diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 89116afda7a20ff48f41e95a5f6e0ba8ff3da8d6..e5d85311d5d5d4eadd857fda99a99bd881074b38 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1483,7 +1483,7 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
ulist_init(roots);
ulist_init(tmp);
- trans = btrfs_attach_transaction(root);
+ trans = btrfs_join_transaction_nostart(root);
if (IS_ERR(trans)) {
if (PTR_ERR(trans) != -ENOENT && PTR_ERR(trans) != -EROFS) {
ret = PTR_ERR(trans);
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 69b59bf75882eff54415e03ef08943db946ef087..c3c0c064c25dadd317841e1d2761e2629b6ec9f3 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -6322,68 +6322,21 @@ 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)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 3b8ae1a8f02df77769542a3c0a0782f452c8c791..e3adb714c04b364869e9da5c36e2f9fa0157b7fb 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -28,15 +28,18 @@ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
[TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
[TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
__TRANS_ATTACH |
- __TRANS_JOIN),
+ __TRANS_JOIN |
+ __TRANS_JOIN_NOSTART),
[TRANS_STATE_UNBLOCKED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
- __TRANS_JOIN_NOLOCK),
+ __TRANS_JOIN_NOLOCK |
+ __TRANS_JOIN_NOSTART),
[TRANS_STATE_COMPLETED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
- __TRANS_JOIN_NOLOCK),
+ __TRANS_JOIN_NOLOCK |
+ __TRANS_JOIN_NOSTART),
};
void btrfs_put_transaction(struct btrfs_transaction *transaction)
@@ -543,7 +546,8 @@ start_transaction(struct btrfs_root *root, unsigned int num_items,
ret = join_transaction(fs_info, type);
if (ret == -EBUSY) {
wait_current_trans(fs_info);
- if (unlikely(type == TRANS_ATTACH))
+ if (unlikely(type == TRANS_ATTACH ||
+ type == TRANS_JOIN_NOSTART))
ret = -ENOENT;
}
} while (ret == -EBUSY);
@@ -659,6 +663,16 @@ struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root
BTRFS_RESERVE_NO_FLUSH, true);
}
+/*
+ * Similar to regular join but it never starts a transaction when none is
+ * running or after waiting for the current one to finish.
+ */
+struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
+{
+ return start_transaction(root, 0, TRANS_JOIN_NOSTART,
+ BTRFS_RESERVE_NO_FLUSH, true);
+}
+
/*
* btrfs_attach_transaction() - catch the running transaction
*
@@ -2037,6 +2051,16 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
}
} else {
spin_unlock(&fs_info->trans_lock);
+ /*
+ * The previous transaction was aborted and was already removed
+ * from the list of transactions at fs_info->trans_list. So we
+ * abort to prevent writing a new superblock that reflects a
+ * corrupt state (pointing to trees with unwritten nodes/leafs).
+ */
+ if (test_bit(BTRFS_FS_STATE_TRANS_ABORTED, &fs_info->fs_state)) {
+ ret = -EROFS;
+ goto cleanup_transaction;
+ }
}
extwriter_counter_dec(cur_trans, trans->type);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 527ea94b57d91a6c289cb4b4b67f6a07ecb85934..2c5a6f6e5bb0904eecef07941f9ad76f3ba2f036 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -94,11 +94,13 @@ struct btrfs_transaction {
#define __TRANS_JOIN (1U << 11)
#define __TRANS_JOIN_NOLOCK (1U << 12)
#define __TRANS_DUMMY (1U << 13)
+#define __TRANS_JOIN_NOSTART (1U << 14)
#define TRANS_START (__TRANS_START | __TRANS_FREEZABLE)
#define TRANS_ATTACH (__TRANS_ATTACH)
#define TRANS_JOIN (__TRANS_JOIN | __TRANS_FREEZABLE)
#define TRANS_JOIN_NOLOCK (__TRANS_JOIN_NOLOCK)
+#define TRANS_JOIN_NOSTART (__TRANS_JOIN_NOSTART)
#define TRANS_EXTWRITERS (__TRANS_START | __TRANS_ATTACH)
@@ -183,6 +185,7 @@ struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
int min_factor);
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);
+struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_attach_transaction_barrier(
struct btrfs_root *root);