lustre/lib/simple.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  lib/simple.c
   5  *
   6  * Copyright (C) 2002  Cluster File Systems, Inc.
   7  *
   8  * This code is issued under the GNU General Public License.
   9  * See the file COPYING in this distribution
  10  *
  11  * by Peter Braam <braam@clusterfs.com>
  12  * and Andreas Dilger <adilger@clusterfs.com>
  13  */
  14
  15 #define EXPORT_SYMTAB
  16
  17 #include <linux/version.h>
  18 #include <linux/fs.h>
  19 #include <asm/unistd.h>
  20
  21 #define DEBUG_SUBSYSTEM S_FILTER
  22
  23 #include <linux/obd_support.h>
  24 #include <linux/obd.h>
  25 #include <linux/lustre_mds.h>
  26 #include <linux/lustre_lib.h>
  27 #include <linux/lustre_net.h>
  28
  29 #ifdef OBD_CTXT_DEBUG
  30 /* Debugging check only needed during development */
  31 #define ASSERT_CTXT_MAGIC(magic) do { if ((magic) != OBD_RUN_CTXT_MAGIC) { \
  32                                 CERROR("bad ctxt magic\n"); LBUG(); } } while(0)
  33 #define ASSERT_NOT_KERNEL_CTXT(msg) do { if (segment_eq(get_fs(), get_ds())) { \
  34                                         CERROR(msg); LBUG(); } } while(0)
  35 #define ASSERT_KERNEL_CTXT(msg) do { if (!segment_eq(get_fs(), get_ds())) { \
  36                                         CERROR(msg); LBUG(); } } while(0)
  37 #else
  38 #define ASSERT_CTXT_MAGIC(magic) do {} while(0)
  39 #define ASSERT_NOT_KERNEL_CTXT(msg) do {} while(0)
  40 #define ASSERT_KERNEL_CTXT(msg) do {} while(0)
  41 #endif
  42
  43 /* push / pop to root of obd store */
  44 void push_ctxt(struct obd_run_ctxt *save, struct obd_run_ctxt *new_ctx,
  45                struct obd_ucred *uc)
  46 {
  47         //ASSERT_NOT_KERNEL_CTXT("already in kernel context!\n");
  48         ASSERT_CTXT_MAGIC(new_ctx->magic);
  49         OBD_SET_CTXT_MAGIC(save);
  50
  51         /*
  52         CDEBUG(D_INFO, "== push %p->%p == cur fs %p pwd %p (%*s), pwdmnt %p\n",
  53                save, current, current->fs, current->fs->pwd,
  54                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
  55                current->fs->pwdmnt);
  56         */
  57
  58         save->fs = get_fs();
  59         save->pwd = dget(current->fs->pwd);
  60         save->pwdmnt = mntget(current->fs->pwdmnt);
  61
  62         LASSERT(save->pwd);
  63         LASSERT(save->pwdmnt);
  64         LASSERT(new_ctx->pwd);
  65         LASSERT(new_ctx->pwdmnt);
  66
  67         if (uc) {
  68                 save->fsuid = current->fsuid;
  69                 save->fsgid = current->fsgid;
  70                 save->cap = current->cap_effective;
  71
  72                 current->fsuid = uc->ouc_fsuid;
  73                 current->fsgid = uc->ouc_fsgid;
  74                 current->cap_effective = uc->ouc_cap;
  75         }
  76         set_fs(new_ctx->fs);
  77         set_fs_pwd(current->fs, new_ctx->pwdmnt, new_ctx->pwd);
  78
  79         /*
  80         CDEBUG(D_INFO, "== push %p==%p == cur fs %p pwd %p (%*s), pwdmnt %p\n",
  81                new_ctx, current, current->fs, current->fs->pwd,
  82                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
  83                current->fs->pwdmnt);
  84         */
  85 }
  86
  87 void pop_ctxt(struct obd_run_ctxt *saved, struct obd_run_ctxt *new_ctx,
  88               struct obd_ucred *uc)
  89 {
  90         //printk("pc0");
  91         ASSERT_CTXT_MAGIC(saved->magic);
  92         //printk("pc1");
  93         ASSERT_KERNEL_CTXT("popping non-kernel context!\n");
  94
  95         /*
  96         CDEBUG(D_INFO, " == pop  %p==%p == cur %p pwd %p (%*s), pwdmnt %p\n",
  97                new_ctx, current, current->fs, current->fs->pwd,
  98                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
  99                current->fs->pwdmnt);
 100         */
 101
 102         LASSERT(current->fs->pwd == new_ctx->pwd);
 103         LASSERT(current->fs->pwdmnt == new_ctx->pwdmnt);
 104
 105         //printk("pc2");
 106         set_fs(saved->fs);
 107         //printk("pc3\n");
 108         set_fs_pwd(current->fs, saved->pwdmnt, saved->pwd);
 109         //printk("pc4");
 110
 111         dput(saved->pwd);
 112         //printk("pc5");
 113         mntput(saved->pwdmnt);
