fs/nfs/callback_proc.c

   1 /*
   2  * linux/fs/nfs/callback_proc.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFSv4 callback procedures
   7  */
   8 #include <linux/nfs4.h>
   9 #include <linux/nfs_fs.h>
  10 #include "nfs4_fs.h"
  11 #include "callback.h"
  12 #include "delegation.h"
  13 #include "internal.h"
  14
  15 #ifdef NFS_DEBUG
  16 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  17 #endif
  18
  19 __be32 nfs4_callback_getattr(struct cb_getattrargs *args, struct cb_getattrres *res)
  20 {
  21         struct nfs_client *clp;
  22         struct nfs_delegation *delegation;
  23         struct nfs_inode *nfsi;
  24         struct inode *inode;
  25
  26         res->bitmap[0] = res->bitmap[1] = 0;
  27         res->status = htonl(NFS4ERR_BADHANDLE);
  28         clp = nfs_find_client(args->addr, 4);
  29         if (clp == NULL)
  30                 goto out;
  31
  32         dprintk("NFS: GETATTR callback request from %s\n",
  33                 rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR));
  34
  35         inode = nfs_delegation_find_inode(clp, &args->fh);
  36         if (inode == NULL)
  37                 goto out_putclient;
  38         nfsi = NFS_I(inode);
  39         down_read(&nfsi->rwsem);
  40         delegation = nfsi->delegation;
  41         if (delegation == NULL || (delegation->type & FMODE_WRITE) == 0)
  42                 goto out_iput;
  43         res->size = i_size_read(inode);
  44         res->change_attr = delegation->change_attr;
  45         if (nfsi->npages != 0)
  46                 res->change_attr++;
  47         res->ctime = inode->i_ctime;
  48         res->mtime = inode->i_mtime;
  49         res->bitmap[0] = (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE) &
  50                 args->bitmap[0];
  51         res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY) &
  52                 args->bitmap[1];
  53         res->status = 0;
  54 out_iput:
  55         up_read(&nfsi->rwsem);
  56         iput(inode);
  57 out_putclient:
  58         nfs_put_client(clp);
  59 out:
  60         dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
  61         return res->status;
  62 }
  63
  64 __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy)
  65 {
  66         struct nfs_client *clp;
  67         struct inode *inode;
  68         __be32 res;
  69
  70         res = htonl(NFS4ERR_BADHANDLE);
  71         clp = nfs_find_client(args->addr, 4);
  72         if (clp == NULL)
  73                 goto out;
  74
  75         dprintk("NFS: RECALL callback request from %s\n",
  76                 rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR));
  77
  78         do {
  79                 struct nfs_client *prev = clp;
  80
  81                 inode = nfs_delegation_find_inode(clp, &args->fh);
  82                 if (inode != NULL) {
  83                         /* Set up a helper thread to actually return the delegation */
  84                         switch(nfs_async_inode_return_delegation(inode, &args->stateid)) {
  85                                 case 0:
  86                                         res = 0;
  87                                         break;
  88                                 case -ENOENT:
  89                                         if (res != 0)
  90                                                 res = htonl(NFS4ERR_BAD_STATEID);
  91                                         break;
  92                                 default:
  93                                         res = htonl(NFS4ERR_RESOURCE);
  94                         }
  95                         iput(inode);
  96                 }
  97                 clp = nfs_find_client_next(prev);
  98                 nfs_put_client(prev);
  99         } while (clp != NULL);
 100 out:
 101         dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
 102         return res;
 103 }
 104
 105 #if defined(CONFIG_NFS_V4_1)
 106
 107 /*
 108  * Validate the sequenceID sent by the server.
 109  * Return success if the sequenceID is one more than what we last saw on
 110  * this slot, accounting for wraparound.  Increments the slot's sequence.
 111  *
 112  * We don't yet implement a duplicate request cache, so at this time
 113  * we will log replays, and process them as if we had not seen them before,
 114  * but we don't bump the sequence in the slot.  Not too worried about it,
 115  * since we only currently implement idempotent callbacks anyway.
