linux-toradex.git/fs/f2fs/dir.c, branch v6.3

f2fs: merge f2fs_show_injection_info() into time_to_inject()

2023-01-11T19:15:19+00:00

There is no need to additionally use f2fs_show_injection_info()
to output information. Concatenate time_to_inject() and
__time_to_inject() via a macro. In the new __time_to_inject()
function, pass in the caller function name and parent function.

In this way, we no longer need the f2fs_show_injection_info() function,
and let's remove it.

Suggested-by: Chao Yu 
Signed-off-by: Yangtao Li 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: change type for 'sbi->readdir_ra'

2022-11-28T20:46:33+00:00

Before this patch, the varibale 'readdir_ra' takes effect if it's equal
to '1' or not, so we can change type for it from 'int' to 'bool'.

Signed-off-by: Yuwei Guan 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: optimize iteration over sparse directories

2022-11-11T17:48:24+00:00

Wei Chen reports a kernel bug as blew:

INFO: task syz-executor.0:29056 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc5 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:14632 pid:29056 ppid:  6574 flags:0x00000004
Call Trace:
 __schedule+0x4a1/0x1720
 schedule+0x36/0xe0
 rwsem_down_write_slowpath+0x322/0x7a0
 fscrypt_ioctl_set_policy+0x11f/0x2a0
 __f2fs_ioctl+0x1a9f/0x5780
 f2fs_ioctl+0x89/0x3a0
 __x64_sys_ioctl+0xe8/0x140
 do_syscall_64+0x34/0xb0
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Eric did some investigation on this issue, quoted from reply of Eric:

"Well, the quality of this bug report has a lot to be desired (not on
upstream kernel, reproducer is full of totally irrelevant stuff, not
sent to the mailing list of the filesystem whose disk image is being
fuzzed, etc.).  But what is going on is that f2fs_empty_dir() doesn't
consider the case of a directory with an extremely large i_size on a
malicious disk image.

Specifically, the reproducer mounts an f2fs image with a directory
that has an i_size of 14814520042850357248, then calls
FS_IOC_SET_ENCRYPTION_POLICY on it.

That results in a call to f2fs_empty_dir() to check whether the
directory is empty.  f2fs_empty_dir() then iterates through all
3616826182336513 blocks the directory allegedly contains to check
whether any contain anything.  i_rwsem is held during this, so
anything else that tries to take it will hang."

In order to solve this issue, let's use f2fs_get_next_page_offset()
to speed up iteration by skipping holes for all below functions:
- f2fs_empty_dir
- f2fs_readdir
- find_in_level

The way why we can speed up iteration was described in
'commit 3cf4574705b4 ("f2fs: introduce get_next_page_offset to speed
up SEEK_DATA")'.

Meanwhile, in f2fs_empty_dir(), let's use f2fs_find_data_page()
instead f2fs_get_lock_data_page(), due to i_rwsem was held in
caller of f2fs_empty_dir(), there shouldn't be any races, so it's
fine to not lock dentry page during lookuping dirents in the page.

Link: https://lore.kernel.org/lkml/536944df-a0ae-1dd8-148f-510b476e1347@kernel.org/T/
Reported-by: Wei Chen 
Cc: Eric Biggers 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: support recording errors into superblock

2022-10-04T20:31:45+00:00

This patch supports to record detail reason of FSCORRUPTED error into
f2fs_super_block.s_errors[].

Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: don't use casefolded comparison for "." and ".."

2022-05-17T18:19:23+00:00

Tryng to rename a directory that has all following properties fails with
EINVAL and triggers the 'WARN_ON_ONCE(!fscrypt_has_encryption_key(dir))'
in f2fs_match_ci_name():

    - The directory is casefolded
    - The directory is encrypted
    - The directory's encryption key is not yet set up
    - The parent directory is *not* encrypted

The problem is incorrect handling of the lookup of ".." to get the
parent reference to update.  fscrypt_setup_filename() treats ".." (and
".") specially, as it's never encrypted.  It's passed through as-is, and
setting up the directory's key is not attempted.  As the name isn't a
no-key name, f2fs treats it as a "normal" name and attempts a casefolded
comparison.  That breaks the assumption of the WARN_ON_ONCE() in
f2fs_match_ci_name() which assumes that for encrypted directories,
casefolded comparisons only happen when the directory's key is set up.

We could just remove this WARN_ON_ONCE().  However, since casefolding is
always a no-op on "." and ".." anyway, let's instead just not casefold
these names.  This results in the standard bytewise comparison.

Fixes: 7ad08a58bf67 ("f2fs: Handle casefolding with Encryption")
Cc:  # v5.11+
Signed-off-by: Eric Biggers 
Reviewed-by: Gabriel Krisman Bertazi 
Signed-off-by: Jaegeuk Kim

Merge tag 'f2fs-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

2022-03-22T17:00:31+00:00

Pull f2fs updates from Jaegeuk Kim:
 "In this cycle, f2fs has some performance improvements for Android
  workloads such as using read-unfair rwsems and adding some sysfs
  entries to control GCs and discard commands in more details. In
  addtiion, it has some tunings to improve the recovery speed after
  sudden power-cut.

