Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
On 2021/1/29 0:21, Jaegeuk Kim wrote:
On 01/20, Chao Yu wrote:
On 2021/1/20 3:06, Jaegeuk Kim wrote:
On 01/15, Chao Yu wrote:
On 2021/1/15 5:53, Jaegeuk Kim wrote:
On 12/30, Chao Yu wrote:
ThreadA ThreadB
- f2fs_ioc_start_atomic_write
- write
- f2fs_ioc_commit_atomic_write
- f2fs_commit_inmem_pages
- f2fs_drop_inmem_pages
- f2fs_drop_inmem_pages
- __revoke_inmem_pages
- f2fs_vm_page_mkwrite
- set_page_dirty
- tag ATOMIC_WRITTEN_PAGE and add page
to inmem_pages list
- clear_inode_flag(FI_ATOMIC_FILE)
- f2fs_vm_page_mkwrite
- set_page_dirty
- f2fs_update_dirty_page
- f2fs_trace_pid
- tag inmem page private to pid
Hmm, how about removing fs/f2fs/trace.c to make private more complicated
like this? I think we can get IO traces from tracepoints.
Hmm, actually, there is are issues, one is the trace IO, the other is the
race issue (atomic_start,commit,drop vs mkwrite) which can make isolation
semantics of transaction be broken.
Or can we avoid atomic file racing with file mmap?
Otherwise I think we should add i_mmap_sem to avoid the race.
No, we can't. We may need to find other way to check the race. :)
Well, any thoughts about this issue?
Thanks,
- atomic_start - file_mmap
- inode_lock
- if (FI_ATOMIC_FILE) return
- inode_lock
- if (FI_MMAP_FILE) return
Thanks,
- truncate
- f2fs_invalidate_page
- set page->mapping to NULL
then it will cause panic once we
access page->mapping
Are we hitting this, since page was referenced by in-mem list?
Yes, we hit this NULL point dereferencing issue when running fuzz tool,
but the condition is not the same, because in our product,
CONFIG_F2FS_IO_TRACE was not set.
Thanks,
The root cause is we missed to keep isolation of atomic write in the case
of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem
lock to avoid this issue.
Signed-off-by: Chao Yu
---
v2:
- use i_mmap_sem to avoid mkwrite racing with below flows:
* f2fs_ioc_start_atomic_write
* f2fs_drop_inmem_pages
* f2fs_commit_inmem_pages
fs/f2fs/file.c| 3 +++
fs/f2fs/segment.c | 7 +++
2 files changed, 10 insertions(+)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 4e6d4b9120a8..a48ec650d691 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
goto out;
down_write(_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(_I(inode)->i_mmap_sem);
/*
* Should wait end_io to count F2FS_WB_CP_DATA correctly by
@@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
inode->i_ino, get_dirty_pages(inode));
ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
if (ret) {
+ up_write(_I(inode)->i_mmap_sem);
up_write(_I(inode)->i_gc_rwsem[WRITE]);
goto out;
}
@@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
/* add inode in inmem_list first and set atomic_file */
set_inode_flag(inode, FI_ATOMIC_FILE);
clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
+ up_write(_I(inode)->i_mmap_sem);
up_write(_I(inode)->i_gc_rwsem[WRITE]);
f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d8570b0359f5..dab870d9faf6 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct f2fs_inode_info *fi = F2FS_I(inode);
+ down_write(_I(inode)->i_mmap_sem);
+
while (!list_empty(>inmem_pages)) {
mutex_lock(>inmem_lock);
__revoke_inmem_pages(inode, >inmem_pages,
@@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
sbi->atomic_files--;
}
spin_unlock(>inode_lock[ATOMIC_FILE]);
+
+ up_write(_I(inode)->i_mmap_sem);
}
void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
@@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode)
f2fs_balance_fs(sbi, true);
down_write(>i_gc_rwsem[WRITE]);
+
Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
On 01/20, Chao Yu wrote:
