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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"This merge window saw the the following new featuers added to ext4:
- Direct I/O via iomap (required the iomap-for-next branch from
Darrick as a prereq).
- Support for using dioread-nolock where the block size < page size.
- Support for encryption for file systems where the block size < page
size.
- Rework of journal credits handling so a revoke-heavy workload will
not cause the journal to run out of space.
- Replace bit-spinlocks with spinlocks in jbd2
Also included were some bug fixes and cleanups, mostly to clean up
corner cases from fuzzed file systems and error path handling"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (59 commits)
ext4: work around deleting a file with i_nlink == 0 safely
ext4: add more paranoia checking in ext4_expand_extra_isize handling
jbd2: make jbd2_handle_buffer_credits() handle reserved handles
ext4: fix a bug in ext4_wait_for_tail_page_commit
ext4: bio_alloc with __GFP_DIRECT_RECLAIM never fails
ext4: code cleanup for get_next_id
ext4: fix leak of quota reservations
ext4: remove unused variable warning in parse_options()
ext4: Enable encryption for subpage-sized blocks
fs/buffer.c: support fscrypt in block_read_full_page()
ext4: Add error handling for io_end_vec struct allocation
jbd2: Fine tune estimate of necessary descriptor blocks
jbd2: Provide trace event for handle restarts
ext4: Reserve revoke credits for freed blocks
jbd2: Make credit checking more strict
jbd2: Rename h_buffer_credits to h_total_credits
jbd2: Reserve space for revoke descriptor blocks
jbd2: Drop jbd2_space_needed()
jbd2: Account descriptor blocks into t_outstanding_credits
jbd2: Factor out common parts of stopping and restarting a handle
...
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IV_INO_LBLK_64 encryption policies have special requirements from the
filesystem beyond those of the existing encryption policies:
- Inode numbers must never change, even if the filesystem is resized.
- Inode numbers must be <= 32 bits.
- File logical block numbers must be <= 32 bits.
ext4 has 32-bit inode and file logical block numbers. However,
resize2fs can re-number inodes when shrinking an ext4 filesystem.
However, typically the people who would want to use this format don't
care about filesystem shrinking. They'd be fine with a solution that
just prevents the filesystem from being shrunk.
Therefore, add a new feature flag EXT4_FEATURE_COMPAT_STABLE_INODES that
will do exactly that. Then wire up the fscrypt_operations to expose
this flag to fs/crypto/, so that it allows IV_INO_LBLK_64 policies when
this flag is set.
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
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So far we have reserved only relatively high fixed amount of revoke
credits for each transaction. We over-reserved by large amount for most
cases but when freeing large directories or files with data journalling,
the fixed amount is not enough. In fact the worst case estimate is
inconveniently large (maximum extent size) for freeing of one extent.
We fix this by doing proper estimate of the amount of blocks that need
to be revoked when removing blocks from the inode due to truncate or
hole punching and otherwise reserve just a small amount of revoke
credits for each transaction to accommodate freeing of xattrs block or
so.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-23-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Provide ext4_journal_ensure_credits_fn() function to ensure transaction
has given amount of credits and call helper function to prepare for
restarting a transaction. This allows to remove some boilerplate code
from various places, add proper error handling for the case where
transaction extension or restart fails, and reduces following changes
needed for proper revoke record reservation tracking.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-10-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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This patch introduces a new direct I/O write path which makes use of
the iomap infrastructure.
All direct I/O writes are now passed from the ->write_iter() callback
through to the new direct I/O handler ext4_dio_write_iter(). This
function is responsible for calling into the iomap infrastructure via
iomap_dio_rw().
Code snippets from the existing direct I/O write code within
ext4_file_write_iter() such as, checking whether the I/O request is
unaligned asynchronous I/O, or whether the write will result in an
overwrite have effectively been moved out and into the new direct I/O
->write_iter() handler.
The block mapping flags that are eventually passed down to
ext4_map_blocks() from the *_get_block_*() suite of routines have been
taken out and introduced within ext4_iomap_alloc().
