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/sched.h>
  12 #include <linux/in.h>
  13 #include <linux/sunrpc/svc.h>
  14 #include <linux/sunrpc/clnt.h>
  15 #include <linux/nfsd/nfsfh.h>
  16 #include <linux/nfsd/export.h>
  17 #include <linux/lockd/lockd.h>
  18 #include <linux/lockd/share.h>
  19 #include <linux/lockd/sm_inter.h>
  20
  21 #define NLMDBG_FACILITY         NLMDBG_SVCSUBS
  22
  23
  24 /*
  25  * Global file hash table
  26  */
  27 #define FILE_NRHASH             32
  28 #define FILE_HASH_BITS          5
  29 static struct nlm_file *        nlm_files[FILE_NRHASH];
  30 static DECLARE_MUTEX(nlm_file_sema);
  31
  32 static unsigned int file_hash(dev_t dev, ino_t ino)
  33 {
  34         unsigned long tmp = (unsigned long) ino | (unsigned long) dev;
  35         tmp = tmp + (tmp >> FILE_HASH_BITS) + (tmp >> FILE_HASH_BITS*2);
  36         return tmp & (FILE_NRHASH - 1);
  37 }
  38
  39 /*
  40  * Lookup file info. If it doesn't exist, create a file info struct
  41  * and open a (VFS) file for the given inode.
  42  *
  43  * FIXME:
  44  * Note that we open the file O_RDONLY even when creating write locks.
  45  * This is not quite right, but for now, we assume the client performs
  46  * the proper R/W checking.
  47  */
  48 u32
  49 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
  50                                         struct nfs_fh *f)
  51 {
  52         struct knfs_fh  *fh = (struct knfs_fh *) f;
  53         struct nlm_file *file;
  54         unsigned int    hash;
  55         u32             nfserr;
  56
  57         dprintk("lockd: nlm_file_lookup(%s/%u)\n",
  58                 kdevname(u32_to_kdev_t(fh->fh_dev)), fh->fh_ino);
  59
  60         hash = file_hash(u32_to_kdev_t(fh->fh_dev), u32_to_ino_t(fh->fh_ino));
  61
  62         /* Lock file table */
  63         down(&nlm_file_sema);
  64
  65         for (file = nlm_files[hash]; file; file = file->f_next) {
  66                 if (file->f_handle.fh_dcookie == fh->fh_dcookie &&
  67                     !memcmp(&file->f_handle, fh, sizeof(*fh)))
  68                         goto found;
  69         }
  70
  71         dprintk("lockd: creating file for %s/%u\n",
  72                 kdevname(u32_to_kdev_t(fh->fh_dev)), fh->fh_ino);
  73         nfserr = nlm_lck_denied_nolocks;
  74         file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL);
  75         if (!file)
  76                 goto out_unlock;
  77
  78         memset(file, 0, sizeof(*file));
  79         file->f_handle = *fh;
  80         init_MUTEX(&file->f_sema);
  81
  82         /* Open the file. Note that this must not sleep for too long, else
  83          * we would lock up lockd:-) So no NFS re-exports, folks.
  84          *
  85          * We have to make sure we have the right credential to open
  86          * the file.
  87          */
  88         if ((nfserr = nlmsvc_ops->fopen(rqstp, fh, &file->f_file)) != 0) {
  89                 dprintk("lockd: open failed (nfserr %ld)\n", ntohl(nfserr));
  90                 goto out_free;
  91         }
  92
  93         file->f_next = nlm_files[hash];
  94         nlm_files[hash] = file;
  95
  96 found:
  97         dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
  98         *result = file;
  99         file->f_count++;
 100         nfserr = 0;
 101
 102 out_unlock:
 103         up(&nlm_file_sema);
 104         return nfserr;
 105
 106 out_free:
 107         kfree(file);
 108         nfserr = nlm_lck_denied;
 109         goto out_unlock;
 110 }
 111
 112 /*
 113  * Delete a file after having released all locks, blocks and shares
 114  */
 115 static inline void
 116 nlm_delete_file(struct nlm_file *file)
 117 {
 118         struct inode *inode = file->f_file.f_dentry->d_inode;
 119         struct nlm_file **fp, *f;
 120
 121         dprintk("lockd: closing file %s/%ld\n",
 122                 kdevname(inode->i_dev), inode->i_ino);
 123         fp = nlm_files + file_hash(inode->i_dev, inode->i_ino);
 124         while ((f = *fp) != NULL) {
 125                 if (f == file) {
 126                         *fp = file->f_next;
 127                         nlmsvc_ops->fclose(&file->f_file);
 128                         kfree(file);
 129                         return;
 130                 }
 131                 fp = &f->f_next;
 132         }
 133
 134         printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
 135 }
 136
 137 /*
 138  * Loop over all locks on the given file and perform the specified
 139  * action.
