[PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[Amir Goldstein]

nfsd and lockd call vfs_lock_file() to lock/unlock the inode
returned by locks_inode(file).

Many places in nfsd/lockd code use the inode returned by
file_inode(file) for lock manipulation. With Overlayfs, file_inode()
(the underlying inode) is not the same object as locks_inode() (the
overlay inode). This can result in "Leaked POSIX lock" messages
and eventually to a kernel crash as reported by Eddie Horng:
https://marc.info/?l=linux-unionfs&m=153086643202072&w=2

Fix all the call sites in nfsd/lockd that should use locks_inode().
This is a correctness bug that manifested when overlayfs gained
NFS export support in v4.16.

Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Hi Bruce,

For the purpose of locks, nfsd/lockd should look at locks_inode()
just like vfs lock functions.

Hopefully, Miklos's work on stacked overlayfs file operations will
be merged soon and locks_inode() will become the same as file_inode(),
but we will still need this fix for stable kernels v4.16 through v4.18.

Beyond testing by Eddie, I also verified no regressions when running
nfstest with exported overlayfs.

Thanks,
Amir.

 fs/lockd/clntlock.c         |  2 +-
 fs/lockd/clntproc.c         |  2 +-
 fs/lockd/svclock.c          | 16 ++++++++--------
 fs/lockd/svcsubs.c          |  4 ++--
 fs/nfsd/nfs4state.c         |  2 +-
 include/linux/lockd/lockd.h |  4 ++--
 6 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 96c1d14c18f1..c2a128678e6e 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -187,7 +187,7 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
 			continue;
 		if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
 			continue;
-		if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0)
+		if (nfs_compare_fh(NFS_FH(locks_inode(fl_blocked->fl_file)), fh) != 0)
 			continue;
 		/* Alright, we found a lock. Set the return status
 		 * and wake up the caller
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index a2c0dfc6fdc0..d20b92f271c2 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -128,7 +128,7 @@ static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 	char *nodename = req->a_host->h_rpcclnt->cl_nodename;
 
 	nlmclnt_next_cookie(&argp->cookie);
-	memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
+	memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh));
 	lock->caller  = nodename;
 	lock->oh.data = req->a_owner;
 	lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 3701bccab478..74330daeab71 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -405,8 +405,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 	__be32			ret;
 
 	dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
-				file_inode(file->f_file)->i_sb->s_id,
-				file_inode(file->f_file)->i_ino,
+				locks_inode(file->f_file)->i_sb->s_id,
+				locks_inode(file->f_file)->i_ino,
 				lock->fl.fl_type, lock->fl.fl_pid,
 				(long long)lock->fl.fl_start,
 				(long long)lock->fl.fl_end,
@@ -511,8 +511,8 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
 	__be32			ret;
 
 	dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
-				file_inode(file->f_file)->i_sb->s_id,
-				file_inode(file->f_file)->i_ino,
+				locks_inode(file->f_file)->i_sb->s_id,
+				locks_inode(file->f_file)->i_ino,
 				lock->fl.fl_type,
 				(long long)lock->fl.fl_start,
 				(long long)lock->fl.fl_end);
@@ -566,8 +566,8 @@ nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
 	int	error;
 
 	dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
-				file_inode(file->f_file)->i_sb->s_id,
-				file_inode(file->f_file)->i_ino,
+				locks_inode(file->f_file)->i_sb->s_id,
+				locks_inode(file->f_file)->i_ino,
 				lock->fl.fl_pid,
 				(long long)lock->fl.fl_start,
 				(long long)lock->fl.fl_end);
@@ -595,8 +595,8 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l
 	int status = 0;
 
 	dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
-				file_inode(file->f_file)->i_sb->s_id,
-				file_inode(file->f_file)->i_ino,
+				locks_inode(file->f_file)->i_sb->s_id,
+				locks_inode(file->f_file)->i_ino,
 				lock->fl.fl_pid,
 				(long long)lock->fl.fl_start,
 				(long long)lock->fl.fl_end);
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index 4ec3d6e03e76..899360ba3b84 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -44,7 +44,7 @@ static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
 
 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
 {
-	struct inode *inode = file_inode(file->f_file);
+	struct inode *inode = locks_inode(file->f_file);
 
 	dprintk("lockd: %s %s/%ld\n",
 		msg, inode->i_sb->s_id, inode->i_ino);
@@ -414,7 +414,7 @@ nlmsvc_match_sb(void *datap, struct nlm_file *file)
 {
 	struct super_block *sb = datap;
 
