patch-2.1.32 linux/fs/lockd/svcsubs.c

• Lines: 279
• Date: Fri Apr 4 11:06:05 1997
• Orig file: v2.1.31/linux/fs/lockd/svcsubs.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.31/linux/fs/lockd/svcsubs.c linux/fs/lockd/svcsubs.c
@@ -0,0 +1,278 @@
+/*
+ * linux/fs/lockd/svcsubs.c
+ *
+ * Various support routines for the NLM server.
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/in.h>
+#include <linux/sunrpc/svc.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfsd/nfsfh.h>
+#include <linux/nfsd/export.h>
+#include <linux/lockd/lockd.h>
+#include <linux/lockd/share.h>
+#include <linux/lockd/sm_inter.h>
+
+#define NLMDBG_FACILITY		NLMDBG_SVCSUBS
+
+
+/*
+ * Global file hash table
+ */
+#define FILE_NRHASH		32
+#define FILE_HASH(dev, ino)	(((dev) + (ino)) & FILE_NRHASH)
+static struct nlm_file *	nlm_files[FILE_NRHASH];
+static struct semaphore		nlm_file_sema = MUTEX;
+
+/*
+ * Lookup file info. If it doesn't exist, create a file info struct
+ * and open a (VFS) file for the given inode.
+ *
+ * FIXME:
+ * Note that we open the file O_RDONLY even when creating write locks.
+ * This is not quite right, but for now, we assume the client performs
+ * the proper R/W checking.
+ */
+u32
+nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
+					struct nfs_fh *f)
+{
+	struct nlm_file	*file;
+	struct knfs_fh	*fh = (struct knfs_fh *) f;
+	unsigned int	hash = FILE_HASH(fh->fh_dev, fh->fh_ino);
+	u32		nfserr;
+
+	dprintk("lockd: nlm_file_lookup(%04x/%ld)\n", fh->fh_dev, fh->fh_ino);
+
+	/* Lock file table */
+	down(&nlm_file_sema);
+
+	for (file = nlm_files[hash]; file; file = file->f_next) {
+		if (file->f_handle.fh_ino == fh->fh_ino
+		 && !memcmp(&file->f_handle, fh, sizeof(*fh)))
+			goto found;
+	}
+
+	dprintk("lockd: creating file for %04x/%ld\n", fh->fh_dev, fh->fh_ino);
+	if (!(file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL))) {
+		up(&nlm_file_sema);
+		return nlm_lck_denied_nolocks;
+	}
+
+	memset(file, 0, sizeof(*file));
+	file->f_handle = *fh;
+	file->f_sema   = MUTEX;
+
+	/* Open the file. Note that this must not sleep for too long, else
+	 * we would lock up lockd:-) So no NFS re-exports, folks. */
+	if ((nfserr = nlmsvc_ops->fopen(rqstp, fh, &file->f_file)) != 0) {
+		dprintk("lockd: open failed (nfserr %ld)\n", ntohl(nfserr));
+		kfree(file);
+		up(&nlm_file_sema);
+		return nlm_lck_denied;
+	}
+
+	file->f_next = nlm_files[hash];
+	nlm_files[hash] = file;
+
+found:
+	dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
+	*result = file;
+	up(&nlm_file_sema);
+	file->f_count++;
+	return 0;
+}
+
+/*
+ * Delete a file after having released all locks, blocks and shares
+ */
+static inline void
+nlm_delete_file(struct nlm_file *file)
+{
+	struct inode	*inode = nlmsvc_file_inode(file);
+	struct nlm_file	**fp, *f;
+
+	dprintk("lockd: closing file %04x/%ld\n", inode->i_dev, inode->i_ino);
+	fp = nlm_files + FILE_HASH(inode->i_dev, inode->i_ino);
+	while ((f = *fp) != NULL) {
+		if (f == file) {
+			*fp = file->f_next;
+			nlmsvc_ops->fclose(&file->f_file);
+			kfree(file);
+			return;
+		}
+		fp = &file->f_next;
+	}
+
+	printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
+}
+
+/*
+ * Loop over all locks on the given file and perform the specified
+ * action.
