[PATCH] f2fs: fix potential panic during fstrim

From: Chao Yu
Date: Sun Oct 01 2017 - 14:50:16 EST

As Ju Hyung Park reported:

"When 'fstrim' is called for manual trim, a BUG() can be triggered
randomly with this patch.

I'm seeing this issue on both x86 Desktop and arm64 Android phone.

On x86 Desktop, this was caused during Ubuntu boot-up. I have a
cronjob installed which calls 'fstrim -v /' during boot. On arm64
Android, this was caused during GC looping with 1ms gc_min_sleep_time
& gc_max_sleep_time."

Root cause of this issue is that f2fs_wait_discard_bios can only be
used by f2fs_put_super, because during put_super there must be no
other referrers, so it can ignore discard entry's reference count
when removing the entry, otherwise in other caller we will hit bug_on
in __remove_discard_cmd as there may be other issuer added reference
count in discard entry.

Thread A Thread B
- issue_discard_thread
- f2fs_ioc_fitrim
- f2fs_trim_fs
- f2fs_wait_discard_bios
- __issue_discard_cmd
- __submit_discard_cmd
- __wait_discard_cmd
- dc->ref++
- __wait_one_discard_bio
- __wait_discard_cmd
- __remove_discard_cmd
- f2fs_bug_on(sbi, dc->ref)

Fixes: 969d1b180d987c2be02de890d0fff0f66a0e80de
Reported-by: Ju Hyung Park <qkrwngud825@xxxxxxxxx>
Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
fs/f2fs/f2fs.h | 2 +-
fs/f2fs/segment.c | 6 +++---
fs/f2fs/super.c | 2 +-
3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9a7c90386947..4b4a72f392be 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2525,7 +2525,7 @@ void invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
bool is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
void refresh_sit_entry(struct f2fs_sb_info *sbi, block_t old, block_t new);
void stop_discard_thread(struct f2fs_sb_info *sbi);
-void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
+void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi, bool umount);
void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc);
void release_discard_addrs(struct f2fs_sb_info *sbi);
int npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index dedf0209d820..e28245b7e44e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1210,11 +1210,11 @@ void stop_discard_thread(struct f2fs_sb_info *sbi)
}

/* This comes from f2fs_put_super and f2fs_trim_fs */
-void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
+void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi, bool umount)
{
__issue_discard_cmd(sbi, false);
__drop_discard_cmd(sbi);
- __wait_discard_cmd(sbi, false);
+ __wait_discard_cmd(sbi, !umount);
}

static void mark_discard_range_all(struct f2fs_sb_info *sbi)
@@ -2244,7 +2244,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
}
/* It's time to issue all the filed discards */
mark_discard_range_all(sbi);
- f2fs_wait_discard_bios(sbi);
+ f2fs_wait_discard_bios(sbi, false);
out:
range->len = F2FS_BLK_TO_BYTES(cpc.trimmed);
return err;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 89f61eb3d167..933c3d529e65 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -801,7 +801,7 @@ static void f2fs_put_super(struct super_block *sb)
}

/* be sure to wait for any on-going discard commands */
- f2fs_wait_discard_bios(sbi);
+ f2fs_wait_discard_bios(sbi, true);

if (f2fs_discard_en(sbi) && !sbi->discard_blks) {
struct cp_control cpc = {
--
2.14.1.145.gb3622a4ee

On 2017/10/2 3:29, Ju Hyung Park wrote:
> When 'fstrim' is called for manual trim, a BUG() can be triggered
> randomly with this patch.
>
> I'm seeing this issue on both x86 Desktop and arm64 Android phone.
>
> On x86 Desktop, this was caused during Ubuntu boot-up. I have a
> cronjob installed
> which calls 'fstrim -v /' during boot.
> On arm64 Android, this was caused during GC looping with
> 1ms gc_min_sleep_time & gc_max_sleep_time.
>
> Thanks.
>
> [26671.666421] ------------[ cut here ]------------
> [26671.666426] WARNING: CPU: 8 PID: 103479 at fs/f2fs/segment.c:797
> __remove_discard_cmd+0xb9/0xd0
> [26671.666427] Modules linked in: ftdi_sio usbserial uas usb_storage
> vmnet(O) vmw_vsock_vmci_transport vsock vmw_vmci vmmon(O) rfcomm
> xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4
> iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
> xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge
> stp llc bnep ebtable_filter ebtables ip6table_filter ip6_tables
> xt_multiport iptable_filter binfmt_misc snd_hda_codec_hdmi eeepc_wmi
> asus_wmi sparse_keymap video wmi_bmof mxm_wmi nls_iso8859_1 btusb
> btrtl joydev btbcm btintel input_leds bluetooth edac_mce_amd
> snd_hda_codec_realtek snd_hda_codec_generic kvm_amd kvm irqbypass
> snd_seq_dummy snd_hda_intel snd_hda_codec snd_seq_oss snd_seq_midi
> snd_hda_core snd_seq_midi_event snd_hwdep snd_pcm snd_rawmidi snd_seq
> snd_seq_device
> [26671.666450] snd_timer snd soundcore k10temp i2c_piix4
> nvidia_uvm(PO) shpchp wmi 8250_dw mac_hid parport_pc ppdev nfsd lp
> auth_rpcgss parport oid_registry nfs_acl lockd grace sunrpc ip_tables
> x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy
> async_pq async_xor async_tx raid1 multipath linear hid_generic
> hid_apple usbhid nvidia_drm(PO) nvidia_modeset(PO) nvidia(PO)
> drm_kms_helper syscopyarea sysfillrect sysimgblt igb fb_sys_fops dca
> ptp drm pps_core i2c_algo_bit ahci libahci gpio_amdpt gpio_generic
> [26671.666471] CPU: 8 PID: 103479 Comm: fstrim Tainted: P O
> 4.13.4-zen+ #1
> [26671.666472] Hardware name: System manufacturer System Product
> Name/PRIME X399-A, BIOS 0318 08/11/2017
> [26671.666472] task: ffff8804ad535800 task.stack: ffff88047ee38000
> [26671.666474] RIP: 0010:__remove_discard_cmd+0xb9/0xd0
> [26671.666474] RSP: 0018:ffff88047ee3bd00 EFLAGS: 00010202
> [26671.666475] RAX: ffff88081801a500 RBX: ffff88047eeaed00 RCX: ffff88047eeaedf8
> [26671.666475] RDX: 0000000000000001 RSI: ffff88047eeaed00 RDI: ffff880802555800
> [26671.666476] RBP: ffff8808134d0000 R08: ffff8804ad535800 R09: 0000000000000001
> [26671.666476] R10: ffff88047ee3bd18 R11: 0000000000000000 R12: ffff880802555800
> [26671.666476] R13: 0000000000000000 R14: ffff88047eeaedd0 R15: ffff8808134d0000
> [26671.666477] FS: 00007f44cddad2c0(0000) GS:ffff88081ca00000(0000)
> knlGS:0000000000000000
> [26671.666478] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [26671.666478] CR2: 00007f88f5776328 CR3: 000000058ce4a000 CR4: 00000000003406e0
> [26671.666479] Call Trace:
> [26671.666481] ? __wait_discard_cmd+0x7a/0xc0
> [26671.666482] ? f2fs_trim_fs+0x1c1/0x210
> [26671.666484] ? f2fs_ioctl+0x75a/0x2320
> [26671.666486] ? do_filp_open+0x99/0xe0
> [26671.666487] ? cp_new_stat+0x138/0x150
