[PATCH 38/67] aufs handling file/dir, and address_space operation

[hooanon05@yahoo.co.jp]

From: Junjiro Okajima <hooanon05@yahoo.co.jp>

	initial commit
	aufs handling file/dir, and address_space operation

Signed-off-by: Junjiro Okajima <hooanon05@yahoo.co.jp>
---
 fs/aufs/file.c |  822 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 822 insertions(+), 0 deletions(-)

diff --git a/fs/aufs/file.c b/fs/aufs/file.c
new file mode 100644
index 0000000..d4396d3
--- /dev/null
+++ b/fs/aufs/file.c
@@ -0,0 +1,822 @@
+/*
+ * Copyright (C) 2005-2008 Junjiro Okajima
+ *
+ * This program, aufs 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * handling file/dir, and address_space operation
+ *
+ * $Id: file.c,v 1.4 2008/05/04 23:54:53 sfjro Exp $
+ */
+
+//#include <linux/fsnotify.h>
+#include <linux/pagemap.h>
+//#include <linux/poll.h>
+//#include <linux/security.h>
+#include "aufs.h"
+
+/*
+ * a dirty trick for handling FMODE_EXEC and deny_write_access().
+ * because FMODE_EXEC flag is not passed to f_op->open(),
+ * set it to file->private_data temporary.
+ */
+#if !defined(CONFIG_AUFS_MODULE) || defined(CONFIG_AUFS_DENY_WRITE_ACCESS_PATCH)
+int au_store_fmode_exec(struct nameidata *nd, struct inode *inode)
+{
+	int err;
+	union {
+		void *p;
+		unsigned long ul;
+	} u;
+
+	err = 0;
+	if (nd
+	    && (nd->flags & LOOKUP_OPEN)
+	    && nd->intent.open.file
+	    && (nd->intent.open.flags & FMODE_EXEC)
+	    && inode
+	    && S_ISREG(inode->i_mode)) {
+		u.ul = nd->intent.open.flags;
+		nd->intent.open.file->private_data = u.p;
+		//smp_mb();
+		err = 1;
+	}
+
+	return err;
+}
+#endif
+
+/* drop flags for writing */
+unsigned int au_file_roflags(unsigned int flags)
+{
+	flags &= ~(O_WRONLY | O_RDWR | O_APPEND | O_CREAT | O_TRUNC);
+	flags |= O_RDONLY | O_NOATIME;
+	return flags;
+}
+
+/* common functions to regular file and dir */
+struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
+		       struct file *file)
+{
+	struct file *h_file;
+	struct dentry *h_dentry;
+	struct inode *h_inode;
+	struct super_block *sb;
+	struct au_branch *br;
+	int hinotify, err;
+
+	LKTRTrace("%.*s, b%d, flags 0%o, f %d\n",
+		  AuDLNPair(dentry), bindex, flags, !!file);
+	AuDebugOn(!dentry);
+	h_dentry = au_h_dptr(dentry, bindex);
+	AuDebugOn(!h_dentry);
+	h_inode = h_dentry->d_inode;
+	AuDebugOn(!h_inode);
+
+	sb = dentry->d_sb;
+	hinotify = !!au_opt_test(au_mntflags(sb), UDBA_INOTIFY);
+#if 0
+	if (unlikely(hinotify))
+		test here?
+#endif
+
+	br = au_sbr(sb, bindex);
+	au_br_get(br);
+	/* drop flags for writing */
+	if (au_test_ro(sb, bindex, dentry->d_inode))
+		flags = au_file_roflags(flags);
+	flags &= ~O_CREAT;
+
+	h_file = NULL;
+	if (unlikely(file && au_test_nfs(h_dentry->d_sb)))
+		h_file = au_h_intent(dentry, bindex, file);
+	if (!h_file) {
+		//DbgSleep(3);
+		h_file = dentry_open(dget(h_dentry), mntget(br->br_mnt), flags);
+		//if (LktrCond) {fput(h_file); h_file = ERR_PTR(-1);}
+	}
+
+	/*
+	 * a dirty trick for handling FMODE_EXEC and deny_write_access().
