Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/lockd/clntlock.c |
| 3 | * |
| 4 | * Lock handling for the client side NLM implementation |
| 5 | * |
| 6 | * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> |
| 7 | */ |
| 8 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/types.h> |
| 11 | #include <linux/time.h> |
| 12 | #include <linux/nfs_fs.h> |
| 13 | #include <linux/sunrpc/clnt.h> |
| 14 | #include <linux/sunrpc/svc.h> |
| 15 | #include <linux/lockd/lockd.h> |
| 16 | #include <linux/smp_lock.h> |
| 17 | |
| 18 | #define NLMDBG_FACILITY NLMDBG_CLIENT |
| 19 | |
| 20 | /* |
| 21 | * Local function prototypes |
| 22 | */ |
| 23 | static int reclaimer(void *ptr); |
| 24 | |
| 25 | /* |
| 26 | * The following functions handle blocking and granting from the |
| 27 | * client perspective. |
| 28 | */ |
| 29 | |
| 30 | /* |
| 31 | * This is the representation of a blocked client lock. |
| 32 | */ |
| 33 | struct nlm_wait { |
Trond Myklebust | 4f15e2b | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 34 | struct list_head b_list; /* linked list */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | wait_queue_head_t b_wait; /* where to wait on */ |
| 36 | struct nlm_host * b_host; |
| 37 | struct file_lock * b_lock; /* local file lock */ |
| 38 | unsigned short b_reclaim; /* got to reclaim lock */ |
| 39 | u32 b_status; /* grant callback status */ |
| 40 | }; |
| 41 | |
Trond Myklebust | 4f15e2b | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 42 | static LIST_HEAD(nlm_blocked); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
| 44 | /* |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 45 | * Queue up a lock for blocking so that the GRANTED request can see it |
| 46 | */ |
| 47 | int nlmclnt_prepare_block(struct nlm_rqst *req, struct nlm_host *host, struct file_lock *fl) |
| 48 | { |
| 49 | struct nlm_wait *block; |
| 50 | |
| 51 | BUG_ON(req->a_block != NULL); |
| 52 | block = kmalloc(sizeof(*block), GFP_KERNEL); |
| 53 | if (block == NULL) |
| 54 | return -ENOMEM; |
| 55 | block->b_host = host; |
| 56 | block->b_lock = fl; |
| 57 | init_waitqueue_head(&block->b_wait); |
| 58 | block->b_status = NLM_LCK_BLOCKED; |
| 59 | |
| 60 | list_add(&block->b_list, &nlm_blocked); |
| 61 | req->a_block = block; |
| 62 | |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | void nlmclnt_finish_block(struct nlm_rqst *req) |
| 67 | { |
| 68 | struct nlm_wait *block = req->a_block; |
| 69 | |
| 70 | if (block == NULL) |
| 71 | return; |
| 72 | req->a_block = NULL; |
| 73 | list_del(&block->b_list); |
| 74 | kfree(block); |
| 75 | } |
| 76 | |
| 77 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | * Block on a lock |
| 79 | */ |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 80 | long nlmclnt_block(struct nlm_rqst *req, long timeout) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | { |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 82 | struct nlm_wait *block = req->a_block; |
| 83 | long ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 85 | /* A borken server might ask us to block even if we didn't |
| 86 | * request it. Just say no! |
| 87 | */ |
| 88 | if (!req->a_args.block) |
| 89 | return -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | |
| 91 | /* Go to sleep waiting for GRANT callback. Some servers seem |
| 92 | * to lose callbacks, however, so we're going to poll from |
| 93 | * time to time just to make sure. |
| 94 | * |
| 95 | * For now, the retry frequency is pretty high; normally |
| 96 | * a 1 minute timeout would do. See the comment before |
| 97 | * nlmclnt_lock for an explanation. |
| 98 | */ |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 99 | ret = wait_event_interruptible_timeout(block->b_wait, |
| 100 | block->b_status != NLM_LCK_BLOCKED, |
| 101 | timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 103 | if (block->b_status != NLM_LCK_BLOCKED) { |
| 104 | req->a_res.status = block->b_status; |
| 105 | block->b_status = NLM_LCK_BLOCKED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | } |
| 107 | |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 108 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | } |
| 110 | |
| 111 | /* |
| 112 | * The server lockd has called us back to tell us the lock was granted |
| 113 | */ |
Trond Myklebust | 5ac5f9d | 2006-02-14 13:53:04 -0800 | [diff] [blame^] | 114 | u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | { |
Trond Myklebust | 5ac5f9d | 2006-02-14 13:53:04 -0800 | [diff] [blame^] | 116 | const struct file_lock *fl = &lock->fl; |
| 117 | const struct nfs_fh *fh = &lock->fh; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | struct nlm_wait *block; |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 119 | u32 res = nlm_lck_denied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | |
| 121 | /* |
| 122 | * Look up blocked request based on arguments. |
| 123 | * Warning: must not use cookie to match it! |
| 124 | */ |
Trond Myklebust | 4f15e2b | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 125 | list_for_each_entry(block, &nlm_blocked, b_list) { |
Trond Myklebust | 5ac5f9d | 2006-02-14 13:53:04 -0800 | [diff] [blame^] | 126 | struct file_lock *fl_blocked = block->b_lock; |
