Message-Id: <1237188040-11404-13-git-send-email-hooanon05@yahoo.co.jp>
Date:	Mon, 16 Mar 2009 16:20:24 +0900
From:	"J. R. Okajima" <hooanon05@...oo.co.jp>
To:	linux-kernel@...r.kernel.org
Cc:	linux-fsdevel@...r.kernel.org,
	"J. R. Okajima" <hooanon05@...oo.co.jp>
Subject: [RFC Aufs2 #2 12/28] aufs copy-up

initial commit
internal copy-up functions
see wbr_policy.c for copy-down

Signed-off-by: J. R. Okajima <hooanon05@...oo.co.jp>
---
 fs/aufs/cpup.c | 1028 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/aufs/cpup.h |   68 ++++
 2 files changed, 1096 insertions(+), 0 deletions(-)
 create mode 100644 fs/aufs/cpup.c
 create mode 100644 fs/aufs/cpup.h

diff --git a/fs/aufs/cpup.c b/fs/aufs/cpup.c
new file mode 100644
index 0000000..91808b1
--- /dev/null
+++ b/fs/aufs/cpup.c
@@ -0,0 +1,1028 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. 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.
+ */
+
+/*
+ * copy-up functions, see wbr_policy.c for copy-down
+ */
+
+#include <linux/fs_stack.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+void au_cpup_attr_flags(struct inode *dst, struct inode *src)
+{
+	const unsigned int mask = S_DEAD | S_SWAPFILE | S_PRIVATE
+		| S_NOATIME | S_NOCMTIME;
+
+	dst->i_flags |= src->i_flags & ~mask;
+	if (au_test_fs_notime(dst->i_sb))
+		dst->i_flags |= S_NOATIME | S_NOCMTIME;
+}
+
+void au_cpup_attr_timesizes(struct inode *inode)
+{
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, au_ibstart(inode));
+	fsstack_copy_attr_times(inode, h_inode);
+	vfsub_copy_inode_size(inode, h_inode);
+}
+
+void au_cpup_attr_nlink(struct inode *inode, int force)
+{
+	struct inode *h_inode;
+	struct super_block *sb;
+	aufs_bindex_t bindex, bend;
+
+	sb = inode->i_sb;
+	bindex = au_ibstart(inode);
+	h_inode = au_h_iptr(inode, bindex);
+	if (!force
+	    && !S_ISDIR(h_inode->i_mode)
+	    && au_opt_test(au_mntflags(sb), PLINK)
+	    && au_plink_test(inode))
+		return;
+
+	inode->i_nlink = h_inode->i_nlink;
+
+	/*
+	 * fewer nlink makes find(1) noisy, but larger nlink doesn't.
+	 * it may includes whplink directory.
+	 */
+	if (S_ISDIR(h_inode->i_mode)) {
+		bend = au_ibend(inode);
+		for (bindex++; bindex <= bend; bindex++) {
+			h_inode = au_h_iptr(inode, bindex);
+			if (h_inode)
+				au_add_nlink(inode, h_inode);
+		}
+	}
+}
+
+void au_cpup_attr_changeable(struct inode *inode)
+{
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, au_ibstart(inode));
+	inode->i_mode = h_inode->i_mode;
+	inode->i_uid = h_inode->i_uid;
+	inode->i_gid = h_inode->i_gid;
+	au_cpup_attr_timesizes(inode);
+	au_cpup_attr_flags(inode, h_inode);
+}
+
+void au_cpup_igen(struct inode *inode, struct inode *h_inode)
+{
+	struct au_iinfo *iinfo = au_ii(inode);
+
+	iinfo->ii_higen = h_inode->i_generation;
+	iinfo->ii_hsb1 = h_inode->i_sb;
+}
+
+void au_cpup_attr_all(struct inode *inode, int force)
+{
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, au_ibstart(inode));
+	au_cpup_attr_changeable(inode);
+	if (inode->i_nlink > 0)
+		au_cpup_attr_nlink(inode, force);
+	inode->i_rdev = h_inode->i_rdev;
+	inode->i_blkbits = h_inode->i_blkbits;
+	au_cpup_igen(inode, h_inode);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Note: dt_dentry and dt_h_dentry are not dget/dput-ed */
+
+/* keep the timestamps of the parent dir when cpup */
+void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
