patch-2.4.20 linux-2.4.20/fs/jfs/namei.c

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diff -urN linux-2.4.19/fs/jfs/namei.c linux-2.4.20/fs/jfs/namei.c
@@ -0,0 +1,1441 @@
+/*
+ *   Copyright (c) International Business Machines Corp., 2000-2002
+ *   Portions Copyright (c) Christoph Hellwig, 2001-2002
+ *
+ *   This program is free software;  you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or 
+ *   (at your option) any later version.
+ * 
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program;  if not, write to the Free Software 
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include "jfs_incore.h"
+#include "jfs_inode.h"
+#include "jfs_dinode.h"
+#include "jfs_dmap.h"
+#include "jfs_unicode.h"
+#include "jfs_metapage.h"
+#include "jfs_xattr.h"
+#include "jfs_debug.h"
+
+extern struct inode_operations jfs_file_inode_operations;
+extern struct inode_operations jfs_symlink_inode_operations;
+extern struct file_operations jfs_file_operations;
+extern struct address_space_operations jfs_aops;
+
+extern int jfs_fsync(struct file *, struct dentry *, int);
+extern void jfs_truncate_nolock(struct inode *, loff_t);
+
+/*
+ * forward references
+ */
+struct inode_operations jfs_dir_inode_operations;
+struct file_operations jfs_dir_operations;
+
+s64 commitZeroLink(tid_t, struct inode *);
+
+/*
+ * NAME:	jfs_create(dip, dentry, mode)
+ *
+ * FUNCTION:	create a regular file in the parent directory <dip>
+ *		with name = <from dentry> and mode = <mode>
+ *
+ * PARAMETER:	dip 	- parent directory vnode
+ *		dentry	- dentry of new file
+ *		mode	- create mode (rwxrwxrwx).
+ *
+ * RETURN:	Errors from subroutines
+ *
+ */
+int jfs_create(struct inode *dip, struct dentry *dentry, int mode)
+{
+	int rc = 0;
+	tid_t tid;		/* transaction id */
+	struct inode *ip = NULL;	/* child directory inode */
+	ino_t ino;
+	struct component_name dname;	/* child directory name */
+	struct btstack btstack;
+	struct inode *iplist[2];
+	struct tblock *tblk;
+
+	jFYI(1, ("jfs_create: dip:0x%p name:%s\n", dip, dentry->d_name.name));
+
+	/*
+	 * search parent directory for entry/freespace
+	 * (dtSearch() returns parent directory page pinned)
+	 */
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(dip->i_sb)->nls_tab)))
+		goto out1;
+
+	/*
+	 * Either iAlloc() or txBegin() may block.  Deadlock can occur if we
+	 * block there while holding dtree page, so we allocate the inode &
+	 * begin the transaction before we search the directory.
+	 */
+	ip = ialloc(dip, mode);
+	if (ip == NULL) {
+		rc = ENOSPC;
+		goto out2;
+	}
+
+	tid = txBegin(dip->i_sb, 0);
+
+	down(&JFS_IP(dip)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	if ((rc = dtSearch(dip, &dname, &ino, &btstack, JFS_CREATE))) {
+		jERROR(1, ("jfs_create: dtSearch returned %d\n", rc));
+		goto out3;
+	}
+
+	tblk = tid_to_tblock(tid);
+	tblk->xflag |= COMMIT_CREATE;
+	tblk->ip = ip;
+
+	iplist[0] = dip;
+	iplist[1] = ip;
+
+	/*
+	 * initialize the child XAD tree root in-line in inode
+	 */
+	xtInitRoot(tid, ip);
+
+	/*
+	 * create entry in parent directory for child directory
+	 * (dtInsert() releases parent directory page)
+	 */
+	ino = ip->i_ino;
+	if ((rc = dtInsert(tid, dip, &dname, &ino, &btstack))) {
+		jERROR(1, ("jfs_create: dtInsert returned %d\n", rc));
+		if (rc == EIO)
+			txAbort(tid, 1);	/* Marks Filesystem dirty */
+		else
+			txAbort(tid, 0);	/* Filesystem full */
+		goto out3;
+	}
+
+	ip->i_op = &jfs_file_inode_operations;
+	ip->i_fop = &jfs_file_operations;
+	ip->i_mapping->a_ops = &jfs_aops;
+
+	insert_inode_hash(ip);
+	mark_inode_dirty(ip);
+	d_instantiate(dentry, ip);
+
+	dip->i_ctime = dip->i_mtime = CURRENT_TIME;
+
+	mark_inode_dirty(dip);
+
+	rc = txCommit(tid, 2, &iplist[0], 0);
+
+      out3:
+	txEnd(tid);
+	up(&JFS_IP(dip)->commit_sem);
+	up(&JFS_IP(ip)->commit_sem);
+	if (rc) {
+		ip->i_nlink = 0;
+		iput(ip);
+	}
+
+      out2:
+	free_UCSname(&dname);
+
+      out1:
+
+	jFYI(1, ("jfs_create: rc:%d\n", -rc));
+	return -rc;
+}
+
+
+/*
+ * NAME:	jfs_mkdir(dip, dentry, mode)
+ *
+ * FUNCTION:	create a child directory in the parent directory <dip>
+ *		with name = <from dentry> and mode = <mode>
+ *
+ * PARAMETER:	dip 	- parent directory vnode
+ *		dentry	- dentry of child directory
+ *		mode	- create mode (rwxrwxrwx).
