ceph: use ihold when we already have an inode ref

We should use ihold whenever we already have a stable inode ref, even
when we aren't holding i_lock.  This avoids adding new and unnecessary
locking dependencies.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/addr.c

@@ -453,7 +453,7 @@ static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 	int err;
 	struct inode *inode = page->mapping->host;
 	BUG_ON(!inode);
-	igrab(inode);
+	ihold(inode);
 	err = writepage_nounlock(page, wbc);
 	unlock_page(page);
 	iput(inode);

fs/ceph/caps.c

@@ -2940,14 +2940,12 @@ void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
 	while (!list_empty(&mdsc->cap_dirty)) {
 		ci = list_first_entry(&mdsc->cap_dirty, struct ceph_inode_info,
 				      i_dirty_item);
-		inode = igrab(&ci->vfs_inode);
+		inode = &ci->vfs_inode;
+		ihold(inode);
 		dout("flush_dirty_caps %p\n", inode);
 		spin_unlock(&mdsc->cap_dirty_lock);
-		if (inode) {
-			ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_FLUSH,
-					NULL);
+		ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_FLUSH, NULL);
 		iput(inode);
-		}
 		spin_lock(&mdsc->cap_dirty_lock);
 	}
 	spin_unlock(&mdsc->cap_dirty_lock);

fs/ceph/dir.c

@@ -308,7 +308,8 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
 		req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
 		if (IS_ERR(req))
 			return PTR_ERR(req);
-		req->r_inode = igrab(inode);
+		req->r_inode = inode;
+		ihold(inode);
 		req->r_dentry = dget(filp->f_dentry);
 		/* hints to request -> mds selection code */
 		req->r_direct_mode = USE_AUTH_MDS;
@@ -787,10 +788,12 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 	err = ceph_mdsc_do_request(mdsc, dir, req);
-	if (err)
+	if (err) {
 		d_drop(dentry);
-	else if (!req->r_reply_info.head->is_dentry)
-		d_instantiate(dentry, igrab(old_dentry->d_inode));
+	} else if (!req->r_reply_info.head->is_dentry) {
+		ihold(old_dentry->d_inode);
+		d_instantiate(dentry, old_dentry->d_inode);
+	}
 	ceph_mdsc_put_request(req);
 	return err;
 }

fs/ceph/export.c

@@ -109,7 +109,7 @@ static struct dentry *__fh_to_dentry(struct super_block *sb,
 		err = ceph_mdsc_do_request(mdsc, NULL, req);
 		inode = req->r_target_inode;
 		if (inode)
-			igrab(inode);
+			ihold(inode);
 		ceph_mdsc_put_request(req);
 		if (!inode)
 			return ERR_PTR(-ESTALE);
@@ -167,7 +167,7 @@ static struct dentry *__cfh_to_dentry(struct super_block *sb,
 		err = ceph_mdsc_do_request(mdsc, NULL, req);
 		inode = req->r_target_inode;
 		if (inode)
-			igrab(inode);
+			ihold(inode);
 		ceph_mdsc_put_request(req);
 		if (!inode)
 			return ERR_PTR(err ? err : -ESTALE);

fs/ceph/file.c

@@ -191,7 +191,8 @@ int ceph_open(struct inode *inode, struct file *file)
 		err = PTR_ERR(req);
 		goto out;
 	}
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_num_caps = 1;
 	err = ceph_mdsc_do_request(mdsc, parent_inode, req);
 	if (!err)

fs/ceph/inode.c

@@ -1101,10 +1101,10 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
 				goto done;
 			}
 			req->r_dentry = dn;  /* may have spliced */
-			igrab(in);
+			ihold(in);
 		} else if (ceph_ino(in) == vino.ino &&
 			   ceph_snap(in) == vino.snap) {
-			igrab(in);
+			ihold(in);
 		} else {
 			dout(" %p links to %p %llx.%llx, not %llx.%llx\n",
 			     dn, in, ceph_ino(in), ceph_snap(in),
@@ -1144,7 +1144,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
 			goto done;
 		}
 		req->r_dentry = dn;  /* may have spliced */
-		igrab(in);
+		ihold(in);
 		rinfo->head->is_dentry = 1;  /* fool notrace handlers */
 	}
 