+		    struct path *h_path)
+{
+	struct inode *h_inode;
+
+	dt->dt_dentry = dentry;
+	dt->dt_h_path = *h_path;
+	h_inode = h_path->dentry->d_inode;
+	dt->dt_atime = h_inode->i_atime;
+	dt->dt_mtime = h_inode->i_mtime;
+	/* smp_mb(); */
+}
+
+void au_dtime_revert(struct au_dtime *dt)
+{
+	struct iattr attr;
+	int err;
+
+	attr.ia_atime = dt->dt_atime;
+	attr.ia_mtime = dt->dt_mtime;
+	attr.ia_valid = ATTR_FORCE | ATTR_MTIME | ATTR_MTIME_SET
+		| ATTR_ATIME | ATTR_ATIME_SET;
+
+	err = vfsub_notify_change(&dt->dt_h_path, &attr);
+	if (unlikely(err))
+		AuWarn("restoring timestamps failed(%d). ignored\n", err);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static noinline_for_stack
+int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src)
+{
+	int err, sbits;
+	struct iattr ia;
+	struct path h_path;
+	struct inode *h_isrc;
+
+	h_path.dentry = au_h_dptr(dst, bindex);
+	h_path.mnt = au_sbr_mnt(dst->d_sb, bindex);
+	h_isrc = h_src->d_inode;
+	ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID
+		| ATTR_ATIME | ATTR_MTIME
+		| ATTR_ATIME_SET | ATTR_MTIME_SET;
+	ia.ia_mode = h_isrc->i_mode;
+	ia.ia_uid = h_isrc->i_uid;
+	ia.ia_gid = h_isrc->i_gid;
+	ia.ia_atime = h_isrc->i_atime;
+	ia.ia_mtime = h_isrc->i_mtime;
+	sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
+	au_cpup_attr_flags(h_path.dentry->d_inode, h_isrc);
+	err = vfsub_notify_change(&h_path, &ia);
+
+	/* is this nfs only? */
+	if (!err && sbits && au_test_nfs(h_path.dentry->d_sb)) {
+		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
+		ia.ia_mode = h_isrc->i_mode;
+		err = vfsub_notify_change(&h_path, &ia);
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_do_copy_file(struct file *dst, struct file *src, loff_t len,
+			   char *buf, unsigned long blksize)
+{
+	int err;
+	size_t sz, rbytes, wbytes;
+	unsigned char all_zero;
+	char *p, *zp;
+	struct mutex *h_mtx;
+	/* reduce stack usage */
+	struct iattr *ia;
+
+	zp = page_address(ZERO_PAGE(0));
+	if (unlikely(!zp))
+		return -ENOMEM; /* possible? */
+
+	err = 0;
+	all_zero = 0;
+	while (len) {
+		AuDbg("len %lld\n", len);
+		sz = blksize;
+		if (len < blksize)
+			sz = len;
+
+		rbytes = 0;
+		/* todo: signal_pending? */
+		while (!rbytes || err == -EAGAIN || err == -EINTR) {
+			rbytes = vfsub_read_k(src, buf, sz, &src->f_pos);
+			err = rbytes;
+		}
+		if (unlikely(err < 0))
+			break;
+
+		all_zero = 0;
+		if (len >= rbytes && rbytes == blksize)
+			all_zero = !memcmp(buf, zp, rbytes);
+		if (!all_zero) {
+			wbytes = rbytes;
+			p = buf;
+			while (wbytes) {
+				size_t b;
+
+				b = vfsub_write_k(dst, p, wbytes, &dst->f_pos);
+				err = b;
+				/* todo: signal_pending? */
+				if (unlikely(err == -EAGAIN || err == -EINTR))
+					continue;
+				if (unlikely(err < 0))
+					break;
+				wbytes -= b;
+				p += b;
+			}
+		} else {
+			loff_t res;
+
+			AuLabel(hole);
+			res = vfsub_llseek(dst, rbytes, SEEK_CUR);
+			err = res;
+			if (unlikely(res < 0))
+				break;
+		}
+		len -= rbytes;
+		err = 0;
+	}
+
+	/* the last block may be a hole */
+	if (!err && all_zero) {
+		AuLabel(last hole);
+
+		err = 1;
+		if (au_test_nfs(dst->f_dentry->d_sb)) {
+			/* nfs requires this step to make last hole */
+			/* is this only nfs? */
+			do {
+				/* todo: signal_pending? */
+				err = vfsub_write_k(dst, "\0", 1, &dst->f_pos);
+			} while (err == -EAGAIN || err == -EINTR);
