Re: [f2fs-dev] [PATCH v2] f2fs: avoid stucking GC due to atomic write
On 04/27, Chao Yu wrote:
> On 2018/4/26 23:54, Jaegeuk Kim wrote:
> > On 04/24, Chao Yu wrote:
> >> f2fs doesn't allow abuse on atomic write class interface, so except
> >> limiting in-mem pages' total memory usage capacity, we need to limit
> >> atomic-write usage as well when filesystem is seriously fragmented,
> >> otherwise we may run into infinite loop during foreground GC because
> >> target blocks in victim segment are belong to atomic opened file for
> >> long time.
> >
> > How about using fi->i_gc_failure likewise pin_file?
>
> OK, how about changing it to array fi->i_gc_failure[MAX_GC_FAILURE], and
> change
> the type to unsigned long long to avoid overflow?
It'd be enough to share i_gc_failure between the types, IMO.
>
> enum {
> GC_FAILURE_PIN,
> GC_FAILURE_ATOMIC,
> MAX_GC_FAILURE
> }
>
> Thanks,
>
> >
> >>
> >> Now, we will detect failure due to atomic write in foreground GC, if
> >> the count exceeds threshold, we will drop all atomic written data in
> >> cache, by this, I expect it can keep our system running safely to
> >> prevent Dos attack.
> >>
> >> In addition, his patch adds to show GC skip information in debugfs,
> >> now it just shows count of skipped caused by atomic write.
> >>
> >> Signed-off-by: Chao Yu
> >> ---
> >> v2:
> >> - add to show skip info in debugfs.
> >> fs/f2fs/debug.c | 8
> >> fs/f2fs/f2fs.h| 2 ++
> >> fs/f2fs/file.c| 5 +
> >> fs/f2fs/gc.c | 29 +
> >> fs/f2fs/gc.h | 3 +++
> >> fs/f2fs/segment.c | 1 +
> >> fs/f2fs/segment.h | 2 ++
> >> 7 files changed, 46 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
> >> index 0fbd674c66fb..607b258a9b61 100644
> >> --- a/fs/f2fs/debug.c
> >> +++ b/fs/f2fs/debug.c
> >> @@ -104,6 +104,10 @@ static void update_general_status(struct f2fs_sb_info
> >> *sbi)
> >>si->avail_nids = NM_I(sbi)->available_nids;
> >>si->alloc_nids = NM_I(sbi)->nid_cnt[PREALLOC_NID];
> >>si->bg_gc = sbi->bg_gc;
> >> + si->skipped_atomic_files[BG_GC] =
> >> + sbi->gc_thread->skipped_atomic_files[BG_GC];
> >> + si->skipped_atomic_files[FG_GC] =
> >> + sbi->gc_thread->skipped_atomic_files[FG_GC];
> >>si->util_free = (int)(free_user_blocks(sbi) >> sbi->log_blocks_per_seg)
> >>* 100 / (int)(sbi->user_block_count >> sbi->log_blocks_per_seg)
> >>/ 2;
> >> @@ -341,6 +345,10 @@ static int stat_show(struct seq_file *s, void *v)
> >>si->bg_data_blks);
> >>seq_printf(s, " - node blocks : %d (%d)\n", si->node_blks,
> >>si->bg_node_blks);
> >> + seq_printf(s, "Skipped : atomic write %llu (%llu)\n",
> >> + si->skipped_atomic_files[BG_GC] +
> >> + si->skipped_atomic_files[FG_GC],
> >> + si->skipped_atomic_files[BG_GC]);
> >>seq_puts(s, "\nExtent Cache:\n");
> >>seq_printf(s, " - Hit Count: L1-1:%llu L1-2:%llu L2:%llu\n",
> >>si->hit_largest, si->hit_cached,
> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >> index 75d3b4875429..c2b92cb377c6 100644
> >> --- a/fs/f2fs/f2fs.h
> >> +++ b/fs/f2fs/f2fs.h
> >> @@ -2254,6 +2254,7 @@ enum {
> >>FI_EXTRA_ATTR, /* indicate file has extra attribute */
> >>FI_PROJ_INHERIT,/* indicate file inherits projectid */
> >>FI_PIN_FILE,/* indicate file should not be gced */
> >> + FI_ATOMIC_REVOKE_REQUEST,/* indicate atomic committed data has been
> >> dropped */
> >> };
> >>
> >> static inline void __mark_inode_dirty_flag(struct inode *inode,
> >> @@ -3010,6 +3011,7 @@ struct f2fs_stat_info {
> >>int bg_node_segs, bg_data_segs;
> >>int tot_blks, data_blks, node_blks;
> >>int bg_data_blks, bg_node_blks;
> >> + unsigned long long skipped_atomic_files[2];
