[PATCH v2 2/6] btrfs-progs: check/common: Introduce a function to find imode using INODE_REF

Qu Wenruo
2019-09-05T07:58:16Z

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 <wqu@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