fs/ceph/locks.c

   1 #include <linux/ceph/ceph_debug.h>
   2
   3 #include <linux/file.h>
   4 #include <linux/namei.h>
   5
   6 #include "super.h"
   7 #include "mds_client.h"
   8 #include <linux/ceph/pagelist.h>
   9
  10 /**
  11  * Implement fcntl and flock locking functions.
  12  */
  13 static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
  14                              int cmd, u8 wait, struct file_lock *fl)
  15 {
  16         struct inode *inode = file_inode(file);
  17         struct ceph_mds_client *mdsc =
  18                 ceph_sb_to_client(inode->i_sb)->mdsc;
  19         struct ceph_mds_request *req;
  20         int err;
  21         u64 length = 0;
  22
  23         req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
  24         if (IS_ERR(req))
  25                 return PTR_ERR(req);
  26         req->r_inode = inode;
  27         ihold(inode);
  28
  29         /* mds requires start and length rather than start and end */
  30         if (LLONG_MAX == fl->fl_end)
  31                 length = 0;
  32         else
  33                 length = fl->fl_end - fl->fl_start + 1;
  34
  35         dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
  36              "length: %llu, wait: %d, type: %d", (int)lock_type,
  37              (int)operation, (u64)fl->fl_pid, fl->fl_start,
  38              length, wait, fl->fl_type);
  39
  40         req->r_args.filelock_change.rule = lock_type;
  41         req->r_args.filelock_change.type = cmd;
  42         req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);
  43         /* This should be adjusted, but I'm not sure if
  44            namespaces actually get id numbers*/
  45         req->r_args.filelock_change.pid_namespace =
  46                 cpu_to_le64((u64)(unsigned long)fl->fl_nspid);
  47         req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
  48         req->r_args.filelock_change.length = cpu_to_le64(length);
  49         req->r_args.filelock_change.wait = wait;
  50
  51         err = ceph_mdsc_do_request(mdsc, inode, req);
  52
  53         if ( operation == CEPH_MDS_OP_GETFILELOCK){
  54                 fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid);
  55                 if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
  56                         fl->fl_type = F_RDLCK;
  57                 else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
  58                         fl->fl_type = F_WRLCK;
  59                 else
  60                         fl->fl_type = F_UNLCK;
  61
  62                 fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
  63                 length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
  64                                                  le64_to_cpu(req->r_reply_info.filelock_reply->length);
  65                 if (length >= 1)
  66                         fl->fl_end = length -1;
  67                 else
  68                         fl->fl_end = 0;
  69
  70         }
  71         ceph_mdsc_put_request(req);
  72         dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
  73              "length: %llu, wait: %d, type: %d, err code %d", (int)lock_type,
  74              (int)operation, (u64)fl->fl_pid, fl->fl_start,
  75              length, wait, fl->fl_type, err);
  76         return err;
  77 }
  78
  79 /**
  80  * Attempt to set an fcntl lock.
  81  * For now, this just goes away to the server. Later it may be more awesome.
  82  */
  83 int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
  84 {
  85         u8 lock_cmd;
  86         int err;
  87         u8 wait = 0;
  88         u16 op = CEPH_MDS_OP_SETFILELOCK;
  89
  90         fl->fl_nspid = get_pid(task_tgid(current));
  91         dout("ceph_lock, fl_pid:%d", fl->fl_pid);
  92
  93         /* set wait bit as appropriate, then make command as Ceph expects it*/
  94         if (F_SETLKW == cmd)
  95                 wait = 1;
  96         if (F_GETLK == cmd)
  97                 op = CEPH_MDS_OP_GETFILELOCK;
  98
  99         if (F_RDLCK == fl->fl_type)
 100                 lock_cmd = CEPH_LOCK_SHARED;
 101         else if (F_WRLCK == fl->fl_type)
 102                 lock_cmd = CEPH_LOCK_EXCL;
 103         else
 104                 lock_cmd = CEPH_LOCK_UNLOCK;
 105
 106         err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
 107         if (!err) {
 108                 if ( op != CEPH_MDS_OP_GETFILELOCK ){
 109                         dout("mds locked, locking locally");
 110                         err = posix_lock_file(file, fl, NULL);
 111                         if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
 112                                 /* undo! This should only happen if
 113                                  * the kernel detects local
 114                                  * deadlock. */
 115                                 ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
 116                                                   CEPH_LOCK_UNLOCK, 0, fl);
 117                                 dout("got %d on posix_lock_file, undid lock",
 118                                      err);
 119                         }
 120                 }
 121
 122         } else if (err == -ERESTARTSYS) {
 123                 dout("undoing lock\n");
 124                 ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
 125                                   CEPH_LOCK_UNLOCK, 0, fl);
 126         }
 127         return err;
 128 }
 129
 130 int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
 131 {
 132         u8 lock_cmd;
 133         int err;
 134         u8 wait = 1;
 135
 136         fl->fl_nspid = get_pid(task_tgid(current));
 137         dout("ceph_flock, fl_pid:%d", fl->fl_pid);
 138
 139         /* set wait bit, then clear it out of cmd*/
 140         if (cmd & LOCK_NB)
 141                 wait = 0;
 142         cmd = cmd & (LOCK_SH | LOCK_EX | LOCK_UN);
 143         /* set command sequence that Ceph wants to see:
 144            shared lock, exclusive lock, or unlock */
 145         if (LOCK_SH == cmd)
 146                 lock_cmd = CEPH_LOCK_SHARED;
 147         else if (LOCK_EX == cmd)
 148                 lock_cmd = CEPH_LOCK_EXCL;
 149         else
 150                 lock_cmd = CEPH_LOCK_UNLOCK;
 151
 152         err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
 153                                 file, lock_cmd, wait, fl);
 154         if (!err) {
 155                 err = flock_lock_file_wait(file, fl);
 156                 if (err) {
 157                         ceph_lock_message(CEPH_LOCK_FLOCK,
 158                                           CEPH_MDS_OP_SETFILELOCK,
 159                                           file, CEPH_LOCK_UNLOCK, 0, fl);
 160                         dout("got %d on flock_lock_file_wait, undid lock", err);
 161                 }
 162         } else if (err == -ERESTARTSYS) {
 163                 dout("undoing lock\n");
 164                 ceph_lock_message(CEPH_LOCK_FLOCK,
 165                                   CEPH_MDS_OP_SETFILELOCK,
 166                                   file, CEPH_LOCK_UNLOCK, 0, fl);
 167         }
 168         return err;
 169 }
 170
 171 /**
 172  * Must be called with BKL already held. Fills in the passed
 173  * counter variables, so you can prepare pagelist metadata before calling
 174  * ceph_encode_locks.