> >>int curseg[NR_CURSEG_TYPE];
> >>int cursec[NR_CURSEG_TYPE];
> >>int curzone[NR_CURSEG_TYPE];
> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> >> index a352804af244..0cfa65c21d3f 100644
> >> --- a/fs/f2fs/file.c
> >> +++ b/fs/f2fs/file.c
> >> @@ -1702,6 +1702,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> >> *filp)
> >> skip_flush:
> >>set_inode_flag(inode, FI_HOT_DATA);
> >>set_inode_flag(inode, FI_ATOMIC_FILE);
> >> + clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
> >>f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
> >>
> >>F2FS_I(inode)->inmem_task = current;
> >> @@ -1750,6 +1751,10 @@ static int f2fs_ioc_commit_atomic_write(struct file
> >> *filp)
> >>ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 1, false);
> >>}
> >> err_out:
> >> + if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST)) {
> >> + clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
> >> + ret = -EINVAL;
> >> + }
> >>up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
Re: [f2fs-dev] [PATCH v2] f2fs: fix to avoid race during access gc_thread pointer
On 04/27, Chao Yu wrote:
> On 2018/4/27 0:03, Jaegeuk Kim wrote:
> > On 04/24, Chao Yu wrote:
> >> Thread A Thread BThread C
> >> - f2fs_remount
> >> - stop_gc_thread
> >>- f2fs_sbi_store
> >>- issue_discard_thread
> >>sbi->gc_thread = NULL;
> >> sbi->gc_thread->gc_wake = 1
> >> access
> >> sbi->gc_thread->gc_urgent
> >>
> >> Previously, we allocate memory for sbi->gc_thread based on background
> >> gc thread mount option, the memory can be released if we turn off
> >> that mount option, but still there are several places access gc_thread
> >> pointer without considering race condition, result in NULL point
> >> dereference.
> >
> > Do we just need to check &sb->s_umount in f2fs_sbi_store() and
>
> Better,
>
> > issue_discard_thread?
>
> There is more cases can be called from different scenarios:
> - select_policy()
> - need_SSR()
No? They should be blocked by remount(2).
>
> Thanks,
>
> >
> >>
> >> In order to fix this issue, keep gc_thread structure valid in sbi all
> >> the time instead of alloc/free it dynamically.
> >>
> >> In addition, add a rw semaphore to exclude rw operation in fields of
> >> gc_thread.
> >>
> >> Signed-off-by: Chao Yu
> >> ---
> >> v2:
> >> - add a rw semaphore to exclude rw operation suggested by Jaegeuk.
> >> fs/f2fs/debug.c | 3 +--
> >> fs/f2fs/f2fs.h| 9 ++-
> >> fs/f2fs/gc.c | 78
> >> ---
> >> fs/f2fs/gc.h | 1 +
> >> fs/f2fs/segment.c | 10 +--
> >> fs/f2fs/super.c | 26 +--
> >> fs/f2fs/sysfs.c | 26 ++-
> >> 7 files changed, 107 insertions(+), 46 deletions(-)
> >>
> >> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
> >> index a66107b5cfff..0fbd674c66fb 100644
> >> --- a/fs/f2fs/debug.c
> >> +++ b/fs/f2fs/debug.c
> >> @@ -221,8 +221,7 @@ static void update_mem_info(struct f2fs_sb_info *sbi)
> >>si->cache_mem = 0;
> >>
> >>/* build gc */
> >> - if (sbi->gc_thread)
> >> - si->cache_mem += sizeof(struct f2fs_gc_kthread);
> >> + si->cache_mem += sizeof(struct f2fs_gc_kthread);
> >>
> >>/* build merge flush thread */
> >>if (SM_I(sbi)->fcc_info)
> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >> index 8f3ad9662d13..75d3b4875429 100644
> >> --- a/fs/f2fs/f2fs.h
> >> +++ b/fs/f2fs/f2fs.h
> >> @@ -1412,6 +1412,11 @@ static inline struct sit_info *SIT_I(struct
> >> f2fs_sb_info *sbi)
> >>return (struct sit_info *)(SM_I(sbi)->sit_info);
> >> }
> >>
> >> +static inline struct f2fs_gc_kthread *GC_I(struct f2fs_sb_info *sbi)
> >> +{
> >> + return (struct f2fs_gc_kthread *)(sbi->gc_thread);
> >> +}
> >> +
