Revert "Disable cache attach and detach"

[robertbaldyga]

This reverts commit f34328a.

[Kamoppl]

I have found 3 bugs

Steps to reproduce:
(1/3, 2/3)

1. Start cache
2. Add core
3. Detach cache
4. Remove core ->
   cache1: Cannot flush core - cache device is detached
   Removing core failed. Detaching cache1.core1
   --> But core is left in inactive state
   └core 1 /dev/vdb1 Inactive - -
5. Remove inactive core ->
   [175258.094146] ------------[ cut here ]------------
   [175258.094150] kernel BUG at /root/open-cas-linux/modules/cas_cache/src/ocf/utils/utils_refcnt.c:65!
   [175258.095472] invalid opcode: 0000 [Add README and LICENSE files #1] SMP NOPTI
   [175258.096300] CPU: 7 PID: 4099689 Comm: cas_mngt_1 Tainted: G OE 5.15.0-72-generic Init SCSI request properly on newer kernels #79-Ubuntu
   [175258.097484] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.16.0-4.module_el8+603+e0ca2c01 04/01/2014
   [175258.098707] RIP: 0010:ocf_refcnt_unfreeze+0x1e/0x20 [cas_cache]
   [175258.099794] Code: 0f 0b 0f 0b 0f 0b 66 0f 1f 44 00 00 0f 1f 44 00 00 55 b8 ff ff ff ff 48 89 e5 f0 0f c1 47 04 83 e8 01 78 06 5d c3 cc cc cc cc <0f> 0b 0f 1f 44 00 00 55 8b 47 04 85 c0 48 89 e5 0f 95 c0 5d c3 cc
   [175258.102354] RSP: 0018:ff53da78489fbde0 EFLAGS: 00010297
   [175258.103332] RAX: 00000000ffffffff RBX: ff53da7848ae1078 RCX: 0000000000000027
   [175258.104470] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ff53da7848ae10a0
   [175258.105601] RBP: ff53da78489fbde0 R08: 0000000000000003 R09: fffffffffffff2f0
   [175258.106726] R10: ffffffffffffffff R11: 0000000000000001 R12: ff53da7848ae1000
   [175258.107851] R13: ff53da7848ae1000 R14: ff53da7848ae1000 R15: ff53da7848c28080
   [175258.108977] FS: 0000000000000000(0000) GS:ff1485fb9fc40000(0000) knlGS:0000000000000000
   [175258.110182] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [175258.111211] CR2: 00007f8c706f9000 CR3: 0000000891e58006 CR4: 0000000000771ee0
   [175258.112350] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [175258.113489] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   [175258.114619] PKRU: 55555554
   [175258.115408] Call Trace:
   [175258.116165]
   [175258.116901] ocf_cleaner_refcnt_unfreeze+0x25/0x60 [cas_cache]
   [175258.117928] ocf_mngt_cache_remove_core_finish+0x5d/0xc0 [cas_cache]
   [175258.118983] _ocf_pipeline_run_step+0xad/0x160 [cas_cache]
   [175258.119964] ocf_queue_run+0xf0/0x110 [cas_cache]
   [175258.120879] _cas_io_queue_thread+0x6f/0x110 [cas_cache]
   [175258.121836] ? wait_woken+0x70/0x70
   [175258.122671] ? env_sort+0x240/0x240 [cas_cache]
   [175258.123555] kthread+0x127/0x150
   [175258.124328] ? set_kthread_struct+0x50/0x50
   [175258.125168] ret_from_fork+0x1f/0x30
   [175258.125983]
   [175258.126664] Modules linked in: tls null_blk xfs drbd_transport_tcp(OE) xt_conntrack nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xfrm_user xfrm_algo nft_counter xt_addrtype nft_compat nf_tables nfnetlink br_netfilter bridge stp llc overlay binfmt_misc nls_iso8859_1 intel_rapl_msr intel_rapl_common ppdev nfit kvm_intel cas_cache(OE) joydev kvm input_leds rapl parport_pc serio_raw parport mac_hid sch_fq_codel handshake(OE) dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua drbd(OE) lru_cache ramoops reed_solomon pstore_blk pstore_zone efi_pstore ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic usbhid hid virtio_gpu virtio_dma_buf drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops crct10dif_pclmul crc32_pclmul ghash_clmulni_intel virtio_net cec rc_core ahci aesni_intel
   [175258.126880] crypto_simd net_failover i2c_i801 xhci_pci cryptd psmouse drm libahci lpc_ich i2c_smbus virtio_blk xhci_pci_renesas failover [last unloaded: null_blk]
   [175258.140397] ---[ end trace 0a1e7b356b4127a0 ]---
   [175258.141286] RIP: 0010:ocf_refcnt_unfreeze+0x1e/0x20 [cas_cache]
   [175258.142411] Code: 0f 0b 0f 0b 0f 0b 66 0f 1f 44 00 00 0f 1f 44 00 00 55 b8 ff ff ff ff 48 89 e5 f0 0f c1 47 04 83 e8 01 78 06 5d c3 cc cc cc cc <0f> 0b 0f 1f 44 00 00 55 8b 47 04 85 c0 48 89 e5 0f 95 c0 5d c3 cc
   [175258.144903] RSP: 0018:ff53da78489fbde0 EFLAGS: 00010297
   [175258.145927] RAX: 00000000ffffffff RBX: ff53da7848ae1078 RCX: 0000000000000027
   [175258.146998] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ff53da7848ae10a0
   [175258.148056] RBP: ff53da78489fbde0 R08: 0000000000000003 R09: fffffffffffff2f0
   [175258.149109] R10: ffffffffffffffff R11: 0000000000000001 R12: ff53da7848ae1000
   [175258.150298] R13: ff53da7848ae1000 R14: ff53da7848ae1000 R15: ff53da7848c28080
   [175258.151345] FS: 0000000000000000(0000) GS:ff1485fb9fc40000(0000) knlGS:0000000000000000
   [175258.152459] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [175258.153385] CR2: 00007f8c706f9000 CR3: 0000000891e58006 CR4: 0000000000771ee0
   [175258.154550] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [175258.155585] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

(3/3)

1. Start 40 MB cache
2. Detach cache
3. Attach 100 MB cache
4. Detach cache
5. Attach 40MB cache
   ->
   cache1: Couldn't fit metadata structure on device. Please try bigger cache device.
   cache1: Attaching cache device failed

It looks like bug occurs while cache attach operation using smaller disk than it was detached with