[PATCH 4/6] btrfs-progs: Add btrfs_unlink() and btrfs_add_link() functions.

[PATCH 4/6] btrfs-progs: Add btrfs_unlink() and btrfs_add_link() functions.

[Qu Wenruo]

Add btrfs_unlink() and btrfs_add_link() functions in inode.c,
for the incoming btrfs_mkdir() and later inode operations functions.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
Changlog:
v2:
   Do dir name conflicting check before adding inode_backref or
   dir_item/index.
---
 Makefile     |   2 +-
 cmds-check.c |   7 +-
 ctree.h      |  12 ++
 inode.c      | 376 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 390 insertions(+), 7 deletions(-)
 create mode 100644 inode.c

diff --git a/Makefile b/Makefile
index 4cae30c..d7a5cbe 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
 	  root-tree.o dir-item.o file-item.o inode-item.o inode-map.o \
 	  extent-cache.o extent_io.o volumes.o utils.o repair.o \
 	  qgroup.o raid6.o free-space-cache.o list_sort.o props.o \
-	  ulist.o qgroup-verify.o backref.o
+	  ulist.o qgroup-verify.o backref.o inode.o
 cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
 	       cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
 	       cmds-quota.o cmds-qgroup.o cmds-replace.o cmds-check.o \
diff --git a/cmds-check.c b/cmds-check.c
index 9fc1410..6419caf 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -1599,14 +1599,9 @@ static int repair_inode_orphan_item(struct btrfs_trans_handle *trans,
 				    struct btrfs_path *path,
 				    struct inode_record *rec)
 {
-	struct btrfs_key key;
 	int ret;
 
