Expand f2fs's casefolding support to include encrypted directories. To
index casefolded+encrypted directories, we use the SipHash of the
casefolded name, keyed by a key derived from the directory's fscrypt
master key. This ensures that the dirhash doesn't leak information
about the plaintext filenames.
Encryption keys are unavailable during roll-forward recovery, so we
can't compute the dirhash when recovering a new dentry in an encrypted +
casefolded directory. To avoid having to force a checkpoint when a new
file is fsync'ed, store the dirhash on-disk appended to i_name.
This patch incorporates work by Eric Biggers <ebiggers@google.com>
and Jaegeuk Kim <jaegeuk@kernel.org>.
Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
In this round, we've added some knobs to enhance compression feature and harden
testing environment. In addition, we've fixed several bugs reported from Android
devices such as long discarding latency, device hanging during quota_sync, etc.
Enhancement:
- support lzo-rle algorithm
- add two ioctls to release and reserve blocks for compression
- support partial truncation/fiemap on compressed file
- introduce sysfs entries to attach IO flags explicitly
- add iostat trace point along with read io stat
Bug fix:
- fix long discard latency
- flush quota data by f2fs_quota_sync correctly
- fix to recover parent inode number for power-cut recovery
- fix lz4/zstd output buffer budget
- parse checkpoint mount option correctly
- avoid inifinite loop to wait for flushing node/meta pages
- manage discard space correctly
And some refactoring and clean up patches were added.
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Merge tag 'f2fs-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, we've added some knobs to enhance compression feature
and harden testing environment. In addition, we've fixed several bugs
reported from Android devices such as long discarding latency, device
hanging during quota_sync, etc.
Enhancements:
- support lzo-rle algorithm
- add two ioctls to release and reserve blocks for compression
- support partial truncation/fiemap on compressed file
- introduce sysfs entries to attach IO flags explicitly
- add iostat trace point along with read io stat
Bug fixes:
- fix long discard latency
- flush quota data by f2fs_quota_sync correctly
- fix to recover parent inode number for power-cut recovery
- fix lz4/zstd output buffer budget
- parse checkpoint mount option correctly
- avoid inifinite loop to wait for flushing node/meta pages
- manage discard space correctly
And some refactoring and clean up patches were added"
* tag 'f2fs-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (51 commits)
f2fs: attach IO flags to the missing cases
f2fs: add node_io_flag for bio flags likewise data_io_flag
f2fs: remove unused parameter of f2fs_put_rpages_mapping()
f2fs: handle readonly filesystem in f2fs_ioc_shutdown()
f2fs: avoid utf8_strncasecmp() with unstable name
f2fs: don't return vmalloc() memory from f2fs_kmalloc()
f2fs: fix retry logic in f2fs_write_cache_pages()
f2fs: fix wrong discard space
f2fs: compress: don't compress any datas after cp stop
f2fs: remove unneeded return value of __insert_discard_tree()
f2fs: fix wrong value of tracepoint parameter
f2fs: protect new segment allocation in expand_inode_data
f2fs: code cleanup by removing ifdef macro surrounding
f2fs: avoid inifinite loop to wait for flushing node pages at cp_error
f2fs: flush dirty meta pages when flushing them
f2fs: fix checkpoint=disable:%u%%
f2fs: compress: fix zstd data corruption
f2fs: add compressed/gc data read IO stat
f2fs: fix potential use-after-free issue
f2fs: compress: don't handle non-compressed data in workqueue
...
Rework f2fs's handling of filenames to use a new 'struct f2fs_filename'.
Similar to 'struct ext4_filename', this stores the usr_fname, disk_name,
dirhash, crypto_buf, and casefolded name. Some of these names can be
NULL in some cases. 'struct f2fs_filename' differs from
'struct fscrypt_name' mainly in that the casefolded name is included.
For user-initiated directory operations like lookup() and create(),
initialize the f2fs_filename by translating the corresponding
fscrypt_name, then computing the dirhash and casefolded name if needed.
This makes the dirhash and casefolded name be cached for each syscall,
so we don't have to recompute them repeatedly. (Previously, f2fs
computed the dirhash once per directory level, and the casefolded name
once per directory block.) This improves performance.
This rework also makes it much easier to correctly handle all
combinations of normal, encrypted, casefolded, and encrypted+casefolded
directories. (The fourth isn't supported yet but is being worked on.)
The only other cases where an f2fs_filename gets initialized are for two
filesystem-internal operations: (1) when converting an inline directory
to a regular one, we grab the needed disk_name and hash from an existing
f2fs_dir_entry; and (2) when roll-forward recovering a new dentry, we
grab the needed disk_name from f2fs_inode::i_name and compute the hash.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
<linux/cryptohash.h> sounds very generic and important, like it's the
header to include if you're doing cryptographic hashing in the kernel.
But actually it only includes the library implementation of the SHA-1
compression function (not even the full SHA-1). This should basically
never be used anymore; SHA-1 is no longer considered secure, and there
are much better ways to do cryptographic hashing in the kernel.
Most files that include this header don't actually need it. So in
preparation for removing it, remove all these unneeded includes of it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Modeled after commit b886ee3e77 ("ext4: Support case-insensitive file
name lookups")
"""
This patch implements the actual support for case-insensitive file name
lookups in f2fs, 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 (F2FS_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, F2Fs 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 f2fs is implemented
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 F2FS 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: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Remove the verbose license text from f2fs files and replace them with
SPDX tags. This does not change the license of any of the code.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
If user has no key under an encrypted dir, fscrypt gives digested dentries.
Previously, when looking up a dentry, f2fs only checks its hash value with
first 4 bytes of the digested dentry, which didn't handle hash collisions fully.
This patch enhances to check entire dentry bytes likewise ext4.
Eric reported how to reproduce this issue by:
# seq -f "edir/abcdefghijklmnopqrstuvwxyz012345%.0f" 100000 | xargs touch
# find edir -type f | xargs stat -c %i | sort | uniq | wc -l
100000
# sync
# echo 3 > /proc/sys/vm/drop_caches
# keyctl new_session
# find edir -type f | xargs stat -c %i | sort | uniq | wc -l
99999
Cc: <stable@vger.kernel.org>
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
(fixed f2fs_dentry_hash() to work even when the hash is 0)
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The dentry name type is unsigned char *.
If we don't match this type, some character codes can be changed by signed bit.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch is intended to unify string length declarations and usage.
There are number of calls to strlen which return size_t object.
The size of this object depends on compiler if it will be bigger,
equal or even smaller than an unsigned int
Signed-off-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Test Case:
[NFS Client]
ls -lR .
[NFS Server]
while [ 1 ]
do
echo 3 > /proc/sys/vm/drop_caches
done
Error on NFS Client: "No such file or directory"
When cache is dropped at the server, it results in lookup failure at the
NFS client due to non-connection with the parent. The default path is it
initiates a lookup by calculating the hash value for the name, even though
the hash values stored on the disk for "." and ".." is maintained as zero,
which results in failure from find_in_block due to not matching HASH values.
Fix up, by using the correct hashing values for these entries.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
As pointed out by Randy Dunlap, this patch removes all usage of "/**" for comment
blocks. Instead, just use "/*".
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This patch should resolve the bugs reported by the sparse tool.
Initial reports were written by "kbuild test robot" managed by fengguang.wu.
In my local machines, I've tested also by running:
> make C=2 CF="-D__CHECK_ENDIAN__"
Accordingly, I've found lots of warnings and bugs related to the endian
conversion. And I've fixed all at this moment.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Daniel Rosenberg