lustre/lib/simple.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2002, 2003 Cluster File Systems, Inc.
   5  *  Author: Peter Braam <braam@clusterfs.com>
   6  *  Aurhot: Andreas Dilger <adilger@clusterfs.com>
   7  *
   8  *   This file is part of Lustre, http://www.lustre.org.
   9  *
  10  *   Lustre is free software; you can redistribute it and/or
  11  *   modify it under the terms of version 2 of the GNU General Public
  12  *   License as published by the Free Software Foundation.
  13  *
  14  *   Lustre is distributed in the hope that it will be useful,
  15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *   GNU General Public License for more details.
  18  *
  19  *   You should have received a copy of the GNU General Public License
  20  *   along with Lustre; if not, write to the Free Software
  21  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  */
  23
  24 #define EXPORT_SYMTAB
  25
  26 #include <linux/version.h>
  27 #include <linux/fs.h>
  28 #include <asm/unistd.h>
  29
  30 #define DEBUG_SUBSYSTEM S_FILTER
  31
  32 #include <linux/obd_support.h>
  33 #include <linux/obd.h>
  34 #include <linux/lustre_mds.h>
  35 #include <linux/lustre_lib.h>
  36 #include <linux/lustre_net.h>
  37
  38 #ifdef OBD_CTXT_DEBUG
  39 /* Debugging check only needed during development */
  40 #define ASSERT_CTXT_MAGIC(magic) LASSERT((magic) == OBD_RUN_CTXT_MAGIC)
  41 #define ASSERT_NOT_KERNEL_CTXT(msg) LASSERT(!segment_eq(get_fs(), get_ds()))
  42 #define ASSERT_KERNEL_CTXT(msg) LASSERT(segment_eq(get_fs(), get_ds()))
  43 #else
  44 #define ASSERT_CTXT_MAGIC(magic) do {} while(0)
  45 #define ASSERT_NOT_KERNEL_CTXT(msg) do {} while(0)
  46 #define ASSERT_KERNEL_CTXT(msg) do {} while(0)
  47 #endif
  48
  49 /* push / pop to root of obd store */
  50 void push_ctxt(struct obd_run_ctxt *save, struct obd_run_ctxt *new_ctx,
  51                struct obd_ucred *uc)
  52 {
  53         //ASSERT_NOT_KERNEL_CTXT("already in kernel context!\n");
  54         ASSERT_CTXT_MAGIC(new_ctx->magic);
  55         OBD_SET_CTXT_MAGIC(save);
  56
  57         /*
  58         CDEBUG(D_INFO, "== push %p->%p == cur fs %p pwd %p (%*s), pwdmnt %p\n",
  59                save, current, current->fs, current->fs->pwd,
  60                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
  61                current->fs->pwdmnt);
  62         */
  63
  64         save->fs = get_fs();
  65         LASSERT(atomic_read(&current->fs->pwd->d_count));
  66         LASSERT(atomic_read(&new_ctx->pwd->d_count));
  67         save->pwd = dget(current->fs->pwd);
  68         save->pwdmnt = mntget(current->fs->pwdmnt);
  69
  70         LASSERT(save->pwd);
  71         LASSERT(save->pwdmnt);
  72         LASSERT(new_ctx->pwd);
  73         LASSERT(new_ctx->pwdmnt);
  74
  75         if (uc) {
  76                 save->fsuid = current->fsuid;
  77                 save->fsgid = current->fsgid;
  78                 save->cap = current->cap_effective;
  79
  80                 current->fsuid = uc->ouc_fsuid;
  81                 current->fsgid = uc->ouc_fsgid;
  82                 current->cap_effective = uc->ouc_cap;
  83                 if (uc->ouc_suppgid != -1)
  84                         current->groups[current->ngroups++] = uc->ouc_suppgid;
  85         }
  86         set_fs(new_ctx->fs);
  87         set_fs_pwd(current->fs, new_ctx->pwdmnt, new_ctx->pwd);
  88
  89         /*
  90         CDEBUG(D_INFO, "== push %p==%p == cur fs %p pwd %p (%*s), pwdmnt %p\n",
  91                new_ctx, current, current->fs, current->fs->pwd,
  92                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
  93                current->fs->pwdmnt);
  94         */
  95 }
  96
  97 void pop_ctxt(struct obd_run_ctxt *saved, struct obd_run_ctxt *new_ctx,
  98               struct obd_ucred *uc)
  99 {
 100         //printk("pc0");
 101         ASSERT_CTXT_MAGIC(saved->magic);
 102         //printk("pc1");
 103         ASSERT_KERNEL_CTXT("popping non-kernel context!\n");
 104
 105         /*
 106         CDEBUG(D_INFO, " == pop  %p==%p == cur %p pwd %p (%*s), pwdmnt %p\n",
 107                new_ctx, current, current->fs, current->fs->pwd,
 108                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
 109                current->fs->pwdmnt);
 110         */
 111
 112         LASSERT(current->fs->pwd == new_ctx->pwd);
 113         LASSERT(current->fs->pwdmnt == new_ctx->pwdmnt);
 114
 115         //printk("pc2");
 116         set_fs(saved->fs);
 117         //printk("pc3\n");
