Merge tag 'f2fs-for-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "In this development cycle, we focused on several key performance
  optimizations:

   - introducing large folio support to enhance read speeds for
     immutable files

   - reducing checkpoint=enable latency by flushing only committed dirty
     pages

   - implementing tracepoints to diagnose and resolve lock priority
     inversion.

  Additionally, we introduced the packed_ssa feature to optimize the SSA
  footprint when utilizing large block sizes.

  Detail summary:

  Enhancements:
   - support large folio for immutable non-compressed case
   - support non-4KB block size without packed_ssa feature
   - optimize f2fs_enable_checkpoint() to avoid long delay
   - optimize f2fs_overwrite_io() for f2fs_iomap_begin
   - optimize NAT block loading during checkpoint write
   - add write latency stats for NAT and SIT blocks in
     f2fs_write_checkpoint
   - pin files do not require sbi->writepages lock for ordering
   - avoid f2fs_map_blocks() for consecutive holes in readpages
   - flush plug periodically during GC to maximize readahead effect
   - add tracepoints to catch lock overheads
   - add several sysfs entries to tune internal lock priorities

  Fixes:
   - fix lock priority inversion issue
   - fix incomplete block usage in compact SSA summaries
   - fix to show simulate_lock_timeout correctly
   - fix to avoid mapping wrong physical block for swapfile
   - fix IS_CHECKPOINTED flag inconsistency issue caused by
     concurrent atomic commit and checkpoint writes
   - fix to avoid UAF in f2fs_write_end_io()"

* tag 'f2fs-for-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (61 commits)
  f2fs: sysfs: introduce critical_task_priority
  f2fs: introduce trace_f2fs_priority_update
  f2fs: fix lock priority inversion issue
  f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin
  f2fs: fix incomplete block usage in compact SSA summaries
  f2fs: decrease maximum flush retry count in f2fs_enable_checkpoint()
  f2fs: optimize NAT block loading during checkpoint write
  f2fs: change size parameter of __has_cursum_space() to unsigned int
  f2fs: add write latency stats for NAT and SIT blocks in f2fs_write_checkpoint
  f2fs: pin files do not require sbi->writepages lock for ordering
  f2fs: fix to show simulate_lock_timeout correctly
  f2fs: introduce FAULT_SKIP_WRITE
  f2fs: check skipped write in f2fs_enable_checkpoint()
  Revert "f2fs: add timeout in f2fs_enable_checkpoint()"
  f2fs: fix to unlock folio in f2fs_read_data_large_folio()
  f2fs: fix error path handling in f2fs_read_data_large_folio()
  f2fs: use folio_end_read
  f2fs: fix to avoid mapping wrong physical block for swapfile
  f2fs: avoid f2fs_map_blocks() for consecutive holes in readpages
  f2fs: advance index and offset after zeroing in large folio read
  ...

Author: torvalds

Documentation/ABI/testing/sysfs-fs-f2fs

@@ -520,7 +520,7 @@ What:		/sys/fs/f2fs/<disk>/ckpt_thread_ioprio
 Date:		January 2021
 Contact:	"Daeho Jeong" <daehojeong@google.com>
 Description:	Give a way to change checkpoint merge daemon's io priority.
-		Its default value is "be,3", which means "BE" I/O class and
+		Its default value is "rt,3", which means "RT" I/O class and
 		I/O priority "3". We can select the class between "rt" and "be",
 		and set the I/O priority within valid range of it. "," delimiter
 		is necessary in between I/O class and priority number.
@@ -732,7 +732,7 @@ Description:	Support configuring fault injection type, should be
 		FAULT_TRUNCATE                   0x00000400
 		FAULT_READ_IO                    0x00000800
 		FAULT_CHECKPOINT                 0x00001000
-		FAULT_DISCARD                    0x00002000
+		FAULT_DISCARD                    0x00002000 (obsolete)
 		FAULT_WRITE_IO                   0x00004000
 		FAULT_SLAB_ALLOC                 0x00008000
 		FAULT_DQUOT_INIT                 0x00010000
@@ -741,8 +741,10 @@ Description:	Support configuring fault injection type, should be
 		FAULT_BLKADDR_CONSISTENCE        0x00080000
 		FAULT_NO_SEGMENT                 0x00100000
 		FAULT_INCONSISTENT_FOOTER        0x00200000
-		FAULT_TIMEOUT                    0x00400000 (1000ms)
+		FAULT_ATOMIC_TIMEOUT             0x00400000 (1000ms)
 		FAULT_VMALLOC                    0x00800000
+		FAULT_LOCK_TIMEOUT               0x01000000 (1000ms)
+		FAULT_SKIP_WRITE                 0x02000000
 		===========================      ==========
 
