ceph: kstrdup() memory handling

Currently, there is no check for the kstrdup() for r_path2,
r_path1 and snapdir_name as various locations as there is a
possibility of failure during memory pressure. Therefore,
returning ENOMEM where the checks have been missed.
Signed-off-by: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>

fs/ceph/dir.c

@@ -337,16 +337,23 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 			ceph_mdsc_put_request(req);
 			return err;
 		}
-		req->r_inode = inode;
-		ihold(inode);
-		req->r_dentry = dget(file->f_path.dentry);
 		/* hints to request -> mds selection code */
 		req->r_direct_mode = USE_AUTH_MDS;
 		req->r_direct_hash = ceph_frag_value(frag);
 		req->r_direct_is_hash = true;
-		req->r_path2 = kstrdup(fi->last_name, GFP_NOFS);
+		if (fi->last_name) {
+			req->r_path2 = kstrdup(fi->last_name, GFP_NOFS);
+			if (!req->r_path2) {
+				ceph_mdsc_put_request(req);
+				return -ENOMEM;
+			}
+		}
 		req->r_readdir_offset = fi->next_offset;
 		req->r_args.readdir.frag = cpu_to_le32(frag);
+
+		req->r_inode = inode;
+		ihold(inode);
+		req->r_dentry = dget(file->f_path.dentry);
 		err = ceph_mdsc_do_request(mdsc, NULL, req);
 		if (err < 0) {
 			ceph_mdsc_put_request(req);
@@ -757,10 +764,15 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry,
 		err = PTR_ERR(req);
 		goto out;
 	}
-	req->r_dentry = dget(dentry);
-	req->r_num_caps = 2;
 	req->r_path2 = kstrdup(dest, GFP_NOFS);
+	if (!req->r_path2) {
+		err = -ENOMEM;
+		ceph_mdsc_put_request(req);
+		goto out;
+	}
 	req->r_locked_dir = dir;
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 	err = ceph_mdsc_do_request(mdsc, dir, req);

fs/ceph/super.c

@@ -345,6 +345,11 @@ static int parse_mount_options(struct ceph_mount_options **pfsopt,
 	fsopt->rsize = CEPH_RSIZE_DEFAULT;
 	fsopt->rasize = CEPH_RASIZE_DEFAULT;
 	fsopt->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);
+	if (!fsopt->snapdir_name) {
+		err = -ENOMEM;
+		goto out;
+	}
+
 	fsopt->caps_wanted_delay_min = CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT;
 	fsopt->caps_wanted_delay_max = CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT;
 	fsopt->cap_release_safety = CEPH_CAP_RELEASE_SAFETY_DEFAULT;
@@ -730,6 +735,11 @@ static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
 	if (IS_ERR(req))
 		return ERR_CAST(req);
 	req->r_path1 = kstrdup(path, GFP_NOFS);
+	if (!req->r_path1) {
+		root = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
 	req->r_ino1.ino = CEPH_INO_ROOT;
 	req->r_ino1.snap = CEPH_NOSNAP;
 	req->r_started = started;

fs/ceph/xattr.c

@@ -877,16 +877,23 @@ static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
 		err = PTR_ERR(req);
 		goto out;
 	}
-	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);
 	req->r_path2 = kstrdup(name, GFP_NOFS);
+	if (!req->r_path2) {
+		ceph_mdsc_put_request(req);
+		err = -ENOMEM;
+		goto out;
+	}
 
 	req->r_pagelist = pagelist;
 	pagelist = NULL;
 
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
+
 	dout("xattr.ver (before): %lld\n", ci->i_xattrs.version);
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
 	ceph_mdsc_put_request(req);
@@ -1019,12 +1026,14 @@ static int ceph_send_removexattr(struct dentry *dentry, const char *name)
 				       USE_AUTH_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
+	req->r_path2 = kstrdup(name, GFP_NOFS);
+	if (!req->r_path2)
+		return -ENOMEM;
+
 	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);
-
+	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
 	ceph_mdsc_put_request(req);
 	return err;