openwrt/target/linux/generic/patches-3.8/400-rootfs_split.patch

--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -23,6 +23,14 @@ config MTD_TESTS
 	  WARNING: some of the tests will ERASE entire MTD device which they
 	  test. Do not use these tests unless you really know what you do.
 
+config MTD_ROOTFS_ROOT_DEV
+	bool "Automatically set 'rootfs' partition to be root filesystem"
+	default y
+
+config MTD_ROOTFS_SPLIT
+	bool "Automatically split 'rootfs' partition for squashfs"
+	default y
+
 config MTD_REDBOOT_PARTS
 	tristate "RedBoot partition table parsing"
 	---help---
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -29,6 +29,8 @@
 #include <linux/kmod.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
+#include <linux/root_dev.h>
+#include <linux/magic.h>
 #include <linux/err.h>
 
 #include "mtdcore.h"
@@ -50,7 +52,7 @@ struct mtd_part {
  * the pointer to that structure with this macro.
  */
 #define PART(x)  ((struct mtd_part *)(x))
-
+#define IS_PART(mtd) (mtd->_read == part_read)
 
 /*
  * MTD methods which simply translate the effective address and pass through
@@ -613,6 +615,155 @@ int mtd_del_partition(struct mtd_info *m
 }
 EXPORT_SYMBOL_GPL(mtd_del_partition);
 
