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  1. 12 5月, 2020 2 次提交
    • E
      f2fs: rework filename handling · 43c780ba
      由 Eric Biggers 提交于 
      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: NEric Biggers <ebiggers@google.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      43c780ba
    • E
      f2fs: split f2fs_d_compare() from f2fs_match_name() · f874fa1c
      由 Eric Biggers 提交于 
      Sharing f2fs_ci_compare() between comparing cached dentries
(f2fs_d_compare()) and comparing on-disk dentries (f2fs_match_name())
doesn't work as well as intended, as these actions fundamentally differ
in several ways (e.g. whether the task may sleep, whether the directory
is stable, whether the casefolded name was precomputed, whether the
dentry will need to be decrypted once we allow casefold+encrypt, etc.)

Just make f2fs_d_compare() implement what it needs directly, and rework
f2fs_ci_compare() to be specialized for f2fs_match_name().
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      f874fa1c
  3. 31 3月, 2020 2 次提交
  5. 25 1月, 2020 2 次提交
    • E
      f2fs: fix race conditions in ->d_compare() and ->d_hash() · 80f2388a
      由 Eric Biggers 提交于 
      Since ->d_compare() and ->d_hash() can be called in RCU-walk mode,
->d_parent and ->d_inode can be concurrently modified, and in
particular, ->d_inode may be changed to NULL.  For f2fs_d_hash() this
resulted in a reproducible NULL dereference if a lookup is done in a
directory being deleted, e.g. with:

	int main()
	{
		if (fork()) {
			for (;;) {
				mkdir("subdir", 0700);
				rmdir("subdir");
			}
		} else {
			for (;;)
				access("subdir/file", 0);
		}
	}

... or by running the 't_encrypted_d_revalidate' program from xfstests.
Both repros work in any directory on a filesystem with the encoding
feature, even if the directory doesn't actually have the casefold flag.

I couldn't reproduce a crash in f2fs_d_compare(), but it appears that a
similar crash is possible there.

Fix these bugs by reading ->d_parent and ->d_inode using READ_ONCE() and
falling back to the case sensitive behavior if the inode is NULL.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Fixes: 2c2eb7a3 ("f2fs: Support case-insensitive file name lookups")
Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      80f2388a
    • E
      f2fs: fix dcache lookup of !casefolded directories · 5515eae6
      由 Eric Biggers 提交于 
      Do the name comparison for non-casefolded directories correctly.

This is analogous to ext4's commit 66883da1 ("ext4: fix dcache
lookup of !casefolded directories").

Fixes: 2c2eb7a3 ("f2fs: Support case-insensitive file name lookups")
Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      5515eae6
  7. 18 1月, 2020 1 次提交
  9. 01 1月, 2020 1 次提交
  11. 20 11月, 2019 1 次提交
  13. 16 9月, 2019 1 次提交
    • C
      f2fs: fix to avoid accessing uninitialized field of inode page in is_alive() · 98194030
      由 Chao Yu 提交于 
      If inode is newly created, inode page may not synchronize with inode cache,
so fields like .i_inline or .i_extra_isize could be wrong, in below call
path, we may access such wrong fields, result in failing to migrate valid
target block.

Thread A				Thread B
- f2fs_create
 - f2fs_add_link
  - f2fs_add_dentry
   - f2fs_init_inode_metadata
    - f2fs_add_inline_entry
     - f2fs_new_inode_page
     - f2fs_put_page
     : inode page wasn't updated with inode cache
					- gc_data_segment
					 - is_alive
					  - f2fs_get_node_page
					  - datablock_addr
					   - offset_in_addr
					   : access uninitialized fields

Fixes: 7a2af766 ("f2fs: enhance on-disk inode structure scalability")
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      98194030
  15. 07 9月, 2019 1 次提交
  17. 23 8月, 2019 2 次提交
    • C
      f2fs: introduce f2fs_match_name() for cleanup · fe76a166
      由 Chao Yu 提交于 
      This patch introduces f2fs_match_name() for cleanup.

