On Thursday 23 June 2011 08:05:21 Mark Whitney wrote:
> I am experiencing some data loss when writing to a partition with an old
> version of yaffs and then mounting with a new version.
>
> I have been using the 2.6.32 branch of the android omap kernel (git://
> android.git.kernel.org/kernel/omap.git), which has a version of yaffs2
> patched into it. It looks like it is based off this commit on the yaffs2
> repository master branch:
>
> commit 3a263f2d5074abcd6129dff4f1bd1a0ab45a04da
> Author: charles <charles>
> Date: Wed Sep 9 03:03:01 2009 +0000
>
> Rationalise stats gathering for nand access. Does not instrument
> mounting.
>
>
> I am now trying the same 2.6.32 kernel with relatively recent yaffs2 code
> patched in:
>
> commit 7715144e7d55b2854f907001c432348e4caa5954
> Author: Charles Manning <cdhmanning@gmail.com>
> Date: Wed Apr 13 10:20:06 2011 +1200
>
> yaffs: Handle attribute size query correctly.
>
> If getxattr() is passed a buffer size of zero then this is a size
> query. Return the size of the attribute without copying it out.
>
> Signed-off-by: Charles Manning <cdhmanning@gmail.com>
>
>
>
>
> When I remount a nand partition that I originally wrote to with the old
> yaffs2 kernel, using the new yaffs2 kernel, the partition has no data.
> Additionally, when I boot back into the old kernel again and remount the
> data is still missing:
>
> <boot old yaffs>
>
> root@homebase:~# mount -t yaffs2 /dev/mtdblock5 /mnt/card/
> yaffs: dev is 32505861 name is "mtdblock5"
> yaffs: passed flags ""
> yaffs: Attempting MTD mount on 31.5, "mtdblock5"
> yaffs_read_super: isCheckpointed 0
> root@homebase:~# ls -l /mnt/card/
> drw-rw-rw- 1 root root 2048 Jun 22 19:34 lost+found
> root@homebase:~# cat /dev/urandom > /mnt/card/testdata
> ^C
> root@homebase:~# cat /proc/yaffs
> YAFFS built:May 26 2011 16:35:02
> $Id$
> $Id$
>
> Device 0 "system_a"
> startBlock......... 0
> endBlock........... 785
> totalBytesPerChunk. 2048
> nDataBytesPerChunk. 2048
> chunkGroupBits..... 0
> chunkGroupSize..... 1
> nErasedBlocks...... 767
> nReservedBlocks.... 5
> blocksInCheckpoint. 0
> nTnodesCreated..... 100
> nFreeTnodes........ 13
> nObjectsCreated.... 200
> nFreeObjects....... 95
> nFreeChunks........ 49120
> nPageWrites........ 1185
> nPageReads......... 1186
> nBlockErasures..... 1
> nGCCopies.......... 0
> garbageCollections. 0
> passiveGCs......... 0
> nRetriedWrites..... 0
> nShortOpCaches..... 10
> nRetireBlocks...... 0
> eccFixed........... 0
> eccUnfixed......... 0
> tagsEccFixed....... 0
> tagsEccUnfixed..... 0
> cacheHits.......... 0
> nDeletedFiles...... 0
> nUnlinkedFiles..... 0
> nBackgroudDeletions 0
> useNANDECC......... 1
> isYaffs2........... 1
> inbandTags......... 0
>
> root@homebase:~# ls -l /mnt/card/
> drw-rw-rw- 1 root root 2048 Jun 22 19:34 lost+found
> -rw-r--r-- 1 root root 2420736 Jun 22 19:34 testdata
> root@homebase:~# umount /dev/mtdblock5
> save exit: isCheckpointed 1
> save exit: isCheckpointed 1
> root@homebase:~# sync
>
>
> <boot new yaffs>
>
> root@homebase:~# mount -t yaffs2 /dev/mtdblock5 /mnt/card/
