Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/lockd/svclock.c |
| 3 | * |
| 4 | * Handling of server-side locks, mostly of the blocked variety. |
| 5 | * This is the ugliest part of lockd because we tread on very thin ice. |
| 6 | * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc. |
| 7 | * IMNSHO introducing the grant callback into the NLM protocol was one |
| 8 | * of the worst ideas Sun ever had. Except maybe for the idea of doing |
| 9 | * NFS file locking at all. |
| 10 | * |
| 11 | * I'm trying hard to avoid race conditions by protecting most accesses |
| 12 | * to a file's list of blocked locks through a semaphore. The global |
| 13 | * list of blocked locks is not protected in this fashion however. |
| 14 | * Therefore, some functions (such as the RPC callback for the async grant |
| 15 | * call) move blocked locks towards the head of the list *while some other |
| 16 | * process might be traversing it*. This should not be a problem in |
| 17 | * practice, because this will only cause functions traversing the list |
| 18 | * to visit some blocks twice. |
| 19 | * |
| 20 | * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> |
| 21 | */ |
| 22 | |
| 23 | #include <linux/config.h> |
| 24 | #include <linux/types.h> |
| 25 | #include <linux/errno.h> |
| 26 | #include <linux/kernel.h> |
| 27 | #include <linux/sched.h> |
| 28 | #include <linux/smp_lock.h> |
| 29 | #include <linux/sunrpc/clnt.h> |
| 30 | #include <linux/sunrpc/svc.h> |
| 31 | #include <linux/lockd/nlm.h> |
| 32 | #include <linux/lockd/lockd.h> |
| 33 | |
| 34 | #define NLMDBG_FACILITY NLMDBG_SVCLOCK |
| 35 | |
| 36 | #ifdef CONFIG_LOCKD_V4 |
| 37 | #define nlm_deadlock nlm4_deadlock |
| 38 | #else |
| 39 | #define nlm_deadlock nlm_lck_denied |
| 40 | #endif |
| 41 | |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 42 | static void nlmsvc_release_block(struct nlm_block *block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); |
| 44 | static int nlmsvc_remove_block(struct nlm_block *block); |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 45 | |
Trond Myklebust | 5e1abf8 | 2006-03-20 13:44:39 -0500 | [diff] [blame^] | 46 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock); |
| 47 | static void nlmsvc_freegrantargs(struct nlm_rqst *call); |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 48 | static const struct rpc_call_ops nlmsvc_grant_ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | |
| 50 | /* |
| 51 | * The list of blocked locks to retry |
| 52 | */ |
| 53 | static struct nlm_block * nlm_blocked; |
| 54 | |
| 55 | /* |
| 56 | * Insert a blocked lock into the global list |
| 57 | */ |
| 58 | static void |
| 59 | nlmsvc_insert_block(struct nlm_block *block, unsigned long when) |
| 60 | { |
| 61 | struct nlm_block **bp, *b; |
| 62 | |
| 63 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 64 | kref_get(&block->b_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | if (block->b_queued) |
| 66 | nlmsvc_remove_block(block); |
| 67 | bp = &nlm_blocked; |
| 68 | if (when != NLM_NEVER) { |
| 69 | if ((when += jiffies) == NLM_NEVER) |
| 70 | when ++; |
| 71 | while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER) |
| 72 | bp = &b->b_next; |
| 73 | } else |
| 74 | while ((b = *bp) != 0) |
| 75 | bp = &b->b_next; |
| 76 | |
| 77 | block->b_queued = 1; |
| 78 | block->b_when = when; |
| 79 | block->b_next = b; |
| 80 | *bp = block; |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * Remove a block from the global list |
| 85 | */ |
| 86 | static int |
| 87 | nlmsvc_remove_block(struct nlm_block *block) |
| 88 | { |
| 89 | struct nlm_block **bp, *b; |
| 90 | |
| 91 | if (!block->b_queued) |
| 92 | return 1; |
| 93 | for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) { |
| 94 | if (b == block) { |
| 95 | *bp = block->b_next; |
| 96 | block->b_queued = 0; |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 97 | nlmsvc_release_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | return 1; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | return 0; |
| 103 | } |
| 104 | |
| 105 | /* |
| 106 | * Find a block for a given lock and optionally remove it from |
| 107 | * the list. |
| 108 | */ |
| 109 | static struct nlm_block * |
| 110 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove) |
| 111 | { |
| 112 | struct nlm_block **head, *block; |
| 113 | struct file_lock *fl; |
| 114 | |
| 115 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", |
| 116 | file, lock->fl.fl_pid, |
| 117 | (long long)lock->fl.fl_start, |