For inode extension cases, ext4_handle_inode_extension() is
effectively the function responsible for performing such metadata
updates. This is called after iomap_dio_rw() has returned so that we
can safely determine whether we need to potentially truncate any
allocated blocks that may have been prepared for this direct I/O
write. We don't perform the inode extension, or truncate operations
from the ->end_io() handler as we don't have the original I/O 'length'
available there. The ->end_io() however is responsible fo converting
allocated unwritten extents to written extents.
In the instance of a short write, we fallback and complete the
remainder of the I/O using buffered I/O via
ext4_buffered_write_iter().
The existing buffer_head direct I/O implementation has been removed as
it's now redundant.
[ Fix up ext4_dio_write_iter() per Jan's comments at
https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ]
Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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As part of the ext4_iomap_begin() cleanups that precede this patch, we
also split up the IOMAP_REPORT branch into a completely separate
->iomap_begin() callback named ext4_iomap_begin_report(). Again, the
raionale for this change is to reduce the overall clutter within
ext4_iomap_begin().
Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/5c97a569e26ddb6696e3d3ac9fbde41317e029a0.1572949325.git.mbobrowski@mbobrowski.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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This patch adds the support for blocksize < pagesize for
dioread_nolock feature.
Since in case of blocksize < pagesize, we can have multiple
small buffers of page as unwritten extents, we need to
maintain a vector of these unwritten extents which needs
the conversion after the IO is complete. Thus, we maintain
a list of tuple <offset, size> pair (io_end_vec) for this &
traverse this list to do the unwritten to written conversion.
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20191016073711.4141-5-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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This patch just brings in the API for conversion of unwritten io_end_vec
extents which will be required for blocksize < pagesize support
for dioread_nolock feature.
No functional changes in this patch.
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20191016073711.4141-3-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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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
...
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git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground
Pull y2038 vfs updates from Arnd Bergmann:
"Add inode timestamp clamping.
This series from Deepa Dinamani adds a per-superblock minimum/maximum
timestamp limit for a file system, and clamps timestamps as they are
written, to avoid random behavior from integer overflow as well as
having different time stamps on disk vs in memory.
At mount time, a warning is now printed for any file system that can
represent current timestamps but not future timestamps more than 30
years into the future, similar to the arbitrary 30 year limit that was
added to settimeofday().
This was picked as a compromise to warn users to migrate to other file
systems (e.g. ext4 instead of ext3) when they need the file system to
survive beyond 2038 (or similar limits in other file systems), but not
get in the way of normal usage"
* tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground:
ext4: Reduce ext4 timestamp warnings
isofs: Initialize filesystem timestamp ranges
pstore: fs superblock limits
fs: omfs: Initialize filesystem timestamp ranges
fs: hpfs: Initialize filesystem timestamp ranges
fs: ceph: Initialize filesystem timestamp ranges
fs: sysv: Initialize filesystem timestamp ranges
fs: affs: Initialize filesystem timestamp ranges
fs: fat: Initialize filesystem timestamp ranges
fs: cifs: Initialize filesystem timestamp ranges
fs: nfs: Initialize filesystem timestamp ranges
ext4: Initialize timestamps limits
9p: Fill min and max timestamps in sb
fs: Fill in max and min timestamps in superblock
utimes: Clamp the timestamps before update
mount: Add mount warning for impending timestamp expiry
timestamp_truncate: Replace users of timespec64_trunc
vfs: Add timestamp_truncate() api
vfs: Add file timestamp range support
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When ext4 file systems were created intentionally with 128 byte inodes,
the rate-limited warning of eventual possible timestamp overflow are
still emitted rather frequently. Remove the warning for now.
Discussion for whether any warning is needed,
and where it should be emitted, can be found at
https://lore.kernel.org/lkml/1567523922.5576.57.camel@lca.pw/.
I can post a separate follow-up patch after the conclusion.
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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ext4 has different overflow limits for max filesystem
timestamps based on the extra bytes available.
