2022-03-02 08:53:26

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: avoid sb_start_intwrite during eviction

On 03/02, Chao Yu wrote:
> On 2022/3/1 12:48, Jaegeuk Kim wrote:
> > 1. waiting for f2fs_evict_inode
> > [ 5560.043945] __wait_on_freeing_inode+0xac/0xf0
> > [ 5560.045540] ? var_wake_function+0x30/0x30
> > [ 5560.047036] find_inode_fast+0x6d/0xc0
> > [ 5560.048473] iget_locked+0x79/0x230
> > [ 5560.049933] f2fs_iget+0x27/0x1200 [f2fs]
> > [ 5560.051496] f2fs_lookup+0x18c/0x3e0 [f2fs]
> > [ 5560.053069] __lookup_slow+0x84/0x150
> > [ 5560.054503] walk_component+0x141/0x1b0
> > [ 5560.055938] link_path_walk.part.0+0x23b/0x360
> > [ 5560.057541] ? end_bio_bh_io_sync+0x37/0x50
> > [ 5560.059086] path_parentat+0x3c/0x90
> > [ 5560.060492] filename_parentat+0xd7/0x1e0
> > [ 5560.062002] ? blk_mq_free_request+0x127/0x150
> > [ 5560.063576] do_renameat2+0xc1/0x5b0
> > --> sb_start_write(m->mnt_sb); -> __sb_start_write(sb, SB_FREEZE_WRITE);
> >
> > [ 5560.064999] ? __check_object_size+0x13f/0x150
> > [ 5560.066559] ? strncpy_from_user+0x44/0x150
> > [ 5560.068038] ? getname_flags.part.0+0x4c/0x1b0
> > [ 5560.069617] __x64_sys_renameat2+0x51/0x60
> >
> > 2. waiting for sb_start_intwrite -> __sb_start_write(sb, SB_FREEZE_FS);
>
> It's still not clear that why __sb_start_write(sb, SB_FREEZE_FS) will be blocked,
> as SB_FREEZE_FS and SB_FREEZE_WRITE points to different locks.

It seems I missed another call, thaw_super(), got SB_FREEZE_FS and then being
stuck to grab SB_FREEZE_WRITE.

>
> Thread A Thread B Thread C
> - rename
> - sb_start_write
> - __sb_start_write(SB_FREEZE_WRITE)
> ...
> - f2fs_lookup
> ...
> - __wait_on_freeing_inode
> - drop_slab
> - prune_icache_sb
> - inode_lru_isolate
> :inode->i_state |= I_FREEING
> - Is there any flow that it has already held
> SB_FREEZE_FS and try to lock SB_FREEZE_WRITE?
> - f2fs_evict_inode
> - __sb_start_write(SB_FREEZE_FS)
>
> Thanks,
>
> >
> > [ 5560.152447] percpu_rwsem_wait+0xaf/0x160
> > [ 5560.154000] ? percpu_down_write+0xd0/0xd0
> > [ 5560.155498] __percpu_down_read+0x4e/0x60
> > [ 5560.157000] f2fs_evict_inode+0x5a3/0x610 [f2fs]
> > [ 5560.158648] ? var_wake_function+0x30/0x30
> > [ 5560.160341] evict+0xd2/0x180
> > [ 5560.161728] prune_icache_sb+0x81/0xb0
> > --> inode_lru_isolate() -> inode->i_state |= I_FREEING;
> >
> > [ 5560.163179] super_cache_scan+0x169/0x1f0
> > [ 5560.164675] do_shrink_slab+0x145/0x2b0
> > [ 5560.166121] shrink_slab+0x186/0x2d0
> > [ 5560.167481] drop_slab_node+0x4a/0x90
> > [ 5560.168876] drop_slab+0x3e/0x80
> > [ 5560.170178] drop_caches_sysctl_handler+0x75/0x90
> > [ 5560.171761] proc_sys_call_handler+0x149/0x280
> > [ 5560.173328] proc_sys_write+0x13/0x20
> > [ 5560.174667] new_sync_write+0x117/0x1b0
> > [ 5560.176120] vfs_write+0x1d5/0x270
> > [ 5560.177409] ksys_write+0x67/0xe0
> >
> > Signed-off-by: Jaegeuk Kim <[email protected]>
> > ---
> > Note, I found this call stack.
> >
> > fs/f2fs/inode.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > index ab8e0c06c78c..882db4bd917b 100644
> > --- a/fs/f2fs/inode.c
> > +++ b/fs/f2fs/inode.c
> > @@ -778,7 +778,6 @@ void f2fs_evict_inode(struct inode *inode)
> > f2fs_remove_ino_entry(sbi, inode->i_ino, UPDATE_INO);
> > f2fs_remove_ino_entry(sbi, inode->i_ino, FLUSH_INO);
> > - sb_start_intwrite(inode->i_sb);
> > set_inode_flag(inode, FI_NO_ALLOC);
> > i_size_write(inode, 0);
> > retry:
> > @@ -809,7 +808,6 @@ void f2fs_evict_inode(struct inode *inode)
> > if (dquot_initialize_needed(inode))
> > set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
> > }
> > - sb_end_intwrite(inode->i_sb);
> > no_delete:
> > dquot_drop(inode);