> [26671.666489] ? do_vfs_ioctl+0x88/0x5c0
> [26671.666490] ? SyS_newfstat+0x29/0x40
> [26671.666491] ? SyS_ioctl+0x6f/0x80
> [26671.666493] ? entry_SYSCALL_64_fastpath+0x1e/0xa9
> [26671.666493] Code: 48 89 de 8b 43 1c 48 8b 3d 4d 8c 31 01 29 85 74
> 22 00 00 e8 fa 01 d5 ff f0 ff 8d 80 22 00 00 5b 5d c3 c7 43 64 00 00
> 00 00 eb 92 <0f> ff f0 80 4f 20 04 e9 53 ff ff ff 90 66 2e 0f 1f 84 00
> 00 00
> [26671.666506] ---[ end trace 613553f7a4728b5a ]---
> [26672.553742] general protection fault: 0000 [#1] PREEMPT SMP
> [26672.553746] Modules linked in: ftdi_sio usbserial uas usb_storage
> vmnet(O) vmw_vsock_vmci_transport vsock vmw_vmci vmmon(O) rfcomm
> xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4
> iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
> xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge
> stp llc bnep ebtable_filter ebtables ip6table_filter ip6_tables
> xt_multiport iptable_filter binfmt_misc snd_hda_codec_hdmi eeepc_wmi
> asus_wmi sparse_keymap video wmi_bmof mxm_wmi nls_iso8859_1 btusb
> btrtl joydev btbcm btintel input_leds bluetooth edac_mce_amd
> snd_hda_codec_realtek snd_hda_codec_generic kvm_amd kvm irqbypass
> snd_seq_dummy snd_hda_intel snd_hda_codec snd_seq_oss snd_seq_midi
> snd_hda_core snd_seq_midi_event snd_hwdep snd_pcm snd_rawmidi snd_seq
> snd_seq_device
> [26672.553771] snd_timer snd soundcore k10temp i2c_piix4
> nvidia_uvm(PO) shpchp wmi 8250_dw mac_hid parport_pc ppdev nfsd lp
> auth_rpcgss parport oid_registry nfs_acl lockd grace sunrpc ip_tables
> x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy
> async_pq async_xor async_tx raid1 multipath linear hid_generic
> hid_apple usbhid nvidia_drm(PO) nvidia_modeset(PO) nvidia(PO)
> drm_kms_helper syscopyarea sysfillrect sysimgblt igb fb_sys_fops dca
> ptp drm pps_core i2c_algo_bit ahci libahci gpio_amdpt gpio_generic
> [26672.553792] CPU: 10 PID: 1287 Comm: f2fs_discard-25 Tainted: P
> W O 4.13.4-zen+ #1
> [26672.553793] Hardware name: System manufacturer System Product
> Name/PRIME X399-A, BIOS 0318 08/11/2017
> [26672.553794] task: ffff8808159c1600 task.stack: ffff880813304000
> [26672.553798] RIP: 0010:__remove_discard_cmd+0x6a/0xd0
> [26672.553799] RSP: 0018:ffff880813307e20 EFLAGS: 00010296
> [26672.553800] RAX: dead000000000200 RBX: ffff88047eeaed00 RCX: ffff8808159c1601
> [26672.553801] RDX: dead000000000100 RSI: ffff8808134d2288 RDI: ffff88047eeaed00
> [26672.553801] RBP: ffff8808134d0000 R08: 0000184230172c00 R09: 0000000000000006
> [26672.553802] R10: ffff880813307e38 R11: 0000000000000023 R12: ffff880802555800
> [26672.553803] R13: 0000000000000001 R14: ffff88047eeaed00 R15: ffff8808134d0000
> [26672.553804] FS: 0000000000000000(0000) GS:ffff88081ca80000(0000)
> knlGS:0000000000000000
> [26672.553805] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [26672.553805] CR2: 00007f88f2f71328 CR3: 000000048be79000 CR4: 00000000003406e0
> [26672.553806] Call Trace:
> [26672.553808] ? __wait_one_discard_bio+0x41/0x60
> [26672.553809] ? __wait_discard_cmd+0xbb/0xc0
> [26672.553811] ? issue_discard_thread+0x196/0x200
> [26672.553813] ? wait_woken+0x80/0x80
> [26672.553814] ? mark_discard_range_all.isra.11+0x40/0x40
> [26672.553816] ? kthread+0x112/0x130
