Commit 298b1e41 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: fix to truncate preallocated blocks in f2fs_file_open() 



chenyuwen reports a f2fs bug as below:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000011
 fscrypt_set_bio_crypt_ctx+0x78/0x1e8
 f2fs_grab_read_bio+0x78/0x208
 f2fs_submit_page_read+0x44/0x154
 f2fs_get_read_data_page+0x288/0x5f4
 f2fs_get_lock_data_page+0x60/0x190
 truncate_partial_data_page+0x108/0x4fc
 f2fs_do_truncate_blocks+0x344/0x5f0
 f2fs_truncate_blocks+0x6c/0x134
 f2fs_truncate+0xd8/0x200
 f2fs_iget+0x20c/0x5ac
 do_garbage_collect+0x5d0/0xf6c
 f2fs_gc+0x22c/0x6a4
 f2fs_disable_checkpoint+0xc8/0x310
 f2fs_fill_super+0x14bc/0x1764
 mount_bdev+0x1b4/0x21c
 f2fs_mount+0x20/0x30
 legacy_get_tree+0x50/0xbc
 vfs_get_tree+0x5c/0x1b0
 do_new_mount+0x298/0x4cc
 path_mount+0x33c/0x5fc
 __arm64_sys_mount+0xcc/0x15c
 invoke_syscall+0x60/0x150
 el0_svc_common+0xb8/0xf8
 do_el0_svc+0x28/0xa0
 el0_svc+0x24/0x84
 el0t_64_sync_handler+0x88/0xec

It is because inode.i_crypt_info is not initialized during below path:
- mount
 - f2fs_fill_super
  - f2fs_disable_checkpoint
   - f2fs_gc
    - f2fs_iget
     - f2fs_truncate

So, let's relocate truncation of preallocated blocks to f2fs_file_open(),
after fscrypt_file_open().

Fixes: d4dd19ec ("f2fs: do not expose unwritten blocks to user by DIO")
Reported-by: default avatarchenyuwen <yuwen.chen@xjmz.com>
Closes: https://lore.kernel.org/linux-kernel/20240517085327.1188515-1-yuwen.chen@xjmz.com


Signed-off-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent d7409b05

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -803,6 +803,7 @@ enum { 
	FI_COW_FILE,		/* indicate COW file */

	FI_ATOMIC_COMMITTED,	/* indicate atomic commit completed except disk sync */

	FI_ATOMIC_REPLACE,	/* indicate atomic replace */

	FI_OPENED_FILE,		/* indicate file has been opened */

	FI_MAX,			/* max flag, never be used */

};

fs/f2fs/file.c

+41 −1
Original line number Diff line number Diff line
@@ -554,6 +554,42 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma) 
	return 0;

}



static int finish_preallocate_blocks(struct inode *inode)

{

	int ret;



	inode_lock(inode);

	if (is_inode_flag_set(inode, FI_OPENED_FILE)) {

		inode_unlock(inode);

		return 0;

	}



	if (!file_should_truncate(inode)) {

		set_inode_flag(inode, FI_OPENED_FILE);

		inode_unlock(inode);

		return 0;

	}



	f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	filemap_invalidate_lock(inode->i_mapping);



	truncate_setsize(inode, i_size_read(inode));

	ret = f2fs_truncate(inode);



	filemap_invalidate_unlock(inode->i_mapping);

	f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	if (!ret)

		set_inode_flag(inode, FI_OPENED_FILE);



	inode_unlock(inode);

	if (ret)

		return ret;



	file_dont_truncate(inode);

	return 0;

}



static int f2fs_file_open(struct inode *inode, struct file *filp)

{

	int err = fscrypt_file_open(inode, filp);
@@ -571,7 +607,11 @@ static int f2fs_file_open(struct inode *inode, struct file *filp) 
	filp->f_mode |= FMODE_NOWAIT;

	filp->f_mode |= FMODE_CAN_ODIRECT;



	return dquot_file_open(inode, filp);

	err = dquot_file_open(inode, filp);

	if (err)

		return err;



	return finish_preallocate_blocks(inode);

}



void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count)

fs/f2fs/inode.c

+0 −8
Original line number Diff line number Diff line
@@ -613,14 +613,6 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) 
	}

	f2fs_set_inode_flags(inode);



	if (file_should_truncate(inode) &&

			!is_sbi_flag_set(sbi, SBI_POR_DOING)) {

		ret = f2fs_truncate(inode);

		if (ret)

			goto bad_inode;

		file_dont_truncate(inode);

	}



	unlock_new_inode(inode);

	trace_f2fs_iget(inode);

	return inode;