An infinite loop may occur if the following conditions occur due to
file system corruption.

(1) Condition for exfat_count_dir_entries() to loop infinitely.
    - The cluster chain includes a loop.
    - There is no UNUSED entry in the cluster chain.

(2) Condition for exfat_create_upcase_table() to loop infinitely.
    - The cluster chain of the root directory includes a loop.
    - There are no UNUSED entry and up-case table entry in the cluster
      chain of the root directory.

(3) Condition for exfat_load_bitmap() to loop infinitely.
    - The cluster chain of the root directory includes a loop.
    - There are no UNUSED entry and bitmap entry in the cluster chain
      of the root directory.

(4) Condition for exfat_find_dir_entry() to loop infinitely.
    - The cluster chain includes a loop.
    - The unused directory entries were exhausted by some operation.

(5) Condition for exfat_check_dir_empty() to loop infinitely.
    - The cluster chain includes a loop.
    - The unused directory entries were exhausted by some operation.
    - All files and sub-directories under the directory are deleted.

This commit adds checks to break the above infinite loop.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

Test: androbench by default setting, use 64GB sdcard.
 the random write speed:
	without this patch 3.5MB/s
	with this patch 7MB/s

After patch "11a347fb6cef", the random write speed decreased significantly.
the .write_iter() interface had been modified, and check the differences
with generic_file_write_iter(), when calling generic_write_sync() and
exfat_file_write_iter() to call vfs_fsync_range(), the fdatasync flag is
wrong, and make not use the fdatasync mode, and make random write speed
decreased. So use generic_write_sync() instead of vfs_fsync_range().

Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength")
Signed-off-by: Zhengxu Zhang <zhengxu.zhang@unisoc.com>
Acked-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

Pull mmap_prepare updates from Christian Brauner:
 "Last cycle we introduce f_op->mmap_prepare() in c84bf6dd2b83 ("mm:
  introduce new .mmap_prepare() file callback").

  This is preferred to the existing f_op->mmap() hook as it does require
  a VMA to be established yet, thus allowing the mmap logic to invoke
  this hook far, far earlier, prior to inserting a VMA into the virtual
  address space, or performing any other heavy handed operations.

  This allows for much simpler unwinding on error, and for there to be a
  single attempt at merging a VMA rather than having to possibly
  reattempt a merge based on potentially altered VMA state.

  Far more importantly, it prevents inappropriate manipulation of
  incompletely initialised VMA state, which is something that has been
  the cause of bugs and complexity in the past.

  The intent is to gradually deprecate f_op->mmap, and in that vein this
  series coverts the majority of file systems to using f_op->mmap_prepare.

  Prerequisite steps are taken - firstly ensuring all checks for mmap
  capabilities use the file_has_valid_mmap_hooks() helper rather than
  directly checking for f_op->mmap (which is now not a valid check) and
  secondly updating daxdev_mapping_supported() to not require a VMA
  parameter to allow ext4 and xfs to be converted.

  Commit bb666b7c2707 ("mm: add mmap_prepare() compatibility layer for
  nested file systems") handles the nasty edge-case of nested file
  systems like overlayfs, which introduces a compatibility shim to allow
  f_op->mmap_prepare() to be invoked from an f_op->mmap() callback.

  This allows for nested filesystems to continue to function correctly
  with all file systems regardless of which callback is used. Once we
  finally convert all file systems, this shim can be removed.

  As a result, ecryptfs, fuse, and overlayfs remain unaltered so they
  can nest all other file systems.

  We additionally do not update resctl - as this requires an update to
  remap_pfn_range() (or an alternative to it) which we defer to a later
  series, equally we do not update cramfs which needs a mixed mapping
  insertion with the same issue, nor do we update procfs, hugetlbfs,
  syfs or kernfs all of which require VMAs for internal state and hooks.
  We shall return to all of these later"

* tag 'vfs-6.17-rc1.mmap_prepare' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  doc: update porting, vfs documentation to describe mmap_prepare()
  fs: replace mmap hook with .mmap_prepare for simple mappings
  fs: convert most other generic_file_*mmap() users to .mmap_prepare()
  fs: convert simple use of generic_file_*_mmap() to .mmap_prepare()
  mm/filemap: introduce generic_file_*_mmap_prepare() helpers
  fs/xfs: transition from deprecated .mmap hook to .mmap_prepare
  fs/ext4: transition from deprecated .mmap hook to .mmap_prepare
  fs/dax: make it possible to check dev dax support without a VMA
  fs: consistently use can_mmap_file() helper
  mm/nommu: use file_has_valid_mmap_hooks() helper
  mm: rename call_mmap/mmap_prepare to vfs_mmap/mmap_prepare

Pull misc VFS updates from Christian Brauner:
 "This contains the usual selections of misc updates for this cycle.

  Features:

   - Add ext4 IOCB_DONTCACHE support

     This refactors the address_space_operations write_begin() and
     write_end() callbacks to take const struct kiocb * as their first
     argument, allowing IOCB flags such as IOCB_DONTCACHE to propagate
     to the filesystem's buffered I/O path.

     Ext4 is updated to implement handling of the IOCB_DONTCACHE flag
     and advertises support via the FOP_DONTCACHE file operation flag.

     Additionally, the i915 driver's shmem write paths are updated to
     bypass the legacy write_begin/write_end interface in favor of
     directly calling write_iter() with a constructed synchronous kiocb.
     Another i915 change replaces a manual write loop with
     kernel_write() during GEM shmem object creation.

