UBI: Add fastmap stuff to attach.c

- Export compare_lebs() as fastmap needs this function.
- Implement fastmap scan logic.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

3 files changed, 260 insertions, 130 deletions

diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index f7adf53e4f45..fec406b4553d 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -300,7 +300,7 @@ static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
 }
 
 /**
- * compare_lebs - find out which logical eraseblock is newer.
+ * ubi_compare_lebs - find out which logical eraseblock is newer.
  * @ubi: UBI device description object
  * @aeb: first logical eraseblock to compare
  * @pnum: physical eraseblock number of the second logical eraseblock to
@@ -319,7 +319,7 @@ static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
  *     o bit 2 is cleared: the older LEB is not corrupted;
  *     o bit 2 is set: the older LEB is corrupted.
  */
-static int compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
+int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
                         int pnum, const struct ubi_vid_hdr *vid_hdr)
 {
         void *buf;
@@ -337,7 +337,7 @@ static int compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
                  * support these images anymore. Well, those images still work,
                  * but only if no unclean reboots happened.
                  */
-                ubi_err("unsupported on-flash UBI format\n");
+                ubi_err("unsupported on-flash UBI format");
                 return -EINVAL;
         }
 
@@ -507,7 +507,7 @@ int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
                  * sequence numbers. We still can attach these images, unless
                  * there is a need to distinguish between old and new
                  * eraseblocks, in which case we'll refuse the image in
-                 * 'compare_lebs()'. In other words, we attach old clean
+                 * 'ubi_compare_lebs()'. In other words, we attach old clean
                  * images, but refuse attaching old images with duplicated
                  * logical eraseblocks because there was an unclean reboot.
                  */
@@ -523,7 +523,7 @@ int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
                  * Now we have to drop the older one and preserve the newer
                  * one.
                  */
-                cmp_res = compare_lebs(ubi, aeb, pnum, vid_hdr);
+                cmp_res = ubi_compare_lebs(ubi, aeb, pnum, vid_hdr);
                 if (cmp_res < 0)
                         return cmp_res;
 
@@ -748,7 +748,7 @@ struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi,
 /**
  * check_corruption - check the data area of PEB.
  * @ubi: UBI device description object
- * @vid_hrd: the (corrupted) VID header of this PEB
+ * @vid_hdr: the (corrupted) VID header of this PEB
  * @pnum: the physical eraseblock number to check
  *
  * This is a helper function which is used to distinguish between VID header
@@ -810,6 +810,8 @@ out_unlock:
  * @ubi: UBI device description object
  * @ai: attaching information
  * @pnum: the physical eraseblock number
+ * @vid: The volume ID of the found volume will be stored in this pointer
+ * @sqnum: The sqnum of the found volume will be stored in this pointer
  *
  * This function reads UBI headers of PEB @pnum, checks them, and adds
  * information about this PEB to the corresponding list or RB-tree in the
@@ -817,10 +819,10 @@ out_unlock:
  * successfully handled and a negative error code in case of failure.
  */
 static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
-                    int pnum)
+                    int pnum, int *vid, unsigned long long *sqnum)
 {
         long long uninitialized_var(ec);
-        int err, bitflips = 0, vol_id, ec_err = 0;
+        int err, bitflips = 0, vol_id = -1, ec_err = 0;
 
         dbg_bld("scan PEB %d", pnum);
 
@@ -991,14 +993,21 @@ static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
         }
 
         vol_id = be32_to_cpu(vidh->vol_id);
+        if (vid)
+                *vid = vol_id;
+        if (sqnum)
+                *sqnum = be64_to_cpu(vidh->sqnum);
         if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
                 int lnum = be32_to_cpu(vidh->lnum);
 
                 /* Unsupported internal volume */
                 switch (vidh->compat) {
                 case UBI_COMPAT_DELETE:
-                        ubi_msg("\"delete\" compatible internal volume %d:%d found, will remove it",
-                                vol_id, lnum);
+                        if (vol_id != UBI_FM_SB_VOLUME_ID
+                            && vol_id != UBI_FM_DATA_VOLUME_ID) {
+                                ubi_msg("\"delete\" compatible internal volume %d:%d found, will remove it",
+                                        vol_id, lnum);
+                        }
                         err = add_to_list(ai, pnum, vol_id, lnum,
                                           ec, 1, &ai->erase);
                         if (err)
@@ -1121,51 +1130,126 @@ static int late_analysis(struct ubi_device *ubi, struct ubi_attach_info *ai)
 }
 