| 127 | |
| 128 | if (!nlm_compare_locks(fl_blocked, fl)) |
| 129 | continue; |
| 130 | if (!nlm_cmp_addr(&block->b_host->h_addr, addr)) |
| 131 | continue; |
| 132 | if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_dentry->d_inode) ,fh) != 0) |
| 133 | continue; |
| 134 | /* Alright, we found a lock. Set the return status |
| 135 | * and wake up the caller |
| 136 | */ |
| 137 | block->b_status = NLM_LCK_GRANTED; |
| 138 | wake_up(&block->b_wait); |
| 139 | res = nlm_granted; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | } |
Trond Myklebust | ecdbf76 | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 141 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | } |
| 143 | |
| 144 | /* |
| 145 | * The following procedures deal with the recovery of locks after a |
| 146 | * server crash. |
| 147 | */ |
| 148 | |
| 149 | /* |
| 150 | * Mark the locks for reclaiming. |
| 151 | * FIXME: In 2.5 we don't want to iterate through any global file_lock_list. |
| 152 | * Maintain NLM lock reclaiming lists in the nlm_host instead. |
| 153 | */ |
| 154 | static |
| 155 | void nlmclnt_mark_reclaim(struct nlm_host *host) |
| 156 | { |
| 157 | struct file_lock *fl; |
| 158 | struct inode *inode; |
| 159 | struct list_head *tmp; |
| 160 | |
| 161 | list_for_each(tmp, &file_lock_list) { |
| 162 | fl = list_entry(tmp, struct file_lock, fl_link); |
| 163 | |
| 164 | inode = fl->fl_file->f_dentry->d_inode; |
| 165 | if (inode->i_sb->s_magic != NFS_SUPER_MAGIC) |
| 166 | continue; |
Trond Myklebust | 9b5b1f5 | 2005-12-19 17:11:25 -0500 | [diff] [blame] | 167 | if (fl->fl_u.nfs_fl.owner == NULL) |
| 168 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | if (fl->fl_u.nfs_fl.owner->host != host) |
| 170 | continue; |
| 171 | if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_GRANTED)) |
| 172 | continue; |
| 173 | fl->fl_u.nfs_fl.flags |= NFS_LCK_RECLAIM; |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number, |
| 179 | * that we mark locks for reclaiming, and that we bump the pseudo NSM state. |
| 180 | */ |
| 181 | static inline |
| 182 | void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate) |
| 183 | { |
| 184 | host->h_monitored = 0; |
| 185 | host->h_nsmstate = newstate; |
| 186 | host->h_state++; |
| 187 | host->h_nextrebind = 0; |
| 188 | nlm_rebind_host(host); |
| 189 | nlmclnt_mark_reclaim(host); |
| 190 | dprintk("NLM: reclaiming locks for host %s", host->h_name); |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * Reclaim all locks on server host. We do this by spawning a separate |
| 195 | * reclaimer thread. |
| 196 | */ |
| 197 | void |
| 198 | nlmclnt_recovery(struct nlm_host *host, u32 newstate) |
| 199 | { |
| 200 | if (host->h_reclaiming++) { |
| 201 | if (host->h_nsmstate == newstate) |
| 202 | return; |
| 203 | nlmclnt_prepare_reclaim(host, newstate); |
| 204 | } else { |
| 205 | nlmclnt_prepare_reclaim(host, newstate); |
| 206 | nlm_get_host(host); |
| 207 | __module_get(THIS_MODULE); |
| 208 | if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0) |
| 209 | module_put(THIS_MODULE); |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | static int |
| 214 | reclaimer(void *ptr) |
| 215 | { |
| 216 | struct nlm_host *host = (struct nlm_host *) ptr; |
| 217 | struct nlm_wait *block; |
| 218 | struct list_head *tmp; |
| 219 | struct file_lock *fl; |
| 220 | struct inode *inode; |
| 221 | |
| 222 | daemonize("%s-reclaim", host->h_name); |
| 223 | allow_signal(SIGKILL); |
| 224 | |
| 225 | /* This one ensures that our parent doesn't terminate while the |
| 226 | * reclaim is in progress */ |
| 227 | lock_kernel(); |
| 228 | lockd_up(); |
| 229 | |
| 230 | /* First, reclaim all locks that have been marked. */ |
| 231 | restart: |
| 232 | list_for_each(tmp, &file_lock_list) { |
| 233 | fl = list_entry(tmp, struct file_lock, fl_link); |
| 234 | |
| 235 | inode = fl->fl_file->f_dentry->d_inode; |
| 236 | if (inode->i_sb->s_magic != NFS_SUPER_MAGIC) |
| 237 | continue; |
Trond Myklebust | 9b5b1f5 | 2005-12-19 17:11:25 -0500 | [diff] [blame] | 238 | if (fl->fl_u.nfs_fl.owner == NULL) |
| 239 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | if (fl->fl_u.nfs_fl.owner->host != host) |
| 241 | continue; |
| 242 | if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM)) |
| 243 | continue; |
| 244 | |
| 245 | fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM; |
| 246 | nlmclnt_reclaim(host, fl); |
| 247 | if (signalled()) |
| 248 | break; |
| 249 | goto restart; |
| 250 | } |
| 251 | |
| 252 | host->h_reclaiming = 0; |
| 253 | |
| 254 | /* Now, wake up all processes that sleep on a blocked lock */ |
Trond Myklebust | 4f15e2b | 2005-06-22 17:16:31 +0000 | [diff] [blame] | 255 | list_for_each_entry(block, &nlm_blocked, b_list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | if (block->b_host == host) { |
| 257 | block->b_status = NLM_LCK_DENIED_GRACE_PERIOD; |
| 258 | wake_up(&block->b_wait); |
| 259 | } |
| 260 | } |
| 261 | |
| 262 | /* Release host handle after use */ |
| 263 | nlm_release_host(host); |
| 264 | lockd_down(); |
| 265 | unlock_kernel(); |
| 266 | module_put_and_exit(0); |
| 267 | } |