1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * linux/fs/lockd/clntlock.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Lock handling for the client side NLM implementation 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds #include <linux/module.h> 111da177e4SLinus Torvalds #include <linux/types.h> 125a0e3ad6STejun Heo #include <linux/slab.h> 131da177e4SLinus Torvalds #include <linux/time.h> 141da177e4SLinus Torvalds #include <linux/nfs_fs.h> 155976687aSJeff Layton #include <linux/sunrpc/addr.h> 161da177e4SLinus Torvalds #include <linux/sunrpc/svc.h> 171da177e4SLinus Torvalds #include <linux/lockd/lockd.h> 18df94f000SJeff Layton #include <linux/kthread.h> 191da177e4SLinus Torvalds 201da177e4SLinus Torvalds #define NLMDBG_FACILITY NLMDBG_CLIENT 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds /* 231da177e4SLinus Torvalds * Local function prototypes 241da177e4SLinus Torvalds */ 251da177e4SLinus Torvalds static int reclaimer(void *ptr); 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds /* 281da177e4SLinus Torvalds * The following functions handle blocking and granting from the 291da177e4SLinus Torvalds * client perspective. 301da177e4SLinus Torvalds */ 311da177e4SLinus Torvalds 324f15e2b1STrond Myklebust static LIST_HEAD(nlm_blocked); 3363185942SBryan Schumaker static DEFINE_SPINLOCK(nlm_blocked_lock); 341da177e4SLinus Torvalds 3552c4044dSChuck Lever /** 3652c4044dSChuck Lever * nlmclnt_init - Set up per-NFS mount point lockd data structures 37883bb163SChuck Lever * @nlm_init: pointer to arguments structure 3852c4044dSChuck Lever * 3952c4044dSChuck Lever * Returns pointer to an appropriate nlm_host struct, 4052c4044dSChuck Lever * or an ERR_PTR value. 4152c4044dSChuck Lever */ 42883bb163SChuck Lever struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init) 4352c4044dSChuck Lever { 4452c4044dSChuck Lever struct nlm_host *host; 45883bb163SChuck Lever u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4; 4652c4044dSChuck Lever int status; 4752c4044dSChuck Lever 4840373b12STrond Myklebust status = lockd_up(nlm_init->net, nlm_init->cred); 4952c4044dSChuck Lever if (status < 0) 5052c4044dSChuck Lever return ERR_PTR(status); 5152c4044dSChuck Lever 52d7d20440SChuck Lever host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen, 53883bb163SChuck Lever nlm_init->protocol, nlm_version, 5466697bfdSStanislav Kinsbursky nlm_init->hostname, nlm_init->noresvport, 55b422df91STrond Myklebust nlm_init->net, nlm_init->cred); 569a1b6bf8STrond Myklebust if (host == NULL) 579a1b6bf8STrond Myklebust goto out_nohost; 589a1b6bf8STrond Myklebust if (host->h_rpcclnt == NULL && nlm_bind_host(host) == NULL) 599a1b6bf8STrond Myklebust goto out_nobind; 6052c4044dSChuck Lever 61b1ece737SBenjamin Coddington host->h_nlmclnt_ops = nlm_init->nlmclnt_ops; 6252c4044dSChuck Lever return host; 639a1b6bf8STrond Myklebust out_nobind: 649a1b6bf8STrond Myklebust nlmclnt_release_host(host); 659a1b6bf8STrond Myklebust out_nohost: 669a1b6bf8STrond Myklebust lockd_down(nlm_init->net); 679a1b6bf8STrond Myklebust return ERR_PTR(-ENOLCK); 6852c4044dSChuck Lever } 6952c4044dSChuck Lever EXPORT_SYMBOL_GPL(nlmclnt_init); 7052c4044dSChuck Lever 7152c4044dSChuck Lever /** 7252c4044dSChuck Lever * nlmclnt_done - Release resources allocated by nlmclnt_init() 7352c4044dSChuck Lever * @host: nlm_host structure reserved by nlmclnt_init() 7452c4044dSChuck Lever * 7552c4044dSChuck Lever */ 7652c4044dSChuck Lever void nlmclnt_done(struct nlm_host *host) 7752c4044dSChuck Lever { 78e3f70eadSStanislav