11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/fs/lockd/clntlock.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Lock handling for the client side NLM implementation 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds #include <linux/module.h> 101da177e4SLinus Torvalds #include <linux/types.h> 115a0e3ad6STejun Heo #include <linux/slab.h> 121da177e4SLinus Torvalds #include <linux/time.h> 131da177e4SLinus Torvalds #include <linux/nfs_fs.h> 145976687aSJeff Layton #include <linux/sunrpc/addr.h> 151da177e4SLinus Torvalds #include <linux/sunrpc/svc.h> 161da177e4SLinus Torvalds #include <linux/lockd/lockd.h> 17df94f000SJeff Layton #include <linux/kthread.h> 181da177e4SLinus Torvalds 191da177e4SLinus Torvalds #define NLMDBG_FACILITY NLMDBG_CLIENT 201da177e4SLinus Torvalds 211da177e4SLinus Torvalds /* 221da177e4SLinus Torvalds * Local function prototypes 231da177e4SLinus Torvalds */ 241da177e4SLinus Torvalds static int reclaimer(void *ptr); 251da177e4SLinus Torvalds 261da177e4SLinus Torvalds /* 271da177e4SLinus Torvalds * The following functions handle blocking and granting from the 281da177e4SLinus Torvalds * client perspective. 291da177e4SLinus Torvalds */ 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* 321da177e4SLinus Torvalds * This is the representation of a blocked client lock. 331da177e4SLinus Torvalds */ 341da177e4SLinus Torvalds struct nlm_wait { 354f15e2b1STrond Myklebust struct list_head b_list; /* linked list */ 361da177e4SLinus Torvalds wait_queue_head_t b_wait; /* where to wait on */ 371da177e4SLinus Torvalds struct nlm_host * b_host; 381da177e4SLinus Torvalds struct file_lock * b_lock; /* local file lock */ 391da177e4SLinus Torvalds unsigned short b_reclaim; /* got to reclaim lock */ 40e8c5c045SAl Viro __be32 b_status; /* grant callback status */ 411da177e4SLinus Torvalds }; 421da177e4SLinus Torvalds 434f15e2b1STrond Myklebust static LIST_HEAD(nlm_blocked); 4463185942SBryan Schumaker static DEFINE_SPINLOCK(nlm_blocked_lock); 451da177e4SLinus Torvalds 4652c4044dSChuck Lever /** 4752c4044dSChuck Lever * nlmclnt_init - Set up per-NFS mount point lockd data structures 48883bb163SChuck Lever * @nlm_init: pointer to arguments structure 4952c4044dSChuck Lever * 5052c4044dSChuck Lever * Returns pointer to an appropriate nlm_host struct, 5152c4044dSChuck Lever * or an ERR_PTR value. 5252c4044dSChuck Lever */ 53883bb163SChuck Lever struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init) 5452c4044dSChuck Lever { 5552c4044dSChuck Lever struct nlm_host *host; 56883bb163SChuck Lever u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4; 5752c4044dSChuck Lever int status; 5852c4044dSChuck Lever 59e3f70eadSStanislav Kinsbursky status = lockd_up(nlm_init->net); 6052c4044dSChuck Lever if (status < 0) 6152c4044dSChuck Lever return ERR_PTR(status); 6252c4044dSChuck Lever 63d7d20440SChuck Lever host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen, 64883bb163SChuck Lever nlm_init->protocol, nlm_version, 6566697bfdSStanislav Kinsbursky nlm_init->hostname, nlm_init->noresvport, 6666697bfdSStanislav Kinsbursky nlm_init->net); 6752c4044dSChuck Lever if (host == NULL) { 68e3f70eadSStanislav Kinsbursky lockd_down(nlm_init->net); 6952c4044dSChuck Lever return ERR_PTR(-ENOLCK); 7052c4044dSChuck Lever } 7152c4044dSChuck Lever 7252c4044dSChuck Lever return host; 7352c4044dSChuck Lever } 7452c4044dSChuck Lever EXPORT_SYMBOL_GPL(nlmclnt_init); 7552c4044dSChuck Lever 7652c4044dSChuck Lever /** 7752c4044dSChuck Lever * nlmclnt_done - Release resources allocated by nlmclnt_init() 7852c4044dSChuck Lever * @host: nlm_host structure reserved by nlmclnt_init() 7952c4044dSChuck Lever * 