vfs_super.c

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/*
 *  linux/fs/9p/vfs_super.c
 *
 * This file contians superblock ops for 9P2000. It is intended that
 * you mount this file system on directories.
 *
 *  Copyright (C) 2004 by Eric Van Hensbergen <[email protected]>
 *  Copyright (C) 2002 by Ron Minnich <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/statfs.h>
#include <linux/magic.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
#include "xattr.h"
#include "acl.h"

static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;

static int v9fs_set_super(struct super_block *s, void *data)
{
    s->s_fs_info = data;
    return set_anon_super(s, data);
}

static void
v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
        int flags, void *data)
{
    sb->s_maxbytes = MAX_LFS_FILESIZE;
    sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
    sb->s_blocksize = 1 << sb->s_blocksize_bits;
    sb->s_magic = V9FS_MAGIC;
    if (v9fs_proto_dotl(v9ses)) {
        sb->s_op = &v9fs_super_ops_dotl;
        sb->s_xattr = v9fs_xattr_handlers;
    } else
        sb->s_op = &v9fs_super_ops;
    sb->s_bdi = &v9ses->bdi;
    if (v9ses->cache)
        sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_CACHE_SIZE;

    sb->s_flags |= MS_ACTIVE | MS_DIRSYNC | MS_NOATIME;
    if (!v9ses->cache)
        sb->s_flags |= MS_SYNCHRONOUS;

#ifdef CONFIG_9P_FS_POSIX_ACL
    if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
        sb->s_flags |= MS_POSIXACL;
#endif

    save_mount_options(sb, data);
}

static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
               const char *dev_name, void *data)
{
    struct super_block *sb = NULL;
    struct inode *inode = NULL;
    struct dentry *root = NULL;
    struct v9fs_session_info *v9ses = NULL;
    umode_t mode = S_IRWXUGO | S_ISVTX;
    struct p9_fid *fid;
    int retval = 0;

    p9_debug(P9_DEBUG_VFS, "\n");

    v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
    if (!v9ses)
        return ERR_PTR(-ENOMEM);

    fid = v9fs_session_init(v9ses, dev_name, data);
    if (IS_ERR(fid)) {
        retval = PTR_ERR(fid);
        /*
         * we need to call session_close to tear down some
         * of the data structure setup by session_init
         */
        goto close_session;
    }

    sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
    if (IS_ERR(sb)) {
        retval = PTR_ERR(sb);
        goto clunk_fid;
    }
    v9fs_fill_super(sb, v9ses, flags, data);

    if (v9ses->cache)
        sb->s_d_op = &v9fs_cached_dentry_operations;
    else
        sb->s_d_op = &v9fs_dentry_operations;

    inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
    if (IS_ERR(inode)) {
        retval = PTR_ERR(inode);
        goto release_sb;
    }

    root = d_make_root(inode);
    if (!root) {
        retval = -ENOMEM;
        goto release_sb;
    }
    sb->s_root = root;
    if (v9fs_proto_dotl(v9ses)) {
        struct p9_stat_dotl *st = NULL;
        st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
        if (IS_ERR(st)) {
            retval = PTR_ERR(st);
            goto release_sb;
        }
        root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
        v9fs_stat2inode_dotl(st, root->d_inode);
        kfree(st);
    } else {
        struct p9_wstat *st = NULL;
        st = p9_client_stat(fid);
        if (IS_ERR(st)) {
            retval = PTR_ERR(st);
            goto release_sb;
        }

        root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
        v9fs_stat2inode(st, root->d_inode, sb);

        p9stat_free(st);
        kfree(st);
    }
    retval = v9fs_get_acl(inode, fid);
    if (retval)
        goto release_sb;
    v9fs_fid_add(root, fid);

    p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
    return dget(sb->s_root);

clunk_fid:
    p9_client_clunk(fid);
close_session:
    v9fs_session_close(v9ses);
    kfree(v9ses);
    return ERR_PTR(retval);

release_sb:
    /*
     * we will do the session_close and root dentry release
     * in the below call. But we need to clunk fid, because we haven't
     * attached the fid to dentry so it won't get clunked
     * automatically.
     */
    p9_client_clunk(fid);
    deactivate_locked_super(sb);
    return ERR_PTR(retval);
}