+ *
+ * RETURN:	Errors from subroutines
+ *
+ * note:
+ * EACCESS: user needs search+write permission on the parent directory
+ */
+int jfs_mkdir(struct inode *dip, struct dentry *dentry, int mode)
+{
+	int rc = 0;
+	tid_t tid;		/* transaction id */
+	struct inode *ip = NULL;	/* child directory inode */
+	ino_t ino;
+	struct component_name dname;	/* child directory name */
+	struct btstack btstack;
+	struct inode *iplist[2];
+	struct tblock *tblk;
+
+	jFYI(1, ("jfs_mkdir: dip:0x%p name:%s\n", dip, dentry->d_name.name));
+
+	/* link count overflow on parent directory ? */
+	if (dip->i_nlink == JFS_LINK_MAX) {
+		rc = EMLINK;
+		goto out1;
+	}
+
+	/*
+	 * search parent directory for entry/freespace
+	 * (dtSearch() returns parent directory page pinned)
+	 */
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(dip->i_sb)->nls_tab)))
+		goto out1;
+
+	/*
+	 * Either iAlloc() or txBegin() may block.  Deadlock can occur if we
+	 * block there while holding dtree page, so we allocate the inode &
+	 * begin the transaction before we search the directory.
+	 */
+	ip = ialloc(dip, S_IFDIR | mode);
+	if (ip == NULL) {
+		rc = ENOSPC;
+		goto out2;
+	}
+
+	tid = txBegin(dip->i_sb, 0);
+
+	down(&JFS_IP(dip)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	if ((rc = dtSearch(dip, &dname, &ino, &btstack, JFS_CREATE))) {
+		jERROR(1, ("jfs_mkdir: dtSearch returned %d\n", rc));
+		goto out3;
+	}
+
+	tblk = tid_to_tblock(tid);
+	tblk->xflag |= COMMIT_CREATE;
+	tblk->ip = ip;
+
+	iplist[0] = dip;
+	iplist[1] = ip;
+
+	/*
+	 * initialize the child directory in-line in inode
+	 */
+	dtInitRoot(tid, ip, dip->i_ino);
+
+	/*
+	 * create entry in parent directory for child directory
+	 * (dtInsert() releases parent directory page)
+	 */
+	ino = ip->i_ino;
+	if ((rc = dtInsert(tid, dip, &dname, &ino, &btstack))) {
+		jERROR(1, ("jfs_mkdir: dtInsert returned %d\n", rc));
+
+		if (rc == EIO)
+			txAbort(tid, 1);	/* Marks Filesystem dirty */
+		else
+			txAbort(tid, 0);	/* Filesystem full */
+		goto out3;
+	}
+
+	ip->i_nlink = 2;	/* for '.' */
+	ip->i_op = &jfs_dir_inode_operations;
+	ip->i_fop = &jfs_dir_operations;
+	ip->i_mapping->a_ops = &jfs_aops;
+	ip->i_mapping->gfp_mask = GFP_NOFS;
+
+	insert_inode_hash(ip);
+	mark_inode_dirty(ip);
+	d_instantiate(dentry, ip);
+
+	/* update parent directory inode */
+	dip->i_nlink++;		/* for '..' from child directory */
+	dip->i_ctime = dip->i_mtime = CURRENT_TIME;
+	mark_inode_dirty(dip);
+
+	rc = txCommit(tid, 2, &iplist[0], 0);
+
+      out3:
+	txEnd(tid);
+	up(&JFS_IP(dip)->commit_sem);
+	up(&JFS_IP(ip)->commit_sem);
+	if (rc) {
+		ip->i_nlink = 0;
+		iput(ip);
+	}
+
+      out2:
+	free_UCSname(&dname);
+
+      out1:
+
+	jFYI(1, ("jfs_mkdir: rc:%d\n", -rc));
+	return -rc;
+}
+
+/*
+ * NAME:	jfs_rmdir(dip, dentry)
+ *
+ * FUNCTION:	remove a link to child directory
+ *
+ * PARAMETER:	dip 	- parent inode
+ *		dentry	- child directory dentry
+ *
+ * RETURN:	EINVAL	- if name is . or ..
+ *		EINVAL  - if . or .. exist but are invalid.
+ *		errors from subroutines
+ *
+ * note:
+ * if other threads have the directory open when the last link 
+ * is removed, the "." and ".." entries, if present, are removed before 
+ * rmdir() returns and no new entries may be created in the directory, 
+ * but the directory is not removed until the last reference to 
+ * the directory is released (cf.unlink() of regular file).
+ */
+int jfs_rmdir(struct inode *dip, struct dentry *dentry)
+{
+	int rc;
+	tid_t tid;		/* transaction id */
+	struct inode *ip = dentry->d_inode;
+	ino_t ino;
+	struct component_name dname;
+	struct inode *iplist[2];
+	struct tblock *tblk;
+
+	jFYI(1, ("jfs_rmdir: dip:0x%p name:%s\n", dip, dentry->d_name.name));
+
+	/* directory must be empty to be removed */
+	if (!dtEmpty(ip)) {
+		rc = ENOTEMPTY;
+		goto out;
+	}
+
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(dip->i_sb)->nls_tab))) {
+		goto out;
+	}
+
+	tid = txBegin(dip->i_sb, 0);
+
+	down(&JFS_IP(dip)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	iplist[0] = dip;
+	iplist[1] = ip;
+
+	tblk = tid_to_tblock(tid);
+	tblk->xflag |= COMMIT_DELETE;
+	tblk->ip = ip;
+
+	/*
+	 * delete the entry of target directory from parent directory
+	 */
+	ino = ip->i_ino;
+	if ((rc = dtDelete(tid, dip, &dname, &ino, JFS_REMOVE))) {
+		jERROR(1, ("jfs_rmdir: dtDelete returned %d\n", rc));
+		if (rc == EIO)
+			txAbort(tid, 1);
+		txEnd(tid);
+		up(&JFS_IP(dip)->commit_sem);
+		up(&JFS_IP(ip)->commit_sem);
+
+		goto out2;
+	}
+
+	/* update parent directory's link count corresponding
+	 * to ".." entry of the target directory deleted
+	 */
+	dip->i_nlink--;
+	dip->i_ctime = dip->i_mtime = CURRENT_TIME;
+	mark_inode_dirty(dip);
+
+	/*
+	 * OS/2 could have created EA and/or ACL
+	 */