8052c4044dSChuck Lever */ 8152c4044dSChuck Lever void nlmclnt_done(struct nlm_host *host) 8252c4044dSChuck Lever { 83e3f70eadSStanislav Kinsbursky struct net *net = host->net; 84e3f70eadSStanislav Kinsbursky 858ea6ecc8SChuck Lever nlmclnt_release_host(host); 86e3f70eadSStanislav Kinsbursky lockd_down(net); 8752c4044dSChuck Lever } 8852c4044dSChuck Lever EXPORT_SYMBOL_GPL(nlmclnt_done); 8952c4044dSChuck Lever 901da177e4SLinus Torvalds /* 91ecdbf769STrond Myklebust * Queue up a lock for blocking so that the GRANTED request can see it 92ecdbf769STrond Myklebust */ 933a649b88STrond Myklebust struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl) 94ecdbf769STrond Myklebust { 95ecdbf769STrond Myklebust struct nlm_wait *block; 96ecdbf769STrond Myklebust 97ecdbf769STrond Myklebust block = kmalloc(sizeof(*block), GFP_KERNEL); 983a649b88STrond Myklebust if (block != NULL) { 99ecdbf769STrond Myklebust block->b_host = host; 100ecdbf769STrond Myklebust block->b_lock = fl; 101ecdbf769STrond Myklebust init_waitqueue_head(&block->b_wait); 102e8c5c045SAl Viro block->b_status = nlm_lck_blocked; 10363185942SBryan Schumaker 10463185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 105ecdbf769STrond Myklebust list_add(&block->b_list, &nlm_blocked); 10663185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 1073a649b88STrond Myklebust } 1083a649b88STrond Myklebust return block; 109ecdbf769STrond Myklebust } 110ecdbf769STrond Myklebust 1113a649b88STrond Myklebust void nlmclnt_finish_block(struct nlm_wait *block) 112ecdbf769STrond Myklebust { 113ecdbf769STrond Myklebust if (block == NULL) 114ecdbf769STrond Myklebust return; 11563185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 116ecdbf769STrond Myklebust list_del(&block->b_list); 11763185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 118ecdbf769STrond Myklebust kfree(block); 119ecdbf769STrond Myklebust } 120ecdbf769STrond Myklebust 121ecdbf769STrond Myklebust /* 1221da177e4SLinus Torvalds * Block on a lock 1231da177e4SLinus Torvalds */ 1243a649b88STrond Myklebust int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout) 1251da177e4SLinus Torvalds { 126ecdbf769STrond Myklebust long ret; 1271da177e4SLinus Torvalds 128ecdbf769STrond Myklebust /* A borken server might ask us to block even if we didn't 129ecdbf769STrond Myklebust * request it. Just say no! 130ecdbf769STrond Myklebust */ 1313a649b88STrond Myklebust if (block == NULL) 132ecdbf769STrond Myklebust return -EAGAIN; 1331da177e4SLinus Torvalds 1341da177e4SLinus Torvalds /* Go to sleep waiting for GRANT callback. Some servers seem 1351da177e4SLinus Torvalds * to lose callbacks, however, so we're going to poll from 1361da177e4SLinus Torvalds * time to time just to make sure. 1371da177e4SLinus Torvalds * 1381da177e4SLinus Torvalds * For now, the retry frequency is pretty high; normally 1391da177e4SLinus Torvalds * a 1 minute timeout would do. See the comment before 1401da177e4SLinus Torvalds * nlmclnt_lock for an explanation. 1411da177e4SLinus Torvalds */ 142ecdbf769STrond Myklebust ret = wait_event_interruptible_timeout(block->b_wait, 143e8c5c045SAl Viro block->b_status != nlm_lck_blocked, 144ecdbf769STrond Myklebust timeout); 1453a649b88STrond Myklebust if (ret < 0) 1463a649b88STrond Myklebust return -ERESTARTSYS; 1471dfd89afSTrond Myklebust /* Reset the lock status after a server reboot so we resend */ 1481dfd89afSTrond Myklebust if (block->b_status == nlm_lck_denied_grace_period) 1491dfd89afSTrond Myklebust block->b_status = nlm_lck_blocked; 150ecdbf769STrond Myklebust req->a_res.status = block->b_status; 1513a649b88STrond Myklebust return 0; 1521da177e4SLinus Torvalds } 1531da177e4SLinus