+			if (err == 1)
+				dst->f_pos--;
+		}
+
+		if (err == 1) {
+			ia = (void *)buf;
+			ia->ia_size = dst->f_pos;
+			ia->ia_valid = ATTR_SIZE | ATTR_FILE;
+			ia->ia_file = dst;
+			h_mtx = &dst->f_dentry->d_inode->i_mutex;
+			mutex_lock_nested(h_mtx, AuLsc_I_CHILD2);
+			err = vfsub_notify_change(&dst->f_path, ia);
+			mutex_unlock(h_mtx);
+		}
+	}
+
+	return err;
+}
+
+int au_copy_file(struct file *dst, struct file *src, loff_t len)
+{
+	int err;
+	unsigned long blksize;
+	unsigned char do_kfree;
+	char *buf;
+
+	err = -ENOMEM;
+	blksize = dst->f_dentry->d_sb->s_blocksize;
+	if (!blksize || PAGE_SIZE < blksize)
+		blksize = PAGE_SIZE;
+	AuDbg("blksize %lu\n", blksize);
+	do_kfree = (blksize != PAGE_SIZE && blksize >= sizeof(struct iattr *));
+	if (do_kfree)
+		buf = kmalloc(blksize, GFP_NOFS);
+	else
+		buf = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!buf))
+		goto out;
+
+	if (len > (1 << 22))
+		AuDbg("copying a large file %lld\n", (long long)len);
+
+	src->f_pos = 0;
+	dst->f_pos = 0;
+	err = au_do_copy_file(dst, src, len, buf, blksize);
+	if (do_kfree)
+		kfree(buf);
+	else
+		free_page((unsigned long)buf);
+
+ out:
+	return err;
+}
+
+/*
+ * to support a sparse file which is opened with O_APPEND,
+ * we need to close the file.
+ */
+static int au_cp_regular(struct dentry *dentry, aufs_bindex_t bdst,
+			aufs_bindex_t bsrc, loff_t len)
+{
+	int err, i;
+	enum { SRC, DST };
+	struct {
+		aufs_bindex_t bindex;
+		unsigned int flags;
+		struct dentry *dentry;
+		struct file *file;
+		void *label, *label_file;
+	} *f, file[] = {
+		{
+			.bindex = bsrc,
+			.flags = O_RDONLY | O_NOATIME | O_LARGEFILE,
+			.file = NULL,
+			.label = &&out,
+			.label_file = &&out_src
+		},
+		{
+			.bindex = bdst,
+			.flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
+			.file = NULL,
+			.label = &&out_src,
+			.label_file = &&out_dst
+		}
+	};
+	struct super_block *sb;
+
+	/* bsrc branch can be ro/rw. */
+	sb = dentry->d_sb;
+	f = file;
+	for (i = 0; i < 2; i++, f++) {
+		f->dentry = au_h_dptr(dentry, f->bindex);
+		f->file = au_h_open(dentry, f->bindex, f->flags, /*file*/NULL);
+		err = PTR_ERR(f->file);
+		if (IS_ERR(f->file))
+			goto *f->label;
+		err = -EINVAL;
+		if (unlikely(!f->file->f_op))
+			goto *f->label_file;
+	}
+
+	/* try stopping to update while we copyup */
+	IMustLock(file[SRC].dentry->d_inode);
+	err = au_copy_file(file[DST].file, file[SRC].file, len);
+
+ out_dst:
+	fput(file[DST].file);
+	au_sbr_put(sb, file[DST].bindex);
+ out_src:
+	fput(file[SRC].file);
+	au_sbr_put(sb, file[SRC].bindex);
+ out:
+	return err;
+}
+
+static int au_do_cpup_regular(struct dentry *dentry, aufs_bindex_t bdst,
+			      aufs_bindex_t bsrc, loff_t len,
+			      struct inode *h_dir, struct path *h_path)
+{
+	int err, rerr;
+	loff_t l;
+
+	err = 0;
+	l = i_size_read(au_h_iptr(dentry->d_inode, bsrc));
+	if (len == -1 || l < len)
+		len = l;
+	if (len)
+		err = au_cp_regular(dentry, bdst, bsrc, len);
+	if (!err)
+		goto out; /* success */
+
+	rerr = vfsub_unlink(h_dir, h_path, /*force*/0);
+	if (rerr) {
+		AuIOErr("failed unlinking cpup-ed %.*s(%d, %d)\n",
+			AuDLNPair(h_path->dentry), err, rerr);
+		err = -EIO;
+	}
+
+ out:
+	return err;
+}
+
+static int au_do_cpup_symlink(struct path *h_path, struct dentry *h_src,
+			      struct inode *h_dir)
+{
+	int err, symlen;