-	key.objectid = BTRFS_ORPHAN_OBJECTID;
-	key.type = BTRFS_ORPHAN_ITEM_KEY;
-	key.offset = rec->ino;
-
-	ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
+	ret = btrfs_add_orphan_item(trans, root, path, rec->ino);
 	btrfs_release_path(path);
 	if (!ret)
 		rec->errors &= ~I_ERR_NO_ORPHAN_ITEM;
diff --git a/ctree.h b/ctree.h
index 32b1286..17b3b20 100644
--- a/ctree.h
+++ b/ctree.h
@@ -2444,4 +2444,16 @@ static inline int is_fstree(u64 rootid)
 		return 1;
 	return 0;
 }
+
+/* inode.c */
+int btrfs_add_link(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		   u64 ino, u64 parent_ino, char *name, int namelen,
+		   u8 type, u64 *index, int add_backref);
+int btrfs_unlink(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		 u64 ino, u64 parent_ino, u64 index, const char *name,
+		 int namelen, int add_orphan);
+int btrfs_add_orphan_item(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root,
+			  struct btrfs_path *path,
+			  u64 ino);
 #endif
diff --git a/inode.c b/inode.c
new file mode 100644
index 0000000..f085d30
--- /dev/null
+++ b/inode.c
@@ -0,0 +1,376 @@
+/*
+ * Copyright (C) 2014 Fujitsu.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+/*
+ * Unlike inode.c in kernel, which can use most of the kernel infrastructure
+ * like inode/dentry things, in user-land, we can only use inode number to
+ * do directly operation on extent buffer, which may cause extra searching,
+ * but should not be a huge problem since progs is less performence sensitive.
+ */
+#include <sys/stat.h>
+#include "ctree.h"
+#include "transaction.h"
+#include "disk-io.h"
+#include "time.h"
+
+/*
+ * Find a free inode index for later btrfs_add_link().
+ * Currently just search from the largest dir_index and +1.
+ */
+static int btrfs_find_free_dir_index(struct btrfs_root *root, u64 dir_ino,
+				     u64 *ret_ino)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_key found_key;
+	u64 ret_val = 2;
+	int ret = 0;
+
+	if (!ret_ino)
+		return 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	key.objectid = dir_ino;
+	key.type = BTRFS_DIR_INDEX_KEY;
+	key.offset = (u64)-1;
+
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+	ret = 0;
+	if (path->slots[0] == 0) {
+		ret = btrfs_prev_leaf(root, path);
+		if (ret < 0)
+			goto out;
+		if (ret > 0) {
+			/*
+			 * This shouldn't happen since there must be a leaf
+			 * containing the DIR_ITEM.
+			 * Can only happen when the previous leaf is corrupted.
+			 */
+			ret = -EIO;
+			goto out;
+		}
+	} else {
+		path->slots[0]--;
+	}
+	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
+	if (found_key.objectid != dir_ino ||
+	    found_key.type != BTRFS_DIR_INDEX_KEY)
+		goto out;
+	ret_val = found_key.offset + 1;
+out:
+	btrfs_free_path(path);
+	if (ret == 0)
+		*ret_ino = ret_val;
+	return ret;
+}
+
+/*
+ * Add dir_item/index for 'parent_ino'
+ * if add_backref is true, also insert a backref from the ino to parent dir
+ * and update the nlink(Kernel version does not do this thing)
+ *
+ * Currently only supports adding link from an inode to another inode.
+ */
+int btrfs_add_link(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		   u64 ino, u64 parent_ino, char *name, int namelen,
+		   u8 type, u64 *index, int add_backref)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_dir_item *dir_item;
+	u32 nlink;
+	u64 inode_size;
+	u64 ret_index = 0;
+	int ret = 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	/*
+	 * Check name conflict, index won't conflict.
+	 */
+	dir_item = btrfs_lookup_dir_item(NULL, root, path, parent_ino,
+					 name, namelen, 0);
+	if (IS_ERR(dir_item)) {
+		ret = PTR_ERR(dir_item);
+		goto out;
+	}
+	if (dir_item) {
+		ret = -EEXIST;
+		goto out;
+	}
+	btrfs_release_path(path);
+
+	ret = btrfs_find_free_dir_index(root, parent_ino, &ret_index);
+	if (ret < 0)
+		goto out;
+
+	/* Add inode ref */
+	if (add_backref) {
+		ret = btrfs_insert_inode_ref(trans, root, name, namelen,
+					     ino, parent_ino, ret_index);
+		if (ret < 0)
+			goto out;
+
+		/* Update nlinks for the inode */
+		key.objectid = ino;
+		key.type = BTRFS_INODE_ITEM_KEY;
+		key.offset = 0;
+		ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
+		if (ret) {
+			if (ret > 0)
+				ret = -ENOENT;
+			goto out;
+		}
+		inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				    struct btrfs_inode_item);
+		nlink = btrfs_inode_nlink(path->nodes[0], inode_item);
+		nlink++;
+		btrfs_set_inode_nlink(path->nodes[0], inode_item, nlink);
+		btrfs_mark_buffer_dirty(path->nodes[0]);
+		btrfs_release_path(path);
+	}
+
+	/* Add dir_item and dir_index */
+	key.objectid = ino;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+	ret = btrfs_insert_dir_item(trans, root, name, namelen, parent_ino,
+				    &key, type, ret_index);
+	if (ret < 0)
+		goto out;
+
+	/* Update inode size of the parent inode */
+	key.objectid = parent_ino;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+	ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
+	if (ret)
+		goto out;
+	inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				    struct btrfs_inode_item);
+	inode_size = btrfs_inode_size(path->nodes[0], inode_item);
+	inode_size += namelen * 2;
+	btrfs_set_inode_size(path->nodes[0], inode_item, inode_size);