static void v9fs_kill_super(struct super_block *s)
{
    struct v9fs_session_info *v9ses = s->s_fs_info;

    p9_debug(P9_DEBUG_VFS, " %p\n", s);

    kill_anon_super(s);

    v9fs_session_cancel(v9ses);
    v9fs_session_close(v9ses);
    kfree(v9ses);
    s->s_fs_info = NULL;
    p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
}

static void
v9fs_umount_begin(struct super_block *sb)
{
    struct v9fs_session_info *v9ses;

    v9ses = sb->s_fs_info;
    v9fs_session_begin_cancel(v9ses);
}

static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
    struct v9fs_session_info *v9ses;
    struct p9_fid *fid;
    struct p9_rstatfs rs;
    int res;

    fid = v9fs_fid_lookup(dentry);
    if (IS_ERR(fid)) {
        res = PTR_ERR(fid);
        goto done;
    }

    v9ses = v9fs_dentry2v9ses(dentry);
    if (v9fs_proto_dotl(v9ses)) {
        res = p9_client_statfs(fid, &rs);
        if (res == 0) {
            buf->f_type = rs.type;
            buf->f_bsize = rs.bsize;
            buf->f_blocks = rs.blocks;
            buf->f_bfree = rs.bfree;
            buf->f_bavail = rs.bavail;
            buf->f_files = rs.files;
            buf->f_ffree = rs.ffree;
            buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
            buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
            buf->f_namelen = rs.namelen;
        }
        if (res != -ENOSYS)
            goto done;
    }
    res = simple_statfs(dentry, buf);
done:
    return res;
}

static int v9fs_drop_inode(struct inode *inode)
{
    struct v9fs_session_info *v9ses;
    v9ses = v9fs_inode2v9ses(inode);
    if (v9ses->cache)
        return generic_drop_inode(inode);
    /*
     * in case of non cached mode always drop the
     * the inode because we want the inode attribute
     * to always match that on the server.
     */
    return 1;
}

static int v9fs_write_inode(struct inode *inode,
                struct writeback_control *wbc)
{
    int ret;
    struct p9_wstat wstat;
    struct v9fs_inode *v9inode;
    /*
     * send an fsync request to server irrespective of
     * wbc->sync_mode.
     */
    p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
    v9inode = V9FS_I(inode);
    if (!v9inode->writeback_fid)
        return 0;
    v9fs_blank_wstat(&wstat);

    ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
    if (ret < 0) {
        __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
        return ret;
    }
    return 0;
}

static int v9fs_write_inode_dotl(struct inode *inode,
                 struct writeback_control *wbc)
{
    int ret;
    struct v9fs_inode *v9inode;
    /*
     * send an fsync request to server irrespective of
     * wbc->sync_mode.
     */
    p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
    v9inode = V9FS_I(inode);
    if (!v9inode->writeback_fid)
        return 0;
    ret = p9_client_fsync(v9inode->writeback_fid, 0);
    if (ret < 0) {
        __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
        return ret;
    }
    return 0;
}

static const struct super_operations v9fs_super_ops = {
    .alloc_inode = v9fs_alloc_inode,
    .destroy_inode = v9fs_destroy_inode,
    .statfs = simple_statfs,
    .evict_inode = v9fs_evict_inode,
    .show_options = generic_show_options,
    .umount_begin = v9fs_umount_begin,
    .write_inode = v9fs_write_inode,
};

static const struct super_operations v9fs_super_ops_dotl = {
    .alloc_inode = v9fs_alloc_inode,
    .destroy_inode = v9fs_destroy_inode,
    .statfs = v9fs_statfs,
    .drop_inode = v9fs_drop_inode,
    .evict_inode = v9fs_evict_inode,
    .show_options = generic_show_options,
    .umount_begin = v9fs_umount_begin,
    .write_inode = v9fs_write_inode_dotl,
};

struct file_system_type v9fs_fs_type = {
    .name = "9p",
    .mount = v9fs_mount,
    .kill_sb = v9fs_kill_super,
    .owner = THIS_MODULE,
    .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT,
};