exfat: remove unused functions

exfat_count_ext_entries() is no longer called, remove it.
exfat_update_dir_chksum() is no longer called, remove it and
rename exfat_update_dir_chksum_with_entry_set() to it.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: convert exfat_init_ext_entry() to use dentry cache

Before this conversion, in exfat_init_ext_entry(), to init
the dentries in a dentry set, the sync times is equals the
dentry number if 'dirsync' or 'sync' is enabled.
That affects not only performance but also device life.

After this conversion, only needs to be synchronized once if
'dirsync' or 'sync' is enabled.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: move free cluster out of exfat_init_ext_entry()

exfat_init_ext_entry() is an init function, it's a bit strange
to free cluster in it. And the argument 'inode' will be removed
from exfat_init_ext_entry(). So this commit changes to free the
cluster in exfat_remove_entries().

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: convert exfat_remove_entries() to use dentry cache

Before this conversion, in exfat_remove_entries(), to mark the
dentries in a dentry set as deleted, the sync times is equals
the dentry numbers if 'dirsync' or 'sync' is enabled.
That affects not only performance but also device life.

After this conversion, only needs to be synchronized once if
'dirsync' or 'sync' is enabled.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: convert exfat_add_entry() to use dentry cache

After this conversion, if "dirsync" or "sync" is enabled, the
number of synchronized dentries in exfat_add_entry() will change
from 2 to 1.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: add exfat_get_empty_dentry_set() helper

This helper is used to lookup empty dentry set. If there are
no enough empty dentries at the input location, this helper will
return the number of dentries that need to be skipped for the
next lookup.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: add __exfat_get_dentry_set() helper

Since exfat_get_dentry_set() invokes the validate functions of
exfat_validate_entry(), it only supports getting a directory
entry set of an existing file, doesn't support getting an empty
entry set.

To remove the limitation, add this helper.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: support create zero-size directory

This commit adds mount option 'zero_size_dir'. If this option
enabled, don't allocate a cluster to directory when creating
it, and set the directory size to 0.

On Windows, a cluster is allocated for a directory when it is
created, so the mount option is disabled by default.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: add ioctls for accessing attributes

Add GET and SET attributes ioctls to enable attribute modification.
We already do this in FAT and a few userspace utils made for it would
benefit from this also working on exFAT, namely fatattr.

Signed-off-by: Jan Cincera <hcincera@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

vfs: get rid of old '->iterate' directory operation

All users now just use '->iterate_shared()', which only takes the
directory inode lock for reading.

Filesystems that never got convered to shared mode now instead use a
wrapper that drops the lock, re-takes it in write mode, calls the old
function, and then downgrades the lock back to read mode.

This way the VFS layer and other callers no longer need to care about
filesystems that never got converted to the modern era.

The filesystems that use the new wrapper are ceph, coda, exfat, jfs,
ntfs, ocfs2, overlayfs, and vboxsf.

Honestly, several of them look like they really could just iterate their
directories in shared mode and skip the wrapper entirely, but the point
of this change is to not change semantics or fix filesystems that
haven't been fixed in the last 7+ years, but to finally get rid of the
dual iterators.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

exfat: release s_lock before calling dir_emit()

There is a potential deadlock reported by syzbot as below:

======================================================
WARNING: possible circular locking dependency detected
6.4.0-next-20230707-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor330/5073 is trying to acquire lock:
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:151 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5293 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x369/0x510 mm/memory.c:5344
but task is already holding lock:
ffff888019f760e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_iterate+0x117/0xb50 fs/exfat/dir.c:232

which lock already depends on the new lock.

Chain exists of:
&mm->mmap_lock --> mapping.invalidate_lock#3 --> &sbi->s_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sbi->s_lock);
lock(mapping.invalidate_lock#3);
lock(&sbi->s_lock);
rlock(&mm->mmap_lock);

Let's try to avoid above potential deadlock condition by moving dir_emit*()
out of sbi->s_lock coverage.