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+	btrfs_release_path(path);
+
+out:
+	btrfs_free_path(path);
+	if (ret == 0 && index)
+		*index = ret_index;
+	return ret;
+}
+
+int btrfs_add_orphan_item(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root,
+			  struct btrfs_path *path,
+			  u64 ino)
+{
+	struct btrfs_key key;
+	int ret = 0;
+
+	key.objectid = BTRFS_ORPHAN_OBJECTID;
+	key.type = BTRFS_ORPHAN_ITEM_KEY;
+	key.offset = ino;
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
+	return ret;
+}
+
+/*
+ * Unlink an inode, which will remove its backref and corresponding dir_index/
+ * dir_item if any of them exists.
+ *
+ * If an inode's nlink is reduced to 0 and 'add_orphan' is true, it will be
+ * added to orphan inode and wairing to be deleted by next kernel mount.
+ */
+int btrfs_unlink(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		 u64 ino, u64 parent_ino, u64 index, const char *name,
+		 int namelen, int add_orphan)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_inode_ref *inode_ref;
+	struct btrfs_dir_item *dir_item;
+	u64 inode_size;
+	u32 nlinks;
+	int del_inode_ref = 0;
+	int del_dir_item = 0;
+	int del_dir_index = 0;
+	int ret = 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	/* check the ref and backref exists */
+	inode_ref = btrfs_lookup_inode_ref(trans, root, path, name, namelen,
+					   ino, parent_ino, index, 0);
+	if (IS_ERR(inode_ref)) {
+		ret = PTR_ERR(inode_ref);
+		goto out;
+	}
+	if (inode_ref)
+		del_inode_ref = 1;
+	btrfs_release_path(path);
+
+	dir_item = btrfs_lookup_dir_item(NULL, root, path, parent_ino,
+					 name, namelen, 0);
+	if (IS_ERR(dir_item)) {
+		ret = PTR_ERR(dir_item);
+		goto out;
+	}
+	if (dir_item)
+		del_dir_item = 1;
+	btrfs_release_path(path);
+
+	dir_item = btrfs_lookup_dir_index(NULL, root, path, parent_ino,
+					  name, namelen, index, 0);
+	/*
+	 * Since lookup_dir_index() will return -ENOENT when not found,
+	 * we need to do extra check.
+	 */
+	if (IS_ERR(dir_item) && PTR_ERR(dir_item) == -ENOENT)
+		dir_item = NULL;
+	if (IS_ERR(dir_item)) {
+		ret = PTR_ERR(dir_item);
+		goto out;
+	}
+	if (dir_item)
+		del_dir_index = 1;
+	btrfs_release_path(path);
+
+	if (!del_inode_ref && !del_dir_item && !del_dir_index) {
+		/* All not found, shouldn't happen */
+		ret = -ENOENT;
+		goto out;
+	}
+
+	if (del_inode_ref) {
+		/* Only decrease nlink when deleting inode_ref */
+		key.objectid = ino;
+		key.type = BTRFS_INODE_ITEM_KEY;
+		key.offset = 0;
+		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+		if (ret) {
+			if (ret > 0)
+				ret = -ENOENT;
+			goto out;
+		}
+		inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+					    struct btrfs_inode_item);
+		nlinks = btrfs_inode_nlink(path->nodes[0], inode_item);
+		if (nlinks > 0)
+			nlinks--;
+		btrfs_set_inode_nlink(path->nodes[0], inode_item, nlinks);
+		btrfs_mark_buffer_dirty(path->nodes[0]);
+		btrfs_release_path(path);
+
+		/* For nlinks == 0, add it to orphan list if needed */
+		if (nlinks == 0 && add_orphan) {
+			ret = btrfs_add_orphan_item(trans, root, path, ino);
+			btrfs_mark_buffer_dirty(path->nodes[0]);
+			btrfs_release_path(path);
+		}
+
+		ret = btrfs_del_inode_ref(trans, root, name, namelen, ino,
+					  parent_ino, &index);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (del_dir_index) {
+		dir_item = btrfs_lookup_dir_index(trans, root, path,
+						  parent_ino, name, namelen,
+						  index, -1);
+		if (IS_ERR(dir_item)) {
+			ret = PTR_ERR(dir_item);
+			goto out;
+		}
+		if (!dir_item) {
+			ret = -ENOENT;
+			goto out;
+		}
+		ret = btrfs_delete_one_dir_name(trans, root, path, dir_item);
+		if (ret)
+			goto out;
+		btrfs_release_path(path);
+
+		/* Update inode size of the parent inode */
+		key.objectid = parent_ino;
+		key.type = BTRFS_INODE_ITEM_KEY;
+		key.offset = 0;
+		ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
+		if (ret)
+			goto out;
+		inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+					    struct btrfs_inode_item);
+		inode_size = btrfs_inode_size(path->nodes[0], inode_item);
+		if (inode_size >= namelen)
+			inode_size -= namelen;
+		btrfs_set_inode_size(path->nodes[0], inode_item, inode_size);
+		btrfs_mark_buffer_dirty(path->nodes[0]);
+		btrfs_release_path(path);
+	}
+
+	if (del_dir_item) {
+		dir_item = btrfs_lookup_dir_item(trans, root, path, parent_ino,
+						 name, namelen, -1);
+		if (IS_ERR(dir_item)) {
+			ret = PTR_ERR(dir_item);
+			goto out;
+		}
+		if (!dir_item) {
+			ret = -ENOENT;
+			goto out;
+		}
+		ret = btrfs_delete_one_dir_name(trans, root, path, dir_item);
+		if (ret < 0)
+			goto out;
+		btrfs_release_path(path);
+
+		/* Update inode size of the parent inode */
+		key.objectid = parent_ino;
+		key.type = BTRFS_INODE_ITEM_KEY;
+		key.offset = 0;
+		ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
+		if (ret)
+			goto out;
+		inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+					    struct btrfs_inode_item);
+		inode_size = btrfs_inode_size(path->nodes[0], inode_item);
+		if (inode_size >= namelen)
+			inode_size -= namelen;
+		btrfs_set_inode_size(path->nodes[0], inode_item, inode_size);
+		btrfs_mark_buffer_dirty(path->nodes[0]);
+		btrfs_release_path(path);
+	}
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}
-- 
2.1.3

