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authorLinus Torvalds <torvalds@linux-foundation.org>2021-05-01 01:35:30 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-01 01:35:30 +0300
commit9f67672a817ec046f7554a885f0fe0d60e1bf99f (patch)
tree9d238a2cbfabc479bdb31c5879b8f24415dc3aa2 /Documentation/filesystems
parent6bab076a3d2ff4298483c1a3b77162811b451863 (diff)
parent6c0912739699d8e4b6a87086401bf3ad3c59502d (diff)
downloadlinux-9f67672a817ec046f7554a885f0fe0d60e1bf99f.tar.xz
Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o: "New features for ext4 this cycle include support for encrypted casefold, ensure that deleted file names are cleared in directory blocks by zeroing directory entries when they are unlinked or moved as part of a hash tree node split. We also improve the block allocator's performance on a freshly mounted file system by prefetching block bitmaps. There are also the usual cleanups and bug fixes, including fixing a page cache invalidation race when there is mixed buffered and direct I/O and the block size is less than page size, and allow the dax flag to be set and cleared on inline directories" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits) ext4: wipe ext4_dir_entry2 upon file deletion ext4: Fix occasional generic/418 failure fs: fix reporting supported extra file attributes for statx() ext4: allow the dax flag to be set and cleared on inline directories ext4: fix debug format string warning ext4: fix trailing whitespace ext4: fix various seppling typos ext4: fix error return code in ext4_fc_perform_commit() ext4: annotate data race in jbd2_journal_dirty_metadata() ext4: annotate data race in start_this_handle() ext4: fix ext4_error_err save negative errno into superblock ext4: fix error code in ext4_commit_super ext4: always panic when errors=panic is specified ext4: delete redundant uptodate check for buffer ext4: do not set SB_ACTIVE in ext4_orphan_cleanup() ext4: make prefetch_block_bitmaps default ext4: add proc files to monitor new structures ext4: improve cr 0 / cr 1 group scanning ext4: add MB_NUM_ORDERS macro ext4: add mballoc stats proc file ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/ext4/directory.rst27
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/filesystems/ext4/directory.rst b/Documentation/filesystems/ext4/directory.rst
index 073940cc64ed..55f618b37144 100644
--- a/Documentation/filesystems/ext4/directory.rst
+++ b/Documentation/filesystems/ext4/directory.rst
@@ -121,6 +121,31 @@ The directory file type is one of the following values:
* - 0x7
- Symbolic link.
+To support directories that are both encrypted and casefolded directories, we
+must also include hash information in the directory entry. We append
+``ext4_extended_dir_entry_2`` to ``ext4_dir_entry_2`` except for the entries
+for dot and dotdot, which are kept the same. The structure follows immediately
+after ``name`` and is included in the size listed by ``rec_len`` If a directory
+entry uses this extension, it may be up to 271 bytes.
+
+.. list-table::
+ :widths: 8 8 24 40
+ :header-rows: 1
+
+ * - Offset
+ - Size
+ - Name
+ - Description
+ * - 0x0
+ - \_\_le32
+ - hash
+ - The hash of the directory name
+ * - 0x4
+ - \_\_le32
+ - minor\_hash
+ - The minor hash of the directory name
+
+
In order to add checksums to these classic directory blocks, a phony
``struct ext4_dir_entry`` is placed at the end of each leaf block to
hold the checksum. The directory entry is 12 bytes long. The inode
@@ -322,6 +347,8 @@ The directory hash is one of the following values:
- Half MD4, unsigned.
* - 0x5
- Tea, unsigned.
+ * - 0x6
+ - Siphash.
Interior nodes of an htree are recorded as ``struct dx_node``, which is
also the full length of a data block: