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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:12 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:12 +0000 |
commit | 8665bd53f2f2e27e5511d90428cb3f60e6d0ce15 (patch) | |
tree | 8d58900dc0ebd4a3011f92c128d2fe45bc7c4bf2 /fs/bcachefs/dirent_format.h | |
parent | Adding debian version 6.7.12-1. (diff) | |
download | linux-8665bd53f2f2e27e5511d90428cb3f60e6d0ce15.tar.xz linux-8665bd53f2f2e27e5511d90428cb3f60e6d0ce15.zip |
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/bcachefs/dirent_format.h')
-rw-r--r-- | fs/bcachefs/dirent_format.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/fs/bcachefs/dirent_format.h b/fs/bcachefs/dirent_format.h new file mode 100644 index 0000000000..5e116b88e8 --- /dev/null +++ b/fs/bcachefs/dirent_format.h @@ -0,0 +1,42 @@ +/* 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 */ |