From 963f0cf6d116d83c558a8efe9045c1c5ad7aed34 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Thu, 26 Mar 2009 12:51:21 +0200 Subject: UBIFS: add R/O compatibility Now UBIFS is supported by u-boot. If we ever decide to change the media format, then people will have to upgrade their u-boots to mount new format images. However, very often it is possible to preserve R/O forward-compatibility, even though the write forward-compatibility is not preserved. This patch introduces a new super-block field which stores the R/O compatibility version. Signed-off-by: Artem Bityutskiy Acked-by: Adrian Hunter --- fs/ubifs/ubifs.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/ubifs/ubifs.h') diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index a53b9a6df2be..0a8341e14088 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -934,6 +934,7 @@ struct ubifs_debug_info; * by @commit_sem * @cnt_lock: protects @highest_inum and @max_sqnum counters * @fmt_version: UBIFS on-flash format version + * @ro_compat_version: R/O compatibility version * @uuid: UUID from super block * * @lhead_lnum: log head logical eraseblock number @@ -966,6 +967,7 @@ struct ubifs_debug_info; * recovery) * @bulk_read: enable bulk-reads * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc) + * @rw_incompat: the media is not R/W compatible * * @tnc_mutex: protects the Tree Node Cache (TNC), @zroot, @cnext, @enext, and * @calc_idx_sz @@ -1179,6 +1181,7 @@ struct ubifs_info { unsigned long long cmt_no; spinlock_t cnt_lock; int fmt_version; + int ro_compat_version; unsigned char uuid[16]; int lhead_lnum; @@ -1207,6 +1210,7 @@ struct ubifs_info { unsigned int no_chk_data_crc:1; unsigned int bulk_read:1; unsigned int default_compr:2; + unsigned int rw_incompat:1; struct mutex tnc_mutex; struct ubifs_zbranch zroot; -- cgit v1.2.3