  Enhancement:
   - add reader-unfair rwsems with F2FS_UNFAIR_RWSEM: will replace with
     generic API support
   - adjust to make the readahead/recovery flow more efficiently
   - sysfs entries to control issue speeds of GCs and Discard commands
   - enable idmapped mounts

  Bug fix:
   - correct wrong error handling routines
   - fix missing conditions in quota
   - fix a potential deadlock between writeback and block plug routines
   - fix a deadlock btween freezefs and evict_inode

  We've added some boundary checks to avoid kernel panics on corrupted
  images, and several minor code clean-ups"

* tag 'f2fs-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (27 commits)
  f2fs: fix to do sanity check on .cp_pack_total_block_count
  f2fs: make gc_urgent and gc_segment_mode sysfs node readable
  f2fs: use aggressive GC policy during f2fs_disable_checkpoint()
  f2fs: fix compressed file start atomic write may cause data corruption
  f2fs: initialize sbi->gc_mode explicitly
  f2fs: introduce gc_urgent_mid mode
  f2fs: compress: fix to print raw data size in error path of lz4 decompression
  f2fs: remove redundant parameter judgment
  f2fs: use spin_lock to avoid hang
  f2fs: don't get FREEZE lock in f2fs_evict_inode in frozen fs
  f2fs: remove unnecessary read for F2FS_FITS_IN_INODE
  f2fs: introduce F2FS_UNFAIR_RWSEM to support unfair rwsem
  f2fs: avoid an infinite loop in f2fs_sync_dirty_inodes
  f2fs: fix to do sanity check on curseg->alloc_type
  f2fs: fix to avoid potential deadlock
  f2fs: quota: fix loop condition at f2fs_quota_sync()
  f2fs: Restore rwsem lockdep support
  f2fs: fix missing free nid in f2fs_handle_failed_inode
  f2fs: support idmapped mounts
  f2fs: add a way to limit roll forward recovery time
  ...

f2fs: move f2fs to use reader-unfair rwsems

2022-01-25T01:40:04+00:00

f2fs rw_semaphores work better if writers can starve readers,
especially for the checkpoint thread, because writers are strictly
more important than reader threads. This prevents significant priority
inversion between low-priority readers that blocked while trying to
acquire the read lock and a second acquisition of the write lock that
might be blocking high priority work.

Signed-off-by: Tim Murray 
Signed-off-by: Jaegeuk Kim

unicode: clean up the Kconfig symbol confusion

2022-01-21T00:57:24+00:00

Turn the CONFIG_UNICODE symbol into a tristate that generates some always
built in code and remove the confusing CONFIG_UNICODE_UTF8_DATA symbol.

Note that a lot of the IS_ENABLED() checks could be turned from cpp
statements into normal ifs, but this change is intended to be fairly
mechanic, so that should be cleaned up later.

Fixes: 2b3d04787012 ("unicode: Add utf8-data module")
Reported-by: Linus Torvalds 
Reviewed-by: Eric Biggers 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Gabriel Krisman Bertazi

f2fs: support fault injection for f2fs_kmem_cache_alloc()

2021-08-17T18:59:05+00:00

This patch supports to inject fault into f2fs_kmem_cache_alloc().

Usage:
a) echo 32768 > /sys/fs/f2fs//inject_type or
b) mount -o fault_type=32768  

Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: reduce the scope of setting fsck tag when de->name_len is zero

2021-08-04T22:51:21+00:00

I recently found a case where de->name_len is 0 in f2fs_fill_dentries()
easily reproduced, and finally set the fsck flag.

Thread A			Thread B
- f2fs_readdir
 - f2fs_read_inline_dir
  - ctx->pos = d.max
				- f2fs_add_dentry
				 - f2fs_add_inline_entry
				  - do_convert_inline_dir
				 - f2fs_add_regular_entry
- f2fs_readdir
 - f2fs_fill_dentries
  - set_sbi_flag(sbi, SBI_NEED_FSCK)

Process A opens the folder, and has been reading without closing it.
During this period, Process B created a file under the folder (occupying
multiple f2fs_dir_entry, exceeding the d.max of the inline dir). After
creation, process A uses the d.max of inline dir to read it again, and
it will read that de->name_len is 0.

And Chao pointed out that w/o inline conversion, the race condition still
can happen as below:

dir_entry1: A
dir_entry2: B
dir_entry3: C
free slot: _
ctx->pos: ^

Thread A is traversing directory,
ctx-pos moves to below position after readdir() by thread A:
AAAABBBB___
        ^

Then thread B delete dir_entry2, and create dir_entry3.

Thread A calls readdir() to lookup dirents starting from middle
of new dirent slots as below:
AAAACCCCCC_
        ^
In these scenarios, the file system is not damaged, and it's hard to
avoid it. But we can bypass tagging FSCK flag if:
a) bit_pos (:= ctx->pos % d->max) is non-zero and
b) before bit_pos moves to first valid dir_entry.

Fixes: ddf06b753a85 ("f2fs: fix to trigger fsck if dirent.name_len is zero")
Signed-off-by: Yangtao Li 
[Chao: clean up description]
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim