On 2018年01月26日 17:14, 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?
>> + * 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.
>
>
>> + 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.
In fact you could use btrfs_previous_item() twice, to locate any
DIR_INDEX/DIR_ITEM.
btrfs_previous_item(DIR_INDEX) to locate any DIR_INDEX, and then
btrfs_previous_item(DIR_ITEM) again if DIR_INDEX not found.
Thanks,
Qu
>
> 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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