+	 */
+	if (file && (file->f_mode & FMODE_EXEC)) {
+		h_file->f_mode |= FMODE_EXEC;
+		smp_mb(); /* flush f_mode */
+		err = au_deny_write_access(h_file);
+		if (unlikely(err)) {
+			fput(h_file);
+			h_file = ERR_PTR(err);
+		}
+	}
+	if (!IS_ERR(h_file))
+		return h_file;
+
+	au_br_put(br);
+	AuTraceErrPtr(h_file);
+	return h_file;
+}
+
+static int do_coo(struct dentry *dentry, aufs_bindex_t bstart)
+{
+	int err;
+	struct dentry *parent, *h_parent, *h_dentry, *gparent;
+	aufs_bindex_t bcpup;
+	struct inode *h_dir, *h_inode, *dir;
+	struct super_block *sb;
+
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+	AuDebugOn(IS_ROOT(dentry));
+	DiMustWriteLock(dentry);
+
+	parent = dget_parent(dentry);
+	di_write_lock_parent(parent);
+	sb = dentry->d_sb;
+	err = AuWbrCopyup(au_sbi(sb), dentry);
+	bcpup = err;
+	if (err < 0) {
+		err = 0; /* stop copyup, it is not an error */
+		goto out;
+	}
+	err = 0;
+
+	h_parent = au_h_dptr(parent, bcpup);
+	if (!h_parent) {
+		err = au_cpup_dirs(dentry, bcpup, NULL);
+		if (unlikely(err))
+			goto out;
+		h_parent = au_h_dptr(parent, bcpup);
+	}
+
+	h_dir = h_parent->d_inode;
+	h_dentry = au_h_dptr(dentry, bstart);
+	h_inode = h_dentry->d_inode;
+	dir = parent->d_inode;
+	//todo: meaningless lock if CONFIG_AUFS_DEBUG is disabled.
+	gparent = NULL;
+	if (unlikely(au_opt_test(au_mntflags(sb), UDBA_INOTIFY)
+		     && !IS_ROOT(parent))) {
+		gparent = dget_parent(parent);
+		ii_read_lock_parent2(gparent->d_inode);
+	}
+	au_hdir_lock(h_dir, dir, bcpup);
+	//todo: test parent-gparent relationship
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	AuDebugOn(au_h_dptr(dentry, bcpup));
+	err = au_sio_cpup_simple(dentry, bcpup, -1, AuCpup_DTIME);
+	AuTraceErr(err);
+	mutex_unlock(&h_inode->i_mutex);
+	au_hdir_unlock(h_dir, dir, bcpup);
+	if (unlikely(gparent)) {
+		ii_read_unlock(gparent->d_inode);
+		dput(gparent);
+	}
+
+ out:
+	di_write_unlock(parent);
+	dput(parent);
+	AuTraceErr(err);
+	return err;
+}
+
+int au_do_open(struct inode *inode, struct file *file,
+	       int (*open)(struct file *file, int flags))
+{
+	int err, coo;
+	struct dentry *dentry;
+	struct super_block *sb;
+	aufs_bindex_t bstart;
+	//struct inode *h_dir, *dir;
+
+	dentry = file->f_dentry;
+	LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(dentry));
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	coo = 0;
+	switch (au_mntflags(sb) & AuOptMask_COO) {
+	case AuOpt_COO_LEAF:
+		coo = !S_ISDIR(inode->i_mode);
+		break;
+	case AuOpt_COO_ALL:
+		coo = 1;
+		break;
+	}
+	err = au_finfo_init(file);
+	//if (LktrCond) {fi_write_unlock(file); fin_finfo(file); err = -1;}
+	if (unlikely(err))
+		goto out;
+
+	if (!coo) {
+		di_read_lock_child(dentry, AuLock_IR);
+		bstart = au_dbstart(dentry);
+	} else {
+		di_write_lock_child(dentry);
+		bstart = au_dbstart(dentry);
+		if (au_test_ro(sb, bstart, dentry->d_inode)) {
+			err = do_coo(dentry, bstart);
+			if (err) {
+				di_write_unlock(dentry);
+				goto out_finfo;
+			}
+			bstart = au_dbstart(dentry);
+		}
+		di_downgrade_lock(dentry, AuLock_IR);
+	}
+
+	err = open(file, file->f_flags);
+	//if (LktrCond) err = -1;
+	di_read_unlock(dentry, AuLock_IR);
+
+ out_finfo:
+	fi_write_unlock(file);
+	if (unlikely(err))
+		au_finfo_fin(file);
+	//DbgFile(file);
+ out:
+	si_read_unlock(sb);
+	AuTraceErr(err);
+	return err;
+}
+
+int au_reopen_nondir(struct file *file)
+{
+	int err;
+	struct dentry *dentry;
+	aufs_bindex_t bstart, bindex, bend;
