fs/ceph/locks.c

   1 #include "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 "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, (u64)fl->fl_nspid,
  86                                 lock_cmd, fl->fl_start,
  87                                 length, wait);
  88         if (!err) {
  89                 dout("mds locked, locking locally");
  90                 err = posix_lock_file(file, fl, NULL);
  91                 if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
  92                         /* undo! This should only happen if the kernel detects
  93                          * local deadlock. */
  94                         ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
  95                                           (u64)fl->fl_pid, (u64)fl->fl_nspid,
  96                                           CEPH_LOCK_UNLOCK, fl->fl_start,
  97                                           length, 0);
  98                         dout("got %d on posix_lock_file, undid lock", err);
  99                 }
 100         } else {
 101                 dout("mds returned error code %d", err);
 102         }
 103         return err;
 104 }
 105
 106 int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
 107 {
 108         u64 length;
 109         u8 lock_cmd;
 110         int err;
 111         u8 wait = 1;
 112
 113         fl->fl_nspid = get_pid(task_tgid(current));
 114         dout("ceph_flock, fl_pid:%d", fl->fl_pid);
 115
 116         /* set wait bit, then clear it out of cmd*/
 117         if (cmd & LOCK_NB)
 118                 wait = 0;
 119         cmd = cmd & (LOCK_SH | LOCK_EX | LOCK_UN);
 120         /* set command sequence that Ceph wants to see:
 121            shared lock, exclusive lock, or unlock */
 122         if (LOCK_SH == cmd)
 123                 lock_cmd = CEPH_LOCK_SHARED;
 124         else if (LOCK_EX == cmd)
 125                 lock_cmd = CEPH_LOCK_EXCL;
 126         else
 127                 lock_cmd = CEPH_LOCK_UNLOCK;
 128         /* mds requires start and length rather than start and end */
 129         if (LLONG_MAX == fl->fl_end)
 130                 length = 0;
 131         else
 132                 length = fl->fl_end - fl->fl_start + 1;
 133
 134         err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
 135                                 file, (u64)fl->fl_pid, (u64)fl->fl_nspid,
 136                                 lock_cmd, fl->fl_start,
 137                                 length, wait);
 138         if (!err) {
 139                 err = flock_lock_file_wait(file, fl);
 140                 if (err) {
 141                         ceph_lock_message(CEPH_LOCK_FLOCK,
 142                                           CEPH_MDS_OP_SETFILELOCK,
 143                                           file, (u64)fl->fl_pid,
 144                                           (u64)fl->fl_nspid,
 145                                           CEPH_LOCK_UNLOCK, fl->fl_start,
 146                                           length, 0);
 147                         dout("got %d on flock_lock_file_wait, undid lock", err);
 148                 }
 149         } else {
 150                 dout("mds error code %d", err);
 151         }
 152         return err;
 153 }
 154
 155 /**
 156  * Must be called with BKL already held. Fills in the passed
 157  * counter variables, so you can prepare pagelist metadata before calling
 158  * ceph_encode_locks.
 159  */
 160 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
 161 {
 162         struct file_lock *lock;
 163
 164         *fcntl_count = 0;
 165         *flock_count = 0;
 166
 167         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 168                 if (lock->fl_flags & FL_POSIX)
 169                         ++(*fcntl_count);
 170                 else if (lock->fl_flags & FL_FLOCK)
 171                         ++(*flock_count);
 172         }
 173         dout("counted %d flock locks and %d fcntl locks",
 174              *flock_count, *fcntl_count);
 175 }
 176
 177 /**
 178  * Encode the flock and fcntl locks for the given inode into the pagelist.
 179  * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
 180  * sequential flock locks.
 181  * Must be called with BLK already held, and the lock numbers should have
 182  * been gathered under the same lock holding window.
 183  */
 184 int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist,
 185                       int num_fcntl_locks, int num_flock_locks)
 186 {
 187         struct file_lock *lock;
 188         struct ceph_filelock cephlock;
 189         int err = 0;
 190
 191         dout("encoding %d flock and %d fcntl locks", num_flock_locks,
 192              num_fcntl_locks);
 193         err = ceph_pagelist_append(pagelist, &num_fcntl_locks, sizeof(u32));
 194         if (err)
 195                 goto fail;
 196         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 197                 if (lock->fl_flags & FL_POSIX) {
 198                         err = lock_to_ceph_filelock(lock, &cephlock);
 199                         if (err)
 200                                 goto fail;
 201                         err = ceph_pagelist_append(pagelist, &cephlock,
 202                                            sizeof(struct ceph_filelock));
 203                 }
 204                 if (err)
 205                         goto fail;
 206         }
 207
 208         err = ceph_pagelist_append(pagelist, &num_flock_locks, sizeof(u32));
 209         if (err)
 210                 goto fail;
 211         for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
 212                 if (lock->fl_flags & FL_FLOCK) {
 213                         err = lock_to_ceph_filelock(lock, &cephlock);
 214                         if (err)
 215                                 goto fail;
 216                         err = ceph_pagelist_append(pagelist, &cephlock,
 217                                            sizeof(struct ceph_filelock));
 218                 }
 219                 if (err)
 220                         goto fail;
 221         }
 222 fail:
 223         return err;
 224 }
 225
 226 /*
 227  * Given a pointer to a lock, convert it to a ceph filelock
 228  */
 229 int lock_to_ceph_filelock(struct file_lock *lock,
 230                           struct ceph_filelock *cephlock)
 231 {
 232         int err = 0;
 233
 234         cephlock->start = cpu_to_le64(lock->fl_start);
 235         cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
 236         cephlock->client = cpu_to_le64(0);
 237         cephlock->pid = cpu_to_le64(lock->fl_pid);
 238         cephlock->pid_namespace = cpu_to_le64((u64)lock->fl_nspid);
 239
 240         switch (lock->fl_type) {
 241         case F_RDLCK:
 242                 cephlock->type = CEPH_LOCK_SHARED;
 243                 break;
 244         case F_WRLCK:
 245                 cephlock->type = CEPH_LOCK_EXCL;
 246                 break;
 247         case F_UNLCK:
 248                 cephlock->type = CEPH_LOCK_UNLOCK;
 249                 break;
 250         default:
 251                 dout("Have unknown lock type %d", lock->fl_type);
 252                 err = -EINVAL;
 253         }
 254
 255         return err;
 256 }