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, 40 insertions, 25 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index e3671678b233..dddced525b69 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -604,7 +604,8 @@ out:
 	ceph_mdsc_release_dir_caps(req);
 }
 
-static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
+static int ceph_finish_async_create(struct inode *dir, struct inode *inode,
+				    struct dentry *dentry,
 				    struct file *file, umode_t mode,
 				    struct ceph_mds_request *req,
 				    struct ceph_acl_sec_ctx *as_ctx,
@@ -616,7 +617,6 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 	struct ceph_mds_reply_info_in iinfo = { .in = &in };
 	struct ceph_inode_info *ci = ceph_inode(dir);
 	struct ceph_dentry_info *di = ceph_dentry(dentry);
-	struct inode *inode;
 	struct timespec64 now;
 	struct ceph_string *pool_ns;
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
@@ -625,10 +625,6 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 
 	ktime_get_real_ts64(&now);
 
-	inode = ceph_get_inode(dentry->d_sb, vino);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
 	iinfo.inline_version = CEPH_INLINE_NONE;
 	iinfo.change_attr = 1;
 	ceph_encode_timespec64(&iinfo.btime, &now);
@@ -686,8 +682,7 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 		ceph_dir_clear_complete(dir);
 		if (!d_unhashed(dentry))
 			d_drop(dentry);
-		if (inode->i_state & I_NEW)
-			discard_new_inode(inode);
+		discard_new_inode(inode);
 	} else {
 		struct dentry *dn;
 
@@ -733,6 +728,7 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 	struct ceph_mds_client *mdsc = fsc->mdsc;
 	struct ceph_mds_request *req;
+	struct inode *new_inode = NULL;
 	struct dentry *dn;
 	struct ceph_acl_sec_ctx as_ctx = {};
 	bool try_async = ceph_test_mount_opt(fsc, ASYNC_DIROPS);
@@ -755,15 +751,16 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 	 */
 	flags &= ~O_TRUNC;
 
+retry:
 	if (flags & O_CREAT) {
 		if (ceph_quota_is_max_files_exceeded(dir))
 			return -EDQUOT;
-		err = ceph_pre_init_acls(dir, &mode, &as_ctx);
-		if (err < 0)
-			return err;
-		err = ceph_security_init_secctx(dentry, mode, &as_ctx);
-		if (err < 0)
+
+		new_inode = ceph_new_inode(dir, dentry, &mode, &as_ctx);
+		if (IS_ERR(new_inode)) {
+			err = PTR_ERR(new_inode);
 			goto out_ctx;
+		}
 		/* Async create can't handle more than a page of xattrs */
 		if (as_ctx.pagelist &&
 		    !list_is_singular(&as_ctx.pagelist->head))
@@ -772,7 +769,7 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 		/* If it's not being looked up, it's negative */
 		return -ENOENT;
 	}
-retry:
+
 	/* do the open */
 	req = prepare_open_request(dir->i_sb, flags, mode);
 	if (IS_ERR(req)) {
@@ -794,32 +791,47 @@ retry:
 		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;
-		}
-		if (try_async &&
-		    (req->r_dir_caps =
-		      try_prep_async_create(dir, dentry, &lo,
-					    &req->r_deleg_ino))) {
+
+		ceph_as_ctx_to_req(req, &as_ctx);
+
+		if (try_async && (req->r_dir_caps =
+				  try_prep_async_create(dir, dentry, &lo,
+							&req->r_deleg_ino))) {
+			struct ceph_vino vino = { .ino = req->r_deleg_ino,
+						  .snap = CEPH_NOSNAP };
 			struct ceph_dentry_info *di = ceph_dentry(dentry);
 
 			set_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags);
 			req->r_args.open.flags |= cpu_to_le32(CEPH_O_EXCL);
 			req->r_callback = ceph_async_create_cb;
 
+			/* Hash inode before RPC */
+			new_inode = ceph_get_inode(dir->i_sb, vino, new_inode);
+			if (IS_ERR(new_inode)) {
+				err = PTR_ERR(new_inode);
+				new_inode = NULL;
+				goto out_req;
+			}
+			WARN_ON_ONCE(!(new_inode->i_state & I_NEW));
+
 			spin_lock(&dentry->d_lock);
 			di->flags |= CEPH_DENTRY_ASYNC_CREATE;
 			spin_unlock(&dentry->d_lock);
 
 			err = ceph_mdsc_submit_request(mdsc, dir, req);
 			if (!err) {
-				err = ceph_finish_async_create(dir, dentry,
-							file, mode, req,
-							&as_ctx, &lo);
+				err = ceph_finish_async_create(dir, new_inode,
+							       dentry, file,
+							       mode, req,
+							       &as_ctx, &lo);
+				new_inode = NULL;
 			} else if (err == -EJUKEBOX) {
 				restore_deleg_ino(dir, req->r_deleg_ino);
 				ceph_mdsc_put_request(req);
+				discard_new_inode(new_inode);
+				ceph_release_acl_sec_ctx(&as_ctx);
+				memset(&as_ctx, 0, sizeof(as_ctx));
+				new_inode = NULL;
 				try_async = false;
 				ceph_put_string(rcu_dereference_raw(lo.pool_ns));
 				goto retry;
@@ -830,6 +842,8 @@ retry:
 	}
 
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
+	req->r_new_inode = new_inode;
+	new_inode = NULL;
 	err = ceph_mdsc_do_request(mdsc, (flags & O_CREAT) ? dir : NULL, req);
 	if (err == -ENOENT) {
 		dentry = ceph_handle_snapdir(req, dentry);
@@ -870,6 +884,7 @@ retry:
 	}
 out_req:
 	ceph_mdsc_put_request(req);
+	iput(new_inode);
 out_ctx:
 	ceph_release_acl_sec_ctx(&as_ctx);
 	dout("atomic_open result=%d\n", err);