Torvalds 1541da177e4SLinus Torvalds /* 1551da177e4SLinus Torvalds * The server lockd has called us back to tell us the lock was granted 1561da177e4SLinus Torvalds */ 157dcff09f1SChuck Lever __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) 1581da177e4SLinus Torvalds { 1595ac5f9d1STrond Myklebust const struct file_lock *fl = &lock->fl; 1605ac5f9d1STrond Myklebust const struct nfs_fh *fh = &lock->fh; 1611da177e4SLinus Torvalds struct nlm_wait *block; 16252921e02SAl Viro __be32 res = nlm_lck_denied; 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds /* 1651da177e4SLinus Torvalds * Look up blocked request based on arguments. 1661da177e4SLinus Torvalds * Warning: must not use cookie to match it! 1671da177e4SLinus Torvalds */ 16863185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 1694f15e2b1STrond Myklebust list_for_each_entry(block, &nlm_blocked, b_list) { 1705ac5f9d1STrond Myklebust struct file_lock *fl_blocked = block->b_lock; 1715ac5f9d1STrond Myklebust 1727bab377fSTrond Myklebust if (fl_blocked->fl_start != fl->fl_start) 1737bab377fSTrond Myklebust continue; 1747bab377fSTrond Myklebust if (fl_blocked->fl_end != fl->fl_end) 1757bab377fSTrond Myklebust continue; 1767bab377fSTrond Myklebust /* 1777bab377fSTrond Myklebust * Careful! The NLM server will return the 32-bit "pid" that 1787bab377fSTrond Myklebust * we put on the wire: in this case the lockowner "pid". 1797bab377fSTrond Myklebust */ 1807bab377fSTrond Myklebust if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid) 1815ac5f9d1STrond Myklebust continue; 1824516fc04SJeff Layton if (!rpc_cmp_addr(nlm_addr(block->b_host), addr)) 1835ac5f9d1STrond Myklebust continue; 184496ad9aaSAl Viro if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0) 1855ac5f9d1STrond Myklebust continue; 186ecdbf769STrond Myklebust /* Alright, we found a lock. Set the return status 187ecdbf769STrond Myklebust * and wake up the caller 1881da177e4SLinus Torvalds */ 189e8c5c045SAl Viro block->b_status = nlm_granted; 1901da177e4SLinus Torvalds wake_up(&block->b_wait); 191ecdbf769STrond Myklebust res = nlm_granted; 192ecdbf769STrond Myklebust } 19363185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 194ecdbf769STrond Myklebust return res; 1951da177e4SLinus Torvalds } 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds /* 1981da177e4SLinus Torvalds * The following procedures deal with the recovery of locks after a 1991da177e4SLinus Torvalds * server crash. 2001da177e4SLinus Torvalds */ 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds /* 2031da177e4SLinus Torvalds * Reclaim all locks on server host. We do this by spawning a separate 2041da177e4SLinus Torvalds * reclaimer thread. 2051da177e4SLinus Torvalds */ 2061da177e4SLinus Torvalds void 2075c8dd29cSOlaf Kirch nlmclnt_recovery(struct nlm_host *host) 2081da177e4SLinus Torvalds { 209df94f000SJeff Layton struct task_struct *task; 210df94f000SJeff Layton 21128df955aSTrond Myklebust if (!host->h_reclaiming++) { 2121da177e4SLinus Torvalds nlm_get_host(host); 213df94f000SJeff Layton task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name); 214df94f000SJeff Layton if (IS_ERR(task)) 215df94f000SJeff Layton printk(KERN_ERR "lockd: unable to spawn reclaimer " 216df94f000SJeff Layton "thread. Locks for %s won't be reclaimed! " 217df94f000SJeff Layton "(%ld)\n", host->h_name, PTR_ERR(task)); 2181da177e4SLinus Torvalds } 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds static int 2221da177e4SLinus Torvalds reclaimer(void *ptr) 2231da177e4SLinus Torvalds { 2241da177e4SLinus Torvalds struct nlm_host *host = (struct nlm_host *) ptr; 2251da177e4SLinus Torvalds struct nlm_wait *block; 226f25cc71eSTim Gardner struct nlm_rqst *req; 22726bcbf96SChristoph Hellwig struct file_lock *fl, *next; 22828df955aSTrond Myklebust u32 nsmstate; 229e3f70eadSStanislav Kinsbursky struct net *net = host->net; 2301da177e4SLinus Torvalds 231f25cc71eSTim Gardner req = kmalloc(sizeof(*req), GFP_KERNEL); 232f25cc71eSTim Gardner if (!req) { 233f25cc71eSTim Gardner printk(KERN_ERR "lockd: reclaimer unable to alloc memory." 