UBI: introduce atomic LEB change ioctl

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=866136827b9a71c39dcb06d23ce523f719eab74b
Commit:     866136827b9a71c39dcb06d23ce523f719eab74b
Parent:     60c031531a85b3580f66c2530f9b2802adcad4df
Author:     Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
AuthorDate: Thu Jan 24 16:15:14 2008 +0200
Committer:  Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
CommitDate: Fri Jan 25 16:41:25 2008 +0200

    UBI: introduce atomic LEB change ioctl
    
    We have to be able to change individual LEBs for utilities like
    ubifsck, ubifstune. For example, ubifsck has to be able to fix
    errors on the media, ubifstune has to be able to change the
    the superblock, hence this ioctl.
    
    Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
---
 include/linux/mtd/ubi.h |   17 ---------------
 include/mtd/ubi-user.h  |   51 +++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h
index c4abe03..f71201d 100644
--- a/include/linux/mtd/ubi.h
+++ b/include/linux/mtd/ubi.h
@@ -26,23 +26,6 @@
 #include <mtd/ubi-user.h>
 
 /*
- * UBI data type hint constants.
- *
- * UBI_LONGTERM: long-term data
- * UBI_SHORTTERM: short-term data
- * UBI_UNKNOWN: data persistence is unknown
- *
- * These constants are used when data is written to UBI volumes in order to
- * help the UBI wear-leveling unit to find more appropriate physical
- * eraseblocks.
- */
-enum {
-	UBI_LONGTERM = 1,
-	UBI_SHORTTERM,
-	UBI_UNKNOWN
-};
-
-/*
  * enum ubi_open_mode - UBI volume open mode constants.
  *
  * UBI_READONLY: read-only mode
diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h
index 4d184a7..a7421f1 100644
--- a/include/mtd/ubi-user.h
+++ b/include/mtd/ubi-user.h
@@ -63,7 +63,7 @@
  *
  * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
  * corresponding UBI volume character device. A pointer to a 64-bit update
- * size should be passed to the IOCTL. After then, UBI expects user to write
+ * size should be passed to the IOCTL. After this, UBI expects user to write
  * this number of bytes to the volume character device. The update is finished
  * when the claimed number of bytes is passed. So, the volume update sequence
  * is something like:
@@ -72,6 +72,15 @@
  * ioctl(fd, UBI_IOCVOLUP, &image_size);
  * write(fd, buf, image_size);
  * close(fd);
+ *
+ * Atomic eraseblock change
+ * ~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL
+ * command of the corresponding UBI volume character device. A pointer to
+ * &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is
+ * expected to write the requested amount of bytes. This is similar to the
+ * "volume update" IOCTL.
  */
 
 /*
@@ -113,11 +122,30 @@
 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
 /* An eraseblock erasure command, used for debugging, disabled by default */
 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
+/* An atomic eraseblock change command */
+#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)
 
 /* Maximum MTD device name length supported by UBI */
 #define MAX_UBI_MTD_NAME_LEN 127
 
 /*
+ * UBI data type hint constants.
+ *
+ * UBI_LONGTERM: long-term data
+ * UBI_SHORTTERM: short-term data
+ * UBI_UNKNOWN: data persistence is unknown
+ *
+ * These constants are used when data is written to UBI volumes in order to
+ * help the UBI wear-leveling unit to find more appropriate physical
+ * eraseblocks.
+ */
+enum {
+	UBI_LONGTERM  = 1,
+	UBI_SHORTTERM = 2,
+	UBI_UNKNOWN   = 3,
+};
+
+/*
  * UBI volume type constants.
  *
  * @UBI_DYNAMIC_VOLUME: dynamic volume
@@ -125,7 +153,7 @@
  */
 enum {
 	UBI_DYNAMIC_VOLUME = 3,
-	UBI_STATIC_VOLUME = 4,
+	UBI_STATIC_VOLUME  = 4,
 };
 
 /**
@@ -137,7 +165,7 @@ enum {
  *
  * This data structure is used to specify MTD device UBI has to attach and the
  * parameters it has to use. The number which should be assigned to the new UBI
- * device is passed in @ubi_num. UBI may automatically assing the number if
+ * device is passed in @ubi_num. UBI may automatically assign the number if
  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
  * @ubi_num.
  *
@@ -176,7 +204,7 @@ struct ubi_attach_req {
  * @padding2: reserved for future, not used, has to be zeroed
  * @name: volume name
  *
- * This structure is used by userspace programs when creating new volumes. The
+ * This structure is used by user-space programs when creating new volumes. The
  * @used_bytes field is only necessary when creating static volumes.
  *
  * The @alignment field specifies the required alignment of the volume logical
@@ -222,4 +250,19 @@ struct ubi_rsvol_req {
 	int32_t vol_id;
 } __attribute__ ((packed));
 
+/**
+ * struct ubi_leb_change_req - a data structure used in atomic logical
+ *                             eraseblock change requests.
+ * @lnum: logical eraseblock number to change
+ * @bytes: how many bytes will be written to the logical eraseblock
+ * @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
+ * @padding: reserved for future, not used, has to be zeroed
+ */
+struct ubi_leb_change_req {
+	int32_t lnum;
+	int32_t bytes;
+	uint8_t dtype;
+	uint8_t padding[7];
+} __attribute__ ((packed));
+
 #endif /* __UBI_USER_H__ */