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->f_dentry->d_inode;
  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 = igrab(inode);
  27
  28         /* mds requires start and length rather than start and end */
  29         if (LLONG_MAX == fl->fl_end)
  30                 length = 0;
  31         else
  32                 length = fl->fl_end - fl->fl_start + 1;
  33
  34         dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
  35              "length: %llu, wait: %d, type`: %d", (int)lock_type,
  36              (int)operation, (u64)fl->fl_pid, fl->fl_start,
  37              length, wait, fl->fl_type);
  38
  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 the kernel detects
 113                                  * local deadlock. */
 114                                 ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
 115                                                   CEPH_LOCK_UNLOCK, 0, fl);
 116                                 dout("got %d on posix_lock_file, undid lock", err);
 117                         }
 118                 }
 119
 120         } else {
 121                 dout("mds returned error code %d", err);
 122         }
 123         return err;
 124 }
 125
 126 int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
 127 {
 128         u8 lock_cmd;
 129         int err;
 130         u8 wait = 1;
 131
 132         fl->fl_nspid = get_pid(task_tgid(current));
 133         dout("ceph_flock, fl_pid:%d", fl->fl_pid);
 134
 135         /* set wait bit, then clear it out of cmd*/
 136         if (cmd & LOCK_NB)
 137                 wait = 0;
 138         cmd = cmd & (LOCK_SH | LOCK_EX | LOCK_UN);
 139         /* set command sequence that Ceph wants to see:
 140            shared lock, exclusive lock, or unlock */
 141         if (LOCK_SH == cmd)
 142                 lock_cmd = CEPH_LOCK_SHARED;
 143         else if (LOCK_EX == cmd)
 144                 lock_cmd = CEPH_LOCK_EXCL;
 145         else
 146                 lock_cmd = CEPH_LOCK_UNLOCK;
 147
 148         err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
 149                                 file, lock_cmd, wait, fl);
 150         if (!err) {
 151                 err = flock_lock_file_wait(file, fl);
 152                 if (err) {
 153                         ceph_lock_message(CEPH_LOCK_FLOCK,
 154                                           CEPH_MDS_OP_SETFILELOCK,
 155                                           file, CEPH_LOCK_UNLOCK, 0, fl);
 156                         dout("got %d on flock_lock_file_wait, undid lock", err);
 157                 }
 158         } else {
 159                 dout("mds error code %d", err);
 160         }
 161         return err;
 162 }
 163
 164 /**
 165  * Must be called with BKL already held. Fills in the passed
 166  * counter variables, so you can prepare pagelist metadata before calling
 167  * ceph_encode_locks.
 168  */
 169 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
 170 {
 171         struct file_lock *lock;
 172
 173         *fcntl_count = 0;
 174         *flock_count = 0;
 175
 176         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 177                 if (lock->fl_flags & FL_POSIX)
 178                         ++(*fcntl_count);
 179                 else if (lock->fl_flags & FL_FLOCK)
 180                         ++(*flock_count);
 181         }
 182         dout("counted %d flock locks and %d fcntl locks",
 183              *flock_count, *fcntl_count);
 184 }
 185
 186 /**
 187  * Encode the flock and fcntl locks for the given inode into the pagelist.
 188  * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
 189  * sequential flock locks.
 190  * Must be called with lock_flocks() already held.
 191  * If we encounter more of a specific lock type than expected,
 192  * we return the value 1.
 193  */
 194 int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist,
 195                       int num_fcntl_locks, int num_flock_locks)
 196 {
 197         struct file_lock *lock;
 198         struct ceph_filelock cephlock;
 199         int err = 0;
 200         int seen_fcntl = 0;
 201         int seen_flock = 0;
 202
 203         dout("encoding %d flock and %d fcntl locks", num_flock_locks,
 204              num_fcntl_locks);
 205         err = ceph_pagelist_append(pagelist, &num_fcntl_locks, sizeof(u32));
 206         if (err)
 207                 goto fail;
 208         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 209                 if (lock->fl_flags & FL_POSIX) {
 210                         ++seen_fcntl;
 211                         if (seen_fcntl > num_fcntl_locks) {
 212                                 err = -ENOSPC;
 213                                 goto fail;
 214                         }
 215                         err = lock_to_ceph_filelock(lock, &cephlock);
 216                         if (err)
 217                                 goto fail;
 218                         err = ceph_pagelist_append(pagelist, &cephlock,
 219                                            sizeof(struct ceph_filelock));
 220                 }
 221                 if (err)
 222                         goto fail;
 223         }
 224
 225         err = ceph_pagelist_append(pagelist, &num_flock_locks, sizeof(u32));
 226         if (err)
 227                 goto fail;
 228         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 229                 if (lock->fl_flags & FL_FLOCK) {
 230                         ++seen_flock;
 231                         if (seen_flock > num_flock_locks) {
 232                                 err = -ENOSPC;
 233                                 goto fail;
 234                         }
 235                         err = lock_to_ceph_filelock(lock, &cephlock);
 236                         if (err)
 237                                 goto fail;
 238                         err = ceph_pagelist_append(pagelist, &cephlock,
 239                                            sizeof(struct ceph_filelock));
 240                 }
 241                 if (err)
 242                         goto fail;
 243         }
 244 fail:
 245         return err;
 246 }
 247
 248 /*
 249  * Given a pointer to a lock, convert it to a ceph filelock
 250  */
 251 int lock_to_ceph_filelock(struct file_lock *lock,
 252                           struct ceph_filelock *cephlock)
 253 {
 254         int err = 0;
 255
 256         cephlock->start = cpu_to_le64(lock->fl_start);
 257         cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
 258         cephlock->client = cpu_to_le64(0);
 259         cephlock->pid = cpu_to_le64(lock->fl_pid);
 260         cephlock->pid_namespace =
 261                 cpu_to_le64((u64)(unsigned long)lock->fl_nspid);
 262
 263         switch (lock->fl_type) {
 264         case F_RDLCK:
 265                 cephlock->type = CEPH_LOCK_SHARED;
 266                 break;
 267         case F_WRLCK:
 268                 cephlock->type = CEPH_LOCK_EXCL;
 269                 break;
 270         case F_UNLCK:
 271                 cephlock->type = CEPH_LOCK_UNLOCK;
 272                 break;
 273         default:
 274                 dout("Have unknown lock type %d", lock->fl_type);
 275                 err = -EINVAL;
 276         }
 277
 278         return err;
 279 }