The timestamp limits are calculated according to the
encoding table in
a4dad1ae24f85i(ext4: Fix handling of extended tv_sec):
* extra msb of adjust for signed
* epoch 32-bit 32-bit tv_sec to
* bits time decoded 64-bit tv_sec 64-bit tv_sec valid time range
* 0 0 1 -0x80000000..-0x00000001 0x000000000 1901-12-13..1969-12-31
* 0 0 0 0x000000000..0x07fffffff 0x000000000 1970-01-01..2038-01-19
* 0 1 1 0x080000000..0x0ffffffff 0x100000000 2038-01-19..2106-02-07
* 0 1 0 0x100000000..0x17fffffff 0x100000000 2106-02-07..2174-02-25
* 1 0 1 0x180000000..0x1ffffffff 0x200000000 2174-02-25..2242-03-16
* 1 0 0 0x200000000..0x27fffffff 0x200000000 2242-03-16..2310-04-04
* 1 1 1 0x280000000..0x2ffffffff 0x300000000 2310-04-04..2378-04-22
* 1 1 0 0x300000000..0x37fffffff 0x300000000 2378-04-22..2446-05-10
Note that the time limits are not correct for deletion times.
Added a warn when an inode cannot be extended to incorporate an
extended timestamp.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: tytso@mit.edu
Cc: adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org
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Remount process will release system zone which was allocated before if
"noblock_validity" is specified. If we mount an ext4 file system to two
mountpoints with default mount options, and then remount one of them
with "noblock_validity", it may trigger a use after free problem when
someone accessing the other one.
# mount /dev/sda foo
# mount /dev/sda bar
User access mountpoint "foo" | Remount mountpoint "bar"
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ext4_map_blocks() | ext4_remount()
check_block_validity() | ext4_setup_system_zone()
ext4_data_block_valid() | ext4_release_system_zone()
| free system_blks rb nodes
access system_blks rb nodes |
trigger use after free |
This problem can also be reproduced by one mountpint, At the same time,
add_system_zone() can get called during remount as well so there can be
racing ext4_data_block_valid() reading the rbtree at the same time.
This patch add RCU to protect system zone from releasing or building
when doing a remount which inverse current "noblock_validity" mount
option. It assign the rbtree after the whole tree was complete and
do actual freeing after rcu grace period, avoid any intermediate state.
Reported-by: syzbot+1e470567330b7ad711d5@syzkaller.appspotmail.com
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
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The goal of this patch is to remove two references to the buffer delay
bit in ext4_da_page_release_reservation() as part of a larger effort
to remove all such references from ext4. These two references are
principally used to reduce the reserved block/cluster count when pages
are invalidated as a result of truncating, punching holes, or
collapsing a block range in a file. The entire function is removed
and replaced with code in ext4_es_remove_extent() that reduces the
reserved count as a side effect of removing a block range from delayed
and not unwritten extents in the extent status tree as is done when
truncating, punching holes, or collapsing ranges.
The code is written to minimize the number of searches descending from
rb tree roots for scalability.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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I got some errors when I repair an ext4 volume which stacked by an
iscsi target:
Entry 'test60' in / (2) has deleted/unused inode 73750. Clear?
It can be reproduced when the network not good enough.
When I debug this I found ext4 will read entry buffer from disk and
the buffer is marked with write_io_error.
If the buffer is marked with write_io_error, it means it already
wroten to journal, and not checked out to disk. IOW, the journal
is newer than the data in disk.
If this journal record 'delete test60', it means the 'test60' still
on the disk metadata.
In this case, if we read the buffer from disk successfully and create
file continue, the new journal record will overwrite the journal
which record 'delete test60', then the entry corruptioned.
So, use the buffer rather than read from disk if the buffer is marked
with write_io_error.
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Make ext4_mpage_readpages() verify data as it is read from fs-verity
files, using the helper functions from fs/verity/.
To support both encryption and verity simultaneously, this required
refactoring the decryption workflow into a generic "post-read
processing" workflow which can do decryption, verification, or both.
The case where the ext4 block size is not equal to the PAGE_SIZE is not
supported yet, since in that case ext4_mpage_readpages() sometimes falls
back to block_read_full_page(), which does not support fs-verity yet.