+	/* free EA from both persistent and working map */
+	if (JFS_IP(ip)->ea.flag & DXD_EXTENT) {
+		/* free EA pages */
+		txEA(tid, ip, &JFS_IP(ip)->ea, NULL);
+	}
+	JFS_IP(ip)->ea.flag = 0;
+
+	/* free ACL from both persistent and working map */
+	if (JFS_IP(ip)->acl.flag & DXD_EXTENT) {
+		/* free ACL pages */
+		txEA(tid, ip, &JFS_IP(ip)->acl, NULL);
+	}
+	JFS_IP(ip)->acl.flag = 0;
+
+	/* mark the target directory as deleted */
+	ip->i_nlink = 0;
+	mark_inode_dirty(ip);
+
+	rc = txCommit(tid, 2, &iplist[0], 0);
+
+	txEnd(tid);
+
+	up(&JFS_IP(dip)->commit_sem);
+	up(&JFS_IP(ip)->commit_sem);
+
+	/*
+	 * Truncating the directory index table is not guaranteed.  It
+	 * may need to be done iteratively
+	 */
+	if (test_cflag(COMMIT_Stale, dip)) {
+		if (dip->i_size > 1)
+			jfs_truncate_nolock(dip, 0);
+
+		clear_cflag(COMMIT_Stale, dip);
+	}
+
+      out2:
+	free_UCSname(&dname);
+
+      out:
+	jFYI(1, ("jfs_rmdir: rc:%d\n", rc));
+	return -rc;
+}
+
+/*
+ * NAME:	jfs_unlink(dip, dentry)
+ *
+ * FUNCTION:	remove a link to object <vp> named by <name> 
+ *		from parent directory <dvp>
+ *
+ * PARAMETER:	dip 	- inode of parent directory
+ *		dentry 	- dentry of object to be removed
+ *
+ * RETURN:	errors from subroutines
+ *
+ * note:
+ * temporary file: if one or more processes have the file open
+ * when the last link is removed, the link will be removed before
+ * unlink() returns, but the removal of the file contents will be
+ * postponed until all references to the files are closed.
+ *
+ * JFS does NOT support unlink() on directories.
+ *
+ */
+int jfs_unlink(struct inode *dip, struct dentry *dentry)
+{
+	int rc;
+	tid_t tid;		/* transaction id */
+	struct inode *ip = dentry->d_inode;
+	ino_t ino;
+	struct component_name dname;	/* object name */
+	struct inode *iplist[2];
+	struct tblock *tblk;
+	s64 new_size = 0;
+	int commit_flag;
+
+	jFYI(1, ("jfs_unlink: dip:0x%p name:%s\n", dip, dentry->d_name.name));
+
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(dip->i_sb)->nls_tab)))
+		goto out;
+
+	IWRITE_LOCK(ip);
+
+	tid = txBegin(dip->i_sb, 0);
+
+	down(&JFS_IP(dip)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	iplist[0] = dip;
+	iplist[1] = ip;
+
+	/*
+	 * delete the entry of target file from parent directory
+	 */
+	ino = ip->i_ino;
+	if ((rc = dtDelete(tid, dip, &dname, &ino, JFS_REMOVE))) {
+		jERROR(1, ("jfs_unlink: dtDelete returned %d\n", rc));
+		if (rc == EIO)
+			txAbort(tid, 1);	/* Marks FS Dirty */
+		txEnd(tid);
+		up(&JFS_IP(dip)->commit_sem);
+		up(&JFS_IP(ip)->commit_sem);
+		IWRITE_UNLOCK(ip);
+		goto out1;
+	}
+
+	ASSERT(ip->i_nlink);
+
+	ip->i_ctime = dip->i_ctime = dip->i_mtime = CURRENT_TIME;
+	mark_inode_dirty(dip);
+
+	/* update target's inode */
+	ip->i_nlink--;
+	mark_inode_dirty(ip);
+
+	/*
+	 *      commit zero link count object
+	 */
+	if (ip->i_nlink == 0) {
+		assert(!test_cflag(COMMIT_Nolink, ip));
+		/* free block resources */
+		if ((new_size = commitZeroLink(tid, ip)) < 0) {
+			txAbort(tid, 1);	/* Marks FS Dirty */
+			txEnd(tid);
+			up(&JFS_IP(dip)->commit_sem);
+			up(&JFS_IP(ip)->commit_sem);
+			IWRITE_UNLOCK(ip);
+			rc = -new_size;		/* We return -rc */
+			goto out1;
+		}
+		tblk = tid_to_tblock(tid);
+		tblk->xflag |= COMMIT_DELETE;
+		tblk->ip = ip;
+	}
+
+	/*
+	 * Incomplete truncate of file data can
+	 * result in timing problems unless we synchronously commit the
+	 * transaction.
+	 */
+	if (new_size)
+		commit_flag = COMMIT_SYNC;
+	else
+		commit_flag = 0;
+
+	/*
+	 * If xtTruncate was incomplete, commit synchronously to avoid
+	 * timing complications
+	 */
+	rc = txCommit(tid, 2, &iplist[0], commit_flag);
+
+	txEnd(tid);
+
+	up(&JFS_IP(dip)->commit_sem);
+	up(&JFS_IP(ip)->commit_sem);
+
+
+	while (new_size && (rc == 0)) {
+		tid = txBegin(dip->i_sb, 0);
+		down(&JFS_IP(ip)->commit_sem);
+		new_size = xtTruncate_pmap(tid, ip, new_size);
+		if (new_size < 0) {
+			txAbort(tid, 1);	/* Marks FS Dirty */
+			rc = -new_size;		/* We return -rc */
+		} else
+			rc = txCommit(tid, 2, &iplist[0], COMMIT_SYNC);
+		txEnd(tid);
+		up(&JFS_IP(ip)->commit_sem);
+	}
+
+	if (ip->i_nlink == 0)
+		set_cflag(COMMIT_Nolink, ip);
+
+	if (!test_cflag(COMMIT_Holdlock, ip))
+		IWRITE_UNLOCK(ip);
+
+	/*
+	 * Truncating the directory index table is not guaranteed.  It
+	 * may need to be done iteratively
+	 */
+	if (test_cflag(COMMIT_Stale, dip)) {
+		if (dip->i_size > 1)
+			jfs_truncate_nolock(dip, 0);
+
+		clear_cflag(COMMIT_Stale, dip);
+	}
+
+      out1:
+	free_UCSname(&dname);
+      out:
+	jFYI(1, ("jfs_unlink: rc:%d\n", -rc));
+	return -rc;
+}
+
+/*
+ * NAME:	commitZeroLink()
+ *
+ * FUNCTION:    for non-directory, called by jfs_remove(),
+ *		truncate a regular file, directory or symbolic
+ *		link to zero length. return 0 if type is not 
+ *		one of these.