[PATCH 5/6] btrfs-progs: Add btrfs_mkdir() function for the incoming 'lost+found' fsck mechanism.

[Qu Wenruo]

With the previous btrfs inode operations patches, now we can use
btrfs_mkdir() to create the 'lost+found' dir to do some data salvage in
btrfsck.

This patch along with previous ones will make data salvage easier.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
Changlog:
v2:
   Fix a bug that returns the parent ino other than the existing dir
   ino.
---
 ctree.h |  2 ++
 inode.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+)

diff --git a/ctree.h b/ctree.h
index 17b3b20..ec969ab 100644
--- a/ctree.h
+++ b/ctree.h
@@ -2456,4 +2456,6 @@ int btrfs_add_orphan_item(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  struct btrfs_path *path,
 			  u64 ino);
+int btrfs_mkdir(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		char *name, int namelen, u64 parent_ino, u64 *ino, int mode);
 #endif
diff --git a/inode.c b/inode.c
index f085d30..e738cb8 100644
--- a/inode.c
+++ b/inode.c
@@ -374,3 +374,95 @@ out:
 	btrfs_free_path(path);
 	return ret;
 }
+
+/* Fill inode item with 'mode'. Uid/gid to root/root */
+static void fill_inode_item(struct btrfs_trans_handle *trans,
+			    struct btrfs_inode_item *inode_item,
+			    u32 mode, u32 nlink)
+{
+	time_t now = time(NULL);
+
+	btrfs_set_stack_inode_generation(inode_item, trans->transid);
+	btrfs_set_stack_inode_uid(inode_item, 0);
+	btrfs_set_stack_inode_gid(inode_item, 0);
+	btrfs_set_stack_inode_size(inode_item, 0);
+	btrfs_set_stack_inode_mode(inode_item, mode);
+	btrfs_set_stack_inode_nlink(inode_item, nlink);
+	btrfs_set_stack_timespec_sec(&inode_item->atime, now);
+	btrfs_set_stack_timespec_nsec(&inode_item->atime, 0);
+	btrfs_set_stack_timespec_sec(&inode_item->mtime, now);
+	btrfs_set_stack_timespec_nsec(&inode_item->mtime, 0);
+	btrfs_set_stack_timespec_sec(&inode_item->ctime, now);
+	btrfs_set_stack_timespec_nsec(&inode_item->ctime, 0);
+}
+
+/*
+ * Unlike kernel btrfs_new_inode(), we only create the INODE_ITEM, without
+ * its backref.
+ * The backref is added by btrfs_add_link().
+ */
+static int btrfs_new_inode(struct btrfs_trans_handle *trans,
+			   struct btrfs_root *root,
+			   u64 ino, u32 mode)
+{
+	struct btrfs_inode_item inode_item = {0};
+	int ret = 0;
+
+	fill_inode_item(trans, &inode_item, mode, 0);
+	ret = btrfs_insert_inode(trans, root, ino, &inode_item);
+	return ret;
+}
+
+/*
+ * Make a dir under the parent inode 'parent_ino' with 'name'
+ * and 'mode', The owner will be root/root.
+ */
+int btrfs_mkdir(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		char *name, int namelen, u64 parent_ino, u64 *ino, int mode)
+{
+	struct btrfs_dir_item *dir_item;
+	struct btrfs_path *path;
+	u64 ret_ino;
+	int ret = 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	dir_item = btrfs_lookup_dir_item(NULL, root, path, parent_ino,
+					 name, namelen, 0);
+	if (IS_ERR(dir_item)) {
+		ret = PTR_ERR(dir_item);
+		goto out;
+	}
+
+	if (dir_item) {
+		struct btrfs_key found_key;
+
+		/*
+		 * Already have conflicting name, check if it is a dir.
+		 * Either way, no need to continue.
+		 */
+		btrfs_dir_item_key_to_cpu(path->nodes[0], dir_item, &found_key);
+		ret_ino = found_key.objectid;
+		if (btrfs_dir_type(path->nodes[0], dir_item) != BTRFS_FT_DIR)
+			ret = -EEXIST;
+		goto out;
+	}
+
+	ret = btrfs_find_free_objectid(NULL, root, parent_ino, &ret_ino);
+	if (ret)
+		goto out;
+	ret = btrfs_new_inode(trans, root, ret_ino, mode | S_IFDIR);
+	if (ret)
+		goto out;
+	ret = btrfs_add_link(trans, root, ret_ino, parent_ino, name, namelen,
+			     BTRFS_FT_DIR, NULL, 1);
+	if (ret)
+		goto out;
+out:
+	btrfs_free_path(path);
+	if (ret == 0 && ino)
+		*ino = ret_ino;
+	return ret;
+}
-- 
2.1.3

