kernel/git/stable/linux.git/fs/f2fs/sysfs.c, branch master

f2fs: support resizable tail section and unify pinned allocation

2026-08-27T04:47:36+00:00

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//pinned_area_max_secno` as a read-only sysfs node. Signed-off-by: Daeho Jeong Signed-off-by: Sunmin Jeong Reviewed-by: Wenjie Qi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: protect critical_task_priority updates with s_umount

2026-08-05T01:30:45+00:00

The sysfs store path already takes s_umount for GC thread control entries, and ckpt_thread_ioprio is covered as well. critical_task_priority also updates checkpoint or GC kthread scheduling state, but it is not covered by that serialization. It can race with remount or teardown paths that are stopping those threads. Protect critical_task_priority sysfs writes with s_umount too. Fixes: 52190933c37a ("f2fs: sysfs: introduce critical_task_priority") Cc: stable@kernel.org Signed-off-by: Wenjie Qi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: avoid NULL checkpoint thread access in sysfs

2026-08-05T01:30:45+00:00

checkpoint_merge can be enabled even when no checkpoint merge thread is running. A read-only mount is one case: f2fs does not start f2fs_issue_ckpt there, but ckpt_thread_ioprio is still writable through sysfs. The ckpt_thread_ioprio store path updates the saved ioprio value and, when checkpoint_merge is enabled, calls set_task_ioprio() for the checkpoint thread. If cprc->f2fs_issue_ckpt is NULL, that dereferences a NULL task pointer. Protect ckpt_thread_ioprio sysfs writes with s_umount as well, so the checkpoint thread cannot disappear under the store path while updating its ioprio. Fixes: e65920661708 ("f2fs: add ckpt_thread_ioprio sysfs node") Cc: stable@kernel.org Signed-off-by: Wenjie Qi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: Run f2fs_write_end_io() asynchronously

2026-08-04T00:18:37+00:00

The bio_for_each_segment_all() loop can take more than 10 ms for a large bio on an ARM little core. This is too much for interrupt context. Hence perform the write bio completion work asynchronously if a bio is large and if f2fs_write_end_io() is called from atomic context. This patch reduces the time spent in f2fs_write_end_io() from about 10 ms to about 150 microseconds on an Arm Cortex-A520 core if the max_atc_write_bio_size parameter is changed to 16384. Signed-off-by: Bart Van Assche Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: embed f2fs_gc_kthread in f2fs_sb_info

2026-07-28T00:45:49+00:00

Instead of allocating f2fs_gc_kthread dynamically, embed it in f2fs_sb_info. This simplifies lifetime management and prepares for fixing race conditions during teardown. - __sbi_store - remount|shutdown - f2fs_stop_gc_thread - access sbi->gc_thread - sbi->gc_thread = NULL - access sbi->gc_thread->f2fs_gc_task Fixes: 52190933c37a ("f2fs: sysfs: introduce critical_task_priority") Fixes: 7950e9ac638e ("f2fs: stop gc/discard thread after fs shutdown") Cc: stable@kernel.org Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: support to report fserror

2026-05-22T03:49:06+00:00

This patch supports to report fserror, it provides another way to let userspace to monitor filesystem level error. In addition, it exports /sys/fs/f2fs/features/fserror once f2fs kernel module start to support the new feature, then generic/791 of fstests can notice the feature, and verify validation of fserror report. Cc: Darrick J. Wong Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix uninitialized kobject put in f2fs_init_sysfs()

2026-04-13T22:53:17+00:00

In f2fs_init_sysfs(), all failure paths after kset_register() jump to put_kobject, which unconditionally releases both f2fs_tune and f2fs_feat. If kobject_init_and_add(&f2fs_feat, ...) fails, f2fs_tune has not been initialized yet, so calling kobject_put(&f2fs_tune) is invalid. Fix this by splitting the unwind path so each error path only releases objects that were successfully initialized. Fixes: a907f3a68ee26ba4 ("f2fs: add a sysfs entry to reclaim POSIX_FADV_NOREUSE pages") Cc: stable@vger.kernel.org Signed-off-by: Guangshuo Li Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: protect extension_list reading with sb_lock in f2fs_sbi_show()

2026-04-13T22:53:00+00:00

In f2fs_sbi_show(), the extension_list, extension_count and hot_ext_count are read without holding sbi->sb_lock. If a concurrent sysfs store modifies the extension list via f2fs_update_extension_list(), the show path may read inconsistent count and array contents, potentially leading to out-of-bounds access or displaying stale data. Fix this by holding sb_lock around the entire extension list read and format operation. Fixes: b6a06cbbb5f7 ("f2fs: support hot file extension") Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: Add defrag_blocks sysfs node

2026-03-24T17:20:59+00:00

Add the defrag_blocks sysfs node to track the amount of data blocks moved during filesystem defragmentation. Signed-off-by: Sheng Yong Signed-off-by: liujinbao1 Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: sysfs: introduce critical_task_priority

2026-02-10T20:53:21+00:00

This patch introduces /sys/fs/f2fs//critical_task_priority, w/ this new sysfs interface, we can tune priority of f2fs_ckpt thread and f2fs_gc thread. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim