep;

static struct inode *coda_alloc_inode(struct super_block *sb)
{
    struct coda_inode_info *ei;
    ei = kmem_cache_alloc(coda_inode_cachep, GFP_KERNEL);
    if (!ei)
        return NULL;
    memset(&ei->c_fid, 0, sizeof(struct CodaFid));
    ei->c_flags = 0;
    ei->c_uid = 0;
    ei->c_cached_perm = 0;
    spin_lock_init(&ei->c_lock);
    return &ei->vfs_inode;
}

static void coda_i_callback(struct rcu_head *head)
{
    struct inode *inode = container_of(head, struct inode, i_rcu);
    kmem_cache_free(coda_inode_cachep, ITOC(inode));
}

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

static void init_once(void *foo)
{
    struct coda_inode_info *ei = (struct coda_inode_info *) foo;

    inode_init_once(&ei->vfs_inode);
}

int coda_init_inodecache(void)
{
    coda_inode_cachep = kmem_cache_create("coda_inode_cache",
                sizeof(struct coda_inode_info),
                0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
                init_once);
    if (coda_inode_cachep == NULL)
        return -ENOMEM;
    return 0;
}

void coda_destroy_inodecache(void)
{
    /*
     * Make sure all delayed rcu free inodes are flushed before we
     * destroy cache.
     */
    rcu_barrier();
    kmem_cache_destroy(coda_inode_cachep);
}

static int coda_remount(struct super_block *sb, int *flags, char *data)
{
    *flags |= MS_NOATIME;
    return 0;
}

/* exported operations */
static const struct super_operations coda_super_operations =
{
    .alloc_inode    = coda_alloc_inode,
    .destroy_inode  = coda_destroy_inode,
    .evict_inode    = coda_evict_inode,
    .put_super  = coda_put_super,
    .statfs     = coda_statfs,
    .remount_fs = coda_remount,
};

static int get_device_index(struct coda_mount_data *data)
{
    struct fd f;
    struct inode *inode;
    int idx;

    if (data == NULL) {
        printk("coda_read_super: Bad mount data\n");
        return -1;
    }

    if (data->version != CODA_MOUNT_VERSION) {
        printk("coda_read_super: Bad mount version\n");
        return -1;
    }

    f = fdget(data->fd);
    if (!f.file)
        goto Ebadf;
    inode = f.file->f_path.dentry->d_inode;
    if (!S_ISCHR(inode->i_mode) || imajor(inode) != CODA_PSDEV_MAJOR) {
        fdput(f);
        goto Ebadf;
    }

    idx = iminor(inode);
    fdput(f);

    if (idx < 0 || idx >= MAX_CODADEVS) {
        printk("coda_read_super: Bad minor number\n");
        return -1;
    }

    return idx;
Ebadf:
    printk("coda_read_super: Bad file\n");
    return -1;
}

static int coda_fill_super(struct super_block *sb, void *data, int silent)
{
    struct inode *root = NULL;
    struct venus_comm *vc;
    struct CodaFid fid;
    int error;
    int idx;

    idx = get_device_index((struct coda_mount_data *) data);

    /* Ignore errors in data, for backward compatibility */
    if(idx == -1)
        idx = 0;
    
    printk(KERN_INFO "coda_read_super: device index: %i\n", idx);

    vc = &coda_comms[idx];
    mutex_lock(&vc->vc_mutex);

    if (!vc->vc_inuse) {
        printk("coda_read_super: No pseudo device\n");
        error = -EINVAL;
        goto unlock_out;
    }

    if (vc->vc_sb) {
        printk("coda_read_super: Device already mounted\n");
        error = -EBUSY;
        goto unlock_out;
    }

    error = bdi_setup_and_register(&vc->bdi, "coda", BDI_CAP_MAP_COPY);
    if (error)
        goto unlock_out;

    vc->vc_sb = sb;
    mutex_unlock(&vc->vc_mutex);

    sb->s_fs_info = vc;
    sb->s_flags |= MS_NOATIME;
    sb->s_blocksize = 4096; /* XXXXX  what do we put here?? */
    sb->s_blocksize_bits = 12;
    sb->s_magic = CODA_SUPER_MAGIC;
    sb->s_op = &coda_super_operations;
    sb->s_d_op = &coda_dentry_operations;
    sb->s_bdi = &vc->bdi;

