fs/lockd/svcshare.c

   1 /*
   2  * linux/fs/lockd/svcshare.c
   3  *
   4  * Management of DOS shares.
   5  *
   6  * Copyright (C) 1996 Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/sched.h>
  10 #include <linux/unistd.h>
  11 #include <linux/string.h>
  12 #include <linux/slab.h>
  13
  14 #include <linux/sunrpc/clnt.h>
  15 #include <linux/sunrpc/svc.h>
  16 #include <linux/lockd/lockd.h>
  17 #include <linux/lockd/share.h>
  18
  19 static inline int
  20 nlm_cmp_owner(struct nlm_share *share, struct xdr_netobj *oh)
  21 {
  22         return share->s_owner.len == oh->len
  23             && !memcmp(share->s_owner.data, oh->data, oh->len);
  24 }
  25
  26 u32
  27 nlmsvc_share_file(struct nlm_host *host, struct nlm_file *file,
  28                         struct nlm_args *argp)
  29 {
  30         struct nlm_share        *share;
  31         struct xdr_netobj       *oh = &argp->lock.oh;
  32         u8                      *ohdata;
  33
  34         for (share = file->f_shares; share; share = share->s_next) {
  35                 if (share->s_host == host && nlm_cmp_owner(share, oh))
  36                         goto update;
  37                 if ((argp->fsm_access & share->s_mode)
  38                  || (argp->fsm_mode   & share->s_access ))
  39                         return nlm_lck_denied;
  40         }
  41
  42         share = (struct nlm_share *) kmalloc(sizeof(*share) + oh->len,
  43                                                 GFP_KERNEL);
  44         if (share == NULL)
  45                 return nlm_lck_denied_nolocks;
  46
  47         /* Copy owner handle */
  48         ohdata = (u8 *) (share + 1);
  49         memcpy(ohdata, oh->data, oh->len);
  50
  51         share->s_file       = file;
  52         share->s_host       = host;
  53         share->s_owner.data = ohdata;
  54         share->s_owner.len  = oh->len;
  55         share->s_next       = file->f_shares;
  56         file->f_shares      = share;
  57
  58 update:
  59         share->s_access = argp->fsm_access;
  60         share->s_mode   = argp->fsm_mode;
  61         return nlm_granted;
  62 }
  63
  64 /*
  65  * Delete a share.
  66  */
  67 u32
  68 nlmsvc_unshare_file(struct nlm_host *host, struct nlm_file *file,
  69                         struct nlm_args *argp)
  70 {
  71         struct nlm_share        *share, **shpp;
  72         struct xdr_netobj       *oh = &argp->lock.oh;
  73
  74         for (shpp = &file->f_shares; (share = *shpp); shpp = &share->s_next) {
  75                 if (share->s_host == host && nlm_cmp_owner(share, oh)) {
  76                         *shpp = share->s_next;
  77                         kfree(share);
  78                         return nlm_granted;
  79                 }
  80         }
  81
  82         /* X/Open spec says return success even if there was no
  83          * corresponding share. */
  84         return nlm_granted;
  85 }
  86
  87 /*
  88  * Traverse all shares for a given file (and host).
  89  * NLM_ACT_CHECK is handled by nlmsvc_inspect_file.
  90  */
  91 int
  92 nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file, int action)
  93 {
  94         struct nlm_share        *share, **shpp;
  95
  96         shpp = &file->f_shares;
  97         while ((share = *shpp) !=  NULL) {
  98                 if (action == NLM_ACT_MARK)
  99                         share->s_host->h_inuse = 1;
 100                 else if (action == NLM_ACT_UNLOCK) {
 101                         if (host == NULL || host == share->s_host) {
 102                                 *shpp = share->s_next;
 103                                 kfree(share);
 104                                 continue;
 105                         }
 106                 }
 107                 shpp = &share->s_next;
 108         }
 109
 110         return 0;
 111 }