BTW, it avoids to fallback to normal comparison once it doesn't
match casefolded name.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      fe76a166
    • D
      f2fs: Support case-insensitive file name lookups · 2c2eb7a3
      由 Daniel Rosenberg 提交于 
      Modeled after commit b886ee3e ("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: NDaniel Rosenberg <drosen@google.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      2c2eb7a3
  19. 03 7月, 2019 2 次提交
  21. 31 5月, 2019 1 次提交
  23. 13 3月, 2019 2 次提交
  25. 24 1月, 2019 1 次提交
  27. 23 1月, 2019 2 次提交
  29. 27 12月, 2018 1 次提交
  31. 27 11月, 2018 1 次提交
  33. 23 10月, 2018 1 次提交
  35. 21 10月, 2018 1 次提交
  37. 17 10月, 2018 1 次提交
  39. 13 9月, 2018 1 次提交
  41. 12 9月, 2018 1 次提交
  43. 15 8月, 2018 1 次提交
    • A
      f2fs: rework fault injection handling to avoid a warning · 7fa750a1
      由 Arnd Bergmann 提交于 
      When CONFIG_F2FS_FAULT_INJECTION is disabled, we get a warning about an
unused label:

fs/f2fs/segment.c: In function '__submit_discard_cmd':
fs/f2fs/segment.c:1059:1: error: label 'submit' defined but not used [-Werror=unused-label]

This could be fixed by adding another #ifdef around it, but the more
reliable way of doing this seems to be to remove the other #ifdefs
where that is easily possible.

By defining time_to_inject() as a trivial stub, most of the checks for
CONFIG_F2FS_FAULT_INJECTION can go away. This also leads to nicer
formatting of the code.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      7fa750a1
  45. 01 6月, 2018 3 次提交
    • C
      f2fs: clean up symbol namespace · 4d57b86d
      由 Chao Yu 提交于 
      As Ted reported:

"Hi, I was looking at f2fs's sources recently, and I noticed that there
is a very large number of non-static symbols which don't have a f2fs
prefix.  There's well over a hundred (see attached below).

As one example, in fs/f2fs/dir.c there is:

unsigned char get_de_type(struct f2fs_dir_entry *de)

This function is clearly only useful for f2fs, but it has a generic
name.  This means that if any other file system tries to have the same
symbol name, there will be a symbol conflict and the kernel would not
successfully build.  It also means that when someone is looking f2fs
sources, it's not at all obvious whether a function such as
read_data_page(), invalidate_blocks(), is a generic kernel function
found in the fs, mm, or block layers, or a f2fs specific function.

You might want to fix this at some point.  Hopefully Kent's bcachefs
isn't similarly using genericly named functions, since that might
cause conflicts with f2fs's functions --- but just as this would be a
problem that we would rightly insist that Kent fix, this is something
that we should have rightly insisted that f2fs should have fixed
before it was integrated into the mainline kernel.

acquire_orphan_inode
add_ino_entry
add_orphan_inode
allocate_data_block
allocate_new_segments
alloc_nid
alloc_nid_done
alloc_nid_failed
available_free_memory
...."

This patch adds "f2fs_" prefix for all non-static symbols in order to:
a) avoid conflict with other kernel generic symbols;
b) to indicate the function is f2fs specific one instead of generic
one;
Reported-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      4d57b86d
    • C
      f2fs: make set_de_type() static · 2e79d951
      由 Chao Yu 提交于 
      Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      2e79d951
    • C
      f2fs: clean up with clear_radix_tree_dirty_tag · aec2f729
      由 Chao Yu 提交于 
      Introduce clear_radix_tree_dirty_tag to include common codes for cleanup.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
      aec2f729
  47. 12 4月, 2018 1 次提交
  49. 17 3月, 2018 4 次提交
  51. 13 3月, 2018 1 次提交
  53. 03 1月, 2018 2 次提交