2022-03-02 11:22:25

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: avoid sb_start_intwrite during eviction

On 03/01, Jaegeuk Kim wrote:
> On 03/02, Chao Yu wrote:
> > On 2022/3/1 12:48, Jaegeuk Kim wrote:
> > > 1. waiting for f2fs_evict_inode
> > > [ 5560.043945] __wait_on_freeing_inode+0xac/0xf0
> > > [ 5560.045540] ? var_wake_function+0x30/0x30
> > > [ 5560.047036] find_inode_fast+0x6d/0xc0
> > > [ 5560.048473] iget_locked+0x79/0x230
> > > [ 5560.049933] f2fs_iget+0x27/0x1200 [f2fs]
> > > [ 5560.051496] f2fs_lookup+0x18c/0x3e0 [f2fs]
> > > [ 5560.053069] __lookup_slow+0x84/0x150
> > > [ 5560.054503] walk_component+0x141/0x1b0
> > > [ 5560.055938] link_path_walk.part.0+0x23b/0x360
> > > [ 5560.057541] ? end_bio_bh_io_sync+0x37/0x50
> > > [ 5560.059086] path_parentat+0x3c/0x90
> > > [ 5560.060492] filename_parentat+0xd7/0x1e0
> > > [ 5560.062002] ? blk_mq_free_request+0x127/0x150
> > > [ 5560.063576] do_renameat2+0xc1/0x5b0
> > > --> sb_start_write(m->mnt_sb); -> __sb_start_write(sb, SB_FREEZE_WRITE);
> > >
> > > [ 5560.064999] ? __check_object_size+0x13f/0x150
> > > [ 5560.066559] ? strncpy_from_user+0x44/0x150
> > > [ 5560.068038] ? getname_flags.part.0+0x4c/0x1b0
> > > [ 5560.069617] __x64_sys_renameat2+0x51/0x60
> > >
> > > 2. waiting for sb_start_intwrite -> __sb_start_write(sb, SB_FREEZE_FS);
> >
> > It's still not clear that why __sb_start_write(sb, SB_FREEZE_FS) will be blocked,
> > as SB_FREEZE_FS and SB_FREEZE_WRITE points to different locks.
>
> It seems I missed another call, thaw_super(), got SB_FREEZE_FS and then being
> stuck to grab SB_FREEZE_WRITE.

Ah, sorry. freeze_super().