 114         //printk("pc6\n");
 115         if (uc) {
 116                 current->fsuid = saved->fsuid;
 117                 current->fsgid = saved->fsgid;
 118                 current->cap_effective = saved->cap;
 119         }
 120
 121         /*
 122         CDEBUG(D_INFO, "== pop  %p->%p == cur fs %p pwd %p (%*s), pwdmnt %p\n",
 123                saved, current, current->fs, current->fs->pwd,
 124                current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
 125                current->fs->pwdmnt);
 126         */
 127 }
 128
 129 /* utility to make a file */
 130 struct dentry *simple_mknod(struct dentry *dir, char *name, int mode)
 131 {
 132         struct dentry *dchild;
 133         int err = 0;
 134         ENTRY;
 135
 136         ASSERT_KERNEL_CTXT("kernel doing mknod outside kernel context\n");
 137         CDEBUG(D_INODE, "creating file %*s\n", (int)strlen(name), name);
 138
 139         down(&dir->d_inode->i_sem);
 140         dchild = lookup_one_len(name, dir, strlen(name));
 141         if (IS_ERR(dchild))
 142                 GOTO(out, PTR_ERR(dchild));
 143
 144         if (dchild->d_inode) {
 145                 if ((dchild->d_inode->i_mode & S_IFMT) != S_IFREG)
 146                         GOTO(out, err = -EEXIST);
 147
 148                 GOTO(out, dchild);
 149         }
 150
 151         err = vfs_create(dir->d_inode, dchild, (mode & ~S_IFMT) | S_IFREG);
 152         EXIT;
 153 out:
 154         up(&dir->d_inode->i_sem);
 155         if (err) {
 156                 dput(dchild);
 157                 RETURN(ERR_PTR(err));
 158         }
 159
 160         RETURN(dchild);
 161 }
 162
 163 /* utility to make a directory */
 164 struct dentry *simple_mkdir(struct dentry *dir, char *name, int mode)
 165 {
 166         struct dentry *dchild;
 167         int err = 0;
 168         ENTRY;
 169
 170         ASSERT_KERNEL_CTXT("kernel doing mkdir outside kernel context\n");
 171         CDEBUG(D_INODE, "creating directory %*s\n", (int)strlen(name), name);
 172         down(&dir->d_inode->i_sem);
 173         dchild = lookup_one_len(name, dir, strlen(name));
 174         if (IS_ERR(dchild))
 175                 GOTO(out, PTR_ERR(dchild));
 176
 177         if (dchild->d_inode) {
 178                 if (!S_ISDIR(dchild->d_inode->i_mode))
 179                         GOTO(out, err = -ENOTDIR);
 180
 181                 GOTO(out, dchild);
 182         }
 183
 184         err = vfs_mkdir(dir->d_inode, dchild, mode);
 185         EXIT;
 186 out:
 187         up(&dir->d_inode->i_sem);
 188         if (err) {
 189                 dput(dchild);
 190                 RETURN(ERR_PTR(err));
 191         }
 192
 193         RETURN(dchild);
 194 }
 195
 196 /*
 197  * Read a file from within kernel context.  Prior to calling this
 198  * function we should already have done a push_ctxt().
 199  */
 200 int lustre_fread(struct file *file, char *str, int len, loff_t *off)
 201 {
 202         ASSERT_KERNEL_CTXT("kernel doing read outside kernel context\n");
 203         if (!file || !file->f_op || !file->f_op->read || !off)
 204                 RETURN(-ENOSYS);
 205
 206         return file->f_op->read(file, str, len, off);
 207 }
 208
 209 /*
 210  * Write a file from within kernel context.  Prior to calling this
 211  * function we should already have done a push_ctxt().
 212  */
 213 int lustre_fwrite(struct file *file, const char *str, int len, loff_t *off)
 214 {
 215         ASSERT_KERNEL_CTXT("kernel doing write outside kernel context\n");
 216         if (!file || !file->f_op || !off)
 217                 RETURN(-ENOSYS);
 218
 219         if (!file->f_op->write)
 220                 RETURN(-EROFS);
 221
 222         return file->f_op->write(file, str, len, off);
 223 }
 224
 225 /*
 226  * Sync a file from within kernel context.  Prior to calling this
 227  * function we should already have done a push_ctxt().
 228  */
 229 int lustre_fsync(struct file *file)
 230 {
 231         ASSERT_KERNEL_CTXT("kernel doing sync outside kernel context\n");
 232         if (!file || !file->f_op || !file->f_op->fsync)
 233                 RETURN(-ENOSYS);
 234
 235         return file->f_op->fsync(file, file->f_dentry, 0);
 236 }