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SubjectRe: [f2fs-dev] [PATCH] f2fs: remove circular locking between sb_internal and fs_reclaim
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On 2021/10/26 0:22, Daeho Jeong wrote:
> On Fri, Oct 22, 2021 at 8:32 AM Chao Yu <chao@kernel.org> wrote:
>>
>> On 2021/10/22 0:44, Daeho Jeong wrote:
>>> There is a deadlock between sb_internal lock (sb_start_intwrite()) and
>>> dquot related lock.
>>> It's because we call f2fs_truncate(), which eventually calls
>>> dquot_initialize(), while holding sb_internal lock.
>>> So, I called dquot_initialize() in advance to make the 2nd calling of
>>> it in f2fs_truncate() ineffective.
>>> This is similar with the thing in f2fs_evict_inode() in inode.c
>>
>> Well, if dquot_initialize() fails in f2fs_drop_inode(), will we still run
>> into deadlock?
>>
>
> Do you think the same issue is in f2fs_evict_inode() in inode.c?

Yes, I doubt the problem may also happen in f2fs_evict_inode() with below
callpath:

- evict_inode
- dquot_initialize failed
- sb_start_intwrite
- f2fs_truncate
- dquot_initialize lock dqio_sem

How about this?

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
old mode 100644
new mode 100755
index b24b9bc..0e49593
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -728,6 +728,7 @@ enum {
FI_ENABLE_COMPRESS, /* enable compression in "user" compression mode */
FI_COMPRESS_RELEASED, /* compressed blocks were released */
FI_ALIGNED_WRITE, /* enable aligned write */
+ FI_QUOTA_INIT_FAIL, /* inidicate failed to initialize quota in drop_inode()/evict_inode() */
FI_MAX, /* max flag, never be used */
};

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
old mode 100644
new mode 100755
index 13deae0..2fb53f54
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -789,9 +789,11 @@ int f2fs_truncate(struct inode *inode)
return -EIO;
}

- err = dquot_initialize(inode);
- if (err)
- return err;
+ if (!is_inode_flag_set(inode, FI_QUOTA_INIT_FAIL)) {
+ err = dquot_initialize(inode);
+ if (err)
+ return err;
+ }

/* we should check inline_data size */
if (!f2fs_may_inline_data(inode)) {
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
old mode 100644
new mode 100755
index 1213f15..16cf50c
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -758,6 +758,7 @@ void f2fs_evict_inode(struct inode *inode)
if (err) {
err = 0;
set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+ set_inode_flag(inode, FI_QUOTA_INIT_FAIL);
}

f2fs_remove_ino_entry(sbi, inode->i_ino, APPEND_INO);
@@ -770,6 +771,8 @@ void f2fs_evict_inode(struct inode *inode)
retry:
if (F2FS_HAS_BLOCKS(inode))
err = f2fs_truncate(inode);
+ if (is_inode_flag_set(inode, FI_QUOTA_INIT_FAIL))
+ clear_inode_flag(inode, FI_QUOTA_INIT_FAIL);

if (time_to_inject(sbi, FAULT_EVICT_INODE)) {
f2fs_show_injection_info(sbi, FAULT_EVICT_INODE);
Thanks,


> In fact, I picked up the idea from here.
>
> err = dquot_initialize(inode);
> if (err) {
> err = 0;
> set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
> }
>
> f2fs_remove_ino_entry(sbi, inode->i_ino, APPEND_INO);
> 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:
> if (F2FS_HAS_BLOCKS(inode))
> err = f2fs_truncate(inode);
>

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