 116  *
 117  * We have a single slot backchannel at this time, so we don't bother
 118  * checking the used_slots bit array on the table.  The lower layer guarantees
 119  * a single outstanding callback request at a time.
 120  */
 121 static int
 122 validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
 123 {
 124         struct nfs4_slot *slot;
 125
 126         dprintk("%s enter. slotid %d seqid %d\n",
 127                 __func__, slotid, seqid);
 128
 129         if (slotid > NFS41_BC_MAX_CALLBACKS)
 130                 return htonl(NFS4ERR_BADSLOT);
 131
 132         slot = tbl->slots + slotid;
 133         dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);
 134
 135         /* Normal */
 136         if (likely(seqid == slot->seq_nr + 1)) {
 137                 slot->seq_nr++;
 138                 return htonl(NFS4_OK);
 139         }
 140
 141         /* Replay */
 142         if (seqid == slot->seq_nr) {
 143                 dprintk("%s seqid %d is a replay - no DRC available\n",
 144                         __func__, seqid);
 145                 return htonl(NFS4_OK);
 146         }
 147
 148         /* Wraparound */
 149         if (seqid == 1 && (slot->seq_nr + 1) == 0) {
 150                 slot->seq_nr = 1;
 151                 return htonl(NFS4_OK);
 152         }
 153
 154         /* Misordered request */
 155         return htonl(NFS4ERR_SEQ_MISORDERED);
 156 }
 157
 158 /*
 159  * Returns a pointer to a held 'struct nfs_client' that matches the server's
 160  * address, major version number, and session ID.  It is the caller's
 161  * responsibility to release the returned reference.
 162  *
 163  * Returns NULL if there are no connections with sessions, or if no session
 164  * matches the one of interest.
 165  */
 166  static struct nfs_client *find_client_with_session(
 167         const struct sockaddr *addr, u32 nfsversion,
 168         struct nfs4_sessionid *sessionid)
 169 {
 170         struct nfs_client *clp;
 171
 172         clp = nfs_find_client(addr, 4);
 173         if (clp == NULL)
 174                 return NULL;
 175
 176         do {
 177                 struct nfs_client *prev = clp;
 178
 179                 if (clp->cl_session != NULL) {
 180                         if (memcmp(clp->cl_session->sess_id.data,
 181                                         sessionid->data,
 182                                         NFS4_MAX_SESSIONID_LEN) == 0) {
 183                                 /* Returns a held reference to clp */
 184                                 return clp;
 185                         }
 186                 }
 187                 clp = nfs_find_client_next(prev);
 188                 nfs_put_client(prev);
 189         } while (clp != NULL);
 190
 191         return NULL;
 192 }
 193
 194 /* FIXME: referring calls should be processed */
 195 unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
 196                                 struct cb_sequenceres *res)
 197 {
 198         struct nfs_client *clp;
 199         int i, status;
 200
 201         for (i = 0; i < args->csa_nrclists; i++)
 202                 kfree(args->csa_rclists[i].rcl_refcalls);
 203         kfree(args->csa_rclists);
 204
 205         status = htonl(NFS4ERR_BADSESSION);
 206         clp = find_client_with_session(args->csa_addr, 4, &args->csa_sessionid);
 207         if (clp == NULL)
 208                 goto out;
 209
 210         status = validate_seqid(&clp->cl_session->bc_slot_table,
 211                                 args->csa_slotid, args->csa_sequenceid);
 212         if (status)
 213                 goto out_putclient;
 214
 215         memcpy(&res->csr_sessionid, &args->csa_sessionid,
 216                sizeof(res->csr_sessionid));
 217         res->csr_sequenceid = args->csa_sequenceid;
 218         res->csr_slotid = args->csa_slotid;
 219         res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
 220         res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
 221
 222 out_putclient:
 223         nfs_put_client(clp);
 224 out:
 225         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 226         res->csr_status = status;
 227         return res->csr_status;
 228 }
 229
 230 #endif /* CONFIG_NFS_V4_1 */