From: Daeho Jeong <daehoje...@google.com>
Fixed null inode reference when doing foreground GC for data segments of
COW inodes.
Below is a finding by Ye Bin <yebi...@huawei.com>.
There is issue as follows when test f2fs atomic write:
F2FS-fs (loop0): Can't find valid F2FS filesystem in 2th superblock
F2FS-fs (loop0): invalid crc_offset: 0
F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=1, run fsck to fix.
F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=2, run fsck to fix.
==================================================================
BUG: KASAN: null-ptr-deref in f2fs_get_dnode_of_data+0xac/0x16d0
Read of size 8 at addr 0000000000000028 by task rep/1990
CPU: 4 PID: 1990 Comm: rep Not tainted 5.19.0-rc6-next-20220715 #266
Call Trace:
<TASK>
dump_stack_lvl+0x6e/0x91
print_report.cold+0x49a/0x6bb
kasan_report+0xa8/0x130
f2fs_get_dnode_of_data+0xac/0x16d0
f2fs_do_write_data_page+0x2a5/0x1030
move_data_page+0x3c5/0xdf0
do_garbage_collect+0x2015/0x36c0
f2fs_gc+0x554/0x1d30
f2fs_balance_fs+0x7f5/0xda0
f2fs_write_single_data_page+0xb66/0xdc0
f2fs_write_cache_pages+0x716/0x1420
f2fs_write_data_pages+0x84f/0x9a0
do_writepages+0x130/0x3a0
filemap_fdatawrite_wbc+0x87/0xa0
file_write_and_wait_range+0x157/0x1c0
f2fs_do_sync_file+0x206/0x12d0
f2fs_sync_file+0x99/0xc0
vfs_fsync_range+0x75/0x140
f2fs_file_write_iter+0xd7b/0x1850
vfs_write+0x645/0x780
ksys_write+0xf1/0x1e0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
As the previous commit changed atomic write way which new a cow_inode for
atomic write file, and also mark cow_inode as FI_ATOMIC_FILE.
When f2fs_do_write_data_page write cow_inode will use cow_inode's cow_inode
which is NULL. Then will trigger null-ptr-deref.
To solve above issue, don't mark cow_inode as FI_ATOMIC_FILE.
Signed-off-by: Daeho Jeong <daehoje...@google.com>
Signed-off-by: Ye Bin <yebi...@huawei.com>
Fiexes: 3db1de0e582c("f2fs: change the current atomic write way")
---
fs/f2fs/f2fs.h | 6 ++++++
fs/f2fs/file.c | 2 +-
fs/f2fs/segment.c | 4 ++--
3 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ecd870e5d6da..3bc69bb36cb4 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -757,6 +757,7 @@ enum {
FI_ENABLE_COMPRESS, /* enable compression in "user" compression
mode */
FI_COMPRESS_RELEASED, /* compressed blocks were released */
FI_ALIGNED_WRITE, /* enable aligned write */
+ FI_COW_FILE, /* indicate copy-on-write file for atomic write
*/
FI_MAX, /* max flag, never be used */
};
@@ -3236,6 +3237,11 @@ static inline bool f2fs_is_atomic_file(struct inode
*inode)
return is_inode_flag_set(inode, FI_ATOMIC_FILE);
}
+static inline bool f2fs_is_cow_file(struct inode *inode)
+{
+ return is_inode_flag_set(inode, FI_COW_FILE);
+}
+
static inline bool f2fs_is_first_block_written(struct inode *inode)
{
return is_inode_flag_set(inode, FI_FIRST_BLOCK_WRITTEN);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 8098ed890e94..9a3571e6f564 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2061,7 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
set_inode_flag(inode, FI_ATOMIC_FILE);
- set_inode_flag(fi->cow_inode, FI_ATOMIC_FILE);
+ set_inode_flag(fi->cow_inode, FI_COW_FILE);
clear_inode_flag(fi->cow_inode, FI_INLINE_DATA);
f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 7b1d2c29aba6..f14c5a807312 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -193,7 +193,7 @@ void f2fs_abort_atomic_write(struct inode *inode, bool
clean)
if (f2fs_is_atomic_file(inode)) {
if (clean)
truncate_inode_pages_final(inode->i_mapping);
- clear_inode_flag(fi->cow_inode, FI_ATOMIC_FILE);
+ clear_inode_flag(fi->cow_inode, FI_COW_FILE);
iput(fi->cow_inode);
fi->cow_inode = NULL;
release_atomic_write_cnt(inode);
@@ -3172,7 +3172,7 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
return CURSEG_COLD_DATA;
if (file_is_hot(inode) ||
is_inode_flag_set(inode, FI_HOT_DATA) ||
- f2fs_is_atomic_file(inode))
+ f2fs_is_cow_file(inode))
return CURSEG_HOT_DATA;
return f2fs_rw_hint_to_seg_type(inode->i_write_hint);
} else {
--
2.37.1.455.g008518b4e5-goog
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