locks: add a dedicated spinlock to protect i_flctx lists

We can now add a dedicated spinlock without expanding struct inode.
Change to using that to protect the various i_flctx lists.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>

fs/ceph/locks.c

@@ -255,12 +255,12 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
 
 	ctx = inode->i_flctx;
 	if (ctx) {
-		spin_lock(&inode->i_lock);
+		spin_lock(&ctx->flc_lock);
 		list_for_each_entry(lock, &ctx->flc_posix, fl_list)
 			++(*fcntl_count);
 		list_for_each_entry(lock, &ctx->flc_flock, fl_list)
 			++(*flock_count);
-		spin_unlock(&inode->i_lock);
+		spin_unlock(&ctx->flc_lock);
 	}
 	dout("counted %d flock locks and %d fcntl locks",
 	     *flock_count, *fcntl_count);
@@ -288,7 +288,7 @@ int ceph_encode_locks_to_buffer(struct inode *inode,
 	if (!ctx)
 		return 0;
 
-	spin_lock(&inode->i_lock);
+	spin_lock(&ctx->flc_lock);
 	list_for_each_entry(lock, &ctx->flc_flock, fl_list) {
 		++seen_fcntl;
 		if (seen_fcntl > num_fcntl_locks) {
@@ -312,7 +312,7 @@ int ceph_encode_locks_to_buffer(struct inode *inode,
 		++l;
 	}
 fail:
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&ctx->flc_lock);
 	return err;
 }
 

fs/cifs/file.c

@@ -1136,11 +1136,11 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
 	if (!flctx)
 		goto out;
 
-	spin_lock(&inode->i_lock);
+	spin_lock(&flctx->flc_lock);
 	list_for_each(el, &flctx->flc_posix) {
 		count++;
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&flctx->flc_lock);
 
 	INIT_LIST_HEAD(&locks_to_send);
 
@@ -1159,7 +1159,7 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
 	}
 
 	el = locks_to_send.next;
-	spin_lock(&inode->i_lock);
+	spin_lock(&flctx->flc_lock);
 	list_for_each_entry(flock, &flctx->flc_posix, fl_list) {
 		if (el == &locks_to_send) {
 			/*
@@ -1181,7 +1181,7 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
 		lck->type = type;
 		lck->offset = flock->fl_start;
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&flctx->flc_lock);
 
 	list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
 		int stored_rc;

fs/lockd/svcsubs.c

@@ -171,7 +171,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 		return 0;
 again:
 	file->f_locks = 0;
-	spin_lock(&inode->i_lock);
+	spin_lock(&flctx->flc_lock);
 	list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
 		if (fl->fl_lmops != &nlmsvc_lock_operations)
 			continue;
@@ -183,7 +183,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 		if (match(lockhost, host)) {
 			struct file_lock lock = *fl;
 
-			spin_unlock(&inode->i_lock);
+			spin_unlock(&flctx->flc_lock);
 			lock.fl_type  = F_UNLCK;
 			lock.fl_start = 0;
 			lock.fl_end   = OFFSET_MAX;
@@ -195,7 +195,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 			goto again;
 		}
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&flctx->flc_lock);
 
 	return 0;
 }
@@ -232,14 +232,14 @@ nlm_file_inuse(struct nlm_file *file)
 		return 1;
 
 	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
-		spin_lock(&inode->i_lock);
+		spin_lock(&flctx->flc_lock);
 		list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
 			if (fl->fl_lmops == &nlmsvc_lock_operations) {
-				spin_unlock(&inode->i_lock);
+				spin_unlock(&flctx->flc_lock);
 				return 1;
 			}
 		}
-		spin_unlock(&inode->i_lock);
+		spin_unlock(&flctx->flc_lock);
 	}
 	file->f_locks = 0;
 	return 0;

fs/nfs/delegation.c

@@ -93,22 +93,22 @@ static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_
 		goto out;
 
 	list = &flctx->flc_posix;
-	spin_lock(&inode->i_lock);
+	spin_lock(&flctx->flc_lock);
 restart:
 	list_for_each_entry(fl, list, fl_list) {
 		if (nfs_file_open_context(fl->fl_file) != ctx)
 			continue;
-		spin_unlock(&inode->i_lock);
+		spin_unlock(&flctx->flc_lock);
 		status = nfs4_lock_delegation_recall(fl, state, stateid);
 		if (status < 0)
 			goto out;
-		spin_lock(&inode->i_lock);
+		spin_lock(&flctx->flc_lock);
 	}
 	if (list == &flctx->flc_posix) {
 		list = &flctx->flc_flock;
 		goto restart;
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&flctx->flc_lock);
 out:
 	return status;
 }

fs/nfs/nfs4state.c

@@ -1376,12 +1376,12 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
 
 	/* Guard against delegation returns and new lock/unlock calls */
 	down_write(&nfsi->rwsem);
-	spin_lock(&inode->i_lock);
+	spin_lock(&flctx->flc_lock);
 restart:
 	list_for_each_entry(fl, list, fl_list) {
 		if (nfs_file_open_context(fl->fl_file)->state != state)
 			continue;
-		spin_unlock(&inode->i_lock);
+		spin_unlock(&flctx->flc_lock);
 		status = ops->recover_lock(state, fl);
 		switch (status) {
 		case 0:
@@ -1408,13 +1408,13 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
 			/* kill_proc(fl->fl_pid, SIGLOST, 1); */
 			status = 0;
 		}
-		spin_lock(&inode->i_lock);
+		spin_lock(&flctx->flc_lock);
 	}
 	if (list == &flctx->flc_posix) {
 		list = &flctx->flc_flock;
 		goto restart;
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&flctx->flc_lock);
 out:
 	up_write(&nfsi->rwsem);
 	return status;

fs/nfs/write.c

@@ -1206,7 +1206,7 @@ static int nfs_can_extend_write(struct file *file, struct page *page, struct ino
 
 	/* Check to see if there are whole file write locks */
 	ret = 0;
-	spin_lock(&inode->i_lock);
+	spin_lock(&flctx->flc_lock);
 	if (!list_empty(&flctx->flc_posix)) {
 		fl = list_first_entry(&flctx->flc_posix, struct file_lock,
 					fl_list);
@@ -1218,7 +1218,7 @@ static int nfs_can_extend_write(struct file *file, struct page *page, struct ino
 		if (fl->fl_type == F_WRLCK)
 			ret = 1;
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(&flctx->flc_lock);
 	return ret;
 }
 

fs/nfsd/nfs4state.c

@@ -5572,14 +5572,14 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
 	flctx = inode->i_flctx;
 
 	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
-		spin_lock(&inode->i_lock);
+		spin_lock(&flctx->flc_lock);
 		list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
 			if (fl->fl_owner == (fl_owner_t)lowner) {
 				status = true;
 				break;
 			}
 		}
-		spin_unlock(&inode->i_lock);
+		spin_unlock(&flctx->flc_lock);
 	}
 	fput(filp);
 	return status;

include/linux/fs.h

@@ -968,6 +968,7 @@ struct file_lock {
 };
 
 struct file_lock_context {
+	spinlock_t		flc_lock;
 	struct list_head	flc_flock;
 	struct list_head	flc_posix;
 	struct list_head	flc_lease;