Since the default ext4 group desc size is 64 now (assuming that the
64-bit feature is enbled). And the size mentioned in this doc is 64 too.
Change it to 64.
Signed-off-by: Wu Bo <bo.wu@vivo.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20230222013525.14748-1-bo.wu@vivo.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The description of s_lastcheck_hi, s_first_error_time_hi, and
s_last_error_time_hi fields refer to themselves, while these means
referring to upper 8 bits (byte) of corresponding fields (s_lastcheck,
s_first_error_time, and s_last_error_time). Correct the mistake.
Signed-off-by: JunChao Sun <sunjunchao2870@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220815125233.2040-1-sunjunchao2870@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Commit 3103084afc ("ext4, doc: remove unnecessary escaping") removes
redundant underscore escaping, however the cell spacing in heading row of
blockmap table became not aligned anymore, hence triggers malformed table
warning:
Documentation/filesystems/ext4/blockmap.rst:3: WARNING: Malformed table.
+---------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| i.i_block Offset | Where It Points |
<snipped>...
The warning caused the table not being loaded.
Realign the heading row cell by adding missing space at the first cell
to fix the warning.
Fixes: 3103084afc ("ext4, doc: remove unnecessary escaping")
Cc: stable@kernel.org
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Wang Jianjian <wangjianjian3@huawei.com>
Cc: linux-ext4@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20220619072938.7334-1-bagasdotme@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The new file Documentation/orphan/ext4.rst escapes underscores ("\_")
throughout. However, RST doesn't actually require that, so the escaping
only succeeds in making the document less readable. Remove the unneeded
escapes.
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210902220854.198850-3-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Commit 3a6541e97c (Add documentation about the orphan file feature) added
a new document on orphan files, which is great. But the use of
"list-table" results in documents that are absolutely unreadable in their
plain-text form. Switch this file to the regular RST table format instead;
the rendered (HTML) output is identical.
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210902220854.198850-2-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
ext4 in 5.14:
- Allow applications to poll on changes to /sys/fs/ext4/*/errors_count
- Add the ioctl EXT4_IOC_CHECKPOINT which allows the journal to be
checkpointed, truncated and discarded or zero'ed.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"In addition to bug fixes and cleanups, there are two new features for
ext4 in 5.14:
- Allow applications to poll on changes to
/sys/fs/ext4/*/errors_count
- Add the ioctl EXT4_IOC_CHECKPOINT which allows the journal to be
checkpointed, truncated and discarded or zero'ed"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits)
jbd2: export jbd2_journal_[un]register_shrinker()
ext4: notify sysfs on errors_count value change
fs: remove bdev_try_to_free_page callback
ext4: remove bdev_try_to_free_page() callback
jbd2: simplify journal_clean_one_cp_list()
jbd2,ext4: add a shrinker to release checkpointed buffers
jbd2: remove redundant buffer io error checks
jbd2: don't abort the journal when freeing buffers
jbd2: ensure abort the journal if detect IO error when writing original buffer back
jbd2: remove the out label in __jbd2_journal_remove_checkpoint()
ext4: no need to verify new add extent block
jbd2: clean up misleading comments for jbd2_fc_release_bufs
ext4: add check to prevent attempting to resize an fs with sparse_super2
ext4: consolidate checks for resize of bigalloc into ext4_resize_begin
ext4: remove duplicate definition of ext4_xattr_ibody_inline_set()
ext4: fsmap: fix the block/inode bitmap comment
ext4: fix comment for s_hash_unsigned
ext4: use local variable ei instead of EXT4_I() macro
ext4: fix avefreec in find_group_orlov
ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit
...
Add a section about journal checkpointing, including information about
the ioctl EXT4_IOC_CHECKPOINT which can be used to trigger a journal
checkpoint from userspace.
Also, update the journal allocation information to reflect that up to
10240000 blocks are used for the journal and that the journal is not
necessarily contiguous.
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Changes in v5:
- clarify behavior of DRY_RUN flag
Link: https://lore.kernel.org/r/20210518151327.130198-3-leah.rumancik@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The conversion tools used during DocBook/LaTeX/html/Markdown->ReST
conversion and some cut-and-pasted text contain some characters that
aren't easily reachable on standard keyboards and/or could cause
troubles when parsed by the documentation build system.
Replace the occurences of the following characters:
- U+2217 ('∗'): ASTERISK OPERATOR
use ASCII asterisk instead of the ASTERISK OPERATOR
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/c5c3c384c48779ca7c9dcd90183cefe20ac82928.1623826294.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This adds support for encryption with casefolding.
Since the name on disk is case preserving, and also encrypted, we can no
longer just recompute the hash on the fly. Additionally, to avoid
leaking extra information from the hash of the unencrypted name, we use
siphash via an fscrypt v2 policy.
The hash is stored at the end of the directory entry for all entries
inside of an encrypted and casefolded directory apart from those that
deal with '.' and '..'. This way, the change is backwards compatible
with existing ext4 filesystems.