+ *
+ *		if the file is currently associated with a VM segment
+ *		only permanent disk and inode map resources are freed,
+ *		and neither the inode nor indirect blocks are modified
+ *		so that the resources can be later freed in the work
+ *		map by ctrunc1.
+ *		if there is no VM segment on entry, the resources are
+ *		freed in both work and permanent map.
+ *		(? for temporary file - memory object is cached even 
+ *		after no reference:
+ *		reference count > 0 -   )
+ *
+ * PARAMETERS:	cd	- pointer to commit data structure.
+ *			  current inode is the one to truncate.
+ *
+ * RETURN :	Errors from subroutines
+ */
+s64 commitZeroLink(tid_t tid, struct inode *ip)
+{
+	int filetype;
+	struct tblock *tblk;
+
+	jFYI(1, ("commitZeroLink: tid = %d, ip = 0x%p\n", tid, ip));
+
+	filetype = ip->i_mode & S_IFMT;
+	switch (filetype) {
+	case S_IFREG:
+		break;
+	case S_IFLNK:
+		/* fast symbolic link */
+		if (ip->i_size <= 256) {
+			ip->i_size = 0;
+			return 0;
+		}
+		break;
+	default:
+		assert(filetype != S_IFDIR);
+		return 0;
+	}
+
+	set_cflag(COMMIT_Freewmap, ip);
+
+	/* mark transaction of block map update type */
+	tblk = tid_to_tblock(tid);
+	tblk->xflag |= COMMIT_PMAP;
+
+	/*
+	 * free EA
+	 */
+	if (JFS_IP(ip)->ea.flag & DXD_EXTENT)
+		/* acquire maplock on EA to be freed from block map */
+		txEA(tid, ip, &JFS_IP(ip)->ea, NULL);
+
+	/*
+	 * free ACL
+	 */
+	if (JFS_IP(ip)->acl.flag & DXD_EXTENT)
+		/* acquire maplock on EA to be freed from block map */
+		txEA(tid, ip, &JFS_IP(ip)->acl, NULL);
+
+	/*
+	 * free xtree/data (truncate to zero length):
+	 * free xtree/data pages from cache if COMMIT_PWMAP, 
+	 * free xtree/data blocks from persistent block map, and
+	 * free xtree/data blocks from working block map if COMMIT_PWMAP;
+	 */
+	if (ip->i_size)
+		return xtTruncate_pmap(tid, ip, 0);
+
+	return 0;
+}
+
+
+/*
+ * NAME:	freeZeroLink()
+ *
+ * FUNCTION:    for non-directory, called by iClose(),
+ *		free resources of a file from cache and WORKING map 
+ *		for a file previously committed with zero link count
+ *		while associated with a pager object,
+ *
+ * PARAMETER:	ip	- pointer to inode of file.
+ *
+ * RETURN:	0 -ok
+ */
+int freeZeroLink(struct inode *ip)
+{
+	int rc = 0;
+	int type;
+
+	jFYI(1, ("freeZeroLink: ip = 0x%p\n", ip));
+
+	/* return if not reg or symbolic link or if size is
+	 * already ok.
+	 */
+	type = ip->i_mode & S_IFMT;
+
+	switch (type) {
+	case S_IFREG:
+		break;
+	case S_IFLNK:
+		/* if its contained in inode nothing to do */
+		if (ip->i_size <= 256)
+			return 0;
+		break;
+	default:
+		return 0;
+	}
+
+	/*
+	 * free EA
+	 */
+	if (JFS_IP(ip)->ea.flag & DXD_EXTENT) {
+		s64 xaddr = addressDXD(&JFS_IP(ip)->ea);
+		int xlen = lengthDXD(&JFS_IP(ip)->ea);
+		struct maplock maplock;	/* maplock for COMMIT_WMAP */
+		struct pxd_lock *pxdlock;	/* maplock for COMMIT_WMAP */
+
+		/* free EA pages from cache */
+		invalidate_dxd_metapages(ip, JFS_IP(ip)->ea);
+
+		/* free EA extent from working block map */
+		maplock.index = 1;
+		pxdlock = (struct pxd_lock *) & maplock;
+		pxdlock->flag = mlckFREEPXD;
+		PXDaddress(&pxdlock->pxd, xaddr);
+		PXDlength(&pxdlock->pxd, xlen);
+		txFreeMap(ip, pxdlock, 0, COMMIT_WMAP);
+	}
+
+	/*
+	 * free ACL
+	 */
+	if (JFS_IP(ip)->acl.flag & DXD_EXTENT) {
+		s64 xaddr = addressDXD(&JFS_IP(ip)->acl);
+		int xlen = lengthDXD(&JFS_IP(ip)->acl);
+		struct maplock maplock;	/* maplock for COMMIT_WMAP */
+		struct pxd_lock *pxdlock;	/* maplock for COMMIT_WMAP */
+
+		invalidate_dxd_metapages(ip, JFS_IP(ip)->acl);
+
+		/* free ACL extent from working block map */
+		maplock.index = 1;
+		pxdlock = (struct pxd_lock *) & maplock;
+		pxdlock->flag = mlckFREEPXD;
+		PXDaddress(&pxdlock->pxd, xaddr);
+		PXDlength(&pxdlock->pxd, xlen);
+		txFreeMap(ip, pxdlock, 0, COMMIT_WMAP);
+	}
+
+	/*
+	 * free xtree/data (truncate to zero length):
+	 * free xtree/data pages from cache, and
+	 * free xtree/data blocks from working block map;
+	 */
+	if (ip->i_size)
+		rc = xtTruncate(0, ip, 0, COMMIT_WMAP);
+
+	return rc;
+}
+
+/*
+ * NAME:	jfs_link(vp, dvp, name, crp)
+ *
+ * FUNCTION:	create a link to <vp> by the name = <name>
+ *		in the parent directory <dvp>
+ *
+ * PARAMETER:	vp 	- target object
+ *		dvp	- parent directory of new link
+ *		name	- name of new link to target object
+ *		crp	- credential
+ *
+ * RETURN:	Errors from subroutines
+ *
+ * note:
+ * JFS does NOT support link() on directories (to prevent circular
+ * path in the directory hierarchy);
+ * EPERM: the target object is a directory, and either the caller
+ * does not have appropriate privileges or the implementation prohibits
+ * using link() on directories [XPG4.2].