Kinsbursky struct net *net = host->net; 79e3f70eadSStanislav Kinsbursky 808ea6ecc8SChuck Lever nlmclnt_release_host(host); 81e3f70eadSStanislav Kinsbursky lockd_down(net); 8252c4044dSChuck Lever } 8352c4044dSChuck Lever EXPORT_SYMBOL_GPL(nlmclnt_done); 8452c4044dSChuck Lever 85*2005f5b9SJeff Layton void nlmclnt_prepare_block(struct nlm_wait *block, struct nlm_host *host, struct file_lock *fl) 86ecdbf769STrond Myklebust { 87ecdbf769STrond Myklebust block->b_host = host; 88ecdbf769STrond Myklebust block->b_lock = fl; 89ecdbf769STrond Myklebust init_waitqueue_head(&block->b_wait); 90e8c5c045SAl Viro block->b_status = nlm_lck_blocked; 91*2005f5b9SJeff Layton } 9263185942SBryan Schumaker 93*2005f5b9SJeff Layton /* 94*2005f5b9SJeff Layton * Queue up a lock for blocking so that the GRANTED request can see it 95*2005f5b9SJeff Layton */ 96*2005f5b9SJeff Layton void nlmclnt_queue_block(struct nlm_wait *block) 97*2005f5b9SJeff Layton { 9863185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 99ecdbf769STrond Myklebust list_add(&block->b_list, &nlm_blocked); 10063185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 1013a649b88STrond Myklebust } 102ecdbf769STrond Myklebust 103*2005f5b9SJeff Layton /* 104*2005f5b9SJeff Layton * Dequeue the block and return its final status 105*2005f5b9SJeff Layton */ 106*2005f5b9SJeff Layton __be32 nlmclnt_dequeue_block(struct nlm_wait *block) 107ecdbf769STrond Myklebust { 108*2005f5b9SJeff Layton __be32 status; 109*2005f5b9SJeff Layton 11063185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 111ecdbf769STrond Myklebust list_del(&block->b_list); 112*2005f5b9SJeff Layton status = block->b_status; 11363185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 114*2005f5b9SJeff Layton return status; 115ecdbf769STrond Myklebust } 116ecdbf769STrond Myklebust 117ecdbf769STrond Myklebust /* 1181da177e4SLinus Torvalds * Block on a lock 1191da177e4SLinus Torvalds */ 120*2005f5b9SJeff Layton int nlmclnt_wait(struct nlm_wait *block, struct nlm_rqst *req, long timeout) 1211da177e4SLinus Torvalds { 122ecdbf769STrond Myklebust long ret; 1231da177e4SLinus Torvalds 124ecdbf769STrond Myklebust /* A borken server might ask us to block even if we didn't 125ecdbf769STrond Myklebust * request it. Just say no! 126ecdbf769STrond Myklebust */ 1273a649b88STrond Myklebust if (block == NULL) 128ecdbf769STrond Myklebust return -EAGAIN; 1291da177e4SLinus Torvalds 1301da177e4SLinus Torvalds /* Go to sleep waiting for GRANT callback. Some servers seem 1311da177e4SLinus Torvalds * to lose callbacks, however, so we're going to poll from 1321da177e4SLinus Torvalds * time to time just to make sure. 1331da177e4SLinus Torvalds * 1341da177e4SLinus Torvalds * For now, the retry frequency is pretty high; normally 1351da177e4SLinus Torvalds * a 1 minute timeout would do. See the comment before 1361da177e4SLinus Torvalds * nlmclnt_lock for an explanation. 1371da177e4SLinus Torvalds */ 138ecdbf769STrond Myklebust ret = wait_event_interruptible_timeout(block->b_wait, 139e8c5c045SAl Viro block->b_status != nlm_lck_blocked, 140ecdbf769STrond Myklebust timeout); 1413a649b88STrond Myklebust if (ret < 0) 1423a649b88STrond Myklebust return -ERESTARTSYS; 1431dfd89afSTrond Myklebust /* Reset the lock status after a server reboot so we resend */ 1441dfd89afSTrond Myklebust if (block->b_status == nlm_lck_denied_grace_period) 1451dfd89afSTrond Myklebust block->b_status = nlm_lck_blocked; 1463a649b88STrond Myklebust return 0; 1471da177e4SLinus Torvalds } 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds /* 1501da177e4SLinus Torvalds * The server lockd has called us back to tell us the lock was granted 1511da177e4SLinus Torvalds */ 152dcff09f1SChuck Lever __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) 1531da177e4SLinus Torvalds { 1545ac5f9d1STrond Myklebust const struct file_lock *fl = &lock->fl; 1555ac5f9d1STrond Myklebust const struct nfs_fh *fh = &lock->fh; 1561da177e4SLinus Torvalds struct nlm_wait *block; 15752921e02SAl Viro __be32 res = nlm_lck_denied; 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds /* 1601da177e4SLinus Torvalds * Look up blocked request based on arguments. 1611da177e4SLinus Torvalds * Warning: must not use cookie to match it! 1621da177e4SLinus Torvalds */ 16363185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 1644f15e2b1STrond Myklebust list_for_each_entry(block, &nlm_blocked, b_list) { 1655ac5f9d1STrond Myklebust struct file_lock *fl_blocked = block->b_lock; 1665ac5f9d1STrond Myklebust 1677bab377fSTrond Myklebust if (fl_blocked->fl_start != fl->fl_start) 1687bab377fSTrond Myklebust continue; 1697bab377fSTrond Myklebust if (fl_blocked->fl_end != fl->fl_end) 1707bab377fSTrond Myklebust continue; 1717bab377fSTrond Myklebust /* 1727bab377fSTrond Myklebust * Careful! The NLM server will return the 32-bit "pid" that 1737bab377fSTrond Myklebust * we put on the wire: in this case the lockowner "pid". 1747bab377fSTrond Myklebust */ 1757bab377fSTrond Myklebust if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid) 1765ac5f9d1STrond Myklebust continue; 1774516fc04SJeff Layton if (!rpc_cmp_addr(nlm_addr(block->b_host), addr)) 1785ac5f9d1STrond Myklebust continue; 179c65454a9SJeff Layton if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)), fh) != 0) 1805ac5f9d1STrond Myklebust continue; 181ecdbf769STrond Myklebust /* Alright, we found a lock. Set the return status 182ecdbf769STrond Myklebust * and wake up the caller 1831da177e4SLinus Torvalds */ 184e8c5c045SAl Viro block->b_status = nlm_granted; 1851da177e4SLinus Torvalds wake_up(&block->b_wait); 186ecdbf769STrond Myklebust res = nlm_granted; 187ecdbf769STrond Myklebust } 18863185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 189ecdbf769STrond Myklebust return res; 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds /* 1931da177e4SLinus Torvalds * The following procedures deal with the recovery of locks after a 1941da177e4SLinus Torvalds * server crash. 1951da177e4SLinus Torvalds */ 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds /* 1981da177e4SLinus Torvalds * Reclaim all locks on server host. We do this by spawning a separate 1991da177e4SLinus Torvalds * reclaimer thread. 2001da177e4SLinus Torvalds */ 2011da177e4SLinus Torvalds void 2025c8dd29cSOlaf Kirch nlmclnt_recovery(struct nlm_host *host) 2031da177e4SLinus Torvalds { 204df94f000SJeff Layton struct task_struct *task; 205df94f000SJeff Layton 20628df955aSTrond Myklebust if (!host->h_reclaiming++) { 2071da177e4SLinus Torvalds nlm_get_host(host); 208df94f000SJeff Layton task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name); 209df94f000SJeff Layton if (IS_ERR(task)) 210df94f000SJeff Layton printk(KERN_ERR "lockd: unable to spawn reclaimer " 211df94f000SJeff Layton "thread. Locks for %s won't be reclaimed! " 212df94f000SJeff Layton "(%ld)\n", host->h_name, PTR_ERR(task)); 2131da177e4SLinus Torvalds } 2141da177e4SLinus Torvalds } 2151da177e4SLinus Torvalds 2161da177e4SLinus Torvalds static int 2171da177e4SLinus Torvalds reclaimer(void *ptr) 2181da177e4SLinus Torvalds { 2191da177e4SLinus Torvalds struct