f2fs: fix return value of f2fs_recover_fsync_data()

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix return value of f2fs_recover_fsync_data()

With below scripts, it will trigger panic in f2fs:

mkfs.f2fs -f /dev/vdd

mount /dev/vdd /mnt/f2fs

touch /mnt/f2fs/foo

sync

echo 111 >> /mnt/f2fs/foo

f2fs_io fsync /mnt/f2fs/foo

f2fs_io shutdown 2 /mnt/f2fs

umount /mnt/f2fs

mount -o ro,norecovery /dev/vdd /mnt/f2fs

or

mount -o ro,disable_roll_forward /dev/vdd /mnt/f2fs

F2FS-fs (vdd): f2fs_recover_fsync_data: recovery fsync data, check_only: 0

F2FS-fs (vdd): Mounted with checkpoint version = 7f5c361f

F2FS-fs (vdd): Stopped filesystem due to reason: 0

F2FS-fs (vdd): f2fs_recover_fsync_data: recovery fsync data, check_only: 1

Filesystem f2fs get_tree() didn't set fc->root, returned 1

------------[ cut here ]------------

kernel BUG at fs/super.c:1761!

Oops: invalid opcode: 0000 [#1] SMP PTI

CPU: 3 UID: 0 PID: 722 Comm: mount Not tainted 6.18.0-rc2+ #721 PREEMPT(voluntary)

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014

RIP: 0010:vfs_get_tree.cold+0x18/0x1a

Call Trace:

<TASK>

fc_mount+0x13/0xa0

path_mount+0x34e/0xc50

__x64_sys_mount+0x121/0x150

do_syscall_64+0x84/0x800

entry_SYSCALL_64_after_hwframe+0x76/0x7e

RIP: 0033:0x7fa6cc126cfe

The root cause is we missed to handle error number returned from

f2fs_recover_fsync_data() when mounting image w/ ro,norecovery or

ro,disable_roll_forward mount option, result in returning a positive

error number to vfs_get_tree(), fix it.