linux-stable.git/fs/f2fs/data.c, branch v6.18

f2fs: fix wrong block mapping for multi-devices

2025-10-13T23:55:44+00:00

Assuming the disk layout as below,

disk0: 0            --- 0x00035abfff
disk1: 0x00035ac000 --- 0x00037abfff
disk2: 0x00037ac000 --- 0x00037ebfff

and we want to read data from offset=13568 having len=128 across the block
devices, we can illustrate the block addresses like below.

0 .. 0x00037ac000 ------------------- 0x00037ebfff, 0x00037ec000 -------
          |          ^            ^                                ^
          |   fofs   0            13568                            13568+128
          |       ------------------------------------------------------
          |   LBA    0x37e8aa9    0x37ebfa9                        0x37ec029
          --- map    0x3caa9      0x3ffa9

In this example, we should give the relative map of the target block device
ranging from 0x3caa9 to 0x3ffa9 where the length should be calculated by
0x37ebfff + 1 - 0x37ebfa9.

In the below equation, however, map->m_pblk was supposed to be the original
address instead of the one from the target block address.

 - map->m_len = min(map->m_len, dev->end_blk + 1 - map->m_pblk);

Cc: stable@vger.kernel.org
Fixes: 71f2c8206202 ("f2fs: multidevice: support direct IO")
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: fix UAF issue in f2fs_merge_page_bio()

2025-09-28T20:07:53+00:00

As JY reported in bugzilla [1],

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
pc : [0xffffffe51d249484] f2fs_is_cp_guaranteed+0x70/0x98
lr : [0xffffffe51d24adbc] f2fs_merge_page_bio+0x520/0x6d4
CPU: 3 UID: 0 PID: 6790 Comm: kworker/u16:3 Tainted: P    B   W  OE      6.12.30-android16-5-maybe-dirty-4k #1 5f7701c9cbf727d1eebe77c89bbbeb3371e895e5
Tainted: [P]=PROPRIETARY_MODULE, [B]=BAD_PAGE, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Workqueue: writeback wb_workfn (flush-254:49)
Call trace:
 f2fs_is_cp_guaranteed+0x70/0x98
 f2fs_inplace_write_data+0x174/0x2f4
 f2fs_do_write_data_page+0x214/0x81c
 f2fs_write_single_data_page+0x28c/0x764
 f2fs_write_data_pages+0x78c/0xce4
 do_writepages+0xe8/0x2fc
 __writeback_single_inode+0x4c/0x4b4
 writeback_sb_inodes+0x314/0x540
 __writeback_inodes_wb+0xa4/0xf4
 wb_writeback+0x160/0x448
 wb_workfn+0x2f0/0x5dc
 process_scheduled_works+0x1c8/0x458
 worker_thread+0x334/0x3f0
 kthread+0x118/0x1ac
 ret_from_fork+0x10/0x20

[1] https://bugzilla.kernel.org/show_bug.cgi?id=220575

The panic was caused by UAF issue w/ below race condition:

kworker
- writepages
 - f2fs_write_cache_pages
  - f2fs_write_single_data_page
   - f2fs_do_write_data_page
    - f2fs_inplace_write_data
     - f2fs_merge_page_bio
      - add_inu_page
      : cache page #1 into bio & cache bio in
        io->bio_list
  - f2fs_write_single_data_page
   - f2fs_do_write_data_page
    - f2fs_inplace_write_data
     - f2fs_merge_page_bio
      - add_inu_page
      : cache page #2 into bio which is linked
        in io->bio_list
						write
						- f2fs_write_begin
						: write page #1
						 - f2fs_folio_wait_writeback
						  - f2fs_submit_merged_ipu_write
						   - f2fs_submit_write_bio
						   : submit bio which inclues page #1 and #2

						software IRQ
						- f2fs_write_end_io
						 - fscrypt_free_bounce_page
						 : freed bounced page which belongs to page #2
      - inc_page_count( , WB_DATA_TYPE(data_folio), false)
      : data_folio points to fio->encrypted_page
        the bounced page can be freed before
        accessing it in f2fs_is_cp_guarantee()

It can reproduce w/ below testcase:
Run below script in shell #1:
for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \
-c "pwrite 0 32k" -c "fdatasync"

Run below script in shell #2:
for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \
-c "pwrite 0 32k" -c "fdatasync"

So, in f2fs_merge_page_bio(), let's avoid using fio->encrypted_page after
commit page into internal ipu cache.