+ *
+ * JFS does NOT support links between file systems:
+ * EXDEV: target object and new link are on different file systems and
+ * implementation does not support links between file systems [XPG4.2].
+ */
+int jfs_link(struct dentry *old_dentry,
+	     struct inode *dir, struct dentry *dentry)
+{
+	int rc;
+	tid_t tid;
+	struct inode *ip = old_dentry->d_inode;
+	ino_t ino;
+	struct component_name dname;
+	struct btstack btstack;
+	struct inode *iplist[2];
+
+	jFYI(1,
+	     ("jfs_link: %s %s\n", old_dentry->d_name.name,
+	      dentry->d_name.name));
+
+	/* JFS does NOT support link() on directories */
+	if (S_ISDIR(ip->i_mode))
+		return -EPERM;
+
+	tid = txBegin(ip->i_sb, 0);
+
+	down(&JFS_IP(dir)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	if (ip->i_nlink == JFS_LINK_MAX) {
+		rc = EMLINK;
+		goto out;
+	}
+
+	/*
+	 * scan parent directory for entry/freespace
+	 */
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(ip->i_sb)->nls_tab)))
+		goto out;
+
+	if ((rc = dtSearch(dir, &dname, &ino, &btstack, JFS_CREATE)))
+		goto out;
+
+	/*
+	 * create entry for new link in parent directory
+	 */
+	ino = ip->i_ino;
+	if ((rc = dtInsert(tid, dir, &dname, &ino, &btstack)))
+		goto out;
+
+	/* update object inode */
+	ip->i_nlink++;		/* for new link */
+	ip->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(dir);
+	atomic_inc(&ip->i_count);
+	d_instantiate(dentry, ip);
+
+	iplist[0] = ip;
+	iplist[1] = dir;
+	rc = txCommit(tid, 2, &iplist[0], 0);
+
+      out:
+	txEnd(tid);
+
+	up(&JFS_IP(dir)->commit_sem);
+	up(&JFS_IP(ip)->commit_sem);
+
+	jFYI(1, ("jfs_link: rc:%d\n", rc));
+	return -rc;
+}
+
+/*
+ * NAME:	jfs_symlink(dip, dentry, name)
+ *
+ * FUNCTION:	creates a symbolic link to <symlink> by name <name>
+ *		        in directory <dip>
+ *
+ * PARAMETER:	dip	    - parent directory vnode
+ *		        dentry 	- dentry of symbolic link
+ *		        name    - the path name of the existing object 
+ *			              that will be the source of the link
+ *
+ * RETURN:	errors from subroutines
+ *
+ * note:
+ * ENAMETOOLONG: pathname resolution of a symbolic link produced
+ * an intermediate result whose length exceeds PATH_MAX [XPG4.2]
+*/
+
+int jfs_symlink(struct inode *dip, struct dentry *dentry, const char *name)
+{
+	int rc;
+	tid_t tid;
+	ino_t ino = 0;
+	struct component_name dname;
+	int ssize;		/* source pathname size */
+	struct btstack btstack;
+	struct inode *ip = dentry->d_inode;
+	unchar *i_fastsymlink;
+	s64 xlen = 0;
+	int bmask = 0, xsize;
+	s64 xaddr;
+	struct metapage *mp;
+	struct super_block *sb;
+	struct tblock *tblk;
+
+	struct inode *iplist[2];
+
+	jFYI(1, ("jfs_symlink: dip:0x%p name:%s\n", dip, name));
+
+	ssize = strlen(name) + 1;
+
+	/*
+	 * search parent directory for entry/freespace
+	 * (dtSearch() returns parent directory page pinned)
+	 */
+
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(dip->i_sb)->nls_tab)))
+		goto out1;
+
+	/*
+	 * allocate on-disk/in-memory inode for symbolic link:
+	 * (iAlloc() returns new, locked inode)
+	 */
+	ip = ialloc(dip, S_IFLNK | 0777);
+	if (ip == NULL) {
+		rc = ENOSPC;
+		goto out2;
+	}
+
+	tid = txBegin(dip->i_sb, 0);
+
+	down(&JFS_IP(dip)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	if ((rc = dtSearch(dip, &dname, &ino, &btstack, JFS_CREATE)))
+		goto out3;
+
+	tblk = tid_to_tblock(tid);
+	tblk->xflag |= COMMIT_CREATE;
+	tblk->ip = ip;
+
+	/*
+	 * create entry for symbolic link in parent directory
+	 */
+
+	ino = ip->i_ino;
+
+
+
+	if ((rc = dtInsert(tid, dip, &dname, &ino, &btstack))) {
+		jERROR(1, ("jfs_symlink: dtInsert returned %d\n", rc));
+		/* discard ne inode */
+		goto out3;
+
+	}
+
+	/* fix symlink access permission
+	 * (dir_create() ANDs in the u.u_cmask, 
+	 * but symlinks really need to be 777 access)
+	 */
+	ip->i_mode |= 0777;
+
+	/*
+	   *       write symbolic link target path name
+	 */
+	xtInitRoot(tid, ip);
+
+	/*
+	 * write source path name inline in on-disk inode (fast symbolic link)
+	 */
+
+	if (ssize <= IDATASIZE) {
+		ip->i_op = &jfs_symlink_inode_operations;
+
+		i_fastsymlink = JFS_IP(ip)->i_inline;
+		memcpy(i_fastsymlink, name, ssize);
+		ip->i_size = ssize - 1;
+
+		/*
+		 * if symlink is > 128 bytes, we don't have the space to
+		 * store inline extended attributes
+		 */
+		if (ssize > sizeof (JFS_IP(ip)->i_inline))
+			JFS_IP(ip)->mode2 &= ~INLINEEA;
+
+		jFYI(1,
+		     ("jfs_symlink: fast symlink added  ssize:%d name:%s \n",
+		      ssize, name));
+	}
+	/*
+	 * write source path name in a single extent
+	 */
+	else {
+		jFYI(1, ("jfs_symlink: allocate extent ip:0x%p\n", ip));
+
+		ip->i_op = &page_symlink_inode_operations;
+		ip->i_mapping->a_ops = &jfs_aops;
+
+		/*
+		 * even though the data of symlink object (source 
+		 * path name) is treated as non-journaled user data,
+		 * it is read/written thru buffer cache for performance.