    /* get root fid from Venus: this needs the root inode */
    error = venus_rootfid(sb, &fid);
    if ( error ) {
            printk("coda_read_super: coda_get_rootfid failed with %d\n",
               error);
        goto error;
    }
    printk("coda_read_super: rootfid is %s\n", coda_f2s(&fid));
    
    /* make root inode */
        root = coda_cnode_make(&fid, sb);
        if (IS_ERR(root)) {
        error = PTR_ERR(root);
        printk("Failure of coda_cnode_make for root: error %d\n", error);
        goto error;
    } 

    printk("coda_read_super: rootinode is %ld dev %s\n", 
           root->i_ino, root->i_sb->s_id);
    sb->s_root = d_make_root(root);
    if (!sb->s_root) {
        error = -EINVAL;
        goto error;
    }
    return 0;

error:
    mutex_lock(&vc->vc_mutex);
    bdi_destroy(&vc->bdi);
    vc->vc_sb = NULL;
    sb->s_fs_info = NULL;
unlock_out:
    mutex_unlock(&vc->vc_mutex);
    return error;
}

static void coda_put_super(struct super_block *sb)
{
    struct venus_comm *vcp = coda_vcp(sb);
    mutex_lock(&vcp->vc_mutex);
    bdi_destroy(&vcp->bdi);
    vcp->vc_sb = NULL;
    sb->s_fs_info = NULL;
    mutex_unlock(&vcp->vc_mutex);

    printk("Coda: Bye bye.\n");
}

static void coda_evict_inode(struct inode *inode)
{
    truncate_inode_pages(&inode->i_data, 0);
    clear_inode(inode);
    coda_cache_clear_inode(inode);
}

int coda_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
    int err = coda_revalidate_inode(dentry);
    if (!err)
        generic_fillattr(dentry->d_inode, stat);
    return err;
}

int coda_setattr(struct dentry *de, struct iattr *iattr)
{
    struct inode *inode = de->d_inode;
    struct coda_vattr vattr;
    int error;

    memset(&vattr, 0, sizeof(vattr)); 

    inode->i_ctime = CURRENT_TIME_SEC;
    coda_iattr_to_vattr(iattr, &vattr);
    vattr.va_type = C_VNON; /* cannot set type */

    /* Venus is responsible for truncating the container-file!!! */
    error = venus_setattr(inode->i_sb, coda_i2f(inode), &vattr);

    if (!error) {
            coda_vattr_to_iattr(inode, &vattr); 
        coda_cache_clear_inode(inode);
    }
    return error;
}

const struct inode_operations coda_file_inode_operations = {
    .permission = coda_permission,
    .getattr    = coda_getattr,
    .setattr    = coda_setattr,
};

static int coda_statfs(struct dentry *dentry, struct kstatfs *buf)
{
    int error;
    
    error = venus_statfs(dentry, buf);

    if (error) {
        /* fake something like AFS does */
        buf->f_blocks = 9000000;
        buf->f_bfree  = 9000000;
        buf->f_bavail = 9000000;
        buf->f_files  = 9000000;
        buf->f_ffree  = 9000000;
    }

    /* and fill in the rest */
    buf->f_type = CODA_SUPER_MAGIC;
    buf->f_bsize = 4096;
    buf->f_namelen = CODA_MAXNAMLEN;

    return 0; 
}

/* init_coda: used by filesystems.c to register coda */

static struct dentry *coda_mount(struct file_system_type *fs_type,
    int flags, const char *dev_name, void *data)
{
    return mount_nodev(fs_type, flags, data, coda_fill_super);
}

struct file_system_type coda_fs_type = {
    .owner      = THIS_MODULE,
    .name       = "coda",
    .mount      = coda_mount,
    .kill_sb    = kill_anon_super,
    .fs_flags   = FS_BINARY_MOUNTDATA,
};