 What:		/sys/fs/f2fs/<disk>/discard_io_aware_gran
@@ -939,3 +941,57 @@ Description:	Controls write priority in multi-devices setups. A value of 0 means
 		allocate_section_policy = 1  Prioritize writing to section before allocate_section_hint
 		allocate_section_policy = 2  Prioritize writing to section after allocate_section_hint
 		===========================  ==========================================================
+
+What:		/sys/fs/f2fs/<disk>/max_lock_elapsed_time
+Date:		December 2025
+Contact:	"Chao Yu" <chao@kernel.org>
+Description:	This is a threshold, once a thread enters critical region that lock covers, total
+		elapsed time exceeds this threshold, f2fs will print tracepoint to dump information
+		of related context. This sysfs entry can be used to control the value of threshold,
+		by default, the value is 500 ms.
+
+What:		/sys/fs/f2fs/<disk>/inject_timeout_type
+Date:		December 2025
+Contact:	"Chao Yu" <chao@kernel.org>
+Description:	This sysfs entry can be used to change type of injected timeout:
+		==========     ===============================
+		Flag_Value     Flag_Description
+		==========     ===============================
+		0x00000000     No timeout (default)
+		0x00000001     Simulate running time
+		0x00000002     Simulate IO type sleep time
+		0x00000003     Simulate Non-IO type sleep time
+		0x00000004     Simulate runnable time
+		==========     ===============================
+
+What:		/sys/fs/f2fs/<disk>/adjust_lock_priority
+Date:		January 2026
+Contact:	"Chao Yu" <chao@kernel.org>
+Description:	This sysfs entry can be used to enable/disable to adjust priority for task
+		which is in critical region covered by lock.
+		==========     ==================
+		Flag_Value     Flag_Description
+		==========     ==================
+		0x00000000     Disabled (default)
+		0x00000001     cp_rwsem
+		0x00000002     node_change
+		0x00000004     node_write
+		0x00000008     gc_lock
+		0x00000010     cp_global
+		0x00000020     io_rwsem
+		==========     ==================
+
+What:		/sys/fs/f2fs/<disk>/lock_duration_priority
+Date:		January 2026
+Contact:	"Chao Yu" <chao@kernel.org>
+Description:	f2fs can tune priority of thread which has entered into critical region covered by
+		f2fs rwsemphore lock. This sysfs entry can be used to control priority value, the
+		range is [100,139], by default the value is 120.
+
+What:		/sys/fs/f2fs/<disk>/critical_task_priority
+Date:		February 2026
+Contact:	"Chao Yu" <chao@kernel.org>
+Description:	It can be used to tune priority of f2fs critical task, e.g. f2fs_ckpt, f2fs_gc
+		threads, limitation as below:
+		- it requires user has CAP_SYS_NICE capability.
+		- the range is [100, 139], by default the value is 100.

Documentation/filesystems/f2fs.rst

@@ -206,7 +206,7 @@ fault_type=%d		 Support configuring fault injection type, should be
 			     FAULT_TRUNCATE                   0x00000400
 			     FAULT_READ_IO                    0x00000800
 			     FAULT_CHECKPOINT                 0x00001000
-			     FAULT_DISCARD                    0x00002000
+			     FAULT_DISCARD                    0x00002000 (obsolete)
 			     FAULT_WRITE_IO                   0x00004000
 			     FAULT_SLAB_ALLOC                 0x00008000
 			     FAULT_DQUOT_INIT                 0x00010000
@@ -215,8 +215,10 @@ fault_type=%d		 Support configuring fault injection type, should be
 			     FAULT_BLKADDR_CONSISTENCE        0x00080000
 			     FAULT_NO_SEGMENT                 0x00100000
 			     FAULT_INCONSISTENT_FOOTER        0x00200000
-			     FAULT_TIMEOUT                    0x00400000 (1000ms)
+			     FAULT_ATOMIC_TIMEOUT             0x00400000 (1000ms)
 			     FAULT_VMALLOC                    0x00800000
+			     FAULT_LOCK_TIMEOUT               0x01000000 (1000ms)
+			     FAULT_SKIP_WRITE                 0x02000000
 			     ===========================      ==========
 mode=%s			 Control block allocation mode which supports "adaptive"
 			 and "lfs". In "lfs" mode, there should be no random
@@ -1033,3 +1035,46 @@ the reserved space back to F2FS for its own use.
 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.
+
+Per-file Read-Only Large Folio Support
+--------------------------------------
+
+F2FS implements large folio support on the read path to leverage high-order
+page allocation for significant performance gains. To minimize code complexity,
+this support is currently excluded from the write path, which requires handling
+complex optimizations such as compression and block allocation modes.
+
+This optional feature is triggered only when a file's immutable bit is set.
+Consequently, F2FS will return EOPNOTSUPP if a user attempts to open a cached
+file with write permissions, even immediately after clearing the bit. Write
+access is only restored once the cached inode is dropped. The usage flow is
+demonstrated below:
+
+.. code-block::
+
+   # f2fs_io setflags immutable /data/testfile_read_seq
+
+   /* flush and reload the inode to enable the large folio */
+   # sync && echo 3 > /proc/sys/vm/drop_caches
+
+   /* mmap(MAP_POPULATE) + mlock() */
+   # f2fs_io read 128 0 1024 mmap 1 0 /data/testfile_read_seq
+
+   /* mmap() + fadvise(POSIX_FADV_WILLNEED) + mlock() */
+   # f2fs_io read 128 0 1024 fadvise 1 0 /data/testfile_read_seq
+
+   /* mmap() + mlock2(MLOCK_ONFAULT) + madvise(MADV_POPULATE_READ) */
+   # f2fs_io read 128 0 1024 madvise 1 0 /data/testfile_read_seq
+
+   # f2fs_io clearflags immutable /data/testfile_read_seq
+
+   # f2fs_io write 1 0 1 zero buffered /data/testfile_read_seq
+   Failed to open /mnt/test/test: Operation not supported
+
+   /* flush and reload the inode to disable the large folio */
+   # sync && echo 3 > /proc/sys/vm/drop_caches
+
+   # f2fs_io write 1 0 1 zero buffered /data/testfile_read_seq
+   Written 4096 bytes with pattern = zero, total_time = 29 us, max_latency = 28 us
+
+   # rm /data/testfile_read_seq