[PATCH 35/67] aufs lookup and dentry operations, source

[hooanon05]

From: Junjiro Okajima <hooanon05@xxxxxxxxxxx>

	initial commit
	aufs lookup and dentry operations, source

Signed-off-by: Junjiro Okajima <hooanon05@xxxxxxxxxxx>
---
 fs/aufs/dentry.c | 1020 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 1020 insertions(+), 0 deletions(-)

diff --git a/fs/aufs/dentry.c b/fs/aufs/dentry.c
new file mode 100644
index 0000000..06afa17
--- /dev/null
+++ b/fs/aufs/dentry.c
@@ -0,0 +1,1020 @@
+/*
+ * 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
+ */
+
+/*
+ * lookup and dentry operations
+ *
+ * $Id: dentry.c,v 1.5 2008/05/12 00:29:11 sfjro Exp $
+ */
+
+//#include <linux/fs.h>
+//#include <linux/namei.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * au_lkup_one() is a generic abstract entry function which calls
+ * lookup_one_len() or __lookup_hash() finally. it is some condisions that makes
+ * lookup complicated, which are nfs branch, open-intent and dlgt mode.
+ */
+
+#if defined(CONFIG_AUFS_BR_NFS) || defined(CONFIG_AUFS_DLGT)
+/* cf. lookup_one_len() in linux/fs/namei.c */
+struct dentry *au_lkup_one(const char *name, struct dentry *parent, int len,
+			   struct au_ndx *ndx)
+{
+	struct dentry *dentry;
+
+	LKTRTrace("%.*s/%.*s, ndx{%d, 0x%x}\n",
+		  AuDLNPair(parent), len, name, !!ndx->nfsmnt, ndx->flags);
+
+	ndx->nd_file = NULL;
+	if (!ndx->nfsmnt)
+		dentry = au_lkup_one_dlgt(name, parent, len, ndx->flags);
+	else
+		dentry = au_lkup_hash(name, parent, len, ndx);
+
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+#endif /* CONFIG_AUFS_BR_NFS || CONFIG_AUFS_DLGT */
+
+struct au_lkup_one_args {
+	struct dentry **errp;
+	const char *name;
+	struct dentry *parent;
+	int len;
+	struct au_ndx *ndx;
+};
+
+static void au_call_lkup_one(void *args)
+{
+	struct au_lkup_one_args *a = args;
+	*a->errp = au_lkup_one(a->name, a->parent, a->len, a->ndx);
+}
+
+#define AuLkup_ALLOW_NEG	1
+#define AuLkup_DLGT		(1 << 1)
+#define AuLkup_DIRPERM1		(1 << 2)
+#define au_ftest_lkup(flags, name)	((flags) & AuLkup_##name)
+#define au_fset_lkup(flags, name)	{ (flags) |= AuLkup_##name; }
+#define au_fclr_lkup(flags, name)	{ (flags) &= ~AuLkup_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuLkup_DLGT
+#define AuLkup_DLGT	0
+#undef AuLkup_DIRPERM1
+#define AuLkup_DIRPERM1	0
+#endif
+
+struct au_do_lookup_args {
+	unsigned int		flags;
+	mode_t			type;
+	struct nameidata	*nd;
+};
+
+/*
+ * returns positive/negative dentry, NULL or an error.
+ * NULL means whiteout-ed or not-found.