Co-developed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Add most of fs-verity support to ext4. fs-verity is a filesystem
feature that enables transparent integrity protection and authentication
of read-only files. It uses a dm-verity like mechanism at the file
level: a Merkle tree is used to verify any block in the file in
log(filesize) time. It is implemented mainly by helper functions in
fs/verity/. See Documentation/filesystems/fsverity.rst for the full
documentation.
This commit adds all of ext4 fs-verity support except for the actual
data verification, including:
- Adding a filesystem feature flag and an inode flag for fs-verity.
- Implementing the fsverity_operations to support enabling verity on an
inode and reading/writing the verity metadata.
- Updating ->write_begin(), ->write_end(), and ->writepages() to support
writing verity metadata pages.
- Calling the fs-verity hooks for ->open(), ->setattr(), and ->ioctl().
ext4 stores the verity metadata (Merkle tree and fsverity_descriptor)
past the end of the file, starting at the first 64K boundary beyond
i_size. This approach works because (a) verity files are readonly, and
(b) pages fully beyond i_size aren't visible to userspace but can be
read/written internally by ext4 with only some relatively small changes
to ext4. This approach avoids having to depend on the EA_INODE feature
and on rearchitecturing ext4's xattr support to support paging
multi-gigabyte xattrs into memory, and to support encrypting xattrs.
Note that the verity metadata *must* be encrypted when the file is,
since it contains hashes of the plaintext data.
This patch incorporates work by Theodore Ts'o and Chandan Rajendra.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Originally, support for expanded timestamps had a bug in that pre-1970
times were erroneously encoded as being in the the 24th century. This
was fixed in commit a4dad1ae24f8 ("ext4: Fix handling of extended
tv_sec") which landed in 4.4. Starting with 4.4, pre-1970 timestamps
were correctly encoded, but for backwards compatibility those
incorrectly encoded timestamps were mapped back to the pre-1970 dates.
Given that backwards compatibility workaround has been around for 4
years, and given that running e2fsck from e2fsprogs 1.43.2 and later
will offer to fix these timestamps (which has been released for 3
years), it's past time to drop the legacy workaround from the kernel.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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For debugging reasons, it's useful to know the contents of the extent
cache. Since the extent cache contains much of what is in the fiemap
ioctl, use an fiemap-style interface to return this information.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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The new ioctl EXT4_IOC_GETSTATE returns some of the dynamic state of
an ext4 inode for debugging purposes.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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The new ioctl EXT4_IOC_CLEAR_ES_CACHE will force an inode's extent
status cache to be cleared out. This is intended for use for
debugging.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Clean up namespace pollution by the inline_data code.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Move the calculation of the location of the dirent tail into
initialize_dirent_tail(). Also prefix the function with ext4_ to fix
kernel namepsace polution.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Functions such as ext4_dirent_csum_verify() and ext4_dirent_csum_set()
don't actually operate on a directory entry, but a directory block.
And while they take a struct ext4_dir_entry *dirent as an argument, it
had better be the first directory at the beginning of the direct
block, or things will go very wrong.
Rename the following functions so that things make more sense, and
remove a lot of confusing casts along the way:
ext4_dirent_csum_verify -> ext4_dirblock_csum_verify
ext4_dirent_csum_set -> ext4_dirblock_csum_set
ext4_dirent_csum -> ext4_dirblock_csum
ext4_handle_dirty_dirent_node -> ext4_handle_dirty_dirblock
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Temporarily cache a casefolded version of the file name under lookup in
ext4_filename, to avoid repeatedly casefolding it. I got up to 30%
speedup on lookups of large directories (>100k entries), depending on
the length of the string under lookup.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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It doesn't make any sense to have project inherit bits
for regular files, even though this won't cause any
problem, but it is better fix this.
