ceph: preallocate inode for ops that may create one

When creating a new inode, we need to determine the crypto context
before we can transmit the RPC. The fscrypt API has a routine for getting
a crypto context before a create occurs, but it requires an inode.

Change the ceph code to preallocate an inode in advance of a create of
any sort (open(), mknod(), symlink(), etc). Move the existing code that
generates the ACL and SELinux blobs into this routine since that's
mostly common across all the different codepaths.

In most cases, we just want to allow ceph_fill_trace to use that inode
after the reply comes in, so add a new field to the MDS request for it
(r_new_inode).

The async create codepath is a bit different though. In that case, we
want to hash the inode in advance of the RPC so that it can be used
before the reply comes in. If the call subsequently fails with
-EJUKEBOX, then just put the references and clean up the as_ctx. Note
that with this change, we now need to regenerate the as_ctx when this
occurs, but it's quite rare for it to happen.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 38 insertions, 32 deletions

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index bdcffb04513f..31fac215a6a0 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -865,13 +865,6 @@ static int ceph_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		goto out;
 	}
 
-	err = ceph_pre_init_acls(dir, &mode, &as_ctx);
-	if (err < 0)
-		goto out;
-	err = ceph_security_init_secctx(dentry, mode, &as_ctx);
-	if (err < 0)
-		goto out;
-
 	dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
 	     dir, dentry, mode, rdev);
 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
@@ -879,6 +872,14 @@ static int ceph_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		err = PTR_ERR(req);
 		goto out;
 	}
+
+	req->r_new_inode = ceph_new_inode(dir, dentry, &mode, &as_ctx);
+	if (IS_ERR(req->r_new_inode)) {
+		err = PTR_ERR(req->r_new_inode);
+		req->r_new_inode = NULL;
+		goto out_req;
+	}
+
 	req->r_dentry = dget(dentry);
 	req->r_num_caps = 2;
 	req->r_parent = dir;
@@ -889,13 +890,13 @@ static int ceph_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL |
 			     CEPH_CAP_XATTR_EXCL;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
-	if (as_ctx.pagelist) {
-		req->r_pagelist = as_ctx.pagelist;
-		as_ctx.pagelist = NULL;
-	}
+
+	ceph_as_ctx_to_req(req, &as_ctx);
+
 	err = ceph_mdsc_do_request(mdsc, dir, req);
 	if (!err && !req->r_reply_info.head->is_dentry)
 		err = ceph_handle_notrace_create(dir, dentry);
+out_req:
 	ceph_mdsc_put_request(req);
 out:
 	if (!err)
@@ -918,6 +919,7 @@ static int ceph_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
 	struct ceph_mds_request *req;
 	struct ceph_acl_sec_ctx as_ctx = {};
+	umode_t mode = S_IFLNK | 0777;
 	int err;
 
 	if (ceph_snap(dir) != CEPH_NOSNAP)
@@ -932,21 +934,24 @@ static int ceph_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		goto out;
 	}
 
-	err = ceph_security_init_secctx(dentry, S_IFLNK | 0777, &as_ctx);
-	if (err < 0)
-		goto out;
-
 	dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
 	if (IS_ERR(req)) {
 		err = PTR_ERR(req);
 		goto out;
 	}
+
+	req->r_new_inode = ceph_new_inode(dir, dentry, &mode, &as_ctx);
+	if (IS_ERR(req->r_new_inode)) {
+		err = PTR_ERR(req->r_new_inode);
+		req->r_new_inode = NULL;
+		goto out_req;
+	}
+
 	req->r_path2 = kstrdup(dest, GFP_KERNEL);
 	if (!req->r_path2) {
 		err = -ENOMEM;
-		ceph_mdsc_put_request(req);
-		goto out;
+		goto out_req;
 	}
 	req->r_parent = dir;
 	ihold(dir);
@@ -957,13 +962,13 @@ static int ceph_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL |
 			     CEPH_CAP_XATTR_EXCL;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
-	if (as_ctx.pagelist) {
-		req->r_pagelist = as_ctx.pagelist;
-		as_ctx.pagelist = NULL;
-	}
+
+	ceph_as_ctx_to_req(req, &as_ctx);
+
 	err = ceph_mdsc_do_request(mdsc, dir, req);
 	if (!err && !req->r_reply_info.head->is_dentry)
 		err = ceph_handle_notrace_create(dir, dentry);
+out_req:
 	ceph_mdsc_put_request(req);
 out:
 	if (err)
@@ -1004,13 +1009,6 @@ static int ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		goto out;
 	}
 
-	mode |= S_IFDIR;
-	err = ceph_pre_init_acls(dir, &mode, &as_ctx);
-	if (err < 0)
-		goto out;
-	err = ceph_security_init_secctx(dentry, mode, &as_ctx);
-	if (err < 0)
-		goto out;
 
 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
 	if (IS_ERR(req)) {
@@ -1018,6 +1016,14 @@ static int ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		goto out;
 	}
 
+	mode |= S_IFDIR;
+	req->r_new_inode = ceph_new_inode(dir, dentry, &mode, &as_ctx);
+	if (IS_ERR(req->r_new_inode)) {
+		err = PTR_ERR(req->r_new_inode);
+		req->r_new_inode = NULL;
+		goto out_req;
+	}
+
 	req->r_dentry = dget(dentry);
 	req->r_num_caps = 2;
 	req->r_parent = dir;
@@ -1027,15 +1033,15 @@ static int ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL |
 			     CEPH_CAP_XATTR_EXCL;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
-	if (as_ctx.pagelist) {
-		req->r_pagelist = as_ctx.pagelist;
-		as_ctx.pagelist = NULL;
-	}
+
+	ceph_as_ctx_to_req(req, &as_ctx);
+
 	err = ceph_mdsc_do_request(mdsc, dir, req);
 	if (!err &&
 	    !req->r_reply_info.head->is_target &&
 	    !req->r_reply_info.head->is_dentry)
 		err = ceph_handle_notrace_create(dir, dentry);
+out_req:
 	ceph_mdsc_put_request(req);
 out:
 	if (!err)