234f25cc71eSTim Gardner " Locks for %s won't be reclaimed!\n", 235f25cc71eSTim Gardner host->h_name); 236f25cc71eSTim Gardner return 0; 237f25cc71eSTim Gardner } 238f25cc71eSTim Gardner 2391da177e4SLinus Torvalds allow_signal(SIGKILL); 2401da177e4SLinus Torvalds 2415c8dd29cSOlaf Kirch down_write(&host->h_rwsem); 242e3f70eadSStanislav Kinsbursky lockd_up(net); /* note: this cannot fail as lockd is already running */ 2431da177e4SLinus Torvalds 244d019bcf0SAdrian Bunk dprintk("lockd: reclaiming locks for host %s\n", host->h_name); 2455c8dd29cSOlaf Kirch 2461da177e4SLinus Torvalds restart: 24728df955aSTrond Myklebust nsmstate = host->h_nsmstate; 2485c8dd29cSOlaf Kirch 2495c8dd29cSOlaf Kirch /* Force a portmap getport - the peer's lockd will 2505c8dd29cSOlaf Kirch * most likely end up on a different port. 2515c8dd29cSOlaf Kirch */ 2520ade060eSOlaf Kirch host->h_nextrebind = jiffies; 2535c8dd29cSOlaf Kirch nlm_rebind_host(host); 2545c8dd29cSOlaf Kirch 2555c8dd29cSOlaf Kirch /* First, reclaim all locks that have been granted. */ 2565c8dd29cSOlaf Kirch list_splice_init(&host->h_granted, &host->h_reclaim); 25726bcbf96SChristoph Hellwig list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) { 2584c060b53STrond Myklebust list_del_init(&fl->fl_u.nfs_fl.list); 2591da177e4SLinus Torvalds 260df94f000SJeff Layton /* 261df94f000SJeff Layton * sending this thread a SIGKILL will result in any unreclaimed 262df94f000SJeff Layton * locks being removed from the h_granted list. This means that 263df94f000SJeff Layton * the kernel will not attempt to reclaim them again if a new 264df94f000SJeff Layton * reclaimer thread is spawned for this host. 265df94f000SJeff Layton */ 2661da177e4SLinus Torvalds if (signalled()) 2674c060b53STrond Myklebust continue; 268f25cc71eSTim Gardner if (nlmclnt_reclaim(host, fl, req) != 0) 26928df955aSTrond Myklebust continue; 2704c060b53STrond Myklebust list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted); 27128df955aSTrond Myklebust if (host->h_nsmstate != nsmstate) { 27228df955aSTrond Myklebust /* Argh! The server rebooted again! */ 2731da177e4SLinus Torvalds goto restart; 2741da177e4SLinus Torvalds } 27528df955aSTrond Myklebust } 2765c8dd29cSOlaf Kirch 2775c8dd29cSOlaf Kirch host->h_reclaiming = 0; 2785c8dd29cSOlaf Kirch up_write(&host->h_rwsem); 279d019bcf0SAdrian Bunk dprintk("NLM: done reclaiming locks for host %s\n", host->h_name); 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds /* Now, wake up all processes that sleep on a blocked lock */ 28263185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 2834f15e2b1STrond Myklebust list_for_each_entry(block, &nlm_blocked, b_list) { 2841da177e4SLinus Torvalds if (block->b_host == host) { 285e8c5c045SAl Viro block->b_status = nlm_lck_denied_grace_period; 2861da177e4SLinus Torvalds wake_up(&block->b_wait); 2871da177e4SLinus Torvalds } 2881da177e4SLinus Torvalds } 28963185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 2901da177e4SLinus Torvalds 2911da177e4SLinus Torvalds /* Release host handle after use */ 2928ea6ecc8SChuck Lever nlmclnt_release_host(host); 293e3f70eadSStanislav Kinsbursky lockd_down(net); 294f25cc71eSTim Gardner kfree(req); 295df94f000SJeff Layton return 0; 2961da177e4SLinus Torvalds } 297