+ */
+static noinline_for_stack
+struct dentry *au_do_lookup(struct dentry *h_parent, struct dentry *dentry,
+			    aufs_bindex_t bindex, struct qstr *wh_name,
+			    struct au_do_lookup_args *args)
+{
+	struct dentry *h_dentry;
+	int wh_found, wh_able, opq, err;
+	struct inode *h_dir, *h_inode, *inode;
+	struct qstr *name;
+	struct super_block *sb;
+	unsigned int nd_flags;
+	struct au_ndx ndx = {
+		.flags	= 0,
+		.nd	= args->nd
+	};
+	const int allow_neg = au_ftest_lkup(args->flags, ALLOW_NEG);
+
+	LKTRTrace("%.*s/%.*s, b%d, {flags 0x%x, type 0%o, nd %d}\n",
+		  AuDLNPair(h_parent), AuDLNPair(dentry), bindex,
+		  args->flags, args->type, !!args->nd);
+	if (args->nd)
+		LKTRTrace("nd{0x%x}\n", args->nd->flags);
+	AuDebugOn(IS_ROOT(dentry));
+	h_dir = h_parent->d_inode;
+
+	nd_flags = 0;
+	wh_found = 0;
+	sb = dentry->d_sb;
+	ndx.nfsmnt = au_nfsmnt(sb, bindex);
+	if (unlikely(au_ftest_lkup(args->flags, DLGT)))
+		au_fset_ndx(ndx.flags, DLGT);
+	if (unlikely(au_ftest_lkup(args->flags, DIRPERM1)))
+		au_fset_ndx(ndx.flags, DIRPERM1);
+	LKTRTrace("nfsmnt %p\n", ndx.nfsmnt);
+	ndx.br = au_sbr(sb, bindex);
+	wh_able = au_br_whable(ndx.br->br_perm);
+	name = &dentry->d_name;
+	if (unlikely(wh_able))
+		wh_found = au_test_robr_wh(name, h_parent, wh_name,
+					   /*try_sio*/0, &ndx);
+	//if (LktrCond) wh_found = -1;
+	h_dentry = ERR_PTR(wh_found);
+	if (!wh_found)
+		goto real_lookup;
+	if (unlikely(wh_found < 0))
+		goto out;
+
+	/* We found a whiteout */
+	//au_set_dbend(dentry, bindex);
+	au_set_dbwh(dentry, bindex);
+	if (!allow_neg)
+		return NULL; /* success */
+	if (unlikely(ndx.nd
+		     && au_test_nfs(h_parent->d_sb)
+		     && (ndx.nd->flags & LOOKUP_CREATE))) {
+		nd_flags = ndx.nd->flags;
+		ndx.nd->flags &= ~(LOOKUP_OPEN | LOOKUP_CREATE);
+	}
+
+ real_lookup:
+	/* do not superio. */
+	h_dentry = au_lkup_one(name->name, h_parent, name->len, &ndx);
+	//if (LktrCond) {dput(h_dentry); h_dentry = ERR_PTR(-1);}
+	if (IS_ERR(h_dentry))
+		goto out;
+	AuDebugOn(d_unhashed(h_dentry));
+	h_inode = h_dentry->d_inode;
+	if (!h_inode) {
+		if (!allow_neg)
+			goto out_neg;
+	} else if (wh_found
+		   || (args->type && args->type != (h_inode->i_mode & S_IFMT)))
+		goto out_neg;
+
+	if (au_dbend(dentry) <= bindex)
+		au_set_dbend(dentry, bindex);
+	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
+		au_set_dbstart(dentry, bindex);
+	au_set_h_dptr(dentry, bindex, h_dentry);
+
+	err = au_br_nfs_h_intent(ndx.nd_file, dentry, bindex, args->nd);
+	if (unlikely(err)) {
+		h_dentry = ERR_PTR(err);
+		goto out;
+	}
+
+	inode = dentry->d_inode;
+	if (!h_inode || !S_ISDIR(h_inode->i_mode) || !wh_able
+	    || (inode && !S_ISDIR(inode->i_mode)))
+		goto out; /* success */
+
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	opq = au_diropq_test(h_dentry, &ndx);
+	//if (LktrCond) opq = -1;
+	mutex_unlock(&h_inode->i_mutex);
+	if (opq > 0)
+		au_set_dbdiropq(dentry, bindex);
+	else if (unlikely(opq < 0)) {
+		au_set_h_dptr(dentry, bindex, NULL);
+		h_dentry = ERR_PTR(opq);
+	}
+	goto out;
+
+ out_neg:
+	dput(h_dentry);
+	h_dentry = NULL;
+ out:
+	if (unlikely(nd_flags))
+		ndx.nd->flags |= (nd_flags & (LOOKUP_OPEN | LOOKUP_CREATE));
+	AuTraceErrPtr(h_dentry);
+	return h_dentry;
+}
+
+/*
+ * returns the number of hidden positive dentries,
+ * otherwise an error.
+ * can be called at unlinking with @type is zero.
