Pull f2fs updates from Jaegeuk Kim:
 "In this round, key enhancements focus on reducing inode management
  memory overhead, introducing resizable tail sections with unified
  pinned allocation, and boosting I/O throughput via parallel
  multi-device flushes and asynchronous f2fs_write_end_io() execution.
  We also add dynamic device alias reservations to allow on-the-fly
  space donation from user partitions.

  Alongside these features, critical bug fixes resolve folio race
  conditions, lingering dirty flags, dentry and block counter leaks, and
  potential deadloops in f2fs_fsync_node_pages(). Additional stability
  patches address error-path handling across symlink, sync, and
  rename/unlink operations, prevent pinned file fragmentation, and
  correct segment migration and free section accounting in
  free_segment_range.

  Enhancements:
   - reduce memory footprint of ino management
   - support dynamic reserve/release for device aliasing
   - issue multi-device flushes in parallel
   - add a way to run f2fs_write_end_io() asynchronously
   - support resizable tail section and unify pinned allocation

  Bug fixes:
   - fix to pass folio->index to f2fs_sanity_check_node_footer()
   - fix folio_nr_pages() race after put in large folio invalidate
   - fix to clear dirty flag on folio in error path
   - accurately adjust free_sections during free_segment_range
   - fix to avoid potential deadloop in f2fs_fsync_node_pages()
   - fix the error path in symlink, device alias in rename/unlink,
     f2fs_sync_fs
   - fix to migrate all curseg types during free_segment_range
   - fix to avoid pinfile fragment on fragment:{block, segment} mode
   - fix valid block count leak on data block allocation failure
   - fix dentry folio leak in find_in_level
   - reject overlapping move range after len expansion
   - fix some bugs related to file pinning, GC functions, i_size

  And, the series includes a number of minor bug fixes"

* tag 'f2fs-for-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (51 commits)
  f2fs: support resizable tail section and unify pinned allocation
  f2fs: don't leave the hashed inode while it's unlinked
  f2fs: accurately adjust free_sections during free_segment_range
  f2fs: fix to avoid potential deadloop in f2fs_fsync_node_pages()
  f2fs: use adjusted write range after f2fs_write_checks()
  f2fs: fix to propagate error from f2fs_sync_fs()
  f2fs: return symlink writeback errors
  f2fs: fix error handling on device alias check in rename and unlink
  f2fs: fix to reset all pinned status during fggc
  f2fs: use f2fs_{down, up}_(read, write}_trace() for nat_tree_lock
  f2fs: reduce memory footprint of ino management
  f2fs: fix i_size when pinned fallocate partially fails
  f2fs: fix to migrate all curseg types during free_segment_range
  f2fs: avoid setting SBI_NEED_FSCK on transient resize failure
  f2fs: fix to avoid pinfile fragment on fragment:{block, segment} mode
  f2fs: cleanup w/ f2fs_need_rand_{blk, seg, seg_blk}
  f2fs: fix to shrink gc_lock coverage in f2fs_gc_range()
  f2fs: fix to reclaim space in f2fs_allocate_pinning_section()
  f2fs: unify add/remove ino entry API for all ino types
  f2fs: fix to zero post-EOF data when extending file size
  ...

Currently, zoned block devices restrict pinned file allocations to
conventional zones at the beginning of the storage (before
first_seq_zone_segno), triggering range GC when conventional space is
exhausted.

On regular block devices, when preparing for future online filesystem
resizing (e.g. partition shrinking), pinned files must not be allocated
in the tail area that will be truncated, as pinned files cannot be
relocated by GC. Specifying the resizable tail area size (in sections)
allows uniform mount configuration across devices of different storage
capacities.

To support this, introduce a unified `pinned_area_max_secno` boundary
abstraction in `f2fs_sb_info`:
1. Add `-o resizable_tail_secno=%u` mount option to specify the number
   of sections at the tail of the filesystem reserved for resizing.
2. In `f2fs_fill_super()`, initialize `sbi->pinned_area_max_secno` as:
   min(MAIN_SECS(sbi) - resizable_tail_sec, zoned_max_sec).
3. In `get_new_segment()`, restrict segment allocation for pinned files
   (`pinning == true`) to `0 .. sbi->pinned_area_max_secno - 1`. If no
   free section is available in the pinned area, return -EAGAIN.
4. In `f2fs_allocate_pinning_section()`, unify the range GC trigger to
   run `f2fs_gc_range()` up to `sbi->pinned_area_max_secno` whenever
   `sbi->pinned_area_max_secno < MAIN_SECS(sbi)` and allocation
   returns -EAGAIN.
5. Expose `/sys/fs/f2fs/<dev>/pinned_area_max_secno` as a read-only
   sysfs node.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Sunmin Jeong <s_min.jeong@samsung.com>
Reviewed-by: Wenjie Qi <qiwenjie@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

f2fs_symlink()
1. f2fs_new_inode
2. f2fs_add_link
3. write_being|end to fill the symlink path
4. flush dirty pages and or checkpoint

Step 4 is nice to succeed, which doesn't become a reason to roll back
the created symlink. OTOH, if we get an error till step 3, don't leave
its dentry and its inode.

Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Wenjie Qi <qiwenjie@xiaomi.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by `secs`
to restrict block allocation to the safe remaining main area while valid
blocks in the truncated range are evacuated by GC.

However, FREE_I(sbi)->free_sections tracks the total number of free
sections across the whole filesystem. If any sections within the
truncated range were already free upon entering free_segment_range(),
failing to deduct them from free_sections causes the filesystem to
overestimate available free sections in the active, reduced main area.
This leads to inconsistent free section accounting during GC data
migration and can trigger unexpected allocation failures or assertion
errors when space is tight.

Fix this by calculating the number of already-free sections in the
truncated range, deducting them from free_sections upon entering
free_segment_range(), and restoring them on exit.

Fixes: b4b10061ef98 ("f2fs: refactor resize_fs to avoid meta updates in progress")
Cc: stable@vger.kernel.org
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Sunmin Jeong <s_min.jeong@samsung.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

There is potential deadloop in race condition:

Thread A				Thread B
- fsync
 - f2fs_do_sync_file
  - f2fs_fsync_node_pages
   - last_fsync_dnode
    - folio_get(last_folio)
					- f2fs_setattr
					 - f2fs_truncate
					  - f2fs_truncate_blocks
					   - f2fs_do_truncate_blocks
					    - f2fs_truncate_inode_blocks
					     - truncate_dnode
					      - truncate_node
					       - invalidate_mapping_pages
					        - folio->mapping = NULL
   - is_node_folio alwasy return false
   - atomic && !marked is always true,
     then goto retry

Cc: stable@kernel.org
Fixes: 608514deba38 ("f2fs: set fsync mark only for the last dnode")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

generic_write_checks() in f2fs_write_checks() can adjust iocb->ki_pos
for append writes and truncate the iterator to limit the number of bytes
to write.

In f2fs_file_write_iter(), the pinned-file overwrite check currently
uses the position and count saved before f2fs_write_checks(), so it
can check a range different from the actual write range.

The forced buffered I/O cleanup also uses orig_pos saved before
f2fs_write_checks(). For O_APPEND writes, this can make the cleanup
flush and invalidate the wrong page cache range.

Move the pinned-file overwrite check after f2fs_write_checks() and use
the adjusted iocb->ki_pos and iov_iter_count(from). Also save the
adjusted write position and use it for the forced buffered I/O cleanup.

Fixes: 3fdd89b452c2 ("f2fs: prevent writing without fallocate() for pinned files")
Fixes: 92318f20d703 ("f2fs: preserve direct write semantics when buffering is forced")
Signed-off-by: Seongjae Jeong <jsjlee1020@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

So that caller can detect any failure from f2fs_sync_fs().

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

F2FS writes long symlink data with page_symlink() and then flushes the
symlink mapping to reduce the chance of exposing a broken symlink.

That flush result is currently ignored. If the writeback fails, symlink()
still returns success even though the symlink is not durable and the same
operation can already surface -EIO through syncfs().

Return the writeback error to userspace and skip the dirsync flush once the
symlink data flush has failed.

Fixes: d0cae97cb600 ("f2fs: flush symlink path to avoid broken symlink after POR")
Cc: stable@kernel.org
Signed-off-by: Wenjie Qi <qiwenjie@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

In f2fs_rename() and f2fs_unlink(), directly returning -EPERM when
encountering a device aliasing file bypasses the cleanup path.

Fix this by setting err to -EPERM and jumping to the proper cleanup
labels (out_dir and out) instead of returning immediately.

Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Otherwise, the pinned status may affect latter flow of fggc.

Cc: stable@kernel.org
Fixes: 9703d69d9d15 ("f2fs: support file pinning for zoned devices")
Cc: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>