linux.git/fs/f2fs/segment.h, branch v6.16 Linux kernel source tree f2fs: add ckpt_valid_blocks to the section entry 2025-05-28T15:58:49+00:00 yohan.joung yohan.joung@sk.com 2025-05-12T07:36:10+00:00 deecd282bc39bc9b64e50a0f628a8080da27359a when performing buffered writes in a large section, overhead is incurred due to the iteration through ckpt_valid_blocks within the section. when SEGS_PER_SEC is 128, this overhead accounts for 20% within the f2fs_write_single_data_page routine. as the size of the section increases, the overhead also grows. to handle this problem ckpt_valid_blocks is added within the section entries. Test insmod null_blk.ko nr_devices=1 completion_nsec=1 submit_queues=8 hw_queue_depth=64 max_sectors=512 bs=4096 memory_backed=1 make_f2fs /dev/block/nullb0 make_f2fs -s 128 /dev/block/nullb0 fio --bs=512k --size=1536M --rw=write --name=1 --filename=/mnt/test_dir/seq_write --ioengine=io_uring --iodepth=64 --end_fsync=1 before SEGS_PER_SEC 1 2556MiB/s SEGS_PER_SEC 128 2145MiB/s after SEGS_PER_SEC 1 2556MiB/s SEGS_PER_SEC 128 2556MiB/s Signed-off-by: yohan.joung <yohan.joung@sk.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
when performing buffered writes in a large section,
overhead is incurred due to the iteration through
ckpt_valid_blocks within the section.
when SEGS_PER_SEC is 128, this overhead accounts for 20% within
the f2fs_write_single_data_page routine.
as the size of the section increases, the overhead also grows.
to handle this problem ckpt_valid_blocks is
added within the section entries.

Test
insmod null_blk.ko nr_devices=1 completion_nsec=1  submit_queues=8
hw_queue_depth=64 max_sectors=512 bs=4096 memory_backed=1
make_f2fs /dev/block/nullb0
make_f2fs -s 128 /dev/block/nullb0
fio --bs=512k --size=1536M --rw=write --name=1
--filename=/mnt/test_dir/seq_write
--ioengine=io_uring --iodepth=64 --end_fsync=1

before
SEGS_PER_SEC 1
2556MiB/s
SEGS_PER_SEC 128
2145MiB/s

after
SEGS_PER_SEC 1
2556MiB/s
SEGS_PER_SEC 128
2556MiB/s

Signed-off-by: yohan.joung <yohan.joung@sk.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: add a method for calculating the remaining blocks in the current segment in LFS mode. 2025-05-28T15:58:30+00:00 yohan.joung yohan.joung@sk.com 2025-05-12T07:36:09+00:00 249ad438e1d98b30b1ad9283bb4c4a37c4858294 In LFS mode, the previous segment cannot use invalid blocks, so the remaining blocks from the next_blkoff of the current segment to the end of the section are calculated. Signed-off-by: yohan.joung <yohan.joung@sk.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
In LFS mode, the previous segment cannot use invalid blocks,
so the remaining blocks from the next_blkoff of the current segment
to the end of the section are calculated.

Signed-off-by: yohan.joung <yohan.joung@sk.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: Convert get_next_sit_page() to get_next_sit_folio() 2025-04-28T15:26:29+00:00 Matthew Wilcox (Oracle) willy@infradead.org 2025-03-31T20:10:42+00:00 9c6b0f120e114a2294ba36b460d493152dc7655c Grab a folio instead of a page. Also convert seg_info_to_sit_page() to seg_info_to_sit_folio() and use a folio in f2fs_flush_sit_entries(). Saves a couple of calls to compound_head(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
Grab a folio instead of a page.  Also convert seg_info_to_sit_page() to
seg_info_to_sit_folio() and use a folio in f2fs_flush_sit_entries().
Saves a couple of calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: prevent the current section from being selected as a victim during GC 2025-04-12T17:05:41+00:00 yohan.joung yohan.joung@sk.com 2025-04-03T23:21:06+00:00 d26fecb03e1f1069480d41fa2a6cea87ebbb89b8 When selecting a victim using next_victim_seg in a large section, the selected section might already have been cleared and designated as the new current section, making it actively in use. This behavior causes inconsistency between the SIT and SSA. F2FS-fs (dm-54): Inconsistent segment (70961) type [0, 1] in SSA and SIT Call trace: dump_backtrace+0xe8/0x10c show_stack+0x18/0x28 dump_stack_lvl+0x50/0x6c dump_stack+0x18/0x28 f2fs_stop_checkpoint+0x1c/0x3c do_garbage_collect+0x41c/0x271c f2fs_gc+0x27c/0x828 gc_thread_func+0x290/0x88c kthread+0x11c/0x164 ret_from_fork+0x10/0x20 issue scenario segs_per_sec=2 - seg#0 and seg#1 are all dirty - all valid blocks are removed in seg#1 - gc select this sec and next_victim_seg=seg#0 - migrate seg#0, next_victim_seg=seg#1 - checkpoint -> sec(seg#0, seg#1) becomes free - allocator assigns sec(seg#0, seg#1) to curseg - gc tries to migrate seg#1 Fixes: e3080b0120a1 ("f2fs: support subsectional garbage collection") Signed-off-by: yohan.joung <yohan.joung@sk.com> Signed-off-by: Chao Yu <chao@kernel.org> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
When selecting a victim using next_victim_seg in a large section, the
selected section might already have been cleared and designated as the
new current section, making it actively in use.
This behavior causes inconsistency between the SIT and SSA.

F2FS-fs (dm-54): Inconsistent segment (70961) type [0, 1] in SSA and SIT
Call trace:
dump_backtrace+0xe8/0x10c
show_stack+0x18/0x28
dump_stack_lvl+0x50/0x6c
dump_stack+0x18/0x28
f2fs_stop_checkpoint+0x1c/0x3c
do_garbage_collect+0x41c/0x271c
f2fs_gc+0x27c/0x828
gc_thread_func+0x290/0x88c
kthread+0x11c/0x164
ret_from_fork+0x10/0x20

issue scenario
segs_per_sec=2
- seg#0 and seg#1 are all dirty
- all valid blocks are removed in seg#1
- gc select this sec and next_victim_seg=seg#0
- migrate seg#0, next_victim_seg=seg#1
- checkpoint -> sec(seg#0, seg#1)  becomes free
- allocator assigns sec(seg#0, seg#1) to curseg
- gc tries to migrate seg#1

Fixes: e3080b0120a1 ("f2fs: support subsectional garbage collection")
Signed-off-by: yohan.joung <yohan.joung@sk.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: clean up unnecessary indentation 2025-04-10T03:59:58+00:00 Jaegeuk Kim jaegeuk@kernel.org 2025-04-04T19:03:03+00:00 05d3273ad03fa5ea1177b4f3dfeeb6de4899b504 No functional change. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
No functional change.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: fix to avoid accessing uninitialized curseg 2025-03-11T03:25:53+00:00 Chao Yu chao@kernel.org 2025-02-24T10:29:23+00:00 986c50f6bca109c6cf362b4e2babcb85aba958f6 syzbot reports a f2fs bug as below: F2FS-fs (loop3): Stopped filesystem due to reason: 7 kworker/u8:7: attempt to access beyond end of device BUG: unable to handle page fault for address: ffffed1604ea3dfa RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline] RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline] RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline] RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline] RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649 <TASK> f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline] f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156 wb_do_writeback fs/fs-writeback.c:2303 [inline] wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Commit 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") allows to trigger no free segment fault in allocator, then it will update curseg->segno to NULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed to check the flag, and access invalid curseg->segno directly in below call path, then resulting in panic: - f2fs_write_inode - f2fs_is_checkpoint_ready - has_enough_free_secs - has_not_enough_free_secs - __get_secs_required - has_curseg_enough_space - get_ckpt_valid_blocks : access invalid curseg->segno To avoid this issue, let's: - check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in f2fs_write_inode(). - in has_curseg_enough_space(), save curseg->segno into a temp variable, and verify its validation before use. Fixes: 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") Reported-by: syzbot+b6b347b7a4ea1b2e29b6@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67973c2b.050a0220.11b1bb.0089.GAE@google.com Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
syzbot reports a f2fs bug as below:

F2FS-fs (loop3): Stopped filesystem due to reason: 7
kworker/u8:7: attempt to access beyond end of device
BUG: unable to handle page fault for address: ffffed1604ea3dfa
RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline]
RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline]
RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline]
RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline]
RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649
 <TASK>
 f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline]
 f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791
 write_inode fs/fs-writeback.c:1525 [inline]
 __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745
 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976
 wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156
 wb_do_writeback fs/fs-writeback.c:2303 [inline]
 wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Commit 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") allows to trigger
no free segment fault in allocator, then it will update curseg->segno to
NULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed
to check the flag, and access invalid curseg->segno directly in below call
path, then resulting in panic:

- f2fs_write_inode
 - f2fs_is_checkpoint_ready
  - has_enough_free_secs
   - has_not_enough_free_secs
    - __get_secs_required
     - has_curseg_enough_space
      - get_ckpt_valid_blocks
      : access invalid curseg->segno

To avoid this issue, let's:
- check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in
f2fs_write_inode().
- in has_curseg_enough_space(), save curseg->segno into a temp variable,
and verify its validation before use.

Fixes: 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT")
Reported-by: syzbot+b6b347b7a4ea1b2e29b6@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67973c2b.050a0220.11b1bb.0089.GAE@google.com
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: clean up the unused variable additional_reserved_segments 2024-11-01T01:24:41+00:00 LongPing Wei weilongping@oppo.com 2024-10-29T10:49:07+00:00 1df2bc3c8252261860787a02f61797a914b99163 additional_reserved_segments was introduced by commit 300a842937fb ("f2fs: fix to reserve space for IO align feature"), and its initialization was deleted by commit 87161a2b0aed ("f2fs: deprecate io_bits"). Signed-off-by: LongPing Wei <weilongping@oppo.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
additional_reserved_segments was introduced by
commit 300a842937fb ("f2fs: fix to reserve space for IO align feature"),
and its initialization was deleted by
commit 87161a2b0aed ("f2fs: deprecate io_bits").

Signed-off-by: LongPing Wei <weilongping@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: fix to parse temperature correctly in f2fs_get_segment_temp() 2024-11-01T01:24:41+00:00 Chao Yu chao@kernel.org 2024-10-22T02:01:49+00:00 9395fb09e897dcd96f601715e63018fc5c69cf03 In __get_segment_type(), __get_segment_type_6() may return CURSEG_COLD_DATA_PINNED or CURSEG_ALL_DATA_ATGC log type, but following f2fs_get_segment_temp() can only handle persistent log type, fix it. Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
In __get_segment_type(), __get_segment_type_6() may return
CURSEG_COLD_DATA_PINNED or CURSEG_ALL_DATA_ATGC log type, but
following f2fs_get_segment_temp() can only handle persistent
log type, fix it.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: modify f2fs_is_checkpoint_ready logic to allow more data to be written with the CP disable 2024-11-01T01:24:40+00:00 Qi Han hanqi@vivo.com 2024-10-25T09:18:23+00:00 84b5bb8bf0f6a78c232a20c2eecdbb8112ac2703 When the free segment is used up during CP disable, many write or ioctl operations will get ENOSPC error codes, even if there are still many blocks available. We can reproduce it in the following steps: dd if=/dev/zero of=f2fs.img bs=1M count=65 mkfs.f2fs -f f2fs.img mount f2fs.img f2fs_dir -o checkpoint=disable:10% cd f2fs_dir i=1 ; while [[ $i -lt 50 ]] ; do (file_name=./2M_file$i ; dd \ if=/dev/random of=$file_name bs=1M count=2); i=$((i+1)); done sync i=1 ; while [[ $i -lt 50 ]] ; do (file_name=./2M_file$i ; truncate \ -s 1K $file_name); i=$((i+1)); done sync dd if=/dev/zero of=./file bs=1M count=20 In f2fs_need_SSR() function, it is allowed to use SSR to allocate blocks when CP is disabled, so in f2fs_is_checkpoint_ready function, can we judge the number of invalid blocks when free segment is not enough, and return ENOSPC only if the number of invalid blocks is also not enough. Signed-off-by: Qi Han <hanqi@vivo.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
When the free segment is used up during CP disable, many write or
ioctl operations will get ENOSPC error codes, even if there are
still many blocks available. We can reproduce it in the following
steps:

dd if=/dev/zero of=f2fs.img bs=1M count=65
mkfs.f2fs -f f2fs.img
mount f2fs.img f2fs_dir -o checkpoint=disable:10%
cd f2fs_dir
i=1 ; while [[ $i -lt 50 ]] ; do (file_name=./2M_file$i ; dd \
if=/dev/random of=$file_name bs=1M count=2); i=$((i+1)); done
sync
i=1 ; while [[ $i -lt 50 ]] ; do (file_name=./2M_file$i ; truncate \
-s 1K $file_name); i=$((i+1)); done
sync
dd if=/dev/zero of=./file bs=1M count=20

In f2fs_need_SSR() function, it is allowed to use SSR to allocate
blocks when CP is disabled, so in f2fs_is_checkpoint_ready function,
can we judge the number of invalid blocks when free segment is not
enough, and return ENOSPC only if the number of invalid blocks is
also not enough.

Signed-off-by: Qi Han <hanqi@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs: zone: introduce first_zoned_segno in f2fs_sb_info 2024-11-01T01:19:00+00:00 Chao Yu chao@kernel.org 2024-10-18T06:26:36+00:00 5bc5aae843128aefb1c55d769d057c92dd8a32c9 first_zoned_segno() returns a fixed value, let's cache it in structure f2fs_sb_info to avoid redundant calculation. Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> 
first_zoned_segno() returns a fixed value, let's cache it in
structure f2fs_sb_info to avoid redundant calculation.

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