| 118 | (long long)lock->fl.fl_end, lock->fl.fl_type); |
| 119 | for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) { |
| 120 | fl = &block->b_call.a_args.lock.fl; |
| 121 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", |
| 122 | block->b_file, fl->fl_pid, |
| 123 | (long long)fl->fl_start, |
| 124 | (long long)fl->fl_end, fl->fl_type, |
| 125 | nlmdbg_cookie2a(&block->b_call.a_args.cookie)); |
| 126 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { |
| 127 | if (remove) { |
| 128 | *head = block->b_next; |
| 129 | block->b_queued = 0; |
| 130 | } |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 131 | kref_get(&block->b_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | return block; |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | return NULL; |
| 137 | } |
| 138 | |
| 139 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) |
| 140 | { |
| 141 | if(a->len != b->len) |
| 142 | return 0; |
| 143 | if(memcmp(a->data,b->data,a->len)) |
| 144 | return 0; |
| 145 | return 1; |
| 146 | } |
| 147 | |
| 148 | /* |
| 149 | * Find a block with a given NLM cookie. |
| 150 | */ |
| 151 | static inline struct nlm_block * |
| 152 | nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin) |
| 153 | { |
| 154 | struct nlm_block *block; |
| 155 | |
| 156 | for (block = nlm_blocked; block; block = block->b_next) { |
| 157 | dprintk("cookie: head of blocked queue %p, block %p\n", |
| 158 | nlm_blocked, block); |
| 159 | if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie) |
| 160 | && nlm_cmp_addr(sin, &block->b_host->h_addr)) |
| 161 | break; |
| 162 | } |
| 163 | |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 164 | if (block != NULL) |
| 165 | kref_get(&block->b_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | return block; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Create a block and initialize it. |
| 171 | * |
| 172 | * Note: we explicitly set the cookie of the grant reply to that of |
| 173 | * the blocked lock request. The spec explicitly mentions that the client |
| 174 | * should _not_ rely on the callback containing the same cookie as the |
| 175 | * request, but (as I found out later) that's because some implementations |
| 176 | * do just this. Never mind the standards comittees, they support our |
| 177 | * logging industries. |
| 178 | */ |
| 179 | static inline struct nlm_block * |
| 180 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, |
| 181 | struct nlm_lock *lock, struct nlm_cookie *cookie) |
| 182 | { |
| 183 | struct nlm_block *block; |
| 184 | struct nlm_host *host; |
| 185 | struct nlm_rqst *call; |
| 186 | |
| 187 | /* Create host handle for callback */ |
| 188 | host = nlmclnt_lookup_host(&rqstp->rq_addr, |
| 189 | rqstp->rq_prot, rqstp->rq_vers); |
| 190 | if (host == NULL) |
| 191 | return NULL; |
| 192 | |
| 193 | /* Allocate memory for block, and initialize arguments */ |
| 194 | if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL))) |
| 195 | goto failed; |
| 196 | memset(block, 0, sizeof(*block)); |
| 197 | locks_init_lock(&block->b_call.a_args.lock.fl); |
| 198 | locks_init_lock(&block->b_call.a_res.lock.fl); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 199 | kref_init(&block->b_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | |
Trond Myklebust | 5e1abf8 | 2006-03-20 13:44:39 -0500 | [diff] [blame^] | 201 | if (!nlmsvc_setgrantargs(&block->b_call, lock)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | goto failed_free; |
| 203 | |
| 204 | /* Set notifier function for VFS, and init args */ |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 205 | block->b_call.a_args.lock.fl.fl_flags |= FL_SLEEP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; |
| 207 | block->b_call.a_args.cookie = *cookie; /* see above */ |
| 208 | |
| 209 | dprintk("lockd: created block %p...\n", block); |
| 210 | |
| 211 | /* Create and initialize the block */ |
| 212 | block->b_daemon = rqstp->rq_server; |
| 213 | block->b_host = host; |
| 214 | block->b_file = file; |
| 215 | |
| 216 | /* Add to file's list of blocks */ |
| 217 | block->b_fnext = file->f_blocks; |
| 218 | file->f_blocks = block; |
| 219 | |
| 220 | /* Set up RPC arguments for callback */ |
| 221 | call = &block->b_call; |
| 222 | call->a_host = host; |
| 223 | call->a_flags = RPC_TASK_ASYNC; |
| 224 | |
| 225 | return block; |
| 226 | |
| 227 | failed_free: |
| 228 | kfree(block); |
| 229 | failed: |
| 230 | nlm_release_host(host); |
