[PATCH 16/67] aufs lookup functions for NFS branch in linux-2.6.19 and later

[hooanon05@yahoo.co.jp]

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

	initial commit
	aufs lookup functions for NFS branch in linux-2.6.19 and later

Signed-off-by: Junjiro Okajima <hooanon05@yahoo.co.jp>
---
 fs/aufs/br_nfs.c |  391 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 391 insertions(+), 0 deletions(-)

diff --git a/fs/aufs/br_nfs.c b/fs/aufs/br_nfs.c
new file mode 100644
index 0000000..ab5c8c2
--- /dev/null
+++ b/fs/aufs/br_nfs.c
@@ -0,0 +1,391 @@
+/*
+ * Copyright (C) 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 functions for NFS branch in linux-2.6.19 and later
+ *
+ * $Id: br_nfs.c,v 1.3 2008/05/04 23:51:14 sfjro Exp $
+ */
+
+#include "aufs.h"
+
+static struct file *au_find_h_intent(struct au_hdentry *hd, struct file *file)
+{
+	struct file *h_file, *hf;
+	struct au_hdintent *hdi, *tmp, *do_free;
+
+	LKTRTrace("%.*s\n", AuDLNPair(hd->hd_dentry));
+
+	h_file = NULL;
+	do_free = NULL;
+	spin_lock(&hd->hd_lock);
+	list_for_each_entry_safe(hdi, tmp, hd->hd_intent_list, hdi_list) {
+		hf = hdi->hdi_file[AuIntent_BRANCH];
+		if (hdi->hdi_file[AuIntent_AUFS] == file
+		    && hf->f_dentry == hd->hd_dentry) {
+			h_file = hf;
+			do_free = hdi;
+			list_del(&hdi->hdi_list);
+			break;
+		}
+	}
+	spin_unlock(&hd->hd_lock);
+	kfree(do_free);
+
+	return h_file;
+}
+
+struct file *au_h_intent(struct dentry *dentry, aufs_bindex_t bindex,
+			 struct file *file)
+{
+	struct file *h_file;
+	struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
+
+	LKTRTrace("%.*s, b%d, f %p\n", AuDLNPair(dentry), bindex, file);
+	DiMustAnyLock(dentry);
+	AuDebugOn(bindex < au_di(dentry)->di_bstart
+		  || bindex > au_di(dentry)->di_bend);
+
+	h_file = NULL;
+	if (!hd->hd_intent_list || !file)
+		return h_file; /* success */
+
+	//AuDebugOn(au_test_wkq(current));
+	h_file = au_find_h_intent(hd, file);
+	//AuDbgFile(h_file);
+	return h_file;
+}
+
+static int au_set_h_intent(struct dentry *dentry, aufs_bindex_t bindex,
+			   struct file *file, struct file *h_file)
+{
+	int err;
+	struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
+	struct au_hdintent *hdi;
+	struct file *hf;
+
+	LKTRTrace("%.*s, b%d, f %p\n", AuDLNPair(dentry), bindex, file);
+	/* d_revalidate() holds read_lock */
+	//DiMustWriteLock(dentry);
+	AuDebugOn(bindex < au_di(dentry)->di_bstart
+		  || bindex > au_di(dentry)->di_bend
+		  || !file
+		  || !h_file
+		  /* || au_test_wkq(current) */);
+
+	err = -ENOMEM;
+	if (hd->hd_intent_list) {
+		while (1) {
+			hf = au_find_h_intent(hd, file);
+			if (!hf)
+				break;
+#if 0 //def CONFIG_AUFS_DEBUG
+			au_debug_on();
+			DbgDentry(dentry);
+			DbgFile(hf);
+			au_debug_off();
+#endif
+			fput(hf);
+			AuWarn("freed hfile %.*s b%d left\n",
+			       AuDLNPair(dentry), bindex);
+		}
+	} else {
+		spin_lock(&hd->hd_lock);
+		if (!hd->hd_intent_list) {
+			hd->hd_intent_list
+				= kmalloc(sizeof(*hd->hd_intent_list),
+					  GFP_ATOMIC);
+			if (unlikely(!hd->hd_intent_list)) {
+				spin_unlock(&hd->hd_lock);
