On Mon, 10 Mar 2014, Yan, Zheng wrote:
> flock and posix lock should use fl->fl_file instead of process ID
> as owner identifier. (posix lock uses fl->fl_owner, fl->fl_owner
> is usually equal to fl->fl_file in most cases). The process ID of
> who holds the lock is just for F_GETLK fcntl(2).
>
> The fix is rename the 'pid' fields of struct ceph_mds_request_args
> and struct ceph_filelock to 'owner', rename 'pid_namespace' fields
> to 'pid'. Assign fl->fl_file to the 'owner' field of lock messages.
>
> The MDS counterpart of this patch modifies the flock code to not
> take the 'pid_namespace' into consideration when checking conflict
> locks.
If I'm reading this right, it means the pid is purely informational now.
and 'owner' is a raw pointer from the client? That's unique, clearly, but
I suspect its a bad idea to share kernel pointers with any remote system?
Since this essentially boils down to a unique identifier for the thread
group, I wonder if we should opt for a different unique identifier for
that.
sage
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> ---
> fs/ceph/locks.c | 44 ++++++++++++++++++++++++--------------------
> include/linux/ceph/ceph_fs.h | 4 ++--
> 2 files changed, 26 insertions(+), 22 deletions(-)
>
> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
> index f91a569a..4857007 100644
> --- a/fs/ceph/locks.c
> +++ b/fs/ceph/locks.c
> @@ -14,9 +14,9 @@ static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
> int cmd, u8 wait, struct file_lock *fl)
> {
> struct inode *inode = file_inode(file);
> - struct ceph_mds_client *mdsc =
> - ceph_sb_to_client(inode->i_sb)->mdsc;
> + struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
> struct ceph_mds_request *req;
> + void *owner;
> int err;
> u64 length = 0;
>
> @@ -32,25 +32,28 @@ static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
> else
> length = fl->fl_end - fl->fl_start + 1;
>
> - dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
> - "length: %llu, wait: %d, type: %d", (int)lock_type,
> - (int)operation, (u64)fl->fl_pid, fl->fl_start,
> - length, wait, fl->fl_type);
> + if (lock_type == CEPH_LOCK_FCNTL)
> + owner = fl->fl_owner;
> + else
> + owner = fl->fl_file;
> +
> + dout("ceph_lock_message: rule: %d, op: %d, owner: %p, pid: %llu, "
> + "start: %llu, length: %llu, wait: %d, type: %d", (int)lock_type,
> + (int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length,
> + wait, fl->fl_type);
>
> req->r_args.filelock_change.rule = lock_type;
> req->r_args.filelock_change.type = cmd;
> + req->r_args.filelock_change.owner =
> + cpu_to_le64((u64)(unsigned long)owner);
> req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);
> - /* This should be adjusted, but I'm not sure if
> - namespaces actually get id numbers*/
> - req->r_args.filelock_change.pid_namespace =
> - cpu_to_le64((u64)(unsigned long)fl->fl_nspid);
> req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
> req->r_args.filelock_change.length = cpu_to_le64(length);
> req->r_args.filelock_change.wait = wait;
>
> err = ceph_mdsc_do_request(mdsc, inode, req);
>
> - if ( operation == CEPH_MDS_OP_GETFILELOCK){
> + if (operation == CEPH_MDS_OP_GETFILELOCK) {
> fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid);
> if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
> fl->fl_type = F_RDLCK;
> @@ -93,8 +96,7 @@ int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
> if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
> return -ENOLCK;
>
> - fl->fl_nspid = get_pid(task_tgid(current));
> - dout("ceph_lock, fl_pid:%d", fl->fl_pid);
> + dout("ceph_lock, fl_owner: %p", fl->fl_owner);
>
> /* set wait bit as appropriate, then make command as Ceph expects it*/
> if (IS_GETLK(cmd))
> @@ -111,7 +113,7 @@ int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
>
> err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
> if (!err) {
> - if ( op != CEPH_MDS_OP_GETFILELOCK ){
> + if (op != CEPH_MDS_OP_GETFILELOCK) {
> dout("mds locked, locking locally");
> err = posix_lock_file(file, fl, NULL);
> if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
> @@ -145,8 +147,7 @@ int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
> if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
> return -ENOLCK;
>
> - fl->fl_nspid = get_pid(task_tgid(current));
> - dout("ceph_flock, fl_pid:%d", fl->fl_pid);
> + dout("ceph_flock, fl_file: %p", fl->fl_file);
>
> if (IS_SETLKW(cmd))
> wait = 1;
> @@ -289,13 +290,16 @@ int lock_to_ceph_filelock(struct file_lock *lock,
> struct ceph_filelock *cephlock)
> {
> int err = 0;
> -
> cephlock->start = cpu_to_le64(lock->fl_start);
> cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
> cephlock->client = cpu_to_le64(0);
> - cephlock->pid = cpu_to_le64(lock->fl_pid);
> - cephlock->pid_namespace =
> - cpu_to_le64((u64)(unsigned long)lock->fl_nspid);
> + cephlock->pid = cpu_to_le64((u64)lock->fl_pid);
> + if (lock->fl_flags & FL_POSIX)
> + cephlock->owner =
> + cpu_to_le64((u64)(unsigned long)lock->fl_owner);
> + else
> + cephlock->owner =
> + cpu_to_le64((u64)(unsigned long)lock->fl_file);
>
> switch (lock->fl_type) {
> case F_RDLCK:
> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> index 35f345f..5f6db18 100644
> --- a/include/linux/ceph/ceph_fs.h
> +++ b/include/linux/ceph/ceph_fs.h
> @@ -421,8 +421,8 @@ union ceph_mds_request_args {
> struct {
> __u8 rule; /* currently fcntl or flock */
> __u8 type; /* shared, exclusive, remove*/
> + __le64 owner; /* owner of the lock */
> __le64 pid; /* process id requesting the lock */
> - __le64 pid_namespace;
> __le64 start; /* initial location to lock */
> __le64 length; /* num bytes to lock from start */
> __u8 wait; /* will caller wait for lock to become available? */
> @@ -533,8 +533,8 @@ struct ceph_filelock {
> __le64 start;/* file offset to start lock at */
> __le64 length; /* num bytes to lock; 0 for all following start */
> __le64 client; /* which client holds the lock */
> + __le64 owner; /* owner the lock */
> __le64 pid; /* process id holding the lock on the client */
> - __le64 pid_namespace;
> __u8 type; /* shared lock, exclusive lock, or unlock */
> } __attribute__ ((packed));
>
> --
> 1.8.5.3
>
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