Merge branch 'send_fixes_4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.2

1 files changed, 83 insertions, 21 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 5cf7838fb5e5..50ebc622a324 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -243,6 +243,7 @@ struct waiting_dir_move {
          * after this directory is moved, we can try to rmdir the ino rmdir_ino.
          */
         u64 rmdir_ino;
+        bool orphanized;
 };
 
 struct orphan_dir_info {
@@ -1916,8 +1917,13 @@ static int did_overwrite_ref(struct send_ctx *sctx,
                 goto out;
         }
 
-        /* we know that it is or will be overwritten. check this now */
-        if (ow_inode < sctx->send_progress)
+        /*
+         * We know that it is or will be overwritten. Check this now.
+         * The current inode being processed might have been the one that caused
+         * inode 'ino' to be orphanized, therefore ow_inode can actually be the
+         * same as sctx->send_progress.
+         */
+        if (ow_inode <= sctx->send_progress)
                 ret = 1;
         else
                 ret = 0;
@@ -2239,6 +2245,8 @@ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
         fs_path_reset(dest);
 
         while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
+                struct waiting_dir_move *wdm;
+
                 fs_path_reset(name);
 
                 if (is_waiting_for_rm(sctx, ino)) {
@@ -2249,7 +2257,11 @@ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
                         break;
                 }
 
-                if (is_waiting_for_move(sctx, ino)) {
+                wdm = get_waiting_dir_move(sctx, ino);
+                if (wdm && wdm->orphanized) {
+                        ret = gen_unique_name(sctx, ino, gen, name);
+                        stop = 1;
+                } else if (wdm) {
                         ret = get_first_ref(sctx->parent_root, ino,
                                             &parent_inode, &parent_gen, name);
                 } else {
@@ -2939,7 +2951,7 @@ static int is_waiting_for_move(struct send_ctx *sctx, u64 ino)
         return entry != NULL;
 }
 
-static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino)
+static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized)
 {
         struct rb_node **p = &sctx->waiting_dir_moves.rb_node;
         struct rb_node *parent = NULL;
@@ -2950,6 +2962,7 @@ static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino)
                 return -ENOMEM;
         dm->ino = ino;
         dm->rmdir_ino = 0;
+        dm->orphanized = orphanized;
 
         while (*p) {
                 parent = *p;
@@ -3046,7 +3059,7 @@ static int add_pending_dir_move(struct send_ctx *sctx,
                         goto out;
         }
 
-        ret = add_waiting_dir_move(sctx, pm->ino);
+        ret = add_waiting_dir_move(sctx, pm->ino, is_orphan);
         if (ret)
                 goto out;
 
@@ -3369,8 +3382,40 @@ out:
         return ret;
 }
 
+/*
+ * Check if ino ino1 is an ancestor of inode ino2 in the given root.
+ * Return 1 if true, 0 if false and < 0 on error.
+ */
+static int is_ancestor(struct btrfs_root *root,
+                       const u64 ino1,
+                       const u64 ino1_gen,
+                       const u64 ino2,
+                       struct fs_path *fs_path)
+{
+        u64 ino = ino2;
+
+        while (ino > BTRFS_FIRST_FREE_OBJECTID) {
+                int ret;
+                u64 parent;
+                u64 parent_gen;
+
+                fs_path_reset(fs_path);
+                ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
+                if (ret < 0) {
+                        if (ret == -ENOENT && ino == ino2)
+                                ret = 0;
+                        return ret;
+                }
+                if (parent == ino1)
+                        return parent_gen == ino1_gen ? 1 : 0;
+                ino = parent;
+        }
+        return 0;
+}
+
 static int wait_for_parent_move(struct send_ctx *sctx,
-                                struct recorded_ref *parent_ref)
+                                struct recorded_ref *parent_ref,
+                                const bool is_orphan)
 {
         int ret = 0;
         u64 ino = parent_ref->dir;
@@ -3390,11 +3435,24 @@ static int wait_for_parent_move(struct send_ctx *sctx,
          * Our current directory inode may not yet be renamed/moved because some
          * ancestor (immediate or not) has to be renamed/moved first. So find if
          * such ancestor exists and make sure our own rename/move happens after
-         * that ancestor is processed.
+         * that ancestor is processed to avoid path build infinite loops (done
+         * at get_cur_path()).
          */
         while (ino > BTRFS_FIRST_FREE_OBJECTID) {
                 if (is_waiting_for_move(sctx, ino)) {
-                        ret = 1;
+                        /*
+                         * If the current inode is an ancestor of ino in the
+                         * parent root, we need to delay the rename of the
+                         * current inode, otherwise don't delayed the rename
+                         * because we can end up with a circular dependency
+                         * of renames, resulting in some directories never
+                         * getting the respective rename operations issued in
+                         * the send stream or getting into infinite path build
+                         * loops.
+                         */
+                        ret = is_ancestor(sctx->parent_root,
+                                          sctx->cur_ino, sctx->cur_inode_gen,
+                                          ino, path_before);
                         break;
                 }
 
@@ -3436,7 +3494,7 @@ out:
                                            ino,
                                            &sctx->new_refs,
                                            &sctx->deleted_refs,
-                                           false);
+                                           is_orphan);
                 if (!ret)
                         ret = 1;
         }
@@ -3605,6 +3663,17 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
                         }
                 }
 
+                if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root &&
+                    can_rename) {
+                        ret = wait_for_parent_move(sctx, cur, is_orphan);
+                        if (ret < 0)
+                                goto out;
+                        if (ret == 1) {
+                                can_rename = false;
+                                *pending_move = 1;
+                        }
+                }
+
                 /*
                  * link/move the ref to the new place. If we have an orphan
                  * inode, move it and update valid_path. If not, link or move
@@ -3625,18 +3694,11 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
                                  * dirs, we always have one new and one deleted
                                  * ref. The deleted ref is ignored later.
                                  */
-                                ret = wait_for_parent_move(sctx, cur);
-                                if (ret < 0)
-                                        goto out;
-                                if (ret) {
-                                        *pending_move = 1;
-                                } else {
-                                        ret = send_rename(sctx, valid_path,
-                                                          cur->full_path);
-                                        if (!ret)
-                                                ret = fs_path_copy(valid_path,
-                                                               cur->full_path);
-                                }
+                                ret = send_rename(sctx, valid_path,
+                                                  cur->full_path);
+                                if (!ret)
+                                        ret = fs_path_copy(valid_path,
+                                                           cur->full_path);
                                 if (ret < 0)
                                         goto out;
                         } else {