Unlike lowmem mode check, we don't have good place for original mode to
check overlap dev extents.

So this patch introduces a new function, btrfs_check_dev_extents(), to
handle possible bad dev extents.

Reported-by: Hans van Kranenburg <hans.van.kranenb...@mendix.com>
Signed-off-by: Qu Wenruo <w...@suse.com>
---
 check/main.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/check/main.c b/check/main.c
index bc2ee22f7943..ff9a785ce555 100644
--- a/check/main.c
+++ b/check/main.c
@@ -8224,6 +8224,99 @@ out:
        return ret;
 }
 
+/*
+ * Check if all dev extents are valid (not overlap nor beyond device
+ * boundary).
+ *
+ * Dev extents <-> chunk cross checking is already done in check_chunks().
+ */
+static int check_dev_extents(struct btrfs_fs_info *fs_info)
+{
+       struct btrfs_path path;
+       struct btrfs_key key;
+       struct btrfs_root *dev_root = fs_info->dev_root;
+       int ret;
+       u64 prev_devid = 0;
+       u64 prev_dev_ext_end = 0;
+
+       btrfs_init_path(&path);
+
+       key.objectid = 1;
+       key.type = BTRFS_DEV_EXTENT_KEY;
+       key.offset = 0;
+
+       ret = btrfs_search_slot(NULL, dev_root, &key, &path, 0, 0);
+       if (ret < 0) {
+               error("failed to search device tree: %s", strerror(-ret));
+               goto out;
+       }
+       if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+               ret = btrfs_next_leaf(dev_root, &path);
+               if (ret < 0) {
+                       error("failed to find next leaf: %s", strerror(-ret));
+                       goto out;
+               }
+               if (ret > 0) {
+                       ret = 0;
+                       goto out;
+               }
+       }
+
+       while (1) {
+               struct btrfs_dev_extent *dev_ext;
+               struct btrfs_device *dev;
+               u64 devid;
+               u64 physical_offset;
+               u64 physical_len;
+
+               btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+               if (key.type != BTRFS_DEV_EXTENT_KEY)
+                       break;
+               dev_ext = btrfs_item_ptr(path.nodes[0], path.slots[0],
+                                        struct btrfs_dev_extent);
+               devid = key.objectid;
+               physical_offset = key.offset;
+               physical_len = btrfs_dev_extent_length(path.nodes[0], dev_ext);
+
+               dev = btrfs_find_device(fs_info, devid, NULL, NULL);
+               if (!dev) {
+                       error("failed to find device with devid %llu", devid);
+                       ret = -EUCLEAN;
+                       goto out;
+               }
+               if (prev_devid == devid && prev_dev_ext_end > physical_offset) {
+                       error(
+"dev extent devid %llu physical offset %llu overlap with previous dev extent 
end %llu",
+                             devid, physical_offset, prev_dev_ext_end);
+                       ret = -EUCLEAN;
+                       goto out;
+               }
+               if (physical_offset + physical_len > dev->total_bytes) {
+                       error(
+"dev extent devid %llu physical offset %llu len %llu is beyond device boudnary 
%llu",
+                             devid, physical_offset, physical_len,
+                             dev->total_bytes);
+                       ret = -EUCLEAN;
+                       goto out;
+               }
+               prev_devid = devid;
+               prev_dev_ext_end = physical_offset + physical_len;
+
+               ret = btrfs_next_item(dev_root, &path);
+               if (ret < 0) {
+                       error("failed to find next leaf: %s", strerror(-ret));
+                       goto out;
+               }
+               if (ret > 0) {
+                       ret = 0;
+                       break;
+               }
+       }
+out:
+       btrfs_release_path(&path);
+       return ret;
+}
+
 static int check_chunks_and_extents(struct btrfs_fs_info *fs_info)
 {
        struct rb_root dev_cache;
@@ -8318,6 +8411,12 @@ again:
                goto out;
        }
 
+       ret = check_dev_extents(fs_info);
+       if (ret < 0) {
+               err = ret;
+               goto out;
+       }
+
        ret = check_chunks(&chunk_cache, &block_group_cache,
                           &dev_extent_cache, NULL, NULL, NULL, 0);
        if (ret) {
-- 
2.19.1

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