+		 */
+		sb = ip->i_sb;
+		bmask = JFS_SBI(sb)->bsize - 1;
+		xsize = (ssize + bmask) & ~bmask;
+		xaddr = 0;
+		xlen = xsize >> JFS_SBI(sb)->l2bsize;
+		if ((rc = xtInsert(tid, ip, 0, 0, xlen, &xaddr, 0)) == 0) {
+			ip->i_size = ssize - 1;
+			while (ssize) {
+				int copy_size = min(ssize, PSIZE);
+
+				mp = get_metapage(ip, xaddr, PSIZE, 1);
+
+				if (mp == NULL) {
+					dtDelete(tid, dip, &dname, &ino,
+						 JFS_REMOVE);
+					rc = EIO;
+					goto out3;
+				}
+				memcpy(mp->data, name, copy_size);
+				flush_metapage(mp);
+#if 0
+				mark_buffer_uptodate(bp, 1);
+				mark_buffer_dirty(bp, 1);
+				if (IS_SYNC(dip)) {
+					ll_rw_block(WRITE, 1, &bp);
+					wait_on_buffer(bp);
+				}
+				brelse(bp);
+#endif				/* 0 */
+				ssize -= copy_size;
+				xaddr += JFS_SBI(sb)->nbperpage;
+			}
+			ip->i_blocks = LBLK2PBLK(sb, xlen);
+		} else {
+			dtDelete(tid, dip, &dname, &ino, JFS_REMOVE);
+			rc = ENOSPC;
+			goto out3;
+		}
+	}
+
+	insert_inode_hash(ip);
+	mark_inode_dirty(ip);
+	d_instantiate(dentry, ip);
+
+	/*
+	 * commit update of parent directory and link object
+	 *
+	 * if extent allocation failed (ENOSPC),
+	 * the parent inode is committed regardless to avoid
+	 * backing out parent directory update (by dtInsert())
+	 * and subsequent dtDelete() which is harmless wrt 
+	 * integrity concern.  
+	 * the symlink inode will be freed by iput() at exit
+	 * as it has a zero link count (by dtDelete()) and 
+	 * no permanant resources. 
+	 */
+
+	iplist[0] = dip;
+	if (rc == 0) {
+		iplist[1] = ip;
+		rc = txCommit(tid, 2, &iplist[0], 0);
+	} else
+		rc = txCommit(tid, 1, &iplist[0], 0);
+
+      out3:
+	txEnd(tid);
+	up(&JFS_IP(dip)->commit_sem);
+	up(&JFS_IP(ip)->commit_sem);
+	if (rc) {
+		ip->i_nlink = 0;
+		iput(ip);
+	}
+
+      out2:
+	free_UCSname(&dname);
+
+      out1:
+	jFYI(1, ("jfs_symlink: rc:%d\n", -rc));
+	return -rc;
+}
+
+
+/*
+ * NAME:        jfs_rename
+ *
+ * FUNCTION:    rename a file or directory
+ */
+int jfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+	       struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct btstack btstack;
+	ino_t ino;
+	struct component_name new_dname;
+	struct inode *new_ip;
+	struct component_name old_dname;
+	struct inode *old_ip;
+	int rc;
+	tid_t tid;
+	struct tlock *tlck;
+	struct dt_lock *dtlck;
+	struct lv *lv;
+	int ipcount;
+	struct inode *iplist[4];
+	struct tblock *tblk;
+	s64 new_size = 0;
+	int commit_flag;
+
+
+	jFYI(1,
+	     ("jfs_rename: %s %s\n", old_dentry->d_name.name,
+	      new_dentry->d_name.name));
+
+	old_ip = old_dentry->d_inode;
+	new_ip = new_dentry->d_inode;
+
+	if ((rc = get_UCSname(&old_dname, old_dentry,
+			      JFS_SBI(old_dir->i_sb)->nls_tab)))
+		goto out1;
+
+	if ((rc = get_UCSname(&new_dname, new_dentry,
+			      JFS_SBI(old_dir->i_sb)->nls_tab)))
+		goto out2;
+
+	/*
+	 * Make sure source inode number is what we think it is
+	 */
+	rc = dtSearch(old_dir, &old_dname, &ino, &btstack, JFS_LOOKUP);
+	if (rc || (ino != old_ip->i_ino)) {
+		rc = ENOENT;
+		goto out3;
+	}
+
+	/*
+	 * Make sure dest inode number (if any) is what we think it is
+	 */
+	rc = dtSearch(new_dir, &new_dname, &ino, &btstack, JFS_LOOKUP);
+	if (rc == 0) {
+		if ((new_ip == 0) || (ino != new_ip->i_ino)) {
+			rc = ESTALE;
+			goto out3;
+		}
+	} else if (rc != ENOENT)
+		goto out3;
+	else if (new_ip) {
+		/* no entry exists, but one was expected */
+		rc = ESTALE;
+		goto out3;
+	}
+
+	if (S_ISDIR(old_ip->i_mode)) {