-	return sb == file_inode(file->f_file)->i_sb;
+	return sb == locks_inode(file->f_file)->i_sb;
 }
 
 /**
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 857141446d6b..4a17fad93411 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6293,7 +6293,7 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
 		return status;
 	}
 
-	inode = file_inode(filp);
+	inode = locks_inode(filp);
 	flctx = inode->i_flctx;
 
 	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 4fd95dbeb52f..b065ef406770 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -299,7 +299,7 @@ int           nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr);
 
 static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
 {
-	return file_inode(file->f_file);
+	return locks_inode(file->f_file);
 }
 
 static inline int __nlm_privileged_request4(const struct sockaddr *sap)
@@ -359,7 +359,7 @@ static inline int nlm_privileged_requester(const struct svc_rqst *rqstp)
 static inline int nlm_compare_locks(const struct file_lock *fl1,
 				    const struct file_lock *fl2)
 {
-	return file_inode(fl1->fl_file) == file_inode(fl2->fl_file)
+	return locks_inode(fl1->fl_file) == locks_inode(fl2->fl_file)
 	     && fl1->fl_pid   == fl2->fl_pid
 	     && fl1->fl_owner == fl2->fl_owner
 	     && fl1->fl_start == fl2->fl_start
-- 
2.7.4

Re: [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[Jeff Layton]

