ocfs2: uncache inode which has failed entering the group

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

ocfs2: uncache inode which has failed entering the group

Syzbot has reported the following BUG:

kernel BUG at fs/ocfs2/uptodate.c:509!

...

Call Trace:

<TASK>

? __die_body+0x5f/0xb0

? die+0x9e/0xc0

? do_trap+0x15a/0x3a0

? ocfs2_set_new_buffer_uptodate+0x145/0x160

? do_error_trap+0x1dc/0x2c0

? ocfs2_set_new_buffer_uptodate+0x145/0x160

? __pfx_do_error_trap+0x10/0x10

? handle_invalid_op+0x34/0x40

? ocfs2_set_new_buffer_uptodate+0x145/0x160

? exc_invalid_op+0x38/0x50

? asm_exc_invalid_op+0x1a/0x20

? ocfs2_set_new_buffer_uptodate+0x2e/0x160

? ocfs2_set_new_buffer_uptodate+0x144/0x160

? ocfs2_set_new_buffer_uptodate+0x145/0x160

ocfs2_group_add+0x39f/0x15a0

? __pfx_ocfs2_group_add+0x10/0x10

? __pfx_lock_acquire+0x10/0x10

? mnt_get_write_access+0x68/0x2b0

? __pfx_lock_release+0x10/0x10

? rcu_read_lock_any_held+0xb7/0x160

? __pfx_rcu_read_lock_any_held+0x10/0x10

? smack_log+0x123/0x540

? mnt_get_write_access+0x68/0x2b0

? mnt_get_write_access+0x68/0x2b0

? mnt_get_write_access+0x226/0x2b0

ocfs2_ioctl+0x65e/0x7d0

? __pfx_ocfs2_ioctl+0x10/0x10

? smack_file_ioctl+0x29e/0x3a0

? __pfx_smack_file_ioctl+0x10/0x10

? lockdep_hardirqs_on_prepare+0x43d/0x780

? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10

? __pfx_ocfs2_ioctl+0x10/0x10

__se_sys_ioctl+0xfb/0x170

do_syscall_64+0xf3/0x230

entry_SYSCALL_64_after_hwframe+0x77/0x7f

...

</TASK>

When 'ioctl(OCFS2_IOC_GROUP_ADD, ...)' has failed for the particular

inode in 'ocfs2_verify_group_and_input()', corresponding buffer head

remains cached and subsequent call to the same 'ioctl()' for the same

inode issues the BUG() in 'ocfs2_set_new_buffer_uptodate()' (trying

to cache the same buffer head of that inode). Fix this by uncaching

the buffer head with 'ocfs2_remove_from_cache()' on error path in

'ocfs2_group_add()'.