+		if (new_ip) {
+			if (!dtEmpty(new_ip)) {
+				rc = ENOTEMPTY;
+				goto out3;
+			}
+		} else if ((new_dir != old_dir) &&
+			   (new_dir->i_nlink == JFS_LINK_MAX)) {
+			rc = EMLINK;
+			goto out3;
+		}
+	} else if (new_ip)
+		IWRITE_LOCK(new_ip);
+
+	/*
+	 * The real work starts here
+	 */
+	tid = txBegin(new_dir->i_sb, 0);
+
+	down(&JFS_IP(new_dir)->commit_sem);
+	down(&JFS_IP(old_ip)->commit_sem);
+	if (old_dir != new_dir)
+		down(&JFS_IP(old_dir)->commit_sem);
+
+	if (new_ip) {
+		down(&JFS_IP(new_ip)->commit_sem);
+		/*
+		 * Change existing directory entry to new inode number
+		 */
+		ino = new_ip->i_ino;
+		rc = dtModify(tid, new_dir, &new_dname, &ino,
+			      old_ip->i_ino, JFS_RENAME);
+		if (rc)
+			goto out4;
+		new_ip->i_nlink--;
+		if (S_ISDIR(new_ip->i_mode)) {
+			new_ip->i_nlink--;
+			assert(new_ip->i_nlink == 0);
+			tblk = tid_to_tblock(tid);
+			tblk->xflag |= COMMIT_DELETE;
+			tblk->ip = new_ip;
+		} else if (new_ip->i_nlink == 0) {
+			assert(!test_cflag(COMMIT_Nolink, new_ip));
+			/* free block resources */
+			if ((new_size = commitZeroLink(tid, new_ip)) < 0) {
+				txAbort(tid, 1);	/* Marks FS Dirty */
+				rc = -new_size;		/* We return -rc */
+				goto out4;
+			}
+			tblk = tid_to_tblock(tid);
+			tblk->xflag |= COMMIT_DELETE;
+			tblk->ip = new_ip;
+		} else {
+			new_ip->i_ctime = CURRENT_TIME;
+			mark_inode_dirty(new_ip);
+		}
+	} else {
+		/*
+		 * Add new directory entry
+		 */
+		rc = dtSearch(new_dir, &new_dname, &ino, &btstack,
+			      JFS_CREATE);
+		if (rc) {
+			jERROR(1,
+			       ("jfs_rename didn't expect dtSearch to fail w/rc = %d\n",
+				rc));
+			goto out4;
+		}
+
+		ino = old_ip->i_ino;
+		rc = dtInsert(tid, new_dir, &new_dname, &ino, &btstack);
+		if (rc) {
+			jERROR(1,
+			       ("jfs_rename: dtInsert failed w/rc = %d\n",
+				rc));
+			goto out4;
+		}
+		if (S_ISDIR(old_ip->i_mode))
+			new_dir->i_nlink++;
+	}
+	/*
+	 * Remove old directory entry
+	 */
+
+	ino = old_ip->i_ino;
+	rc = dtDelete(tid, old_dir, &old_dname, &ino, JFS_REMOVE);
+	if (rc) {
+		jERROR(1,
+		       ("jfs_rename did not expect dtDelete to return rc = %d\n",
+			rc));
+		txAbort(tid, 1);	/* Marks Filesystem dirty */
+		goto out4;
+	}
+	if (S_ISDIR(old_ip->i_mode)) {
+		old_dir->i_nlink--;
+		if (old_dir != new_dir) {
+			/*
+			 * Change inode number of parent for moved directory
+			 */
+
+			JFS_IP(old_ip)->i_dtroot.header.idotdot =
+				cpu_to_le32(new_dir->i_ino);
+
+			/* Linelock header of dtree */
+			tlck = txLock(tid, old_ip,
+				    (struct metapage *) &JFS_IP(old_ip)->bxflag,
+				      tlckDTREE | tlckBTROOT);
+			dtlck = (struct dt_lock *) & tlck->lock;
+			ASSERT(dtlck->index == 0);
+			lv = & dtlck->lv[0];
+			lv->offset = 0;
+			lv->length = 1;
+			dtlck->index++;
+		}
+	}
+
+	/*
+	 * Update ctime on changed/moved inodes & mark dirty
+	 */
+	old_ip->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(old_ip);
+
+	new_dir->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(new_dir);
+
+	/* Build list of inodes modified by this transaction */
+	ipcount = 0;
+	iplist[ipcount++] = old_ip;
+	if (new_ip)
+		iplist[ipcount++] = new_ip;
+	iplist[ipcount++] = old_dir;
+
+	if (old_dir != new_dir) {
+		iplist[ipcount++] = new_dir;
+		old_dir->i_ctime = CURRENT_TIME;
+		mark_inode_dirty(old_dir);
+	}
+
+	/*
+	 * Incomplete truncate of file data can
+	 * result in timing problems unless we synchronously commit the
+	 * transaction.