+	struct file *h_file, *h_file_tmp;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+	bstart = au_dbstart(dentry);
+	AuDebugOn(S_ISDIR(dentry->d_inode->i_mode)
+		  || !au_h_dptr(dentry, bstart)->d_inode);
+
+	h_file_tmp = NULL;
+	if (au_fbstart(file) == bstart) {
+		h_file = au_h_fptr(file, bstart);
+		if (file->f_mode == h_file->f_mode)
+			return 0; /* success */
+		h_file_tmp = h_file;
+		get_file(h_file_tmp);
+		au_set_h_fptr(file, bstart, NULL);
+	}
+	AuDebugOn(au_fbstart(file) < bstart
+		  || au_fi(file)->fi_hfile[0 + bstart].hf_file);
+
+	h_file = au_h_open(dentry, bstart, file->f_flags & ~O_TRUNC, file);
+	//if (LktrCond) {fput(h_file); au_br_put(au_sbr(dentry->d_sb, bstart));
+	//h_file = ERR_PTR(-1);}
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out; // close all?
+	err = 0;
+	//cpup_file_flags(h_file, file);
+	au_set_fbstart(file, bstart);
+	au_set_h_fptr(file, bstart, h_file);
+	au_update_figen(file);
+	//file->f_ra = h_file->f_ra; //??
+
+	/* close lower files */
+	bend = au_fbend(file);
+	for (bindex = bstart + 1; bindex <= bend; bindex++)
+		au_set_h_fptr(file, bindex, NULL);
+	au_set_fbend(file, bstart);
+
+ out:
+	if (h_file_tmp)
+		fput(h_file_tmp);
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#if 0
+static int au_ready_to_write_wh(struct file *file, loff_t len,
+				aufs_bindex_t bcpup)
+{
+	int err;
+	struct dentry *dentry, *hi_wh, *old_h_dentry;
+	struct au_dinfo *dinfo;
+	aufs_bindex_t old_bstart;
+
+	AuTraceEnter();
+
+	dentry = file->f_dentry;
+	hi_wh = au_hi_wh(dentry->d_inode, bcpup);
+	if (!hi_wh)
+		err = au_sio_cpup_wh(dentry, bcpup, len, file);
+	else {
+		/* already copied-up after unlink */
+		dinfo = au_di(dentry);
+		old_bstart = dinfo->di_bstart;
+		dinfo->di_bstart = bcpup;
+		old_h_dentry = dinfo->di_hdentry[0 + bcpup].hd_dentry;
+		dinfo->di_hdentry[0 + bcpup].hd_dentry = hi_wh;
+		err = au_reopen_nondir(file);
+		dinfo->di_hdentry[0 + bcpup].hd_dentry = old_h_dentry;
+		dinfo->di_bstart = old_bstart;
+	}
+	//if (LktrCond) err = -1;
+
+	AuTraceErr(err);
+	return err;
+}
+#endif
+
+/*
+ * prepare the @file for writing.
+ */
+int au_ready_to_write(struct file *file, loff_t len)
+{
+	int err;
+	struct dentry *dentry, *parent, *h_dentry, *h_parent, *hi_wh,
+		*old_h_dentry, *gparent;
+	struct inode *h_inode, *h_dir, *inode, *dir;
+	struct super_block *sb;
+	aufs_bindex_t bstart, bcpup, old_bstart;
+	struct au_dinfo *dinfo;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, len %Ld\n", AuDLNPair(dentry), len);
+	FiMustWriteLock(file);
+
+	sb = dentry->d_sb;
+	bstart = au_fbstart(file);
+	AuDebugOn(au_fbr(file, bstart) != au_sbr(sb, bstart));
+
+	inode = dentry->d_inode;
+	AuDebugOn(S_ISDIR(inode->i_mode));
+	ii_read_lock_child(inode);
+	LKTRTrace("rdonly %d, bstart %d\n",
+		  au_test_ro(sb, bstart, inode), bstart);
+	err = au_test_ro(sb, bstart, inode);
+	ii_read_unlock(inode);
+	if (!err && (au_h_fptr(file, bstart)->f_mode & FMODE_WRITE))
+		return 0;
+
+	/* need to cpup */
+	di_write_lock_child(dentry);
+	parent = dget_parent(dentry);
+	di_write_lock_parent(parent);
+	err = AuWbrCopyup(au_sbi(sb), dentry);
+	bcpup = err;
+	if (unlikely(err < 0))
+		goto out_unlock;
+	err = 0;
+
+	h_parent = au_h_dptr(parent, bcpup);
+	if (!h_parent) {
+		err = au_cpup_dirs(dentry, bcpup, NULL);
+		//if (LktrCond) err = -1;
+		if (unlikely(err))
+			goto out_unlock;
+		h_parent = au_h_dptr(parent, bcpup);
+	}
+
+	//todo: meaningless lock if CONFIG_AUFS_DEBUG is disabled.