 /**
+ * destroy_av - free volume attaching information.
+ * @av: volume attaching information
+ * @ai: attaching information
+ *
+ * This function destroys the volume attaching information.
+ */
+static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
+{
+        struct ubi_ainf_peb *aeb;
+        struct rb_node *this = av->root.rb_node;
+
+        while (this) {
+                if (this->rb_left)
+                        this = this->rb_left;
+                else if (this->rb_right)
+                        this = this->rb_right;
+                else {
+                        aeb = rb_entry(this, struct ubi_ainf_peb, u.rb);
+                        this = rb_parent(this);
+                        if (this) {
+                                if (this->rb_left == &aeb->u.rb)
+                                        this->rb_left = NULL;
+                                else
+                                        this->rb_right = NULL;
+                        }
+
+                        kmem_cache_free(ai->aeb_slab_cache, aeb);
+                }
+        }
+        kfree(av);
+}
+
+/**
+ * destroy_ai - destroy attaching information.
+ * @ai: attaching information
+ */
+static void destroy_ai(struct ubi_attach_info *ai)
+{
+        struct ubi_ainf_peb *aeb, *aeb_tmp;
+        struct ubi_ainf_volume *av;
+        struct rb_node *rb;
+
+        list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) {
+                list_del(&aeb->u.list);
+                kmem_cache_free(ai->aeb_slab_cache, aeb);
+        }
+        list_for_each_entry_safe(aeb, aeb_tmp, &ai->erase, u.list) {
+                list_del(&aeb->u.list);
+                kmem_cache_free(ai->aeb_slab_cache, aeb);
+        }
+        list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) {
+                list_del(&aeb->u.list);
+                kmem_cache_free(ai->aeb_slab_cache, aeb);
+        }
+        list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) {
+                list_del(&aeb->u.list);
+                kmem_cache_free(ai->aeb_slab_cache, aeb);
+        }
+
+        /* Destroy the volume RB-tree */
+        rb = ai->volumes.rb_node;
+        while (rb) {
+                if (rb->rb_left)
+                        rb = rb->rb_left;
+                else if (rb->rb_right)
+                        rb = rb->rb_right;
+                else {
+                        av = rb_entry(rb, struct ubi_ainf_volume, rb);
+
+                        rb = rb_parent(rb);
+                        if (rb) {
+                                if (rb->rb_left == &av->rb)
+                                        rb->rb_left = NULL;
+                                else
+                                        rb->rb_right = NULL;
+                        }
+
+                        destroy_av(ai, av);
+                }
+        }
+
+        if (ai->aeb_slab_cache)
+                kmem_cache_destroy(ai->aeb_slab_cache);
+
+        kfree(ai);
+}
+
+/**
  * scan_all - scan entire MTD device.
  * @ubi: UBI device description object
+ * @ai: attach info object
+ * @start: start scanning at this PEB
  *
  * This function does full scanning of an MTD device and returns complete
  * information about it in form of a "struct ubi_attach_info" object. In case
  * of failure, an error code is returned.
  */
-static struct ubi_attach_info *scan_all(struct ubi_device *ubi)
+static int scan_all(struct ubi_device *ubi, struct ubi_attach_info *ai,
+                    int start)
 {
         int err, pnum;
         struct rb_node *rb1, *rb2;
         struct ubi_ainf_volume *av;
         struct ubi_ainf_peb *aeb;
-        struct ubi_attach_info *ai;
-
-        ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
-        if (!ai)
-                return ERR_PTR(-ENOMEM);
-
-        INIT_LIST_HEAD(&ai->corr);
-        INIT_LIST_HEAD(&ai->free);
-        INIT_LIST_HEAD(&ai->erase);
-        INIT_LIST_HEAD(&ai->alien);
-        ai->volumes = RB_ROOT;
 
         err = -ENOMEM;
-        ai->aeb_slab_cache = kmem_cache_create("ubi_aeb_slab_cache",
-                                               sizeof(struct ubi_ainf_peb),
-                                               0, 0, NULL);
-        if (!ai->aeb_slab_cache)
-                goto out_ai;
 
         ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
         if (!ech)
-                goto out_ai;
+                return err;
 
         vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
         if (!vidh)
                 goto out_ech;
 
-        for (pnum = 0; pnum < ubi->peb_count; pnum++) {
+        for (pnum = start; pnum < ubi->peb_count; pnum++) {
                 cond_resched();
 
                 dbg_gen("process PEB %d", pnum);
-                err = scan_peb(ubi, ai, pnum);
+                err = scan_peb(ubi, ai, pnum, NULL, NULL);
                 if (err < 0)
                         goto out_vidh;
         }
@@ -1210,32 +1294,144 @@ static struct ubi_attach_info *scan_all(struct ubi_device *ubi)
         ubi_free_vid_hdr(ubi, vidh);
         kfree(ech);
 
