Btrfs: fix cur_ino < parent_ino case for send/receive

When the current inodes inum is smaller then the inum of the
parent directory strange things were happending due to wrong
path resolution and other bugs. Fix this with a new approach
for the problem.

Reported-by: Alex Lyakas <alex.bolshoy.btrfs@gmail.com>
Signed-off-by: Alexander Block <ablock84@googlemail.com>

1 files changed, 146 insertions, 244 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 5721401548e8..a5fae484d4e1 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -107,7 +107,6 @@ struct send_ctx {
         int cur_inode_new;
         int cur_inode_new_gen;
         int cur_inode_deleted;
-        int cur_inode_first_ref_orphan;
         u64 cur_inode_size;
         u64 cur_inode_mode;
 
@@ -2296,25 +2295,25 @@ out:
  * a valid path yet because we did not process the refs yet. So, the inode
  * is created as orphan.
  */
-static int send_create_inode(struct send_ctx *sctx, struct btrfs_path *path,
-                             struct btrfs_key *key)
+static int send_create_inode(struct send_ctx *sctx, u64 ino)
 {
         int ret = 0;
-        struct extent_buffer *eb = path->nodes[0];
-        struct btrfs_inode_item *ii;
         struct fs_path *p;
-        int slot = path->slots[0];
         int cmd;
+        u64 gen;
         u64 mode;
+        u64 rdev;
 
-verbose_printk("btrfs: send_create_inode %llu\n", sctx->cur_ino);
+verbose_printk("btrfs: send_create_inode %llu\n", ino);
 
         p = fs_path_alloc(sctx);
         if (!p)
                 return -ENOMEM;
 
-        ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
-        mode = btrfs_inode_mode(eb, ii);
+        ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode, NULL,
+                        NULL, &rdev);
+        if (ret < 0)
+                goto out;
 
         if (S_ISREG(mode))
                 cmd = BTRFS_SEND_C_MKFILE;
@@ -2339,22 +2338,22 @@ verbose_printk("btrfs: send_create_inode %llu\n", sctx->cur_ino);
         if (ret < 0)
                 goto out;
 
-        ret = gen_unique_name(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+        ret = gen_unique_name(sctx, ino, gen, p);
         if (ret < 0)
                 goto out;
 
         TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
-        TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, sctx->cur_ino);
+        TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
 
         if (S_ISLNK(mode)) {
                 fs_path_reset(p);
-                ret = read_symlink(sctx, sctx->send_root, sctx->cur_ino, p);
+                ret = read_symlink(sctx, sctx->send_root, ino, p);
                 if (ret < 0)
                         goto out;
                 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
         } else if (S_ISCHR(mode) || S_ISBLK(mode) ||
                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
-                TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, btrfs_inode_rdev(eb, ii));
+                TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, rdev);
         }
 
         ret = send_cmd(sctx);
@@ -2368,6 +2367,92 @@ out:
         return ret;
 }
 
+/*
+ * We need some special handling for inodes that get processed before the parent
+ * directory got created. See process_recorded_refs for details.
+ * This function does the check if we already created the dir out of order.
+ */
+static int did_create_dir(struct send_ctx *sctx, u64 dir)
+{
+        int ret = 0;
+        struct btrfs_path *path = NULL;
+        struct btrfs_key key;
+        struct btrfs_key found_key;
+        struct btrfs_key di_key;
+        struct extent_buffer *eb;
+        struct btrfs_dir_item *di;
+        int slot;
+
+        path = alloc_path_for_send();
+        if (!path) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        key.objectid = dir;
+        key.type = BTRFS_DIR_INDEX_KEY;
+        key.offset = 0;
+        while (1) {
+                ret = btrfs_search_slot_for_read(sctx->send_root, &key, path,
+                                1, 0);
+                if (ret < 0)
+                        goto out;
+                if (!ret) {
+                        eb = path->nodes[0];
+                        slot = path->slots[0];
+                        btrfs_item_key_to_cpu(eb, &found_key, slot);
+                }
+                if (ret || found_key.objectid != key.objectid ||
+                    found_key.type != key.type) {
+                        ret = 0;
+                        goto out;
+                }
+
+                di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
+                btrfs_dir_item_key_to_cpu(eb, di, &di_key);
+
+                if (di_key.objectid < sctx->send_progress) {
+                        ret = 1;
+                        goto out;
+                }
+
+                key.offset = found_key.offset + 1;
+                btrfs_release_path(path);
+        }
+
+out:
+        btrfs_free_path(path);
+        return ret;
+}
+
+/*
+ * Only creates the inode if it is:
+ * 1. Not a directory
+ * 2. Or a directory which was not created already due to out of order
+ *    directories. See did_create_dir and process_recorded_refs for details.
+ */
+static int send_create_inode_if_needed(struct send_ctx *sctx)
+{
+        int ret;
+
+        if (S_ISDIR(sctx->cur_inode_mode)) {
+                ret = did_create_dir(sctx, sctx->cur_ino);
+                if (ret < 0)
+                        goto out;
+                if (ret) {
+                        ret = 0;
+                        goto out;
+                }
+        }
+
+        ret = send_create_inode(sctx, sctx->cur_ino);
+        if (ret < 0)
+                goto out;
+
+out:
+        return ret;
+}
+
 struct recorded_ref {
         struct list_head list;
         char *dir_path;
@@ -2517,160 +2602,6 @@ out:
         return ret;
 }
 