  Cleanups:

   - don't duplicate vfs_open() in kernel_file_open()

   - proc_fd_getattr(): don't bother with S_ISDIR() check

   - fs/ecryptfs: replace snprintf with sysfs_emit in show function

   - vfs: Remove unnecessary list_for_each_entry_safe() from
     evict_inodes()

   - filelock: add new locks_wake_up_waiter() helper

   - fs: Remove three arguments from block_write_end()

   - VFS: change old_dir and new_dir in struct renamedata to dentrys

   - netfs: Remove unused declaration netfs_queue_write_request()

  Fixes:

   - eventpoll: Fix semi-unbounded recursion

   - eventpoll: fix sphinx documentation build warning

   - fs/read_write: Fix spelling typo

   - fs: annotate data race between poll_schedule_timeout() and
     pollwake()

   - fs/pipe: set FMODE_NOWAIT in create_pipe_files()

   - docs/vfs: update references to i_mutex to i_rwsem

   - fs/buffer: remove comment about hard sectorsize

   - fs/buffer: remove the min and max limit checks in __getblk_slow()

   - fs/libfs: don't assume blocksize <= PAGE_SIZE in
     generic_check_addressable

   - fs_context: fix parameter name in infofc() macro

   - fs: Prevent file descriptor table allocations exceeding INT_MAX"

* tag 'vfs-6.17-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
  netfs: Remove unused declaration netfs_queue_write_request()
  eventpoll: fix sphinx documentation build warning
  ext4: support uncached buffered I/O
  mm/pagemap: add write_begin_get_folio() helper function
  fs: change write_begin/write_end interface to take struct kiocb *
  drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter
  drm/i915: Use kernel_write() in shmem object create
  eventpoll: Fix semi-unbounded recursion
  vfs: Remove unnecessary list_for_each_entry_safe() from evict_inodes()
  fs/libfs: don't assume blocksize <= PAGE_SIZE in generic_check_addressable
  fs/buffer: remove the min and max limit checks in __getblk_slow()
  fs: Prevent file descriptor table allocations exceeding INT_MAX
  fs: Remove three arguments from block_write_end()
  fs/ecryptfs: replace snprintf with sysfs_emit in show function
  fs: annotate suspected data race between poll_schedule_timeout() and pollwake()
  docs/vfs: update references to i_mutex to i_rwsem
  fs/buffer: remove comment about hard sectorsize
  fs_context: fix parameter name in infofc() macro
  VFS: change old_dir and new_dir in struct renamedata to dentrys
  proc_fd_getattr(): don't bother with S_ISDIR() check
  ...

Change the address_space_operations callbacks write_begin() and
write_end() to take struct kiocb * as the first argument instead of
struct file *.

Update all affected function prototypes, implementations, call sites,
and related documentation across VFS, filesystems, and block layer.

Part of a series refactoring address_space_operations write_begin and
write_end callbacks to use struct kiocb for passing write context and
flags.

Signed-off-by: Taotao Chen <chentaotao@didiglobal.com>
Link: https://lore.kernel.org/20250716093559.217344-4-chentaotao@didiglobal.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file
callback"), the f_op->mmap() hook has been deprecated in favour of
f_op->mmap_prepare().

This callback is invoked in the mmap() logic far earlier, so error handling
can be performed more safely without complicated and bug-prone state
unwinding required should an error arise.

This hook also avoids passing a pointer to a not-yet-correctly-established
VMA avoiding any issues with referencing this data structure.

It rather provides a pointer to the new struct vm_area_desc descriptor type
which contains all required state and allows easy setting of required
parameters without any consideration needing to be paid to locking or
reference counts.

Note that nested filesystems like overlayfs are compatible with an
.mmap_prepare() callback since commit bb666b7c2707 ("mm: add mmap_prepare()
compatibility layer for nested file systems").

In this patch we apply this change to file systems with relatively simple
mmap() hook logic - exfat, ceph, f2fs, bcachefs, zonefs, btrfs, ocfs2,
orangefs, nilfs2, romfs, ramfs and aio.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/f528ac4f35b9378931bd800920fee53fc0c5c74d.1750099179.git.lorenzo.stoakes@oracle.com
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

... to be used instead of manually assigning to ->s_d_op.
All in-tree filesystem converted (and field itself is renamed,
so any out-of-tree ones in need of conversion will be caught
by compiler).

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

xfstests generic/482 tests the file system consistency after each
FUA operation. It fails when run on exfat.

exFAT clears the volume dirty flag with a FUA operation during sync.
Since s_lock is not held when data is being written to a file, sync
can be executed at the same time. When data is being written to a
file, the FAT chain is updated first, and then the file size is
updated. If sync is executed between updating them, the length of the
FAT chain may be inconsistent with the file size.

To avoid the situation where the file system is inconsistent but the
volume dirty flag is cleared, this commit moves the clearing of the
volume dirty flag from exfat_fs_sync() to exfat_put_super(), so that
the volume dirty flag is not cleared until unmounting. After the
move, there is no additional action during sync, so exfat_fs_sync()
can be deleted.

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

The double free could happen in the following path.

exfat_create_upcase_table()
        exfat_create_upcase_table() : return error
        exfat_free_upcase_table() : free ->vol_utbl
        exfat_load_default_upcase_table : return error
     exfat_kill_sb()
           delayed_free()
                  exfat_free_upcase_table() <--------- double free
This patch set ->vol_util as NULL after freeing it.

Reported-by: Jianzhou Zhao <xnxc22xnxc22@qq.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

With commit 11a347fb6cef ("exfat: change to get file size from DataLength"),
exfat_get_block() can now handle valid_size. However, most partial
unwritten blocks that could be mapped with other blocks are being
inefficiently processed separately as individual blocks.

Except for partial unwritten blocks that require independent processing,
let's handle them simply as before.

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