Btrfs: fix send issuing outdated paths for utimes, chown and chmod

When doing an incremental send, if we had a directory pending a move/rename
operation and none of its parents, except for the immediate parent, were
pending a move/rename, after processing the directory's references, we would
be issuing utimes, chown and chmod intructions against am outdated path - a
path which matched the one in the parent root.

This change also simplifies a bit the code that deals with building a path
for a directory which has a move/rename operation delayed.

Steps to reproduce:

    $ mkfs.btrfs -f /dev/sdb3
    $ mount /dev/sdb3 /mnt/btrfs
    $ mkdir -p /mnt/btrfs/a/b/c/d/e
    $ mkdir /mnt/btrfs/a/b/c/f
    $ chmod 0777 /mnt/btrfs/a/b/c/d/e
    $ btrfs subvolume snapshot -r /mnt/btrfs /mnt/btrfs/snap1
    $ btrfs send /mnt/btrfs/snap1 -f /tmp/base.send
    $ mv /mnt/btrfs/a/b/c/f /mnt/btrfs/a/b/f2
    $ mv /mnt/btrfs/a/b/c/d/e /mnt/btrfs/a/b/f2/e2
    $ mv /mnt/btrfs/a/b/c /mnt/btrfs/a/b/c2
    $ mv /mnt/btrfs/a/b/c2/d /mnt/btrfs/a/b/c2/d2
    $ chmod 0700 /mnt/btrfs/a/b/f2/e2
    $ btrfs subvolume snapshot -r /mnt/btrfs /mnt/btrfs/snap2
    $ btrfs send -p /mnt/btrfs/snap1 /mnt/btrfs/snap2 -f /tmp/incremental.send

    $ umount /mnt/btrfs
    $ mkfs.btrfs -f /dev/sdb3
    $ mount /dev/sdb3 /mnt/btrfs
    $ btrfs receive /mnt/btrfs -f /tmp/base.send
    $ btrfs receive /mnt/btrfs -f /tmp/incremental.send

The second btrfs receive command failed with:

    ERROR: chmod a/b/c/d/e failed. No such file or directory

A test case for xfstests follows.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>

1 files changed, 12 insertions, 19 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 46c6b5442f20..298e25de13ab 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -2000,7 +2000,6 @@ static void name_cache_free(struct send_ctx *sctx)
  */
 static int __get_cur_name_and_parent(struct send_ctx *sctx,
                                      u64 ino, u64 gen,
-                                     int skip_name_cache,
                                      u64 *parent_ino,
                                      u64 *parent_gen,
                                      struct fs_path *dest)
@@ -2010,8 +2009,6 @@ static int __get_cur_name_and_parent(struct send_ctx *sctx,
         struct btrfs_path *path = NULL;
         struct name_cache_entry *nce = NULL;
 
-        if (skip_name_cache)
-                goto get_ref;
         /*
          * First check if we already did a call to this function with the same
          * ino/gen. If yes, check if the cache entry is still up-to-date. If yes
@@ -2056,12 +2053,11 @@ static int __get_cur_name_and_parent(struct send_ctx *sctx,
                 goto out_cache;
         }
 
-get_ref:
         /*
          * Depending on whether the inode was already processed or not, use
          * send_root or parent_root for ref lookup.
          */
-        if (ino < sctx->send_progress && !skip_name_cache)
+        if (ino < sctx->send_progress)
                 ret = get_first_ref(sctx->send_root, ino,
                                     parent_ino, parent_gen, dest);
         else
@@ -2085,8 +2081,6 @@ get_ref:
                         goto out;
                 ret = 1;
         }
-        if (skip_name_cache)
-                goto out;
 
 out_cache:
         /*
@@ -2154,7 +2148,6 @@ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
         u64 parent_inode = 0;
         u64 parent_gen = 0;
         int stop = 0;
-        int skip_name_cache = 0;
 
         name = fs_path_alloc();
         if (!name) {
@@ -2162,9 +2155,6 @@ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
                 goto out;
         }
 
-        if (is_waiting_for_move(sctx, ino))
-                skip_name_cache = 1;
-
         dest->reversed = 1;
         fs_path_reset(dest);
 
@@ -2179,16 +2169,19 @@ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
                         break;
                 }
 
-                ret = __get_cur_name_and_parent(sctx, ino, gen, skip_name_cache,
-                                &parent_inode, &parent_gen, name);
+                if (is_waiting_for_move(sctx, ino)) {
+                        ret = get_first_ref(sctx->parent_root, ino,
+                                            &parent_inode, &parent_gen, name);
+                } else {
+                        ret = __get_cur_name_and_parent(sctx, ino, gen,
+                                                        &parent_inode,
+                                                        &parent_gen, name);
+                        if (ret)
+                                stop = 1;
+                }
+
                 if (ret < 0)
                         goto out;
-                if (ret)
-                        stop = 1;
-
-                if (!skip_name_cache &&
-                    is_waiting_for_move(sctx, parent_inode))
-                        skip_name_cache = 1;
 
                 ret = fs_path_add_path(dest, name);
                 if (ret < 0)