add jffs2 whiteout support (necessary for using it with union mounts)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@17745 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 186 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch b/target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch
new file mode 100644
index 000000000..72a428237
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch
@@ -0,0 +1,186 @@
+--- a/fs/jffs2/dir.c
++++ b/fs/jffs2/dir.c
+@@ -34,6 +34,9 @@
+ static int jffs2_rename (struct inode *, struct dentry *,
+ 			 struct inode *, struct dentry *);
+ 
++static int jffs2_whiteout (struct inode *, struct dentry *, struct dentry *);
++static int jffs2_fallthru (struct inode *, struct dentry *);
++
+ const struct file_operations jffs2_dir_operations =
+ {
+ 	.read =		generic_read_dir,
+@@ -55,6 +58,8 @@
+ 	.rmdir =	jffs2_rmdir,
+ 	.mknod =	jffs2_mknod,
+ 	.rename =	jffs2_rename,
++	.fallthru =     jffs2_fallthru,
++	.whiteout =     jffs2_whiteout,
+ 	.permission =	jffs2_permission,
+ 	.setattr =	jffs2_setattr,
+ 	.setxattr =	jffs2_setxattr,
+@@ -98,8 +103,21 @@
+ 			fd = fd_list;
+ 		}
+ 	}
+-	if (fd)
+-		ino = fd->ino;
++	if (fd) {
++		spin_lock(&target->d_lock);
++		switch(fd->type) {
++		case DT_WHT:
++			target->d_flags |= DCACHE_WHITEOUT;
++			break;
++		case DT_UNKNOWN:
++			target->d_flags |= DCACHE_FALLTHRU;
++			break;
++		default:
++			ino = fd->ino;
++			break;
++		}
++		spin_unlock(&target->d_lock);
++	}
+ 	mutex_unlock(&dir_f->sem);
+ 	if (ino) {
+ 		inode = jffs2_iget(dir_i->i_sb, ino);
+@@ -155,7 +173,9 @@
+ 				  fd->name, fd->ino, fd->type, curofs, offset));
+ 			continue;
+ 		}
+-		if (!fd->ino) {
++		if (fd->type == DT_UNKNOWN)
++			fd->ino = 100; /* XXX: arbitrary */
++		else if (!fd->ino && (fd->type != DT_WHT)) {
+ 			D2(printk(KERN_DEBUG "Skipping deletion dirent \"%s\"\n", fd->name));
+ 			offset++;
+ 			continue;
+@@ -498,6 +518,11 @@
+ 		return PTR_ERR(inode);
+ 	}
+ 
++	if (dentry->d_flags & DCACHE_WHITEOUT) {
++		inode->i_flags |= S_OPAQUE;
++		ri->flags = cpu_to_je16(JFFS2_INO_FLAG_OPAQUE);
++	}
++
+ 	inode->i_op = &jffs2_dir_inode_operations;
+ 	inode->i_fop = &jffs2_dir_operations;
+ 
+@@ -779,6 +804,82 @@
+ 	return 0;
+ }
+ 
++static int jffs2_fallthru (struct inode *dir, struct dentry *dentry)
++{
++	struct jffs2_sb_info *c = JFFS2_SB_INFO(dir->i_sb);
++	uint32_t now;
++	int ret;
++
++	now = get_seconds();
++	ret = jffs2_do_link(c, JFFS2_INODE_INFO(dir), 0, DT_UNKNOWN,
++			    dentry->d_name.name, dentry->d_name.len, now);
++	if (ret)
++		return ret;
++
++	d_instantiate(dentry, NULL);
++	spin_lock(&dentry->d_lock);
++	dentry->d_flags |= DCACHE_FALLTHRU;
++	spin_unlock(&dentry->d_lock);
++
++	return 0;
++}
++
++static int jffs2_whiteout (struct inode *dir, struct dentry *old_dentry,
++			   struct dentry *new_dentry)
++{
++	struct jffs2_sb_info *c = JFFS2_SB_INFO(dir->i_sb);
++	struct jffs2_inode_info *victim_f = NULL;
++	uint32_t now;
++	int ret;
++
++	/* If it's a directory, then check whether it is really empty
++	 */
++	if (new_dentry->d_inode) {
++		victim_f = JFFS2_INODE_INFO(old_dentry->d_inode);
++		if (S_ISDIR(old_dentry->d_inode->i_mode)) {
++			struct jffs2_full_dirent *fd;
++
++			mutex_lock(&victim_f->sem);
++			for (fd = victim_f->dents; fd; fd = fd->next) {
++				if (fd->ino) {
++					mutex_unlock(&victim_f->sem);
++					return -ENOTEMPTY;
++				}
++			}
++			mutex_unlock(&victim_f->sem);
++		}
++	}
++
++	now = get_seconds();
++	ret = jffs2_do_link(c, JFFS2_INODE_INFO(dir), 0, DT_WHT,
++			    new_dentry->d_name.name, new_dentry->d_name.len, now);
++	if (ret)
++		return ret;
++
++	spin_lock(&new_dentry->d_lock);
++	new_dentry->d_flags &= ~DCACHE_FALLTHRU;
++	new_dentry->d_flags |= DCACHE_WHITEOUT;
++	spin_unlock(&new_dentry->d_lock);
++	d_add(new_dentry, NULL);
++
++	if (victim_f) {
++		/* There was a victim. Kill it off nicely */
++		drop_nlink(old_dentry->d_inode);
++		/* Don't oops if the victim was a dirent pointing to an
++		   inode which didn't exist. */
++		if (victim_f->inocache) {
++			mutex_lock(&victim_f->sem);
++			if (S_ISDIR(old_dentry->d_inode->i_mode))
++				victim_f->inocache->pino_nlink = 0;
++			else
++				victim_f->inocache->pino_nlink--;
++			mutex_unlock(&victim_f->sem);
++		}
++	}
++
++	return 0;
++}
++
+ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
+ 			 struct inode *new_dir_i, struct dentry *new_dentry)
+ {
+--- a/fs/jffs2/fs.c
++++ b/fs/jffs2/fs.c
+@@ -301,6 +301,10 @@
+ 
+ 		inode->i_op = &jffs2_dir_inode_operations;
+ 		inode->i_fop = &jffs2_dir_operations;
++
++		if (je16_to_cpu(latest_node.flags) & JFFS2_INO_FLAG_OPAQUE)
++			inode->i_flags |= S_OPAQUE;
++
+ 		break;
+ 	}
+ 	case S_IFREG:
+--- a/fs/jffs2/super.c
++++ b/fs/jffs2/super.c
+@@ -172,7 +172,7 @@
+ 
+ 	sb->s_op = &jffs2_super_operations;
+ 	sb->s_export_op = &jffs2_export_ops;
+-	sb->s_flags = sb->s_flags | MS_NOATIME;
++	sb->s_flags = sb->s_flags | MS_NOATIME | MS_WHITEOUT;
+ 	sb->s_xattr = jffs2_xattr_handlers;
+ #ifdef CONFIG_JFFS2_FS_POSIX_ACL
+ 	sb->s_flags |= MS_POSIXACL;
+--- a/include/linux/jffs2.h
++++ b/include/linux/jffs2.h
+@@ -87,6 +87,8 @@
+ #define JFFS2_INO_FLAG_USERCOMPR  2	/* User has requested a specific
+ 					   compression type */
+ 
++#define JFFS2_INO_FLAG_OPAQUE     4	/* Directory is opaque (for union mounts) */
++
+ 
+ /* These can go once we've made sure we've caught all uses without
+    byteswapping */