-        return ai;
+        return 0;
 
 out_vidh:
         ubi_free_vid_hdr(ubi, vidh);
 out_ech:
         kfree(ech);
-out_ai:
-        ubi_destroy_ai(ai);
-        return ERR_PTR(err);
+        return err;
+}
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+
+/**
+ * scan_fastmap - try to find a fastmap and attach from it.
+ * @ubi: UBI device description object
+ * @ai: attach info object
+ *
+ * Returns 0 on success, negative return values indicate an internal
+ * error.
+ * UBI_NO_FASTMAP denotes that no fastmap was found.
+ * UBI_BAD_FASTMAP denotes that the found fastmap was invalid.
+ */
+static int scan_fast(struct ubi_device *ubi, struct ubi_attach_info *ai)
+{
+        int err, pnum, fm_anchor = -1;
+        unsigned long long max_sqnum = 0;
+
+        err = -ENOMEM;
+
+        ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+        if (!ech)
+                goto out;
+
+        vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+        if (!vidh)
+                goto out_ech;
+
+        for (pnum = 0; pnum < UBI_FM_MAX_START; pnum++) {
+                int vol_id = -1;
+                unsigned long long sqnum = -1;
+                cond_resched();
+
+                dbg_gen("process PEB %d", pnum);
+                err = scan_peb(ubi, ai, pnum, &vol_id, &sqnum);
+                if (err < 0)
+                        goto out_vidh;
+
+                if (vol_id == UBI_FM_SB_VOLUME_ID && sqnum > max_sqnum) {
+                        max_sqnum = sqnum;
+                        fm_anchor = pnum;
+                }
+        }
+
+        ubi_free_vid_hdr(ubi, vidh);
+        kfree(ech);
+
+        if (fm_anchor < 0)
+                return UBI_NO_FASTMAP;
+
+        return ubi_scan_fastmap(ubi, ai, fm_anchor);
+
+out_vidh:
+        ubi_free_vid_hdr(ubi, vidh);
+out_ech:
+        kfree(ech);
+out:
+        return err;
+}
+
+#endif
+
+static struct ubi_attach_info *alloc_ai(const char *slab_name)
+{
+        struct ubi_attach_info *ai;
+
+        ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
+        if (!ai)
+                return ai;
+
+        INIT_LIST_HEAD(&ai->corr);
+        INIT_LIST_HEAD(&ai->free);
+        INIT_LIST_HEAD(&ai->erase);
+        INIT_LIST_HEAD(&ai->alien);
+        ai->volumes = RB_ROOT;
+        ai->aeb_slab_cache = kmem_cache_create(slab_name,
+                                               sizeof(struct ubi_ainf_peb),
+                                               0, 0, NULL);
+        if (!ai->aeb_slab_cache) {
+                kfree(ai);
+                ai = NULL;
+        }
+
+        return ai;
 }
 
 /**
  * ubi_attach - attach an MTD device.
  * @ubi: UBI device descriptor
+ * @force_scan: if set to non-zero attach by scanning
  *
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
-int ubi_attach(struct ubi_device *ubi)
+int ubi_attach(struct ubi_device *ubi, int force_scan)
 {
         int err;
         struct ubi_attach_info *ai;
 
-        ai = scan_all(ubi);
-        if (IS_ERR(ai))
-                return PTR_ERR(ai);
+        ai = alloc_ai("ubi_aeb_slab_cache");
+        if (!ai)
+                return -ENOMEM;
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+        /* On small flash devices we disable fastmap in any case. */
+        if ((int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd) <= UBI_FM_MAX_START) {
+                ubi->fm_disabled = 1;
+                force_scan = 1;
+        }
+
+        if (force_scan)
+                err = scan_all(ubi, ai, 0);
+        else {
+                err = scan_fast(ubi, ai);
+                if (err > 0) {
+                        if (err != UBI_NO_FASTMAP) {
+                                destroy_ai(ai);
+                                ai = alloc_ai("ubi_aeb_slab_cache2");
+                                if (!ai)
+                                        return -ENOMEM;
+                        }
+
+                        err = scan_all(ubi, ai, UBI_FM_MAX_START);
+                }
+        }
+#else
+        err = scan_all(ubi, ai, 0);
+#endif
+        if (err)
+                goto out_ai;
 
         ubi->bad_peb_count = ai->bad_peb_count;
         ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
@@ -1256,7 +1452,29 @@ int ubi_attach(struct ubi_device *ubi)
         if (err)
                 goto out_wl;
 