+				goto out;
+			}
+			INIT_LIST_HEAD(hd->hd_intent_list);
+		}
+		spin_unlock(&hd->hd_lock);
+	}
+
+	hdi = kmalloc(sizeof(*hdi), GFP_TEMPORARY);
+	if (unlikely(!hdi))
+		goto out;
+
+	err = 0;
+	//hdi->hdi_pid = current->pid;
+	hdi->hdi_file[AuIntent_AUFS] = file;
+	hdi->hdi_file[AuIntent_BRANCH] = h_file;
+	spin_lock(&hd->hd_lock);
+	list_add(&hdi->hdi_list, hd->hd_intent_list);
+	spin_unlock(&hd->hd_lock);
+	//AuDbgDentry(dentry);
+	//AuDbgFile(h_file);
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+int au_br_nfs_h_intent(struct file *nd_file, struct dentry *dentry,
+		       aufs_bindex_t bindex, struct nameidata *nd)
+{
+	int err;
+
+	AuTraceEnter();
+
+	err = 0;
+	if (!nd_file)
+		goto out;
+
+	AuDebugOn(!nd);
+	err = au_set_h_intent(dentry, bindex, nd->intent.open.file, nd_file);
+	//err = -1;
+	if (unlikely(err)) {
+		fput(nd_file);
+		au_set_h_dptr(dentry, bindex, NULL);
+		//todo: update bstart and bend?
+	}
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_hintent_put(struct au_hdentry *hd, int do_free)
+{
+	struct au_hdintent *hdi, *tmp;
+	struct file *hf;
+
+	if (unlikely(hd->hd_intent_list)) {
+		// no spin lock
+		list_for_each_entry_safe(hdi, tmp, hd->hd_intent_list,
+					 hdi_list) {
+			LKTRTrace("hdi %p\n", hdi);
+			hf = hdi->hdi_file[AuIntent_BRANCH];
+			if (unlikely(hf))
+				fput(hf);
+			//list_del(&hdi->hdi_list);
+			kfree(hdi);
+		}
+		if (do_free)
+			kfree(hd->hd_intent_list);
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+#if 0
+/* subset of nameidata */
+struct au_ndsub {
+	struct dentry	*dentry;
+	struct vfsmount *mnt;
+	unsigned int	flags;
+
+	union {
+		struct open_intent open;
+	} intent;
+};
+
+static void au_ndsub_restore(struct nameidata *nd, struct au_ndsub *save)
+{
+	nd->path.dentry = save->dentty;
+	nd->path.mnt = save->mnt;
+	nd->flags = save->flags;
+	nd->intent = save->intent;
+}
+#endif
+
+int au_fake_intent(/* struct au_ndsub *save,  */struct nameidata *nd,
+		   int perm)
+{
+	int err;
+
+	LKTRTrace("perm %d\n", perm);
+
+	err = 0;
+#if 0
+	nd->path.dentry = save->dentty;
+	nd->path.mnt = save->mnt;
+	save->flags = nd->flags;
+	save->intent = nd->intent;
+#endif
+
+	nd->intent.open.file = NULL;
+	if (nd->flags & LOOKUP_OPEN) {
+		err = -ENFILE;
+		nd->intent.open.file = get_empty_filp();
+		if (unlikely(!nd->intent.open.file)) {
+			//nd->intent.open.file = save->intent.open.file;
+			goto out;
+		}
+
+		err = 0;
+		if (!au_br_writable(perm)) {
+			nd->intent.open.flags = FMODE_READ
+				| au_file_roflags(nd->intent.open.flags);
+			nd->flags &= ~LOOKUP_CREATE;
+		}
+	}
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+int au_hin_after_reval(struct nameidata *nd, struct dentry *dentry,
+		       aufs_bindex_t bindex, struct file *file)
+{
+	int err;
+
+	LKTRTrace("nd %p, %.*s, b%d, f %d\n",
+		  nd, AuDLNPair(dentry), bindex, !!file);
+
+	err = 0;
+	if ((nd->flags & LOOKUP_OPEN)
+	    && nd->intent.open.file
+	    && !IS_ERR(nd->intent.open.file)) {
+		if (nd->intent.open.file->f_dentry) {
+			//AuDbgFile(nd->intent.open.file);