[ Changed to advertise this feature via the file:
/sys/fs/ext4/features/encrypted_casefold -- TYT ]
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20210319073414.1381041-2-drosen@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fast commit on-disk format is designed such that the replay of these
tags can be idempotent. This patch adds documentation in the code in
form of comments and in form kernel docs that describes these
characteristics. This patch also adds a TODO item needed to ensure
kernel fast commit replay idempotence.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201119232822.1860882-1-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fast commit feature has flags in the file system as well in JBD2. The
meaning of fast commit feature flags can get confusing. Update docs
and code to add more documentation about it.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201106035911.1942128-2-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200706190339.20709-1-grandmaster@al2klimov.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Verity and DAX are incompatible. Changing the DAX mode due to a verity
flag change is wrong without a corresponding address_space_operations
update.
Make the 2 options mutually exclusive by returning an error if DAX was
set first.
(Setting DAX is already disabled if Verity is set first.)
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200528150003.828793-3-ira.weiny@intel.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
about the state of the extent status cache.
Dropped workaround for pre-1970 dates which were encoded incorrectly
in pre-4.4 kernels. Since both the kernel correctly generates, and
e2fsck detects and fixes this issue for the past four years, it'e time
to drop the workaround. (Also, it's not like files with dates in the
distant past were all that common in the first place.)
A lot of miscellaneous bug fixes and cleanups, including some ext4
Documentation fixes. Also included are two minor bug fixes in
fs/unicode.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Added new ext4 debugging ioctls to allow userspace to get information
about the state of the extent status cache.
Dropped workaround for pre-1970 dates which were encoded incorrectly
in pre-4.4 kernels. Since both the kernel correctly generates, and
e2fsck detects and fixes this issue for the past four years, it'e time
to drop the workaround. (Also, it's not like files with dates in the
distant past were all that common in the first place.)
A lot of miscellaneous bug fixes and cleanups, including some ext4
Documentation fixes. Also included are two minor bug fixes in
fs/unicode"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
unicode: make array 'token' static const, makes object smaller
unicode: Move static keyword to the front of declarations
ext4: add missing bigalloc documentation.
ext4: fix kernel oops caused by spurious casefold flag
ext4: fix integer overflow when calculating commit interval
ext4: use percpu_counters for extent_status cache hits/misses
ext4: fix potential use after free after remounting with noblock_validity
jbd2: add missing tracepoint for reserved handle
ext4: fix punch hole for inline_data file systems
ext4: rework reserved cluster accounting when invalidating pages
ext4: documentation fixes
ext4: treat buffers with write errors as containing valid data
ext4: fix warning inside ext4_convert_unwritten_extents_endio
ext4: set error return correctly when ext4_htree_store_dirent fails
ext4: drop legacy pre-1970 encoding workaround
ext4: add new ioctl EXT4_IOC_GET_ES_CACHE
ext4: add a new ioctl EXT4_IOC_GETSTATE
ext4: add a new ioctl EXT4_IOC_CLEAR_ES_CACHE
jbd2: flush_descriptor(): Do not decrease buffer head's ref count
ext4: remove unnecessary error check
...
This commit aims to fix the following issues in ext4 documentation:
- Flexible block group docs said that the aim was to group block
metadata together instead of block group metadata.
- The documentation consistly uses "location" instead of "block number".
It is easy to confuse location to be an absolute offset on disk. Added
a line to clarify all location values are in terms of block numbers.
- Dirent2 docs said that the rec_len field is shortened instead of the
name_len field.
- Typo in bg_checksum description.
- Inode size is 160 bytes now, and hence i_extra_isize is now 32.
- Cluster size formula was incorrect, it did not include the +10 to
s_log_cluster_size value.
- Typo: there were two s_wtime_hi in the superblock struct.
- Superblock struct was outdated, added the new fields which were part
of s_reserved earlier.
- Multiple mount protection seems to be implemented in fs/ext4/mmp.c.
Signed-off-by: Ayush Ranjan <ayushr2@illinois.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Document the format of verity files on ext4, and the corresponding inode
and superblock flags.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
There's no need to use a .rst on Sphinx toc tables. As most of
the Documentation don't use, remove the remaing occurrences.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Move the ext4 data structures book to Documentation/filesystems/ext4/
since the administrative information moved elsewhere.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Move the ext4 mount option and other administrative stuff to the Linux
administrator's guide.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The tables in the ext4 readme are not particularly space efficient in
the text or html outputs, and they're totally broken in the pdf output.
Convert them into titled paragraphs so that they render more nicely.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
It turns out that the latex table formatters lay out table columns with
the exact proportional widths given in the table metadata, even if text
overflows outside the box. This was not caught during the initial
import because the HTML renderers are smart enough to fudge the table.
Fix the table column width formatting problems in the data structures
and algorithms documentation so that we don't have squashed columns.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The superblock timestamp fields were enlarged by u8 to be 40 bits wide.
Update the documentation to reflect this.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Create a new top-level section for documentation of filesystem usage,
on-disk format information, and anything else.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about extended attributes from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about directory layout from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about inode data fork from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about inodes from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about the journal from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about multi-mount protection from the on-disk format
wiki page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about bitmaps from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about group descriptors from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about superblocks from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Import the chapter about high level design from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Create the basic structure of the "new" data structures & algorithms
book to be ported over from the on-disk format wiki, and then start by
pulling in the introductory information.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Convert the existing ext4 documentation into rst format and link it in
with the rest of the kernel documentation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Move Documentation/filesystems/ext4.txt into
Documentation/filesystems/ext4/ext4.rst in preparation for adding more
ext4 documentation.
Note that the documentation isn't in rst format yet, but as it's not
linked from anywhere it won't cause build errors.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
