fs/lockd/svcsubs.c

   1 /*
   2  * linux/fs/lockd/svcsubs.c
   3  *
   4  * Various support routines for the NLM server.
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/string.h>
  11 #include <linux/time.h>
  12 #include <linux/in.h>
  13 #include <linux/mutex.h>
  14 #include <linux/sunrpc/svc.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/nfsd/nfsfh.h>
  17 #include <linux/nfsd/export.h>
  18 #include <linux/lockd/lockd.h>
  19 #include <linux/lockd/share.h>
  20 #include <linux/lockd/sm_inter.h>
  21
  22 #define NLMDBG_FACILITY         NLMDBG_SVCSUBS
  23
  24
  25 /*
  26  * Global file hash table
  27  */
  28 #define FILE_HASH_BITS          5
  29 #define FILE_NRHASH             (1<<FILE_HASH_BITS)
  30 static struct nlm_file *        nlm_files[FILE_NRHASH];
  31 static DEFINE_MUTEX(nlm_file_mutex);
  32
  33 #ifdef NFSD_DEBUG
  34 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
  35 {
  36         u32 *fhp = (u32*)f->data;
  37
  38         /* print the first 32 bytes of the fh */
  39         dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
  40                 msg, fhp[0], fhp[1], fhp[2], fhp[3],
  41                 fhp[4], fhp[5], fhp[6], fhp[7]);
  42 }
  43
  44 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
  45 {
  46         struct inode *inode = file->f_file->f_dentry->d_inode;
  47
  48         dprintk("lockd: %s %s/%ld\n",
  49                 msg, inode->i_sb->s_id, inode->i_ino);
  50 }
  51 #else
  52 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
  53 {
  54         return;
  55 }
  56
  57 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
  58 {
  59         return;
  60 }
  61 #endif
  62
  63 static inline unsigned int file_hash(struct nfs_fh *f)
  64 {
  65         unsigned int tmp=0;
  66         int i;
  67         for (i=0; i<NFS2_FHSIZE;i++)
  68                 tmp += f->data[i];
  69         return tmp & (FILE_NRHASH - 1);
  70 }
  71
  72 /*
  73  * Lookup file info. If it doesn't exist, create a file info struct
  74  * and open a (VFS) file for the given inode.
  75  *
  76  * FIXME:
  77  * Note that we open the file O_RDONLY even when creating write locks.
  78  * This is not quite right, but for now, we assume the client performs
  79  * the proper R/W checking.
  80  */
  81 u32
  82 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
  83                                         struct nfs_fh *f)
  84 {
  85         struct nlm_file *file;
  86         unsigned int    hash;
  87         u32             nfserr;
  88
  89         nlm_debug_print_fh("nlm_file_lookup", f);
  90
  91         hash = file_hash(f);
  92
  93         /* Lock file table */
  94         mutex_lock(&nlm_file_mutex);
  95
  96         for (file = nlm_files[hash]; file; file = file->f_next)
  97                 if (!nfs_compare_fh(&file->f_handle, f))
  98                         goto found;
  99
 100         nlm_debug_print_fh("creating file for", f);
 101
 102         nfserr = nlm_lck_denied_nolocks;
 103         file = kzalloc(sizeof(*file), GFP_KERNEL);
 104         if (!file)
 105                 goto out_unlock;
 106
 107         memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
 108         file->f_hash = hash;
 109         init_MUTEX(&file->f_sema);
 110
 111         /* Open the file. Note that this must not sleep for too long, else
 112          * we would lock up lockd:-) So no NFS re-exports, folks.
 113          *
 114          * We have to make sure we have the right credential to open
 115          * the file.
 116          */
 117         if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
 118                 dprintk("lockd: open failed (nfserr %d)\n", ntohl(nfserr));
 119                 goto out_free;
 120         }
 121
 122         file->f_next = nlm_files[hash];
 123         nlm_files[hash] = file;
 124
 125 found:
 126         dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
 127         *result = file;
 128         file->f_count++;
 129         nfserr = 0;
 130
 131 out_unlock:
 132         mutex_unlock(&nlm_file_mutex);
 133         return nfserr;
 134
 135 out_free:
 136         kfree(file);
 137 #ifdef CONFIG_LOCKD_V4
 138         if (nfserr == 1)
 139                 nfserr = nlm4_stale_fh;
 140         else
 141 #endif
 142         nfserr = nlm_lck_denied;
 143         goto out_unlock;
 144 }
 145
 146 /*
 147  * Delete a file after having released all locks, blocks and shares
 148  */
 149 static inline void
 150 nlm_delete_file(struct nlm_file *file)
 151 {
 152         struct nlm_file **fp, *f;
 153
 154         nlm_debug_print_file("closing file", file);
 155
 156         fp = nlm_files + file->f_hash;
 157         while ((f = *fp) != NULL) {
 158                 if (f == file) {
 159                         *fp = file->f_next;
 160                         nlmsvc_ops->fclose(file->f_file);
 161                         kfree(file);
 162                         return;
 163                 }
 164                 fp = &f->f_next;
 165         }
 166
 167         printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
 168 }
 169
 170 /*
 171  * Loop over all locks on the given file and perform the specified
 172  * action.
