On 2018年01月26日 17:31, Su Yue wrote:
>
>
> On 01/26/2018 05:14 PM, Qu Wenruo wrote:
>>
>>
>> On 2018年01月26日 16:35, Su Yue wrote:
>>> Introduce find_file_type_lowmem() and guess_file_type_lowmem().
>>>
>>> find_file_type_lowmem() gets filetypes from inode_item, dir_item and
>>> dir_index. If two of three's filetype are same and valid, it thinks
>>> the value is correct.
>>>
>>> guess_file_type_lowmem() searches file_extent and dir_item/index then
>>> returns with filetype.
>>>
>>> Signed-off-by: Su Yue <suy.fnst@xxxxxxxxxxxxxx>
>>> ---
>>> cmds-check.c | 193
>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 193 insertions(+)
>>>
>>> diff --git a/cmds-check.c b/cmds-check.c
>>> index e3505a7f9d6b..b200fdccf0e5 100644
>>> --- a/cmds-check.c
>>> +++ b/cmds-check.c
>>> @@ -3306,6 +3306,199 @@ static int find_file_type(struct inode_record
>>> *rec, u8 *type)
>>> return -ENOENT;
>>> }
>>> +/*
>>> + * Fetch filetype from exited completed dir_item, dir_index and
>>> inode_item.
>> ^^^^^^
>> existing?
>
> Oh.. a Typo.
>>> + * If two of tree items'filetype are same, we think the type is
>>> trusted.
>>> + *
>>> + * Return 0 if file type is found and BTRFS_FT_* is stored into type.
>>> + * Return <0 if file type is not found.
>>
>> This also includes extra error like -EIO from btrfs_search_slot().
>>
>>> + */
>>> +static int find_file_type_lowmem(struct btrfs_root *root, u64 ino,
>>> u8 *type)
>>> +{
>>> + struct btrfs_key key;
>>> + struct btrfs_path path;
>>> + struct btrfs_path path2;
>>> + struct btrfs_inode_ref *iref;
>>> + struct btrfs_dir_item *dir_item;
>>> + struct btrfs_dir_item *dir_index;
>>> + struct extent_buffer *eb;
>>> + u64 dir;
>>> + u64 index;
>>> + char namebuf[BTRFS_NAME_LEN] = {0};
>>> + u32 namelen;
>>> + u8 inode_filetype = BTRFS_FT_UNKNOWN;
>>> + u8 dir_item_filetype;
>>> + u8 dir_index_filetype;
>>> + u8 true_file_type;
>>> + int slot;
>>> + int ret;
>>> +
>>> + key.objectid = ino;
>>> + key.type = BTRFS_INODE_ITEM_KEY;
>>> + key.offset = 0;
>>> +
>>> + btrfs_init_path(&path);
>>> + ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
>>> + if (ret < 0)
>>> + goto out;
>>> + if (!ret) {
>>> + struct btrfs_inode_item *ii;
>>> +
>>> + ii = btrfs_item_ptr(path.nodes[0], path.slots[0],
>>> + struct btrfs_inode_item);
>>> + inode_filetype = imode_to_type(btrfs_inode_mode(path.nodes[0],
>>> + ii));
>>> + }
>>> +
>>> + key.objectid = ino;
>>> + key.type = BTRFS_INODE_REF_KEY;
>>> + key.offset = (u64)-1;
>>> +
>>> + btrfs_release_path(&path);
>>> + ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
>>> + if (ret < 0)
>>> + goto out;
>>> + if (!ret) {
>>> + ret = -EIO;
>>> + goto out;
>>> + }
>>> +
>>> + btrfs_init_path(&path2);
>>> +next:
>>> + btrfs_release_path(&path2)> + ret = btrfs_previous_item(root,
>>> &path, ino, BTRFS_INODE_REF_KEY);
>>> + if (ret) {
>>> + ret = -ENOENT;
>>
>> For ret < 0 case, return value is overwritten.
>>
> Will fix it.