> [26672.553817] ? kthread_create_on_node+0x40/0x40
> [26672.553818] ? do_group_exit+0x2e/0xa0
> [26672.553820] ? ret_from_fork+0x25/0x30
> [26672.553821] Code: 8b 43 20 48 8b 3f e8 56 6c fe ff 58 80 7b 62 02
> 75 07 f0 ff 8d 7c 22 00 00 48 8b 53 28 48 8b 43 30 48 8d b5 88 22 00
> 00 48 89 df <48> 89 42 08 48 89 10 48 b8 00 01 00 00 00 00 ad de 48 89
> 43 28
> [26672.553835] RIP: __remove_discard_cmd+0x6a/0xd0 RSP: ffff880813307e20
> [26672.553836] ---[ end trace 613553f7a4728b5b ]---
>
> On Tue, Aug 22, 2017 at 5:42 AM, Jaegeuk Kim <jaegeuk@xxxxxxxxxx> wrote:
>> On 08/18, Chao Yu wrote:
>>> Hi Jaegeuk,
>>>
>>> Sorry for the delay, the modification looks good to me. ;)
>>
>> We must avoid waking up discard thread caused by # of pending commands
>> which are never issued.
>>
>> From a73f8807248c2f42328a2204eab16a3b8d32c83e Mon Sep 17 00:00:00 2001
>> From: Chao Yu <yuchao0@xxxxxxxxxx>
>> Date: Mon, 7 Aug 2017 23:09:56 +0800
>> Subject: [PATCH] f2fs: introduce discard_granularity sysfs entry
>>
>> Commit d618ebaf0aa8 ("f2fs: enable small discard by default") enables
>> f2fs to issue 4K size discard in real-time discard mode. However, issuing
>> smaller discard may cost more lifetime but releasing less free space in
>> flash device. Since f2fs has ability of separating hot/cold data and
>> garbage collection, we can expect that small-sized invalid region would
>> expand soon with OPU, deletion or garbage collection on valid datas, so
>> it's better to delay or skip issuing smaller size discards, it could help
>> to reduce overmuch consumption of IO bandwidth and lifetime of flash
>> storage.
>>
>> This patch makes f2fs selectng 64K size as its default minimal
>> granularity, and issue discard with the size which is not smaller than
>> minimal granularity. Also it exposes discard granularity as sysfs entry
>> for configuration in different scenario.
>>
>> Jaegeuk Kim:
>> We must issue all the accumulated discard commands when fstrim is called.
>> So, I've added pend_list_tag[] to indicate whether we should issue the
>> commands or not. If tag sets P_ACTIVE or P_TRIM, we have to issue them.
>> P_TRIM is set once at a time, given fstrim trigger.
>> In addition, issue_discard_thread is calling too much due to the number of
>> discard commands remaining in the pending list. I added a timer to control
>> it likewise gc_thread.
>>
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
>> ---
>> Documentation/ABI/testing/sysfs-fs-f2fs | 9 ++++
>> fs/f2fs/f2fs.h | 12 +++++
>> fs/f2fs/segment.c | 91 ++++++++++++++++++++++++++++-----
>> fs/f2fs/sysfs.c | 23 +++++++++
>> 4 files changed, 121 insertions(+), 14 deletions(-)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
>> index 621da3fc56c5..11b7f4ebea7c 100644
>> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
>> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
>> @@ -57,6 +57,15 @@ Contact: "Jaegeuk Kim" <jaegeuk.kim@xxxxxxxxxxx>
>> Description:
>> Controls the issue rate of small discard commands.
>>
>> +What: /sys/fs/f2fs/<disk>/discard_granularity
>> +Date: July 2017
>> +Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
>> +Description:
>> + Controls discard granularity of inner discard thread, inner thread