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
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Pull fscrypt updates from Ted Ts'o:
"Clean up fscrypt's dcache revalidation support, and other
miscellaneous cleanups"
* tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
fscrypt: cache decrypted symlink target in ->i_link
vfs: use READ_ONCE() to access ->i_link
fscrypt: fix race where ->lookup() marks plaintext dentry as ciphertext
fscrypt: only set dentry_operations on ciphertext dentries
fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory
fscrypt: fix race allowing rename() and link() of ciphertext dentries
fscrypt: clean up and improve dentry revalidation
fscrypt: use READ_ONCE() to access ->i_crypt_info
fscrypt: remove WARN_ON_ONCE() when decryption fails
fscrypt: drop inode argument from fscrypt_get_ctx()
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Add as a feature case-insensitive directories (the casefold feature)
using Unicode 12.1.
Also, the usual largish number of cleanups and bug fixes"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (25 commits)
ext4: export /sys/fs/ext4/feature/casefold if Unicode support is present
ext4: fix ext4_show_options for file systems w/o journal
unicode: refactor the rule for regenerating utf8data.h
docs: ext4.rst: document case-insensitive directories
ext4: Support case-insensitive file name lookups
ext4: include charset encoding information in the superblock
MAINTAINERS: add Unicode subsystem entry
unicode: update unicode database unicode version 12.1.0
unicode: introduce test module for normalized utf8 implementation
unicode: implement higher level API for string handling
unicode: reduce the size of utf8data[]
unicode: introduce code for UTF-8 normalization
unicode: introduce UTF-8 character database
ext4: actually request zeroing of inode table after grow
ext4: cond_resched in work-heavy group loops
ext4: fix use-after-free race with debug_want_extra_isize
ext4: avoid drop reference to iloc.bh twice
ext4: ignore e_value_offs for xattrs with value-in-ea-inode
ext4: protect journal inode's blocks using block_validity
ext4: use BUG() instead of BUG_ON(1)
...
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This patch implements the actual support for case-insensitive file name
lookups in ext4, based on the feature bit and the encoding stored in the
superblock.
A filesystem that has the casefold feature set is able to configure
directories with the +F (EXT4_CASEFOLD_FL) attribute, enabling lookups
to succeed in that directory in a case-insensitive fashion, i.e: match
a directory entry even if the name used by userspace is not a byte per
byte match with the disk name, but is an equivalent case-insensitive
version of the Unicode string. This operation is called a
case-insensitive file name lookup.
The feature is configured as an inode attribute applied to directories
and inherited by its children. This attribute can only be enabled on
empty directories for filesystems that support the encoding feature,
thus preventing collision of file names that only differ by case.
* dcache handling:
For a +F directory, Ext4 only stores the first equivalent name dentry
used in the dcache. This is done to prevent unintentional duplication of
dentries in the dcache, while also allowing the VFS code to quickly find
the right entry in the cache despite which equivalent string was used in
a previous lookup, without having to resort to ->lookup().
d_hash() of casefolded directories is implemented as the hash of the
casefolded string, such that we always have a well-known bucket for all
the equivalencies of the same string. d_compare() uses the
utf8_strncasecmp() infrastructure, which handles the comparison of
equivalent, same case, names as well.
For now, negative lookups are not inserted in the dcache, since they
would need to be invalidated anyway, because we can't trust missing file
dentries. This is bad for performance but requires some leveraging of
the vfs layer to fix. We can live without that for now, and so does
everyone else.
* on-disk data:
Despite using a specific version of the name as the internal
representation within the dcache, the name stored and fetched from the
disk is a byte-per-byte match with what the user requested, making this
implementation 'name-preserving'. i.e. no actual information is lost
when writing to storage.
DX is supported by modifying the hashes used in +F directories to make
them case/encoding-aware. The new disk hashes are calculated as the
hash of the full casefolded string, instead of the string directly.
This allows us to efficiently search for file names in the htree without
requiring the user to provide an exact name.
* Dealing with invalid sequences:
By default, when a invalid UTF-8 sequence is identified, ext4 will treat
it as an opaque byte sequence, ignoring the encoding and reverting to
the old behavior for that unique file. This means that case-insensitive
file name lookup will not work only for that file. An optional bit can
be set in the superblock telling the filesystem code and userspace tools
to enforce the encoding. When that optional bit is set, any attempt to
create a file name using an invalid UTF-8 sequence will fail and return
an error to userspace.
