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 = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL);
 104         if (!file)
 105                 goto out_unlock;
 106
 107         memset(file, 0, sizeof(*file));
 108         memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
 109         file->f_hash = hash;
 110         init_MUTEX(&file->f_sema);
 111
 112         /* Open the file. Note that this must not sleep for too long, else
 113          * we would lock up lockd:-) So no NFS re-exports, folks.
 114          *
 115          * We have to make sure we have the right credential to open
 116          * the file.
 117          */
 118         if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
 119                 dprintk("lockd: open failed (nfserr %d)\n", ntohl(nfserr));
 120                 goto out_free;
 121         }
 122
 123         file->f_next = nlm_files[hash];
 124         nlm_files[hash] = file;
 125
 126 found:
 127         dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
 128         *result = file;
 129         file->f_count++;
 130         nfserr = 0;
 131
 132 out_unlock:
 133         mutex_unlock(&nlm_file_mutex);
 134         return nfserr;
 135
 136 out_free:
 137         kfree(file);
 138 #ifdef CONFIG_LOCKD_V4
 139         if (nfserr == 1)
 140                 nfserr = nlm4_stale_fh;
 141         else
 142 #endif
 143         nfserr = nlm_lck_denied;
 144         goto out_unlock;
 145 }
 146
 147 /*
 148  * Delete a file after having released all locks, blocks and shares
 149  */
 150 static inline void
 151 nlm_delete_file(struct nlm_file *file)
 152 {
 153         struct nlm_file **fp, *f;
 154
 155         nlm_debug_print_file("closing file", file);
 156
 157         fp = nlm_files + file->f_hash;
 158         while ((f = *fp) != NULL) {
 159                 if (f == file) {
 160                         *fp = file->f_next;
 161                         nlmsvc_ops->fclose(file->f_file);
 162                         kfree(file);
 163                         return;
 164                 }
 165                 fp = &f->f_next;
 166         }
 167
 168         printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
 169 }
 170
 171 /*
 172  * Loop over all locks on the given file and perform the specified
 173  * action.
 174  */
 175 static int
 176 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
 177 {
 178         struct inode     *inode = nlmsvc_file_inode(file);
 179         struct file_lock *fl;
 180         struct nlm_host  *lockhost;
 181
 182 again:
 183         file->f_locks = 0;
 184         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 185                 if (fl->fl_lmops != &nlmsvc_lock_operations)
 186                         continue;
 187
 188                 /* update current lock count */
 189                 file->f_locks++;
 190                 lockhost = (struct nlm_host *) fl->fl_owner;
 191                 if (action == NLM_ACT_MARK)
 192                         lockhost->h_inuse = 1;
 193                 else if (action == NLM_ACT_CHECK)
 194                         return 1;
 195                 else if (action == NLM_ACT_UNLOCK) {
 196                         struct file_lock lock = *fl;
 197
 198                         if (host && lockhost != host)
 199                                 continue;
 200
 201                         lock.fl_type  = F_UNLCK;
 202                         lock.fl_start = 0;
 203                         lock.fl_end   = OFFSET_MAX;
 204                         if (posix_lock_file(file->f_file, &lock) < 0) {
 205                                 printk("lockd: unlock failure in %s:%d\n",
 206                                                 __FILE__, __LINE__);
 207                                 return 1;
 208                         }
 209                         goto again;
 210                 }
 211         }
 212
 213         return 0;
 214 }
 215
 216 /*
 217  * Operate on a single file
 218  */
 219 static inline int
 220 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
 221 {
 222         if (action == NLM_ACT_CHECK) {
 223                 /* Fast path for mark and sweep garbage collection */
 224                 if (file->f_count || file->f_blocks || file->f_shares)
 225                         return 1;
 226         } else {
 227                 nlmsvc_traverse_blocks(host, file, action);
 228                 nlmsvc_traverse_shares(host, file, action);
 229         }
 230         return nlm_traverse_locks(host, file, action);
 231 }
 232
 233 /*
 234  * Loop over all files in the file table.
 235  */
 236 static int
 237 nlm_traverse_files(struct nlm_host *host, int action)
 238 {
 239         struct nlm_file *file, **fp;
 240         int i, ret = 0;
 241
 242         mutex_lock(&nlm_file_mutex);
 243         for (i = 0; i < FILE_NRHASH; i++) {
 244                 fp = nlm_files + i;
 245                 while ((file = *fp) != NULL) {
 246                         file->f_count++;
 247                         mutex_unlock(&nlm_file_mutex);
 248
 249                         /* Traverse locks, blocks and shares of this file
 250                          * and update file->f_locks count */
 251                         if (nlm_inspect_file(host, file, action))
 252                                 ret = 1;
 253
 254                         mutex_lock(&nlm_file_mutex);
 255                         file->f_count--;
 256                         /* No more references to this file. Let go of it. */
 257                         if (!file->f_blocks && !file->f_locks
 258                          && !file->f_shares && !file->f_count) {
 259                                 *fp = file->f_next;
 260                                 nlmsvc_ops->fclose(file->f_file);
 261                                 kfree(file);
 262                         } else {
 263                                 fp = &file->f_next;
 264                         }
 265                 }
 266         }
 267         mutex_unlock(&nlm_file_mutex);
 268         return ret;
 269 }
 270
 271 /*
 272  * Release file. If there are no more remote locks on this file,
 273  * close it and free the handle.
 274  *
 275  * Note that we can't do proper reference counting without major
 276  * contortions because the code in fs/locks.c creates, deletes and
 277  * splits locks without notification. Our only way is to walk the
 278  * entire lock list each time we remove a lock.
 279  */
 280 void
 281 nlm_release_file(struct nlm_file *file)
 282 {
 283         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 284                                 file, file->f_count);
 285
 286         /* Lock file table */
 287         mutex_lock(&nlm_file_mutex);
 288
 289         /* If there are no more locks etc, delete the file */
 290         if(--file->f_count == 0) {
 291                 if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
 292                         nlm_delete_file(file);
 293         }
 294
 295         mutex_unlock(&nlm_file_mutex);
 296 }
 297
 298 /*
 299  * Mark all hosts that still hold resources
 300  */
 301 void
 302 nlmsvc_mark_resources(void)
 303 {
 304         dprintk("lockd: nlmsvc_mark_resources\n");
 305
 306         nlm_traverse_files(NULL, NLM_ACT_MARK);
 307 }
 308
 309 /*
 310  * Release all resources held by the given client
 311  */
 312 void
 313 nlmsvc_free_host_resources(struct nlm_host *host)
 314 {
 315         dprintk("lockd: nlmsvc_free_host_resources\n");
 316
 317         if (nlm_traverse_files(host, NLM_ACT_UNLOCK))
 318                 printk(KERN_WARNING
 319                         "lockd: couldn't remove all locks held by %s",
 320                         host->h_name);
 321 }
 322
 323 /*
 324  * delete all hosts structs for clients
 325  */
 326 void
 327 nlmsvc_invalidate_all(void)
 328 {
 329         struct nlm_host *host;
 330         while ((host = nlm_find_client()) != NULL) {
 331                 nlmsvc_free_host_resources(host);
 332                 host->h_expires = 0;
 333                 host->h_killed = 1;
 334                 nlm_release_host(host);
 335         }
 336 }