+	mm_segment_t old_fs;
+	char *sym;
+
+	err = -ENOSYS;
+	if (unlikely(!h_src->d_inode->i_op->readlink))
+		goto out;
+
+	err = -ENOMEM;
+	sym = __getname();
+	if (unlikely(!sym))
+		goto out;
+
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	symlen = h_src->d_inode->i_op->readlink(h_src, (char __user *)sym,
+						PATH_MAX);
+	err = symlen;
+	set_fs(old_fs);
+
+	if (symlen > 0) {
+		sym[symlen] = 0;
+		err = vfsub_symlink(h_dir, h_path, sym);
+	}
+	__putname(sym);
+
+ out:
+	return err;
+}
+
+/* return with the lower dst inode is locked */
+static noinline_for_stack
+int cpup_entry(struct dentry *dentry, aufs_bindex_t bdst,
+	       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+	       struct dentry *dst_parent)
+{
+	int err;
+	umode_t mode;
+	unsigned int mnt_flags;
+	unsigned char isdir;
+	const unsigned char do_dt = !!au_ftest_cpup(flags, DTIME);
+	struct au_dtime dt;
+	struct path h_path;
+	struct dentry *h_src, *h_dst, *h_parent;
+	struct inode *h_inode, *h_dir;
+	struct super_block *sb;
+
+	/* bsrc branch can be ro/rw. */
+	h_src = au_h_dptr(dentry, bsrc);
+	h_inode = h_src->d_inode;
+	AuDebugOn(h_inode != au_h_iptr(dentry->d_inode, bsrc));
+
+	/* try stopping to be referenced while we are creating */
+	h_dst = au_h_dptr(dentry, bdst);
+	h_parent = h_dst->d_parent; /* dir inode is locked */
+	h_dir = h_parent->d_inode;
+	IMustLock(h_dir);
+	AuDebugOn(h_parent != h_dst->d_parent);
+
+	sb = dentry->d_sb;
+	h_path.mnt = au_sbr_mnt(sb, bdst);
+	if (do_dt) {
+		h_path.dentry = h_parent;
+		au_dtime_store(&dt, dst_parent, &h_path);
+	}
+	h_path.dentry = h_dst;
+
+	isdir = 0;
+	mode = h_inode->i_mode;
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		/* try stopping to update while we are referencing */
+		IMustLock(h_inode);
+		err = vfsub_create(h_dir, &h_path, mode | S_IWUSR);
+		if (!err)
+			err = au_do_cpup_regular
+				(dentry, bdst, bsrc, len,
+				 au_h_iptr(dst_parent->d_inode, bdst), &h_path);
+		break;
+	case S_IFDIR:
+		isdir = 1;
+		err = vfsub_mkdir(h_dir, &h_path, mode);
+		if (!err) {
+			/*
+			 * strange behaviour from the users view,
+			 * particularry setattr case
+			 */
+			if (au_ibstart(dst_parent->d_inode) == bdst)
+				au_cpup_attr_nlink(dst_parent->d_inode,
+						   /*force*/1);
+			au_cpup_attr_nlink(dentry->d_inode, /*force*/1);
+		}
+		break;
+	case S_IFLNK:
+		err = au_do_cpup_symlink(&h_path, h_src, h_dir);
+		break;
+	case S_IFCHR:
+	case S_IFBLK:
+		AuDebugOn(!capable(CAP_MKNOD));
+		/*FALLTHROUGH*/
+	case S_IFIFO:
+	case S_IFSOCK:
+		err = vfsub_mknod(h_dir, &h_path, mode, h_inode->i_rdev);
+		break;
+	default:
+		AuIOErr("Unknown inode type 0%o\n", mode);
+		err = -EIO;
+	}
+
+	mnt_flags = au_mntflags(sb);
+	if (!au_opt_test(mnt_flags, UDBA_NONE)
+	    && !isdir
+	    && au_opt_test(mnt_flags, XINO)
+	    && h_inode->i_nlink == 1
+	    /* todo: unnecessary? */
+	    /* && dentry->d_inode->i_nlink == 1 */
+	    && bdst < bsrc
+	    && !au_ftest_cpup(flags, KEEPLINO))
+		au_xino_write0(sb, bsrc, h_inode->i_ino, /*ino*/0);
+		/* ignore this error */
+
+	if (do_dt)
+		au_dtime_revert(&dt);
+	return err;
+}
+
+/*
+ * copyup the @dentry from @bsrc to @bdst.
+ * the caller must set the both of lower dentries.
+ * @len is for truncating when it is -1 copyup the entire file.
+ * in link/rename cases, @dst_parent may be different from the real one.
