linux-stable.git/fs/f2fs/segment.c, branch linux-6.1.y

f2fs: fix to do sanity check on dcc->discard_cmd_cnt conditionally

2026-06-19T11:37:18+00:00

[ Upstream commit 6af249c996f7d73a3435f9e577956fa259347d18 ]

Syzbot reported a f2fs bug as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.c:1900!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6527 Comm: syz.5.110 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:f2fs_issue_discard_timeout+0x59b/0x5a0 fs/f2fs/segment.c:1900
Code: d9 80 e1 07 80 c1 03 38 c1 0f 8c d6 fe ff ff 48 89 df e8 a8 5e fa fd e9 c9 fe ff ff e8 4e 46 94 fd 90 0f 0b e8 46 46 94 fd 90 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc9000494f940 EFLAGS: 00010283
RAX: ffffffff843009ca RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc9001ca78000 RSI: 00000000000029f3 RDI: 00000000000029f4
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100893a431 R12: 1ffff1100893a430
R13: 1ffff1100c2b702c R14: dffffc0000000000 R15: ffff8880449d2160
FS:  00007ffa35fed6c0(0000) GS:ffff88812643d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2b68634000 CR3: 0000000039f62000 CR4: 00000000003526f0
Call Trace:
 
 __f2fs_remount fs/f2fs/super.c:2960 [inline]
 f2fs_reconfigure+0x108a/0x1710 fs/f2fs/super.c:5443
 reconfigure_super+0x227/0x8a0 fs/super.c:1080
 do_remount fs/namespace.c:3391 [inline]
 path_mount+0xdc5/0x10e0 fs/namespace.c:4151
 do_mount fs/namespace.c:4172 [inline]
 __do_sys_mount fs/namespace.c:4361 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4338
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffa37dbda0a

The root cause is there will be race condition in between f2fs_ioc_fitrim()
and f2fs_remount():

- f2fs_remount			- f2fs_ioc_fitrim
 - f2fs_issue_discard_timeout
  - __issue_discard_cmd
  - __drop_discard_cmd
  - __wait_all_discard_cmd
				 - f2fs_trim_fs
				  - f2fs_write_checkpoint
				   - f2fs_clear_prefree_segments
				    - f2fs_issue_discard
				     - __issue_discard_async
				      - __queue_discard_cmd
				       - __update_discard_tree_range
				        - __insert_discard_cmd
				         - __create_discard_cmd
				         : atomic_inc(&dcc->discard_cmd_cnt);
  - sanity check on dcc->discard_cmd_cnt (expect discard_cmd_cnt to be zero)

This will only happen when fitrim races w/ remount rw, if we remount to
readonly filesystem, remount will wait until mnt_pcp.mnt_writers to zero,
that means fitrim is not in process at that time.

Cc: stable@kernel.org
Fixes: 2482c4325dfe ("f2fs: detect bug_on in f2fs_wait_discard_bios")
Reported-by: syzbot+62538b67389ee582837a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/69b07d7c.050a0220.8df7.09a1.GAE@google.com
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
[ adapted `f2fs_remount` call to pass `*flags & SB_RDONLY` for the old mount API ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

f2fs: use kfree() instead of kvfree() to free some memory

2026-06-19T11:37:18+00:00

[ Upstream commit e9705c61b1dbe7bac9dc189de434994d8a76b191 ]

options in f2fs_fill_super is alloc by kstrdup:
	options = kstrdup((const char *)data, GFP_KERNEL)
sit_bitmap[_mir], nat_bitmap[_mir] are alloc by kmemdup:
	sit_i->sit_bitmap = kmemdup(src_bitmap, sit_bitmap_size, GFP_KERNEL);
	sit_i->sit_bitmap_mir = kmemdup(src_bitmap,
					sit_bitmap_size, GFP_KERNEL);
	nm_i->nat_bitmap = kmemdup(version_bitmap, nm_i->bitmap_size,
					GFP_KERNEL);
	nm_i->nat_bitmap_mir = kmemdup(version_bitmap, nm_i->bitmap_size,
					GFP_KERNEL);
write_io is alloc by f2fs_kmalloc:
	sbi->write_io[i] = f2fs_kmalloc(sbi,
			array_size(n, sizeof(struct f2fs_bio_info))

Use kfree is more efficient.

Signed-off-by: Jiazi Li 
Signed-off-by: peixuan.qiu 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Stable-dep-of: 6af249c996f7 ("f2fs: fix to do sanity check on dcc->discard_cmd_cnt conditionally")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

f2fs: check curseg->inited before write_sum_page in change_curseg

2024-12-14T18:53:45+00:00

[ Upstream commit 43563069e1c1df417d2eed6eca8a22fc6b04691d ]

In the __f2fs_init_atgc_curseg->get_atssr_segment calling,
curseg->segno is NULL_SEGNO, indicating that there is no summary
block that needs to be written.