On Fri, 2018-07-13 at 17:22 +0300, Amir Goldstein wrote:
> nfsd and lockd call vfs_lock_file() to lock/unlock the inode
> returned by locks_inode(file).
> 
> Many places in nfsd/lockd code use the inode returned by
> file_inode(file) for lock manipulation. With Overlayfs, file_inode()
> (the underlying inode) is not the same object as locks_inode() (the
> overlay inode). This can result in "Leaked POSIX lock" messages
> and eventually to a kernel crash as reported by Eddie Horng:
> https://marc.info/?l=linux-unionfs&m=153086643202072&w=2
> 
> Fix all the call sites in nfsd/lockd that should use locks_inode().
> This is a correctness bug that manifested when overlayfs gained
> NFS export support in v4.16.
> 
> Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
> Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
> Cc: Jeff Layton <jlayton@kernel.org>
> Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
> 
> Hi Bruce,
> 
> For the purpose of locks, nfsd/lockd should look at locks_inode()
> just like vfs lock functions.
> 
> Hopefully, Miklos's work on stacked overlayfs file operations will
> be merged soon and locks_inode() will become the same as file_inode(),
> but we will still need this fix for stable kernels v4.16 through v4.18.
> 
> Beyond testing by Eddie, I also verified no regressions when running
> nfstest with exported overlayfs.
> 
> Thanks,
> Amir.
> 
>  fs/lockd/clntlock.c         |  2 +-
>  fs/lockd/clntproc.c         |  2 +-
>  fs/lockd/svclock.c          | 16 ++++++++--------
>  fs/lockd/svcsubs.c          |  4 ++--
>  fs/nfsd/nfs4state.c         |  2 +-
>  include/linux/lockd/lockd.h |  4 ++--
>  6 files changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
> index 96c1d14c18f1..c2a128678e6e 100644
> --- a/fs/lockd/clntlock.c
> +++ b/fs/lockd/clntlock.c
> @@ -187,7 +187,7 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
>  			continue;
>  		if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
>  			continue;
> -		if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0)
> +		if (nfs_compare_fh(NFS_FH(locks_inode(fl_blocked->fl_file)), fh) != 0)
>  			continue;
>  		/* Alright, we found a lock. Set the return status
>  		 * and wake up the caller
> diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
> index a2c0dfc6fdc0..d20b92f271c2 100644
> --- a/fs/lockd/clntproc.c
> +++ b/fs/lockd/clntproc.c
> @@ -128,7 +128,7 @@ static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
>  	char *nodename = req->a_host->h_rpcclnt->cl_nodename;
>  
>  	nlmclnt_next_cookie(&argp->cookie);
> -	memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
> +	memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh));
>  	lock->caller  = nodename;
>  	lock->oh.data = req->a_owner;
>  	lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
> diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
> index 3701bccab478..74330daeab71 100644
> --- a/fs/lockd/svclock.c
> +++ b/fs/lockd/svclock.c
> @@ -405,8 +405,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
>  	__be32			ret;
>  
>  	dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
> -				file_inode(file->f_file)->i_sb->s_id,
> -				file_inode(file->f_file)->i_ino,
> +				locks_inode(file->f_file)->i_sb->s_id,
> +				locks_inode(file->f_file)->i_ino,
>  				lock->fl.fl_type, lock->fl.fl_pid,
>  				(long long)lock->fl.fl_start,
>  				(long long)lock->fl.fl_end,
> @@ -511,8 +511,8 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
>  	__be32			ret;
>  
>  	dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
> -				file_inode(file->f_file)->i_sb->s_id,
> -				file_inode(file->f_file)->i_ino,
> +				locks_inode(file->f_file)->i_sb->s_id,
> +				locks_inode(file->f_file)->i_ino,
>  				lock->fl.fl_type,
>  				(long long)lock->fl.fl_start,
>  				(long long)lock->fl.fl_end);
> @@ -566,8 +566,8 @@ nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
>  	int	error;
>  
>  	dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
> -				file_inode(file->f_file)->i_sb->s_id,
> -				file_inode(file->f_file)->i_ino,
> +				locks_inode(file->f_file)->i_sb->s_id,
> +				locks_inode(file->f_file)->i_ino,
>  				lock->fl.fl_pid,
>  				(long long)lock->fl.fl_start,
>  				(long long)lock->fl.fl_end);
> @@ -595,8 +595,8 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l
>  	int status = 0;
>  
>  	dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
> -				file_inode(file->f_file)->i_sb->s_id,
> -				file_inode(file->f_file)->i_ino,
> +				locks_inode(file->f_file)->i_sb->s_id,
> +				locks_inode(file->f_file)->i_ino,
>  				lock->fl.fl_pid,
>  				(long long)lock->fl.fl_start,
>  				(long long)lock->fl.fl_end);
> diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
> index 4ec3d6e03e76..899360ba3b84 100644
> --- a/fs/lockd/svcsubs.c
> +++ b/fs/lockd/svcsubs.c
> @@ -44,7 +44,7 @@ static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
>  
>  static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
>  {
> -	struct inode *inode = file_inode(file->f_file);
> +	struct inode *inode = locks_inode(file->f_file);
>  
>  	dprintk("lockd: %s %s/%ld\n",
>  		msg, inode->i_sb->s_id, inode->i_ino);
> @@ -414,7 +414,7 @@ nlmsvc_match_sb(void *datap, struct nlm_file *file)
>  {
>  	struct super_block *sb = datap;
>  
> -	return sb == file_inode(file->f_file)->i_sb;
> +	return sb == locks_inode(file->f_file)->i_sb;
>  }
>  
>  /**
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 857141446d6b..4a17fad93411 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -6293,7 +6293,7 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
>  		return status;
>  	}
>  
> -	inode = file_inode(filp);
> +	inode = locks_inode(filp);
>  	flctx = inode->i_flctx;
>  
>  	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
> index 4fd95dbeb52f..b065ef406770 100644
> --- a/include/linux/lockd/lockd.h
> +++ b/include/linux/lockd/lockd.h
> @@ -299,7 +299,7 @@ int           nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr);
>  
>  static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
>  {
> -	return file_inode(file->f_file);
> +	return locks_inode(file->f_file);
>  }
>  

fwiw, I think the above delta turns out to be the real fix here, as that
affects nlm_file_inuse.
 
>  static inline int __nlm_privileged_request4(const struct sockaddr *sap)
> @@ -359,7 +359,7 @@ static inline int nlm_privileged_requester(const struct svc_rqst *rqstp)
>  static inline int nlm_compare_locks(const struct file_lock *fl1,
>  				    const struct file_lock *fl2)
>  {
> -	return file_inode(fl1->fl_file) == file_inode(fl2->fl_file)
> +	return locks_inode(fl1->fl_file) == locks_inode(fl2->fl_file)
>  	     && fl1->fl_pid   == fl2->fl_pid
>  	     && fl1->fl_owner == fl2->fl_owner
>  	     && fl1->fl_start == fl2->fl_start

I think this looks OK. I was a bit hesitant as I wasn't sure whether
this would change the filehandles presented by the nfsd, but I don't
think it will.

Reviewed-by: Jeff Layton <jlayton@kernel.org>

Re: [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[Amir Goldstein]

On Fri, Jul 13, 2018 at 6:40 PM, Jeff Layton <jlayton@kernel.org> wrote:
> On Fri, 2018-07-13 at 17:22 +0300, Amir Goldstein wrote:
>> nfsd and lockd call vfs_lock_file() to lock/unlock the inode
>> returned by locks_inode(file).
>>
>> Many places in nfsd/lockd code use the inode returned by
>> file_inode(file) for lock manipulation. With Overlayfs, file_inode()
>> (the underlying inode) is not the same object as locks_inode() (the
>> overlay inode). This can result in "Leaked POSIX lock" messages
>> and eventually to a kernel crash as reported by Eddie Horng:
>> https://marc.info/?l=linux-unionfs&m=153086643202072&w=2
>>
>> Fix all the call sites in nfsd/lockd that should use locks_inode().
>> This is a correctness bug that manifested when overlayfs gained
>> NFS export support in v4.16.
>>
>> Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
>> Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
>> Cc: Jeff Layton <jlayton@kernel.org>
>> Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
>> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
>> ---
>>
>> Hi Bruce,
>>
>> For the purpose of locks, nfsd/lockd should look at locks_inode()
>> just like vfs lock functions.
>>
>> Hopefully, Miklos's work on stacked overlayfs file operations will
>> be merged soon and locks_inode() will become the same as file_inode(),
>> but we will still need this fix for stable kernels v4.16 through v4.18.
>>
>> Beyond testing by Eddie, I also verified no regressions when running
>> nfstest with exported overlayfs.
>>
>> Thanks,
>> Amir.
>>
>>  fs/lockd/clntlock.c         |  2 +-
>>  fs/lockd/clntproc.c         |  2 +-
>>  fs/lockd/svclock.c          | 16 ++++++++--------
>>  fs/lockd/svcsubs.c          |  4 ++--
>>  fs/nfsd/nfs4state.c         |  2 +-
>>  include/linux/lockd/lockd.h |  4 ++--
>>  6 files changed, 15 insertions(+), 15 deletions(-)
>>
>> diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
>> index 96c1d14c18f1..c2a128678e6e 100644
>> --- a/fs/lockd/clntlock.c
>> +++ b/fs/lockd/clntlock.c
>> @@ -187,7 +187,7 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
>>                       continue;
>>               if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
>>                       continue;
>> -             if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0)
>> +             if (nfs_compare_fh(NFS_FH(locks_inode(fl_blocked->fl_file)), fh) != 0)
>>                       continue;
>>               /* Alright, we found a lock. Set the return status
>>                * and wake up the caller
>> diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
>> index a2c0dfc6fdc0..d20b92f271c2 100644
>> --- a/fs/lockd/clntproc.c
>> +++ b/fs/lockd/clntproc.c
>> @@ -128,7 +128,7 @@ static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
>>       char *nodename = req->a_host->h_rpcclnt->cl_nodename;
>>
>>       nlmclnt_next_cookie(&argp->cookie);
>> -     memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
>> +     memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh));
>>       lock->caller  = nodename;
>>       lock->oh.data = req->a_owner;
>>       lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
>> diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
>> index 3701bccab478..74330daeab71 100644
>> --- a/fs/lockd/svclock.c
>> +++ b/fs/lockd/svclock.c
>> @@ -405,8 +405,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
>>       __be32                  ret;
>>
>>       dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
>> -                             file_inode(file->f_file)->i_sb->s_id,
>> -                             file_inode(file->f_file)->i_ino,
>> +                             locks_inode(file->f_file)->i_sb->s_id,
>> +                             locks_inode(file->f_file)->i_ino,
>>                               lock->fl.fl_type, lock->fl.fl_pid,
>>                               (long long)lock->fl.fl_start,
>>                               (long long)lock->fl.fl_end,
>> @@ -511,8 +511,8 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
>>       __be32                  ret;
>>