 175  */
 176 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
 177 {
 178         struct file_lock *lock;
 179
 180         *fcntl_count = 0;
 181         *flock_count = 0;
 182
 183         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 184                 if (lock->fl_flags & FL_POSIX)
 185                         ++(*fcntl_count);
 186                 else if (lock->fl_flags & FL_FLOCK)
 187                         ++(*flock_count);
 188         }
 189         dout("counted %d flock locks and %d fcntl locks",
 190              *flock_count, *fcntl_count);
 191 }
 192
 193 /**
 194  * Encode the flock and fcntl locks for the given inode into the pagelist.
 195  * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
 196  * sequential flock locks.
 197  * Must be called with lock_flocks() already held.
 198  * If we encounter more of a specific lock type than expected,
 199  * we return the value 1.
 200  */
 201 int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist,
 202                       int num_fcntl_locks, int num_flock_locks)
 203 {
 204         struct file_lock *lock;
 205         struct ceph_filelock cephlock;
 206         int err = 0;
 207         int seen_fcntl = 0;
 208         int seen_flock = 0;
 209
 210         dout("encoding %d flock and %d fcntl locks", num_flock_locks,
 211              num_fcntl_locks);
 212         err = ceph_pagelist_append(pagelist, &num_fcntl_locks, sizeof(u32));
 213         if (err)
 214                 goto fail;
 215         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 216                 if (lock->fl_flags & FL_POSIX) {
 217                         ++seen_fcntl;
 218                         if (seen_fcntl > num_fcntl_locks) {
 219                                 err = -ENOSPC;
 220                                 goto fail;
 221                         }
 222                         err = lock_to_ceph_filelock(lock, &cephlock);
 223                         if (err)
 224                                 goto fail;
 225                         err = ceph_pagelist_append(pagelist, &cephlock,
 226                                            sizeof(struct ceph_filelock));
 227                 }
 228                 if (err)
 229                         goto fail;
 230         }
 231
 232         err = ceph_pagelist_append(pagelist, &num_flock_locks, sizeof(u32));
 233         if (err)
 234                 goto fail;
 235         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 236                 if (lock->fl_flags & FL_FLOCK) {
 237                         ++seen_flock;
 238                         if (seen_flock > num_flock_locks) {
 239                                 err = -ENOSPC;
 240                                 goto fail;
 241                         }
 242                         err = lock_to_ceph_filelock(lock, &cephlock);
 243                         if (err)
 244                                 goto fail;
 245                         err = ceph_pagelist_append(pagelist, &cephlock,
 246                                            sizeof(struct ceph_filelock));
 247                 }
 248                 if (err)
 249                         goto fail;
 250         }
 251 fail:
 252         return err;
 253 }
 254
 255 /*
 256  * Given a pointer to a lock, convert it to a ceph filelock
 257  */
 258 int lock_to_ceph_filelock(struct file_lock *lock,
 259                           struct ceph_filelock *cephlock)
 260 {
 261         int err = 0;
 262
 263         cephlock->start = cpu_to_le64(lock->fl_start);
 264         cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
 265         cephlock->client = cpu_to_le64(0);
 266         cephlock->pid = cpu_to_le64(lock->fl_pid);
 267         cephlock->pid_namespace =
 268                 cpu_to_le64((u64)(unsigned long)lock->fl_nspid);
 269
 270         switch (lock->fl_type) {
 271         case F_RDLCK:
 272                 cephlock->type = CEPH_LOCK_SHARED;
 273                 break;
 274         case F_WRLCK:
 275                 cephlock->type = CEPH_LOCK_EXCL;
 276                 break;
 277         case F_UNLCK:
 278                 cephlock->type = CEPH_LOCK_UNLOCK;
 279                 break;
 280         default:
 281                 dout("Have unknown lock type %d", lock->fl_type);
 282                 err = -EINVAL;
 283         }
 284
 285         return err;
 286 }