Re: validate_sb: bad superblock, error 8 (Minimum UBI volume size for UBIFS image)

[Artem Bityutskiy <dedekind1@gmail.com>]

On Sat, 2011-01-15 at 10:48 +0000, Andrew Murray wrote:
> On 11 January 2011 09:47, Andrew Murray <amurray@mpcdata.com> wrote:
> >
> > Is there a way to determine the minimum UBI volume size which will
> > support a given UBIFS filesystem image?
> >
> 
> My conclusion is this (with my version of kernel and mkfs.ubifs tool):
> 
> (Min No. UBI Volume LEBS) = (jrn_lebs) + 3 + (log lebs) + (lpt_lebs) +
> (orph_lebs)
> 
> And these values can all be determined (or specified) by the
> mkfs.ubifs tool by using the verbose -v flag.
> 
> This seems to hold true - Does this seem reasonable?

These are definitions for ubifs-media.h kernel header file, and the
absolute minimum is UBIFS_MIN_LEB_CNT.

/*
 * The below constants define the absolute minimum values for various UBIFS
 * media areas. Many of them actually depend of flash geometry and the FS
 * configuration (number of journal heads, orphan LEBs, etc). This means that
 * the smallest volume size which can be used for UBIFS cannot be pre-defined
 * by these constants. The file-system that meets the below limitation will not
 * necessarily mount. UBIFS does run-time calculations and validates the FS
 * size.
 */

/* Minimum number of logical eraseblocks in the log */
#define UBIFS_MIN_LOG_LEBS 2
/* Minimum number of bud logical eraseblocks (one for each head) */
#define UBIFS_MIN_BUD_LEBS 3
/* Minimum number of journal logical eraseblocks */
#define UBIFS_MIN_JNL_LEBS (UBIFS_MIN_LOG_LEBS + UBIFS_MIN_BUD_LEBS)
/* Minimum number of LPT area logical eraseblocks */
#define UBIFS_MIN_LPT_LEBS 2
/* Minimum number of orphan area logical eraseblocks */
#define UBIFS_MIN_ORPH_LEBS 1
/*
 * Minimum number of main area logical eraseblocks (buds, 3 for the index, 1
 * for GC, 1 for deletions, and at least 1 for committed data).
 */
#define UBIFS_MIN_MAIN_LEBS (UBIFS_MIN_BUD_LEBS + 6)

/* Minimum number of logical eraseblocks */
#define UBIFS_MIN_LEB_CNT (UBIFS_SB_LEBS + UBIFS_MST_LEBS + \
                           UBIFS_MIN_LOG_LEBS + UBIFS_MIN_LPT_LEBS + \
                           UBIFS_MIN_ORPH_LEBS + UBIFS_MIN_MAIN_LEBS)
-- 
Best Regards,
Artem Bityutskiy (Битюцкий Артём)