+	 */
+	if (new_size)
+		commit_flag = COMMIT_SYNC;
+	else
+		commit_flag = 0;
+
+	rc = txCommit(tid, ipcount, iplist, commit_flag);
+
+	/*
+	 * Don't unlock new_ip if COMMIT_HOLDLOCK is set
+	 */
+	if (new_ip && test_cflag(COMMIT_Holdlock, new_ip)) {
+		up(&JFS_IP(new_ip)->commit_sem);
+		new_ip = 0;
+	}
+
+      out4:
+	txEnd(tid);
+
+	up(&JFS_IP(new_dir)->commit_sem);
+	up(&JFS_IP(old_ip)->commit_sem);
+	if (old_dir != new_dir)
+		up(&JFS_IP(old_dir)->commit_sem);
+	if (new_ip)
+		up(&JFS_IP(new_ip)->commit_sem);
+
+	while (new_size && (rc == 0)) {
+		tid = txBegin(new_ip->i_sb, 0);
+		down(&JFS_IP(new_ip)->commit_sem);
+		new_size = xtTruncate_pmap(tid, new_ip, new_size);
+		if (new_size < 0) {
+			txAbort(tid, 1);
+			rc = -new_size;		/* We return -rc */
+		} else
+			rc = txCommit(tid, 1, &new_ip, COMMIT_SYNC);
+		txEnd(tid);
+		up(&JFS_IP(new_ip)->commit_sem);
+	}
+	if (new_ip && (new_ip->i_nlink == 0))
+		set_cflag(COMMIT_Nolink, new_ip);
+      out3:
+	free_UCSname(&new_dname);
+      out2:
+	free_UCSname(&old_dname);
+      out1:
+	if (new_ip && !S_ISDIR(new_ip->i_mode))
+		IWRITE_UNLOCK(new_ip);
+	/*
+	 * Truncating the directory index table is not guaranteed.  It
+	 * may need to be done iteratively
+	 */
+	if (test_cflag(COMMIT_Stale, old_dir)) {
+		if (old_dir->i_size > 1)
+			jfs_truncate_nolock(old_dir, 0);
+
+		clear_cflag(COMMIT_Stale, old_dir);
+	}
+
+	jFYI(1, ("jfs_rename: returning %d\n", rc));
+	return -rc;
+}
+
+
+/*
+ * NAME:        jfs_mknod
+ *
+ * FUNCTION:    Create a special file (device)
+ */
+int jfs_mknod(struct inode *dir, struct dentry *dentry, int mode, int rdev)
+{
+	struct btstack btstack;
+	struct component_name dname;
+	ino_t ino;
+	struct inode *ip;
+	struct inode *iplist[2];
+	int rc;
+	tid_t tid;
+	struct tblock *tblk;
+
+	jFYI(1, ("jfs_mknod: %s\n", dentry->d_name.name));
+
+	if ((rc = get_UCSname(&dname, dentry, JFS_SBI(dir->i_sb)->nls_tab)))
+		goto out;
+
+	ip = ialloc(dir, mode);
+	if (ip == NULL) {
+		rc = ENOSPC;
+		goto out1;
+	}
+
+	tid = txBegin(dir->i_sb, 0);
+
+	down(&JFS_IP(dir)->commit_sem);
+	down(&JFS_IP(ip)->commit_sem);
+
+	if ((rc = dtSearch(dir, &dname, &ino, &btstack, JFS_CREATE)))
+		goto out3;
+
+	tblk = tid_to_tblock(tid);
+	tblk->xflag |= COMMIT_CREATE;
+	tblk->ip = ip;
+
+	ino = ip->i_ino;
+	if ((rc = dtInsert(tid, dir, &dname, &ino, &btstack)))
+		goto out3;
+
+	ip->i_op = &jfs_file_inode_operations;
+	init_special_inode(ip, ip->i_mode, rdev);
+
+	insert_inode_hash(ip);
+	mark_inode_dirty(ip);
+	d_instantiate(dentry, ip);
+
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+
+	mark_inode_dirty(dir);
+
+	iplist[0] = dir;
+	iplist[1] = ip;
+	rc = txCommit(tid, 2, iplist, 0);
+
+      out3:
+	txEnd(tid);
+	up(&JFS_IP(ip)->commit_sem);
+	up(&JFS_IP(dir)->commit_sem);
+	if (rc) {
+		ip->i_nlink = 0;
+		iput(ip);
+	}
+
+      out1:
+	free_UCSname(&dname);
+
+      out:
+	jFYI(1, ("jfs_mknod: returning %d\n", rc));
+	return -rc;
+}
+
+static struct dentry *jfs_lookup(struct inode *dip, struct dentry *dentry)
+{
+	struct btstack btstack;
+	ino_t inum;
+	struct inode *ip;
+	struct component_name key;
+	const char *name = dentry->d_name.name;
+	int len = dentry->d_name.len;
+	int rc;
+
+	jFYI(1, ("jfs_lookup: name = %s\n", name));
+
+
+	if ((name[0] == '.') && (len == 1))
+		inum = dip->i_ino;
+	else if (strcmp(name, "..") == 0)
+		inum = PARENT(dip);
+	else {
+		if ((rc =
+		     get_UCSname(&key, dentry, JFS_SBI(dip->i_sb)->nls_tab)))
+			return ERR_PTR(-rc);
+		rc = dtSearch(dip, &key, &inum, &btstack, JFS_LOOKUP);
+		free_UCSname(&key);
+		if (rc == ENOENT) {
+			d_add(dentry, NULL);
+			return ERR_PTR(0);
+		} else if (rc) {
+			jERROR(1,
+			       ("jfs_lookup: dtSearch returned %d\n", rc));
+			return ERR_PTR(-rc);
+		}
+	}
+
+	ip = iget(dip->i_sb, inum);
+	if (ip == NULL) {
+		jERROR(1,
+		       ("jfs_lookup: iget failed on inum %d\n",
+			(uint) inum));
+		return ERR_PTR(-EACCES);
+	}
+
+	d_add(dentry, ip);
+
+	return ERR_PTR(0);
+}
+
+struct inode_operations jfs_dir_inode_operations = {
+	.create		= jfs_create,
+	.lookup		= jfs_lookup,
+	.link		= jfs_link,
+	.unlink		= jfs_unlink,
+	.symlink	= jfs_symlink,
+	.mkdir		= jfs_mkdir,
+	.rmdir		= jfs_rmdir,
+	.mknod		= jfs_mknod,
+	.rename		= jfs_rename,
+	.setxattr	= jfs_setxattr,
+	.getxattr	= jfs_getxattr,
+	.listxattr	= jfs_listxattr,
+	.removexattr	= jfs_removexattr,
+};
+
+struct file_operations jfs_dir_operations = {
+	.read		= generic_read_dir,
+	.readdir	= jfs_readdir,
+	.fsync		= jfs_fsync,
+};
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)