| 231 | return NULL; |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * Delete a block. If the lock was cancelled or the grant callback |
| 236 | * failed, unlock is set to 1. |
| 237 | * It is the caller's responsibility to check whether the file |
| 238 | * can be closed hereafter. |
| 239 | */ |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 240 | static int nlmsvc_unlink_block(struct nlm_block *block) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | { |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 242 | int status; |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 243 | dprintk("lockd: unlinking block %p...\n", block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | |
| 245 | /* Remove block from list */ |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 246 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call.a_args.lock.fl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | nlmsvc_remove_block(block); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 248 | return status; |
| 249 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 251 | static void nlmsvc_free_block(struct kref *kref) |
| 252 | { |
| 253 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); |
| 254 | struct nlm_file *file = block->b_file; |
| 255 | struct nlm_block **bp; |
| 256 | |
| 257 | dprintk("lockd: freeing block %p...\n", block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | |
| 259 | /* Remove block from file's list of blocks */ |
| 260 | for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) { |
| 261 | if (*bp == block) { |
| 262 | *bp = block->b_fnext; |
| 263 | break; |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | if (block->b_host) |
| 268 | nlm_release_host(block->b_host); |
Trond Myklebust | 5e1abf8 | 2006-03-20 13:44:39 -0500 | [diff] [blame^] | 269 | nlmsvc_freegrantargs(&block->b_call); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | kfree(block); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 271 | } |
| 272 | |
| 273 | static void nlmsvc_release_block(struct nlm_block *block) |
| 274 | { |
| 275 | if (block != NULL) |
| 276 | kref_put(&block->b_count, nlmsvc_free_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | } |
| 278 | |
| 279 | /* |
| 280 | * Loop over all blocks and perform the action specified. |
| 281 | * (NLM_ACT_CHECK handled by nlmsvc_inspect_file). |
| 282 | */ |
| 283 | int |
| 284 | nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) |
| 285 | { |
| 286 | struct nlm_block *block, *next; |
J. Bruce Fields | 64a318e | 2006-01-03 09:55:46 +0100 | [diff] [blame] | 287 | /* XXX: Will everything get cleaned up if we don't unlock here? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | |
| 289 | down(&file->f_sema); |
| 290 | for (block = file->f_blocks; block; block = next) { |
| 291 | next = block->b_fnext; |
| 292 | if (action == NLM_ACT_MARK) |
| 293 | block->b_host->h_inuse = 1; |
| 294 | else if (action == NLM_ACT_UNLOCK) { |
| 295 | if (host == NULL || host == block->b_host) |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 296 | nlmsvc_unlink_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | } |
| 298 | } |
| 299 | up(&file->f_sema); |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | /* |
Trond Myklebust | 5e1abf8 | 2006-03-20 13:44:39 -0500 | [diff] [blame^] | 304 | * Initialize arguments for GRANTED call. The nlm_rqst structure |
| 305 | * has been cleared already. |
| 306 | */ |
| 307 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) |
| 308 | { |
| 309 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); |
| 310 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); |
| 311 | call->a_args.lock.caller = system_utsname.nodename; |
| 312 | call->a_args.lock.oh.len = lock->oh.len; |
| 313 | |
| 314 | /* set default data area */ |
| 315 | call->a_args.lock.oh.data = call->a_owner; |
| 316 | call->a_args.lock.svid = lock->fl.fl_pid; |
| 317 | |
| 318 | if (lock->oh.len > NLMCLNT_OHSIZE) { |
| 319 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); |
| 320 | if (!data) { |
| 321 | nlmsvc_freegrantargs(call); |
| 322 | return 0; |
| 323 | } |
| 324 | call->a_args.lock.oh.data = (u8 *) data; |
| 325 | } |
| 326 | |
| 327 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); |
| 328 | return 1; |
| 329 | } |
| 330 | |
| 331 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) |
| 332 | { |
| 333 | struct file_lock *fl = &call->a_args.lock.fl; |
| 334 | /* |
| 335 | * Check whether we allocated memory for the owner. |
| 336 | */ |
| 337 | if (call->a_args.lock.oh.data != (u8 *) call->a_owner) { |
| 338 | kfree(call->a_args.lock.oh.data); |
| 339 | } |
| 340 | if (fl->fl_ops && fl->fl_ops->fl_release_private) |
| 341 | fl->fl_ops->fl_release_private(fl); |
| 342 | if (fl->fl_lmops && fl->fl_lmops->fl_release_private) |
| 343 | fl->fl_lmops->fl_release_private(fl); |
| 344 | } |
| 345 | |
| 346 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | * Attempt to establish a lock, and if it can't be granted, block it |
| 348 | * if required. |
| 349 | */ |
| 350 | u32 |
| 351 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, |
| 352 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) |
| 353 | { |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 354 | struct nlm_block *block, *newblock = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | int error; |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 356 | u32 ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | |
| 358 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", |
| 359 | file->f_file->f_dentry->d_inode->i_sb->s_id, |
| 360 | file->f_file->f_dentry->d_inode->i_ino, |
| 361 | lock->fl.fl_type, lock->fl.fl_pid, |
| 362 | (long long)lock->fl.fl_start, |
| 363 | (long long)lock->fl.fl_end, |
| 364 | wait); |
| 365 | |
| 366 | |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 367 | lock->fl.fl_flags &= ~FL_SLEEP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | again: |
| 369 | /* Lock file against concurrent access */ |
| 370 | down(&file->f_sema); |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 371 | /* Get existing block (in case client is busy-waiting) */ |
| 372 | block = nlmsvc_lookup_block(file, lock, 0); |
| 373 | if (block == NULL) { |
| 374 | if (newblock != NULL) |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 375 | lock = &newblock->b_call.a_args.lock; |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 376 | } else |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 377 | lock = &block->b_call.a_args.lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 378 | |
Andy Adamson | a85f193 | 2006-03-20 13:44:25 -0500 | [diff] [blame] | 379 | error = posix_lock_file(file->f_file, &lock->fl); |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 380 | lock->fl.fl_flags &= ~FL_SLEEP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | |
Andy Adamson | a85f193 | 2006-03-20 13:44:25 -0500 | [diff] [blame] | 382 | dprintk("lockd: posix_lock_file returned %d\n", error); |
| 383 | |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 384 | switch(error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | case 0: |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 386 | ret = nlm_granted; |
| 387 | goto out; |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 388 | case -EAGAIN: |
| 389 | break; |
| 390 | case -EDEADLK: |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 391 | ret = nlm_deadlock; |
| 392 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | default: /* includes ENOLCK */ |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 394 | ret = nlm_lck_denied_nolocks; |
| 395 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | } |
| 397 | |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 398 | ret = nlm_lck_denied; |
| 399 | if (!wait) |
| 400 | goto out; |
| 401 | |
| 402 | ret = nlm_lck_blocked; |
| 403 | if (block != NULL) |
| 404 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | /* If we don't have a block, create and initialize it. Then |
| 407 | * retry because we may have slept in kmalloc. */ |
| 408 | /* We have to release f_sema as nlmsvc_create_block may try to |
| 409 | * to claim it while doing host garbage collection */ |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 410 | if (newblock == NULL) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | up(&file->f_sema); |
| 412 | dprintk("lockd: blocking on this lock (allocating).\n"); |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 413 | if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | return nlm_lck_denied_nolocks; |
| 415 | goto again; |
| 416 | } |
| 417 | |
| 418 | /* Append to list of blocked */ |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 419 | nlmsvc_insert_block(newblock, NLM_NEVER); |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 420 | out: |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 421 | up(&file->f_sema); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 422 | nlmsvc_release_block(newblock); |
| 423 | nlmsvc_release_block(block); |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 424 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
