linux/fs
Chao Yu 59237a2177 f2fs: optimize iteration over sparse directories
Wei Chen reports a kernel bug as blew:

INFO: task syz-executor.0:29056 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc5 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:14632 pid:29056 ppid:  6574 flags:0x00000004
Call Trace:
 __schedule+0x4a1/0x1720
 schedule+0x36/0xe0
 rwsem_down_write_slowpath+0x322/0x7a0
 fscrypt_ioctl_set_policy+0x11f/0x2a0
 __f2fs_ioctl+0x1a9f/0x5780
 f2fs_ioctl+0x89/0x3a0
 __x64_sys_ioctl+0xe8/0x140
 do_syscall_64+0x34/0xb0
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Eric did some investigation on this issue, quoted from reply of Eric:

"Well, the quality of this bug report has a lot to be desired (not on
upstream kernel, reproducer is full of totally irrelevant stuff, not
sent to the mailing list of the filesystem whose disk image is being
fuzzed, etc.).  But what is going on is that f2fs_empty_dir() doesn't
consider the case of a directory with an extremely large i_size on a
malicious disk image.

Specifically, the reproducer mounts an f2fs image with a directory
that has an i_size of 14814520042850357248, then calls
FS_IOC_SET_ENCRYPTION_POLICY on it.

That results in a call to f2fs_empty_dir() to check whether the
directory is empty.  f2fs_empty_dir() then iterates through all
3616826182336513 blocks the directory allegedly contains to check
whether any contain anything.  i_rwsem is held during this, so
anything else that tries to take it will hang."

In order to solve this issue, let's use f2fs_get_next_page_offset()
to speed up iteration by skipping holes for all below functions:
- f2fs_empty_dir
- f2fs_readdir
- find_in_level

The way why we can speed up iteration was described in
'commit 3cf4574705 ("f2fs: introduce get_next_page_offset to speed
up SEEK_DATA")'.

Meanwhile, in f2fs_empty_dir(), let's use f2fs_find_data_page()
instead f2fs_get_lock_data_page(), due to i_rwsem was held in
caller of f2fs_empty_dir(), there shouldn't be any races, so it's
fine to not lock dentry page during lookuping dirents in the page.