+	gparent = NULL;
+	if (unlikely(au_opt_test(au_mntflags(sb), UDBA_INOTIFY)
+		     && !IS_ROOT(parent))) {
+		gparent = dget_parent(parent);
+		ii_read_lock_parent2(gparent->d_inode);
+	}
+	h_dir = h_parent->d_inode;
+	h_dentry = au_h_fptr(file, au_fbstart(file))->f_dentry;
+	h_inode = h_dentry->d_inode;
+	dir = parent->d_inode;
+	au_hdir_lock(h_dir, dir, bcpup);
+	//todo: test parent-gparent relationship
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	if (d_unhashed(dentry) /* || d_unhashed(h_dentry) */
+	    /* || !h_inode->i_nlink */) {
+#if 0
+		err = au_ready_to_write_wh(file, len, bcpup);
+#else
+		hi_wh = au_hi_wh(inode, bcpup);
+		if (!hi_wh)
+			err = au_sio_cpup_wh(dentry, bcpup, len, file);
+		else {
+			/* already copied-up after unlink */
+			dinfo = au_di(dentry);
+			old_bstart = dinfo->di_bstart;
+			dinfo->di_bstart = bcpup;
+			old_h_dentry = dinfo->di_hdentry[0 + bcpup].hd_dentry;
+			dinfo->di_hdentry[0 + bcpup].hd_dentry = hi_wh;
+			err = au_reopen_nondir(file);
+			dinfo->di_hdentry[0 + bcpup].hd_dentry = old_h_dentry;
+			dinfo->di_bstart = old_bstart;
+		}
+		//if (LktrCond) err = -1;
+		AuTraceErr(err);
+#endif
+	} else {
+		if (!au_h_dptr(dentry, bcpup))
+			err = au_sio_cpup_simple(dentry, bcpup, len,
+						 AuCpup_DTIME);
+		//if (LktrCond) err = -1;
+		AuTraceErr(err);
+		if (!err)
+			err = au_reopen_nondir(file);
+		//if (LktrCond) err = -1;
+		AuTraceErr(err);
+	}
+	mutex_unlock(&h_inode->i_mutex);
+	au_hdir_unlock(h_dir, dir, bcpup);
+	if (unlikely(gparent)) {
+		ii_read_unlock(gparent->d_inode);
+		dput(gparent);
+	}
+
+ out_unlock:
+	di_write_unlock(parent);
+	di_write_unlock(dentry);
+	dput(parent);
+	AuTraceErr(err);
+	return err;
+
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int refresh_file_by_inode(struct file *file, int *need_reopen)
+{
+	int err;
+	struct au_finfo *finfo;
+	struct dentry *dentry, *parent, *old_h_dentry, *hi_wh;
+	struct inode *inode, *dir, *h_dir;
+	aufs_bindex_t bstart, new_bstart, old_bstart;
+	struct super_block *sb;
+	struct au_dinfo *dinfo;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+	FiMustWriteLock(file);
+
+	err = 0;
+	finfo = au_fi(file);
+	inode = dentry->d_inode;
+	sb = dentry->d_sb;
+ again:
+	bstart = au_ibstart(inode);
+	if (bstart == finfo->fi_bstart)
+		goto out;
+
+	new_bstart = bstart;
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	if (au_test_ro(sb, bstart, inode)) {
+		di_read_lock_parent(parent, !AuLock_IR);
+		err = AuWbrCopyup(au_sbi(sb), dentry);
+		new_bstart = err;
+		di_read_unlock(parent, !AuLock_IR);
+		//todo: err = -1;
+		if (unlikely(err < 0))
+			goto out_put;
+	}
+	di_read_unlock(dentry, AuLock_IR);
+	di_write_lock_child(dentry);
+	/* someone else might change our inode while we were sleeping */
+	if (bstart != au_ibstart(inode)) { // todo
+		di_downgrade_lock(dentry, AuLock_IR);
+		err = 0;