+ */
+static int au_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+			  aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+			  struct dentry *dst_parent)
+{
+	int err, rerr;
+	aufs_bindex_t old_ibstart;
+	unsigned char isdir, plink;
+	struct au_dtime dt;
+	struct path h_path;
+	struct dentry *h_src, *h_dst, *h_parent;
+	struct inode *dst_inode, *h_dir, *inode;
+	struct super_block *sb;
+
+	AuDebugOn(bsrc <= bdst);
+
+	sb = dentry->d_sb;
+	h_path.mnt = au_sbr_mnt(sb, bdst);
+	h_dst = au_h_dptr(dentry, bdst);
+	h_parent = h_dst->d_parent; /* dir inode is locked */
+	h_dir = h_parent->d_inode;
+	IMustLock(h_dir);
+
+	h_src = au_h_dptr(dentry, bsrc);
+	inode = dentry->d_inode;
+
+	if (!dst_parent)
+		dst_parent = dget_parent(dentry);
+	else
+		dget(dst_parent);
+
+	plink = !!au_opt_test(au_mntflags(sb), PLINK);
+	dst_inode = au_h_iptr(inode, bdst);
+	if (dst_inode) {
+		if (unlikely(!plink)) {
+			err = -EIO;
+			AuIOErr("i%lu exists on a upper branch "
+				"but plink is disabled\n", inode->i_ino);
+			goto out;
+		}
+
+		if (dst_inode->i_nlink) {
+			const int do_dt = au_ftest_cpup(flags, DTIME);
+
+			h_src = au_plink_lkup(inode, bdst);
+			err = PTR_ERR(h_src);
+			if (IS_ERR(h_src))
+				goto out;
+			if (unlikely(!h_src->d_inode)) {
+				err = -EIO;
+				AuIOErr("i%lu exists on a upper branch "
+					"but plink is broken\n", inode->i_ino);
+				dput(h_src);
+				goto out;
+			}
+
+			if (do_dt) {
+				h_path.dentry = h_parent;
+				au_dtime_store(&dt, dst_parent, &h_path);
+			}
+			h_path.dentry = h_dst;
+			err = vfsub_link(h_src, h_dir, &h_path);
+			if (do_dt)
+				au_dtime_revert(&dt);
+			dput(h_src);
+			goto out;
+		} else
+			/* todo: cpup_wh_file? */
+			/* udba work */
+			au_update_brange(inode, 1);
+	}
+
+	old_ibstart = au_ibstart(inode);
+	err = cpup_entry(dentry, bdst, bsrc, len, flags, dst_parent);
+	if (unlikely(err))
+		goto out;
+	dst_inode = h_dst->d_inode;
+	mutex_lock_nested(&dst_inode->i_mutex, AuLsc_I_CHILD2);
+
+	err = cpup_iattr(dentry, bdst, h_src);
+	isdir = S_ISDIR(dst_inode->i_mode);
+	if (!err) {
+		if (bdst < old_ibstart)
+			au_set_ibstart(inode, bdst);
+		au_set_h_iptr(inode, bdst, au_igrab(dst_inode),
+			      au_hi_flags(inode, isdir));
+		mutex_unlock(&dst_inode->i_mutex);
+		if (!isdir
+		    && h_src->d_inode->i_nlink > 1
+		    && plink)
+			au_plink_append(inode, bdst, h_dst);
+		goto out; /* success */
+	}
+
+	/* revert */
+	h_path.dentry = h_parent;
+	mutex_unlock(&dst_inode->i_mutex);
+	au_dtime_store(&dt, dst_parent, &h_path);
+	h_path.dentry = h_dst;
+	if (!isdir)
+		rerr = vfsub_unlink(h_dir, &h_path, /*force*/0);
+	else
+		rerr = vfsub_rmdir(h_dir, &h_path);
+	au_dtime_revert(&dt);
+	if (rerr) {
+		AuIOErr("failed removing broken entry(%d, %d)\n", err, rerr);
+		err = -EIO;
+	}
+
+ out:
+	dput(dst_parent);
+	return err;
+}
+
+struct au_cpup_single_args {
+	int *errp;
+	struct dentry *dentry;
+	aufs_bindex_t bdst, bsrc;
+	loff_t len;
+	unsigned int flags;
+	struct dentry *dst_parent;
+};
+
+static void au_call_cpup_single(void *args)
+{
+	struct au_cpup_single_args *a = args;
+	*a->errp = au_cpup_single(a->dentry, a->bdst, a->bsrc, a->len,
+				  a->flags, a->dst_parent);
+}
+
+int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+		       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+		       struct dentry *dst_parent)
+{
+	int err, wkq_err;
+	umode_t mode;
+	struct dentry *h_dentry;
+
+	h_dentry = au_h_dptr(dentry, bsrc);
+	mode = h_dentry->d_inode->i_mode & S_IFMT;
+	if ((mode != S_IFCHR && mode != S_IFBLK)
+	    || capable(CAP_MKNOD))
+		err = au_cpup_single(dentry, bdst, bsrc, len, flags,
+				     dst_parent);
+	else {
+		struct au_cpup_single_args args = {
+			.errp		= &err,
+			.dentry		= dentry,
+			.bdst		= bdst,
+			.bsrc		= bsrc,
+			.len		= len,
+			.flags		= flags,
+			.dst_parent	= dst_parent
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_single, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	return err;
+}
+
+/*
+ * copyup the @dentry from the first active lower branch to @bdst,
+ * using au_cpup_single().