>> + will not issue discards with size that is smaller than granularity.
>> + The unit size is one block, now only support configuring in range
>> + of [1, 512].
>> +
>> What: /sys/fs/f2fs/<disk>/max_victim_search
>> Date: January 2014
>> Contact: "Jaegeuk Kim" <jaegeuk.kim@xxxxxxxxxxx>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index e252e5bf9791..4b993961d81d 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -148,6 +148,8 @@ enum {
>> (BATCHED_TRIM_SEGMENTS(sbi) << (sbi)->log_blocks_per_seg)
>> #define MAX_DISCARD_BLOCKS(sbi) BLKS_PER_SEC(sbi)
>> #define DISCARD_ISSUE_RATE 8
>> +#define DEF_MIN_DISCARD_ISSUE_TIME 50 /* 50 ms, if exists */
>> +#define DEF_MAX_DISCARD_ISSUE_TIME 60000 /* 60 s, if no candidates */
>> #define DEF_CP_INTERVAL 60 /* 60 secs */
>> #define DEF_IDLE_INTERVAL 5 /* 5 secs */
>>
>> @@ -196,11 +198,18 @@ struct discard_entry {
>> unsigned char discard_map[SIT_VBLOCK_MAP_SIZE]; /* segment discard bitmap */
>> };
>>
>> +/* default discard granularity of inner discard thread, unit: block count */
>> +#define DEFAULT_DISCARD_GRANULARITY 16
>> +
>> /* max discard pend list number */
>> #define MAX_PLIST_NUM 512
>> #define plist_idx(blk_num) ((blk_num) >= MAX_PLIST_NUM ? \
>> (MAX_PLIST_NUM - 1) : (blk_num - 1))
>>
>> +#define P_ACTIVE 0x01
>> +#define P_TRIM 0x02
>> +#define plist_issue(tag) (((tag) & P_ACTIVE) || ((tag) & P_TRIM))
>> +
>> enum {
>> D_PREP,
>> D_SUBMIT,
>> @@ -236,11 +245,14 @@ struct discard_cmd_control {
>> struct task_struct *f2fs_issue_discard; /* discard thread */
>> struct list_head entry_list; /* 4KB discard entry list */
>> struct list_head pend_list[MAX_PLIST_NUM];/* store pending entries */
>> + unsigned char pend_list_tag[MAX_PLIST_NUM];/* tag for pending entries */
>> struct list_head wait_list; /* store on-flushing entries */
>> wait_queue_head_t discard_wait_queue; /* waiting queue for wake-up */
>> + unsigned int discard_wake; /* to wake up discard thread */
>> struct mutex cmd_lock;
>> unsigned int nr_discards; /* # of discards in the list */
>> unsigned int max_discards; /* max. discards to be issued */
>> + unsigned int discard_granularity; /* discard granularity */
>> unsigned int undiscard_blks; /* # of undiscard blocks */
>> atomic_t issued_discard; /* # of issued discard */
>> atomic_t issing_discard; /* # of issing discard */
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 05144b3a7f62..1387925a0d83 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -1016,32 +1016,65 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
>> return 0;
>> }
>>
>> -static void __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
>> +static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
>> {
>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>> struct list_head *pend_list;
>> struct discard_cmd *dc, *tmp;
>> struct blk_plug plug;
>> - int i, iter = 0;
>> + int iter = 0, issued = 0;
>> + int i;
>>
>> mutex_lock(&dcc->cmd_lock);
>> f2fs_bug_on(sbi,
>> !__check_rb_tree_consistence(sbi, &dcc->root));
>> blk_start_plug(&plug);
>> - for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
>> + for (i = MAX_PLIST_NUM - 1;
>> + i >= 0 && plist_issue(dcc->pend_list_tag[i]); i--) {
>> pend_list = &dcc->pend_list[i];