[PATCH 0/6] btrfs-progs: New 'lost+found' infrastructrue with

[Qu Wenruo]

[SUMMARY]
Introduce the new 'lost+found' dir and related infrastructure to create it
in btrfs-progs.

[BUG]
With the new infrastructure, fix a bug that some people reported in both
kernel BZ and maillist, which there is some files' nlink is 1 but backref
points to non-exist parent.
The two reporters all report missing file(chrome config file), so we'd
better not to delete such files but use the 'lost+found' dir.

This bug is a kernel bug needing to be investigated, but the progs fix is
here before kernel fix.

[ROADMAP]
1. Fix the leaf corruption.
Currently, btrfs-progs can ignore corrupt leaf and continue
checking/reparing, however in that case, most problem can't be recovered
since its parent is missing(in corrupted leaf) and we were not able to
move them to someplace due to the missing of 'lost+found' dir.

With this patchset, there is a hope to fix such problems and I will
continue such work until we can fix most of most of the fs.

2. Unify the repair framework.
When writing the 6th patch, I think it is better to build a frame work
that unify the check and repair framework.
In 6th patch, my patchset and Josef's commit 2dc4c001 in fact has some
similar function but do the repair in different time and functions.

I will try to build a unified framework for repair, each repair will be
independent and have its own err number.
And each repair function should work like the following:
1) Check the error number
2) Do the repair
3) Update the related btrfsck record(like newly created inode, deleted inode)

Qu Wenruo (6):
  btrfs-progs: print root dir verbose error in fsck
  btrfs-progs: Import btrfs_insert/del/lookup_extref() functions.
  btrfs-progs: Import lookup/del_inode_ref() function.
  btrfs-progs: Add btrfs_unlink() and btrfs_add_link() functions.
  btrfs-progs: Add btrfs_mkdir() function for the incoming 'lost+found' 
       fsck mechanism.
  btrfs-progs: Add fixing function for inodes whose nlink dismatch

 Makefile     |   2 +-
 cmds-check.c | 284 +++++++++++++++++++++++++++++++++++--
 ctree.c      |   6 +
 ctree.h      |  38 +++++
 inode-item.c | 318 +++++++++++++++++++++++++++++++++++++++++
 inode.c      | 453 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 1090 insertions(+), 11 deletions(-)
 create mode 100644 inode.c

-- 
2.1.3

[PATCH 5/6] btrfs-progs: Add btrfs_mkdir() function for the incoming 'lost+found' fsck mechanism.

[Qu Wenruo]

With the previous btrfs inode operations patches, now we can use
btrfs_mkdir() to create the 'lost+found' dir to do some data salvage in
btrfsck.

