filesystems/bcachefs/casefolding.rst

1 .. SPDX-License-Identifier: GPL-2.0
6 bcachefs has support for case-insensitive file and directory
13 Taking advantage of file-system level casefolding can lead to great
16 Casefolding support requires a kernel with the `CONFIG_UNICODE` enabled.
24 string of `BCH_NAME_MAX` length using the `utf8_casefold` function to
25 casefold the query string.
28 hash is made from the casefolded string and storing the cached casefolded
37 vary per-key, and they may not even be present if the key is aligned to
45 ---------
49 the hash system only has support for a single key type. This would also need
55 not be true, if the uppercase unicode glyph had a different UTF-8 encoding than
58 decided to simply encode the two string lengths in the key to avoid random
61 The option settled on was to use a free-bit in d_type to mark a dirent as having
65 The feature bit was used to allow casefolding support to be enabled for the majority
70 Other filesystems like ext4 and f2fs have a super-block level option for casefolding
72 any encodings than a single UTF-8 version. When future encodings are desirable,
76 ----------------------------
83  - Lookup file "blAH" in a casefolded directory
84  - Creation of file "BLAH" in a casefolded directory
85  - Lookup file "blAH" in a casefolded directory