>>
>>> + goto out;
>>> + }
>>> +
>>> + eb = path.nodes[0];
>>> + slot = path.slots[0];
>>> + btrfs_item_key_to_cpu(eb, &key, slot);
>>> + dir = key.offset;
>>> + iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
>>> + index = btrfs_inode_ref_index(eb, iref);
>>> + namelen = btrfs_inode_ref_name_len(eb, iref);
>>> + read_extent_buffer(eb, namebuf, (unsigned long)(iref + 1),
>>> namelen);
>>> +
>>> + dir_index = btrfs_lookup_dir_index(NULL, root, &path2, dir,
>>> namebuf,
>>> + namelen, index, 0);
>>> + if (!dir_index)
>>> + goto next;
>>> + dir_index_filetype = btrfs_dir_type(path2.nodes[0], dir_index);
>>> + btrfs_release_path(&path2);
>>> + if (dir_index_filetype == inode_filetype) {
>>> + true_file_type = inode_filetype;
>>> + goto found;
>>> + }
>>> +
>>> + dir_item = btrfs_lookup_dir_item(NULL, root, &path2, dir, namebuf,
>>> + namelen, 0);
>>> + if (!dir_item)
>>> + goto next;
>>> + dir_item_filetype = btrfs_dir_type(path2.nodes[0], dir_item);
>>> + btrfs_release_path(&path2);
>>> + if (dir_item_filetype == inode_filetype) {
>>> + true_file_type = inode_filetype;
>>> + goto found;
>>> + }
>>> +
>>> + if (dir_index_filetype == dir_item_filetype) {
>>> + true_file_type = dir_index_filetype;
>>> + goto found;
>>> + }
>>> + goto next;
>>> +found:
>>> + /* rare case, two of three items are both corrupted */
>>> + if (true_file_type == BTRFS_FT_UNKNOWN ||
>>> + true_file_type >= BTRFS_FT_MAX)
>>> + goto next;
>>> + *type = true_file_type;
>>> + ret = 0;
>>> +out:
>>> + btrfs_release_path(&path);
>>> + return ret;
>>> +}
>>> +
>>> +static int find_normal_file_extent(struct btrfs_root *root, u64 ino);
>>> +/*
>>> + * Try to determine inode type if type not found.
>>> + *
>>> + * For found regular file extent, it must be FILE.
>>> + * For found dir_item/index, it must be DIR.
>>> + *
>>> + * Return 0 if file type is confirmed and BTRFS_FT_* is stored into
>>> type.
>>> + * Return <0 if file type is unknown.
>>> + */
>>> +static int guess_file_type_lowmem(struct btrfs_root *root, u64 ino,
>>> u8 *type)
>>> +{
>>> + struct btrfs_key key;
>>> + struct btrfs_path *path = NULL;
>>> + bool is_dir = false;
>>> + bool is_file = false;
>>> + int ret;
>>> +
>>> + if (find_normal_file_extent(root, ino)) {
>>
>> Nice reusing the existing code.
>>
>>> + is_file = true;
>>> + goto out;
>>> + }
>>> +
>>> + key.objectid = ino;
>>> + key.type = BTRFS_DIR_ITEM_KEY;
>>
>> You could merge the code together, using just one loop instead of using
>> two search separately for DIR_ITEM and DIR_INDEX.
>>
>> Search for key (ino, DIR_INDEX, -1), as DIR_INDEX is larger than
>> DIR_ITEM.
>>
>> And search backward, not using btrfs_previous_item() but manually
>> checking the type (and do prev_leaf() manually).
>> It should save you several lines.
>>
> I have thought up this way. I prefer to call btrfs_previous_item()
> instead because it make code more readable and manually move path
> pointer is pretty tricky.
Double btrfs_previous_item() call would save you.
Although you need to pay extra attention after first
btrfs_previous_item() found no DIR_INDEX items.
In that case, you need to manually check the key type before call
btrfs_preivous_item() for DIR_ITEM.
Thanks,
Qu
>
> Since your suggestion is more efficient, I will do it in next version.
>
> Thanks,
> Su
>
>> Thanks,
>> Qu
>>
>>> + key.offset = (u64)-1;
>>> +
>>> + path = btrfs_alloc_path();
>>> + if (!path)
>>> + goto out;
>>> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
>>> + if (ret < 0)
>>> + goto out;
>>> + /*
>>> + * (u64)-1 may hit the hashed value in offset.
>>> + */
>>> + if (!ret) {
>>> + is_dir = true;
>>> + goto out;
>>> + }
>>> +
>>> + ret = btrfs_previous_item(root, path, ino, BTRFS_DIR_ITEM_KEY);>
>>> + if (!ret) {
>>> + is_dir = true;
>>> + goto out;
>>> + }
>>> +
>>> + key.type = BTRFS_DIR_INDEX_KEY;
>>> + key.offset = (u64)-1;
>>> +
>>> + btrfs_release_path(path);
>>> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
>>> + if (ret < 0)
>>> + goto out;
>>> + if (!ret) {
>>> + is_dir = true;
>>> + goto out;
>>> + }
>>> + ret = btrfs_previous_item(root, path, ino, BTRFS_DIR_INDEX_KEY);
>>> + if (!ret) {
>>> + is_dir = true;
>>> + goto out;
>>> + }
>>> +out:
>>> + if (path)
>>> + btrfs_release_path(path);
>>> +
>>> + if (is_dir) {
>>> + *type = BTRFS_FT_DIR;
>>> + ret = 0;
>>> + } else if (is_file) {
>>> + *type = BTRFS_FT_REG_FILE;
>>> + ret = 0;
>>> + } else {
>>> + ret = -ENOENT;
>>> + }
>>> + return ret;
>>> +}
>>> +
>>> /*
>>> * To determine the file name for nlink repair
>>> *
>>>
>>
>
>
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