> >> static inline struct free_segmap_info *FREE_I(struct f2fs_sb_info *sbi)
> >> {
> >>return (struct free_segmap_info *)(SM_I(sbi)->free_info);
> >> @@ -2954,8 +2959,10 @@ bool f2fs_overwrite_io(struct inode *inode, loff_t
> >> pos, size_t len);
> >> /*
> >> * gc.c
> >> */
> >> +int init_gc_context(struct f2fs_sb_info *sbi);
> >> +void destroy_gc_context(struct f2fs_sb_info * sbi);
> >> int start_gc_thread(struct f2fs_sb_info *sbi);
> >> -void stop_gc_thread(struct f2fs_sb_info *sbi);
> >> +bool stop_gc_thread(struct f2fs_sb_info *sbi);
> >> block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode);
> >> int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background,
> >>unsigned int segno);
> >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> >> index 70418b34c5f6..2febb84b2fd6 100644
> >> --- a/fs/f2fs/gc.c
> >> +++ b/fs/f2fs/gc.c
> >> @@ -26,8 +26,8 @@
> >> static int gc_thread_func(void *data)
> >> {
> >>struct f2fs_sb_info *sbi = data;
> >> - struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
> >> - wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
> >> + struct f2fs_gc_kthread *gc_th = GC_I(sbi);
> >> + wait_queue_head_t *wq = &gc_th->gc_wait_queue_head;
> >>unsigned int wait_ms;
> >>
> >>wait_ms = gc_th->min_sleep_time;
> >> @@ -114,17 +114,15 @@ static int gc_thread_func(void *data)
> >>return 0;
> >> }
> >>
> >> -int start_gc_thread(struct f2fs_sb_info *sbi)
> >> +int init_gc_context(struct f2fs_sb_info *sbi)
> >> {
> >>struct f2fs_gc_kthread *gc_th;
> >> - dev_t dev = sbi->sb->s_bdev->bd_dev;
> >> - int err = 0;
> >>
> >>gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
> >> - if (!gc_th) {
> >> - err = -ENOMEM;
> >> - goto out;
> >> - }
> >> + if (!gc_th)
> >> + return -ENOMEM;
> >> +
> >> + gc_th->f2fs_gc_task = NULL;
> >>
> >>gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
> >>gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
> >> @@ -135,35 +133,59 @@ int start_gc_thread(struct f2fs_sb_info *sbi)
> >>gc_th->gc_urgent = 0;
> >>
Re: [f2fs-dev] [PATCH v2] f2fs: fix to avoid race during access gc_thread pointer
On 04/27, Chao Yu wrote:
> On 2018/4/27 10:04, Chao Yu wrote:
> > On 2018/4/27 0:03, Jaegeuk Kim wrote:
> >> On 04/24, Chao Yu wrote:
> >>> Thread A Thread BThread C
> >>> - f2fs_remount
> >>> - stop_gc_thread
> >>> - f2fs_sbi_store
> >>> - issue_discard_thread
> >>>sbi->gc_thread = NULL;
> >>> sbi->gc_thread->gc_wake = 1
> >>> access
> >>> sbi->gc_thread->gc_urgent
> >>>
> >>> Previously, we allocate memory for sbi->gc_thread based on background
> >>> gc thread mount option, the memory can be released if we turn off
> >>> that mount option, but still there are several places access gc_thread
> >>> pointer without considering race condition, result in NULL point
> >>> dereference.
> >>
> >> Do we just need to check &sb->s_umount in f2fs_sbi_store() and
> >
> > Better,
> >
> >> issue_discard_thread?
> >
> > There is more cases can be called from different scenarios:
> > - select_policy()
> > - need_SSR()
>
> BTW, do you agree with introducing {init,destroy}_gc_context as the patch
> does?
I don't think so. The issue only requires mutex() in sysfs/discard_thread.
>
> Thanks,
>
> >
> > Thanks,
> >
> >>
> >>>
> >>> In order to fix this issue, keep gc_thread structure valid in sbi all
> >>> the time instead of alloc/free it dynamically.
> >>>
> >>> In addition, add a rw semaphore to exclude rw operation in fields of
> >>> gc_thread.
> >>>
> >>> Signed-off-by: Chao Yu
> >>> ---
> >>> v2:
> >>> - add a rw semaphore to exclude rw operation suggested by Jaegeuk.