> On 2021/1/20 3:06, Jaegeuk Kim wrote:
> > On 01/15, Chao Yu wrote:
> > > On 2021/1/15 5:53, Jaegeuk Kim wrote:
> > > > On 12/30, Chao Yu wrote:
> > > > > ThreadA ThreadB
> > > > > - f2fs_ioc_start_atomic_write
> > > > > - write
> > > > > - f2fs_ioc_commit_atomic_write
> > > > >- f2fs_commit_inmem_pages
> > > > >- f2fs_drop_inmem_pages
> > > > >- f2fs_drop_inmem_pages
> > > > > - __revoke_inmem_pages
> > > > > - f2fs_vm_page_mkwrite
> > > > >- set_page_dirty
> > > > > - tag ATOMIC_WRITTEN_PAGE and
> > > > > add page
> > > > > to inmem_pages list
> > > > > - clear_inode_flag(FI_ATOMIC_FILE)
> > > > > - f2fs_vm_page_mkwrite
> > > > > - set_page_dirty
> > > > > - f2fs_update_dirty_page
> > > > > - f2fs_trace_pid
> > > > >- tag inmem page private
> > > > > to pid
> > > >
> > > > Hmm, how about removing fs/f2fs/trace.c to make private more complicated
> > > > like this? I think we can get IO traces from tracepoints.
> > >
> > > Hmm, actually, there is are issues, one is the trace IO, the other is the
> > > race issue (atomic_start,commit,drop vs mkwrite) which can make isolation
> > > semantics of transaction be broken.
> > >
> > > Or can we avoid atomic file racing with file mmap?
>
> Otherwise I think we should add i_mmap_sem to avoid the race.
>
> >
> > No, we can't. We may need to find other way to check the race. :)
>
> Well, any thoughts about this issue?
>
> Thanks,
>
> >
> > >
> > > - atomic_start- file_mmap
> > >- inode_lock
> > >- if (FI_ATOMIC_FILE) return
> > > - inode_lock
> > > - if (FI_MMAP_FILE) return
> > >
> > > Thanks,
> > >
> > > >
> > > > > - truncate
> > > > >- f2fs_invalidate_page
> > > > >- set page->mapping to NULL
> > > > > then it will cause panic once
> > > > > we
> > > > > access page->mapping
Are we hitting this, since page was referenced by in-mem list?
> > > > >
> > > > > The root cause is we missed to keep isolation of atomic write in the
> > > > > case
> > > > > of commit_atomic_write vs mkwrite, let commit_atomic_write helds
> > > > > i_mmap_sem
> > > > > lock to avoid this issue.
> > > > >
> > > > > Signed-off-by: Chao Yu
> > > > > ---
> > > > > v2:
> > > > > - use i_mmap_sem to avoid mkwrite racing with below flows:
> > > > >* f2fs_ioc_start_atomic_write
> > > > >* f2fs_drop_inmem_pages
> > > > >* f2fs_commit_inmem_pages
> > > > >
> > > > >fs/f2fs/file.c| 3 +++
> > > > >fs/f2fs/segment.c | 7 +++
> > > > >2 files changed, 10 insertions(+)
> > > > >
> > > > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > > > index 4e6d4b9120a8..a48ec650d691 100644
> > > > > --- a/fs/f2fs/file.c
> > > > > +++ b/fs/f2fs/file.c
> > > > > @@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct
> > > > > file *filp)
> > > > > goto out;
> > > > > down_write(_I(inode)->i_gc_rwsem[WRITE]);
> > > > > + down_write(_I(inode)->i_mmap_sem);
> > > > > /*
> > > > >* Should wait end_io to count F2FS_WB_CP_DATA correctly by
> > > > > @@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct
> > > > > file *filp)
> > > > > inode->i_ino, get_dirty_pages(inode));
> > > > > ret = filemap_write_and_wait_range(inode->i_mapping, 0,
> > > > > LLONG_MAX);
> > > > > if (ret) {
> > > > > + up_write(_I(inode)->i_mmap_sem);
> > > > > up_write(_I(inode)->i_gc_rwsem[WRITE]);
> > > > > goto out;
> > > > > }
> > > > > @@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct
> > > > > file *filp)
> > > > > /* add inode in inmem_list first and set atomic_file */
> > > > > set_inode_flag(inode, FI_ATOMIC_FILE);
> > > > > clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
> > > > > + up_write(_I(inode)->i_mmap_sem);
> > > > > up_write(_I(inode)->i_gc_rwsem[WRITE]);
> > > > > f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
> > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > index d8570b0359f5..dab870d9faf6 100644
> > > > > --- a/fs/f2fs/segment.c
> > > > > +++ b/fs/f2fs/segment.c
> > > > > @@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> > > > > struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > > > > struct
Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
On 2021/1/20 3:06, Jaegeuk Kim wrote:
On 01/15, Chao Yu wrote:
On 2021/1/15 5:53, Jaegeuk Kim wrote:
On 12/30, Chao Yu wrote:
ThreadA ThreadB
- f2fs_ioc_start_atomic_write
- write
- f2fs_ioc_commit_atomic_write
- f2fs_commit_inmem_pages
- f2fs_drop_inmem_pages
- f2fs_drop_inmem_pages
- __revoke_inmem_pages
- f2fs_vm_page_mkwrite
- set_page_dirty
- tag ATOMIC_WRITTEN_PAGE and add page
to inmem_pages list
- clear_inode_flag(FI_ATOMIC_FILE)
- f2fs_vm_page_mkwrite
- set_page_dirty
- f2fs_update_dirty_page
- f2fs_trace_pid
- tag inmem page private to pid
Hmm, how about removing fs/f2fs/trace.c to make private more complicated
like this? I think we can get IO traces from tracepoints.
Hmm, actually, there is are issues, one is the trace IO, the other is the
race issue (atomic_start,commit,drop vs mkwrite) which can make isolation
semantics of transaction be broken.
Or can we avoid atomic file racing with file mmap?
Otherwise I think we should add i_mmap_sem to avoid the race.
No, we can't. We may need to find other way to check the race. :)
Well, any thoughts about this issue?
Thanks,
- atomic_start - file_mmap
- inode_lock
- if (FI_ATOMIC_FILE) return
- inode_lock
- if (FI_MMAP_FILE) return
Thanks,
- truncate
- f2fs_invalidate_page
- set page->mapping to NULL
then it will cause panic once we
access page->mapping
The root cause is we missed to keep isolation of atomic write in the case
of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem
lock to avoid this issue.
Signed-off-by: Chao Yu
---
v2:
- use i_mmap_sem to avoid mkwrite racing with below flows:
* f2fs_ioc_start_atomic_write
* f2fs_drop_inmem_pages
* f2fs_commit_inmem_pages
fs/f2fs/file.c| 3 +++
fs/f2fs/segment.c | 7 +++
2 files changed, 10 insertions(+)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 4e6d4b9120a8..a48ec650d691 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
goto out;
down_write(_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(_I(inode)->i_mmap_sem);
/*
* Should wait end_io to count F2FS_WB_CP_DATA correctly by
@@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
inode->i_ino, get_dirty_pages(inode));
ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
if (ret) {
+ up_write(_I(inode)->i_mmap_sem);
up_write(_I(inode)->i_gc_rwsem[WRITE]);
goto out;
}
@@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
/* add inode in inmem_list first and set atomic_file */
set_inode_flag(inode, FI_ATOMIC_FILE);
clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
+ up_write(_I(inode)->i_mmap_sem);
up_write(_I(inode)->i_gc_rwsem[WRITE]);
f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d8570b0359f5..dab870d9faf6 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct f2fs_inode_info *fi = F2FS_I(inode);
+ down_write(_I(inode)->i_mmap_sem);
+
while (!list_empty(>inmem_pages)) {
mutex_lock(>inmem_lock);
__revoke_inmem_pages(inode, >inmem_pages,
@@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
sbi->atomic_files--;
}
spin_unlock(>inode_lock[ATOMIC_FILE]);
+
+ up_write(_I(inode)->i_mmap_sem);
}
void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
@@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode)
f2fs_balance_fs(sbi, true);
down_write(>i_gc_rwsem[WRITE]);
+ down_write(_I(inode)->i_mmap_sem);
f2fs_lock_op(sbi);