> yaffs: dev is 32505861 name is "mtdblock5" rw
> yaffs: passed flags ""
> root@homebase:~# cat /proc/yaffs
> Multi-version YAFFS built:Jun 22 2011 15:11:04
>
>
> Device 0 "system_a"
> start_block.......... 0
> end_block............ 785
> total_bytes_per_chunk 2048
> use_nand_ecc......... 1
> no_tags_ecc.......... 0
> is_yaffs2............ 1
> inband_tags.......... 0
> empty_lost_n_found... 1
> disable_lazy_load.... 0
> refresh_period....... 500
> n_caches............. 10
> n_reserved_blocks.... 5
> always_check_erased.. 0
>
> data_bytes_per_chunk. 2048
> chunk_grp_bits....... 0
> chunk_grp_size....... 1
> n_erased_blocks...... 785
> blocks_in_checkpt.... 0
>
> n_tnodes............. 0
> n_obj................ 4
> n_free_chunks........ 50304
>
> n_page_writes........ 0
> n_page_reads......... 0
> n_erasures........... 1
> n_gc_copies.......... 0
> all_gcs.............. 1
> passive_gc_count..... 1
> oldest_dirty_gc_count 0
> n_gc_blocks.......... 0
> bg_gcs............... 0
> n_retired_writes..... 0
> n_retired_blocks..... 0
> n_ecc_fixed.......... 0
> n_ecc_unfixed........ 0
> n_tags_ecc_fixed..... 0
> n_tags_ecc_unfixed... 0
> cache_hits........... 0
> n_deleted_files...... 0
> n_unlinked_files..... 1
> refresh_count........ 1
> n_bg_deletions....... 0
> root@homebase:~# ls /mnt/card/
> lost+found
> root@homebase:~#
>
> <boot old yaffs again>
>
> root@homebase:~# mount -t yaffs2 /dev/mtdblock5 /mnt/card/
> yaffs: dev is 32505861 name is "mtdblock5"
> yaffs: passed flags ""
> yaffs: Attempting MTD mount on 31.5, "mtdblock5"
> yaffs_read_super: isCheckpointed 0
> root@homebase:~# ls -l /mnt/card/
> drw-rw-rw- 1 root root 2048 Jun 22 20:02 lost+found
> root@homebase:~# cat /proc/yaffs
> YAFFS built:May 26 2011 16:35:02
> $Id$
> $Id$
>
> Device 0 "system_a"
> startBlock......... 0
> endBlock........... 785
> totalBytesPerChunk. 2048
> nDataBytesPerChunk. 2048
> chunkGroupBits..... 0
> chunkGroupSize..... 1
> nErasedBlocks...... 785
> nReservedBlocks.... 5
> blocksInCheckpoint. 0
> nTnodesCreated..... 100
> nFreeTnodes........ 100
> nObjectsCreated.... 200
> nFreeObjects....... 96
> nFreeChunks........ 50304
> nPageWrites........ 0
> nPageReads......... 0
> nBlockErasures..... 0
> nGCCopies.......... 0
> garbageCollections. 0
> passiveGCs......... 0
> nRetriedWrites..... 0
> nShortOpCaches..... 10
> nRetireBlocks...... 0
> eccFixed........... 0
> eccUnfixed......... 0
> tagsEccFixed....... 0
> tagsEccUnfixed..... 0
> cacheHits.......... 0
> nDeletedFiles...... 0
> nUnlinkedFiles..... 1
> nBackgroudDeletions 0
> useNANDECC......... 1
> isYaffs2........... 1
> inbandTags......... 0
> root@homebase:~#
>
>
> Are there some versions in which compatibility is not guaranteed? Is there
> a compatibility mode I should be using or an upgrade utility? I also tried
> mounting under the new yaffs kernel with "-t yaffs" and got the same
> result. Any advice or guidelines for mounting the old partitions with the
> new code would be appreciated, thanks.
This is odd. These should be compatible.
-- Charles
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