| 425 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | } |
| 427 | |
| 428 | /* |
| 429 | * Test for presence of a conflicting lock. |
| 430 | */ |
| 431 | u32 |
| 432 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, |
| 433 | struct nlm_lock *conflock) |
| 434 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
| 436 | file->f_file->f_dentry->d_inode->i_sb->s_id, |
| 437 | file->f_file->f_dentry->d_inode->i_ino, |
| 438 | lock->fl.fl_type, |
| 439 | (long long)lock->fl.fl_start, |
| 440 | (long long)lock->fl.fl_end); |
| 441 | |
Andy Adamson | 8dc7c31 | 2006-03-20 13:44:26 -0500 | [diff] [blame] | 442 | if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
Andy Adamson | 8dc7c31 | 2006-03-20 13:44:26 -0500 | [diff] [blame] | 444 | conflock->fl.fl_type, |
| 445 | (long long)conflock->fl.fl_start, |
| 446 | (long long)conflock->fl.fl_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 447 | conflock->caller = "somehost"; /* FIXME */ |
| 448 | conflock->oh.len = 0; /* don't return OH info */ |
Andy Adamson | 8dc7c31 | 2006-03-20 13:44:26 -0500 | [diff] [blame] | 449 | conflock->svid = conflock->fl.fl_pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | return nlm_lck_denied; |
| 451 | } |
| 452 | |
| 453 | return nlm_granted; |
| 454 | } |
| 455 | |
| 456 | /* |
| 457 | * Remove a lock. |
| 458 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies |
| 459 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately |
| 460 | * afterwards. In this case the block will still be there, and hence |
| 461 | * must be removed. |
| 462 | */ |
| 463 | u32 |
| 464 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) |
| 465 | { |
| 466 | int error; |
| 467 | |
| 468 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", |
| 469 | file->f_file->f_dentry->d_inode->i_sb->s_id, |
| 470 | file->f_file->f_dentry->d_inode->i_ino, |
| 471 | lock->fl.fl_pid, |
| 472 | (long long)lock->fl.fl_start, |
| 473 | (long long)lock->fl.fl_end); |
| 474 | |
| 475 | /* First, cancel any lock that might be there */ |
| 476 | nlmsvc_cancel_blocked(file, lock); |
| 477 | |
| 478 | lock->fl.fl_type = F_UNLCK; |
| 479 | error = posix_lock_file(file->f_file, &lock->fl); |
| 480 | |
| 481 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; |
| 482 | } |
| 483 | |
| 484 | /* |
| 485 | * Cancel a previously blocked request. |
| 486 | * |
| 487 | * A cancel request always overrides any grant that may currently |
| 488 | * be in progress. |
| 489 | * The calling procedure must check whether the file can be closed. |
| 490 | */ |
| 491 | u32 |
| 492 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) |
| 493 | { |
| 494 | struct nlm_block *block; |
J. Bruce Fields | 64a318e | 2006-01-03 09:55:46 +0100 | [diff] [blame] | 495 | int status = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | |
| 497 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", |
| 498 | file->f_file->f_dentry->d_inode->i_sb->s_id, |
| 499 | file->f_file->f_dentry->d_inode->i_ino, |
| 500 | lock->fl.fl_pid, |
| 501 | (long long)lock->fl.fl_start, |
| 502 | (long long)lock->fl.fl_end); |
| 503 | |
| 504 | down(&file->f_sema); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 505 | if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) { |
| 506 | status = nlmsvc_unlink_block(block); |
| 507 | nlmsvc_release_block(block); |
| 508 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | up(&file->f_sema); |
J. Bruce Fields | 64a318e | 2006-01-03 09:55:46 +0100 | [diff] [blame] | 510 | return status ? nlm_lck_denied : nlm_granted; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | } |
| 512 | |
| 513 | /* |
| 514 | * Unblock a blocked lock request. This is a callback invoked from the |
| 515 | * VFS layer when a lock on which we blocked is removed. |
| 516 | * |
| 517 | * This function doesn't grant the blocked lock instantly, but rather moves |
| 518 | * the block to the head of nlm_blocked where it can be picked up by lockd. |
| 519 | */ |
| 520 | static void |
| 521 | nlmsvc_notify_blocked(struct file_lock *fl) |
| 522 | { |
| 523 | struct nlm_block **bp, *block; |
| 524 | |
| 525 | dprintk("lockd: VFS unblock notification for block %p\n", fl); |
| 526 | for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) { |
| 527 | if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) { |
| 528 | nlmsvc_insert_block(block, 0); |
| 529 | svc_wake_up(block->b_daemon); |
| 530 | return; |
| 531 | } |
| 532 | } |
| 533 | |
