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authorChris Mason <clm@fb.com>2016-10-18 06:51:33 -0700
committerChris Mason <clm@fb.com>2016-10-18 06:51:33 -0700
commit112a3edf4bc687e02b9aa13c33391203fe6b7714 (patch)
treedc3ce4d41bf58f9f50e344788a758835837ea363 /fs/btrfs
parentd9ed71e5457c8c5bf1dc706e06468eab9e2aa87e (diff)
parentd5e84fd8d0634d056248b67463b42f6c85896a19 (diff)
Merge branch 'for-chris-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.9
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/send.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 978796865bfc..0b4628999b77 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -5805,6 +5805,64 @@ static int changed_extent(struct send_ctx *sctx,
int ret = 0;
if (sctx->cur_ino != sctx->cmp_key->objectid) {
+
+ if (result == BTRFS_COMPARE_TREE_CHANGED) {
+ struct extent_buffer *leaf_l;
+ struct extent_buffer *leaf_r;
+ struct btrfs_file_extent_item *ei_l;
+ struct btrfs_file_extent_item *ei_r;
+
+ leaf_l = sctx->left_path->nodes[0];
+ leaf_r = sctx->right_path->nodes[0];
+ ei_l = btrfs_item_ptr(leaf_l,
+ sctx->left_path->slots[0],
+ struct btrfs_file_extent_item);
+ ei_r = btrfs_item_ptr(leaf_r,
+ sctx->right_path->slots[0],
+ struct btrfs_file_extent_item);
+
+ /*
+ * We may have found an extent item that has changed
+ * only its disk_bytenr field and the corresponding
+ * inode item was not updated. This case happens due to
+ * very specific timings during relocation when a leaf
+ * that contains file extent items is COWed while
+ * relocation is ongoing and its in the stage where it
+ * updates data pointers. So when this happens we can
+ * safely ignore it since we know it's the same extent,
+ * but just at different logical and physical locations
+ * (when an extent is fully replaced with a new one, we
+ * know the generation number must have changed too,
+ * since snapshot creation implies committing the current
+ * transaction, and the inode item must have been updated
+ * as well).
+ * This replacement of the disk_bytenr happens at
+ * relocation.c:replace_file_extents() through
+ * relocation.c:btrfs_reloc_cow_block().
+ */
+ if (btrfs_file_extent_generation(leaf_l, ei_l) ==
+ btrfs_file_extent_generation(leaf_r, ei_r) &&
+ btrfs_file_extent_ram_bytes(leaf_l, ei_l) ==
+ btrfs_file_extent_ram_bytes(leaf_r, ei_r) &&
+ btrfs_file_extent_compression(leaf_l, ei_l) ==
+ btrfs_file_extent_compression(leaf_r, ei_r) &&
+ btrfs_file_extent_encryption(leaf_l, ei_l) ==
+ btrfs_file_extent_encryption(leaf_r, ei_r) &&
+ btrfs_file_extent_other_encoding(leaf_l, ei_l) ==
+ btrfs_file_extent_other_encoding(leaf_r, ei_r) &&
+ btrfs_file_extent_type(leaf_l, ei_l) ==
+ btrfs_file_extent_type(leaf_r, ei_r) &&
+ btrfs_file_extent_disk_bytenr(leaf_l, ei_l) !=
+ btrfs_file_extent_disk_bytenr(leaf_r, ei_r) &&
+ btrfs_file_extent_disk_num_bytes(leaf_l, ei_l) ==
+ btrfs_file_extent_disk_num_bytes(leaf_r, ei_r) &&
+ btrfs_file_extent_offset(leaf_l, ei_l) ==
+ btrfs_file_extent_offset(leaf_r, ei_r) &&
+ btrfs_file_extent_num_bytes(leaf_l, ei_l) ==
+ btrfs_file_extent_num_bytes(leaf_r, ei_r))
+ return 0;
+ }
+
inconsistent_snapshot_error(sctx, result, "extent");
return -EIO;
}