kernel: add jffs2 RENAME_WHITEOUT support, fixes overlayfs renames (#19432)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 45362

1 files changed, 86 insertions, 0 deletions

diff --git a/target/linux/generic/patches-3.18/110-jffs2-use-.rename2-and-add-RENAME_WHITEOUT-support.patch b/target/linux/generic/patches-3.18/110-jffs2-use-.rename2-and-add-RENAME_WHITEOUT-support.patch
new file mode 100644
index 0000000..4ffa3c2
--- /dev/null
+++ b/target/linux/generic/patches-3.18/110-jffs2-use-.rename2-and-add-RENAME_WHITEOUT-support.patch
@@ -0,0 +1,86 @@
+From: Felix Fietkau <nbd@openwrt.org>
+Date: Fri, 10 Apr 2015 13:35:29 +0200
+Subject: [PATCH] jffs2: use .rename2 and add RENAME_WHITEOUT support
+
+It is required for renames on overlayfs
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+---
+
+--- a/fs/jffs2/dir.c
++++ b/fs/jffs2/dir.c
+@@ -35,7 +35,7 @@ static int jffs2_mkdir (struct inode *,s
+ static int jffs2_rmdir (struct inode *,struct dentry *);
+ static int jffs2_mknod (struct inode *,struct dentry *,umode_t,dev_t);
+ static int jffs2_rename (struct inode *, struct dentry *,
+-			 struct inode *, struct dentry *);
++			 struct inode *, struct dentry *, unsigned int);
+ 
+ const struct file_operations jffs2_dir_operations =
+ {
+@@ -57,7 +57,7 @@ const struct inode_operations jffs2_dir_
+ 	.mkdir =	jffs2_mkdir,
+ 	.rmdir =	jffs2_rmdir,
+ 	.mknod =	jffs2_mknod,
+-	.rename =	jffs2_rename,
++	.rename2 =	jffs2_rename,
+ 	.get_acl =	jffs2_get_acl,
+ 	.set_acl =	jffs2_set_acl,
+ 	.setattr =	jffs2_setattr,
+@@ -756,8 +756,27 @@ static int jffs2_mknod (struct inode *di
+ 	return ret;
+ }
+ 
++static int jffs2_whiteout(struct inode *old_dir, struct dentry *old_dentry)
++{
++	struct dentry *wh;
++	int err;
++
++	wh = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
++	if (!wh)
++		return -ENOMEM;
++
++	err = jffs2_mknod(old_dir, wh, S_IFCHR | WHITEOUT_MODE,
++			  WHITEOUT_DEV);
++	if (err)
++		return err;
++
++	d_rehash(wh);
++	return 0;
++}
++
+ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
+-			 struct inode *new_dir_i, struct dentry *new_dentry)
++			 struct inode *new_dir_i, struct dentry *new_dentry,
++			 unsigned int flags)
+ {
+ 	int ret;
+ 	struct jffs2_sb_info *c = JFFS2_SB_INFO(old_dir_i->i_sb);
+@@ -765,6 +784,9 @@ static int jffs2_rename (struct inode *o
+ 	uint8_t type;
+ 	uint32_t now;
+ 
++	if (flags & ~RENAME_WHITEOUT)
++		return -EINVAL;
++
+ 	/* The VFS will check for us and prevent trying to rename a
+ 	 * file over a directory and vice versa, but if it's a directory,
+ 	 * the VFS can't check whether the victim is empty. The filesystem
+@@ -828,9 +850,14 @@ static int jffs2_rename (struct inode *o
+ 	if (S_ISDIR(old_dentry->d_inode->i_mode) && !victim_f)
+ 		inc_nlink(new_dir_i);
+ 
+-	/* Unlink the original */
+-	ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
+-			      old_dentry->d_name.name, old_dentry->d_name.len, NULL, now);
++	if (flags & RENAME_WHITEOUT)
++		/* Replace with whiteout */
++		ret = jffs2_whiteout(old_dir_i, old_dentry);
++	else
++		/* Unlink the original */
++		ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
++				      old_dentry->d_name.name,
++				      old_dentry->d_name.len, NULL, now);
+ 
+ 	/* We don't touch inode->i_nlink */
+