+ */
+static int au_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+			  unsigned int flags)
+{
+	int err;
+	aufs_bindex_t bsrc, bend;
+
+	bend = au_dbend(dentry);
+	for (bsrc = bdst + 1; bsrc <= bend; bsrc++)
+		if (au_h_dptr(dentry, bsrc))
+			break;
+
+	err = au_lkup_neg(dentry, bdst);
+	if (!err) {
+		err = au_cpup_single(dentry, bdst, bsrc, len, flags, NULL);
+		if (!err)
+			return 0; /* success */
+
+		/* revert */
+		au_set_h_dptr(dentry, bdst, NULL);
+		au_set_dbstart(dentry, bsrc);
+	}
+
+	return err;
+}
+
+struct au_cpup_simple_args {
+	int *errp;
+	struct dentry *dentry;
+	aufs_bindex_t bdst;
+	loff_t len;
+	unsigned int flags;
+};
+
+static void au_call_cpup_simple(void *args)
+{
+	struct au_cpup_simple_args *a = args;
+	*a->errp = au_cpup_simple(a->dentry, a->bdst, a->len, a->flags);
+}
+
+int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		       unsigned int flags)
+{
+	int err, wkq_err;
+	unsigned char do_sio;
+	struct dentry *parent;
+	struct inode *h_dir;
+
+	parent = dget_parent(dentry);
+	h_dir = au_h_iptr(parent->d_inode, bdst);
+	do_sio = !!au_test_h_perm_sio(h_dir, MAY_EXEC | MAY_WRITE);
+	if (!do_sio) {
+		/*
+		 * testing CAP_MKNOD is for generic fs,
+		 * but CAP_FSETID is for xfs only, currently.
+		 */
+		umode_t mode = dentry->d_inode->i_mode;
+		do_sio = (((mode & (S_IFCHR | S_IFBLK))
+			   && !capable(CAP_MKNOD))
+			  || ((mode & (S_ISUID | S_ISGID))
+			      && !capable(CAP_FSETID)));
+	}
+	if (!do_sio)
+		err = au_cpup_simple(dentry, bdst, len, flags);
+	else {
+		struct au_cpup_simple_args args = {
+			.errp		= &err,
+			.dentry		= dentry,
+			.bdst		= bdst,
+			.len		= len,
+			.flags		= flags
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_simple, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	dput(parent);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * copyup the deleted file for writing.