set_inode_flag(inode, FI_ATOMIC_COMMIT);
@@ -478,6 +483,8 @@ int f2fs_commit_inmem_pages(struct inode *inode)
clear_inode_flag(inode, FI_ATOMIC_COMMIT);
f2fs_unlock_op(sbi);
+
+ up_write(_I(inode)->i_mmap_sem);
up_write(>i_gc_rwsem[WRITE]);
Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
On 01/15, Chao Yu wrote:
> On 2021/1/15 5:53, Jaegeuk Kim wrote:
> > On 12/30, Chao Yu wrote:
> > > ThreadA ThreadB
> > > - f2fs_ioc_start_atomic_write
> > > - write
> > > - f2fs_ioc_commit_atomic_write
> > > - f2fs_commit_inmem_pages
> > > - f2fs_drop_inmem_pages
> > > - f2fs_drop_inmem_pages
> > >- __revoke_inmem_pages
> > > - f2fs_vm_page_mkwrite
> > >- set_page_dirty
> > > - tag ATOMIC_WRITTEN_PAGE and add page
> > > to inmem_pages list
> > >- clear_inode_flag(FI_ATOMIC_FILE)
> > > - f2fs_vm_page_mkwrite
> > > - set_page_dirty
> > > - f2fs_update_dirty_page
> > > - f2fs_trace_pid
> > >- tag inmem page private to pid
> >
> > Hmm, how about removing fs/f2fs/trace.c to make private more complicated
> > like this? I think we can get IO traces from tracepoints.
>
> Hmm, actually, there is are issues, one is the trace IO, the other is the
> race issue (atomic_start,commit,drop vs mkwrite) which can make isolation
> semantics of transaction be broken.
>
> Or can we avoid atomic file racing with file mmap?
No, we can't. We may need to find other way to check the race. :)
>
> - atomic_start- file_mmap
>- inode_lock
>- if (FI_ATOMIC_FILE) return
> - inode_lock
> - if (FI_MMAP_FILE) return
>
> Thanks,
>
> >
> > > - truncate
> > >- f2fs_invalidate_page
> > >- set page->mapping to NULL
> > > then it will cause panic once we
> > > access page->mapping
> > >
> > > The root cause is we missed to keep isolation of atomic write in the case
> > > of commit_atomic_write vs mkwrite, let commit_atomic_write helds
> > > i_mmap_sem
> > > lock to avoid this issue.
> > >
> > > Signed-off-by: Chao Yu
> > > ---
> > > v2:
> > > - use i_mmap_sem to avoid mkwrite racing with below flows:
> > > * f2fs_ioc_start_atomic_write
> > > * f2fs_drop_inmem_pages
> > > * f2fs_commit_inmem_pages
> > >
> > > fs/f2fs/file.c| 3 +++
> > > fs/f2fs/segment.c | 7 +++
> > > 2 files changed, 10 insertions(+)
> > >
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index 4e6d4b9120a8..a48ec650d691 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> > > *filp)
> > > goto out;
> > > down_write(_I(inode)->i_gc_rwsem[WRITE]);
> > > + down_write(_I(inode)->i_mmap_sem);
> > > /*
> > >* Should wait end_io to count F2FS_WB_CP_DATA correctly by
> > > @@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> > > *filp)
> > > inode->i_ino, get_dirty_pages(inode));
> > > ret = filemap_write_and_wait_range(inode->i_mapping, 0,
> > > LLONG_MAX);
> > > if (ret) {
> > > + up_write(_I(inode)->i_mmap_sem);
> > > up_write(_I(inode)->i_gc_rwsem[WRITE]);
> > > goto out;
> > > }
> > > @@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> > > *filp)
> > > /* add inode in inmem_list first and set atomic_file */
> > > set_inode_flag(inode, FI_ATOMIC_FILE);
> > > clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
> > > + up_write(_I(inode)->i_mmap_sem);
> > > up_write(_I(inode)->i_gc_rwsem[WRITE]);
> > > f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index d8570b0359f5..dab870d9faf6 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> > > struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > > struct f2fs_inode_info *fi = F2FS_I(inode);
> > > + down_write(_I(inode)->i_mmap_sem);
> > > +
> > > while (!list_empty(>inmem_pages)) {
> > > mutex_lock(>inmem_lock);
> > > __revoke_inmem_pages(inode, >inmem_pages,
> > > @@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> > > sbi->atomic_files--;
