On Tue, 2017-09-12 at 10:53 +0800, Yan, Zheng wrote:
> file locks are tracked by inode's auth mds. releasing auth caps
> is equivalent to releasing all file locks.
>
> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> ---
> fs/ceph/inode.c | 1 +
> fs/ceph/locks.c | 62 ++++++++++++++++++++++++++++++++++++++++++++--------
> fs/ceph/mds_client.c | 2 ++
> fs/ceph/super.h | 1 +
> 4 files changed, 57 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 373dab5173ca..c70b26d2bf8a 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -492,6 +492,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
> ci->i_wb_ref = 0;
> ci->i_wrbuffer_ref = 0;
> ci->i_wrbuffer_ref_head = 0;
> + atomic_set(&ci->i_filelock_ref, 0);
> ci->i_shared_gen = 0;
> ci->i_rdcache_gen = 0;
> ci->i_rdcache_revoking = 0;
> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
> index 64ae74472046..69f731e75302 100644
> --- a/fs/ceph/locks.c
> +++ b/fs/ceph/locks.c
> @@ -29,19 +29,46 @@ void __init ceph_flock_init(void)
> get_random_bytes(&lock_secret, sizeof(lock_secret));
> }
>
> +static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
> +{
> + struct inode *inode = file_inode(src->fl_file);
> + atomic_inc(&ceph_inode(inode)->i_filelock_ref);
> +}
> +
> +static void ceph_fl_release_lock(struct file_lock *fl)
> +{
> + struct inode *inode = file_inode(fl->fl_file);
> + atomic_dec(&ceph_inode(inode)->i_filelock_ref);
> +}
> +
> +static const struct file_lock_operations ceph_fl_lock_ops = {
> + .fl_copy_lock = ceph_fl_copy_lock,
> + .fl_release_private = ceph_fl_release_lock,
> +};
> +
> /**
> * Implement fcntl and flock locking functions.
> */
> -static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
> +static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode,
> 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_request *req;
> int err;
> u64 length = 0;
> u64 owner;
>
> + if (operation == CEPH_MDS_OP_SETFILELOCK) {
> + /*
> + * increasing i_filelock_ref closes race window between
> + * handling request reply and adding file_lock struct to
> + * inode. Otherwise, i_auth_cap may get trimmed in the
> + * window. Caller function will decrease the counter.
> + */
> + fl->fl_ops = &ceph_fl_lock_ops;
> + atomic_inc(&ceph_inode(inode)->i_filelock_ref);
> + }
> +
> if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK)
> wait = 0;
>
> @@ -179,10 +206,11 @@ static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
> */
> int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
> {
> - u8 lock_cmd;
> + struct inode *inode = file_inode(file);
> int err;
> - u8 wait = 0;
> u16 op = CEPH_MDS_OP_SETFILELOCK;
> + u8 lock_cmd;
> + u8 wait = 0;
>
> if (!(fl->fl_flags & FL_POSIX))
> return -ENOLCK;
> @@ -198,6 +226,17 @@ int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
> else if (IS_SETLKW(cmd))
> wait = 1;
>
> + if (op == CEPH_MDS_OP_SETFILELOCK) {
> + /*
> + * increasing i_filelock_ref closes race window between
> + * handling request reply and adding file_lock struct to
> + * inode. Otherwise, i_auth_cap may get trimmed in the
> + * window. Caller function will decrease the counter.
> + */
> + fl->fl_ops = &ceph_fl_lock_ops;
> + atomic_inc(&ceph_inode(inode)->i_filelock_ref);
> + }
> +
> if (F_RDLCK == fl->fl_type)
> lock_cmd = CEPH_LOCK_SHARED;
> else if (F_WRLCK == fl->fl_type)
> @@ -205,7 +244,7 @@ int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
> else
> lock_cmd = CEPH_LOCK_UNLOCK;
>
> - err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
> + err = ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, lock_cmd, wait, fl);
> if (!err) {
> if (op != CEPH_MDS_OP_GETFILELOCK) {
> dout("mds locked, locking locally");
> @@ -214,7 +253,7 @@ int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
> /* undo! This should only happen if
> * the kernel detects local
> * deadlock. */
> - ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
> + ceph_lock_message(CEPH_LOCK_FCNTL, op, inode,
> CEPH_LOCK_UNLOCK, 0, fl);
> dout("got %d on posix_lock_file, undid lock",
> err);
> @@ -226,8 +265,9 @@ int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
>
> int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
> {
> - u8 lock_cmd;
> + struct inode *inode = file_inode(file);
> int err;
> + u8 lock_cmd;
> u8 wait = 0;
>
> if (!(fl->fl_flags & FL_FLOCK))
> @@ -238,6 +278,10 @@ int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
>
> dout("ceph_flock, fl_file: %p", fl->fl_file);
>
> + /* see comment in ceph_lock */
> + fl->fl_ops = &ceph_fl_lock_ops;
> + atomic_inc(&ceph_inode(inode)->i_filelock_ref);
> +
> if (IS_SETLKW(cmd))
> wait = 1;
>
> @@ -249,13 +293,13 @@ int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
> lock_cmd = CEPH_LOCK_UNLOCK;
>
> err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
> - file, lock_cmd, wait, fl);
> + inode, lock_cmd, wait, fl);
> if (!err) {
> err = locks_lock_file_wait(file, fl);
> if (err) {
> ceph_lock_message(CEPH_LOCK_FLOCK,
> CEPH_MDS_OP_SETFILELOCK,
> - file, CEPH_LOCK_UNLOCK, 0, fl);
> + inode, CEPH_LOCK_UNLOCK, 0, fl);
> dout("got %d on locks_lock_file_wait, undid lock", err);
> }
> }
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 9dd6b836ac9e..6146af4ed03c 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -1461,6 +1461,8 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
> goto out;
> if ((used | wanted) & CEPH_CAP_ANY_WR)
> goto out;
> + if (atomic_read(&ci->i_filelock_ref) > 0)
> + goto out;
Is there a potential race here? Could i_filelock_ref do a 0->1
transition just after you check it?
> }
> /* The inode has cached pages, but it's no longer used.
> * we can safely drop it */
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 279a2f401cf5..9e0de8264257 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -351,6 +351,7 @@ struct ceph_inode_info {
> int i_pin_ref;
> int i_rd_ref, i_rdcache_ref, i_wr_ref, i_wb_ref;
> int i_wrbuffer_ref, i_wrbuffer_ref_head;
> + atomic_t i_filelock_ref;
> u32 i_shared_gen; /* increment each time we get FILE_SHARED */
> u32 i_rdcache_gen; /* incremented each time we get FILE_CACHE. */
> u32 i_rdcache_revoking; /* RDCACHE gen to async invalidate, if any */
--
Jeff Layton <jlayton@xxxxxxxxxx>
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