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