+ */
+int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
+		   struct nameidata *nd)
+{
+	int npositive, err, isdir;
+	struct dentry *parent;
+	aufs_bindex_t bindex, btail, bdiropq;
+	const struct qstr *name = &dentry->d_name;
+	struct qstr whname;
+	struct super_block *sb;
+	unsigned int mnt_flags;
+	struct inode *inode;
+	struct au_do_lookup_args args = {
+		.type	= type,
+		.nd	= nd
+	};
+
+	LKTRTrace("%.*s, b%d, type 0%o\n", AuLNPair(name), bstart, type);
+	AuDebugOn(bstart < 0 || IS_ROOT(dentry));
+
+	/* dir may not be locked */
+	parent = dget_parent(dentry);
+
+	err = au_test_robr_shwh(dentry->d_sb, name);
+	if (unlikely(err))
+		goto out;
+
+	err = au_wh_name_alloc(name->name, name->len, &whname);
+	//if (LktrCond) {au_wh_name_free(&whname); err = -1;}
+	if (unlikely(err))
+		goto out;
+
+	sb = dentry->d_sb;
+	mnt_flags = au_mntflags(sb);
+	inode = dentry->d_inode;
+	isdir = (inode && S_ISDIR(inode->i_mode));
+	args.flags = 0;
+	if (unlikely(au_opt_test_dlgt(mnt_flags)))
+		au_fset_lkup(args.flags, DLGT);
+	if (unlikely(au_opt_test_dirperm1(mnt_flags)))
+		au_fset_lkup(args.flags, DIRPERM1);
+	if (!type)
+		au_fset_lkup(args.flags, ALLOW_NEG);
+	npositive = 0;
+	btail = au_dbtaildir(parent);
+	for (bindex = bstart; bindex <= btail; bindex++) {
+		struct dentry *h_parent, *h_dentry;
+		struct inode *h_inode, *h_dir;
+
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (h_dentry) {
+			if (h_dentry->d_inode)
+				npositive++;
+			if (type != S_IFDIR)
+				break;
+			continue;
+		}
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent)
+			continue;
+		h_dir = h_parent->d_inode;
+		if (!h_dir || !S_ISDIR(h_dir->i_mode))
+			continue;
+
+		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+		h_dentry = au_do_lookup(h_parent, dentry, bindex, &whname,
+					&args);
+		// do not dput for testing
+		//if (LktrCond) {h_dentry = ERR_PTR(-1);}
+		mutex_unlock(&h_dir->i_mutex);
+		err = PTR_ERR(h_dentry);
+		if (IS_ERR(h_dentry))
+			goto out_wh;
+		au_fclr_lkup(args.flags, ALLOW_NEG);
+
+		if (au_dbwh(dentry) >= 0)
+			break;
+		if (!h_dentry)
+			continue;
+		h_inode = h_dentry->d_inode;
+		if (!h_inode)
+			continue;
+		npositive++;
+		if (!args.type)
+			args.type = h_inode->i_mode & S_IFMT;
+		if (args.type != S_IFDIR)
+			break;
+		else if (isdir) {
+			/* the type of lowers may be different */
+			bdiropq = au_dbdiropq(dentry);
+			if (bdiropq >= 0 && bdiropq <= bindex)
+				break;
+		}
+	}
+
+	if (npositive) {
+		LKTRLabel(positive);
+		au_update_dbstart(dentry);
+	}
+	err = npositive;
+
+ out_wh:
+	au_wh_name_free(&whname);
+ out:
+	dput(parent);
+	AuTraceErr(err);
+	return err;
+}
+
+struct dentry *au_sio_lkup_one(const char *name, struct dentry *parent, int len,
+			       struct au_ndx *ndx)
+{
+	struct dentry *dentry;
+	int wkq_err;
+
+	LKTRTrace("%.*s/%.*s\n", AuDLNPair(parent), len, name);
+
+	if (!au_test_h_perm_sio(parent->d_inode, MAY_EXEC,
+				au_ftest_ndx(ndx->flags, DLGT)))
+		dentry = au_lkup_one(name, parent, len, ndx);
+	else {
+		// ugly
+		unsigned int flags = ndx->flags;
+		struct au_lkup_one_args args = {
+			.errp	= &dentry,
+			.name	= name,
+			.parent	= parent,
+			.len	= len,
+			.ndx	= ndx
+		};
+
+		au_fclr_ndx(ndx->flags, DLGT);
+		au_fclr_ndx(ndx->flags, DIRPERM1);
+		wkq_err = au_wkq_wait(au_call_lkup_one, &args, /*dlgt*/0);
+		if (unlikely(wkq_err))
+			dentry = ERR_PTR(wkq_err);
+		ndx->flags = flags;
+	}
+
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+
+/*
+ * lookup @dentry on @bindex which should be negative.