+		dput(parent);
+		goto again;
+	}
+	di_read_lock_parent(parent, AuLock_IR);
+	bstart = new_bstart;
+
+	hi_wh = au_hi_wh(inode, bstart);
+	if (au_opt_test(au_mntflags(sb), PLINK)
+	    && au_plink_test(sb, inode)
+	    && !d_unhashed(dentry)) {
+		err = au_test_and_cpup_dirs(dentry, bstart, NULL);
+
+		/* always superio. */
+#if 1
+		h_dir = au_h_dptr(parent, bstart)->d_inode;
+		au_hdir_lock(h_dir, dir, bstart);
+		err = au_sio_cpup_simple(dentry, bstart, -1, AuCpup_DTIME);
+		au_hdir_unlock(h_dir, dir, bstart);
+#else
+		if (!au_test_wkq(current)) {
+			int wkq_err;
+			struct cpup_pseudo_link_args args = {
+				.errp		= &err,
+				.dentry		= dentry,
+				.bdst		= bstart,
+				.do_lock	= 1
+			};
+			wkq_err = au_wkq_wait(call_cpup_pseudo_link, &args);
+			if (unlikely(wkq_err))
+				err = wkq_err;
+		} else
+			err = cpup_pseudo_link(dentry, bstart, /*do_lock*/1);
+#endif
+	} else if (hi_wh) {
+		/* already copied-up after unlink */
+		dinfo = au_di(dentry);
+		old_bstart = dinfo->di_bstart;
+		dinfo->di_bstart = bstart;
+		old_h_dentry = dinfo->di_hdentry[0 + bstart].hd_dentry;
+		dinfo->di_hdentry[0 + bstart].hd_dentry = hi_wh;
+		err = au_reopen_nondir(file);
+		dinfo->di_hdentry[0 + bstart].hd_dentry = old_h_dentry;
+		dinfo->di_bstart = old_bstart;
+		*need_reopen = 0;
+	}
+	di_read_unlock(parent, AuLock_IR);
+	di_downgrade_lock(dentry, AuLock_IR);
+
+ out_put:
+	dput(parent);
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+/*
+ * after branch manipulating, refresh the file.
+ */
+static int refresh_file(struct file *file, int (*reopen)(struct file *file))
+{
+	int err, new_sz, need_reopen;
+	struct dentry *dentry;
+	aufs_bindex_t bend, bindex, bstart, brid;
+	struct au_hfile *p;
+	struct au_finfo *finfo;
+	struct super_block *sb;
+	struct inode *inode;
+	struct file *hidden_file;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+	FiMustWriteLock(file);
+	DiMustReadLock(dentry);
+	inode = dentry->d_inode;
+	IiMustReadLock(inode);
+
+	err = -ENOMEM;
+	sb = dentry->d_sb;
+	finfo = au_fi(file);
+	bstart = finfo->fi_bstart;
+	bend = finfo->fi_bstart;
+	new_sz = sizeof(*finfo->fi_hfile) * (au_sbend(sb) + 1);
+	p = au_kzrealloc(finfo->fi_hfile, sizeof(*p) * (finfo->fi_bend + 1),
+			 new_sz, GFP_KERNEL);
+	//p = NULL;
+	if (unlikely(!p))
+		goto out;
+	finfo->fi_hfile = p;
+	hidden_file = p[0 + bstart].hf_file;
+
+	p = finfo->fi_hfile + finfo->fi_bstart;
+	brid = p->hf_br->br_id;
+	bend = finfo->fi_bend;
+	for (bindex = finfo->fi_bstart; bindex <= bend; bindex++, p++) {
+		struct au_hfile tmp, *q;
+		aufs_bindex_t new_bindex;
+
+		if (!p->hf_file)
+			continue;
+		new_bindex = au_find_bindex(sb, p->hf_br);
+		if (new_bindex == bindex)
+			continue;
+		if (new_bindex < 0) { // test here
+			au_set_h_fptr(file, bindex, NULL);
+			continue;
+		}
+
+		/* swap two hidden inode, and loop again */
+		q = finfo->fi_hfile + new_bindex;