Fixes: 0b20fcec8651 ("f2fs: cache global IPU bio")
Reported-by: JY 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: readahead node blocks in F2FS_GET_BLOCK_PRECACHE mode

2025-09-28T20:04:41+00:00

In f2fs_precache_extents(), For large files, It requires reading many
node blocks. Instead of reading each node block with synchronous I/O,
this patch applies readahead so that node blocks can be fetched in
advance.

It reduces the overhead of repeated sync reads and improves efficiency
when precaching extents of large files.

I created a file with the same largest extent and executed the test.
For this experiment, I set the file's largest extent with an offset of 0
and a size of 1GB. I configured the remaining area with 100MB extents.

5GB test file:
dd if=/dev/urandom of=test1 bs=1m count=5120
cp test1 test2
fsync test1
dd if=test1 of=test2 bs=1m skip=1024 seek=1024 count=100 conv=notrunc
dd if=test1 of=test2 bs=1m skip=1224 seek=1224 count=100 conv=notrunc
...
dd if=test1 of=test2 bs=1m skip=5024 seek=5024 count=100 conv=notrunc
reboot

I also created 10GB and 20GB files with large extents using the same
method.

ioctl(F2FS_IOC_PRECACHE_EXTENTS) test results are as follows:
  +-----------+---------+---------+-----------+
  | File size | Before  | After   | Reduction |
  +-----------+---------+---------+-----------+
  | 5GB       | 101.8ms | 37.0ms  | 72.1%     |
  | 10GB      | 222.9ms | 56.0ms  | 74.9%     |
  | 20GB      | 446.2ms | 116.4ms | 73.9%     |
  +-----------+---------+---------+-----------+
Tested on a 256GB mobile device with an SM8750 chipset.

Reviewed-by: Sungjong Seo 
Reviewed-by: Sunmin Jeong 
Signed-off-by: Yunji Kang 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: fix zero-sized extent for precache extents

2025-09-17T16:00:10+00:00

Script to reproduce:
f2fs_io write 1 0 1881 rand dsync testfile
f2fs_io fallocate 0 7708672 4096 testfile
f2fs_io write 1 1881 1 rand buffered testfile
fsync testfile
umount
mount
f2fs_io precache_extents testfile

When the data layout is something like this:
dnode1:                     dnode2:
[0]      A                  [0]    NEW_ADDR
[1]      A+1                [1]    0x0
...
[1016]   A+1016
[1017]   B (B!=A+1017)      [1017] 0x0

During precache_extents, we map the last block(valid blkaddr) in dnode1:
map->m_flags |= F2FS_MAP_MAPPED;
map->m_pblk = blkaddr(valid blkaddr);
map->m_len = 1;
then we goto next_dnode, meet the first block in dnode2(hole), goto sync_out:
map->m_flags & F2FS_MAP_MAPPED == true, and we make zero-sized extent:

map->m_len = 1
ofs = start_pgofs - map->m_lblk = 1882 - 1881 = 1
ei.fofs = start_pgofs = 1882
ei.len = map->m_len - ofs = 1 - 1 = 0

Rebased on patch[1], this patch can cover these cases to avoid zero-sized extent:
A,B,C is valid blkaddr
case1:
dnode1:                     dnode2:
[0]      A                  [0]    NEW_ADDR
[1]      A+1                [1]    0x0
...                         ....
[1016]   A+1016
[1017]   B (B!=A+1017)      [1017] 0x0

case2:
dnode1:                     dnode2:
[0]      A                  [0]    C (C!=B+1)
[1]      A+1                [1]    C+1
...                         ....
[1016]   A+1016
[1017]   B (B!=A+1017)      [1017] 0x0

case3:
dnode1:                     dnode2:
[0]      A                  [0]    C (C!=B+2)
[1]      A+1                [1]    C+1
...                         ....
[1015]   A+1015
[1016]   B (B!=A+1016)
[1017]   B+1                [1017] 0x0

[1] https://lore.kernel.org/linux-f2fs-devel/20250912081250.44383-1-chao@kernel.org/

Fixes: c4020b2da4c9 ("f2fs: support F2FS_IOC_PRECACHE_EXTENTS")
Signed-off-by: wangzijie 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: fix to update map->m_next_extent correctly in f2fs_map_blocks()

2025-09-16T02:10:54+00:00

Script to reproduce:
mkfs.f2fs -O extra_attr,compression /dev/vdb -f
mount /dev/vdb /mnt/f2fs -o mode=lfs,noextent_cache
cd /mnt/f2fs
f2fs_io write 1 0 1024 rand dsync testfile
xfs_io testfile -c "fsync"
f2fs_io write 1 0 512 rand dsync testfile
xfs_io testfile -c "fsync"
cd /
umount /mnt/f2fs
mount /dev/vdb /mnt/f2fs
f2fs_io precache_extents /mnt/f2fs/testfile
umount /mnt/f2fs

Tracepoint output:
f2fs_update_read_extent_tree_range: dev = (253,16), ino = 4, pgofs = 0, len = 512, blkaddr = 1055744, c_len = 0
f2fs_update_read_extent_tree_range: dev = (253,16), ino = 4, pgofs = 513, len = 351, blkaddr = 17921, c_len = 0
f2fs_update_read_extent_tree_range: dev = (253,16), ino = 4, pgofs = 864, len = 160, blkaddr = 18272, c_len = 0

During precache_extents, there is off-by-one issue, we should update
map->m_next_extent to pgofs rather than pgofs + 1, if last blkaddr is
valid and not contiguous to previous extent.

Fixes: c4020b2da4c9 ("f2fs: support F2FS_IOC_PRECACHE_EXTENTS")
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: clean up error handing of f2fs_submit_page_read()

2025-09-09T03:26:41+00:00

Below two functions should never fail, clean up error handling in their
callers:
1) f2fs_grab_read_bio() in f2fs_submit_page_read()
2) bio_add_folio() in f2fs_submit_page_read()

Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: merge FUA command with the existing writes

2025-09-09T03:26:36+00:00

FUA writes can be merged to the existing write IOs.

Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

Merge tag 'f2fs-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

2025-08-04T23:27:21+00:00

Pull f2fs updates from Jaegeuk Kim:
 "Three main updates: folio conversion by Matthew, switch to a new mount
  API by Hongbo and Eric, and several sysfs entries to tune GCs for ZUFS
  with finer granularity by Daeho.

  There are also patches to address bugs and issues in the existing
  features such as GCs, file pinning, write-while-dio-read, contingous
  block allocation, and memory access violations.

  Enhancements:
   - switch to new mount API and folio conversion
   - add sysfs nodes to controle F2FS GCs for ZUFS
   - improve performance on the nat entry cache
   - drop inode from the donation list when the last file is closed
   - avoid splitting bio when reading multiple pages

  Bug fixes:
   - fix to trigger foreground gc during f2fs_map_blocks() in lfs mode
   - make sure zoned device GC to use FG_GC in shortage of free section
   - fix to calculate dirty data during has_not_enough_free_secs()
   - fix to update upper_p in __get_secs_required() correctly
   - wait for inflight dio completion, excluding pinned files read using dio
   - don't break allocation when crossing contiguous sections
   - vm_unmap_ram() may be called from an invalid context
   - fix to avoid out-of-boundary access in dnode page
   - fix to avoid panic in f2fs_evict_inode
   - fix to avoid UAF in f2fs_sync_inode_meta()
   - fix to use f2fs_is_valid_blkaddr_raw() in do_write_page()
   - fix UAF of f2fs_inode_info in f2fs_free_dic
   - fix to avoid invalid wait context issue
   - fix bio memleak when committing super block
   - handle nat.blkaddr corruption in f2fs_get_node_info()

  In addition, there are also clean-ups and minor bug fixes"

* tag 'f2fs-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (109 commits)
  f2fs: drop inode from the donation list when the last file is closed
  f2fs: add gc_boost_gc_greedy sysfs node
  f2fs: add gc_boost_gc_multiple sysfs node
  f2fs: fix to trigger foreground gc during f2fs_map_blocks() in lfs mode
  f2fs: fix to calculate dirty data during has_not_enough_free_secs()
  f2fs: fix to update upper_p in __get_secs_required() correctly
  f2fs: directly add newly allocated pre-dirty nat entry to dirty set list
  f2fs: avoid redundant clean nat entry move in lru list
  f2fs: zone: wait for inflight dio completion, excluding pinned files read using dio
  f2fs: ignore valid ratio when free section count is low
  f2fs: don't break allocation when crossing contiguous sections
  f2fs: remove unnecessary tracepoint enabled check
  f2fs: merge the two conditions to avoid code duplication
  f2fs: vm_unmap_ram() may be called from an invalid context
  f2fs: fix to avoid out-of-boundary access in dnode page
  f2fs: switch to the new mount api
  f2fs: introduce fs_context_operation structure
  f2fs: separate the options parsing and options checking
  f2fs: Add f2fs_fs_context to record the mount options
  f2fs: Allow sbi to be NULL in f2fs_printk
  ...