 173  */
 174 static int
 175 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
 176 {
 177         struct inode     *inode = nlmsvc_file_inode(file);
 178         struct file_lock *fl;
 179         struct nlm_host  *lockhost;
 180
 181 again:
 182         file->f_locks = 0;
 183         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 184                 if (fl->fl_lmops != &nlmsvc_lock_operations)
 185                         continue;
 186
 187                 /* update current lock count */
 188                 file->f_locks++;
 189                 lockhost = (struct nlm_host *) fl->fl_owner;
 190                 if (action == NLM_ACT_MARK)
 191                         lockhost->h_inuse = 1;
 192                 else if (action == NLM_ACT_CHECK)
 193                         return 1;
 194                 else if (action == NLM_ACT_UNLOCK) {
 195                         struct file_lock lock = *fl;
 196
 197                         if (host && lockhost != host)
 198                                 continue;
 199
 200                         lock.fl_type  = F_UNLCK;
 201                         lock.fl_start = 0;
 202                         lock.fl_end   = OFFSET_MAX;
 203                         if (posix_lock_file(file->f_file, &lock) < 0) {
 204                                 printk("lockd: unlock failure in %s:%d\n",
 205                                                 __FILE__, __LINE__);
 206                                 return 1;
 207                         }
 208                         goto again;
 209                 }
 210         }
 211
 212         return 0;
 213 }
 214
 215 /*
 216  * Operate on a single file
 217  */
 218 static inline int
 219 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
 220 {
 221         if (action == NLM_ACT_CHECK) {
 222                 /* Fast path for mark and sweep garbage collection */
 223                 if (file->f_count || file->f_blocks || file->f_shares)
 224                         return 1;
 225         } else {
 226                 nlmsvc_traverse_blocks(host, file, action);
 227                 nlmsvc_traverse_shares(host, file, action);
 228         }
 229         return nlm_traverse_locks(host, file, action);
 230 }
 231
 232 /*
 233  * Loop over all files in the file table.
 234  */
 235 static int
 236 nlm_traverse_files(struct nlm_host *host, int action)
 237 {
 238         struct nlm_file *file, **fp;
 239         int i, ret = 0;
 240
 241         mutex_lock(&nlm_file_mutex);
 242         for (i = 0; i < FILE_NRHASH; i++) {
 243                 fp = nlm_files + i;
 244                 while ((file = *fp) != NULL) {
 245                         file->f_count++;
 246                         mutex_unlock(&nlm_file_mutex);
 247
 248                         /* Traverse locks, blocks and shares of this file
 249                          * and update file->f_locks count */
 250                         if (nlm_inspect_file(host, file, action))
 251                                 ret = 1;
 252
 253                         mutex_lock(&nlm_file_mutex);
 254                         file->f_count--;
 255                         /* No more references to this file. Let go of it. */
 256                         if (!file->f_blocks && !file->f_locks
 257                          && !file->f_shares && !file->f_count) {
 258                                 *fp = file->f_next;
 259                                 nlmsvc_ops->fclose(file->f_file);
 260                                 kfree(file);
 261                         } else {
 262                                 fp = &file->f_next;
 263                         }
 264                 }
 265         }
 266         mutex_unlock(&nlm_file_mutex);
 267         return ret;
 268 }
 269
 270 /*
 271  * Release file. If there are no more remote locks on this file,
 272  * close it and free the handle.
 273  *
 274  * Note that we can't do proper reference counting without major
 275  * contortions because the code in fs/locks.c creates, deletes and
 276  * splits locks without notification. Our only way is to walk the
 277  * entire lock list each time we remove a lock.
 278  */
 279 void
 280 nlm_release_file(struct nlm_file *file)
 281 {
 282         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 283                                 file, file->f_count);
 284
 285         /* Lock file table */
 286         mutex_lock(&nlm_file_mutex);
 287
 288         /* If there are no more locks etc, delete the file */
 289         if(--file->f_count == 0) {
 290                 if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
 291                         nlm_delete_file(file);
 292         }
 293
 294         mutex_unlock(&nlm_file_mutex);
 295 }
 296
 297 /*
 298  * Mark all hosts that still hold resources
 299  */
 300 void
 301 nlmsvc_mark_resources(void)
 302 {
 303         dprintk("lockd: nlmsvc_mark_resources\n");
 304
 305         nlm_traverse_files(NULL, NLM_ACT_MARK);
 306 }
 307
 308 /*
 309  * Release all resources held by the given client
 310  */
 311 void
 312 nlmsvc_free_host_resources(struct nlm_host *host)
 313 {
 314         dprintk("lockd: nlmsvc_free_host_resources\n");
 315
 316         if (nlm_traverse_files(host, NLM_ACT_UNLOCK))
 317                 printk(KERN_WARNING
 318                         "lockd: couldn't remove all locks held by %s",
 319                         host->h_name);
 320 }
 321
 322 /*
 323  * delete all hosts structs for clients
 324  */
 325 void
 326 nlmsvc_invalidate_all(void)
 327 {
 328         struct nlm_host *host;
 329         while ((host = nlm_find_client()) != NULL) {
 330                 nlmsvc_free_host_resources(host);
 331                 host->h_expires = 0;
 332                 host->h_killed = 1;
 333                 nlm_release_host(host);
 334         }
 335 }