> > > }
> > > spin_unlock(>inode_lock[ATOMIC_FILE]);
> > > +
> > > + up_write(_I(inode)->i_mmap_sem);
> > > }
> > > void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
> > > @@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode)
> > > f2fs_balance_fs(sbi, true);
> > >
Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
On 2021/1/15 5:53, Jaegeuk Kim wrote:
On 12/30, Chao Yu wrote:
ThreadA ThreadB
- f2fs_ioc_start_atomic_write
- write
- f2fs_ioc_commit_atomic_write
- f2fs_commit_inmem_pages
- f2fs_drop_inmem_pages
- f2fs_drop_inmem_pages
- __revoke_inmem_pages
- f2fs_vm_page_mkwrite
- set_page_dirty
- tag ATOMIC_WRITTEN_PAGE and add page
to inmem_pages list
- clear_inode_flag(FI_ATOMIC_FILE)
- f2fs_vm_page_mkwrite
- set_page_dirty
- f2fs_update_dirty_page
- f2fs_trace_pid
- tag inmem page private to pid
Hmm, how about removing fs/f2fs/trace.c to make private more complicated
like this? I think we can get IO traces from tracepoints.
Hmm, actually, there is are issues, one is the trace IO, the other is the
race issue (atomic_start,commit,drop vs mkwrite) which can make isolation
semantics of transaction be broken.
Or can we avoid atomic file racing with file mmap?
- atomic_start - file_mmap
- inode_lock
- if (FI_ATOMIC_FILE) return
- inode_lock
- if (FI_MMAP_FILE) return
Thanks,
- truncate
- f2fs_invalidate_page
- set page->mapping to NULL
then it will cause panic once we
access page->mapping
The root cause is we missed to keep isolation of atomic write in the case
of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem
lock to avoid this issue.
Signed-off-by: Chao Yu
---
v2:
- use i_mmap_sem to avoid mkwrite racing with below flows:
* f2fs_ioc_start_atomic_write
* f2fs_drop_inmem_pages
* f2fs_commit_inmem_pages
fs/f2fs/file.c| 3 +++
fs/f2fs/segment.c | 7 +++
2 files changed, 10 insertions(+)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 4e6d4b9120a8..a48ec650d691 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
goto out;
down_write(_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(_I(inode)->i_mmap_sem);
/*
* Should wait end_io to count F2FS_WB_CP_DATA correctly by
@@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
inode->i_ino, get_dirty_pages(inode));
ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
if (ret) {
+ up_write(_I(inode)->i_mmap_sem);
up_write(_I(inode)->i_gc_rwsem[WRITE]);
goto out;
}
@@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
/* add inode in inmem_list first and set atomic_file */
set_inode_flag(inode, FI_ATOMIC_FILE);
clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
+ up_write(_I(inode)->i_mmap_sem);
up_write(_I(inode)->i_gc_rwsem[WRITE]);
f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d8570b0359f5..dab870d9faf6 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct f2fs_inode_info *fi = F2FS_I(inode);
+ down_write(_I(inode)->i_mmap_sem);
+
while (!list_empty(>inmem_pages)) {
mutex_lock(>inmem_lock);
__revoke_inmem_pages(inode, >inmem_pages,
@@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
sbi->atomic_files--;
}
spin_unlock(>inode_lock[ATOMIC_FILE]);
+
+ up_write(_I(inode)->i_mmap_sem);
}
void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
@@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode)
f2fs_balance_fs(sbi, true);
down_write(>i_gc_rwsem[WRITE]);
+ down_write(_I(inode)->i_mmap_sem);
f2fs_lock_op(sbi);
set_inode_flag(inode, FI_ATOMIC_COMMIT);
@@ -478,6 +483,8 @@ int f2fs_commit_inmem_pages(struct inode *inode)
clear_inode_flag(inode, FI_ATOMIC_COMMIT);
f2fs_unlock_op(sbi);
+
+ up_write(_I(inode)->i_mmap_sem);
up_write(>i_gc_rwsem[WRITE]);
return err;
--
2.29.2
.
Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
On 12/30, Chao Yu wrote:
> ThreadA ThreadB
> - f2fs_ioc_start_atomic_write
> - write
> - f2fs_ioc_commit_atomic_write
> - f2fs_commit_inmem_pages
> - f2fs_drop_inmem_pages
> - f2fs_drop_inmem_pages
> - __revoke_inmem_pages
> - f2fs_vm_page_mkwrite
>- set_page_dirty
> - tag ATOMIC_WRITTEN_PAGE and add page
> to inmem_pages list
> - clear_inode_flag(FI_ATOMIC_FILE)
> - f2fs_vm_page_mkwrite
> - set_page_dirty
> - f2fs_update_dirty_page
> - f2fs_trace_pid
>- tag inmem page private to pid
Hmm, how about removing fs/f2fs/trace.c to make private more complicated
like this? I think we can get IO traces from tracepoints.
> - truncate
>- f2fs_invalidate_page
>- set page->mapping to NULL
> then it will cause panic once we
> access page->mapping
>
> The root cause is we missed to keep isolation of atomic write in the case
> of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem
> lock to avoid this issue.
>
> Signed-off-by: Chao Yu
> ---
> v2:
> - use i_mmap_sem to avoid mkwrite racing with below flows:
> * f2fs_ioc_start_atomic_write
> * f2fs_drop_inmem_pages
> * f2fs_commit_inmem_pages
>
> fs/f2fs/file.c| 3 +++
> fs/f2fs/segment.c | 7 +++
> 2 files changed, 10 insertions(+)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 4e6d4b9120a8..a48ec650d691 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> *filp)
> goto out;
>
> down_write(_I(inode)->i_gc_rwsem[WRITE]);
> + down_write(_I(inode)->i_mmap_sem);
>
> /*
>* Should wait end_io to count F2FS_WB_CP_DATA correctly by
> @@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> *filp)
> inode->i_ino, get_dirty_pages(inode));
> ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
> if (ret) {
> + up_write(_I(inode)->i_mmap_sem);
> up_write(_I(inode)->i_gc_rwsem[WRITE]);
> goto out;
> }
> @@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> *filp)
> /* add inode in inmem_list first and set atomic_file */
> set_inode_flag(inode, FI_ATOMIC_FILE);
> clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
> + up_write(_I(inode)->i_mmap_sem);
> up_write(_I(inode)->i_gc_rwsem[WRITE]);
>
> f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index d8570b0359f5..dab870d9faf6 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> struct f2fs_inode_info *fi = F2FS_I(inode);
>
> + down_write(_I(inode)->i_mmap_sem);
> +
> while (!list_empty(>inmem_pages)) {
> mutex_lock(>inmem_lock);
> __revoke_inmem_pages(inode, >inmem_pages,
> @@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> sbi->atomic_files--;
> }
> spin_unlock(>inode_lock[ATOMIC_FILE]);
> +
> + up_write(_I(inode)->i_mmap_sem);
> }
>
> void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
> @@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode)
> f2fs_balance_fs(sbi, true);
>
> down_write(>i_gc_rwsem[WRITE]);
> + down_write(_I(inode)->i_mmap_sem);
>
> f2fs_lock_op(sbi);
> set_inode_flag(inode, FI_ATOMIC_COMMIT);
> @@ -478,6 +483,8 @@ int f2fs_commit_inmem_pages(struct inode *inode)
> clear_inode_flag(inode, FI_ATOMIC_COMMIT);
>
> f2fs_unlock_op(sbi);
> +
> + up_write(_I(inode)->i_mmap_sem);
> up_write(>i_gc_rwsem[WRITE]);
>
> return err;
> --
> 2.29.2