+ */
+int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	int err;
+	struct dentry *parent, *h_parent, *h_dentry;
+	struct inode *h_dir;
+	struct au_ndx ndx = {
+		.flags	= 0,
+		.nd	= NULL,
+		//.br	= NULL
+	};
+	struct super_block *sb;
+	unsigned int mnt_flags;
+
+	LKTRTrace("%.*s, b%d\n", AuDLNPair(dentry), bindex);
+	/* dir may not be locked */
+	parent = dget_parent(dentry);
+	AuDebugOn(!parent || !parent->d_inode
+		  || !S_ISDIR(parent->d_inode->i_mode));
+	h_parent = au_h_dptr(parent, bindex);
+	AuDebugOn(!h_parent);
+	h_dir = h_parent->d_inode;
+	AuDebugOn(!h_dir || !S_ISDIR(h_dir->i_mode));
+
+	sb = dentry->d_sb;
+	mnt_flags = au_mntflags(sb);
+	ndx.nfsmnt = au_nfsmnt(sb, bindex);
+	if (unlikely(au_opt_test_dlgt(mnt_flags)))
+		au_fset_ndx(ndx.flags, DLGT);
+	if (unlikely(au_opt_test_dirperm1(mnt_flags)))
+		au_fset_ndx(ndx.flags, DIRPERM1);
+	h_dentry = au_sio_lkup_one(dentry->d_name.name, h_parent,
+				   dentry->d_name.len, &ndx);
+	//if (LktrCond) {dput(h_dentry); h_dentry = ERR_PTR(-1);}
+	err = PTR_ERR(h_dentry);
+	if (IS_ERR(h_dentry))
+		goto out;
+	if (unlikely(h_dentry->d_inode)) {
+		err = -EIO;
+		AuIOErr("b%d %.*s should be negative.\n",
+			bindex, AuDLNPair(h_dentry));
+		dput(h_dentry);
+		goto out;
+	}
+
+	if (bindex < au_dbstart(dentry))
+		au_set_dbstart(dentry, bindex);
+	if (au_dbend(dentry) < bindex)
+		au_set_dbend(dentry, bindex);
+	au_set_h_dptr(dentry, bindex, h_dentry);
+	err = 0;
+
+ out:
+	dput(parent);
+	AuTraceErr(err);
+	return err;
+}
+
+/*
+ * returns the number of found hidden positive dentries,
+ * otherwise an error.
+ */
+int au_refresh_hdentry(struct dentry *dentry, mode_t type)
+{
+	int npositive, new_sz;
+	struct au_dinfo *dinfo;
+	struct super_block *sb;
+	struct dentry *parent;
+	aufs_bindex_t bindex, parent_bend, parent_bstart, bwh, bdiropq, bend;
+	struct au_hdentry *p;
+	au_gen_t sgen;
+
+	LKTRTrace("%.*s, type 0%o\n", AuDLNPair(dentry), type);
+	DiMustWriteLock(dentry);
+	sb = dentry->d_sb;
+	AuDebugOn(IS_ROOT(dentry));
+	sgen = au_sigen(sb);
+	parent = dget_parent(dentry);
+	AuDebugOn(au_digen(parent) != sgen
+		  || au_iigen(parent->d_inode) != sgen);
+
+	npositive = -ENOMEM;
+	new_sz = sizeof(*dinfo->di_hdentry) * (au_sbend(sb) + 1);
+	dinfo = au_di(dentry);
+	p = au_kzrealloc(dinfo->di_hdentry, sizeof(*p) * (dinfo->di_bend + 1),
+			 new_sz, GFP_KERNEL);
+	//p = NULL;
+	if (unlikely(!p))
+		goto out;
+	dinfo->di_hdentry = p;
+
+	bend = dinfo->di_bend;
+	bwh = dinfo->di_bwh;
+	bdiropq = dinfo->di_bdiropq;
+	p += dinfo->di_bstart;
+	for (bindex = dinfo->di_bstart; bindex <= bend; bindex++, p++) {
+		struct dentry *hd, *hdp;
+		struct au_hdentry tmp, *q;
+		aufs_bindex_t new_bindex;
+
+		hd = p->hd_dentry;
+		if (!hd)
+			continue;
+		hdp = dget_parent(hd);
+		if (hdp == au_h_dptr(parent, bindex)) {
+			dput(hdp);
+			continue;
+		}
+
+		new_bindex = au_find_dbindex(parent, hdp);
+		dput(hdp);
+		AuDebugOn(new_bindex == bindex);
+		if (dinfo->di_bwh == bindex)
+			bwh = new_bindex;
+		if (dinfo->di_bdiropq == bindex)
+			bdiropq = new_bindex;
+		if (new_bindex < 0) { // test here
+			au_hdput(p, /*do_free*/0);
+			p->hd_dentry = NULL;
+			continue;
+		}
+		/* swap two hidden dentries, and loop again */
+		q = dinfo->di_hdentry + new_bindex;
+		tmp = *q;
+		*q = *p;
+		*p = tmp;
+		if (tmp.hd_dentry) {
+			bindex--;
+			p--;
+		}
+	}
+
+	// test here
+	dinfo->di_bwh = -1;
+	if (unlikely(bwh >= 0 && bwh <= au_sbend(sb) && au_sbr_whable(sb, bwh)))
+		dinfo->di_bwh = bwh;
+	dinfo->di_bdiropq = -1;
+	if (unlikely(bdiropq >= 0 && bdiropq <= au_sbend(sb)
+		     && au_sbr_whable(sb, bdiropq)))
+		dinfo->di_bdiropq = bdiropq;