* Normalization algorithm:
The UTF-8 algorithms used to compare strings in ext4 is implemented
lives in fs/unicode, and is based on a previous version developed by
SGI. It implements the Canonical decomposition (NFD) algorithm
described by the Unicode specification 12.1, or higher, combined with
the elimination of ignorable code points (NFDi) and full
case-folding (CF) as documented in fs/unicode/utf8_norm.c.
NFD seems to be the best normalization method for EXT4 because:
- It has a lower cost than NFC/NFKC (which requires
decomposing to NFD as an intermediary step)
- It doesn't eliminate important semantic meaning like
compatibility decompositions.
Although:
- This implementation is not completely linguistic accurate, because
different languages have conflicting rules, which would require the
specialization of the filesystem to a given locale, which brings all
sorts of problems for removable media and for users who use more than
one language.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Support for encoding is considered an incompatible feature, since it has
potential to create collisions of file names in existing filesystems.
If the feature flag is not enabled, the entire filesystem will operate
on opaque byte sequences, respecting the original behavior.
The s_encoding field stores a magic number indicating the encoding
format and version used globally by file and directory names in the
filesystem. The s_encoding_flags defines policies for using the charset
encoding, like how to handle invalid sequences. The magic number is
mapped to the exact charset table, but the mapping is specific to ext4.
Since we don't have any commitment to support old encodings, the only
encoding I am supporting right now is utf8-12.1.0.
The current implementation prevents the user from enabling encoding and
per-directory encryption on the same filesystem at the same time. The
incompatibility between these features lies in how we do efficient
directory searches when we cannot be sure the encryption of the user
provided fname will match the actual hash stored in the disk without
decrypting every directory entry, because of normalization cases. My
quickest solution is to simply block the concurrent use of these
features for now, and enable it later, once we have a better solution.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.
With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP. These would all need to be fixed if any shash algorithm
actually started sleeping. For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API. However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.
Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk. It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.
Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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->lookup() in an encrypted directory begins as follows:
1. fscrypt_prepare_lookup():
a. Try to load the directory's encryption key.
b. If the key is unavailable, mark the dentry as a ciphertext name
via d_flags.
2. fscrypt_setup_filename():
a. Try to load the directory's encryption key.
b. If the key is available, encrypt the name (treated as a plaintext
name) to get the on-disk name. Otherwise decode the name
(treated as a ciphertext name) to get the on-disk name.
But if the key is concurrently added, it may be found at (2a) but not at
(1a). In this case, the dentry will be wrongly marked as a ciphertext
name even though it was actually treated as plaintext.
This will cause the dentry to be wrongly invalidated on the next lookup,
potentially causing problems. For example, if the racy ->lookup() was
part of sys_mount(), then the new mount will be detached when anything
tries to access it. This is despite the mountpoint having a plaintext
path, which should remain valid now that the key was added.
Of course, this is only possible if there's a userspace race. Still,
the additional kernel-side race is confusing and unexpected.
Close the kernel-side race by changing fscrypt_prepare_lookup() to also
set the on-disk filename (step 2b), consistent with the d_flags update.
Fixes: 28b4c263961c ("ext4 crypto: revalidate dentry after adding or removing the key")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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The comment above NEXT_ORPHAN() was meant for ext4_encrypted_inode(),
which was moved by commit a7550b30ab70 ("ext4 crypto: migrate into vfs's
crypto engine") but the comment was accidentally left in place. Since
ext4_encrypted_inode() has now been removed, just remove the comment.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"A large number of bug fixes and cleanups.