>
> >
> > Thread A Thread B Thread C
> > - rename
> > - sb_start_write
> > - __sb_start_write(SB_FREEZE_WRITE)
> > ...
> > - f2fs_lookup
> > ...
> > - __wait_on_freeing_inode
> > - drop_slab
> > - prune_icache_sb
> > - inode_lru_isolate
> > :inode->i_state |= I_FREEING
> > - Is there any flow that it has already held
> > SB_FREEZE_FS and try to lock SB_FREEZE_WRITE?
> > - f2fs_evict_inode
> > - __sb_start_write(SB_FREEZE_FS)
> >
> > Thanks,
> >
> > >
> > > [ 5560.152447] percpu_rwsem_wait+0xaf/0x160
> > > [ 5560.154000] ? percpu_down_write+0xd0/0xd0
> > > [ 5560.155498] __percpu_down_read+0x4e/0x60
> > > [ 5560.157000] f2fs_evict_inode+0x5a3/0x610 [f2fs]
> > > [ 5560.158648] ? var_wake_function+0x30/0x30
> > > [ 5560.160341] evict+0xd2/0x180
> > > [ 5560.161728] prune_icache_sb+0x81/0xb0
> > > --> inode_lru_isolate() -> inode->i_state |= I_FREEING;
> > >
> > > [ 5560.163179] super_cache_scan+0x169/0x1f0
> > > [ 5560.164675] do_shrink_slab+0x145/0x2b0
> > > [ 5560.166121] shrink_slab+0x186/0x2d0
> > > [ 5560.167481] drop_slab_node+0x4a/0x90
> > > [ 5560.168876] drop_slab+0x3e/0x80
> > > [ 5560.170178] drop_caches_sysctl_handler+0x75/0x90
> > > [ 5560.171761] proc_sys_call_handler+0x149/0x280
> > > [ 5560.173328] proc_sys_write+0x13/0x20
> > > [ 5560.174667] new_sync_write+0x117/0x1b0
> > > [ 5560.176120] vfs_write+0x1d5/0x270
> > > [ 5560.177409] ksys_write+0x67/0xe0
> > >
> > > Signed-off-by: Jaegeuk Kim <[email protected]>
> > > ---
> > > Note, I found this call stack.
> > >
> > > fs/f2fs/inode.c | 2 --
> > > 1 file changed, 2 deletions(-)
> > >
> > > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > > index ab8e0c06c78c..882db4bd917b 100644
> > > --- a/fs/f2fs/inode.c
> > > +++ b/fs/f2fs/inode.c
> > > @@ -778,7 +778,6 @@ void f2fs_evict_inode(struct inode *inode)
> > > f2fs_remove_ino_entry(sbi, inode->i_ino, UPDATE_INO);
> > > f2fs_remove_ino_entry(sbi, inode->i_ino, FLUSH_INO);
> > > - sb_start_intwrite(inode->i_sb);
> > > set_inode_flag(inode, FI_NO_ALLOC);
> > > i_size_write(inode, 0);
> > > retry:
> > > @@ -809,7 +808,6 @@ void f2fs_evict_inode(struct inode *inode)
> > > if (dquot_initialize_needed(inode))
> > > set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
> > > }
> > > - sb_end_intwrite(inode->i_sb);
> > > no_delete:
> > > dquot_drop(inode);
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

2022-03-02 19:34:38

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: avoid sb_start_intwrite during eviction

On 03/01, Jaegeuk Kim wrote:
> On 03/01, Jaegeuk Kim wrote:
> > On 03/02, Chao Yu wrote:
> > > On 2022/3/1 12:48, Jaegeuk Kim wrote:
> > > > 1. waiting for f2fs_evict_inode
> > > > [ 5560.043945] __wait_on_freeing_inode+0xac/0xf0
> > > > [ 5560.045540] ? var_wake_function+0x30/0x30
> > > > [ 5560.047036] find_inode_fast+0x6d/0xc0
> > > > [ 5560.048473] iget_locked+0x79/0x230
> > > > [ 5560.049933] f2fs_iget+0x27/0x1200 [f2fs]
> > > > [ 5560.051496] f2fs_lookup+0x18c/0x3e0 [f2fs]
> > > > [ 5560.053069] __lookup_slow+0x84/0x150
> > > > [ 5560.054503] walk_component+0x141/0x1b0
> > > > [ 5560.055938] link_path_walk.part.0+0x23b/0x360
> > > > [ 5560.057541] ? end_bio_bh_io_sync+0x37/0x50
> > > > [ 5560.059086] path_parentat+0x3c/0x90
> > > > [ 5560.060492] filename_parentat+0xd7/0x1e0
> > > > [ 5560.062002] ? blk_mq_free_request+0x127/0x150
> > > > [ 5560.063576] do_renameat2+0xc1/0x5b0
> > > > --> sb_start_write(m->mnt_sb); -> __sb_start_write(sb, SB_FREEZE_WRITE);
> > > >
> > > > [ 5560.064999] ? __check_object_size+0x13f/0x150
> > > > [ 5560.066559] ? strncpy_from_user+0x44/0x150
> > > > [ 5560.068038] ? getname_flags.part.0+0x4c/0x1b0
> > > > [ 5560.069617] __x64_sys_renameat2+0x51/0x60
> > > >
> > > > 2. waiting for sb_start_intwrite -> __sb_start_write(sb, SB_FREEZE_FS);
> > >
> > > It's still not clear that why __sb_start_write(sb, SB_FREEZE_FS) will be blocked,
> > > as SB_FREEZE_FS and SB_FREEZE_WRITE points to different locks.
> >
> > It seems I missed another call, thaw_super(), got SB_FREEZE_FS and then being
> > stuck to grab SB_FREEZE_WRITE.
>
> Ah, sorry. freeze_super().