+	parent_bend = au_dbend(parent);
+	p = dinfo->di_hdentry;
+	for (bindex = 0; bindex <= parent_bend; bindex++, p++)
+		if (p->hd_dentry) {
+			dinfo->di_bstart = bindex;
+			break;
+		}
+	p = dinfo->di_hdentry + parent_bend;
+	//for (bindex = parent_bend; bindex > dinfo->di_bstart; bindex--, p--)
+	for (bindex = parent_bend; bindex >= 0; bindex--, p--)
+		if (p->hd_dentry) {
+			dinfo->di_bend = bindex;
+			break;
+		}
+
+	npositive = 0;
+	parent_bstart = au_dbstart(parent);
+	if (type != S_IFDIR && dinfo->di_bstart == parent_bstart)
+		goto out_dgen; /* success */
+
+	npositive = au_lkup_dentry(dentry, parent_bstart, type, /*nd*/NULL);
+	//if (LktrCond) npositive = -1;
+	if (npositive < 0)
+		goto out;
+	if (unlikely(dinfo->di_bwh >= 0 && dinfo->di_bwh <= dinfo->di_bstart))
+		d_drop(dentry);
+
+ out_dgen:
+	au_update_digen(dentry);
+ out:
+	dput(parent);
+	AuTraceErr(npositive);
+	return npositive;
+}
+
+#ifdef CONFIG_AUFS_FAKE_DM
+
+static int au_lock_nd(struct dentry *dentry, struct nameidata *nd)
+{
+	return 0;
+}
+
+static void au_unlock_nd(int locked, struct nameidata *nd)
+{
+	/* empty */
+}
+
+#else
+
+static int au_lock_nd(struct dentry *dentry, struct nameidata *nd)
+{
+	int locked = 0;
+	if (nd && dentry != nd->path.dentry) {
+		di_read_lock_parent(nd->path.dentry, 0);
+		locked = 1;
+	}
+	return locked;
+}
+
+static void au_unlock_nd(int locked, struct nameidata *nd)
+{
+	if (locked)
+		di_read_unlock(nd->path.dentry, 0);
+}
+
+#endif /* CONFIG_AUFS_FAKE_DM */
+
+//#define TestingFuse
+static noinline_for_stack int
+au_do_h_d_reval(struct dentry *dentry, aufs_bindex_t bindex,
+		struct nameidata *nd, struct dentry *h_dentry)
+{
+	int err, valid, e;
+	int (*reval)(struct dentry *, struct nameidata *);
+	struct super_block *sb;
+	struct nameidata fake_nd, *p;
+
+	LKTRTrace("%.*s, b%d, nd %d\n", AuDLNPair(dentry), bindex, !!nd);
+
+	err = 0;
+	reval = NULL;
+	if (h_dentry->d_op)
+		reval = h_dentry->d_op->d_revalidate;
+	if (!reval)
+		goto out;
+
+	sb = dentry->d_sb;
+	if (nd) {
+		memcpy(&fake_nd, nd, sizeof(*nd));
+		err = au_fake_intent(&fake_nd, au_sbr_perm(sb, bindex));
+		if (unlikely(err)) {
+			err = -EINVAL;
+			goto out;
+		}
+	}
+	p = au_fake_dm(&fake_nd, nd, sb, bindex);
+	AuDebugOn(IS_ERR(p));
+	AuDebugOn(nd && p != &fake_nd);
+	LKTRTrace("b%d\n", bindex);
+
+	/* it may return tri-state */
+	valid = reval(h_dentry, p);
+	if (unlikely(valid < 0))
+		err = valid;
+	else if (!valid)
+		err = -EINVAL;
+	else
+		AuDebugOn(err);
+
+	if (p) {
+		AuDebugOn(!nd);
+		e = au_hin_after_reval(p, dentry, bindex, nd->intent.open.file);
+#ifndef TestingFuse
+		au_update_fuse_h_inode(p->path.mnt, h_dentry); /*ignore*/
+#endif
+		if (unlikely(e && !err))
+			err = e;
+	}
+#ifndef TestingFuse
+	else
+		au_update_fuse_h_inode(NULL, h_dentry); /*ignore*/
+#endif
+	au_fake_dm_release(p);
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+static noinline_for_stack int
+h_d_revalidate(struct dentry *dentry, struct inode *inode,
+	       struct nameidata *nd, int do_udba)
+{
+	int err, plus, locked, unhashed, is_root, h_plus;
+	aufs_bindex_t bindex, btail, bstart, ibs, ibe;
+	struct super_block *sb;
+	struct inode *first, *h_inode, *h_cached_inode;
+	umode_t mode, h_mode;
+	struct dentry *h_dentry;
+	struct qstr *name;
+
+	LKTRTrace("%.*s, nd %d\n", AuDLNPair(dentry), !!nd);
+	AuDebugOn(inode && au_digen(dentry) != au_iigen(inode));
+
+	err = 0;
+	sb = dentry->d_sb;
+	plus = 0;
+	mode = 0;
+	first = NULL;
+	ibs = -1;
+	ibe = -1;
+	unhashed = d_unhashed(dentry);
+	is_root = IS_ROOT(dentry);
+	name = &dentry->d_name;
+
+	/*
+	 * Theoretically, REVAL test should be unnecessary in case of INOTIFY.
+	 * But inotify doesn't fire some necessary events,
+	 *	IN_ATTRIB for atime/nlink/pageio
+	 *	IN_DELETE for NFS dentry
+	 * Let's do REVAL test too.
+	 */
+	if (do_udba && inode) {
+		mode = (inode->i_mode & S_IFMT);
+		plus = (inode->i_nlink > 0);
+		first = au_h_iptr(inode, au_ibstart(inode));
+		ibs = au_ibstart(inode);
+		ibe = au_ibend(inode);
+	}
+
+	bstart = au_dbstart(dentry);
+	btail = bstart;
+	if (inode && S_ISDIR(inode->i_mode))
+		btail = au_dbtaildir(dentry);
+	locked = au_lock_nd(dentry, nd);
+	for (bindex = bstart; bindex <= btail; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (!h_dentry)
+			continue;
+
+		LKTRTrace("b%d, %.*s\n", bindex, AuDLNPair(h_dentry));
+#ifdef TestingFuse
+		/* force re-lookup for fuse, in order to update attributes */
+		if (unlikely(au_test_fuse(h_dentry->d_sb)))
+			goto err;
+#endif
+
+		if (unlikely(do_udba
+			     && !is_root
+			     && (unhashed != d_unhashed(h_dentry)
+//#if 1
+				 || name->len != h_dentry->d_name.len
+				 || memcmp(name->name, h_dentry->d_name.name,
+					   name->len)
+//#endif
+				     ))) {
+			LKTRTrace("unhash 0x%x 0x%x, %.*s %.*s\n",
+				  unhashed, d_unhashed(h_dentry),
+				  AuDLNPair(dentry), AuDLNPair(h_dentry));
+			goto err;
+		}
+
+		err = au_do_h_d_reval(dentry, bindex, nd, h_dentry);
+		if (unlikely(err))
+			/* do not goto err, to keep the errno */
+			break;
+
+		if (unlikely(!do_udba))
+			continue;
+
+		/* UDBA tests */
+		h_inode = h_dentry->d_inode;
+		if (unlikely(!!inode != !!h_inode)) {
+			//AuDbg("here\n");
+			goto err;
+		}
+
+		h_plus = plus;
+		h_mode = mode;
+		h_cached_inode = h_inode;
+		if (h_inode) {
+			h_mode = (h_inode->i_mode & S_IFMT);
+			h_plus = (h_inode->i_nlink > 0);
+			//AuDbgInode(inode);
+			//AuDbgInode(h_inode);
+		}
+		if (inode && ibs <= bindex && bindex <= ibe)
+			h_cached_inode = au_h_iptr(inode, bindex);
+
+		LKTRTrace("{%d, 0%o, %d}, h{%d, 0%o, %d}\n",
+			  plus, mode, !!h_cached_inode,
+			  h_plus, h_mode, !!h_inode);
+		if (unlikely(plus != h_plus
+			     || mode != h_mode
+			     || h_cached_inode != h_inode))
+			goto err;
+		continue;
+
+	err:
+		err = -EINVAL;
+		break;
+	}
+	au_unlock_nd(locked, nd);
+
+	/*
+	 * judging by timestamps is meaningless since some filesystem uses
+	 * CURRENT_TIME_SEC instead of CURRENT_TIME.
+	 */
+	/*
+	 * NFS may stop IN_DELETE because of DCACHE_NFSFS_RENAMED.