One new feature to allow users to more easily find the jbd2 journal
thread for a particular ext4 file system"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (25 commits)
jbd2: jbd2_get_transaction does not need to return a value
jbd2: fix invalid descriptor block checksum
ext4: fix bigalloc cluster freeing when hole punching under load
ext4: add sysfs attr /sys/fs/ext4/<disk>/journal_task
ext4: Change debugging support help prefix from EXT4 to Ext4
ext4: fix compile error when using BUFFER_TRACE
jbd2: fix compile warning when using JBUFFER_TRACE
ext4: fix some error pointer dereferences
ext4: annotate more implicit fall throughs
ext4: annotate implicit fall throughs
ext4: don't update s_rev_level if not required
jbd2: fold jbd2_superblock_csum_{verify,set} into their callers
jbd2: fix race when writing superblock
ext4: fix crash during online resizing
ext4: disallow files with EXT4_JOURNAL_DATA_FL from EXT4_IOC_SWAP_BOOT
ext4: add mask of ext4 flags to swap
ext4: update quota information while swapping boot loader inode
ext4: cleanup pagecache before swap i_data
ext4: fix check of inode in swap_inode_boot_loader
ext4: unlock unused_pages timely when doing writeback
...
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Don't update the superblock s_rev_level during mount if it isn't
actually necessary, only if superblock features are being set by
the kernel. This was originally added for ext3 since it always
set the INCOMPAT_RECOVER and HAS_JOURNAL features during mount,
but this is not needed since no journal mode was added to ext4.
That will allow Geert to mount his 20-year-old ext2 rev 0.0 m68k
filesystem, as a testament of the backward compatibility of ext4.
Fixes: 0390131ba84f ("ext4: Allow ext4 to run without a journal")
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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The reason is that while swapping two inode, we swap the flags too.
Some flags such as EXT4_JOURNAL_DATA_FL can really confuse the things
since we're not resetting the address operations structure. The
simplest way to keep things sane is to restrict the flags that can be
swapped.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
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In order to have a common code base for fscrypt "post read" processing
for all filesystems which support encryption, this commit removes
filesystem specific build config option (e.g. CONFIG_EXT4_FS_ENCRYPTION)
and replaces it with a build option (i.e. CONFIG_FS_ENCRYPTION) whose
value affects all the filesystems making use of fscrypt.
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
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This commit removes the ext4 specific ext4_encrypted_inode() and makes
use of the generic IS_ENCRYPTED() macro to check for the encryption
status of an inode.
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
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If we receive a file handle, either from NFS or open_by_handle_at(2),
and it points at an inode which has not been initialized, and the file
system has metadata checksums enabled, we shouldn't try to get the
inode, discover the checksum is invalid, and then declare the file
system as being inconsistent.
This can be reproduced by creating a test file system via "mke2fs -t
ext4 -O metadata_csum /tmp/foo.img 8M", mounting it, cd'ing into that
directory, and then running the following program.
#define _GNU_SOURCE
#include <fcntl.h>
struct handle {
struct file_handle fh;
unsigned char fid[MAX_HANDLE_SZ];
};
int main(int argc, char **argv)
{
struct handle h = {{8, 1 }, { 12, }};
open_by_handle_at(AT_FDCWD, &h.fh, O_RDONLY);
return 0;
}
Google-Bug-Id: 120690101
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
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Today, when sb_bread() returns NULL, this can either be because of an
I/O error or because the system failed to allocate the buffer. Since
it's an old interface, changing would require changing many call
sites.
So instead we create our own ext4_sb_bread(), which also allows us to
set the REQ_META flag.
Also fixed a problem in the xattr code where a NULL return in a
function could also mean that the xattr was not found, which could
lead to the wrong error getting returned to userspace.
Fixes: ac27a0ec112a ("ext4: initial copy of files from ext3")
Cc: stable@kernel.org # 2.6.19
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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https://github.com/ojeda/linux
Pull compiler attribute updates from Miguel Ojeda:
"This is an effort to disentangle the include/linux/compiler*.h headers
and bring them up to date.
The main idea behind the series is to use feature checking macros
(i.e. __has_attribute) instead of compiler version checks (e.g.
GCC_VERSION), which are compiler-agnostic (so they can be shared,
reducing the size of compiler-specific headers) and version-agnostic.
Other related improvements have been performed in the headers as well,
which on top of the use of __has_attribute it has amounted to a
significant simplification of these headers (e.g. GCC_VERSION is now
only guarding a few non-attribute macros).
