diff options
Diffstat (limited to 'fs/yaffs2/yaffs_packedtags2.c')
| -rw-r--r-- | fs/yaffs2/yaffs_packedtags2.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/fs/yaffs2/yaffs_packedtags2.c b/fs/yaffs2/yaffs_packedtags2.c new file mode 100644 index 000000000000..8e7fea3d2860 --- /dev/null +++ b/fs/yaffs2/yaffs_packedtags2.c @@ -0,0 +1,196 @@ +/* + * YAFFS: Yet Another Flash File System. A NAND-flash specific file system. + * + * Copyright (C) 2002-2010 Aleph One Ltd. + * for Toby Churchill Ltd and Brightstar Engineering + * + * Created by Charles Manning <charles@aleph1.co.uk> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "yaffs_packedtags2.h" +#include "yportenv.h" +#include "yaffs_trace.h" +#include "yaffs_tagsvalidity.h" + +/* This code packs a set of extended tags into a binary structure for + * NAND storage + */ + +/* Some of the information is "extra" struff which can be packed in to + * speed scanning + * This is defined by having the EXTRA_HEADER_INFO_FLAG set. + */ + +/* Extra flags applied to chunk_id */ + +#define EXTRA_HEADER_INFO_FLAG 0x80000000 +#define EXTRA_SHRINK_FLAG 0x40000000 +#define EXTRA_SHADOWS_FLAG 0x20000000 +#define EXTRA_SPARE_FLAGS 0x10000000 + +#define ALL_EXTRA_FLAGS 0xF0000000 + +/* Also, the top 4 bits of the object Id are set to the object type. */ +#define EXTRA_OBJECT_TYPE_SHIFT (28) +#define EXTRA_OBJECT_TYPE_MASK ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT) + +static void yaffs_dump_packed_tags2_tags_only(const struct + yaffs_packed_tags2_tags_only *ptt) +{ + yaffs_trace(YAFFS_TRACE_MTD, + "packed tags obj %d chunk %d byte %d seq %d", + ptt->obj_id, ptt->chunk_id, ptt->n_bytes, ptt->seq_number); +} + +static void yaffs_dump_packed_tags2(const struct yaffs_packed_tags2 *pt) +{ + yaffs_dump_packed_tags2_tags_only(&pt->t); +} + +static void yaffs_dump_tags2(const struct yaffs_ext_tags *t) +{ + yaffs_trace(YAFFS_TRACE_MTD, + "ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte %d del %d ser %d seq %d", + t->ecc_result, t->block_bad, t->chunk_used, t->obj_id, + t->chunk_id, t->n_bytes, t->is_deleted, t->serial_number, + t->seq_number); + +} + +void yaffs_pack_tags2_tags_only(struct yaffs_packed_tags2_tags_only *ptt, + const struct yaffs_ext_tags *t) +{ + ptt->chunk_id = t->chunk_id; + ptt->seq_number = t->seq_number; + ptt->n_bytes = t->n_bytes; + ptt->obj_id = t->obj_id; + + if (t->chunk_id == 0 && t->extra_available) { + /* Store the extra header info instead */ + /* We save the parent object in the chunk_id */ + ptt->chunk_id = EXTRA_HEADER_INFO_FLAG | t->extra_parent_id; + if (t->extra_is_shrink) + ptt->chunk_id |= EXTRA_SHRINK_FLAG; + if (t->extra_shadows) + ptt->chunk_id |= EXTRA_SHADOWS_FLAG; + + ptt->obj_id &= ~EXTRA_OBJECT_TYPE_MASK; + ptt->obj_id |= (t->extra_obj_type << EXTRA_OBJECT_TYPE_SHIFT); + + if (t->extra_obj_type == YAFFS_OBJECT_TYPE_HARDLINK) + ptt->n_bytes = t->extra_equiv_id; + else if (t->extra_obj_type == YAFFS_OBJECT_TYPE_FILE) + ptt->n_bytes = t->extra_length; + else + ptt->n_bytes = 0; + } + + yaffs_dump_packed_tags2_tags_only(ptt); + yaffs_dump_tags2(t); +} + +void yaffs_pack_tags2(struct yaffs_packed_tags2 *pt, + const struct yaffs_ext_tags *t, int tags_ecc) +{ + yaffs_pack_tags2_tags_only(&pt->t, t); + + if (tags_ecc) + yaffs_ecc_calc_other((unsigned char *)&pt->t, + sizeof(struct + yaffs_packed_tags2_tags_only), + &pt->ecc); +} + +void yaffs_unpack_tags2_tags_only(struct yaffs_ext_tags *t, + struct yaffs_packed_tags2_tags_only *ptt) +{ + + memset(t, 0, sizeof(struct yaffs_ext_tags)); + + yaffs_init_tags(t); + + if (ptt->seq_number != 0xFFFFFFFF) { + t->block_bad = 0; + t->chunk_used = 1; + t->obj_id = ptt->obj_id; + t->chunk_id = ptt->chunk_id; + t->n_bytes = ptt->n_bytes; + t->is_deleted = 0; + t->serial_number = 0; + t->seq_number = ptt->seq_number; + + /* Do extra header info stuff */ + + if (ptt->chunk_id & EXTRA_HEADER_INFO_FLAG) { + t->chunk_id = 0; + t->n_bytes = 0; + + t->extra_available = 1; + t->extra_parent_id = + ptt->chunk_id & (~(ALL_EXTRA_FLAGS)); + t->extra_is_shrink = + (ptt->chunk_id & EXTRA_SHRINK_FLAG) ? 1 : 0; + t->extra_shadows = + (ptt->chunk_id & EXTRA_SHADOWS_FLAG) ? 1 : 0; + t->extra_obj_type = + ptt->obj_id >> EXTRA_OBJECT_TYPE_SHIFT; + t->obj_id &= ~EXTRA_OBJECT_TYPE_MASK; + + if (t->extra_obj_type == YAFFS_OBJECT_TYPE_HARDLINK) + t->extra_equiv_id = ptt->n_bytes; + else + t->extra_length = ptt->n_bytes; + } + } + + yaffs_dump_packed_tags2_tags_only(ptt); + yaffs_dump_tags2(t); + +} + +void yaffs_unpack_tags2(struct yaffs_ext_tags *t, struct yaffs_packed_tags2 *pt, + int tags_ecc) +{ + + enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_NO_ERROR; + + if (pt->t.seq_number != 0xFFFFFFFF && tags_ecc) { + /* Chunk is in use and we need to do ECC */ + + struct yaffs_ecc_other ecc; + int result; + yaffs_ecc_calc_other((unsigned char *)&pt->t, + sizeof(struct + yaffs_packed_tags2_tags_only), + &ecc); + result = + yaffs_ecc_correct_other((unsigned char *)&pt->t, + sizeof(struct + yaffs_packed_tags2_tags_only), + &pt->ecc, &ecc); + switch (result) { + case 0: + ecc_result = YAFFS_ECC_RESULT_NO_ERROR; + break; + case 1: + ecc_result = YAFFS_ECC_RESULT_FIXED; + break; + case -1: + ecc_result = YAFFS_ECC_RESULT_UNFIXED; + break; + default: + ecc_result = YAFFS_ECC_RESULT_UNKNOWN; + } + } + + yaffs_unpack_tags2_tags_only(t, &pt->t); + + t->ecc_result = ecc_result; + + yaffs_dump_packed_tags2(pt); + yaffs_dump_tags2(t); +} |