>>       dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
>> -                             file_inode(file->f_file)->i_sb->s_id,
>> -                             file_inode(file->f_file)->i_ino,
>> +                             locks_inode(file->f_file)->i_sb->s_id,
>> +                             locks_inode(file->f_file)->i_ino,
>>                               lock->fl.fl_type,
>>                               (long long)lock->fl.fl_start,
>>                               (long long)lock->fl.fl_end);
>> @@ -566,8 +566,8 @@ nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
>>       int     error;
>>
>>       dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
>> -                             file_inode(file->f_file)->i_sb->s_id,
>> -                             file_inode(file->f_file)->i_ino,
>> +                             locks_inode(file->f_file)->i_sb->s_id,
>> +                             locks_inode(file->f_file)->i_ino,
>>                               lock->fl.fl_pid,
>>                               (long long)lock->fl.fl_start,
>>                               (long long)lock->fl.fl_end);
>> @@ -595,8 +595,8 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l
>>       int status = 0;
>>
>>       dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
>> -                             file_inode(file->f_file)->i_sb->s_id,
>> -                             file_inode(file->f_file)->i_ino,
>> +                             locks_inode(file->f_file)->i_sb->s_id,
>> +                             locks_inode(file->f_file)->i_ino,
>>                               lock->fl.fl_pid,
>>                               (long long)lock->fl.fl_start,
>>                               (long long)lock->fl.fl_end);
>> diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
>> index 4ec3d6e03e76..899360ba3b84 100644
>> --- a/fs/lockd/svcsubs.c
>> +++ b/fs/lockd/svcsubs.c
>> @@ -44,7 +44,7 @@ static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
>>
>>  static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
>>  {
>> -     struct inode *inode = file_inode(file->f_file);
>> +     struct inode *inode = locks_inode(file->f_file);
>>
>>       dprintk("lockd: %s %s/%ld\n",
>>               msg, inode->i_sb->s_id, inode->i_ino);
>> @@ -414,7 +414,7 @@ nlmsvc_match_sb(void *datap, struct nlm_file *file)
>>  {
>>       struct super_block *sb = datap;
>>
>> -     return sb == file_inode(file->f_file)->i_sb;
>> +     return sb == locks_inode(file->f_file)->i_sb;
>>  }
>>
>>  /**
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 857141446d6b..4a17fad93411 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -6293,7 +6293,7 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
>>               return status;
>>       }
>>
>> -     inode = file_inode(filp);
>> +     inode = locks_inode(filp);
>>       flctx = inode->i_flctx;
>>
>>       if (flctx && !list_empty_careful(&flctx->flc_posix)) {
>> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
>> index 4fd95dbeb52f..b065ef406770 100644
>> --- a/include/linux/lockd/lockd.h
>> +++ b/include/linux/lockd/lockd.h
>> @@ -299,7 +299,7 @@ int           nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr);
>>
>>  static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
>>  {
>> -     return file_inode(file->f_file);
>> +     return locks_inode(file->f_file);
>>  }
>>
>
> fwiw, I think the above delta turns out to be the real fix here, as that
> affects nlm_file_inuse.
>
>>  static inline int __nlm_privileged_request4(const struct sockaddr *sap)
>> @@ -359,7 +359,7 @@ static inline int nlm_privileged_requester(const struct svc_rqst *rqstp)
>>  static inline int nlm_compare_locks(const struct file_lock *fl1,
>>                                   const struct file_lock *fl2)
>>  {
>> -     return file_inode(fl1->fl_file) == file_inode(fl2->fl_file)
>> +     return locks_inode(fl1->fl_file) == locks_inode(fl2->fl_file)
>>            && fl1->fl_pid   == fl2->fl_pid
>>            && fl1->fl_owner == fl2->fl_owner
>>            && fl1->fl_start == fl2->fl_start
>
> I think this looks OK. I was a bit hesitant as I wasn't sure whether
> this would change the filehandles presented by the nfsd, but I don't
> think it will.
>