+ */
+static int au_do_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *wh_dentry, struct file *file,
+			 loff_t len)
+{
+	int err;
+	aufs_bindex_t bstart;
+	struct au_dinfo *dinfo;
+	struct dentry *h_d_dst, *h_d_start;
+
+	dinfo = au_di(dentry);
+	bstart = dinfo->di_bstart;
+	h_d_dst = dinfo->di_hdentry[0 + bdst].hd_dentry;
+	dinfo->di_bstart = bdst;
+	dinfo->di_hdentry[0 + bdst].hd_dentry = wh_dentry;
+	h_d_start = dinfo->di_hdentry[0 + bstart].hd_dentry;
+	if (file)
+		dinfo->di_hdentry[0 + bstart].hd_dentry
+			= au_h_fptr(file, au_fbstart(file))->f_dentry;
+	err = au_cpup_single(dentry, bdst, bstart, len, !AuCpup_DTIME,
+			     /*h_parent*/NULL);
+	if (!err && file) {
+		err = au_reopen_nondir(file);
+		dinfo->di_hdentry[0 + bstart].hd_dentry = h_d_start;
+	}
+	dinfo->di_hdentry[0 + bdst].hd_dentry = h_d_dst;
+	dinfo->di_bstart = bstart;
+
+	return err;
+}
+
+static int au_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		      struct file *file)
+{
+	int err;
+	struct au_dtime dt;
+	struct dentry *parent, *h_parent, *wh_dentry;
+	struct au_branch *br;
+	struct path h_path;
+
+	br = au_sbr(dentry->d_sb, bdst);
+	parent = dget_parent(dentry);
+	h_parent = au_h_dptr(parent, bdst);
+	wh_dentry = au_whtmp_lkup(h_parent, br, &dentry->d_name);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out;
+
+	h_path.dentry = h_parent;
+	h_path.mnt = br->br_mnt;
+	au_dtime_store(&dt, parent, &h_path);
+	err = au_do_cpup_wh(dentry, bdst, wh_dentry, file, len);
+	if (unlikely(err))
+		goto out_wh;
+
+	dget(wh_dentry);
+	h_path.dentry = wh_dentry;
+	err = vfsub_unlink(h_parent->d_inode, &h_path, /*force*/0);
+	if (unlikely(err)) {
+		AuIOErr("failed remove copied-up tmp file %.*s(%d)\n",
+			AuDLNPair(wh_dentry), err);
+		err = -EIO;
+	}
+	au_dtime_revert(&dt);
+	au_set_hi_wh(dentry->d_inode, bdst, wh_dentry);
+
+ out_wh:
+	dput(wh_dentry);
+ out:
+	dput(parent);
+	return err;
+}
+
+struct au_cpup_wh_args {
+	int *errp;
+	struct dentry *dentry;
+	aufs_bindex_t bdst;
+	loff_t len;
+	struct file *file;
+};
+
+static void au_call_cpup_wh(void *args)
+{
+	struct au_cpup_wh_args *a = args;
+	*a->errp = au_cpup_wh(a->dentry, a->bdst, a->len, a->file);
+}
+
+int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		   struct file *file)
+{
+	int err, wkq_err;
+	struct dentry *parent, *h_orph, *h_parent, *h_dentry;
+	struct inode *dir, *h_dir, *h_tmpdir, *h_inode;
+	struct au_wbr *wbr;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	h_orph = NULL;
+	h_parent = NULL;
+	h_dir = au_igrab(au_h_iptr(dir, bdst));
+	h_tmpdir = h_dir;
+	if (!h_dir->i_nlink) {
+		wbr = au_sbr(dentry->d_sb, bdst)->br_wbr;
+		h_orph = wbr->wbr_orph;
+
+		h_parent = dget(au_h_dptr(parent, bdst));
+		au_set_h_dptr(parent, bdst, NULL);
+		au_set_h_dptr(parent, bdst, dget(h_orph));
+		h_tmpdir = h_orph->d_inode;
+		au_set_h_iptr(dir, bdst, NULL, 0);
+		au_set_h_iptr(dir, bdst, au_igrab(h_tmpdir), /*flags*/0);
+
+		/* this temporary unlock is safe */
+		if (file)
+			h_dentry = au_h_fptr(file, au_fbstart(file))->f_dentry;
+		else
+			h_dentry = au_h_dptr(dentry, au_dbstart(dentry));
+		h_inode = h_dentry->d_inode;
+		IMustLock(h_inode);
+		mutex_unlock(&h_inode->i_mutex);
+		mutex_lock_nested(&h_tmpdir->i_mutex, AuLsc_I_PARENT2);
+		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	}
+
+	if (!au_test_h_perm_sio(h_tmpdir, MAY_EXEC | MAY_WRITE))
+		err = au_cpup_wh(dentry, bdst, len, file);
+	else {
+		struct au_cpup_wh_args args = {
+			.errp	= &err,
+			.dentry	= dentry,
+			.bdst	= bdst,
+			.len	= len,
+			.file	= file
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_wh, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	if (h_orph) {
+		mutex_unlock(&h_tmpdir->i_mutex);
+		au_set_h_iptr(dir, bdst, NULL, 0);
+		au_set_h_iptr(dir, bdst, au_igrab(h_dir), /*flags*/0);
+		au_set_h_dptr(parent, bdst, NULL);
+		au_set_h_dptr(parent, bdst, h_parent);
+	}
+	iput(h_dir);
+	dput(parent);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * generic routine for both of copy-up and copy-down.