+		tmp = *q;
+		*q = *p;
+		*p = tmp;
+		if (tmp.hf_file) {
+			bindex--;
+			p--;
+		}
+	}
+	{
+		aufs_bindex_t s = finfo->fi_bstart, e = finfo->fi_bend;
+		finfo->fi_bstart = 0;
+		finfo->fi_bend = au_sbend(sb);
+		finfo->fi_bstart = s;
+		finfo->fi_bend = e;
+	}
+
+	p = finfo->fi_hfile;
+	if (!au_test_mmapped(file) && !d_unhashed(dentry)) {
+		bend = au_sbend(sb);
+		for (finfo->fi_bstart = 0; finfo->fi_bstart <= bend;
+		     finfo->fi_bstart++, p++)
+			if (p->hf_file) {
+				if (p->hf_file->f_dentry
+				    && p->hf_file->f_dentry->d_inode)
+					break;
+				else
+					au_hfput(p);
+			}
+	} else {
+		bend = au_br_index(sb, brid);
+		//LKTRTrace("%d\n", bend);
+		for (finfo->fi_bstart = 0; finfo->fi_bstart < bend;
+		     finfo->fi_bstart++, p++)
+			if (p->hf_file)
+				au_hfput(p);
+		//LKTRTrace("%d\n", finfo->fi_bstart);
+		bend = au_sbend(sb);
+	}
+
+	p = finfo->fi_hfile + bend;
+	for (finfo->fi_bend = bend; finfo->fi_bend >= finfo->fi_bstart;
+	     finfo->fi_bend--, p--)
+		if (p->hf_file) {
+			if (p->hf_file->f_dentry
+			    && p->hf_file->f_dentry->d_inode)
+				break;
+			else
+				au_hfput(p);
+		}
+	AuDebugOn(finfo->fi_bend < finfo->fi_bstart);
+	//DbgFile(file);
+	//DbgDentry(file->f_dentry);
+
+	err = 0;
+	need_reopen = 1;
+	if (!au_test_mmapped(file))
+		err = refresh_file_by_inode(file, &need_reopen);
+	if (!err && need_reopen && !d_unhashed(dentry))
+		err = reopen(file);
+		//err = -1;
+	if (!err) {
+		au_update_figen(file);
+		//DbgFile(file);
+		return 0; /* success */
+	}
+
+	/* error, close all hidden files */
+	bend = au_fbend(file);
+	for (bindex = au_fbstart(file); bindex <= bend; bindex++)
+		au_set_h_fptr(file, bindex, NULL);
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+/* common function to regular file and dir */
+int au_reval_and_lock_finfo(struct file *file, int (*reopen)(struct file *file),
+			    int wlock, int locked)
+{
+	int err, pseudo_link;
+	struct dentry *dentry;
+	struct super_block *sb;
+	aufs_bindex_t bstart;
+	au_gen_t sgen, fgen;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, w %d, l %d\n", AuDLNPair(dentry), wlock, locked);
+	sb = dentry->d_sb;
+	SiMustAnyLock(sb);
+
+	err = 0;
+	sgen = au_sigen(sb);
+	fi_write_lock(file);
+	fgen = au_figen(file);
+	di_read_lock_child(dentry, AuLock_IR);
+	bstart = au_dbstart(dentry);
+	pseudo_link = (bstart != au_ibstart(dentry->d_inode));
+	di_read_unlock(dentry, AuLock_IR);
+	if (sgen == fgen && !pseudo_link && au_fbstart(file) == bstart) {
+		if (!wlock)
+			fi_downgrade_lock(file);
+		return 0; /* success */
+	}
+
+	LKTRTrace("sgen %d, fgen %d\n", sgen, fgen);
+	if (unlikely(sgen != au_digen(dentry)
+		     || sgen != au_iigen(dentry->d_inode))) {
+		/*
+		 * d_path() and path_lookup() is a simple and good approach
+		 * to revalidate. but si_rwsem in DEBUG_RWSEM will cause a
+		 * deadlock. removed the code.
