From f40ac9cdf6991287f19bdafe9b0752ee40137908 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Sun, 13 Jul 2008 21:47:47 +0300 Subject: UBI: implement multiple volumes rename Quite useful ioctl which allows to make atomic system upgrades. The idea belongs to Richard Titmuss Signed-off-by: Artem Bityutskiy --- include/mtd/ubi-user.h | 60 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 57 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h index a7421f130cc0..e8e57c3dfcdb 100644 --- a/include/mtd/ubi-user.h +++ b/include/mtd/ubi-user.h @@ -58,6 +58,13 @@ * device should be used. A &struct ubi_rsvol_req object has to be properly * filled and a pointer to it has to be passed to the IOCTL. * + * UBI volumes re-name + * ~~~~~~~~~~~~~~~~~~~ + * + * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command + * of the UBI character device should be used. A &struct ubi_rnvol_req object + * has to be properly filled and a pointer to it has to be passed to the IOCTL. + * * UBI volume update * ~~~~~~~~~~~~~~~~~ * @@ -104,6 +111,8 @@ #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t) /* Re-size an UBI volume */ #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req) +/* Re-name volumes */ +#define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req) /* IOCTL commands of the UBI control character device */ @@ -128,6 +137,9 @@ /* Maximum MTD device name length supported by UBI */ #define MAX_UBI_MTD_NAME_LEN 127 +/* Maximum amount of UBI volumes that can be re-named at one go */ +#define UBI_MAX_RNVOL 32 + /* * UBI data type hint constants. * @@ -189,7 +201,7 @@ struct ubi_attach_req { int32_t ubi_num; int32_t mtd_num; int32_t vid_hdr_offset; - uint8_t padding[12]; + int8_t padding[12]; }; /** @@ -250,6 +262,48 @@ struct ubi_rsvol_req { int32_t vol_id; } __attribute__ ((packed)); +/** + * struct ubi_rnvol_req - volumes re-name request. + * @count: count of volumes to re-name + * @padding1: reserved for future, not used, has to be zeroed + * @vol_id: ID of the volume to re-name + * @name_len: name length + * @padding2: reserved for future, not used, has to be zeroed + * @name: new volume name + * + * UBI allows to re-name up to %32 volumes at one go. The count of volumes to + * re-name is specified in the @count field. The ID of the volumes to re-name + * and the new names are specified in the @vol_id and @name fields. + * + * The UBI volume re-name operation is atomic, which means that should power cut + * happen, the volumes will have either old name or new name. So the possible + * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes + * A and B one may create temporary volumes %A1 and %B1 with the new contents, + * then atomically re-name A1->A and B1->B, in which case old %A and %B will + * be removed. + * + * If it is not desirable to remove old A and B, the re-name request has to + * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1 + * become A and B, and old A and B will become A1 and B1. + * + * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1 + * and B1 become A and B, and old A and B become X and Y. + * + * In other words, in case of re-naming into an existing volume name, the + * existing volume is removed, unless it is re-named as well at the same + * re-name request. + */ +struct ubi_rnvol_req { + int32_t count; + int8_t padding1[12]; + struct { + int32_t vol_id; + int16_t name_len; + int8_t padding2[2]; + char name[UBI_MAX_VOLUME_NAME + 1]; + } ents[UBI_MAX_RNVOL]; +} __attribute__ ((packed)); + /** * struct ubi_leb_change_req - a data structure used in atomic logical * eraseblock change requests. @@ -261,8 +315,8 @@ struct ubi_rsvol_req { struct ubi_leb_change_req { int32_t lnum; int32_t bytes; - uint8_t dtype; - uint8_t padding[7]; + int8_t dtype; + int8_t padding[7]; } __attribute__ ((packed)); #endif /* __UBI_USER_H__ */ -- cgit v1.2.2