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d37c14ac6f
This patch implements support for case-insensitive file name lookups in bcachefs. The implementation uses the same UTF-8 lowering and normalization that ext4 and f2fs is using. More information is provided in Documentation/bcachefs/casefolding.rst Compatibility notes: This uses the new versioning scheme for incompatible features where an incompatible feature is tied to a version number: the superblock says "we may use incompat features up to x" and "incompat features up to x are in use", disallowing mounting by previous versions. Additionally, and old style incompat feature bit is used, so that kernels without utf8 casefolding support know if casefolding specifically is in use and they're allowed to mount. Signed-off-by: Joshua Ashton <joshua@froggi.es> Cc: André Almeida <andrealmeid@igalia.com> Cc: Gabriel Krisman Bertazi <krisman@suse.de> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
59 lines
1.4 KiB
C
59 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_DIRENT_FORMAT_H
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#define _BCACHEFS_DIRENT_FORMAT_H
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/*
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* Dirents (and xattrs) have to implement string lookups; since our b-tree
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* doesn't support arbitrary length strings for the key, we instead index by a
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* 64 bit hash (currently truncated sha1) of the string, stored in the offset
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* field of the key - using linear probing to resolve hash collisions. This also
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* provides us with the readdir cookie posix requires.
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*
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* Linear probing requires us to use whiteouts for deletions, in the event of a
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* collision:
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*/
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struct bch_dirent {
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struct bch_val v;
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/* Target inode number: */
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union {
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__le64 d_inum;
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struct { /* DT_SUBVOL */
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__le32 d_child_subvol;
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__le32 d_parent_subvol;
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};
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};
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/*
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* Copy of mode bits 12-15 from the target inode - so userspace can get
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* the filetype without having to do a stat()
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*/
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#if defined(__LITTLE_ENDIAN_BITFIELD)
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__u8 d_type:5,
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d_unused:2,
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d_casefold:1;
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#elif defined(__BIG_ENDIAN_BITFIELD)
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__u8 d_casefold:1,
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d_unused:2,
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d_type:5;
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#endif
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union {
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struct {
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__u8 d_pad;
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__le16 d_name_len;
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__le16 d_cf_name_len;
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__u8 d_names[];
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} d_cf_name_block __packed;
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__DECLARE_FLEX_ARRAY(__u8, d_name);
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} __packed;
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} __packed __aligned(8);
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#define DT_SUBVOL 16
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#define BCH_DT_MAX 17
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#define BCH_NAME_MAX 512
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#endif /* _BCACHEFS_DIRENT_FORMAT_H */
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