> >>> fs/f2fs/debug.c | 3 +--
> >>> fs/f2fs/f2fs.h| 9 ++-
> >>> fs/f2fs/gc.c | 78
> >>> ---
> >>> fs/f2fs/gc.h | 1 +
> >>> fs/f2fs/segment.c | 10 +--
> >>> fs/f2fs/super.c | 26 +--
> >>> fs/f2fs/sysfs.c | 26 ++-
> >>> 7 files changed, 107 insertions(+), 46 deletions(-)
> >>>
> >>> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
> >>> index a66107b5cfff..0fbd674c66fb 100644
> >>> --- a/fs/f2fs/debug.c
> >>> +++ b/fs/f2fs/debug.c
> >>> @@ -221,8 +221,7 @@ static void update_mem_info(struct f2fs_sb_info *sbi)
> >>> si->cache_mem = 0;
> >>>
> >>> /* build gc */
> >>> - if (sbi->gc_thread)
> >>> - si->cache_mem += sizeof(struct f2fs_gc_kthread);
> >>> + si->cache_mem += sizeof(struct f2fs_gc_kthread);
> >>>
> >>> /* build merge flush thread */
> >>> if (SM_I(sbi)->fcc_info)
> >>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >>> index 8f3ad9662d13..75d3b4875429 100644
> >>> --- a/fs/f2fs/f2fs.h
> >>> +++ b/fs/f2fs/f2fs.h
> >>> @@ -1412,6 +1412,11 @@ static inline struct sit_info *SIT_I(struct
> >>> f2fs_sb_info *sbi)
> >>> return (struct sit_info *)(SM_I(sbi)->sit_info);
> >>> }
> >>>
> >>> +static inline struct f2fs_gc_kthread *GC_I(struct f2fs_sb_info *sbi)
> >>> +{
> >>> + return (struct f2fs_gc_kthread *)(sbi->gc_thread);
> >>> +}
> >>> +
> >>> static inline struct free_segmap_info *FREE_I(struct f2fs_sb_info *sbi)
> >>> {
> >>> return (struct free_segmap_info *)(SM_I(sbi)->free_info);
> >>> @@ -2954,8 +2959,10 @@ bool f2fs_overwrite_io(struct inode *inode, loff_t
> >>> pos, size_t len);
> >>> /*
> >>> * gc.c
> >>> */
> >>> +int init_gc_context(struct f2fs_sb_info *sbi);
> >>> +void destroy_gc_context(struct f2fs_sb_info * sbi);
> >>> int start_gc_thread(struct f2fs_sb_info *sbi);
> >>> -void stop_gc_thread(struct f2fs_sb_info *sbi);
> >>> +bool stop_gc_thread(struct f2fs_sb_info *sbi);
> >>> block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode);
> >>> int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background,
> >>> unsigned int segno);
> >>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> >>> index 70418b34c5f6..2febb84b2fd6 100644
> >>> --- a/fs/f2fs/gc.c
> >>> +++ b/fs/f2fs/gc.c
> >>> @@ -26,8 +26,8 @@
> >>> static int gc_thread_func(void *data)
> >>> {
> >>> struct f2fs_sb_info *sbi = data;
> >>> - struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
> >>> - wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
> >>> + struct f2fs_gc_kthread *gc_th = GC_I(sbi);
> >>> + wait_queue_head_t *wq = &gc_th->gc_wait_queue_head;
> >>> unsigned int wait_ms;
> >>>
> >>> wait_ms = gc_th->min_sleep_time;
> >>> @@ -114,17 +114,15 @@ static int gc_thread_func(void *data)
> >>> return 0;
> >>> }
> >>>
> >>> -int start_gc_thread(struct f2fs_sb_info *sbi)
> >>> +int init_gc_context(struct f2fs_sb_info *sbi)
> >>> {
> >>> struct f2fs_gc_kthread *gc_th;
> >>> - dev_t dev = sbi->sb->s_bdev->bd_dev;
> >>> - int err = 0;
> >>>
> >>> gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
> >>> - if (!gc_th) {
> >>> - err = -ENOMEM;
> >>> - goto out;
> >>> - }
> >>> + if (!gc_th)
> >>> + return -ENOMEM;
> >>> +
> >>>
Re: [f2fs-dev] [RFC PATCH] f2fs-tools: introduce tune.f2fs
On 04/27, Chao Yu wrote: > On 2018/4/27 0:13, Jaegeuk Kim wrote: > > On 04/26, Junling Zheng wrote: > >> Ping... > >> > >> On 2018/4/23 15:32, Junling Zheng wrote: > >>> Introduce tune.f2fs tool to change the f2fs parameters. > >>> Currently this tool only supports adding or removing encrypt > >>> feature bit in superblock. > > > > What is the purpose of this empty tune.f2fs? How can we say we have this > > tool to users? You have to design what kind of things to support first. > > I checked very initial tune2fs.c, it only supports very few parameters tuning > functionality, but, can not say that is a bad start to introduce the misc > tool. > > + fprintf (stderr, "Usage: %s [-c max-mounts-count] [-e > errors-behavior] " > +"[-i interval[d|m]]\n" > +"\t[-l] [-m reserved-blocks-percent] device\n", > program_name); I don't think We have to follow that. > > Maybe tuning 1. extension list, 2. multi device name later? just guess. First of all, does it make sense to unset feature bits? I don't think so. Agreed to your suggestion where: 1. feature set - enable system quota 2. extension list 3. multi device name -- which may be really big trial > > Using fsck.f2fs to tune parameter, IMO, maybe a little confuse for user to > understand the tool's functionality. > > Thanks, -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