Re: [PATCH v2] f2fs: fix to keep isolation of atomic write
Hi Chao,
With a quick test, this patch causes down_write failure resulting in blocking
process. I didn't dig in the bug so, please check the code again. :P
On 12/30, Chao Yu wrote:
> ThreadA ThreadB
> - f2fs_ioc_start_atomic_write
> - write
> - f2fs_ioc_commit_atomic_write
> - f2fs_commit_inmem_pages
> - f2fs_drop_inmem_pages
> - f2fs_drop_inmem_pages
> - __revoke_inmem_pages
> - f2fs_vm_page_mkwrite
>- set_page_dirty
> - tag ATOMIC_WRITTEN_PAGE and add page
> to inmem_pages list
> - clear_inode_flag(FI_ATOMIC_FILE)
> - f2fs_vm_page_mkwrite
> - set_page_dirty
> - f2fs_update_dirty_page
> - f2fs_trace_pid
>- tag inmem page private to pid
> - truncate
>- f2fs_invalidate_page
>- set page->mapping to NULL
> then it will cause panic once we
> access page->mapping
>
> The root cause is we missed to keep isolation of atomic write in the case
> of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem
> lock to avoid this issue.
>
> Signed-off-by: Chao Yu
> ---
> v2:
> - use i_mmap_sem to avoid mkwrite racing with below flows:
> * f2fs_ioc_start_atomic_write
> * f2fs_drop_inmem_pages
> * f2fs_commit_inmem_pages
>
> fs/f2fs/file.c| 3 +++
> fs/f2fs/segment.c | 7 +++
> 2 files changed, 10 insertions(+)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 4e6d4b9120a8..a48ec650d691 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> *filp)
> goto out;
>
> down_write(_I(inode)->i_gc_rwsem[WRITE]);
> + down_write(_I(inode)->i_mmap_sem);
>
> /*
>* Should wait end_io to count F2FS_WB_CP_DATA correctly by
> @@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> *filp)
> inode->i_ino, get_dirty_pages(inode));
> ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
> if (ret) {
> + up_write(_I(inode)->i_mmap_sem);
> up_write(_I(inode)->i_gc_rwsem[WRITE]);
> goto out;
> }
> @@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file
> *filp)
> /* add inode in inmem_list first and set atomic_file */
> set_inode_flag(inode, FI_ATOMIC_FILE);
> clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
> + up_write(_I(inode)->i_mmap_sem);
> up_write(_I(inode)->i_gc_rwsem[WRITE]);
>
> f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index d8570b0359f5..dab870d9faf6 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> struct f2fs_inode_info *fi = F2FS_I(inode);
>
> + down_write(_I(inode)->i_mmap_sem);
> +
> while (!list_empty(>inmem_pages)) {
> mutex_lock(>inmem_lock);
> __revoke_inmem_pages(inode, >inmem_pages,
> @@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode)
> sbi->atomic_files--;
> }
> spin_unlock(>inode_lock[ATOMIC_FILE]);
> +
> + up_write(_I(inode)->i_mmap_sem);
> }
>
> void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
> @@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode)
> f2fs_balance_fs(sbi, true);
>
> down_write(>i_gc_rwsem[WRITE]);
> + down_write(_I(inode)->i_mmap_sem);
>
> f2fs_lock_op(sbi);
> set_inode_flag(inode, FI_ATOMIC_COMMIT);
> @@ -478,6 +483,8 @@ int f2fs_commit_inmem_pages(struct inode *inode)
> clear_inode_flag(inode, FI_ATOMIC_COMMIT);
>
> f2fs_unlock_op(sbi);
> +
> + up_write(_I(inode)->i_mmap_sem);
> up_write(>i_gc_rwsem[WRITE]);
>
> return err;
> --
> 2.29.2
