JFFS2: add UBI support

This patch make JFFS2 able to work with UBI volumes via the emulated MTD
devices which are directly mapped to these volumes.
Signed-off-by: NArtem Bityutskiy <dedekind@infradead.org>

fs/jffs2/fs.c

@@ -672,6 +672,13 @@ static int jffs2_flash_setup(struct jffs2_sb_info *c) {
 			return ret;
 	}
 
+	/* and an UBI volume */
+	if (jffs2_ubivol(c)) {
+		ret = jffs2_ubivol_setup(c);
+		if (ret)
+			return ret;
+	}
+
 	return ret;
 }
 
@@ -690,4 +697,9 @@ void jffs2_flash_cleanup(struct jffs2_sb_info *c) {
 	if (jffs2_nor_wbuf_flash(c)) {
 		jffs2_nor_wbuf_flash_cleanup(c);
 	}
+
+	/* and an UBI volume */
+	if (jffs2_ubivol(c)) {
+		jffs2_ubivol_cleanup(c);
+	}
 }

fs/jffs2/os-linux.h

@@ -98,6 +98,9 @@ static inline void jffs2_init_inode_info(struct jffs2_inode_info *f)
 #define jffs2_nor_wbuf_flash(c) (0)
 #define jffs2_nor_wbuf_flash_setup(c) (0)
 #define jffs2_nor_wbuf_flash_cleanup(c) do {} while (0)
+#define jffs2_ubivol(c) (0)
+#define jffs2_ubivol_setup(c) (0)
+#define jffs2_ubivol_cleanup(c) do {} while (0)
 
 #else /* NAND and/or ECC'd NOR support present */
 
@@ -133,6 +136,9 @@ void jffs2_nand_flash_cleanup(struct jffs2_sb_info *c);
 #define jffs2_dataflash(c) (c->mtd->type == MTD_DATAFLASH)
 int jffs2_dataflash_setup(struct jffs2_sb_info *c);
 void jffs2_dataflash_cleanup(struct jffs2_sb_info *c);
+#define jffs2_ubivol(c) (c->mtd->type == MTD_UBIVOLUME)
+int jffs2_ubivol_setup(struct jffs2_sb_info *c);
+void jffs2_ubivol_cleanup(struct jffs2_sb_info *c);
 
 #define jffs2_nor_wbuf_flash(c) (c->mtd->type == MTD_NORFLASH && ! (c->mtd->flags & MTD_BIT_WRITEABLE))
 int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c);

fs/jffs2/wbuf.c

@@ -1208,3 +1208,27 @@ int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c) {
 void jffs2_nor_wbuf_flash_cleanup(struct jffs2_sb_info *c) {
 	kfree(c->wbuf);
 }
+
+int jffs2_ubivol_setup(struct jffs2_sb_info *c) {
+	c->cleanmarker_size = 0;
+
+	if (c->mtd->writesize == 1)
+		/* We do not need write-buffer */
+		return 0;
+
+	init_rwsem(&c->wbuf_sem);
+
+	c->wbuf_pagesize =  c->mtd->writesize;
+	c->wbuf_ofs = 0xFFFFFFFF;
+	c->wbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+	if (!c->wbuf)
+		return -ENOMEM;
+
+	printk(KERN_INFO "JFFS2 write-buffering enabled buffer (%d) erasesize (%d)\n", c->wbuf_pagesize, c->sector_size);
+
+	return 0;
+}
+
+void jffs2_ubivol_cleanup(struct jffs2_sb_info *c) {
+	kfree(c->wbuf);
+}