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/slab.h>
  21 #include <linux/mempool.h>
  22
  23 #include "netfs.h"
  24
  25 static int pohmelfs_send_lock_trans(struct pohmelfs_inode *pi,
  26                 u64 id, u64 start, u32 size, int type)
  27 {
  28         struct inode *inode = &pi->vfs_inode;
  29         struct pohmelfs_sb *psb = POHMELFS_SB(inode->i_sb);
  30         struct netfs_trans *t;
  31         struct netfs_cmd *cmd;
  32         int path_len, err;
  33         void *data;
  34         struct netfs_lock *l;
  35         int isize = (type & POHMELFS_LOCK_GRAB) ? 0 : sizeof(struct netfs_inode_info);
  36
  37         err = pohmelfs_path_length(pi);
  38         if (err < 0)
  39                 goto err_out_exit;
  40
  41         path_len = err;
  42
  43         err = -ENOMEM;
  44         t = netfs_trans_alloc(psb, path_len + sizeof(struct netfs_lock) + isize,
  45                         NETFS_TRANS_SINGLE_DST, 0);
  46         if (!t)
  47                 goto err_out_exit;
  48
  49         cmd = netfs_trans_current(t);
  50         data = cmd + 1;
  51
  52         err = pohmelfs_construct_path_string(pi, data, path_len);
  53         if (err < 0)
  54                 goto err_out_free;
  55         path_len = err;
  56
  57         l = data + path_len;
  58
  59         l->start = start;
  60         l->size = size;
  61         l->type = type;
  62         l->ino = pi->ino;
  63
  64         cmd->cmd = NETFS_LOCK;
  65         cmd->start = 0;
  66         cmd->id = id;
  67         cmd->size = sizeof(struct netfs_lock) + path_len + isize;
  68         cmd->ext = path_len;
  69         cmd->csize = 0;
  70
  71         netfs_convert_cmd(cmd);
  72         netfs_convert_lock(l);
  73
  74         if (isize) {
  75                 struct netfs_inode_info *info = (struct netfs_inode_info *)(l + 1);
  76
  77                 info->mode = inode->i_mode;
  78                 info->nlink = inode->i_nlink;
  79                 info->uid = inode->i_uid;
  80                 info->gid = inode->i_gid;
  81                 info->blocks = inode->i_blocks;
  82                 info->rdev = inode->i_rdev;
  83                 info->size = inode->i_size;
  84                 info->version = inode->i_version;
  85
  86                 netfs_convert_inode_info(info);
  87         }
  88
  89         netfs_trans_update(cmd, t, path_len + sizeof(struct netfs_lock) + isize);
  90
  91         return netfs_trans_finish(t, psb);
  92
  93 err_out_free:
  94         netfs_trans_free(t);
  95 err_out_exit:
  96         printk("%s: err: %d.\n", __func__, err);
  97         return err;
  98 }
  99
 100 int pohmelfs_data_lock(struct pohmelfs_inode *pi, u64 start, u32 size, int type)
 101 {
 102         struct pohmelfs_sb *psb = POHMELFS_SB(pi->vfs_inode.i_sb);
 103         struct pohmelfs_mcache *m;
 104         int err = -ENOMEM;
 105         struct iattr iattr;
 106         struct inode *inode = &pi->vfs_inode;
 107
 108         dprintk("%s: %p: ino: %llu, start: %llu, size: %u, "
 109                         "type: %d, locked as: %d, owned: %d.\n",
 110                         __func__, &pi->vfs_inode, pi->ino,
 111                         start, size, type, pi->lock_type,
 112                         !!test_bit(NETFS_INODE_OWNED, &pi->state));
 113
 114         if (!pohmelfs_need_lock(pi, type))
 115                 return 0;
 116
 117         m = pohmelfs_mcache_alloc(psb, start, size, NULL);
 118         if (IS_ERR(m))
 119                 return PTR_ERR(m);
 120
 121         err = pohmelfs_send_lock_trans(pi, m->gen, start, size,
 122                         type | POHMELFS_LOCK_GRAB);
 123         if (err)
 124                 goto err_out_put;
 125
 126         err = wait_for_completion_timeout(&m->complete, psb->mcache_timeout);
 127         if (err)
 128                 err = m->err;
 129         else
 130                 err = -ETIMEDOUT;
 131
 132         if (err) {
 133                 printk("%s: %p: ino: %llu, mgen: %llu, start: %llu, size: %u, err: %d.\n",
 134                         __func__, &pi->vfs_inode, pi->ino, m->gen, start, size, err);
 135         }
 136
 137         if (err && (err != -ENOENT))
 138                 goto err_out_put;
 139
 140         if (!err) {
 141                 netfs_convert_inode_info(&m->info);
 142
 143                 iattr.ia_valid = ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_SIZE | ATTR_ATIME;
 144                 iattr.ia_mode = m->info.mode;
 145                 iattr.ia_uid = m->info.uid;
 146                 iattr.ia_gid = m->info.gid;
 147                 iattr.ia_size = m->info.size;
 148                 iattr.ia_atime = CURRENT_TIME;
 149
 150                 dprintk("%s: %p: ino: %llu, mgen: %llu, start: %llu, isize: %llu -> %llu.\n",
 151                         __func__, &pi->vfs_inode, pi->ino, m->gen, start, inode->i_size, m->info.size);
 152
 153                 err = pohmelfs_setattr_raw(inode, &iattr);
 154                 if (!err) {
 155                         struct dentry *dentry = d_find_alias(inode);
 156                         if (dentry) {
 157                                 fsnotify_change(dentry, iattr.ia_valid);
 158                                 dput(dentry);
 159                         }
 160                 }
 161         }
 162
 163         pi->lock_type = type;
 164         set_bit(NETFS_INODE_OWNED, &pi->state);
 165
 166         pohmelfs_mcache_put(psb, m);
 167
 168         return 0;
 169
 170 err_out_put:
 171         pohmelfs_mcache_put(psb, m);
 172         return err;
 173 }
 174
 175 int pohmelfs_data_unlock(struct pohmelfs_inode *pi, u64 start, u32 size, int type)
 176 {
 177         dprintk("%s: %p: ino: %llu, start: %llu, size: %u, type: %d.\n",
 178                         __func__, &pi->vfs_inode, pi->ino, start, size, type);
 179         pi->lock_type = 0;
 180         clear_bit(NETFS_INODE_REMOTE_DIR_SYNCED, &pi->state);
 181         clear_bit(NETFS_INODE_OWNED, &pi->state);
 182         return pohmelfs_send_lock_trans(pi, pi->ino, start, size, type);
 183 }