+		 */
+		di_write_lock_child(dentry);
+		err = au_reval_dpath(dentry, sgen);
+		//if (LktrCond) err = -1;
+		di_write_unlock(dentry);
+		if (unlikely(err < 0))
+			goto out;
+		AuDebugOn(au_digen(dentry) != sgen
+			  || au_iigen(dentry->d_inode) != sgen);
+	}
+
+	di_read_lock_child(dentry, AuLock_IR);
+	err = refresh_file(file, reopen
+			   /* , au_opt_test(au_mnt_flags(sb), REFROF) */);
+	//if (LktrCond) err = -1;
+	di_read_unlock(dentry, AuLock_IR);
+	if (!err) {
+		if (!wlock)
+			fi_downgrade_lock(file);
+	} else
+		fi_write_unlock(file);
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* cf. aufs_nopage() */
+/* for madvise(2) */
+static int aufs_readpage(struct file *file, struct page *page)
+{
+	AuTraceEnter();
+	unlock_page(page);
+	return 0;
+}
+
+/* they will never be called. */
+#ifdef CONFIG_AUFS_DEBUG
+static int aufs_prepare_write(struct file *file, struct page *page,
+			      unsigned from, unsigned to)
+{ AuUnsupport(); return 0; }
+static int aufs_commit_write(struct file *file, struct page *page,
+			     unsigned from, unsigned to)
+{ AuUnsupport(); return 0; }
+static int aufs_write_begin(struct file *file, struct address_space *mapping,
+			    loff_t pos, unsigned len, unsigned flags,
+			    struct page **pagep, void **fsdata)
+{ AuUnsupport(); return 0; }
+static int aufs_write_end(struct file *file, struct address_space *mapping,
+			  loff_t pos, unsigned len, unsigned copied,
+			  struct page *page, void *fsdata)
+{ AuUnsupport(); return 0; }
+static int aufs_writepage(struct page *page, struct writeback_control *wbc)
+{ AuUnsupport(); return 0; }
+static void aufs_sync_page(struct page *page)
+{ AuUnsupport(); }
+
+#if 0 // comment
+static int aufs_writepages(struct address_space *mapping,
+			   struct writeback_control *wbc)
+{ AuUnsupport(); return 0; }
+static int aufs_readpages(struct file *filp, struct address_space *mapping,
+			  struct list_head *pages, unsigned nr_pages)
+{ AuUnsupport(); return 0; }
+static sector_t aufs_bmap(struct address_space *mapping, sector_t block)
+{ AuUnsupport(); return 0; }
+#endif
+
+static int aufs_set_page_dirty(struct page *page)
+{ AuUnsupport(); return 0; }
+static void aufs_invalidatepage(struct page *page, unsigned long offset)
+{ AuUnsupport(); }
+static int aufs_releasepage(struct page *page, gfp_t gfp)
+{ AuUnsupport(); return 0; }
+static ssize_t aufs_direct_IO(int rw, struct kiocb *iocb,
+			      const struct iovec *iov, loff_t offset,
+			      unsigned long nr_segs)
+{ AuUnsupport(); return 0; }
+//static int aufs_migratepage (struct page *newpage, struct page *page)
+//{ AuUnsupport(); return 0; }
+#if 0 //LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20)
+int (*launder_page) (struct page *);
+#endif
+#endif /* CONFIG_AUFS_DEBUG */
+
+struct address_space_operations aufs_aop = {
+	.readpage	= aufs_readpage,
+#ifdef CONFIG_AUFS_DEBUG
+	.writepage	= aufs_writepage,
+	.sync_page	= aufs_sync_page,
+	//.writepages	= aufs_writepages,
+	.set_page_dirty	= aufs_set_page_dirty,
+	//.readpages	= aufs_readpages,
+	.prepare_write	= aufs_prepare_write,
+	.commit_write	= aufs_commit_write,
+	.write_begin	= aufs_write_begin,
+	.write_end	= aufs_write_end,
+	//.bmap		= aufs_bmap,
+	.invalidatepage	= aufs_invalidatepage,
+	.releasepage	= aufs_releasepage,
+	.direct_IO	= aufs_direct_IO,
+	//.migratepage	= aufs_migratepage
+#endif /* CONFIG_AUFS_DEBUG */
+};
-- 
1.4.4.4