On 8/15/2014 22:33, Kinglong Mee wrote:
> On 8/15/2014 19:14, Jeff Layton wrote:
>> On Fri, 15 Aug 2014 08:07:12 +0800
>> Kinglong Mee <kinglongmee@xxxxxxxxx> wrote:
>>
>>> Commit d5b9026a67 ([PATCH] knfsd: locks: flag NFSv4-owned locks) using
>>> fl_lmops field in file_lock for checking nfsd4 lockowner.
>>>
>>> But, commit 1a747ee0cc (locks: don't call ->copy_lock methods on return
>>> of conflicting locks) causes the fl_lmops of conflock always be NULL.
>>>
>>> Also, commit 0996905f93 (lockd: posix_test_lock() should not call
>>> locks_copy_lock()) caused the fl_lmops of conflock always be NULL too.
>>>
>>> Make sure copy the private information by fl_copy_lock() in struct
>>> file_lock_operations, merge __locks_copy_lock() to fl_copy_lock().
>>>
>>> v3: Update based on Joe and Jeff's patch.
>>>
>>> Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
>>> ---
>>> fs/locks.c | 24 +++++++-----------------
>>> include/linux/fs.h | 6 ------
>>> 2 files changed, 7 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/fs/locks.c b/fs/locks.c
>>> index cb66fb0..fe52abb 100644
>>> --- a/fs/locks.c
>>> +++ b/fs/locks.c
>>> @@ -281,33 +281,23 @@ static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
>>> /*
>>> * Initialize a new lock from an existing file_lock structure.
>>> */
>>> -void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
>>> +void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
>>> {
>>> + /* "new" must be a freshly-initialized lock */
>>> + WARN_ON_ONCE(new->fl_ops);
>>> +
>>> new->fl_owner = fl->fl_owner;
>>> new->fl_pid = fl->fl_pid;
>>> - new->fl_file = NULL;
>>> + new->fl_file = fl->fl_file;
>>> new->fl_flags = fl->fl_flags;
>>> new->fl_type = fl->fl_type;
>>> new->fl_start = fl->fl_start;
>>> new->fl_end = fl->fl_end;
>>> new->fl_ops = NULL;
>>> new->fl_lmops = NULL;
>>> -}
>>> -EXPORT_SYMBOL(__locks_copy_lock);
>>> -
>>> -void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
>>> -{
>>> - /* "new" must be a freshly-initialized lock */
>>> - WARN_ON_ONCE(new->fl_ops);
>>> -
>>> - __locks_copy_lock(new, fl);
>>> - new->fl_file = fl->fl_file;
>>> - new->fl_ops = fl->fl_ops;
>>> - new->fl_lmops = fl->fl_lmops;
>>>
>>> locks_copy_private(new, fl);
>>> }
>>> -
>>> EXPORT_SYMBOL(locks_copy_lock);
>>>
>>> static inline int flock_translate_cmd(int cmd) {
>>> @@ -735,7 +725,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
>>> break;
>>> }
>>> if (cfl) {
>>> - __locks_copy_lock(fl, cfl);
>>> + locks_copy_lock(fl, cfl);
>>> if (cfl->fl_nspid)
>>> fl->fl_pid = pid_vnr(cfl->fl_nspid);
>>> } else
>>> @@ -941,7 +931,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
>>> if (!posix_locks_conflict(request, fl))
>>> continue;
>>> if (conflock)
>>> - __locks_copy_lock(conflock, fl);
>>> + locks_copy_lock(conflock, fl);
>>> error = -EAGAIN;
>>> if (!(request->fl_flags & FL_SLEEP))
>>> goto out;
>>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>>> index 908af4f..a383a30 100644
>>> --- a/include/linux/fs.h
>>> +++ b/include/linux/fs.h
>>> @@ -966,7 +966,6 @@ void locks_free_lock(struct file_lock *fl);
>>> extern void locks_init_lock(struct file_lock *);
>>> extern struct file_lock * locks_alloc_lock(void);
>>> extern void locks_copy_lock(struct file_lock *, struct file_lock *);
>>> -extern void __locks_copy_lock(struct file_lock *, const struct file_lock *);
>>> extern void locks_remove_posix(struct file *, fl_owner_t);
>>> extern void locks_remove_file(struct file *);
>>> extern void locks_release_private(struct file_lock *);
>>> @@ -1026,11 +1025,6 @@ static inline void locks_init_lock(struct file_lock *fl)
>>> return;
>>> }
>>>
>>> -static inline void __locks_copy_lock(struct file_lock *new, struct file_lock *fl)
>>> -{
>>> - return;
>>> -}
>>> -
>>> static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
>>> {
>>> return;
>>
>> I'm not sure this is really what you want to do. Calling fl_copy_lock
>> for a conflock looks relatively harmless for nfs and nlm. AFS though
>> seems to add the lock to a list associated with the inode. That seems a
>> little suspicious for a conflock and could be problematic. It may be
>> best to avoid dealing with fl_ops for a conflock.
