diff options
Diffstat (limited to 'fs/lockd/clntlock.c')
| -rw-r--r-- | fs/lockd/clntlock.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c new file mode 100644 index 0000000..ef7103b --- /dev/null +++ b/fs/lockd/clntlock.c @@ -0,0 +1,245 @@ +/* + * linux/fs/lockd/clntlock.c + * + * Lock handling for the client side NLM implementation + * + * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/time.h> +#include <linux/nfs_fs.h> +#include <linux/sunrpc/clnt.h> +#include <linux/sunrpc/svc.h> +#include <linux/lockd/lockd.h> +#include <linux/smp_lock.h> + +#define NLMDBG_FACILITY NLMDBG_CLIENT + +/* + * Local function prototypes + */ +static int reclaimer(void *ptr); + +/* + * The following functions handle blocking and granting from the + * client perspective. + */ + +/* + * This is the representation of a blocked client lock. + */ +struct nlm_wait { + struct nlm_wait * b_next; /* linked list */ + wait_queue_head_t b_wait; /* where to wait on */ + struct nlm_host * b_host; + struct file_lock * b_lock; /* local file lock */ + unsigned short b_reclaim; /* got to reclaim lock */ + u32 b_status; /* grant callback status */ +}; + +static struct nlm_wait * nlm_blocked; + +/* + * Block on a lock + */ +int +nlmclnt_block(struct nlm_host *host, struct file_lock *fl, u32 *statp) +{ + struct nlm_wait block, **head; + int err; + u32 pstate; + + block.b_host = host; + block.b_lock = fl; + init_waitqueue_head(&block.b_wait); + block.b_status = NLM_LCK_BLOCKED; + block.b_next = nlm_blocked; + nlm_blocked = █ + + /* Remember pseudo nsm state */ + pstate = host->h_state; + + /* Go to sleep waiting for GRANT callback. Some servers seem + * to lose callbacks, however, so we're going to poll from + * time to time just to make sure. + * + * For now, the retry frequency is pretty high; normally + * a 1 minute timeout would do. See the comment before + * nlmclnt_lock for an explanation. + */ + sleep_on_timeout(&block.b_wait, 30*HZ); + + for (head = &nlm_blocked; *head; head = &(*head)->b_next) { + if (*head == &block) { + *head = block.b_next; + break; + } + } + + if (!signalled()) { + *statp = block.b_status; + return 0; + } + + /* Okay, we were interrupted. Cancel the pending request + * unless the server has rebooted. + */ + if (pstate == host->h_state && (err = nlmclnt_cancel(host, fl)) < 0) + printk(KERN_NOTICE + "lockd: CANCEL call failed (errno %d)\n", -err); + + return -ERESTARTSYS; +} + +/* + * The server lockd has called us back to tell us the lock was granted + */ +u32 +nlmclnt_grant(struct nlm_lock *lock) +{ + struct nlm_wait *block; + + /* + * Look up blocked request based on arguments. + * Warning: must not use cookie to match it! + */ + for (block = nlm_blocked; block; block = block->b_next) { + if (nlm_compare_locks(block->b_lock, &lock->fl)) + break; + } + + /* Ooops, no blocked request found. */ + if (block == NULL) + return nlm_lck_denied; + + /* Alright, we found the lock. Set the return status and + * wake up the caller. + */ + block->b_status = NLM_LCK_GRANTED; + wake_up(&block->b_wait); + + return nlm_granted; +} + +/* + * The following procedures deal with the recovery of locks after a + * server crash. + */ + +/* + * Mark the locks for reclaiming. + * FIXME: In 2.5 we don't want to iterate through any global file_lock_list. + * Maintain NLM lock reclaiming lists in the nlm_host instead. + */ +static +void nlmclnt_mark_reclaim(struct nlm_host *host) +{ + struct file_lock *fl; + struct inode *inode; + struct list_head *tmp; + + list_for_each(tmp, &file_lock_list) { + fl = list_entry(tmp, struct file_lock, fl_link); + + inode = fl->fl_file->f_dentry->d_inode; + if (inode->i_sb->s_magic != NFS_SUPER_MAGIC) + continue; + if (fl->fl_u.nfs_fl.owner->host != host) + continue; + if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_GRANTED)) + continue; + fl->fl_u.nfs_fl.flags |= NFS_LCK_RECLAIM; + } +} + +/* + * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number, + * that we mark locks for reclaiming, and that we bump the pseudo NSM state. + */ +static inline +void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate) +{ + host->h_monitored = 0; + host->h_nsmstate = newstate; + host->h_state++; + host->h_nextrebind = 0; + nlm_rebind_host(host); + nlmclnt_mark_reclaim(host); + dprintk("NLM: reclaiming locks for host %s", host->h_name); +} + +/* + * Reclaim all locks on server host. We do this by spawning a separate + * reclaimer thread. + */ +void +nlmclnt_recovery(struct nlm_host *host, u32 newstate) +{ + if (host->h_reclaiming++) { + if (host->h_nsmstate == newstate) + return; + nlmclnt_prepare_reclaim(host, newstate); + } else { + nlmclnt_prepare_reclaim(host, newstate); + nlm_get_host(host); + __module_get(THIS_MODULE); + if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0) + module_put(THIS_MODULE); + } +} + +static int +reclaimer(void *ptr) +{ + struct nlm_host *host = (struct nlm_host *) ptr; + struct nlm_wait *block; + struct list_head *tmp; + struct file_lock *fl; + struct inode *inode; + + daemonize("%s-reclaim", host->h_name); + allow_signal(SIGKILL); + + /* This one ensures that our parent doesn't terminate while the + * reclaim is in progress */ + lock_kernel(); + lockd_up(); + + /* First, reclaim all locks that have been marked. */ +restart: + list_for_each(tmp, &file_lock_list) { + fl = list_entry(tmp, struct file_lock, fl_link); + + inode = fl->fl_file->f_dentry->d_inode; + if (inode->i_sb->s_magic != NFS_SUPER_MAGIC) + continue; + if (fl->fl_u.nfs_fl.owner->host != host) + continue; + if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM)) + continue; + + fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM; + nlmclnt_reclaim(host, fl); + if (signalled()) + break; + goto restart; + } + + host->h_reclaiming = 0; + + /* Now, wake up all processes that sleep on a blocked lock */ + for (block = nlm_blocked; block; block = block->b_next) { + if (block->b_host == host) { + block->b_status = NLM_LCK_DENIED_GRACE_PERIOD; + wake_up(&block->b_wait); + } + } + + /* Release host handle after use */ + nlm_release_host(host); + lockd_down(); + unlock_kernel(); + module_put_and_exit(0); +} |
