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Message-ID: <20210927191005.zcebctlxfsqutgkh@kari-VirtualBox>
Date: Mon, 27 Sep 2021 22:10:05 +0300
From: Kari Argillander <kari.argillander@...il.com>
To: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
Cc: ntfs3@...ts.linux.dev, linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 2/3] fs/ntfs3: Remove locked argument in ntfs_set_ea
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 <sha>
> >
> > Have some comments below also.
> >
> >>
> >> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@...agon-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)
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 (err)
> >> goto out;
> >> }
> >> --
> >> 2.33.0
> >>
> >>
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