Fixes: 093749e296e2 ("f2fs: support age threshold based garbage collection")
Signed-off-by: Yongpeng Yang 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: remove the unused flush argument to change_curseg

2024-12-14T18:53:45+00:00

[ Upstream commit 5bcd655fffaec24e849bda1207446f5cc821713e ]

Signed-off-by: Christoph Hellwig 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Stable-dep-of: 43563069e1c1 ("f2fs: check curseg->inited before write_sum_page in change_curseg")
Signed-off-by: Sasha Levin

f2fs: open code allocate_segment_by_default

2024-12-14T18:53:45+00:00

[ Upstream commit 8442d94b8ac8d5d8300725a9ffa9def526b71170 ]

allocate_segment_by_default has just two callers, which use very
different code pathes inside it based on the force paramter.  Just
open code the logic in the two callers using a new helper to decided
if a new segment should be allocated.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Stable-dep-of: 43563069e1c1 ("f2fs: check curseg->inited before write_sum_page in change_curseg")
Signed-off-by: Sasha Levin

f2fs: remove struct segment_allocation default_salloc_ops

2024-12-14T18:53:45+00:00

[ Upstream commit 1c8a8ec0a0e9a1176022a35c4daf04fe1594d270 ]

There is only  single instance of these ops, so remove the indirection
and call allocate_segment_by_default directly.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Stable-dep-of: 43563069e1c1 ("f2fs: check curseg->inited before write_sum_page in change_curseg")
Signed-off-by: Sasha Levin

f2fs: fix the wrong f2fs_bug_on condition in f2fs_do_replace_block

2024-12-14T18:53:45+00:00

[ Upstream commit c3af1f13476ec23fd99c98d060a89be28c1e8871 ]

This f2fs_bug_on was introduced by commit 2c1905042c8c ("f2fs: check
segment type in __f2fs_replace_block") when there were only 6 curseg types.
After commit d0b9e42ab615 ("f2fs: introduce inmem curseg") was introduced,
the condition should be changed to checking curseg->seg_type.

Fixes: d0b9e42ab615 ("f2fs: introduce inmem curseg")
Signed-off-by: LongPing Wei 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: fix to do sanity check in update_sit_entry

2024-08-29T15:30:38+00:00

[ Upstream commit 36959d18c3cf09b3c12157c6950e18652067de77 ]

If GET_SEGNO return NULL_SEGNO for some unecpected case,
update_sit_entry will access invalid memory address,
cause system crash. It is better to do sanity check about
GET_SEGNO just like update_segment_mtime & locate_dirty_segment.

Also remove some redundant judgment code.

Signed-off-by: Zhiguo Niu 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: assign CURSEG_ALL_DATA_ATGC if blkaddr is valid

2024-08-11T10:35:54+00:00

[ Upstream commit 8cb1f4080dd91c6e6b01dbea013a3f42341cb6a1 ]

mkdir /mnt/test/comp
f2fs_io setflags compression /mnt/test/comp
dd if=/dev/zero of=/mnt/test/comp/testfile bs=16k count=1
truncate --size 13 /mnt/test/comp/testfile

In the above scenario, we can get a BUG_ON.
 kernel BUG at fs/f2fs/segment.c:3589!
 Call Trace:
  do_write_page+0x78/0x390 [f2fs]
  f2fs_outplace_write_data+0x62/0xb0 [f2fs]
  f2fs_do_write_data_page+0x275/0x740 [f2fs]
  f2fs_write_single_data_page+0x1dc/0x8f0 [f2fs]
  f2fs_write_multi_pages+0x1e5/0xae0 [f2fs]
  f2fs_write_cache_pages+0xab1/0xc60 [f2fs]
  f2fs_write_data_pages+0x2d8/0x330 [f2fs]
  do_writepages+0xcf/0x270
  __writeback_single_inode+0x44/0x350
  writeback_sb_inodes+0x242/0x530
  __writeback_inodes_wb+0x54/0xf0
  wb_writeback+0x192/0x310
  wb_workfn+0x30d/0x400

The reason is we gave CURSEG_ALL_DATA_ATGC to COMPR_ADDR where the
page was set the gcing flag by set_cluster_dirty().

Cc: stable@vger.kernel.org
Fixes: 4961acdd65c9 ("f2fs: fix to tag gcing flag on page during block migration")
Reviewed-by: Chao Yu 
Tested-by: Will McVicker 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: fix to avoid use SSR allocate when do defragment

2024-08-11T10:35:54+00:00

[ Upstream commit 21327a042dd94bc73181d7300e688699cb1f467e ]

SSR allocate mode will be used when doing file defragment
if ATGC is working at the same time, that is because
set_page_private_gcing may make CURSEG_ALL_DATA_ATGC segment
type got in f2fs_allocate_data_block when defragment page
is writeback, which may cause file fragmentation is worse.

A file with 2 fragmentations is changed as following after defragment:

----------------file info-------------------
sensorsdata :
--------------------------------------------
dev       [254:48]
ino       [0x    3029 : 12329]
mode      [0x    81b0 : 33200]
nlink     [0x       1 : 1]
uid       [0x    27e6 : 10214]
gid       [0x    27e6 : 10214]
size      [0x  242000 : 2367488]
blksize   [0x    1000 : 4096]
blocks    [0x    1210 : 4624]
--------------------------------------------

file_pos   start_blk     end_blk        blks
       0    11361121    11361207          87
  356352    11361215    11361216           2
  364544    11361218    11361218           1
  368640    11361220    11361221           2
  376832    11361224    11361225           2
  385024    11361227    11361238          12
  434176    11361240    11361252          13
  487424    11361254    11361254           1
  491520    11361271    11361279           9
  528384     3681794     3681795           2
  536576     3681797     3681797           1
  540672     3681799     3681799           1
  544768     3681803     3681803           1
  548864     3681805     3681805           1
  552960     3681807     3681807           1
  557056     3681809     3681809           1

Signed-off-by: Zhiguo Niu 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Stable-dep-of: 8cb1f4080dd9 ("f2fs: assign CURSEG_ALL_DATA_ATGC if blkaddr is valid")
Signed-off-by: Sasha Levin