Well, if nfsd were to ask overlayfs to encode a file handle, nfsd would
need to pass in an overlay inode (a.k.a. locks_inode()) not an underlying
inode, so if anything, this patch reduces the chance of file handle
encoding bugs. In any case, we will all be better off when file_inode()
is an overlay inode.

> Reviewed-by: Jeff Layton <jlayton@kernel.org>

Thanks,
Amir.

Re: [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[Miklos Szeredi]

On Fri, Jul 13, 2018 at 6:05 PM, Amir Goldstein <amir73il@gmail.com> wrote:
> On Fri, Jul 13, 2018 at 6:40 PM, Jeff Layton <jlayton@kernel.org> wrote:
>> On Fri, 2018-07-13 at 17:22 +0300, Amir Goldstein wrote:
>>> nfsd and lockd call vfs_lock_file() to lock/unlock the inode
>>> returned by locks_inode(file).
>>>
>>> Many places in nfsd/lockd code use the inode returned by
>>> file_inode(file) for lock manipulation. With Overlayfs, file_inode()
>>> (the underlying inode) is not the same object as locks_inode() (the
>>> overlay inode). This can result in "Leaked POSIX lock" messages
>>> and eventually to a kernel crash as reported by Eddie Horng:
>>> https://marc.info/?l=linux-unionfs&m=153086643202072&w=2
>>>
>>> Fix all the call sites in nfsd/lockd that should use locks_inode().
>>> This is a correctness bug that manifested when overlayfs gained
>>> NFS export support in v4.16.
>>>
>>> Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
>>> Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
>>> Cc: Jeff Layton <jlayton@kernel.org>
>>> Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
>>> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
>>> ---
>>>
>>> Hi Bruce,
>>>
>>> For the purpose of locks, nfsd/lockd should look at locks_inode()
>>> just like vfs lock functions.
>>>
>>> Hopefully, Miklos's work on stacked overlayfs file operations will
>>> be merged soon and locks_inode() will become the same as file_inode(),
>>> but we will still need this fix for stable kernels v4.16 through v4.18.

Needs a Cc: stable@... tag then.

Should I take this patch (based on the fact that it only affects
overlayfs exports)?

Or will you take it, Bruce?

Thanks,
Miklos

>> Reviewed-by: Jeff Layton <jlayton@kernel.org>

Re: [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[Amir Goldstein]

On Tue, Jul 17, 2018 at 5:24 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Fri, Jul 13, 2018 at 6:05 PM, Amir Goldstein <amir73il@gmail.com> wrote:
>> On Fri, Jul 13, 2018 at 6:40 PM, Jeff Layton <jlayton@kernel.org> wrote:
>>> On Fri, 2018-07-13 at 17:22 +0300, Amir Goldstein wrote:
>>>> nfsd and lockd call vfs_lock_file() to lock/unlock the inode
>>>> returned by locks_inode(file).
>>>>
>>>> Many places in nfsd/lockd code use the inode returned by
>>>> file_inode(file) for lock manipulation. With Overlayfs, file_inode()
>>>> (the underlying inode) is not the same object as locks_inode() (the
>>>> overlay inode). This can result in "Leaked POSIX lock" messages
>>>> and eventually to a kernel crash as reported by Eddie Horng:
>>>> https://marc.info/?l=linux-unionfs&m=153086643202072&w=2
>>>>
>>>> Fix all the call sites in nfsd/lockd that should use locks_inode().
>>>> This is a correctness bug that manifested when overlayfs gained
>>>> NFS export support in v4.16.
>>>>
>>>> Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
>>>> Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
>>>> Cc: Jeff Layton <jlayton@kernel.org>
>>>> Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
>>>> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
>>>> ---
>>>>
>>>> Hi Bruce,
>>>>
>>>> For the purpose of locks, nfsd/lockd should look at locks_inode()
>>>> just like vfs lock functions.
>>>>
>>>> Hopefully, Miklos's work on stacked overlayfs file operations will
>>>> be merged soon and locks_inode() will become the same as file_inode(),
>>>> but we will still need this fix for stable kernels v4.16 through v4.18.
>
> Needs a Cc: stable@... tag then.
>
> Should I take this patch (based on the fact that it only affects
> overlayfs exports)?
>
> Or will you take it, Bruce?
>

Bruce? Jeff?

It's probably a good time for someone to put this patch in -next.

Should Miklos do it?

Thanks,
Amir.

Re: [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs

[J . Bruce Fields]

On Wed, Aug 01, 2018 at 09:18:24AM +0300, Amir Goldstein wrote:
> On Tue, Jul 17, 2018 at 5:24 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> > Needs a Cc: stable@... tag then.
> >
> > Should I take this patch (based on the fact that it only affects
> > overlayfs exports)?
> >
> > Or will you take it, Bruce?
> >
> 
> Bruce? Jeff?
> 
> It's probably a good time for someone to put this patch in -next.
> 
> Should Miklos do it?

I'm applying it, thanks for the reminder.  (Or I'd be OK with Miklos
taking it.)

--b.