Merge tag 'f2fs-for-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

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
  ...

2 files changed, 60 insertions, 1 deletions

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 1b58c029abd0..0cebc89799dd 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -986,6 +986,7 @@ Description:	This sysfs entry can be used to enable/disable to adjust priority f
 		0x00000008     gc_lock
 		0x00000010     cp_global
 		0x00000020     io_rwsem
+		0x00000040     nat_tree_lock
 		==========     ==================
 
 What:		/sys/fs/f2fs/<disk>/lock_duration_priority
@@ -1002,3 +1003,20 @@ Description:	It can be used to tune priority of f2fs critical task, e.g. f2fs_ck
 		threads, limitation as below:
 		- it requires user has CAP_SYS_NICE capability.
 		- the range is [100, 139], by default the value is 120.
+
+What:		/sys/fs/f2fs/<disk>/max_atc_write_bio_size
+Date:		June 2026
+Contact:	Bart Van Assche <bvanassche@acm.org>
+Description:	Every time a write operation completes f2fs_write_end_io() is
+		called. This function may be called from an atomic context,
+		e.g. from inside an interrupt handler. This attribute controls
+		the maximum size of a write bio that is completed in atomic
+		(atc) context. The default value for this attribute is UINT_MAX
+		which means that this functionality is disabled by default.
+
+What:		/sys/fs/f2fs/<disk>/pinned_area_max_secno
+Date:		August 2026
+Contact:	"Daeho Jeong" <daehojeong@google.com>
+Description:	This is a read-only entry to show the upper bound section number
+		for pinned files. Pinned files will only be allocated within
+		sections 0 to pinned_area_max_secno - 1.
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index b45d7a687625..771216f45207 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -415,7 +415,13 @@ lookup_mode=%s		 Control the directory lookup behavior for casefolded
 			     auto               F2FS determines the mode based on the
 					        on-disk `SB_ENC_NO_COMPAT_FALLBACK_FL`
 					        flag.
-			     ================== ========================================
+resizable_tail_secno=%u  Control the number of sections at the tail of the
+			 filesystem reserved for online resizing. Pinned files
+			 will only be allocated within sections 0 to
+			 (MAIN_SECS - resizable_tail_secno) - 1. If set to 0
+			 (default), there is no tail restriction unless running
+			 on a zoned block device where conventional zones are
+			 used.
 ======================== ============================================================
 
 Debugfs Entries
@@ -1043,6 +1049,41 @@ So, the key idea is, user can do any file operations on /dev/vdc, and
 reclaim the space after the use, while the space is counted as /data.
 That doesn't require modifying partition size and filesystem format.
 
+Dynamic Device Aliasing Management
+----------------------------------
+
+In addition to static device aliasing by deleting the aliasing file, F2FS
+supports dynamic management of device aliasing. This mechanism allows the system
+to dynamically transition partition ownership between F2FS userdata and external
+entities (e.g., zRAM, raw partition) based on system requirements without
+deleting the master aliasing file or requiring unmount/remount.
+
+The master aliasing file is created during the initial format of the file system
+and remains as a persistent control entity (ioctl gateway) in the root directory.
+
+- Partition Reservation (In-service to Aliased)
+  When a specific partition needs to be dedicated to external services (e.g., zRAM),
+  a user can reserve the device alias range via ioctl. The kernel resets GC victim
+  information for the target range, marks segments as in-use to prevent new
+  allocations, and triggers forced GC to migrate existing valid data out of the
+  range. Finally, it reserves these blocks in the SIT to effectively exclude the
+  device from the usable capacity.
+
+- Partition Release (Aliased to In-service)
+  When external usage concludes, the space is reclaimed not by deleting the file,
+  but through the release ioctl. The kernel truncates blocks associated with
+  the file, releasing them back to general filesystem allocation.
+
+.. code-block::
+
+   # f2fs_io dev_alias release /mnt/f2fs/vdc.file
+   # df -h
+   /dev/vdb                            64G  753M   64G   2% /mnt/f2fs
+
+   # f2fs_io dev_alias reserve /mnt/f2fs/vdc.file
+   # df -h
+   /dev/vdb                            64G   33G   32G  52% /mnt/f2fs
+
 Per-file Read-Only Large Folio Support
 --------------------------------------