Re: [PATCH 2/3] fs/ntfs3: Remove locked argument in ntfs_set_ea

[Konstantin Komarov <almaz.alexandrovich@paragon-software.com>]

On 25.09.2021 11:49, Kari Argillander wrote:
> On Fri, Sep 24, 2021 at 07:15:50PM +0300, Konstantin Komarov wrote:
>> We always need to lock now, because locks became smaller
>> (see "Move ni_lock_dir and ni_unlock into ntfs_create_inode").
> 
> So basically this actually fixes that commit?
> 
> Fixes: d562e901f25d ("fs/ntfs3: Move ni_lock_dir and ni_unlock into ntfs_create_inode")
> 
> Or if you do not use fixes atleast use
> 
> d562e901f25d ("fs/ntfs3: Move ni_lock_dir and ni_unlock into ntfs_create_inode")
> 
> You can add these to your gitconfig
> 
> 	[core]
> 		abbrev = 12
> 	[pretty]
> 	        fixes = Fixes: %h (\"%s\")
> 		fixed = Fixes: %h (\"%s\")
> 
> And get this annotation with
> 	git show --pretty=fixes <sha>
> 
> Have some comments below also.
> 
>>
>> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
>> ---
>>  fs/ntfs3/xattr.c | 28 +++++++++++++---------------
>>  1 file changed, 13 insertions(+), 15 deletions(-)
>>
>> diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c
>> index 253a07d9aa7b..1ab109723b10 100644
>> --- a/fs/ntfs3/xattr.c
>> +++ b/fs/ntfs3/xattr.c
>> @@ -257,7 +257,7 @@ static int ntfs_get_ea(struct inode *inode, const char *name, size_t name_len,
>>  
>>  static noinline int ntfs_set_ea(struct inode *inode, const char *name,
>>  				size_t name_len, const void *value,
>> -				size_t val_size, int flags, int locked)
>> +				size_t val_size, int flags)
>>  {
>>  	struct ntfs_inode *ni = ntfs_i(inode);
>>  	struct ntfs_sb_info *sbi = ni->mi.sbi;
>> @@ -276,8 +276,7 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
>>  	u64 new_sz;
>>  	void *p;
>>  
>> -	if (!locked)
>> -		ni_lock(ni);
>> +	ni_lock(ni);
>>  
>>  	run_init(&ea_run);
>>  
>> @@ -465,8 +464,7 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
>>  	mark_inode_dirty(&ni->vfs_inode);
>>  
>>  out:
>> -	if (!locked)
>> -		ni_unlock(ni);
>> +	ni_unlock(ni);
>>  
>>  	run_close(&ea_run);
>>  	kfree(ea_all);
>> @@ -537,7 +535,7 @@ struct posix_acl *ntfs_get_acl(struct inode *inode, int type)
>>  
>>  static noinline int ntfs_set_acl_ex(struct user_namespace *mnt_userns,
>>  				    struct inode *inode, struct posix_acl *acl,
>> -				    int type, int locked)
>> +				    int type)
>>  {
>>  	const char *name;
>>  	size_t size, name_len;
>> @@ -594,7 +592,7 @@ static noinline int ntfs_set_acl_ex(struct user_namespace *mnt_userns,
>>  		flags = 0;
>>  	}
>>  
>> -	err = ntfs_set_ea(inode, name, name_len, value, size, flags, locked);
>> +	err = ntfs_set_ea(inode, name, name_len, value, size, flags);
>>  	if (err == -ENODATA && !size)
>>  		err = 0; /* Removing non existed xattr. */
>>  	if (!err)
>> @@ -612,7 +610,7 @@ static noinline int ntfs_set_acl_ex(struct user_namespace *mnt_userns,
>>  int ntfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
>>  		 struct posix_acl *acl, int type)
>>  {
>> -	return ntfs_set_acl_ex(mnt_userns, inode, acl, type, 0);
>> +	return ntfs_set_acl_ex(mnt_userns, inode, acl, type);
>>  }
>>  
>>  static int ntfs_xattr_get_acl(struct user_namespace *mnt_userns,
>> @@ -693,7 +691,7 @@ int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
>>  
>>  	if (default_acl) {
>>  		err = ntfs_set_acl_ex(mnt_userns, inode, default_acl,
>> -				      ACL_TYPE_DEFAULT, 1);
>> +				      ACL_TYPE_DEFAULT);
>>  		posix_acl_release(default_acl);
>>  	} else {
>>  		inode->i_default_acl = NULL;
>> @@ -704,7 +702,7 @@ int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
>>  	else {
>>  		if (!err)
>>  			err = ntfs_set_acl_ex(mnt_userns, inode, acl,
>> -					      ACL_TYPE_ACCESS, 1);
>> +					      ACL_TYPE_ACCESS);
>>  		posix_acl_release(acl);
>>  	}
>>  
>> @@ -988,7 +986,7 @@ static noinline int ntfs_setxattr(const struct xattr_handler *handler,
>>  	}
>>  #endif
>>  	/* Deal with NTFS extended attribute. */
>> -	err = ntfs_set_ea(inode, name, name_len, value, size, flags, 0);
>> +	err = ntfs_set_ea(inode, name, name_len, value, size, flags);
>>  
>>  out:
>>  	return err;
>> @@ -1006,26 +1004,26 @@ int ntfs_save_wsl_perm(struct inode *inode)
>>  
>>  	value = cpu_to_le32(i_uid_read(inode));
>>  	err = ntfs_set_ea(inode, "$LXUID", sizeof("$LXUID") - 1, &value,
>> -			  sizeof(value), 0, 0);
>> +			  sizeof(value), 0);
>>  	if (err)
>>  		goto out;
>>  
>>  	value = cpu_to_le32(i_gid_read(inode));
>>  	err = ntfs_set_ea(inode, "$LXGID", sizeof("$LXGID") - 1, &value,
>> -			  sizeof(value), 0, 0);
>> +			  sizeof(value), 0);
>>  	if (err)
>>  		goto out;
>>  
>>  	value = cpu_to_le32(inode->i_mode);
>>  	err = ntfs_set_ea(inode, "$LXMOD", sizeof("$LXMOD") - 1, &value,
>> -			  sizeof(value), 0, 0);
>> +			  sizeof(value), 0);
>>  	if (err)
>>  		goto out;
>>  
>>  	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
>>  		value = cpu_to_le32(inode->i_rdev);
>>  		err = ntfs_set_ea(inode, "$LXDEV", sizeof("$LXDEV") - 1, &value,
>> -				  sizeof(value), 0, 0);
>> +				  sizeof(value), 0);
> 
> Is this really that we can lock/unlock same lock 4 times in a row in a
> ntfs_set_ea? This does not feel correct. 
> 
>   Argillander
> 

How it was working before d562e901f25d 
"fs/ntfs3: Move ni_lock_dir and ni_unlock into ntfs_create_inode":

ntfs_create (lock mutex) =>
ntfs_create_inode =>
ntfs_save_wsl_perm (we are under lock here) =>
return to ntfs_create and unlock

How it works with d562e901f25d:

ntfs_create => 
ntfs_create_inode (lock in line 1201 file fs/ntfs3/inode.c 
and unlock in line 1557) => 
ntfs_save_wsl_perm (we aren't under lock here in line 1605)

So we need to lock 4 times because there are 4 ntfs_set_ea calls.
But now there can be done more work between those calls
in other threads, locks became more granular.

>>  		if (err)
>>  			goto out;
>>  	}
>> -- 
>> 2.33.0
>>
>>