f2fs: fix to trigger foreground gc during f2fs_map_blocks() in lfs mode

2025-07-28T16:36:54+00:00

w/ "mode=lfs" mount option, generic/299 will cause system panic as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.c:2835!
Call Trace:
 
 f2fs_allocate_data_block+0x6f4/0xc50
 f2fs_map_blocks+0x970/0x1550
 f2fs_iomap_begin+0xb2/0x1e0
 iomap_iter+0x1d6/0x430
 __iomap_dio_rw+0x208/0x9a0
 f2fs_file_write_iter+0x6b3/0xfa0
 aio_write+0x15d/0x2e0
 io_submit_one+0x55e/0xab0
 __x64_sys_io_submit+0xa5/0x230
 do_syscall_64+0x84/0x2f0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0010:new_curseg+0x70f/0x720

The root cause of we run out-of-space is: in f2fs_map_blocks(), f2fs may
trigger foreground gc only if it allocates any physical block, it will be
a little bit later when there is multiple threads writing data w/
aio/dio/bufio method in parallel, since we always use OPU in lfs mode, so
f2fs_map_blocks() does block allocations aggressively.

In order to fix this issue, let's give a chance to trigger foreground
gc in prior to block allocation in f2fs_map_blocks().

Fixes: 36abef4e796d ("f2fs: introduce mode=lfs mount option")
Cc: Daeho Jeong 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: don't break allocation when crossing contiguous sections

2025-07-24T20:18:59+00:00

Commit 0638a3197c19 ("f2fs: avoid unused block when dio write in LFS
mode") has fixed unused block issue for dio write in lfs mode.

However, f2fs_map_blocks() may break and return smaller extent when
last allocated block locates in the end of section, even allocator
can allocate contiguous blocks across sections.

Actually, for the case that allocator returns a block address which is
not contiguous w/ current extent, we can record the block address in
iomap->private, in the next round, skip reallocating for the last
allocated block, then we can fix unused block issue, meanwhile, also,
we can allocates contiguous physical blocks as much as possible for dio
write in lfs mode.

Testcase:
- mkfs.f2fs -f /dev/vdb
- mount -o mode=lfs /dev/vdb /mnt/f2fs
- dd if=/dev/zero of=/mnt/f2fs/file bs=1M count=3; sync;
- dd if=/dev/zero of=/mnt/f2fs/dio bs=2M count=1 oflag=direct;
- umount /mnt/f2fs

Before:
f2fs_map_blocks: dev = (253,16), ino = 4, file offset = 0, start blkaddr = 0x0, len = 0x100, flags = 1, seg_type = 8, may_create = 1, multidevice = 0, flag = 5, err = 0
f2fs_map_blocks: dev = (253,16), ino = 4, file offset = 256, start blkaddr = 0x0, len = 0x100, flags = 1, seg_type = 8, may_create = 1, multidevice = 0, flag = 5, err = 0
f2fs_map_blocks: dev = (253,16), ino = 4, file offset = 512, start blkaddr = 0x0, len = 0x100, flags = 1, seg_type = 8, may_create = 1, multidevice = 0, flag = 5, err = 0
f2fs_map_blocks: dev = (253,16), ino = 5, file offset = 0, start blkaddr = 0x4700, len = 0x100, flags = 3, seg_type = 1, may_create = 1, multidevice = 0, flag = 3, err = 0
f2fs_map_blocks: dev = (253,16), ino = 5, file offset = 256, start blkaddr = 0x4800, len = 0x100, flags = 3, seg_type = 1, may_create = 1, multidevice = 0, flag = 3, err = 0

After:
f2fs_map_blocks: dev = (253,16), ino = 4, file offset = 0, start blkaddr = 0x0, len = 0x100, flags = 1, seg_type = 8, may_create = 1, multidevice = 0, flag = 5, err = 0
f2fs_map_blocks: dev = (253,16), ino = 4, file offset = 256, start blkaddr = 0x0, len = 0x100, flags = 1, seg_type = 8, may_create = 1, multidevice = 0, flag = 5, err = 0
f2fs_map_blocks: dev = (253,16), ino = 4, file offset = 512, start blkaddr = 0x0, len = 0x100, flags = 1, seg_type = 8, may_create = 1, multidevice = 0, flag = 5, err = 0
f2fs_map_blocks: dev = (253,16), ino = 5, file offset = 0, start blkaddr = 0x4700, len = 0x200, flags = 3, seg_type = 1, may_create = 1, multidevice = 0, flag = 3, err = 0

Cc: Daejun Park 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim