With version 2 of fastmap, flags are supported.
We fall back to scanning mode if unsupported flags are found.

Signed-off-by: Richard Weinberger <rich...@nod.at>
---
 drivers/mtd/ubi/fastmap.c   | 24 ++++++++++++++++++++----
 drivers/mtd/ubi/ubi-media.h | 11 +++++++++--
 drivers/mtd/ubi/ubi.h       |  2 ++
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 768fa8a76867..1ebb5d15ab1a 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -949,9 +949,24 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct 
ubi_attach_info *ai,
                goto free_fm_sb;
        }
 
-       if (fmsb->version != UBI_FM_FMT_VERSION) {
-               ubi_err(ubi, "bad fastmap version: %i, expected: %i",
-                       fmsb->version, UBI_FM_FMT_VERSION);
+       fm->flags = be32_to_cpu(fmsb->flags);
+
+       if (fmsb->version == 1) {
+               if (fm->flags != 0) {
+                       ubi_err(ubi, "fastmap flags are non-zero: %#x",
+                               fm->flags);
+                       ret = UBI_BAD_FASTMAP;
+                       goto free_fm_sb;
+               }
+       } else if (fmsb->version == 2) {
+               if ((fm->flags & UBI_FM_SB_FLG_MASK) != UBI_FM_SB_FLG_MASK) {
+                       ubi_err(ubi, "unsupported fastmap flags present: %#x",
+                               fm->flags);
+                       ret = UBI_BAD_FASTMAP;
+                       goto free_fm_sb;
+               }
+       } else {
+               ubi_err(ubi, "bad fastmap version: %i", fmsb->version);
                ret = UBI_BAD_FASTMAP;
                goto free_fm_sb;
        }
@@ -1229,10 +1244,11 @@ static int ubi_write_fastmap(struct ubi_device *ubi,
        ubi_assert(fm_pos <= ubi->fm_size);
 
        fmsb->magic = cpu_to_be32(UBI_FM_SB_MAGIC);
-       fmsb->version = UBI_FM_FMT_VERSION;
+       fmsb->version = UBI_FM_FMT_WRITE_VERSION;
        fmsb->used_blocks = cpu_to_be32(new_fm->used_blocks);
        /* the max sqnum will be filled in while *reading* the fastmap */
        fmsb->sqnum = 0;
+       fmsb->flags = 0;
 
        fmh->magic = cpu_to_be32(UBI_FM_HDR_MAGIC);
        free_peb_count = 0;
diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
index 195ff8ca8211..6136a97f4844 100644
--- a/drivers/mtd/ubi/ubi-media.h
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -365,7 +365,10 @@ struct ubi_vtbl_record {
 #define UBI_FM_DATA_VOLUME_ID  (UBI_LAYOUT_VOLUME_ID + 2)
 
 /* fastmap on-flash data structure format version */
-#define UBI_FM_FMT_VERSION     1
+#define UBI_FM_FMT_VERSION             2
+
+/* this implementation writes always version 1 */
+#define UBI_FM_FMT_WRITE_VERSION       1
 
 #define UBI_FM_SB_MAGIC                0x7B11D69F
 #define UBI_FM_HDR_MAGIC       0xD4B82EF7
@@ -387,6 +390,8 @@ struct ubi_vtbl_record {
 #define UBI_FM_MIN_POOL_SIZE   8
 #define UBI_FM_MAX_POOL_SIZE   256
 
+#define UBI_FM_SB_FLG_MASK     0
+
 /**
  * struct ubi_fm_sb - UBI fastmap super block
  * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC)
@@ -396,6 +401,7 @@ struct ubi_vtbl_record {
  * @block_loc: an array containing the location of all PEBs of the fastmap
  * @block_ec: the erase counter of each used PEB
  * @sqnum: highest sequence number value at the time while taking the fastmap
+ * @flags: fastmap specific flags, only used with @version > 1, zero otherwise
  *
  */
 struct ubi_fm_sb {
@@ -407,7 +413,8 @@ struct ubi_fm_sb {
        __be32 block_loc[UBI_FM_MAX_BLOCKS];
        __be32 block_ec[UBI_FM_MAX_BLOCKS];
        __be64 sqnum;
-       __u8 padding2[32];
+       __be32 flags;
+       __u8 padding2[28];
 } __packed;
 
 /**
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index f5ba97c46160..4fab3790733b 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -249,6 +249,7 @@ struct ubi_volume_desc;
  * @used_blocks: number of used PEBs
  * @max_pool_size: maximal size of the user pool
  * @max_wl_pool_size: maximal size of the pool used by the WL sub-system
+ * @flags: fastmap flags
  */
 struct ubi_fastmap_layout {
        struct ubi_wl_entry *e[UBI_FM_MAX_BLOCKS];
@@ -256,6 +257,7 @@ struct ubi_fastmap_layout {
        int used_blocks;
        int max_pool_size;
        int max_wl_pool_size;
+       int flags;
 };
 
 /**
-- 
2.13.6

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