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authorFilipe Manana <fdmanana@suse.com>2019-08-16 16:51:45 +0100
committerFilipe Manana <fdmanana@suse.com>2019-08-16 16:51:45 +0100
commit0acdee9607d3ccb518c735c26deece037c74e3fa (patch)
treef80dffa501e3732d9f196e514fd45d203c50b561
parent38ff7a409cc7bac20ed19084147a9bfe3e8072a3 (diff)
Btrfs: fix incremental send failure after deduplication
(bsc#1145940). suse-commit: e44b16efbda74e0ba684021dc3645dbfe6106c87
-rw-r--r--fs/btrfs/send.c77
1 files changed, 15 insertions, 62 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index bb1861ca7ddf..a3dd934ad293 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -6250,68 +6250,21 @@ 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;
- }
+ /*
+ * We have found an extent item that changed without the inode item
+ * having changed. This can happen either after relocation (where the
+ * disk_bytenr of an extent item is replaced at
+ * relocation.c:replace_file_extents()) or after deduplication into a
+ * file in both the parent and send snapshots (where an extent item can
+ * get modified or replaced with a new one). Note that deduplication
+ * updates the inode item, but it only changes the iversion (sequence
+ * field in the inode item) of the inode, so if a file is deduplicated
+ * the same amount of times in both the parent and send snapshots, its
+ * iversion becames the same in both snapshots, whence the inode item is
+ * the same on both snapshots.
+ */
+ if (sctx->cur_ino != sctx->cmp_key->objectid)
+ return 0;
if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
if (result != BTRFS_COMPARE_TREE_DELETED)