-        ubi_destroy_ai(ai);
+#ifdef CONFIG_MTD_UBI_FASTMAP
+        if (ubi->fm && ubi->dbg->chk_gen) {
+                struct ubi_attach_info *scan_ai;
+
+                scan_ai = alloc_ai("ubi_ckh_aeb_slab_cache");
+                if (!scan_ai)
+                        goto out_wl;
+
+                err = scan_all(ubi, scan_ai, 0);
+                if (err) {
+                        destroy_ai(scan_ai);
+                        goto out_wl;
+                }
+
+                err = self_check_eba(ubi, ai, scan_ai);
+                destroy_ai(scan_ai);
+
+                if (err)
+                        goto out_wl;
+        }
+#endif
+
+        destroy_ai(ai);
         return 0;
 
 out_wl:
@@ -1265,99 +1483,11 @@ out_vtbl:
         ubi_free_internal_volumes(ubi);
         vfree(ubi->vtbl);
 out_ai:
-        ubi_destroy_ai(ai);
+        destroy_ai(ai);
         return err;
 }
 
 /**
- * destroy_av - free volume attaching information.
- * @av: volume attaching information
- * @ai: attaching information
- *
- * This function destroys the volume attaching information.
- */
-static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
-{
-        struct ubi_ainf_peb *aeb;
-        struct rb_node *this = av->root.rb_node;
-
-        while (this) {
-                if (this->rb_left)
-                        this = this->rb_left;
-                else if (this->rb_right)
-                        this = this->rb_right;
-                else {
-                        aeb = rb_entry(this, struct ubi_ainf_peb, u.rb);
-                        this = rb_parent(this);
-                        if (this) {
-                                if (this->rb_left == &aeb->u.rb)
-                                        this->rb_left = NULL;
-                                else
-                                        this->rb_right = NULL;
-                        }
-
-                        kmem_cache_free(ai->aeb_slab_cache, aeb);
-                }
-        }
-        kfree(av);
-}
-
-/**
- * ubi_destroy_ai - destroy attaching information.
- * @ai: attaching information
- */
-void ubi_destroy_ai(struct ubi_attach_info *ai)
-{
-        struct ubi_ainf_peb *aeb, *aeb_tmp;
-        struct ubi_ainf_volume *av;
-        struct rb_node *rb;
-
-        list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) {
-                list_del(&aeb->u.list);
-                kmem_cache_free(ai->aeb_slab_cache, aeb);
-        }
-        list_for_each_entry_safe(aeb, aeb_tmp, &ai->erase, u.list) {
-                list_del(&aeb->u.list);
-                kmem_cache_free(ai->aeb_slab_cache, aeb);
-        }
-        list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) {
-                list_del(&aeb->u.list);
-                kmem_cache_free(ai->aeb_slab_cache, aeb);
-        }
-        list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) {
-                list_del(&aeb->u.list);
-                kmem_cache_free(ai->aeb_slab_cache, aeb);
-        }
-
-        /* Destroy the volume RB-tree */
-        rb = ai->volumes.rb_node;
-        while (rb) {
-                if (rb->rb_left)
-                        rb = rb->rb_left;
-                else if (rb->rb_right)
-                        rb = rb->rb_right;
-                else {
-                        av = rb_entry(rb, struct ubi_ainf_volume, rb);
-
-                        rb = rb_parent(rb);
-                        if (rb) {
-                                if (rb->rb_left == &av->rb)
-                                        rb->rb_left = NULL;
-                                else
-                                        rb->rb_right = NULL;
-                        }
-
-                        destroy_av(ai, av);
-                }
-        }
-
-        if (ai->aeb_slab_cache)
-                kmem_cache_destroy(ai->aeb_slab_cache);
-
-        kfree(ai);
-}
-
-/**
  * self_check_ai - check the attaching information.
  * @ubi: UBI device description object
  * @ai: attaching information
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index c9b99be8f6d5..344b4cb49d4e 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -990,7 +990,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
         if (err)
                 goto out_free;
 
-        err = ubi_attach(ubi);
+        err = ubi_attach(ubi, 0);
         if (err) {
                 ubi_err("failed to attach mtd%d, error %d", mtd->index, err);
                 goto out_debugging;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index b0d3ba2a3dea..7d57469723cf 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -710,7 +710,7 @@ struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
 void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av);
 struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi,
                                        struct ubi_attach_info *ai);
-int ubi_attach(struct ubi_device *ubi);
+int ubi_attach(struct ubi_device *ubi, int force_scan);
 void ubi_destroy_ai(struct ubi_attach_info *ai);
 
 /* vtbl.c */