 118         set_fs_pwd(current->fs, saved->pwdmnt, saved->pwd);
 119         //printk("pc4");
 120
 121         dput(saved->pwd);
 122         //printk("pc5");
 123         mntput(saved->pwdmnt);
 124         //printk("pc6\n");
 125         if (uc) {
 126                 current->fsuid = saved->fsuid;
 127                 current->fsgid = saved->fsgid;
 128                 current->cap_effective = saved->cap;
 129
 130                 if (uc->ouc_suppgid != -1)
 131                         current->ngroups--;
 132         }
 133
 134         /*
 135         CDEBUG(D_INFO, "== pop  %p->%p == cur fs %p pwd %p (%*s), pwdmnt %p\n",
 136                saved, current, current->fs, current->fs->pwd,
 137                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
 138                current->fs->pwdmnt);
 139         */
 140 }
 141
 142 /* utility to make a file */
 143 struct dentry *simple_mknod(struct dentry *dir, char *name, int mode)
 144 {
 145         struct dentry *dchild;
 146         int err = 0;
 147         ENTRY;
 148
 149         ASSERT_KERNEL_CTXT("kernel doing mknod outside kernel context\n");
 150         CDEBUG(D_INODE, "creating file %*s\n", (int)strlen(name), name);
 151
 152         dchild = lookup_one_len(name, dir, strlen(name));
 153         if (IS_ERR(dchild))
 154                 GOTO(out_up, dchild);
 155
 156         if (dchild->d_inode) {
 157                 if ((dchild->d_inode->i_mode & S_IFMT) != S_IFREG)
 158                         GOTO(out_err, err = -EEXIST);
 159
 160                 GOTO(out_up, dchild);
 161         }
 162
 163         err = vfs_create(dir->d_inode, dchild, (mode & ~S_IFMT) | S_IFREG);
 164         if (err)
 165                 GOTO(out_err, err);
 166
 167         RETURN(dchild);
 168
 169 out_err:
 170         dput(dchild);
 171         dchild = ERR_PTR(err);
 172 out_up:
 173         return dchild;
 174 }
 175
 176 /* utility to make a directory */
 177 struct dentry *simple_mkdir(struct dentry *dir, char *name, int mode)
 178 {
 179         struct dentry *dchild;
 180         int err = 0;
 181         ENTRY;
 182
 183         ASSERT_KERNEL_CTXT("kernel doing mkdir outside kernel context\n");
 184         CDEBUG(D_INODE, "creating directory %*s\n", (int)strlen(name), name);
 185         dchild = lookup_one_len(name, dir, strlen(name));
 186         if (IS_ERR(dchild))
 187                 GOTO(out_up, dchild);
 188
 189         if (dchild->d_inode) {
 190                 if (!S_ISDIR(dchild->d_inode->i_mode))
 191                         GOTO(out_err, err = -ENOTDIR);
 192
 193                 GOTO(out_up, dchild);
 194         }
 195
 196         err = vfs_mkdir(dir->d_inode, dchild, mode);
 197         if (err)
 198                 GOTO(out_err, err);
 199
 200         RETURN(dchild);
 201
 202 out_err:
 203         dput(dchild);
 204         dchild = ERR_PTR(err);
 205 out_up:
 206         return dchild;
 207 }
 208
 209 /*
 210  * Read a file from within kernel context.  Prior to calling this
 211  * function we should already have done a push_ctxt().
 212  */
 213 int lustre_fread(struct file *file, char *str, int len, loff_t *off)
 214 {
 215         ASSERT_KERNEL_CTXT("kernel doing read outside kernel context\n");
 216         if (!file || !file->f_op || !file->f_op->read || !off)
 217                 RETURN(-ENOSYS);
 218
 219         return file->f_op->read(file, str, len, off);
 220 }
 221
 222 /*
 223  * Write a file from within kernel context.  Prior to calling this
 224  * function we should already have done a push_ctxt().
 225  */
 226 int lustre_fwrite(struct file *file, const char *str, int len, loff_t *off)
 227 {
 228         ENTRY;
 229         ASSERT_KERNEL_CTXT("kernel doing write outside kernel context\n");
 230         if (!file)
 231                 RETURN(-ENOENT);
 232         if (!file->f_op)
 233                 RETURN(-ENOSYS);
 234         if (!off)
 235                 RETURN(-EINVAL);
 236
 237         if (!file->f_op->write)
 238                 RETURN(-EROFS);
 239
 240         RETURN(file->f_op->write(file, str, len, off));
 241 }
 242
 243 /*
 244  * Sync a file from within kernel context.  Prior to calling this
 245  * function we should already have done a push_ctxt().
 246  */
 247 int lustre_fsync(struct file *file)
 248 {
 249         ENTRY;
 250         ASSERT_KERNEL_CTXT("kernel doing sync outside kernel context\n");
 251         if (!file || !file->f_op || !file->f_op->fsync)
 252                 RETURN(-ENOSYS);
 253
 254         RETURN(file->f_op->fsync(file, file->f_dentry, 0));
 255 }