/*
   *  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 <ericvh@gmail.com>
   *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   *
   *  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;
  
  /**
   * v9fs_set_super - set the superblock
   * @s: super block
   * @data: file system specific data
   *
   */
  
  static int v9fs_set_super(struct super_block *s, void *data)
  {
  	s->s_fs_info = data;
  	return set_anon_super(s, data);
  }
  
  /**
   * v9fs_fill_super - populate superblock with info
   * @sb: superblock
   * @v9ses: session information
   * @flags: flags propagated from v9fs_mount()
   *
   */
  
  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);
  }
  
  /**
   * v9fs_mount - mount a superblock
   * @fs_type: file system type
   * @flags: mount flags
   * @dev_name: device name that was mounted
   * @data: mount options
   *
   */
  
  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, "
  ");
  
  	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 == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
  		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
  ");
  	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);
  }
  
  /**
   * v9fs_kill_super - Kill Superblock
   * @s: superblock
   *
   */
  
  static void v9fs_kill_super(struct super_block *s)
  {
  	struct v9fs_session_info *v9ses = s->s_fs_info;
  
  	p9_debug(P9_DEBUG_VFS, " %p
  ", 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
  ");
  }
  
  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 == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
  		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
  ", __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.
  	 */
  	v9inode = V9FS_I(inode);
  	p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p
  ",
  		 __func__, inode, v9inode->writeback_fid);
  	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,
  };
  MODULE_ALIAS_FS("9p");