From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relaydlg-01.paragon-software.com (relaydlg-01.paragon-software.com [81.5.88.159]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EDD1F29CA for ; Tue, 28 Sep 2021 18:01:41 +0000 (UTC) Received: from dlg2.mail.paragon-software.com (vdlg-exch-02.paragon-software.com [172.30.1.105]) by relaydlg-01.paragon-software.com (Postfix) with ESMTPS id 2D5DE82156; Tue, 28 Sep 2021 21:01:40 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paragon-software.com; s=mail; t=1632852100; bh=qY3fyImBzSHuyEURvksncUEzAUF8i72Li2tfjGn8KBg=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=l77m+WLPNDvftSY1Ou2ysosltu0/ZL9Viob214rG5yvfxoA4B1YrnR54w0HDbepjQ YrmrsV9lT0oGO2m+K8wlw2KIdyfjPGeHg99yYpwSJI4iF1UkecqLG2uIkiVT+p7oLj 1mk3a/3d4lzBRFRC7pzzTRhymKa6wT7FrJeTuDJU= Received: from [192.168.211.85] (192.168.211.85) by vdlg-exch-02.paragon-software.com (172.30.1.105) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 28 Sep 2021 21:01:39 +0300 Message-ID: Date: Tue, 28 Sep 2021 21:01:38 +0300 Precedence: bulk X-Mailing-List: ntfs3@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.1 Subject: Re: [PATCH 2/3] fs/ntfs3: Remove locked argument in ntfs_set_ea Content-Language: en-US To: Kari Argillander CC: , , References:

<20210925084901.mvlxt442jvy2et7u@kari-VirtualBox> <816442f2-a79f-68cf-f107-9770a66f3acc@paragon-software.com> <20210927191005.zcebctlxfsqutgkh@kari-VirtualBox> From: Konstantin Komarov In-Reply-To: <20210927191005.zcebctlxfsqutgkh@kari-VirtualBox> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.211.85] X-ClientProxiedBy: vdlg-exch-02.paragon-software.com (172.30.1.105) To vdlg-exch-02.paragon-software.com (172.30.1.105) On 27.09.2021 22:10, Kari Argillander wrote: > On Mon, Sep 27, 2021 at 06:10:00PM +0300, Konstantin Komarov wrote: >> >> >> 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 >>> >>> Have some comments below also. >>> >>>> >>>> Signed-off-by: Konstantin Komarov >>>> --- >>>> 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) > > Maybe we should leave int locked and ... > >>>> + 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) >>>> > > do lock here and ... > >>>> 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); > > unlock here. Of course unlock also in error path. > >>> >>> 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. > > Yeah but locking and locking 4 times when we can do it just ones is > quite waste. Please consider my suggestion above or tell what is wrong > with it. > > Argillander > If I've understood correctly, you want to lock once in start of function ntfs_save_wsl_perm and unlock at the end of it. It takes care of locks for those 4 calls to ntfs_set_ea. But there are still other calls to ntfs_set_ea, that aren't protected in this case: function ntfs_set_acl_ex (line 603 file fs/ntfs3/xattr.c) err = ntfs_set_ea(inode, name, name_len, value, size, flags, locked); This function called there: - function ntfs_set_acl (line 621 file fs/ntfs3/xattr.c) return ntfs_set_acl_ex(mnt_userns, inode, acl, type); - function ntfs_init_acl (line 701 file fs/ntfs3/xattr.c) err = ntfs_set_acl_ex(mnt_userns, inode, default_acl, - function ntfs_init_acl (line 712 file fs/ntfs3/xattr.c) err = ntfs_set_acl_ex(mnt_userns, inode, acl, So there are many entry points to ntfs_set_ea (and can be added more). Of course we can let int locked remain for these situations, but in my opinion it makes code a lot less readable (that was the reason to start looking into locking). I'm not sure, that winning some lock/unlocking in one specific scenario is worth it. >> >>>> if (err) >>>> goto out; >>>> } >>>> -- >>>> 2.33.0 >>>> >>>>