Link: https://lore.kernel.org/lkml/536944df-a0ae-1dd8-148f-510b476e1347@kernel.org/T/
Reported-by: Wei Chen <harperchen1110@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2022-11-11 09:48:24 -08:00
..
9p 9p: Fix some kernel-doc comments 2022-07-02 18:52:21 +09:00
adfs fs: Convert block_read_full_page() to block_read_full_folio() 2022-05-09 16:21:44 -04:00
affs affs: move from strlcpy with unused retval to strscpy 2022-08-19 13:03:10 +02:00
afs struct file-related stuff 2022-10-06 17:13:18 -07:00
autofs autofs: remove unused ino field inode 2022-07-17 17:31:42 -07:00
befs befs: Convert befs_symlink_read_folio() to use a folio 2022-08-02 12:34:03 -04:00
bfs fs: Convert block_read_full_page() to block_read_full_folio() 2022-05-09 16:21:44 -04:00
btrfs tmpfile API change 2022-10-10 19:45:17 -07:00
cachefiles cachefiles: use vfs_tmpfile_open() helper 2022-09-24 07:00:00 +02:00
ceph Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
cifs smb3: improve SMB3 change notification support 2022-10-15 10:05:53 -05:00
coda coda: Convert coda_symlink_filler() to use a folio 2022-08-02 12:34:03 -04:00
configfs
cramfs cramfs: read_mapping_page() is synchronous 2022-08-02 12:34:02 -04:00
crypto STATX_DIOALIGN for 6.1 2022-10-03 20:33:41 -07:00
debugfs debugfs: use DEFINE_SHOW_ATTRIBUTE to define debugfs_regset32_fops 2022-09-24 15:00:48 +02:00
devpts
dlm Networking changes for 6.1. 2022-10-04 13:38:03 -07:00
ecryptfs whack-a-mole: constifying struct path * 2022-10-06 17:31:02 -07:00
efivarfs efi: vars: Move efivar caching layer into efivarfs 2022-06-24 20:40:19 +02:00
efs efs: Convert efs symlinks to read_folio 2022-05-09 16:21:45 -04:00
erofs for-6.1/block-2022-10-03 2022-10-07 09:19:14 -07:00
exfat treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
exportfs Change calling conventions for filldir_t 2022-08-17 17:25:04 -04:00
ext2 treewide: use prandom_u32_max() when possible, part 2 2022-10-11 17:42:58 -06:00
ext4 Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
f2fs f2fs: optimize iteration over sparse directories 2022-11-11 09:48:24 -08:00
fat treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
freevxfs freevxfs: Convert vxfs_immed_read_folio() to use a folio 2022-08-02 12:34:03 -04:00
fscache fscache: add tracepoint when failing cookie 2022-08-09 14:13:59 +01:00
fuse tmpfile API change 2022-10-10 19:45:17 -07:00
gfs2 gfs2 debugfs improvements 2022-10-10 20:13:22 -07:00
hfs hfs: replace kmap() with kmap_local_page() in btree.c 2022-09-11 21:55:09 -07:00
hfsplus hfsplus: convert kmap() to kmap_local_page() in btree.c 2022-09-11 21:55:05 -07:00
hostfs hostfs: move from strlcpy with unused retval to strscpy 2022-09-19 22:46:25 +02:00
hpfs hpfs: Convert symlinks to read_folio 2022-05-09 16:21:45 -04:00
hugetlbfs tmpfile API change 2022-10-10 19:45:17 -07:00
iomap iomap: add a tracepoint for mappings returned by map_blocks 2022-10-02 11:42:19 -07:00
isofs - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
jbd2 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
jffs2 mtd: always initialize 'stats' in struct mtd_oob_ops 2022-09-21 10:38:07 +02:00
jfs Folio changes for 6.0 2022-08-03 10:35:43 -07:00
kernfs kernfs: fix use-after-free in __kernfs_remove 2022-09-24 13:52:27 +02:00
ksmbd 24 ksmbd server fixes 2022-10-07 08:19:26 -07:00
lockd SUNRPC: Parametrize how much of argsize should be zeroed 2022-09-26 14:02:42 -04:00
minix vfs: open inside ->tmpfile() 2022-09-24 07:00:00 +02:00
netfs netfs: do not unlock and put the folio twice 2022-07-14 10:10:12 +02:00
nfs NFS Client Updates for Linux 6.1 2022-10-13 09:58:42 -07:00
nfs_common
nfsd treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
nilfs2 Five hotfixes - three for nilfs2, two for MM. For are cc:stable, one is 2022-10-12 11:16:58 -07:00
nls
notify Merge tag 'fsnotify-for_v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2022-10-07 08:28:50 -07:00
ntfs - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
ntfs3 treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
ocfs2 - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
omfs fs: Convert block_read_full_page() to block_read_full_folio() 2022-05-09 16:21:44 -04:00
openpromfs
orangefs Orangefs: change iterate to iterate_shared 2022-10-13 09:56:14 -07:00
overlayfs tmpfile API change 2022-10-10 19:45:17 -07:00
proc - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
pstore Revert "pstore: migrate to crypto acomp interface" 2022-09-30 08:16:06 -07:00
qnx4 fs: Convert block_read_full_page() to block_read_full_folio() 2022-05-09 16:21:44 -04:00
qnx6 fs/qnx6: delete unnecessary checks before brelse() 2022-09-11 21:55:07 -07:00
quota quota: Add more checking after reading from quota file 2022-09-29 15:37:30 +02:00
ramfs tmpfile API change 2022-10-10 19:45:17 -07:00
reiserfs - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
romfs romfs: Convert romfs to read_folio 2022-05-09 16:21:46 -04:00
smbfs_common smb3: define missing create contexts 2022-10-05 01:55:27 -05:00