Fixes: ca06197382bd ("exfat: add directory operations")
Cc: stable@vger.kernel.org #v5.7+
Reported-by: syzbot+1741a5d9b79989c10bdc@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/00000000000078ee7e060066270b@google.com/T/#u
Tested-by: syzbot+1741a5d9b79989c10bdc@syzkaller.appspotmail.com
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: check if filename entries exceeds max filename length

exfat_extract_uni_name copies characters from a given file name entry into
the 'uniname' variable. This variable is actually defined on the stack of
the exfat_readdir() function. According to the definition of
the 'exfat_uni_name' type, the file name should be limited 255 characters
(+ null teminator space), but the exfat_get_uniname_from_ext_entry()
function can write more characters because there is no check if filename
entries exceeds max filename length. This patch add the check not to copy
filename characters when exceeding max filename length.

Cc: stable@vger.kernel.org
Cc: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: handle unreconized benign secondary entries

Sony PXW-Z280 camera add vendor allocation entries to directory of
pictures. Currently, linux exfat does not support it and the file is
not visible. This patch handle vendor extension and allocation entries
as unreconized benign secondary entries. As described in the specification,
it is recognized but ignored, and when deleting directory entry set,
the associated clusters allocation are removed as well as benign secondary
directory entries.

Reported-by: Barócsi Dénes <admin@tveger.hu>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: fix reporting fs error when reading dir beyond EOF

Since seekdir() does not check whether the position is valid, the
position may exceed the size of the directory. We found that for
a directory with discontinuous clusters, if the position exceeds
the size of the directory and the excess size is greater than or
equal to the cluster size, exfat_readdir() will return -EIO,
causing a file system error and making the file system unavailable.

Reproduce this bug by:

seekdir(dir, dir_size + cluster_size);
dirent = readdir(dir);

The following log will be printed if mount with 'errors=remount-ro'.

[11166.712896] exFAT-fs (sdb1): error, invalid access to FAT (entry 0xffffffff)
[11166.712905] exFAT-fs (sdb1): Filesystem has been set read-only

Fixes: 1e5654de0f51 ("exfat: handle wrong stream entry size in exfat_readdir()")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: fix unexpected EOF while reading dir

If the position is not aligned with the dentry size, the return
value of readdir() will be NULL and errno is 0, which means the
end of the directory stream is reached.

If the position is aligned with dentry size, but there is no file
or directory at the position, exfat_readdir() will continue to
get dentry from the next dentry. So the dentry gotten by readdir()
may not be at the position.

After this commit, if the position is not aligned with the dentry
size, round the position up to the dentry size and continue to get
the dentry.

Fixes: ca06197382bd ("exfat: add directory operations")
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: reuse exfat_find_location() to simplify exfat_get_dentry_set()

In exfat_get_dentry_set(), part of the code is the same as
exfat_find_location(), reuse exfat_find_location() to simplify
exfat_get_dentry_set().

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: remove unnecessary arguments from exfat_find_dir_entry()

This commit removes argument 'num_entries' and 'type' from
exfat_find_dir_entry().

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: remove call ilog2() from exfat_readdir()

There is no need to call ilog2() for the conversions between
cluster and dentry in exfat_readdir(), because these conversions
can be replaced with EXFAT_DEN_TO_CLU()/EXFAT_CLU_TO_DEN().

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: replace magic numbers with Macros

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: rename exfat_free_dentry_set() to exfat_put_dentry_set()

Since struct exfat_entry_set_cache is allocated from stack,
no need to free, so rename exfat_free_dentry_set() to
exfat_put_dentry_set(). After renaming, the new function pair
is exfat_get_dentry_set()/exfat_put_dentry_set().

