mirror of
https://github.com/torvalds/linux.git
synced 2024-12-11 21:52:04 +00:00
43 lines
1.0 KiB
C
43 lines
1.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _BCACHEFS_DIRENT_FORMAT_H
|
|
#define _BCACHEFS_DIRENT_FORMAT_H
|
|
|
|
/*
|
|
* Dirents (and xattrs) have to implement string lookups; since our b-tree
|
|
* doesn't support arbitrary length strings for the key, we instead index by a
|
|
* 64 bit hash (currently truncated sha1) of the string, stored in the offset
|
|
* field of the key - using linear probing to resolve hash collisions. This also
|
|
* provides us with the readdir cookie posix requires.
|
|
*
|
|
* Linear probing requires us to use whiteouts for deletions, in the event of a
|
|
* collision:
|
|
*/
|
|
|
|
struct bch_dirent {
|
|
struct bch_val v;
|
|
|
|
/* Target inode number: */
|
|
union {
|
|
__le64 d_inum;
|
|
struct { /* DT_SUBVOL */
|
|
__le32 d_child_subvol;
|
|
__le32 d_parent_subvol;
|
|
};
|
|
};
|
|
|
|
/*
|
|
* Copy of mode bits 12-15 from the target inode - so userspace can get
|
|
* the filetype without having to do a stat()
|
|
*/
|
|
__u8 d_type;
|
|
|
|
__u8 d_name[];
|
|
} __packed __aligned(8);
|
|
|
|
#define DT_SUBVOL 16
|
|
#define BCH_DT_MAX 17
|
|
|
|
#define BCH_NAME_MAX 512
|
|
|
|
#endif /* _BCACHEFS_DIRENT_FORMAT_H */
|