Introduce a function, find_file_type(), to find filetype using
INODE_REF.

This function will:
- Search DIR_INDEX first
  DIR_INDEX is easier since there is only one item in it.

- Valid the DIR_INDEX item
  If the DIR_INDEX is valid, use the filetype and call it a day.

- Search DIR_ITEM then

- Valide the DIR_ITEM
  If valid, call it a day. Or return -ENOENT;

This would be used as the primary method to determine the imode in later
imode repair code.

Signed-off-by: Qu Wenruo <w...@suse.com>
---
 check/mode-common.c | 99 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/check/mode-common.c b/check/mode-common.c
index 195b6efaa7aa..c0ddc50a1dd0 100644
--- a/check/mode-common.c
+++ b/check/mode-common.c
@@ -16,6 +16,7 @@
 
 #include <time.h>
 #include "ctree.h"
+#include "hash.h"
 #include "common/internal.h"
 #include "common/messages.h"
 #include "transaction.h"
@@ -836,6 +837,104 @@ int reset_imode(struct btrfs_trans_handle *trans, struct 
btrfs_root *root,
        return ret;
 }
 
+static int find_file_type(struct btrfs_root *root, u64 ino, u64 dirid,
+                         u64 index, const char *name, u32 name_len,
+                         u32 *imode_ret)
+{
+       struct btrfs_path path;
+       struct btrfs_key location;
+       struct btrfs_key key;
+       struct btrfs_dir_item *di;
+       char namebuf[BTRFS_NAME_LEN] = {0};
+       unsigned long cur;
+       unsigned long end;
+       bool found = false;
+       u8 filetype;
+       u32 len;
+       int ret;
+
+       btrfs_init_path(&path);
+
+       /* Search DIR_INDEX first */
+       key.objectid = dirid;
+       key.offset = index;
+       key.type = BTRFS_DIR_INDEX_KEY;
+
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+       if (ret > 0)
+               ret = -ENOENT;
+       if (ret < 0)
+               goto dir_item;
+       di = btrfs_item_ptr(path.nodes[0], path.slots[0],
+                              struct btrfs_dir_item);
+       btrfs_dir_item_key_to_cpu(path.nodes[0], di, &location);
+
+       /* Various basic check */
+       if (location.objectid != ino || location.type != BTRFS_INODE_ITEM_KEY ||
+           location.offset != 0)
+               goto dir_item;
+       filetype = btrfs_dir_type(path.nodes[0], di);
+       if (filetype >= BTRFS_FT_MAX || filetype == BTRFS_FT_UNKNOWN)
+               goto dir_item;
+       len = min_t(u32, btrfs_item_size_nr(path.nodes[0], path.slots[0]) -
+                        sizeof(*di), BTRFS_NAME_LEN);
+       len = min_t(u32, len, btrfs_dir_name_len(path.nodes[0], di));
+       read_extent_buffer(path.nodes[0], namebuf, (unsigned long)(di + 1), 
len);
+       if (name_len != len || memcmp(namebuf, name, len))
+               goto dir_item;
+
+       /* Got a correct filetype */
+       found = true;
+       *imode_ret = btrfs_type_to_imode(filetype);
+       ret = 0;
+       goto out;
+
+dir_item:
+       btrfs_release_path(&path);
+       key.objectid = dirid;
+       key.offset = btrfs_name_hash(name, name_len);
+
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+       if (ret > 0)
+               ret = -ENOENT;
+       if (ret < 0) {
+               btrfs_release_path(&path);
+               return ret;
+       }
+       cur = btrfs_item_ptr_offset(path.nodes[0], path.slots[0]);
+       end = cur + btrfs_item_size_nr(path.nodes[0], path.slots[0]);
+       while (cur < end) {
+               di = (struct btrfs_dir_item *)cur;
+               btrfs_dir_item_key_to_cpu(path.nodes[0], di, &location);
+               /* Various basic check */
+               if (location.objectid != ino ||
+                   location.type != BTRFS_INODE_ITEM_KEY ||
+                   location.offset != 0)
+                       goto next;
+               filetype = btrfs_dir_type(path.nodes[0], di);
+               if (filetype >= BTRFS_FT_MAX || filetype == BTRFS_FT_UNKNOWN)
+                       goto next;
+               len = min_t(u32, BTRFS_NAME_LEN,
+                           btrfs_item_size_nr(path.nodes[0], path.slots[0]) -
+                           sizeof(*di));
+               len = min_t(u32, len, btrfs_dir_name_len(path.nodes[0], di));
+               read_extent_buffer(path.nodes[0], namebuf,
+                                  (unsigned long)(di + 1), len);
+               if (name_len != len || memcmp(namebuf, name, len))
+                       goto next;
+               *imode_ret = btrfs_type_to_imode(filetype);
+               found = true;
+               goto out;
+next:
+               cur += btrfs_dir_name_len(path.nodes[0], di) + sizeof(*di);
+       }
+out:
+       btrfs_release_path(&path);
+       if (!found && !ret)
+               ret = -ENOENT;
+       return ret;
+}
+
 /*
  * Reset the inode mode of the inode specified by @path.
  *
-- 
2.23.0

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