This series should also help the efforts to support compiling the
kernel with clang and icc. A fair amount of documentation and comments
have also been added, clarified or removed; and the headers are now
more readable, which should help kernel developers in general.
The series was triggered due to the move to gcc >= 4.6. In turn, this
series has also triggered Sparse to gain the ability to recognize
__has_attribute on its own.
Finally, the __nonstring variable attribute series has been also
applied on top; plus two related patches from Nick Desaulniers for
unreachable() that came a bit afterwards"
* tag 'compiler-attributes-for-linus-4.20-rc1' of https://github.com/ojeda/linux:
compiler-gcc: remove comment about gcc 4.5 from unreachable()
compiler.h: update definition of unreachable()
Compiler Attributes: ext4: remove local __nonstring definition
Compiler Attributes: auxdisplay: panel: use __nonstring
Compiler Attributes: enable -Wstringop-truncation on W=1 (gcc >= 8)
Compiler Attributes: add support for __nonstring (gcc >= 8)
Compiler Attributes: add MAINTAINERS entry
Compiler Attributes: add Doc/process/programming-language.rst
Compiler Attributes: remove uses of __attribute__ from compiler.h
Compiler Attributes: KENTRY used twice the "used" attribute
Compiler Attributes: use feature checks instead of version checks
Compiler Attributes: add missing SPDX ID in compiler_types.h
Compiler Attributes: remove unneeded sparse (__CHECKER__) tests
Compiler Attributes: homogenize __must_be_array
Compiler Attributes: remove unneeded tests
Compiler Attributes: always use the extra-underscores syntax
Compiler Attributes: remove unused attributes
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It's possible for ext4_show_quota_options() to try reading
s_qf_names[i] while it is being modified by ext4_remount() --- most
notably, in ext4_remount's error path when the original values of the
quota file name gets restored.
Reported-by: syzbot+a2872d6feea6918008a9@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 3.2+
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Return type of ext4_page_mkwrite and ext4_filemap_fault are
changed to use vm_fault_t type.
With this patch all the callers of block_page_mkwrite_return()
are changed to handle vm_fault_t. So converting the return type
of block_page_mkwrite_return() to vm_fault_t.
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
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Add new code to count canceled pending cluster reservations on bigalloc
file systems and to reduce the cluster reservation count on all file
systems using delayed allocation. This replaces old code in
ext4_da_page_release_reservations that was incorrect.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Modify ext4_ext_remove_space() and the code it calls to correct the
reserved cluster count for pending reservations (delayed allocated
clusters shared with allocated blocks) when a block range is removed
from the extent tree. Pending reservations may be found for the clusters
at the ends of written or unwritten extents when a block range is removed.
If a physical cluster at the end of an extent is freed, it's necessary
to increment the reserved cluster count to maintain correct accounting
if the corresponding logical cluster is shared with at least one
delayed and unwritten extent as found in the extents status tree.
Add a new function, ext4_rereserve_cluster(), to reapply a reservation
on a delayed allocated cluster sharing blocks with a freed allocated
cluster. To avoid ENOSPC on reservation, a flag is applied to
ext4_free_blocks() to briefly defer updating the freeclusters counter
when an allocated cluster is freed. This prevents another thread
from allocating the freed block before the reservation can be reapplied.
Redefine the partial cluster object as a struct to carry more state
information and to clarify the code using it.
Adjust the conditional code structure in ext4_ext_remove_space to
reduce the indentation level in the main body of the code to improve
readability.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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The code in ext4_da_map_blocks sometimes reserves space for more
delayed allocated clusters than it should, resulting in premature
ENOSPC, exceeded quota, and inaccurate free space reporting.
Fix this by checking for written and unwritten blocks shared in the
same cluster with the newly delayed allocated block. A cluster
reservation should not be made for a cluster for which physical space
has already been allocated.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Add new pending reservation mechanism to help manage reserved cluster
accounting. Its primary function is to avoid the need to read extents
from the disk when invalidating pages as a result of a truncate, punch
hole, or collapse range operation.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore |
