[PATCH 2/3] f2fs: move release of block devices to after kill_block_super()

[Eric Biggers]

From: Eric Biggers <ebigg...@google.com>

Call destroy_device_list() and free the f2fs_sb_info from
kill_f2fs_super(), after the call to kill_block_super().  This is
necessary to order it after the call to fscrypt_destroy_keyring() once
generic_shutdown_super() starts calling fscrypt_destroy_keyring() just
after calling ->put_super.  This is because fscrypt_destroy_keyring()
may call into f2fs_get_devices() via the fscrypt_operations.

Signed-off-by: Eric Biggers <ebigg...@google.com>
---
 fs/f2fs/super.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 033af907c3b1d..ba95a341a9a36 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1710,42 +1710,39 @@ static void f2fs_put_super(struct super_block *sb)
        f2fs_destroy_node_manager(sbi);
        f2fs_destroy_segment_manager(sbi);
 
        /* flush s_error_work before sbi destroy */
        flush_work(&sbi->s_error_work);
 
        f2fs_destroy_post_read_wq(sbi);
 
        kvfree(sbi->ckpt);
 
-       sb->s_fs_info = NULL;
        if (sbi->s_chksum_driver)
                crypto_free_shash(sbi->s_chksum_driver);
        kfree(sbi->raw_super);
 
-       destroy_device_list(sbi);
        f2fs_destroy_page_array_cache(sbi);
        f2fs_destroy_xattr_caches(sbi);
        mempool_destroy(sbi->write_io_dummy);
 #ifdef CONFIG_QUOTA
        for (i = 0; i < MAXQUOTAS; i++)
                kfree(F2FS_OPTION(sbi).s_qf_names[i]);
 #endif
        fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy);
        destroy_percpu_info(sbi);
        f2fs_destroy_iostat(sbi);
        for (i = 0; i < NR_PAGE_TYPE; i++)
                kvfree(sbi->write_io[i]);
 #if IS_ENABLED(CONFIG_UNICODE)
        utf8_unload(sb->s_encoding);
 #endif
-       kfree(sbi);
 }
 
 int f2fs_sync_fs(struct super_block *sb, int sync)
 {
        struct f2fs_sb_info *sbi = F2FS_SB(sb);
        int err = 0;
 
        if (unlikely(f2fs_cp_error(sbi)))
                return 0;
        if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
@@ -4895,23 +4892,23 @@ static int f2fs_fill_super(struct super_block *sb, void 
*data, int silent)
 }
 
 static struct dentry *f2fs_mount(struct file_system_type *fs_type, int flags,
                        const char *dev_name, void *data)
 {
        return mount_bdev(fs_type, flags, dev_name, data, f2fs_fill_super);
 }
 
 static void kill_f2fs_super(struct super_block *sb)
 {
-       if (sb->s_root) {
-               struct f2fs_sb_info *sbi = F2FS_SB(sb);
+       struct f2fs_sb_info *sbi = F2FS_SB(sb);
 
+       if (sb->s_root) {
                set_sbi_flag(sbi, SBI_IS_CLOSE);
                f2fs_stop_gc_thread(sbi);
                f2fs_stop_discard_thread(sbi);
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
                /*
                 * latter evict_inode() can bypass checking and invalidating
                 * compress inode cache.
                 */
                if (test_opt(sbi, COMPRESS_CACHE))
@@ -4924,20 +4921,25 @@ static void kill_f2fs_super(struct super_block *sb)
                                .reason = CP_UMOUNT,
                        };
                        stat_inc_cp_call_count(sbi, TOTAL_CALL);
                        f2fs_write_checkpoint(sbi, &cpc);
                }
 
                if (is_sbi_flag_set(sbi, SBI_IS_RECOVERED) && f2fs_readonly(sb))
                        sb->s_flags &= ~SB_RDONLY;
        }
        kill_block_super(sb);
+       if (sbi) {
+               destroy_device_list(sbi);
+               kfree(sbi);
+               sb->s_fs_info = NULL;
+       }
 }
 
 static struct file_system_type f2fs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "f2fs",
        .mount          = f2fs_mount,
        .kill_sb        = kill_f2fs_super,
        .fs_flags       = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
 };
 MODULE_ALIAS_FS("f2fs");
-- 
2.43.0