+#ifdef CONFIG_MTD_ROOTFS_SPLIT
+#define ROOTFS_SPLIT_NAME "rootfs_data"
+#define ROOTFS_REMOVED_NAME "<removed>"
+
+struct squashfs_super_block {
+	__le32 s_magic;
+	__le32 pad0[9];
+	__le64 bytes_used;
+};
+
+
+static int split_squashfs(struct mtd_info *master, int offset, int *split_offset)
+{
+	struct squashfs_super_block sb;
+	int len, ret;
+
+	ret = mtd_read(master, offset, sizeof(sb), &len, (void *) &sb);
+	if (ret || (len != sizeof(sb))) {
+		printk(KERN_ALERT "split_squashfs: error occured while reading "
+			"from \"%s\"\n", master->name);
+		return -EINVAL;
+	}
+
+	if (SQUASHFS_MAGIC != le32_to_cpu(sb.s_magic) ) {
+		printk(KERN_ALERT "split_squashfs: no squashfs found in \"%s\"\n",
+			master->name);
+		*split_offset = 0;
+		return 0;
+	}
+
+	if (le64_to_cpu((sb.bytes_used)) <= 0) {
+		printk(KERN_ALERT "split_squashfs: squashfs is empty in \"%s\"\n",
+			master->name);
+		*split_offset = 0;
+		return 0;
+	}
+
+	len = (u32) le64_to_cpu(sb.bytes_used);
+	len += (offset & 0x000fffff);
+	len +=  (master->erasesize - 1);
+	len &= ~(master->erasesize - 1);
+	len -= (offset & 0x000fffff);
+	*split_offset = offset + len;
+
+	return 0;
+}
+
+static int split_rootfs_data(struct mtd_info *master, struct mtd_info *rpart, const struct mtd_partition *part)
+{
+	struct mtd_partition *dpart;
+	struct mtd_part *slave = NULL;
+	struct mtd_part *spart;
+	int ret, split_offset = 0;
+
+	spart = PART(rpart);
+	ret = split_squashfs(master, spart->offset, &split_offset);
+	if (ret)
+		return ret;
+
+	if (split_offset <= 0)
+		return 0;
+
+	dpart = kmalloc(sizeof(*part)+sizeof(ROOTFS_SPLIT_NAME)+1, GFP_KERNEL);
+	if (dpart == NULL) {
+		printk(KERN_INFO "split_squashfs: no memory for partition \"%s\"\n",
+			ROOTFS_SPLIT_NAME);
+		return -ENOMEM;
+	}
+
+	memcpy(dpart, part, sizeof(*part));
+	dpart->name = (unsigned char *)&dpart[1];
+	strcpy(dpart->name, ROOTFS_SPLIT_NAME);
+
+	dpart->size = rpart->size - (split_offset - spart->offset);
+	dpart->offset = split_offset;
+
+	if (dpart == NULL)
+		return 1;
+
+	printk(KERN_INFO "mtd: partition \"%s\" created automatically, ofs=%llX, len=%llX \n",
+		ROOTFS_SPLIT_NAME, dpart->offset, dpart->size);
+
+	slave = allocate_partition(master, dpart, 0, split_offset);
+	if (IS_ERR(slave))
+		return PTR_ERR(slave);
+	mutex_lock(&mtd_partitions_mutex);
+	list_add(&slave->list, &mtd_partitions);
+	mutex_unlock(&mtd_partitions_mutex);
+
+	add_mtd_device(&slave->mtd);
+
+	rpart->split = &slave->mtd;
+
+	return 0;
+}
+
+static int refresh_rootfs_split(struct mtd_info *mtd)
+{
+	struct mtd_partition tpart;
+	struct mtd_part *part;
+	char *name;
+	//int index = 0;
+	int offset, size;
+	int ret;
+
+	part = PART(mtd);
+
+	/* check for the new squashfs offset first */
+	ret = split_squashfs(part->master, part->offset, &offset);
+	if (ret)
+		return ret;
+
+	if ((offset > 0) && !mtd->split) {
+		printk(KERN_INFO "%s: creating new split partition for \"%s\"\n", __func__, mtd->name);
+		/* if we don't have a rootfs split partition, create a new one */
+		tpart.name = (char *) mtd->name;
+		tpart.size = mtd->size;
+		tpart.offset = part->offset;
+
+		return split_rootfs_data(part->master, &part->mtd, &tpart);
+	} else if ((offset > 0) && mtd->split) {
+		/* update the offsets of the existing partition */
+		size = mtd->size + part->offset - offset;
+
+		part = PART(mtd->split);
+		part->offset = offset;
+		part->mtd.size = size;
+		printk(KERN_INFO "%s: %s partition \"" ROOTFS_SPLIT_NAME "\", offset: 0x%06x (0x%06x)\n",
+			__func__, (!strcmp(part->mtd.name, ROOTFS_SPLIT_NAME) ? "updating" : "creating"),
+			(u32) part->offset, (u32) part->mtd.size);
+		name = kmalloc(sizeof(ROOTFS_SPLIT_NAME) + 1, GFP_KERNEL);
+		strcpy(name, ROOTFS_SPLIT_NAME);
+		part->mtd.name = name;
+	} else if ((offset <= 0) && mtd->split) {
+		printk(KERN_INFO "%s: removing partition \"%s\"\n", __func__, mtd->split->name);
+
+		/* mark existing partition as removed */
+		part = PART(mtd->split);
+		name = kmalloc(sizeof(ROOTFS_SPLIT_NAME) + 1, GFP_KERNEL);
+		strcpy(name, ROOTFS_REMOVED_NAME);
+		part->mtd.name = name;
+		part->offset = 0;
+		part->mtd.size = 0;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_MTD_ROOTFS_SPLIT */
+
 /*
  * This function, given a master MTD object and a partition table, creates
  * and registers slave MTD objects which are bound to the master according to
@@ -629,6 +780,9 @@ int add_mtd_partitions(struct mtd_info *
 	struct mtd_part *slave;
 	uint64_t cur_offset = 0;
 	int i;
+#ifdef CONFIG_MTD_ROOTFS_SPLIT
+	int ret;
+#endif
 
 	printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
 
@@ -643,12 +797,53 @@ int add_mtd_partitions(struct mtd_info *
 
 		add_mtd_device(&slave->mtd);
 
