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UBI: implement multiple volumes rename

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Quite useful ioctl which allows to make atomic system upgrades.
The idea belongs to Richard Titmuss <richard_titmuss@logitech.com>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Artem Bityutskiy
2008-07-13 21:47:47 +03:00
parent c8566350a3
commit f40ac9cdf6
6 changed files with 375 additions and 15 deletions
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60
include/mtd/ubi-user.h
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@@ -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__ */