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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/lockd/clntlock.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/lockd/clntlock.c')
-rw-r--r--fs/lockd/clntlock.c245
1 files changed, 245 insertions, 0 deletions
diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
new file mode 100644
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+++ b/fs/lockd/clntlock.c
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+/*
+ * 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 = &block;
+
+ /* 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);
+}