>>
>> Also in the case of fcntl_getlk, the struct file_lock lives on the
>> stack, and locks_release_private is never called on it. You'll need to
>> audit all of the current callers of __locks_copy_lock to ensure that
>> any resources you end up taking references on when copying the conflock
>> are eventually released.
>
> Sorry for my no further think about it.
> I will check that again next day.
I think we should not change the logical of coping lock,
leave fl_ops and fl_lmops as private data as right now.
I have plan to,
1. move fl_owner assign from __locks_copy_lock() to locks_copy_private(),
I think it should be a private data, am I right?
2. call locks_copy_private() coping private data specifically.
a. add an argument for posix_test_lock() and __posix_lock_file() and etc,
to point whether coping private data.
b. hack the conflock's fl_flags to do the same thing as a,
adds FL_NEED_PRIV fl_flags only valid for conflock.
I don't think 2.a is a nice resolve, because it changes the interface
and many caller don't care the private data (I think contains fl_owner)
for conflock except nfsd.
So, I'd like *2.b*. A draft is appended as following,
thanks,
Kinglong Mee
------------------snip--------------------------
diff --git a/fs/locks.c b/fs/locks.c
index be1858e..5f0349d 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -282,6 +282,8 @@ static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
if (fl->fl_lmops) {
if (fl->fl_lmops->lm_copy_owner)
fl->fl_lmops->lm_copy_owner(new, fl);
+ else
+ new->fl_owner = fl->fl_owner;
new->fl_lmops = fl->fl_lmops;
}
}
@@ -291,7 +293,7 @@ static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
*/
void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
{
- new->fl_owner = fl->fl_owner;
+ new->fl_owner = NULL;
new->fl_pid = fl->fl_pid;
new->fl_file = NULL;
new->fl_flags = fl->fl_flags;
@@ -734,6 +736,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
{
struct file_lock *cfl;
struct inode *inode = file_inode(filp);
+ bool need_priv = !!(fl->fl_flags & FL_NEED_PRIV);
spin_lock(&inode->i_lock);
for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
@@ -746,6 +749,8 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
__locks_copy_lock(fl, cfl);
if (cfl->fl_nspid)
fl->fl_pid = pid_vnr(cfl->fl_nspid);
+ if (need_priv)
+ locks_copy_private(fl, cfl);
} else
fl->fl_type = F_UNLCK;
spin_unlock(&inode->i_lock);
@@ -919,7 +924,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
struct file_lock *right = NULL;
struct file_lock **before;
int error;
- bool added = false;
+ bool added = false, need_priv = false;
LIST_HEAD(dispose);
/*
@@ -948,8 +953,12 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
continue;
if (!posix_locks_conflict(request, fl))
continue;
- if (conflock)
+ if (conflock) {
+ need_priv = !!(conflock->fl_flags & FL_NEED_PRIV);
__locks_copy_lock(conflock, fl);
+ if (need_priv)
+ locks_copy_private(conflock, fl);
+ }
error = -EAGAIN;
if (!(request->fl_flags & FL_SLEEP))
goto out;
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 5076497..3db43f9 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5275,6 +5275,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
goto out;
}
+ conflock->fl_flags = FL_NEED_PRIV;
err = vfs_lock_file(filp, F_SETLK, file_lock, conflock);
switch (-err) {
case 0: /* success! */
@@ -5396,7 +5397,7 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
if (lo)
file_lock->fl_owner = (fl_owner_t)lo;
file_lock->fl_pid = current->tgid;
- file_lock->fl_flags = FL_POSIX;
+ file_lock->fl_flags = FL_POSIX | FL_NEED_PRIV;
file_lock->fl_start = lockt->lt_offset;
file_lock->fl_end = last_byte_offset(lockt->lt_offset, lockt->lt_length);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 56f2acd..f257d0d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -844,6 +844,7 @@ static inline struct file *get_file(struct file *f)
#define FL_DOWNGRADE_PENDING 256 /* Lease is being downgraded */
#define FL_UNLOCK_PENDING 512 /* Lease is being broken */
#define FL_OFDLCK 1024 /* lock is "owned" by struct file */
+#define FL_NEED_PRIV 2048 /* Need copy private data from conflock */
/*
* Special return value from posix_lock_file() and vfs_lock_file() for
--
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