@@ -1328,7 +1328,7 @@ void ceph_queue_writeback(struct inode *inode)
 	if (queue_work(ceph_inode_to_client(inode)->wb_wq,
 		       &ceph_inode(inode)->i_wb_work)) {
 		dout("ceph_queue_writeback %p\n", inode);
-		igrab(inode);
+		ihold(inode);
 	} else {
 		dout("ceph_queue_writeback %p failed\n", inode);
 	}
@@ -1353,7 +1353,7 @@ void ceph_queue_invalidate(struct inode *inode)
 	if (queue_work(ceph_inode_to_client(inode)->pg_inv_wq,
 		       &ceph_inode(inode)->i_pg_inv_work)) {
 		dout("ceph_queue_invalidate %p\n", inode);
-		igrab(inode);
+		ihold(inode);
 	} else {
 		dout("ceph_queue_invalidate %p failed\n", inode);
 	}
@@ -1477,7 +1477,7 @@ void ceph_queue_vmtruncate(struct inode *inode)
 	if (queue_work(ceph_sb_to_client(inode->i_sb)->trunc_wq,
 		       &ci->i_vmtruncate_work)) {
 		dout("ceph_queue_vmtruncate %p\n", inode);
-		igrab(inode);
+		ihold(inode);
 	} else {
 		dout("ceph_queue_vmtruncate %p failed, pending=%d\n",
 		     inode, ci->i_truncate_pending);
@@ -1738,7 +1738,8 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr)
 		__mark_inode_dirty(inode, inode_dirty_flags);
 
 	if (mask) {
-		req->r_inode = igrab(inode);
+		req->r_inode = inode;
+		ihold(inode);
 		req->r_inode_drop = release;
 		req->r_args.setattr.mask = cpu_to_le32(mask);
 		req->r_num_caps = 1;
@@ -1779,7 +1780,8 @@ int ceph_do_getattr(struct inode *inode, int mask)
 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_num_caps = 1;
 	req->r_args.getattr.mask = cpu_to_le32(mask);
 	err = ceph_mdsc_do_request(mdsc, NULL, req);

fs/ceph/ioctl.c

@@ -73,7 +73,8 @@ static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
 				       USE_AUTH_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_inode_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_EXCL;
 
 	req->r_args.setlayout.layout.fl_stripe_unit =
@@ -135,7 +136,8 @@ static long ceph_ioctl_set_layout_policy (struct file *file, void __user *arg)
 
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 
 	req->r_args.setlayout.layout.fl_stripe_unit =
 			cpu_to_le32(l.stripe_unit);

fs/ceph/locks.c

@@ -23,7 +23,8 @@ static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
 	req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 
 	/* mds requires start and length rather than start and end */
 	if (LLONG_MAX == fl->fl_end)

fs/ceph/snap.c

@@ -722,7 +722,7 @@ static void flush_snaps(struct ceph_mds_client *mdsc)
 		ci = list_first_entry(&mdsc->snap_flush_list,
 				struct ceph_inode_info, i_snap_flush_item);
 		inode = &ci->vfs_inode;
-		igrab(inode);
+		ihold(inode);
 		spin_unlock(&mdsc->snap_flush_lock);
 		spin_lock(&inode->i_lock);
 		__ceph_flush_snaps(ci, &session, 0);

fs/ceph/xattr.c

@@ -665,7 +665,8 @@ static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
 		err = PTR_ERR(req);
 		goto out;
 	}
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
 	req->r_num_caps = 1;
 	req->r_args.setxattr.flags = cpu_to_le32(flags);
@@ -795,7 +796,8 @@ static int ceph_send_removexattr(struct dentry *dentry, const char *name)
 				       USE_AUTH_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
 	req->r_num_caps = 1;
 	req->r_path2 = kstrdup(name, GFP_NOFS);