+ */
+static int
+nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
+{
+	struct inode	 *inode = nlmsvc_file_inode(file);
+	struct file_lock *fl;
+	struct nlm_host	 *lockhost;
+
+again:
+	file->f_locks = 0;
+	for (fl = inode->i_flock; fl; fl = fl->fl_next) {
+		if (!(fl->fl_flags & FL_LOCKD))
+			continue;
+
+		/* update current lock count */
+		file->f_locks++;
+		lockhost = (struct nlm_host *) fl->fl_owner;
+		if (action == NLM_ACT_MARK)
+			lockhost->h_inuse = 1;
+		else if (action == NLM_ACT_CHECK)
+			return 1;
+		else if (action == NLM_ACT_UNLOCK) {
+			struct file_lock lock = *fl;
+
+			if (host && lockhost != host)
+				continue;
+
+			lock.fl_type  = F_UNLCK;
+			lock.fl_start = 0;
+			lock.fl_end   = NLM_OFFSET_MAX;
+			if (posix_lock_file(&file->f_file, &lock, 0) < 0) {
+				printk("lockd: unlock failure in %s:%d\n",
+						__FILE__, __LINE__);
+				return 1;
+			}
+			goto again;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Operate on a single file
+ */
+static inline int
+nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
+{
+	if (action == NLM_ACT_CHECK) {
+		/* Fast path for mark and sweep garbage collection */
+		if (file->f_count || file->f_blocks || file->f_shares)
+			return 1;
+	} else {
+		if (nlmsvc_traverse_blocks(host, file, action)
+		 || nlmsvc_traverse_shares(host, file, action))
+			return 1;
+	}
+	return nlm_traverse_locks(host, file, action);
+}
+
+/*
+ * Loop over all files in the file table.
+ */
+static int
+nlm_traverse_files(struct nlm_host *host, int action)
+{
+	struct nlm_file	*file, **fp;
+	int		i;
+
+	down(&nlm_file_sema);
+	for (i = 0; i < FILE_NRHASH; i++) {
+		fp = nlm_files + i;
+		while ((file = *fp) != NULL) {
+			/* Traverse locks, blocks and shares of this file
+			 * and update file->f_locks count */
+			if (nlm_inspect_file(host, file, action)) {
+				up(&nlm_file_sema);
+				return 1;
+			}
+
+			/* No more references to this file. Let go of it. */
+			if (!file->f_blocks && !file->f_locks
+			 && !file->f_shares && !file->f_count) {
+				*fp = file->f_next;
+				nlmsvc_ops->fclose(&file->f_file);
+				kfree(file);
+			} else {
+				fp = &file->f_next;
+			}
+		}
+	}
+	up(&nlm_file_sema);
+	return 0;
+}
+
+/*
+ * Release file. If there are no more remote locks on this file,
+ * close it and free the handle.
+ *
+ * Note that we can't do proper reference counting without major
+ * contortions because the code in fs/locks.c creates, deletes and
+ * splits locks without notification. Our only way is to walk the
+ * entire lock list each time we remove a lock.
+ */
+void
+nlm_release_file(struct nlm_file *file)
+{
+	dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
+				file, file->f_count);
+
+	/* Lock file table */
+	down(&nlm_file_sema);
+
+	/* If there are no more locks etc, delete the file */
+	if (--(file->f_count) == 0
+	 && !nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
+		nlm_delete_file(file);
+
+	up(&nlm_file_sema);
+	return;
+}
+
+/*
+ * Mark all hosts that still hold resources
+ */
+void
+nlmsvc_mark_resources(void)
+{
+	dprintk("lockd: nlmsvc_mark_resources\n");
+
+	nlm_traverse_files(NULL, NLM_ACT_MARK);
+}
+
+/*
+ * Release all resources held by the given client
+ */
+void
+nlmsvc_free_host_resources(struct nlm_host *host)
+{
+	dprintk("lockd: nlmsvc_free_host_resources\n");
+
+	if (nlm_traverse_files(host, NLM_ACT_UNLOCK))
+		printk(KERN_WARNING
+			"lockd: couldn't remove all locks held by %s",
+			host->h_name);
+}
+
+/*
+ * Delete a client when the nfsd entry is removed.
+ */
+void
+nlmsvc_invalidate_client(struct svc_client *clnt)
+{
+	struct nlm_host	*host;
+
+	if ((host = nlm_lookup_host(clnt, NULL, 0, 0)) != NULL) {
+		dprintk("lockd: invalidating client for %s\n", host->h_name);
+		nlmsvc_free_host_resources(host);
+		host->h_expires = 0;
+		nlm_release_host(host);
+	}
+}