squashfs squashfs: don't call kmalloc in decompressors 2022-08-28 14:02:45 -07:00
sysfs kobject: kobj_type: remove default_attrs 2022-04-05 15:39:19 +02:00
sysv Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
tracefs tracefs: Only clobber mode/uid/gid on remount if asked 2022-09-08 17:10:54 -04:00
ubifs Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
udf tmpfile API change 2022-10-10 19:45:17 -07:00
ufs ufs: replace ll_rw_block() 2022-09-11 20:26:07 -07:00
unicode
vboxsf vboxsf: Convert vboxsf to read_folio 2022-05-09 16:21:46 -04:00
verity for-6.1-tag 2022-10-06 17:36:48 -07:00
xfs treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
zonefs New code for 6.0: 2022-08-11 13:11:49 -07:00
aio.c aio: use atomic_try_cmpxchg in __get_reqs_available 2022-09-11 21:55:08 -07:00
anon_inodes.c dynamic_dname(): drop unused dentry argument 2022-08-20 11:34:04 -04:00
attr.c vfs: Check the truncate maximum size in inode_newsize_ok() 2022-08-08 10:39:29 -07:00
bad_inode.c vfs: open inside ->tmpfile() 2022-09-24 07:00:00 +02:00
binfmt_elf_fdpic.c
binfmt_elf_test.c
binfmt_elf.c revert "fs/binfmt_elf: use PT_LOAD p_align values for static PIE" 2022-04-15 14:49:56 -07:00
binfmt_flat.c binfmt_flat: Remove shared library support 2022-04-22 10:57:18 -07:00
binfmt_misc.c
binfmt_script.c
buffer.c - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
char_dev.c
compat_binfmt_elf.c
coredump.c - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
d_path.c d_path.c: typo fix... 2022-08-20 11:34:33 -04:00
dax.c Merge branch 'for-6.0/dax' into libnvdimm-fixes 2022-09-24 18:14:12 -07:00
dcache.c tmpfile API change 2022-10-10 19:45:17 -07:00
direct-io.c block: remove PSI accounting from the bio layer 2022-09-20 08:24:38 -06:00
drop_caches.c
eventfd.c eventfd: guard wake_up in eventfd fs calls as well 2022-09-21 10:30:42 -06:00
eventpoll.c epoll: use try_cmpxchg in list_add_tail_lockless 2022-09-11 21:55:07 -07:00
exec.c - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
fcntl.c keep iocb_flags() result cached in struct file 2022-06-10 16:10:23 -04:00
fhandle.c do_sys_name_to_handle(): constify path 2022-09-01 17:36:39 -04:00
file_table.c locks: fix TOCTOU race when granting write lease 2022-08-16 10:59:54 -04:00
file.c gfs2: Add glockfd debugfs file 2022-06-29 13:07:16 +02:00
filesystems.c
fs_context.c
fs_parser.c
fs_pin.c
fs_struct.c
fs_types.c
fs-writeback.c fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE 2022-09-29 23:02:00 -04:00
fsopen.c uninline may_mount() and don't opencode it in fspick(2)/fsopen(2) 2022-05-19 23:25:10 -04:00
init.c
inode.c saner inode_init_always() 2022-10-06 16:49:00 -07:00
internal.h whack-a-mole: constifying struct path * 2022-10-06 17:31:02 -07:00
ioctl.c Fixes for 5.18-rc1: 2022-04-01 19:35:56 -07:00
Kconfig hugetlb: make hugetlb depends on SYSFS or SYSCTL 2022-09-11 20:26:10 -07:00
Kconfig.binfmt Xtensa updates for v6.1 2022-10-10 14:21:11 -07:00
kernel_read_file.c fs/kernel_read_file: allow to read files up-to ssize_t 2022-06-16 19:58:21 -07:00
libfs.c fs: uninline inode_maybe_inc_iversion() 2022-10-03 14:21:43 -07:00
locks.c locks: Fix dropped call to ->fl_release_private() 2022-08-17 15:08:58 -04:00
Makefile a.out: Remove the a.out implementation 2022-09-27 07:11:02 -07:00
mbcache.c mbcache: Avoid nesting of cache->c_list_lock under bit locks 2022-09-30 23:46:52 -04:00
mount.h switch try_to_unlazy_next() to __legitimize_mnt() 2022-07-05 16:18:21 -04:00
mpage.c Folio changes for 6.0 2022-08-03 10:35:43 -07:00
namei.c tmpfile API change 2022-10-10 19:45:17 -07:00
namespace.c fs: require CAP_SYS_ADMIN in target namespace for idmapped mounts 2022-08-17 11:27:11 +02:00
no-block.c
nsfs.c dynamic_dname(): drop unused dentry argument 2022-08-20 11:34:04 -04:00
open.c struct file-related stuff 2022-10-06 17:13:18 -07:00
pipe.c dynamic_dname(): drop unused dentry argument 2022-08-20 11:34:04 -04:00
pnode.c
pnode.h
posix_acl.c - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
proc_namespace.c vfs: escape hash as well 2022-06-28 13:58:05 -04:00
read_write.c [coredump] don't use __kernel_write() on kmap_local_page() 2022-09-28 14:28:40 -04:00
readdir.c Change calling conventions for filldir_t 2022-08-17 17:25:04 -04:00
remap_range.c - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
select.c
seq_file.c rxrpc: Fix locking issue 2022-05-22 21:03:01 +01:00
signalfd.c
splice.c iter_to_pipe(): switch to advancing variant of iov_iter_get_pages() 2022-08-08 22:37:23 -04:00
stack.c
stat.c vfs: support STATX_DIOALIGN on block devices 2022-09-11 19:47:12 -05:00
statfs.c
super.c fscrypt: stop using keyrings subsystem for fscrypt_master_key 2022-09-21 20:33:06 -07:00
sync.c riscv: compat: syscall: Add compat_sys_call_table implementation 2022-04-26 13:36:25 -07:00
sysctls.c
timerfd.c
userfaultfd.c - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
utimes.c
xattr.c xattr: always us is_posix_acl_xattr() helper 2022-09-21 12:01:29 +02:00