-struct finish_unordered_dir_ctx {
-        struct send_ctx *sctx;
-        struct fs_path *cur_path;
-        struct fs_path *dir_path;
-        u64 dir_ino;
-        int need_delete;
-        int delete_pass;
-};
-
-int __finish_unordered_dir(int num, struct btrfs_key *di_key,
-                           const char *name, int name_len,
-                           const char *data, int data_len,
-                           u8 type, void *ctx)
-{
-        int ret = 0;
-        struct finish_unordered_dir_ctx *fctx = ctx;
-        struct send_ctx *sctx = fctx->sctx;
-        u64 di_gen;
-        u64 di_mode;
-        int is_orphan = 0;
-
-        if (di_key->objectid >= fctx->dir_ino)
-                goto out;
-
-        fs_path_reset(fctx->cur_path);
-
-        ret = get_inode_info(sctx->send_root, di_key->objectid,
-                        NULL, &di_gen, &di_mode, NULL, NULL, NULL);
-        if (ret < 0)
-                goto out;
-
-        ret = is_first_ref(sctx, sctx->send_root, di_key->objectid,
-                        fctx->dir_ino, name, name_len);
-        if (ret < 0)
-                goto out;
-        if (ret) {
-                is_orphan = 1;
-                ret = gen_unique_name(sctx, di_key->objectid, di_gen,
-                                fctx->cur_path);
-        } else {
-                ret = get_cur_path(sctx, di_key->objectid, di_gen,
-                                fctx->cur_path);
-        }
-        if (ret < 0)
-                goto out;
-
-        ret = fs_path_add(fctx->dir_path, name, name_len);
-        if (ret < 0)
-                goto out;
-
-        if (!fctx->delete_pass) {
-                if (S_ISDIR(di_mode)) {
-                        ret = send_rename(sctx, fctx->cur_path,
-                                        fctx->dir_path);
-                } else {
-                        ret = send_link(sctx, fctx->dir_path,
-                                        fctx->cur_path);
-                        if (is_orphan)
-                                fctx->need_delete = 1;
-                }
-        } else if (!S_ISDIR(di_mode)) {
-                ret = send_unlink(sctx, fctx->cur_path);
-        } else {
-                ret = 0;
-        }
-
-        fs_path_remove(fctx->dir_path);
-
-out:
-        return ret;
-}
-
-/*
- * Go through all dir items and see if we find refs which could not be created
- * in the past because the dir did not exist at that time.
- */
-static int finish_outoforder_dir(struct send_ctx *sctx, u64 dir, u64 dir_gen)
-{
-        int ret = 0;
-        struct btrfs_path *path = NULL;
-        struct btrfs_key key;
-        struct btrfs_key found_key;
-        struct extent_buffer *eb;
-        struct finish_unordered_dir_ctx fctx;
-        int slot;
-
-        path = alloc_path_for_send();
-        if (!path) {
-                ret = -ENOMEM;
-                goto out;
-        }
-
-        memset(&fctx, 0, sizeof(fctx));
-        fctx.sctx = sctx;
-        fctx.cur_path = fs_path_alloc(sctx);
-        fctx.dir_path = fs_path_alloc(sctx);
-        if (!fctx.cur_path || !fctx.dir_path) {
-                ret = -ENOMEM;
-                goto out;
-        }
-        fctx.dir_ino = dir;
-
-        ret = get_cur_path(sctx, dir, dir_gen, fctx.dir_path);
-        if (ret < 0)
-                goto out;
-
-        /*
-         * We do two passes. The first links in the new refs and the second
-         * deletes orphans if required. Deletion of orphans is not required for
-         * directory inodes, as we always have only one ref and use rename
-         * instead of link for those.
-         */
-
-again:
-        key.objectid = dir;
-        key.type = BTRFS_DIR_ITEM_KEY;
-        key.offset = 0;
-        while (1) {
-                ret = btrfs_search_slot_for_read(sctx->send_root, &key, path,
-                                1, 0);
-                if (ret < 0)
-                        goto out;
-                eb = path->nodes[0];
-                slot = path->slots[0];
-                btrfs_item_key_to_cpu(eb, &found_key, slot);
-
-                if (found_key.objectid != key.objectid ||
-                    found_key.type != key.type) {
-                        btrfs_release_path(path);
-                        break;
-                }
-
-                ret = iterate_dir_item(sctx, sctx->send_root, path,
-                                &found_key, __finish_unordered_dir,
-                                &fctx);
-                if (ret < 0)
-                        goto out;
-
-                key.offset = found_key.offset + 1;
-                btrfs_release_path(path);
-        }
-
-        if (!fctx.delete_pass && fctx.need_delete) {
-                fctx.delete_pass = 1;
-                goto again;
-        }
-
-out:
-        btrfs_free_path(path);
-        fs_path_free(sctx, fctx.cur_path);
-        fs_path_free(sctx, fctx.dir_path);
-        return ret;
-}
-
 /*
  * This does all the move/link/unlink/rmdir magic.
  */
@@ -2678,6 +2609,7 @@ static int process_recorded_refs(struct send_ctx *sctx)
 {
         int ret = 0;
         struct recorded_ref *cur;
+        struct recorded_ref *cur2;
         struct ulist *check_dirs = NULL;
         struct ulist_iterator uit;
         struct ulist_node *un;
@@ -2735,6 +2667,46 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
 
         list_for_each_entry(cur, &sctx->new_refs, list) {
                 /*
+                 * We may have refs where the parent directory does not exist
+                 * yet. This happens if the parent directories inum is higher
+                 * the the current inum. To handle this case, we create the
+                 * parent directory out of order. But we need to check if this
+                 * did already happen before due to other refs in the same dir.
+                 */
+                ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
+                if (ret < 0)
+                        goto out;
+                if (ret == inode_state_will_create) {
+                        ret = 0;
+                        /*
+                         * First check if any of the current inodes refs did
+                         * already create the dir.
+                         */
+                        list_for_each_entry(cur2, &sctx->new_refs, list) {
+                                if (cur == cur2)
+                                        break;
+                                if (cur2->dir == cur->dir) {
+                                        ret = 1;
+                                        break;
+                                }
+                        }
+
+                        /*
+                         * If that did not happen, check if a previous inode
+                         * did already create the dir.
+                         */
+                        if (!ret)
+                                ret = did_create_dir(sctx, cur->dir);
+                        if (ret < 0)
+                                goto out;
+                        if (!ret) {
+                                ret = send_create_inode(sctx, cur->dir);
+                                if (ret < 0)
+                                        goto out;
+                        }
+                }
+
+                /*
                  * Check if this new ref would overwrite the first ref of
                  * another unprocessed inode. If yes, orphanize the
                  * overwritten inode. If we find an overwritten ref that is
@@ -2768,7 +2740,7 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
                  * inode, move it and update valid_path. If not, link or move
                  * it depending on the inode mode.
                  */
-                if (is_orphan && !sctx->cur_inode_first_ref_orphan) {
+                if (is_orphan) {
                         ret = send_rename(sctx, valid_path, cur->full_path);
                         if (ret < 0)
                                 goto out;
@@ -2844,35 +2816,9 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
                         if (ret < 0)
                                 goto out;
                         if (!ret) {
-                                /*
-                                 * In case the inode was moved to a directory
-                                 * that was not created yet (see
-                                 * __record_new_ref), we can not unlink the ref
-                                 * as it will be needed later when the parent
-                                 * directory is created, so that we can move in
-                                 * the inode to the new dir.
-                                 */
-                                if (!is_orphan &&
-                                    sctx->cur_inode_first_ref_orphan) {
-                                        ret = orphanize_inode(sctx,
-                                                        sctx->cur_ino,
-                                                        sctx->cur_inode_gen,
-                                                        cur->full_path);
-                                        if (ret < 0)
-                                                goto out;
-                                        ret = gen_unique_name(sctx,
-                                                        sctx->cur_ino,
-                                                        sctx->cur_inode_gen,
-                                                        valid_path);
-                                        if (ret < 0)
-                                                goto out;
-                                        is_orphan = 1;
-
-                                } else {
-                                        ret = send_unlink(sctx, cur->full_path);
-                                        if (ret < 0)
-                                                goto out;
-                                }
+                                ret = send_unlink(sctx, cur->full_path);
+                                if (ret < 0)
+                                        goto out;
                         }
                         ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
                                         GFP_NOFS);
@@ -2885,11 +2831,8 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
                  * happen when a previous inode did overwrite the first ref
                  * of this inode and no new refs were added for the current
                  * inode.
-                 * We can however not delete the orphan in case the inode relies
-                 * in a directory that was not created yet (see
-                 * __record_new_ref)
                  */
-                if (is_orphan && !sctx->cur_inode_first_ref_orphan) {
+                if (is_orphan) {
                         ret = send_unlink(sctx, valid_path);
                         if (ret < 0)
                                 goto out;
@@ -2939,19 +2882,6 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
          */
         sctx->send_progress = sctx->cur_ino + 1;
 
