AZL-66602

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

f2fs: compress: fix UAF of f2fsinodeinfo in f2fsfreedic

The decompressioctx may be released asynchronously after I/O completion. If this file is deleted immediately after read, and the kworker of processing postreadwq has not been executed yet due to high workloads, It is possible that the inode(f2fsinodeinfo) is evicted and freed before it is used f2fsfreedic.

The UAF case as below:
Thread A                                      Thread B
- f2fs_decompress_end_io
 - f2fs_put_dic
  - queue_work
    add free_dic work to post_read_wq
                                               - do_unlink
                                                - iput
                                                 - evict
                                                  - call_rcu
This file is deleted after read.

Thread C                                 kworker to process post_read_wq
- rcu_do_batch
 - f2fs_free_inode
  - kmem_cache_free
 inode is freed by rcu
                                         - process_scheduled_works
                                          - f2fs_late_free_dic
                                           - f2fs_free_dic
                                            - f2fs_release_decomp_mem
                                  read (dic->inode)->i_compress_algorithm

This patch store compress_algorithm and sbi in dic to avoid inode UAF.

In addition, the previous solution is deprecated in [1] may cause system hang. [1] https://lore.kernel.org/all/c36ab955-c8db-4a8b-a9d0-f07b5f426c3f@kernel.org