+	 */
+
+#if 0 // debug
+	if (!err)
+		au_update_from_fuse(inode);
+	if (unlikely(!err && udba && first))
+		au_cpup_attr_all(inode);
+#endif
+
+	AuTraceErr(err);
+	return err;
+}
+
+static noinline_for_stack int
+simple_reval_dpath(struct dentry *dentry, au_gen_t sgen)
+{
+	int err;
+	mode_t type;
+	struct dentry *parent;
+	struct inode *inode;
+
+	LKTRTrace("%.*s, sgen %d\n", AuDLNPair(dentry), sgen);
+	SiMustAnyLock(dentry->d_sb);
+	DiMustWriteLock(dentry);
+	inode = dentry->d_inode;
+	AuDebugOn(!inode);
+
+	if (au_digen(dentry) == sgen && au_iigen(inode) == sgen)
+		return 0;
+
+	parent = dget_parent(dentry);
+	di_read_lock_parent(parent, AuLock_IR);
+	AuDebugOn(au_digen(parent) != sgen
+		  || au_iigen(parent->d_inode) != sgen);
+#ifdef CONFIG_AUFS_DEBUG
+	{
+		int i, j;
+		struct au_dcsub_pages dpages;
+		struct au_dpage *dpage;
+		struct dentry **dentries;
+
+		err = au_dpages_init(&dpages, GFP_TEMPORARY);
+		AuDebugOn(err);
+		err = au_dcsub_pages_rev(&dpages, parent, /*do_include*/1, NULL,
+					 NULL);
+		AuDebugOn(err);
+		for (i = dpages.ndpage - 1; !err && i >= 0; i--) {
+			dpage = dpages.dpages + i;
+			dentries = dpage->dentries;
+			for (j = dpage->ndentry - 1; !err && j >= 0; j--)
+				AuDebugOn(au_digen(dentries[j]) != sgen);
+		}
+		au_dpages_free(&dpages);
+	}
+#endif
+	type = (inode->i_mode & S_IFMT);
+	/* returns a number of positive dentries */
+	err = au_refresh_hdentry(dentry, type);
+	if (err >= 0)
+		err = au_refresh_hinode(inode, dentry);
+	di_read_unlock(parent, AuLock_IR);
+	dput(parent);
+	AuTraceErr(err);
+	return err;
+}
+
+int au_reval_dpath(struct dentry *dentry, au_gen_t sgen)
+{
+	int err;
+	struct dentry *d, *parent;
+	struct inode *inode;
+
+	LKTRTrace("%.*s, sgen %d\n", AuDLNPair(dentry), sgen);
+	AuDebugOn(!dentry->d_inode);
+	DiMustWriteLock(dentry);
+
+	if (!au_ftest_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS))
+		return simple_reval_dpath(dentry, sgen);
+
+	/* slow loop, keep it simple and stupid */
+	/* cf: au_cpup_dirs() */
+	err = 0;
+	parent = NULL;
+	while (au_digen(dentry) != sgen || au_iigen(dentry->d_inode) != sgen) {
+		d = dentry;
+		while (1) {
+			dput(parent);
+			parent = dget_parent(d);
+			if (au_digen(parent) == sgen
+			    && au_iigen(parent->d_inode) == sgen)
+				break;
+			d = parent;
+		}
+
+		inode = d->d_inode;
+		if (d != dentry) {
+			//mutex_lock(&inode->i_mutex);
+			di_write_lock_child(d);
+		}
+
+		/* someone might update our dentry while we were sleeping */
+		if (au_digen(d) != sgen || au_iigen(d->d_inode) != sgen) {
+			di_read_lock_parent(parent, AuLock_IR);
+			/* returns a number of positive dentries */
+			err = au_refresh_hdentry(d, inode->i_mode & S_IFMT);
+			//err = -1;
+			if (err >= 0)
+				err = au_refresh_hinode(inode, d);
+			//err = -1;
+			di_read_unlock(parent, AuLock_IR);
+		}
+
+		if (d != dentry) {
+			di_write_unlock(d);
+			//mutex_unlock(&inode->i_mutex);
+		}
+		dput(parent);
+		if (unlikely(err))
+			break;
+	}
+
+	AuTraceErr(err);
+	return err;
+}
+
+/*
+ * THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise.
+ * nfsd passes NULL as nameidata.
