openwrt/target/linux/generic/patches-4.9/140-jffs2-use-.rename2-and-...

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From: Felix Fietkau <nbd@nbd.name>
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@nbd.name>
---
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -756,6 +756,24 @@ 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,
unsigned int flags)
@@ -766,7 +784,7 @@ static int jffs2_rename (struct inode *o
uint8_t type;
uint32_t now;
- if (flags & ~RENAME_NOREPLACE)
+ if (flags & ~(RENAME_NOREPLACE|RENAME_WHITEOUT))
return -EINVAL;
/* The VFS will check for us and prevent trying to rename a
@@ -832,9 +850,14 @@ static int jffs2_rename (struct inode *o
if (d_is_dir(old_dentry) && !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 */