+		if (!strcmp(parts[i].name, "rootfs")) {
+#ifdef CONFIG_MTD_ROOTFS_ROOT_DEV
+			if (ROOT_DEV == 0) {
+				printk(KERN_NOTICE "mtd: partition \"rootfs\" "
+					"set to be root filesystem\n");
+				ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, slave->mtd.index);
+			}
+#endif
+#ifdef CONFIG_MTD_ROOTFS_SPLIT
+			ret = split_rootfs_data(master, &slave->mtd, &parts[i]);
+			/* if (ret == 0)
+			 * 	j++; */
+#endif
+		}
+
 		cur_offset = slave->offset + slave->mtd.size;
 	}
 
 	return 0;
 }
 
+int mtd_device_refresh(struct mtd_info *mtd)
+{
+	int ret = 0;
+
+	if (IS_PART(mtd)) {
+		struct mtd_part *part;
+		struct mtd_info *master;
+
+		part = PART(mtd);
+		master = part->master;
+		if (master->refresh_device)
+			ret = master->refresh_device(master);
+	}
+
+	if (!ret && mtd->refresh_device)
+		ret = mtd->refresh_device(mtd);
+
+#ifdef CONFIG_MTD_ROOTFS_SPLIT
+	if (!ret && IS_PART(mtd) && !strcmp(mtd->name, "rootfs"))
+		refresh_rootfs_split(mtd);
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtd_device_refresh);
+
 static DEFINE_SPINLOCK(part_parser_lock);
 static LIST_HEAD(part_parsers);
 
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -1012,6 +1012,12 @@ static int mtdchar_ioctl(struct file *fi
 		break;
 	}
 
+	case MTDREFRESH:
+	{
+		ret = mtd_device_refresh(mtd);
+		break;
+	}
+
 	default:
 		ret = -ENOTTY;
 	}
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -114,6 +114,7 @@ struct nand_ecclayout {
 
 struct module;	/* only needed for owner field in mtd_info */
 
+struct mtd_info;
 struct mtd_info {
 	u_char type;
 	uint32_t flags;
@@ -226,6 +227,9 @@ struct mtd_info {
 	int (*_block_markbad) (struct mtd_info *mtd, loff_t ofs);
 	int (*_suspend) (struct mtd_info *mtd);
 	void (*_resume) (struct mtd_info *mtd);
+	int (*refresh_device)(struct mtd_info *mtd);
+	struct mtd_info *split;
+
 	/*
 	 * If the driver is something smart, like UBI, it may need to maintain
 	 * its own reference counting. The below functions are only for driver.
@@ -368,6 +372,7 @@ extern int mtd_device_parse_register(str
 			      int defnr_parts);
 #define mtd_device_register(master, parts, nr_parts)	\
 	mtd_device_parse_register(master, NULL, NULL, parts, nr_parts)
+extern int mtd_device_refresh(struct mtd_info *master);
 extern int mtd_device_unregister(struct mtd_info *master);
 extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
 extern int __get_mtd_device(struct mtd_info *mtd);
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -36,12 +36,14 @@
  * erasesize aligned (e.g. use MTDPART_OFS_NEXTBLK).
  */
 
+struct mtd_partition;
 struct mtd_partition {
 	char *name;			/* identifier string */
 	uint64_t size;			/* partition size */
 	uint64_t offset;		/* offset within the master MTD space */
 	uint32_t mask_flags;		/* master MTD flags to mask out for this partition */
 	struct nand_ecclayout *ecclayout;	/* out of band layout for this partition (NAND only) */
+	int (*refresh_partition)(struct mtd_info *);
 };
 
 #define MTDPART_OFS_RETAIN	(-3)
--- a/include/uapi/mtd/mtd-abi.h
+++ b/include/uapi/mtd/mtd-abi.h
@@ -202,6 +202,7 @@ struct otp_info {
  * without OOB, e.g., NOR flash.
  */
 #define MEMWRITE		_IOWR('M', 24, struct mtd_write_req)
+#define MTDREFRESH		_IO('M', 50)
 
 /*
  * Obsolete legacy interface. Keep it in order not to break userspace