Messed up. So, the lock order is SB_FREEZE_WRITE -> SB_FREEZE_FS in both cases.

>
> >
> > >
> > > Thread A Thread B Thread C
> > > - rename
> > > - sb_start_write
> > > - __sb_start_write(SB_FREEZE_WRITE)
> > > ...
> > > - f2fs_lookup
> > > ...
> > > - __wait_on_freeing_inode
> > > - drop_slab
> > > - prune_icache_sb
> > > - inode_lru_isolate
> > > :inode->i_state |= I_FREEING
> > > - Is there any flow that it has already held
> > > SB_FREEZE_FS and try to lock SB_FREEZE_WRITE?
> > > - f2fs_evict_inode
> > > - __sb_start_write(SB_FREEZE_FS)
> > >
> > > Thanks,
> > >
> > > >
> > > > [ 5560.152447] percpu_rwsem_wait+0xaf/0x160
> > > > [ 5560.154000] ? percpu_down_write+0xd0/0xd0
> > > > [ 5560.155498] __percpu_down_read+0x4e/0x60
> > > > [ 5560.157000] f2fs_evict_inode+0x5a3/0x610 [f2fs]
> > > > [ 5560.158648] ? var_wake_function+0x30/0x30
> > > > [ 5560.160341] evict+0xd2/0x180
> > > > [ 5560.161728] prune_icache_sb+0x81/0xb0
> > > > --> inode_lru_isolate() -> inode->i_state |= I_FREEING;
> > > >
> > > > [ 5560.163179] super_cache_scan+0x169/0x1f0
> > > > [ 5560.164675] do_shrink_slab+0x145/0x2b0
> > > > [ 5560.166121] shrink_slab+0x186/0x2d0
> > > > [ 5560.167481] drop_slab_node+0x4a/0x90
> > > > [ 5560.168876] drop_slab+0x3e/0x80
> > > > [ 5560.170178] drop_caches_sysctl_handler+0x75/0x90
> > > > [ 5560.171761] proc_sys_call_handler+0x149/0x280
> > > > [ 5560.173328] proc_sys_write+0x13/0x20
> > > > [ 5560.174667] new_sync_write+0x117/0x1b0
> > > > [ 5560.176120] vfs_write+0x1d5/0x270
> > > > [ 5560.177409] ksys_write+0x67/0xe0
> > > >
> > > > Signed-off-by: Jaegeuk Kim <[email protected]>
> > > > ---
> > > > Note, I found this call stack.
> > > >
> > > > fs/f2fs/inode.c | 2 --
> > > > 1 file changed, 2 deletions(-)
> > > >
> > > > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > > > index ab8e0c06c78c..882db4bd917b 100644
> > > > --- a/fs/f2fs/inode.c
> > > > +++ b/fs/f2fs/inode.c
> > > > @@ -778,7 +778,6 @@ void f2fs_evict_inode(struct inode *inode)
> > > > f2fs_remove_ino_entry(sbi, inode->i_ino, UPDATE_INO);
> > > > f2fs_remove_ino_entry(sbi, inode->i_ino, FLUSH_INO);
> > > > - sb_start_intwrite(inode->i_sb);
> > > > set_inode_flag(inode, FI_NO_ALLOC);
> > > > i_size_write(inode, 0);
> > > > retry:
> > > > @@ -809,7 +808,6 @@ void f2fs_evict_inode(struct inode *inode)
> > > > if (dquot_initialize_needed(inode))
> > > > set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
> > > > }
> > > > - sb_end_intwrite(inode->i_sb);
> > > > no_delete:
> > > > dquot_drop(inode);
> >
> >
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel