f2fs: fix to avoid panic in dec_valid_node_count()
As Jungyeon reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=203213
- Overview
When mounting the attached crafted image and running program, I got this error.
Additionally, it hangs on sync after running the this script.
The image is intentionally fuzzed from a normal f2fs image for testing and I enabled option CONFIG_F2FS_CHECK_FS on.
- Reproduces
mkdir test
mount -t f2fs tmp.img test
cp a.out test
cd test
sudo ./a.out
sync
kernel BUG at fs/f2fs/f2fs.h:2012!
RIP: 0010:truncate_node+0x2c9/0x2e0
Call Trace:
f2fs_truncate_xattr_node+0xa1/0x130
f2fs_remove_inode_page+0x82/0x2d0
f2fs_evict_inode+0x2a3/0x3a0
evict+0xba/0x180
__dentry_kill+0xbe/0x160
dentry_kill+0x46/0x180
dput+0xbb/0x100
do_renameat2+0x3c9/0x550
__x64_sys_rename+0x17/0x20
do_syscall_64+0x43/0xf0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The reason is dec_valid_node_count() will trigger kernel panic due to
inconsistent count in between inode.i_blocks and actual block.
To avoid panic, let's just print debug message and set SBI_NEED_FSCK to
give a hint to fsck for latter repairing.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix build warning and add unlikely]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e08c3bc..5b06aa8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2028,7 +2028,6 @@
f2fs_bug_on(sbi, !sbi->total_valid_block_count);
f2fs_bug_on(sbi, !sbi->total_valid_node_count);
- f2fs_bug_on(sbi, !is_inode && !inode->i_blocks);
sbi->total_valid_node_count--;
sbi->total_valid_block_count--;
@@ -2038,10 +2037,19 @@
spin_unlock(&sbi->stat_lock);
- if (is_inode)
+ if (is_inode) {
dquot_free_inode(inode);
- else
+ } else {
+ if (unlikely(inode->i_blocks == 0)) {
+ f2fs_msg(sbi->sb, KERN_WARNING,
+ "Inconsistent i_blocks, ino:%lu, iblocks:%llu",
+ inode->i_ino,
+ (unsigned long long)inode->i_blocks);
+ set_sbi_flag(sbi, SBI_NEED_FSCK);
+ return;
+ }
f2fs_i_blocks_write(inode, 1, false, true);
+ }
}
static inline unsigned int valid_node_count(struct f2fs_sb_info *sbi)