 140  */
 141 static int
 142 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
 143 {
 144         struct inode     *inode = nlmsvc_file_inode(file);
 145         struct file_lock *fl;
 146         struct nlm_host  *lockhost;
 147
 148 again:
 149         file->f_locks = 0;
 150         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 151                 if (!(fl->fl_flags & FL_LOCKD))
 152                         continue;
 153
 154                 /* update current lock count */
 155                 file->f_locks++;
 156                 lockhost = (struct nlm_host *) fl->fl_owner;
 157                 if (action == NLM_ACT_MARK)
 158                         lockhost->h_inuse = 1;
 159                 else if (action == NLM_ACT_CHECK)
 160                         return 1;
 161                 else if (action == NLM_ACT_UNLOCK) {
 162                         struct file_lock lock = *fl;
 163
 164                         if (host && lockhost != host)
 165                                 continue;
 166
 167                         lock.fl_type  = F_UNLCK;
 168                         lock.fl_start = 0;
 169                         lock.fl_end   = NLM_OFFSET_MAX;
 170                         if (posix_lock_file(&file->f_file, &lock, 0) < 0) {
 171                                 printk("lockd: unlock failure in %s:%d\n",
 172                                                 __FILE__, __LINE__);
 173                                 return 1;
 174                         }
 175                         goto again;
 176                 }
 177         }
 178
 179         return 0;
 180 }
 181
 182 /*
 183  * Operate on a single file
 184  */
 185 static inline int
 186 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
 187 {
 188         if (action == NLM_ACT_CHECK) {
 189                 /* Fast path for mark and sweep garbage collection */
 190                 if (file->f_count || file->f_blocks || file->f_shares)
 191                         return 1;
 192         } else {
 193                 if (nlmsvc_traverse_blocks(host, file, action)
 194                  || nlmsvc_traverse_shares(host, file, action))
 195                         return 1;
 196         }
 197         return nlm_traverse_locks(host, file, action);
 198 }
 199
 200 /*
 201  * Loop over all files in the file table.
 202  */
 203 static int
 204 nlm_traverse_files(struct nlm_host *host, int action)
 205 {
 206         struct nlm_file *file, **fp;
 207         int             i;
 208
 209         down(&nlm_file_sema);
 210         for (i = 0; i < FILE_NRHASH; i++) {
 211                 fp = nlm_files + i;
 212                 while ((file = *fp) != NULL) {
 213                         /* Traverse locks, blocks and shares of this file
 214                          * and update file->f_locks count */
 215                         if (nlm_inspect_file(host, file, action)) {
 216                                 up(&nlm_file_sema);
 217                                 return 1;
 218                         }
 219
 220                         /* No more references to this file. Let go of it. */
 221                         if (!file->f_blocks && !file->f_locks
 222                          && !file->f_shares && !file->f_count) {
 223                                 *fp = file->f_next;
 224                                 nlmsvc_ops->fclose(&file->f_file);
 225                                 kfree(file);
 226                         } else {
 227                                 fp = &file->f_next;
 228                         }
 229                 }
 230         }
 231         up(&nlm_file_sema);
 232         return 0;
 233 }
 234
 235 /*
 236  * Release file. If there are no more remote locks on this file,
 237  * close it and free the handle.
 238  *
 239  * Note that we can't do proper reference counting without major
 240  * contortions because the code in fs/locks.c creates, deletes and
 241  * splits locks without notification. Our only way is to walk the
 242  * entire lock list each time we remove a lock.
 243  */
 244 void
 245 nlm_release_file(struct nlm_file *file)
 246 {
 247         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 248                                 file, file->f_count);
 249
 250         /* Lock file table */
 251         down(&nlm_file_sema);
 252
 253         /* If there are no more locks etc, delete the file */
 254         if(--file->f_count == 0) {
 255                 if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
 256                         nlm_delete_file(file);
 257         }
 258
 259         up(&nlm_file_sema);
 260 }
 261
 262 /*
 263  * Mark all hosts that still hold resources
 264  */
 265 void
 266 nlmsvc_mark_resources(void)
 267 {
 268         dprintk("lockd: nlmsvc_mark_resources\n");
 269
 270         nlm_traverse_files(NULL, NLM_ACT_MARK);
 271 }
 272
 273 /*
 274  * Release all resources held by the given client
 275  */
 276 void
 277 nlmsvc_free_host_resources(struct nlm_host *host)
 278 {
 279         dprintk("lockd: nlmsvc_free_host_resources\n");
 280
 281         if (nlm_traverse_files(host, NLM_ACT_UNLOCK))
 282                 printk(KERN_WARNING
 283                         "lockd: couldn't remove all locks held by %s",
 284                         host->h_name);
 285 }
 286
 287 /*
 288  * Delete a client when the nfsd entry is removed.
 289  */
 290 void
 291 nlmsvc_invalidate_client(struct svc_client *clnt)
 292 {
 293         struct nlm_host *host;
 294
 295         if ((host = nlm_lookup_host(clnt, NULL, 0, 0)) != NULL) {
 296                 dprintk("lockd: invalidating client for %s\n", host->h_name);
 297                 nlmsvc_free_host_resources(host);
 298                 host->h_expires = 0;
 299                 nlm_release_host(host);
 300         }
 301 }