+			err = au_set_h_intent(dentry, bindex, file,
+					      nd->intent.open.file);
+			if (!err)
+				nd->intent.open.file = NULL;
+		}
+		if (unlikely(nd->intent.open.file))
+			put_filp(nd->intent.open.file);
+	}
+
+	return err;
+}
+
+#ifdef CONFIG_AUFS_DLGT
+struct au_lookup_hash_args {
+	struct dentry **errp;
+	struct qstr *name;
+	struct dentry *base;
+	struct nameidata *nd;
+};
+
+static void au_call_lookup_hash(void *args)
+{
+	struct au_lookup_hash_args *a = args;
+	*a->errp = vfsub__lookup_hash(a->name, a->base, a->nd);
+}
+
+static struct dentry *
+au_lkup_hash_dlgt(struct qstr *this, struct dentry *parent,
+		  struct nameidata *nd, unsigned int flags)
+{
+	struct dentry *dentry;
+	int dirperm1;
+
+	dirperm1 = au_ftest_ndx(flags, DIRPERM1);
+	if (!dirperm1 && !au_ftest_ndx(flags, DLGT))
+		dentry = vfsub__lookup_hash(this, parent, nd);
+	else {
+		int wkq_err;
+		struct au_lookup_hash_args args = {
+			.errp	= &dentry,
+			.name	= this,
+			.base	= parent,
+			.nd	= nd
+		};
+		wkq_err = au_wkq_wait(au_call_lookup_hash, &args,
+				      /*dlgt*/!dirperm1);
+		if (unlikely(wkq_err))
+			dentry = ERR_PTR(wkq_err);
+	}
+
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+#else
+static struct dentry *
+au_lkup_hash_dlgt(struct qstr *this, struct dentry *parent,
+		  struct nameidata *nd, unsigned int flags)
+{
+	return vfsub__lookup_hash(this, parent, nd);
+}
+#endif /* CONFIG_AUFS_DLGT */
+
+struct dentry *au_lkup_hash(const char *name, struct dentry *parent,
+			    int len, struct au_ndx *ndx)
+{
+	struct dentry *dentry;
+	char *p;
+	unsigned long hash;
+	struct qstr this;
+	unsigned int c;
+	struct nameidata tmp_nd, *ndo;
+	int err;
+
+	LKTRTrace("%.*s/%.*s\n", AuDLNPair(parent), len, name);
+
+	//todo: export and call __lookup_one_len() in fs/namei.c
+	dentry = ERR_PTR(-EACCES);
+	this.name = name;
+	this.len = len;
+	if (unlikely(!len))
+		goto out;
+
+	p = (void *)name;
+	hash = init_name_hash();
+	while (len--) {
+		c = *p++;
+		if (unlikely(c == '/' || c == '\0'))
+			goto out;
+		hash = partial_name_hash(c, hash);
+	}
+	this.hash = end_name_hash(hash);
+
+	ndo = ndx->nd;
+	if (ndo) {
+		tmp_nd = *ndo;
+		err = au_fake_intent(&tmp_nd, ndx->br->br_perm);
+		dentry = ERR_PTR(err);
+		if (unlikely(err))
+			goto out_intent;
+	} else
+		memset(&tmp_nd, 0, sizeof(tmp_nd));
+
+	tmp_nd.path.dentry = parent;
+	tmp_nd.path.mnt = ndx->nfsmnt;
+	path_get(&tmp_nd.path);
+	dentry = au_lkup_hash_dlgt(&this, parent, &tmp_nd, ndx->flags);
+	if (0 && !IS_ERR(dentry))
+		AuDbgDentry(dentry);
+	if (!IS_ERR(dentry)) {
+		/* why negative dentry for a new dir was unhashed? */
+		if (unlikely(d_unhashed(dentry)))
+			d_rehash(dentry);
+		if (tmp_nd.intent.open.file
+		    && tmp_nd.intent.open.file->f_dentry) {
+			//AuDbgFile(tmp_nd.intent.open.file);
+			ndx->nd_file = tmp_nd.intent.open.file;
+			tmp_nd.intent.open.file = NULL;
+			//au_br_get(ndx->br);
+		}
+	}
+	path_put(&tmp_nd.path);
+
+ out_intent:
+	if (tmp_nd.intent.open.file)
+		put_filp(tmp_nd.intent.open.file);
+ out:
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
-- 
1.4.4.4