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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2009-03-26 12:51:21 +0200
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2009-03-26 16:36:20 +0200
commit963f0cf6d116d83c558a8efe9045c1c5ad7aed34 (patch)
tree43937f0d742bfac7dfc1a00bae8f72e98dc87425 /fs/ubifs/super.c
parentfcabb3479e2b15abfd2d2ef5363295f16e98b2d7 (diff)
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 <Artem.Bityutskiy@nokia.com> Acked-by: Adrian Hunter <Adrian.Hunter@nokia.com>
Diffstat (limited to 'fs/ubifs/super.c')
-rw-r--r--fs/ubifs/super.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 372c7fb6653..302a2056422 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1351,8 +1351,9 @@ static int mount_ubifs(struct ubifs_info *c)
x = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
ubifs_msg("journal size: %lld bytes (%lld KiB, %lld MiB, %d "
"LEBs)", x, x >> 10, x >> 20, c->log_lebs + c->max_bud_cnt);
- ubifs_msg("media format: %d (latest is %d)",
- c->fmt_version, UBIFS_FORMAT_VERSION);
+ ubifs_msg("media format: w%d/r%d (latest is w%d/r%d)",
+ c->fmt_version, c->ro_compat_version,
+ UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
ubifs_msg("default compressor: %s", ubifs_compr_name(c->default_compr));
ubifs_msg("reserved for root: %llu bytes (%llu KiB)",
c->report_rp_size, c->report_rp_size >> 10);
@@ -1492,6 +1493,15 @@ static int ubifs_remount_rw(struct ubifs_info *c)
{
int err, lnum;
+ if (c->rw_incompat) {
+ ubifs_err("the file-system is not R/W-compatible");
+ ubifs_msg("on-flash format version is w%d/r%d, but software "
+ "only supports up to version w%d/r%d", c->fmt_version,
+ c->ro_compat_version, UBIFS_FORMAT_VERSION,
+ UBIFS_RO_COMPAT_VERSION);
+ return -EROFS;
+ }
+
mutex_lock(&c->umount_mutex);
dbg_save_space_info(c);
c->remounting_rw = 1;