This patch along with previous ones will make data salvage easier.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 ctree.h |  2 ++
 inode.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+)

diff --git a/ctree.h b/ctree.h
index 17b3b20..ec969ab 100644
--- a/ctree.h
+++ b/ctree.h
@@ -2456,4 +2456,6 @@ int btrfs_add_orphan_item(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  struct btrfs_path *path,
 			  u64 ino);
+int btrfs_mkdir(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		char *name, int namelen, u64 parent_ino, u64 *ino, int mode);
 #endif
diff --git a/inode.c b/inode.c
index 7305e58..03dece7 100644
--- a/inode.c
+++ b/inode.c
@@ -359,3 +359,95 @@ out:
 	btrfs_free_path(path);
 	return ret;
 }
+
+/* Fill inode item with 'mode'. Uid/gid to root/root */
+static void fill_inode_item(struct btrfs_trans_handle *trans,
+			    struct btrfs_inode_item *inode_item,
+			    u32 mode, u32 nlink)
+{
+	time_t now = time(NULL);
+
+	btrfs_set_stack_inode_generation(inode_item, trans->transid);
+	btrfs_set_stack_inode_uid(inode_item, 0);
+	btrfs_set_stack_inode_gid(inode_item, 0);
+	btrfs_set_stack_inode_size(inode_item, 0);
+	btrfs_set_stack_inode_mode(inode_item, mode);
+	btrfs_set_stack_inode_nlink(inode_item, nlink);
+	btrfs_set_stack_timespec_sec(&inode_item->atime, now);
+	btrfs_set_stack_timespec_nsec(&inode_item->atime, 0);
+	btrfs_set_stack_timespec_sec(&inode_item->mtime, now);
+	btrfs_set_stack_timespec_nsec(&inode_item->mtime, 0);
+	btrfs_set_stack_timespec_sec(&inode_item->ctime, now);
+	btrfs_set_stack_timespec_nsec(&inode_item->ctime, 0);
+}
+
+/*
+ * Unlike kernel btrfs_new_inode(), we only create the INODE_ITEM, without
+ * its backref.
+ * The backref is added by btrfs_add_link().
+ */
+static int btrfs_new_inode(struct btrfs_trans_handle *trans,
+			   struct btrfs_root *root,
+			   u64 ino, u32 mode)
+{
+	struct btrfs_inode_item inode_item = {0};
+	int ret = 0;
+
+	fill_inode_item(trans, &inode_item, mode, 0);
+	ret = btrfs_insert_inode(trans, root, ino, &inode_item);
+	return ret;
+}
+
+/*
+ * Make a dir under the parent inode 'parent_ino' with 'name'
+ * and 'mode', The owner will be root/root.
+ */
+int btrfs_mkdir(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		char *name, int namelen, u64 parent_ino, u64 *ino, int mode)
+{
+	struct btrfs_dir_item *dir_item;
+	struct btrfs_path *path;
+	u64 ret_ino;
+	int ret = 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	dir_item = btrfs_lookup_dir_item(NULL, root, path, parent_ino,
+					 name, namelen, 0);
+	if (IS_ERR(dir_item)) {
+		ret = PTR_ERR(dir_item);
+		goto out;
+	}
+
+	if (dir_item) {
+		struct btrfs_key found_key;
+
+		/*
+		 * Already have conflicting name, check if it is a dir.
+		 * Either way, no need to continue.
+		 */
+		btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
+		ret_ino = found_key.objectid;
+		if (btrfs_dir_type(path->nodes[0], dir_item) != BTRFS_FT_DIR)
+			ret = -EEXIST;
+		goto out;
+	}
+
+	ret = btrfs_find_free_objectid(NULL, root, parent_ino, &ret_ino);
+	if (ret)
+		goto out;
+	ret = btrfs_new_inode(trans, root, ret_ino, mode | S_IFDIR);
+	if (ret)
+		goto out;
+	ret = btrfs_add_link(trans, root, ret_ino, parent_ino, name, namelen,
+			     BTRFS_FT_DIR, NULL, 1);
+	if (ret)
+		goto out;
+out:
+	btrfs_free_path(path);
+	if (ret == 0 && ino)
+		*ino = ret_ino;
+	return ret;
+}
-- 
2.1.3