Reviewed-by: Sage Weil <sage@xxxxxxxxxxx>
On Tue, 11 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, but it also can be a customized
> value). 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.
> We also set the most significant bit of the 'owner' field. MDS can
> use that bit to distinguish between old and new clients.
>
> The MDS counterpart of this patch modifies the flock code to not
> take the 'pid_namespace' into consideration when checking conflict
> locks.
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> ---
> fs/ceph/locks.c | 61 +++++++++++++++++++++++++++++---------------
> fs/ceph/super.c | 1 +
> fs/ceph/super.h | 1 +
> include/linux/ceph/ceph_fs.h | 4 +--
> 4 files changed, 45 insertions(+), 22 deletions(-)
>
> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
> index f91a569a..8dbae5d 100644
> --- a/fs/ceph/locks.c
> +++ b/fs/ceph/locks.c
> @@ -2,11 +2,31 @@
>
> #include <linux/file.h>
> #include <linux/namei.h>
> +#include <linux/random.h>
>
> #include "super.h"
> #include "mds_client.h"
> #include <linux/ceph/pagelist.h>
>
> +static u64 lock_secret;
> +
> +static inline u64 secure_addr(void *addr)
> +{
> + u64 v = (lock_secret ^ (u64)(unsigned long)addr);
> + /*
> + * Set the most significant bit, so that MDS knows the 'owner'
> + * is sufficient to identify the owner of lock. (old code uses
> + * both 'owner' and 'pid')
> + */
> + v |= (1ULL << 63);
> + return v;
> +}
> +
> +void __init ceph_flock_init(void)
> +{
> + get_random_bytes(&lock_secret, sizeof(lock_secret));
> +}
> +
> /**
> * Implement fcntl and flock locking functions.
> */
> @@ -14,11 +34,11 @@ 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;
> int err;
> u64 length = 0;
> + u64 owner;
>
> req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
> if (IS_ERR(req))
> @@ -32,25 +52,27 @@ 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 = secure_addr(fl->fl_owner);
> + else
> + owner = secure_addr(fl->fl_file);
> +
> + dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, 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(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 +115,7 @@ 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 +132,7 @@ 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 +166,7 @@ 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 +309,14 @@ 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(secure_addr(lock->fl_owner));
> + else
> + cephlock->owner = cpu_to_le64(secure_addr(lock->fl_file));
>
> switch (lock->fl_type) {
> case F_RDLCK:
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index 10a4ccb..06150fd 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -1026,6 +1026,7 @@ static int __init init_ceph(void)
> if (ret)
> goto out;
>
> + ceph_flock_init();
> ceph_xattr_init();
> ret = register_filesystem(&ceph_fs_type);
> if (ret)
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 70bb183..7866cd0 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -871,6 +871,7 @@ extern long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
> extern const struct export_operations ceph_export_ops;
>
> /* locks.c */
> +extern __init void ceph_flock_init(void);
> extern int ceph_lock(struct file *file, int cmd, struct file_lock *fl);
> extern int ceph_flock(struct file *file, int cmd, struct file_lock *fl);
> extern void ceph_count_locks(struct inode *inode, int *p_num, int *f_num);
> 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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