Base on [PATCH] Btrfs: incremental send, check if orphanized dir inode needs 
delayed rename

Example1:
There's one case where we can't issue a rename operation for a directory
immediately when we process it. 

Parent snapshot:
|---- d/ (ino 257)
  |---- p1 (ino 258)
|---- p1/ (ino 259)

Send snapshot:
|---- d/ (ino 257)
  |---- p1 (ino 259)
    |---- p1/ (ino 258)

Here we can not rename 258 from d/p1 to p1/p1 without the rename of inode 259.
p1 258 is put into wait_parent_move. 259 can't be rename to d/p1, so it is put 
into
circular waiting happens. This is fix by rename destination directory and set 
it as orphanized for this case.

Example2:
There's one case where we can't issue a rename operation for a directory
immediately we process it.
After moving 262 outside, path of 265 is stored in the name_cache_entry.
When 263 try to overwrite 265, its ancestor, 265 is moved to orphanized. Path 
of 263
is still the original path, however. This causes error.

Parent snapshot:
|---- a/ (ino 259)
  |---- c (ino 266)
|---- d/ (ino 260)
  |---- ance (ino 265)
    |---- e (ino 261)
    |---- f (ino 262)
    |---- ance (ino 263)

Send snapshot:
|---- a/ (ino 259)
|---- c/ (ino 266)
  |---- ance (ino 265)
|---- d/ (ino 260)
  |---- ance (ino 263)
|---- f/ (ino 262)
  |---- e (ino 261)

Signed-off-by: Robbie Ko <[email protected]>
---
 fs/btrfs/send.c | 45 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 1c1f161..fbfbb8b 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -230,7 +230,6 @@ struct pending_dir_move {
        u64 parent_ino;
        u64 ino;
        u64 gen;
-       bool is_orphan;
        struct list_head update_refs;
 };
 
@@ -1840,7 +1839,7 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 
dir, u64 dir_gen,
         * was already unlinked/moved, so we can safely assume that we will not
         * overwrite anything at this point in time.
         */
-       if (other_inode > sctx->send_progress) {
+       if (other_inode > sctx->send_progress || is_waiting_for_move(sctx, 
other_inode)) {
                ret = get_inode_info(sctx->parent_root, other_inode, NULL,
                                who_gen, NULL, NULL, NULL, NULL);
                if (ret < 0)
@@ -3014,7 +3013,6 @@ static int add_pending_dir_move(struct send_ctx *sctx,
        pm->parent_ino = parent_ino;
        pm->ino = ino;
        pm->gen = ino_gen;
-       pm->is_orphan = is_orphan;
        INIT_LIST_HEAD(&pm->list);
        INIT_LIST_HEAD(&pm->update_refs);
        RB_CLEAR_NODE(&pm->node);
@@ -3091,6 +3089,7 @@ static int apply_dir_move(struct send_ctx *sctx, struct 
pending_dir_move *pm)
        struct waiting_dir_move *dm = NULL;
        u64 rmdir_ino = 0;
        int ret;
+       bool is_orphan;
 
        name = fs_path_alloc();
        from_path = fs_path_alloc();
@@ -3102,9 +3101,10 @@ static int apply_dir_move(struct send_ctx *sctx, struct 
pending_dir_move *pm)
        dm = get_waiting_dir_move(sctx, pm->ino);
        ASSERT(dm);
        rmdir_ino = dm->rmdir_ino;
+       is_orphan = dm->orphanized;
        free_waiting_dir_move(sctx, dm);
 
-       if (pm->is_orphan) {
+       if (is_orphan) {
                ret = gen_unique_name(sctx, pm->ino,
                                      pm->gen, from_path);
        } else {
@@ -3292,6 +3292,7 @@ static int wait_for_dest_dir_move(struct send_ctx *sctx,
        u64 left_gen;
        u64 right_gen;
        int ret = 0;
+       struct waiting_dir_move *wdm;
 
        if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves))
                return 0;
@@ -3350,7 +3351,8 @@ static int wait_for_dest_dir_move(struct send_ctx *sctx,
                goto out;
        }
 
-       if (is_waiting_for_move(sctx, di_key.objectid)) {
+       wdm = get_waiting_dir_move(sctx, di_key.objectid);
+       if (wdm && !wdm->orphanized) {
                ret = add_pending_dir_move(sctx,
                                           sctx->cur_ino,
                                           sctx->cur_inode_gen,
@@ -3610,11 +3612,33 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", 
sctx->cur_ino);
                                goto out;
                        if (ret) {
                                struct name_cache_entry *nce;
+                               struct waiting_dir_move *wdm;
+                               bool cur_is_ancestor = false;
+
+                               /*
+                                * check is dset path is ancestor src path
+                                * if yes, need to update cur_ino path
+                                */
+                               if (strncmp(cur->full_path->start, 
valid_path->start, fs_path_len(cur->full_path)) == 0 &&
+                                                       fs_path_len(valid_path) 
> fs_path_len(cur->full_path) && valid_path->start[fs_path_len(cur->full_path)] 
== '/') {
+                                       cur_is_ancestor = true;
+                               }
 
                                ret = orphanize_inode(sctx, ow_inode, ow_gen,
                                                cur->full_path);
                                if (ret < 0)
                                        goto out;
+
+                               /*
+                                * check is waiting dir, if yes change the ino
+                                * to orphanized in the waiting tree.
+                                */
+                               if (is_waiting_for_move(sctx, ow_inode)) {
+                                       wdm = get_waiting_dir_move(sctx, 
ow_inode);
+                                       ASSERT(wdm);
+                                       wdm->orphanized = true;
+                               }
+
                                /*
                                 * Make sure we clear our orphanized inode's
                                 * name from the name cache. This is because the
@@ -3630,6 +3654,17 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", 
sctx->cur_ino);
                                        name_cache_delete(sctx, nce);
                                        kfree(nce);
                                }
+
+                               /*
+                                * if ow_inode is ancestor cur_ino, need to 
update
+                                * update cur_ino path.
+                                */
+                               if (cur_is_ancestor) {
+                                       fs_path_reset(valid_path);
+                                       ret = get_cur_path(sctx, sctx->cur_ino, 
sctx->cur_inode_gen, valid_path);
+                                       if (ret < 0)
+                                               goto out;
+                               }
                        } else {
                                ret = send_unlink(sctx, cur->full_path);
                                if (ret < 0)
-- 
1.9.1

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