>> list_for_each_entry_safe(dc, tmp, pend_list, list) {
>> f2fs_bug_on(sbi, dc->state != D_PREP);
>>
>> - if (!issue_cond || is_idle(sbi))
>> + /* Hurry up to finish fstrim */
>> + if (dcc->pend_list_tag[i] & P_TRIM) {
>> + __submit_discard_cmd(sbi, dc);
>> + issued++;
>> + continue;
>> + }
>> +
>> + if (!issue_cond || is_idle(sbi)) {
>> + issued++;
>> __submit_discard_cmd(sbi, dc);
>> + }
>> if (issue_cond && iter++ > DISCARD_ISSUE_RATE)
>> goto out;
>> }
>> + if (list_empty(pend_list) && dcc->pend_list_tag[i] & P_TRIM)
>> + dcc->pend_list_tag[i] &= (~P_TRIM);
>> }
>> out:
>> blk_finish_plug(&plug);
>> mutex_unlock(&dcc->cmd_lock);
>> +
>> + return issued;
>> +}
>> +
>> +static void __drop_discard_cmd(struct f2fs_sb_info *sbi)
>> +{
>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>> + struct list_head *pend_list;
>> + struct discard_cmd *dc, *tmp;
>> + int i;
>> +
>> + mutex_lock(&dcc->cmd_lock);
>> + for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
>> + pend_list = &dcc->pend_list[i];
>> + list_for_each_entry_safe(dc, tmp, pend_list, list) {
>> + f2fs_bug_on(sbi, dc->state != D_PREP);
>> + __remove_discard_cmd(sbi, dc);
>> + }
>> + }
>> + mutex_unlock(&dcc->cmd_lock);
>> }
>>
>> static void __wait_one_discard_bio(struct f2fs_sb_info *sbi,
>> @@ -1126,34 +1159,56 @@ void stop_discard_thread(struct f2fs_sb_info *sbi)
>> void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
>> {
>> __issue_discard_cmd(sbi, false);
>> + __drop_discard_cmd(sbi);
>> __wait_discard_cmd(sbi, false);
>> }
>>
>> +static void mark_discard_range_all(struct f2fs_sb_info *sbi)
>> +{
>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>> + int i;
>> +
>> + mutex_lock(&dcc->cmd_lock);
>> + for (i = 0; i < MAX_PLIST_NUM; i++)
>> + dcc->pend_list_tag[i] |= P_TRIM;
>> + mutex_unlock(&dcc->cmd_lock);
>> +}
>> +
>> static int issue_discard_thread(void *data)
>> {
>> struct f2fs_sb_info *sbi = data;
>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>> wait_queue_head_t *q = &dcc->discard_wait_queue;
>> + unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
>> + int issued;
>>
>> set_freezable();
>>
>> do {
>> - wait_event_interruptible(*q, kthread_should_stop() ||
>> - freezing(current) ||
>> - atomic_read(&dcc->discard_cmd_cnt));
>> + wait_event_interruptible_timeout(*q,
>> + kthread_should_stop() || freezing(current) ||
>> + dcc->discard_wake,
>> + msecs_to_jiffies(wait_ms));
>> if (try_to_freeze())
>> continue;
>> if (kthread_should_stop())
>> return 0;
>>
>> + if (dcc->discard_wake)
>> + dcc->discard_wake = 0;
>> +
>> sb_start_intwrite(sbi->sb);
>>
>> - __issue_discard_cmd(sbi, true);
>> - __wait_discard_cmd(sbi, true);
>> + issued = __issue_discard_cmd(sbi, true);
>> + if (issued) {
>> + __wait_discard_cmd(sbi, true);
>> + wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
>> + } else {
>> + wait_ms = DEF_MAX_DISCARD_ISSUE_TIME;
>> + }
>>
>> sb_end_intwrite(sbi->sb);
>>
>> - congestion_wait(BLK_RW_SYNC, HZ/50);
>> } while (!kthread_should_stop());
>> return 0;
>> }
>> @@ -1344,7 +1399,8 @@ static void set_prefree_as_free_segments(struct f2fs_sb_info *sbi)
>>
>> void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>> {
>> - struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>> + struct list_head *head = &dcc->entry_list;
>> struct discard_entry *entry, *this;
>> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
>> unsigned long *prefree_map = dirty_i->dirty_segmap[PRE];
>> @@ -1426,11 +1482,12 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>> goto find_next;
>>
>> list_del(&entry->list);
>> - SM_I(sbi)->dcc_info->nr_discards -= total_len;
>> + dcc->nr_discards -= total_len;
>> kmem_cache_free(discard_entry_slab, entry);
>> }
>>
>> - wake_up(&SM_I(sbi)->dcc_info->discard_wait_queue);
>> + dcc->discard_wake = 1;
>> + wake_up_interruptible_all(&dcc->discard_wait_queue);
>> }
>>
>> static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
>> @@ -1448,9 +1505,13 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
>> if (!dcc)
>> return -ENOMEM;
>>
>> + dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
>> INIT_LIST_HEAD(&dcc->entry_list);
>> - for (i = 0; i < MAX_PLIST_NUM; i++)
>> + for (i = 0; i < MAX_PLIST_NUM; i++) {
>> INIT_LIST_HEAD(&dcc->pend_list[i]);
>> + if (i >= dcc->discard_granularity - 1)
>> + dcc->pend_list_tag[i] |= P_ACTIVE;
>> + }
>> INIT_LIST_HEAD(&dcc->wait_list);
>> mutex_init(&dcc->cmd_lock);
>> atomic_set(&dcc->issued_discard, 0);
>> @@ -2127,6 +2188,8 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
>>
>> schedule();
>> }
>> + /* It's time to issue all the filed discards */
>> + mark_discard_range_all(sbi);
>> out:
>> range->len = F2FS_BLK_TO_BYTES(cpc.trimmed);
>> return err;
>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
>> index c40e5d24df9f..4bcaa9059026 100644
>> --- a/fs/f2fs/sysfs.c
>> +++ b/fs/f2fs/sysfs.c
>> @@ -152,6 +152,27 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
>> spin_unlock(&sbi->stat_lock);
>> return count;
>> }
>> +
>> + if (!strcmp(a->attr.name, "discard_granularity")) {
>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>> + int i;
>> +
>> + if (t == 0 || t > MAX_PLIST_NUM)
>> + return -EINVAL;
>> + if (t == *ui)
>> + return count;
>> +
>> + mutex_lock(&dcc->cmd_lock);
>> + for (i = 0; i < MAX_PLIST_NUM; i++) {
>> + if (i >= t - 1)
>> + dcc->pend_list_tag[i] |= P_ACTIVE;
>> + else
>> + dcc->pend_list_tag[i] &= (~P_ACTIVE);
>> + }
>> + mutex_unlock(&dcc->cmd_lock);
>> + return count;
>> + }
>> +
>> *ui = t;
>>
>> if (!strcmp(a->attr.name, "iostat_enable") && *ui == 0)
>> @@ -248,6 +269,7 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle);
>> F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_urgent, gc_urgent);
>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
>> F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_small_discards, max_discards);
>> +F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity);
>> F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
>> @@ -290,6 +312,7 @@ static struct attribute *f2fs_attrs[] = {
>> ATTR_LIST(gc_urgent),
>> ATTR_LIST(reclaim_segments),
>> ATTR_LIST(max_small_discards),
>> + ATTR_LIST(discard_granularity),
>> ATTR_LIST(batched_trim_sections),
>> ATTR_LIST(ipu_policy),
>> ATTR_LIST(min_ipu_util),
>> --
>> 2.14.0.rc1.383.gd1ce394fe2-goog
>>
>>
>> ------------------------------------------------------------------------------
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