nlm_host *host = (struct nlm_host *) ptr; 2201da177e4SLinus Torvalds struct nlm_wait *block; 221f25cc71eSTim Gardner struct nlm_rqst *req; 22226bcbf96SChristoph Hellwig struct file_lock *fl, *next; 22328df955aSTrond Myklebust u32 nsmstate; 224e3f70eadSStanislav Kinsbursky struct net *net = host->net; 2251da177e4SLinus Torvalds 226f25cc71eSTim Gardner req = kmalloc(sizeof(*req), GFP_KERNEL); 22758a69893SMarkus Elfring if (!req) 228f25cc71eSTim Gardner return 0; 229f25cc71eSTim Gardner 2301da177e4SLinus Torvalds allow_signal(SIGKILL); 2311da177e4SLinus Torvalds 2325c8dd29cSOlaf Kirch down_write(&host->h_rwsem); 23340373b12STrond Myklebust lockd_up(net, NULL); /* note: this cannot fail as lockd is already running */ 2341da177e4SLinus Torvalds 235d019bcf0SAdrian Bunk dprintk("lockd: reclaiming locks for host %s\n", host->h_name); 2365c8dd29cSOlaf Kirch 2371da177e4SLinus Torvalds restart: 23828df955aSTrond Myklebust nsmstate = host->h_nsmstate; 2395c8dd29cSOlaf Kirch 2405c8dd29cSOlaf Kirch /* Force a portmap getport - the peer's lockd will 2415c8dd29cSOlaf Kirch * most likely end up on a different port. 2425c8dd29cSOlaf Kirch */ 2430ade060eSOlaf Kirch host->h_nextrebind = jiffies; 2445c8dd29cSOlaf Kirch nlm_rebind_host(host); 2455c8dd29cSOlaf Kirch 2465c8dd29cSOlaf Kirch /* First, reclaim all locks that have been granted. */ 2475c8dd29cSOlaf Kirch list_splice_init(&host->h_granted, &host->h_reclaim); 24826bcbf96SChristoph Hellwig list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) { 2494c060b53STrond Myklebust list_del_init(&fl->fl_u.nfs_fl.list); 2501da177e4SLinus Torvalds 251df94f000SJeff Layton /* 252df94f000SJeff Layton * sending this thread a SIGKILL will result in any unreclaimed 253df94f000SJeff Layton * locks being removed from the h_granted list. This means that 254df94f000SJeff Layton * the kernel will not attempt to reclaim them again if a new 255df94f000SJeff Layton * reclaimer thread is spawned for this host. 256df94f000SJeff Layton */ 2571da177e4SLinus Torvalds if (signalled()) 2584c060b53STrond Myklebust continue; 259f25cc71eSTim Gardner if (nlmclnt_reclaim(host, fl, req) != 0) 26028df955aSTrond Myklebust continue; 2614c060b53STrond Myklebust list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted); 26228df955aSTrond Myklebust if (host->h_nsmstate != nsmstate) { 26328df955aSTrond Myklebust /* Argh! The server rebooted again! */ 2641da177e4SLinus Torvalds goto restart; 2651da177e4SLinus Torvalds } 26628df955aSTrond Myklebust } 2675c8dd29cSOlaf Kirch 2685c8dd29cSOlaf Kirch host->h_reclaiming = 0; 2695c8dd29cSOlaf Kirch up_write(&host->h_rwsem); 270d019bcf0SAdrian Bunk dprintk("NLM: done reclaiming locks for host %s\n", host->h_name); 2711da177e4SLinus Torvalds 2721da177e4SLinus Torvalds /* Now, wake up all processes that sleep on a blocked lock */ 27363185942SBryan Schumaker spin_lock(&nlm_blocked_lock); 2744f15e2b1STrond Myklebust list_for_each_entry(block, &nlm_blocked, b_list) { 2751da177e4SLinus Torvalds if (block->b_host == host) { 276e8c5c045SAl Viro block->b_status = nlm_lck_denied_grace_period; 2771da177e4SLinus Torvalds wake_up(&block->b_wait); 2781da177e4SLinus Torvalds } 2791da177e4SLinus Torvalds } 28063185942SBryan Schumaker spin_unlock(&nlm_blocked_lock); 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds /* Release host handle after use */ 2838ea6ecc8SChuck Lever nlmclnt_release_host(host); 284e3f70eadSStanislav Kinsbursky lockd_down(net); 285f25cc71eSTim Gardner kfree(req); 286df94f000SJeff Layton return 0; 2871da177e4SLinus Torvalds } 288