+ */
+/* cf. revalidate function in file.c */
+int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
+	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *h_parent, void *arg),
+	       void *arg)
+{
+	int err;
+	struct au_pin pin;
+	struct dentry *d, *parent, *h_parent, *real_parent;
+
+	err = 0;
+	parent = dget_parent(dentry);
+	if (IS_ROOT(parent))
+		goto out;
+
+	au_pin_init(&pin, dentry, bdst, AuLsc_DI_PARENT2, AuLsc_I_PARENT2,
+		    au_opt_udba(dentry->d_sb), AuPin_MNT_WRITE);
+
+	/* do not use au_dpage */
+	real_parent = parent;
+	while (1) {
+		dput(parent);
+		parent = dget_parent(dentry);
+		h_parent = au_h_dptr(parent, bdst);
+		if (h_parent)
+			goto out; /* success */
+
+		/* find top dir which is necessary to cpup */
+		do {
+			d = parent;
+			dput(parent);
+			parent = dget_parent(d);
+			di_read_lock_parent3(parent, !AuLock_IR);
+			h_parent = au_h_dptr(parent, bdst);
+			di_read_unlock(parent, !AuLock_IR);
+		} while (!h_parent);
+
+		if (d != real_parent)
+			di_write_lock_child3(d);
+
+		/* somebody else might create while we were sleeping */
+		if (!au_h_dptr(d, bdst) || !au_h_dptr(d, bdst)->d_inode) {
+			if (au_h_dptr(d, bdst))
+				au_update_dbstart(d);
+
+			au_pin_set_dentry(&pin, d);
+			err = au_do_pin(&pin);
+			if (!err) {
+				err = cp(d, bdst, h_parent, arg);
+				au_unpin(&pin);
+			}
+		}
+
+		if (d != real_parent)
+			di_write_unlock(d);
+		if (unlikely(err))
+			break;
+	}
+
+ out:
+	dput(parent);
+	return err;
+}
+
+static int au_cpup_dir(struct dentry *dentry, aufs_bindex_t bdst,
+		       struct dentry *h_parent __maybe_unused ,
+		       void *arg __maybe_unused)
+{
+	return au_sio_cpup_simple(dentry, bdst, -1, AuCpup_DTIME);
+}
+
+int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+	return au_cp_dirs(dentry, bdst, au_cpup_dir, NULL);
+}
+
+int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+	int err;
+	struct dentry *parent;
+	struct inode *dir;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	err = 0;
+	if (au_h_iptr(dir, bdst))
+		goto out;
+
+	di_read_unlock(parent, AuLock_IR);
+	di_write_lock_parent(parent);
+	/* someone else might change our inode while we were sleeping */
+	if (!au_h_iptr(dir, bdst))
+		err = au_cpup_dirs(dentry, bdst);
+	di_downgrade_lock(parent, AuLock_IR);
+
+ out:
+	dput(parent);
+	return err;
+}
diff --git a/fs/aufs/cpup.h b/fs/aufs/cpup.h
new file mode 100644
index 0000000..240014a
--- /dev/null
+++ b/fs/aufs/cpup.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. 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.
+ */
+
+/*
+ * copy-up/down functions
+ */
+
+#ifndef __AUFS_CPUP_H__
+#define __AUFS_CPUP_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/aufs_type.h>
+
+void au_cpup_attr_flags(struct inode *dst, struct inode *src);
+void au_cpup_attr_timesizes(struct inode *inode);
+void au_cpup_attr_nlink(struct inode *inode, int force);
+void au_cpup_attr_changeable(struct inode *inode);
+void au_cpup_igen(struct inode *inode, struct inode *h_inode);
+void au_cpup_attr_all(struct inode *inode, int force);
+
+/* ---------------------------------------------------------------------- */
+
+/* cpup flags */
+#define AuCpup_DTIME	1		/* do dtime_store/revert */
+#define AuCpup_KEEPLINO	(1 << 1)	/* do not clear the lower xino,
+					   for link(2) */
+#define au_ftest_cpup(flags, name)	((flags) & AuCpup_##name)
+#define au_fset_cpup(flags, name)	{ (flags) |= AuCpup_##name; }
+#define au_fclr_cpup(flags, name)	{ (flags) &= ~AuCpup_##name; }
+
+int au_copy_file(struct file *dst, struct file *src, loff_t len);
+int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+		       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+		       struct dentry *dst_parent);
+int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		       unsigned int flags);
+int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		   struct file *file);
+
+int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
+	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *h_parent, void *arg),
+	       void *arg);
+int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+
+/* ---------------------------------------------------------------------- */
+
+/* keep timestamps when copyup */
+struct au_dtime {
+	struct dentry *dt_dentry;
+	struct path dt_h_path;
+	struct timespec dt_atime, dt_mtime;
+};
+void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
+		    struct path *h_path);
+void au_dtime_revert(struct au_dtime *dt);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_CPUP_H__ */
-- 
1.6.1.284.g5dc13

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