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