| 534 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); |
| 535 | } |
| 536 | |
| 537 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) |
| 538 | { |
| 539 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; |
| 540 | } |
| 541 | |
| 542 | struct lock_manager_operations nlmsvc_lock_operations = { |
| 543 | .fl_compare_owner = nlmsvc_same_owner, |
| 544 | .fl_notify = nlmsvc_notify_blocked, |
| 545 | }; |
| 546 | |
| 547 | /* |
| 548 | * Try to claim a lock that was previously blocked. |
| 549 | * |
| 550 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async |
| 551 | * RPC thread when notifying the client. This seems like overkill... |
| 552 | * Here's why: |
| 553 | * - we don't want to use a synchronous RPC thread, otherwise |
| 554 | * we might find ourselves hanging on a dead portmapper. |
| 555 | * - Some lockd implementations (e.g. HP) don't react to |
| 556 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. |
| 557 | */ |
| 558 | static void |
| 559 | nlmsvc_grant_blocked(struct nlm_block *block) |
| 560 | { |
| 561 | struct nlm_file *file = block->b_file; |
| 562 | struct nlm_lock *lock = &block->b_call.a_args.lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | int error; |
| 564 | |
| 565 | dprintk("lockd: grant blocked lock %p\n", block); |
| 566 | |
| 567 | /* First thing is lock the file */ |
| 568 | down(&file->f_sema); |
| 569 | |
| 570 | /* Unlink block request from list */ |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 571 | nlmsvc_unlink_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 572 | |
| 573 | /* If b_granted is true this means we've been here before. |
| 574 | * Just retry the grant callback, possibly refreshing the RPC |
| 575 | * binding */ |
| 576 | if (block->b_granted) { |
| 577 | nlm_rebind_host(block->b_host); |
| 578 | goto callback; |
| 579 | } |
| 580 | |
| 581 | /* Try the lock operation again */ |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 582 | lock->fl.fl_flags |= FL_SLEEP; |
Andy Adamson | 5de0e50 | 2006-03-20 13:44:25 -0500 | [diff] [blame] | 583 | error = posix_lock_file(file->f_file, &lock->fl); |
Trond Myklebust | 09c7938 | 2006-03-20 13:44:38 -0500 | [diff] [blame] | 584 | lock->fl.fl_flags &= ~FL_SLEEP; |
| 585 | |
Andy Adamson | 5de0e50 | 2006-03-20 13:44:25 -0500 | [diff] [blame] | 586 | switch (error) { |
| 587 | case 0: |
| 588 | break; |
| 589 | case -EAGAIN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | dprintk("lockd: lock still blocked\n"); |
| 591 | nlmsvc_insert_block(block, NLM_NEVER); |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 592 | goto out_unlock; |
Andy Adamson | 5de0e50 | 2006-03-20 13:44:25 -0500 | [diff] [blame] | 593 | default: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
| 595 | -error, __FUNCTION__); |
| 596 | nlmsvc_insert_block(block, 10 * HZ); |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 597 | goto out_unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | } |
| 599 | |
| 600 | callback: |
| 601 | /* Lock was granted by VFS. */ |
| 602 | dprintk("lockd: GRANTing blocked lock.\n"); |
| 603 | block->b_granted = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | |
| 605 | /* Schedule next grant callback in 30 seconds */ |
| 606 | nlmsvc_insert_block(block, 30 * HZ); |
| 607 | |
| 608 | /* Call the client */ |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 609 | kref_get(&block->b_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG, |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 611 | &nlmsvc_grant_ops) < 0) |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 612 | nlmsvc_release_block(block); |
Andy Adamson | 15dadef | 2006-03-20 13:44:24 -0500 | [diff] [blame] | 613 | out_unlock: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | up(&file->f_sema); |
| 615 | } |
| 616 | |
| 617 | /* |
| 618 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG |
| 619 | * RPC call has succeeded or timed out. |
| 620 | * Like all RPC callbacks, it is invoked by the rpciod process, so it |
| 621 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked |
| 622 | * chain once more in order to have it removed by lockd itself (which can |
| 623 | * then sleep on the file semaphore without disrupting e.g. the nfs client). |
| 624 | */ |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 625 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | { |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 627 | struct nlm_rqst *call = data; |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 628 | struct nlm_block *block = container_of(call, struct nlm_block, b_call); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | unsigned long timeout; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | |
| 631 | dprintk("lockd: GRANT_MSG RPC callback\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | |
| 633 | /* Technically, we should down the file semaphore here. Since we |
| 634 | * move the block towards the head of the queue only, no harm |
| 635 | * can be done, though. */ |
| 636 | if (task->tk_status < 0) { |
| 637 | /* RPC error: Re-insert for retransmission */ |
| 638 | timeout = 10 * HZ; |
| 639 | } else if (block->b_done) { |
| 640 | /* Block already removed, kill it for real */ |
| 641 | timeout = 0; |
| 642 | } else { |
| 643 | /* Call was successful, now wait for client callback */ |
| 644 | timeout = 60 * HZ; |
| 645 | } |
| 646 | nlmsvc_insert_block(block, timeout); |
| 647 | svc_wake_up(block->b_daemon); |
Trond Myklebust | 5e1abf8 | 2006-03-20 13:44:39 -0500 | [diff] [blame^] | 648 | } |
| 649 | |
| 650 | void nlmsvc_grant_release(void *data) |
| 651 | { |
| 652 | nlmsvc_release_block(data); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | } |
| 654 | |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 655 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
| 656 | .rpc_call_done = nlmsvc_grant_callback, |
Trond Myklebust | 5e1abf8 | 2006-03-20 13:44:39 -0500 | [diff] [blame^] | 657 | .rpc_release = nlmsvc_grant_release, |
Trond Myklebust | 963d8fe | 2006-01-03 09:55:04 +0100 | [diff] [blame] | 658 | }; |
| 659 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | /* |
| 661 | * We received a GRANT_RES callback. Try to find the corresponding |
| 662 | * block. |
| 663 | */ |
| 664 | void |
| 665 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) |
| 666 | { |
| 667 | struct nlm_block *block; |
| 668 | struct nlm_file *file; |
| 669 | |
| 670 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", |
| 671 | *(unsigned int *)(cookie->data), |
| 672 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); |
| 673 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) |
| 674 | return; |
| 675 | file = block->b_file; |
| 676 | |
| 677 | file->f_count++; |
| 678 | down(&file->f_sema); |
J. Bruce Fields | f232142 | 2006-01-03 09:55:42 +0100 | [diff] [blame] | 679 | if (block) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
| 681 | /* Try again in a couple of seconds */ |
| 682 | nlmsvc_insert_block(block, 10 * HZ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | } else { |
| 684 | /* Lock is now held by client, or has been rejected. |
| 685 | * In both cases, the block should be removed. */ |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 686 | nlmsvc_unlink_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | } |
| 688 | } |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 689 | up(&file->f_sema); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | nlm_release_file(file); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 691 | nlmsvc_release_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 692 | } |
| 693 | |
| 694 | /* |
| 695 | * Retry all blocked locks that have been notified. This is where lockd |
| 696 | * picks up locks that can be granted, or grant notifications that must |
| 697 | * be retransmitted. |
| 698 | */ |
| 699 | unsigned long |
| 700 | nlmsvc_retry_blocked(void) |
| 701 | { |
| 702 | struct nlm_block *block; |
| 703 | |
| 704 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
| 705 | nlm_blocked, |
| 706 | nlm_blocked? nlm_blocked->b_when : 0); |
| 707 | while ((block = nlm_blocked) != 0) { |
| 708 | if (block->b_when == NLM_NEVER) |
| 709 | break; |
| 710 | if (time_after(block->b_when,jiffies)) |
| 711 | break; |
| 712 | dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n", |
| 713 | block, block->b_when, block->b_done); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 714 | kref_get(&block->b_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | if (block->b_done) |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 716 | nlmsvc_unlink_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | else |
| 718 | nlmsvc_grant_blocked(block); |
Trond Myklebust | 6849c0c | 2006-03-20 13:44:39 -0500 | [diff] [blame] | 719 | nlmsvc_release_block(block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | } |
| 721 | |
| 722 | if ((block = nlm_blocked) && block->b_when != NLM_NEVER) |
| 723 | return (block->b_when - jiffies); |
| 724 | |
| 725 | return MAX_SCHEDULE_TIMEOUT; |
| 726 | } |