-        /*
-         * We may have a directory here that has pending refs which could not
-         * be created before (because the dir did not exist before, see
-         * __record_new_ref). finish_outoforder_dir will link/move the pending
-         * refs.
-         */
-        if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_new) {
-                ret = finish_outoforder_dir(sctx, sctx->cur_ino,
-                                sctx->cur_inode_gen);
-                if (ret < 0)
-                        goto out;
-        }
-
         ret = 0;
 
 out:
@@ -2979,31 +2909,6 @@ static int __record_new_ref(int num, u64 dir, int index,
         if (ret < 0)
                 goto out;
 
-        /*
-         * The parent may be non-existent at this point in time. This happens
-         * if the ino of the parent dir is higher then the current ino. In this
-         * case, we can not process this ref until the parent dir is finally
-         * created. If we reach the parent dir later, process_recorded_refs
-         * will go through all dir items and process the refs that could not be
-         * processed before. In case this is the first ref, we set
-         * cur_inode_first_ref_orphan to 1 to inform process_recorded_refs to
-         * keep an orphan of the inode so that it later can be used for
-         * link/move
-         */
-        ret = is_inode_existent(sctx, dir, gen);
-        if (ret < 0)
-                goto out;
-        if (!ret) {
-                ret = is_first_ref(sctx, sctx->send_root, sctx->cur_ino, dir,
-                                name->start, fs_path_len(name));
-                if (ret < 0)
-                        goto out;
-                if (ret)
-                        sctx->cur_inode_first_ref_orphan = 1;
-                ret = 0;
-                goto out;
-        }
-
         ret = get_cur_path(sctx, dir, gen, p);
         if (ret < 0)
                 goto out;
@@ -4078,7 +3983,6 @@ static int changed_inode(struct send_ctx *sctx,
 
         sctx->cur_ino = key->objectid;
         sctx->cur_inode_new_gen = 0;
-        sctx->cur_inode_first_ref_orphan = 0;
         sctx->send_progress = sctx->cur_ino;
 
         if (result == BTRFS_COMPARE_TREE_NEW ||
@@ -4115,8 +4019,7 @@ static int changed_inode(struct send_ctx *sctx,
                 sctx->cur_inode_mode = btrfs_inode_mode(
                                 sctx->left_path->nodes[0], left_ii);
                 if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
-                        ret = send_create_inode(sctx, sctx->left_path,
-                                        sctx->cmp_key);
+                        ret = send_create_inode_if_needed(sctx);
         } else if (result == BTRFS_COMPARE_TREE_DELETED) {
                 sctx->cur_inode_gen = right_gen;
                 sctx->cur_inode_new = 0;
@@ -4146,8 +4049,7 @@ static int changed_inode(struct send_ctx *sctx,
                                         sctx->left_path->nodes[0], left_ii);
                         sctx->cur_inode_mode = btrfs_inode_mode(
                                         sctx->left_path->nodes[0], left_ii);
-                        ret = send_create_inode(sctx, sctx->left_path,
-                                        sctx->cmp_key);
+                        ret = send_create_inode_if_needed(sctx);
                         if (ret < 0)
                                 goto out;