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