+ */
+static int aufs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+	int valid, err, do_udba;
+	struct super_block *sb;
+	au_gen_t sgen;
+	struct inode *inode;
+	struct nameidata tmp_nd, *ndp;
+
+	LKTRTrace("dentry %.*s\n", AuDLNPair(dentry));
+	if (nd && nd->path.dentry)
+		LKTRTrace("nd{%.*s, 0x%x}\n",
+			  AuDLNPair(nd->path.dentry), nd->flags);
+	//dir case: AuDebugOn(dentry->d_parent != nd->dentry);
+	//remove failure case:AuDebugOn(!IS_ROOT(dentry) && d_unhashed(dentry));
+	AuDebugOn(!dentry->d_fsdata);
+	//AuDbgDentry(dentry);
+
+	err = -EINVAL;
+	inode = dentry->d_inode;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+
+	sgen = au_sigen(sb);
+	if (au_digen(dentry) == sgen)
+		di_read_lock_child(dentry, !AuLock_IR);
+	else {
+		AuDebugOn(IS_ROOT(dentry));
+#ifdef ForceInotify
+		AuDbg("UDBA or digen, %.*s\n", AuDLNPair(dentry));
+#endif
+		di_write_lock_child(dentry);
+		if (inode)
+			err = au_reval_dpath(dentry, sgen);
+		//err = -1;
+		di_downgrade_lock(dentry, AuLock_IR);
+		if (unlikely(err))
+			goto out;
+		if (inode)
+			ii_read_unlock(inode);
+		AuDebugOn(au_digen(dentry) != sgen);
+	}
+
+	if (inode) {
+		if (au_iigen(inode) == sgen)
+			ii_read_lock_child(inode);
+		else {
+			AuDebugOn(IS_ROOT(dentry));
+#ifdef ForceInotify
+			AuDbg("UDBA or survived, %.*s\n", AuDLNPair(dentry));
+			//au_debug_on();
+			//AuDbgInode(inode);
+			//au_debug_off();
+#endif
+			ii_write_lock_child(inode);
+			err = au_refresh_hinode(inode, dentry);
+			ii_downgrade_lock(inode);
+			if (unlikely(err))
+				goto out;
+			AuDebugOn(au_iigen(inode) != sgen);
+		}
+	}
+
+#if 0 // fix it
+	/* parent dir i_nlink is not updated in the case of setattr */
+	if (S_ISDIR(inode->i_mode)) {
+		mutex_lock(&inode->i_mutex);
+		ii_write_lock(inode);
+		au_cpup_attr_nlink(inode);
+		ii_write_unlock(inode);
+		mutex_unlock(&inode->i_mutex);
+	}
+#endif
+
+	AuDebugOn(au_digen(dentry) != sgen);
+	AuDebugOn(inode && au_iigen(inode) != sgen);
+	err = -EINVAL;
+	do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
+	if (do_udba && inode) {
+		aufs_bindex_t bstart = au_ibstart(inode);
+		if (bstart >= 0
+		    && au_test_higen(inode, au_h_iptr(inode, bstart)))
+			goto out;
+	}
+	ndp = au_dup_nd(au_sbi(sb), &tmp_nd, nd);
+	err = h_d_revalidate(dentry, inode, ndp, do_udba);
+	//err = -1;
+
+ out:
+#if 0
+	AuDbgDentry(dentry);
+	if (nd && (nd->flags & LOOKUP_OPEN)) {
+		LKTRTrace("intent.open.file %p\n", nd->intent.open.file);
+		if (nd->intent.open.file && nd->intent.open.file->f_dentry)
+			AuDbgFile(nd->intent.open.file);
+	}
+#endif
+	au_store_fmode_exec(nd, inode);
+
+	if (inode)
+		ii_read_unlock(inode);
+	di_read_unlock(dentry, !AuLock_IR);
+	si_read_unlock(sb);
+	AuTraceErr(err);
+	valid = !err;
+	if (!valid)
+		LKTRTrace("%.*s invalid\n", AuDLNPair(dentry));
+	return valid;
+}
+
+static void aufs_d_release(struct dentry *dentry)
+{
+	struct au_dinfo *dinfo;
+	aufs_bindex_t bend, bindex;
+
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+	AuDebugOn(!d_unhashed(dentry));
+
+	dinfo = dentry->d_fsdata;
+	if (unlikely(!dinfo))
+		return;
+
+	/* dentry may not be revalidated */
+	bindex = dinfo->di_bstart;
+	if (bindex >= 0) {
+		struct au_hdentry *p;
+		bend = dinfo->di_bend;
+		AuDebugOn(bend < bindex);
+		p = dinfo->di_hdentry + bindex;
+		while (bindex++ <= bend) {
+			if (p->hd_dentry)
+				au_hdput(p, /*do_free*/1);
+			p++;
+		}
+	}
+	kfree(dinfo->di_hdentry);
+	au_cache_free_dinfo(dinfo);
+}
+
+struct dentry_operations aufs_dop = {
+	.d_revalidate	= aufs_d_revalidate,
+	.d_release	= aufs_d_release,
+	/* never use d_delete, especially in case of nfs server */
+	//.d_delete	= aufs_d_delete
+	//.d_iput		= aufs_d_iput
+};
-- 
1.4.4.4

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