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: move exfat_entry_set_cache from heap to stack

The size of struct exfat_entry_set_cache is only 56 bytes on
64-bit system, and allocating from stack is more efficient than
allocating from heap.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: support dynamic allocate bh for exfat_entry_set_cache

In special cases, a file or a directory may occupied more than 19
directory entries, pre-allocating 3 bh is not enough. Such as
- Support vendor secondary directory entry in the future.
- Since file directory entry is damaged, the SecondaryCount
field is bigger than 18.

So this commit supports dynamic allocation of bh.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: hint the empty entry which at the end of cluster chain

After traversing all directory entries, hint the empty directory
entry no matter whether or not there are enough empty directory
entries.

After this commit, hint the empty directory entries like this:

1. Hint the deleted directory entries if enough;
2. Hint the deleted and unused directory entries which at the
end of the cluster chain no matter whether enough or not(Add
by this commit);
3. If no any empty directory entries, hint the empty directory
entries in the new cluster(Add by this commit).

This avoids repeated traversal of directory entries, reduces CPU
usage, and improves the performance of creating files and
directories(especially on low-performance CPUs).

Test create 5000 files in a class 4 SD card on imx6q-sabrelite
with:

for ((i=0;i<5;i++)); do
sync
time (for ((j=1;j<=1000;j++)); do touch file$((i*1000+j)); done)
done

The more files, the more performance improvements.

Before After Improvement
1~1000 25.360s 22.168s 14.40%
1001~2000 38.242s 28.72ss 33.15%
2001~3000 49.134s 35.037s 40.23%
3001~4000 62.042s 41.624s 49.05%
4001~5000 73.629s 46.772s 57.42%

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: simplify empty entry hint

This commit adds exfat_set_empty_hint()/exfat_reset_empty_hint()
to reduce code complexity and make code more readable.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat_iterate(): don't open-code file_inode(file)

and it's file, not filp...

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

exfat: remove argument 'sector' from exfat_get_dentry()

No any function uses argument 'sector', remove it.

Reviewed-by: Andy.Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama, Wataru <wataru.aoyama@sony.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Yuezhang.Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: make exfat_find_location() static

Make exfat_find_location() static.

Signed-off-by: Christophe Vu-Brugier <christophe.vu-brugier@seagate.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: fix typos in comments

Fix typos in comments.

Signed-off-by: Christophe Vu-Brugier <christophe.vu-brugier@seagate.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: handle wrong stream entry size in exfat_readdir()

The compatibility issue between linux exfat and exfat of some camera
company was reported from Florian. In their exfat, if the number of files
exceeds any limit, the DataLength in stream entry of the directory is
no longer updated. So some files created from camera does not show in
linux exfat. because linux exfat doesn't allow that cpos becomes larger
than DataLength of stream entry. This patch check DataLength in stream
entry only if the type is ALLOC_NO_FAT_CHAIN and add the check ensure
that dentry offset does not exceed max dentries size(256 MB) to avoid
the circular FAT chain issue.

Fixes: ca06197382bd ("exfat: add directory operations")
Cc: stable@vger.kernel.org # v5.9
Reported-by: Florian Cramer <flrncrmr@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Tested-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: speed up iterate/lookup by fixing start point of traversing cluster chain

When directory iterate and lookup is called, there's a buggy rewinding
of start point for traversing cluster chain to the parent directory
entry's first cluster. This caused repeated cluster chain traversing
from the first entry of the parent directory that would show worse
performance if huge amounts of files exist under the parent directory.
Fix not to rewind, make continue from currently referenced cluster and
dir entry.

Tested with 50,000 files under single directory / 256GB sdcard,
with command "time ls -l > /dev/null",
Before : 0m08.69s real 0m00.27s user 0m05.91s system
After : 0m07.01s real 0m00.25s user 0m04.34s system

Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: improve write performance when dirsync enabled

Degradation of write speed caused by frequent disk access for cluster
bitmap update on every cluster allocation could be improved by
selective syncing bitmap buffer. Change to flush bitmap buffer only
for the directory related operations.

Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: add support ioctl and FITRIM function

Add FITRIM ioctl to enable discarding unused blocks while mounted.
As current exFAT doesn't have generic ioctl handler, add empty ioctl
function first, and add FITRIM handler.

Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: remove 'rwoffset' in exfat_inode_info

Remove 'rwoffset' in exfat_inode_info and replace it with the parameter of
exfat_readdir().
Since rwoffset is referenced only by exfat_readdir(), it is not necessary
a exfat_inode_info's member.
Also, change cpos to point to the next of entry-set, and return the index
of dir-entry via dir_entry->entry.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: replace memcpy with structure assignment

Use structure assignment instead of memcpy.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: eliminate dead code in exfat_find()

The exfat_find_dir_entry() called by exfat_find() doesn't return -EEXIST.
Therefore, the root-dir information setting is never executed.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: add error check when updating dir-entries

Add error check when synchronously updating dir-entries.

Suggested-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: write multiple sectors at once

Write multiple sectors at once when updating dir-entries.
Add exfat_update_bhs() for that. It wait for write completion once
instead of sector by sector.
It's only effective if sync enabled.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: remove EXFAT_SB_DIRTY flag

This flag is set/reset in exfat_put_super()/exfat_sync_fs()
to avoid sync_blockdev().
- exfat_put_super():
Before calling this, the VFS has already called sync_filesystem(),
so sync is never performed here.
- exfat_sync_fs():
After calling this, the VFS calls sync_blockdev(), so, it is meaningless
to check EXFAT_SB_DIRTY or to bypass sync_blockdev() here.

Remove the EXFAT_SB_DIRTY check to ensure synchronization.
And remove the code related to the flag.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: fix wrong hint_stat initialization in exfat_find_dir_entry()

We found the wrong hint_stat initialization in exfat_find_dir_entry().
It should be initialized when cluster is EXFAT_EOF_CLUSTER.

Fixes: ca06197382bd ("exfat: add directory operations")
Cc: stable@vger.kernel.org # v5.7
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: flush dirty metadata in fsync

generic_file_fsync() exfat used could not guarantee the consistency of
a file because it has flushed not dirty metadata but only dirty data pages
for a file.

Instead of that, use exfat_file_fsync() for files and directories so that
it guarantees to commit both the metadata and data pages for a file.

Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: Set the unused characters of FileName field to the value 0000h

Some fsck tool complain that padding part of the FileName field
is not set to the value 0000h. So let's maintain filesystem cleaner,
as exfat's spec. recommendation.

Signed-off-by: Hyeongseok.Kim <Hyeongseok@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: standardize checksum calculation

To clarify that it is a 16-bit checksum, the parts related to the 16-bit
checksum are renamed and change type to u16.
Furthermore, replace checksum calculation in exfat_load_upcase_table()
with exfat_calc_checksum32().

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: optimize dir-cache

Optimize directory access based on exfat_entry_set_cache.
- Hold bh instead of copied d-entry.
- Modify bh->data directly instead of the copied d-entry.
- Write back the retained bh instead of rescanning the d-entry-set.
And
- Remove unused cache related definitions.

Signed-off-by: Tetsuhiro Kohada <kohada.tetsuhiro@dc.mitsubishielectric.co.jp>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: replace 'time_ms' with 'time_cs'

Replace time_ms with time_cs in the file directory entry structure
and related functions.

The unit of create_time_ms/modify_time_ms in File Directory Entry are not
'milli-second', but 'centi-second'.
The exfat specification uses the term '10ms', but instead use 'cs' as in
msdos_fs.h.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: Use a more common logging style

Remove the direct use of KERN_<LEVEL> in functions by creating
separate exfat_<level> macros.

Miscellanea:

o Remove several unnecessary terminating newlines in formats
o Realign arguments and fit to 80 columns where appropriate

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: add directory operations

This adds the implementation of directory operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>