drivers/staging/pohmelfs/lock.c

   1 /*
   2  * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
   3  * All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/backing-dev.h>
  18 #include <linux/fs.h>
  19 #include <linux/fsnotify.h>
  20 #include <linux/mempool.h>
  21
  22 #include "netfs.h"
  23
  24 static int pohmelfs_send_lock_trans(struct pohmelfs_inode *pi,
  25                 u64 id, u64 start, u32 size, int type)
  26 {
  27         struct inode *inode = &pi->vfs_inode;
  28         struct pohmelfs_sb *psb = POHMELFS_SB(inode->i_sb);
  29         struct netfs_trans *t;
  30         struct netfs_cmd *cmd;
  31         int path_len, err;
  32         void *data;
  33         struct netfs_lock *l;
  34         int isize = (type & POHMELFS_LOCK_GRAB) ? 0 : sizeof(struct netfs_inode_info);
  35
  36         err = pohmelfs_path_length(pi);
  37         if (err < 0)
  38                 goto err_out_exit;
  39
  40         path_len = err;
  41
  42         err = -ENOMEM;
  43         t = netfs_trans_alloc(psb, path_len + sizeof(struct netfs_lock) + isize,
  44                         NETFS_TRANS_SINGLE_DST, 0);
  45         if (!t)
  46                 goto err_out_exit;
  47
  48         cmd = netfs_trans_current(t);
  49         data = cmd + 1;
  50
  51         err = pohmelfs_construct_path_string(pi, data, path_len);
  52         if (err < 0)
  53                 goto err_out_free;
  54         path_len = err;
  55
  56         l = data + path_len;
  57
  58         l->start = start;
  59         l->size = size;
  60         l->type = type;
  61         l->ino = pi->ino;
  62
  63         cmd->cmd = NETFS_LOCK;
  64         cmd->start = 0;
  65         cmd->id = id;
  66         cmd->size = sizeof(struct netfs_lock) + path_len + isize;
  67         cmd->ext = path_len;
  68         cmd->csize = 0;
  69
  70         netfs_convert_cmd(cmd);
  71         netfs_convert_lock(l);
  72
  73         if (isize) {
  74                 struct netfs_inode_info *info = (struct netfs_inode_info *)(l + 1);
  75
  76                 info->mode = inode->i_mode;
  77                 info->nlink = inode->i_nlink;
  78                 info->uid = inode->i_uid;
  79                 info->gid = inode->i_gid;
  80                 info->blocks = inode->i_blocks;
  81                 info->rdev = inode->i_rdev;
  82                 info->size = inode->i_size;
  83                 info->version = inode->i_version;
  84
  85                 netfs_convert_inode_info(info);
  86         }
  87
  88         netfs_trans_update(cmd, t, path_len + sizeof(struct netfs_lock) + isize);
  89
  90         return netfs_trans_finish(t, psb);
  91
  92 err_out_free:
  93         netfs_trans_free(t);
  94 err_out_exit:
  95         printk("%s: err: %d.\n", __func__, err);
  96         return err;
  97 }
  98
  99 int pohmelfs_data_lock(struct pohmelfs_inode *pi, u64 start, u32 size, int type)
 100 {
 101         struct pohmelfs_sb *psb = POHMELFS_SB(pi->vfs_inode.i_sb);
 102         struct pohmelfs_mcache *m;
 103         int err = -ENOMEM;
 104         struct iattr iattr;
 105         struct inode *inode = &pi->vfs_inode;
 106
 107         dprintk("%s: %p: ino: %llu, start: %llu, size: %u, "
 108                         "type: %d, locked as: %d, owned: %d.\n",
 109                         __func__, &pi->vfs_inode, pi->ino,
 110                         start, size, type, pi->lock_type,
 111                         !!test_bit(NETFS_INODE_OWNED, &pi->state));
 112
 113         if (!pohmelfs_need_lock(pi, type))
 114                 return 0;
 115
 116         m = pohmelfs_mcache_alloc(psb, start, size, NULL);
 117         if (IS_ERR(m))
 118                 return PTR_ERR(m);
 119
 120         err = pohmelfs_send_lock_trans(pi, m->gen, start, size,
 121                         type | POHMELFS_LOCK_GRAB);
 122         if (err)
 123                 goto err_out_put;
 124
 125         err = wait_for_completion_timeout(&m->complete, psb->mcache_timeout);
 126         if (err)
 127                 err = m->err;
 128         else
 129                 err = -ETIMEDOUT;
 130
 131         if (err) {
 132                 printk("%s: %p: ino: %llu, mgen: %llu, start: %llu, size: %u, err: %d.\n",
 133                         __func__, &pi->vfs_inode, pi->ino, m->gen, start, size, err);
 134         }
 135
 136         if (err && (err != -ENOENT))
 137                 goto err_out_put;
 138
 139         if (!err) {
 140                 netfs_convert_inode_info(&m->info);
 141
 142                 iattr.ia_valid = ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_SIZE | ATTR_ATIME;
 143                 iattr.ia_mode = m->info.mode;
 144                 iattr.ia_uid = m->info.uid;
 145                 iattr.ia_gid = m->info.gid;
 146                 iattr.ia_size = m->info.size;
 147                 iattr.ia_atime = CURRENT_TIME;
 148
 149                 dprintk("%s: %p: ino: %llu, mgen: %llu, start: %llu, isize: %llu -> %llu.\n",
 150                         __func__, &pi->vfs_inode, pi->ino, m->gen, start, inode->i_size, m->info.size);
 151
 152                 err = pohmelfs_setattr_raw(inode, &iattr);
 153                 if (!err) {
 154                         struct dentry *dentry = d_find_alias(inode);
 155                         if (dentry) {
 156                                 fsnotify_change(dentry, iattr.ia_valid);
 157                                 dput(dentry);
 158                         }
 159                 }
 160         }
 161
 162         pi->lock_type = type;
 163         set_bit(NETFS_INODE_OWNED, &pi->state);
 164
 165         pohmelfs_mcache_put(psb, m);
 166
 167         return 0;
 168
 169 err_out_put:
 170         pohmelfs_mcache_put(psb, m);
 171         return err;
 172 }
 173
 174 int pohmelfs_data_unlock(struct pohmelfs_inode *pi, u64 start, u32 size, int type)
 175 {
 176         dprintk("%s: %p: ino: %llu, start: %llu, size: %u, type: %d.\n",
 177                         __func__, &pi->vfs_inode, pi->ino, start, size, type);
 178         pi->lock_type = 0;
 179         clear_bit(NETFS_INODE_REMOTE_DIR_SYNCED, &pi->state);
 180         clear_bit(NETFS_INODE_OWNED, &pi->state);
 181         return pohmelfs_send_lock_trans(pi, pi->ino, start, size, type);
 182 }