ceph: simplify calling of ceph_get_fmode()

Originally, calling ceph_get_fmode() for open files is by thread that
handles request reply. There is a small window between updating caps and
and waking the request initiator. We need to prevent ceph_check_caps()
from releasing wanted caps in the window.

Previous patches made fill_inode() call __ceph_touch_fmode() for open file
requests. This prevented ceph_check_caps() from releasing wanted caps for
'caps_wanted_delay_min' seconds, enough for request initiator to get
woken up and call ceph_get_fmode().

This allows us to now call ceph_get_fmode() in ceph_open() instead.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -608,7 +608,7 @@ static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
  */
 void ceph_add_cap(struct inode *inode,
 		  struct ceph_mds_session *session, u64 cap_id,
-		  int fmode, unsigned issued, unsigned wanted,
+		  unsigned issued, unsigned wanted,
 		  unsigned seq, unsigned mseq, u64 realmino, int flags,
 		  struct ceph_cap **new_cap)
 {
@@ -624,13 +624,6 @@ void ceph_add_cap(struct inode *inode,
 	dout("add_cap %p mds%d cap %llx %s seq %d\n", inode,
 	     session->s_mds, cap_id, ceph_cap_string(issued), seq);
 
-	/*
-	 * If we are opening the file, include file mode wanted bits
-	 * in wanted.
-	 */
-	if (fmode >= 0)
-		wanted |= ceph_caps_for_mode(fmode);
-
 	spin_lock(&session->s_gen_ttl_lock);
 	gen = session->s_cap_gen;
 	spin_unlock(&session->s_gen_ttl_lock);
@@ -755,9 +748,6 @@ void ceph_add_cap(struct inode *inode,
 	cap->issue_seq = seq;
 	cap->mseq = mseq;
 	cap->cap_gen = gen;
-
-	if (fmode >= 0)
-		__ceph_get_fmode(ci, fmode);
 }
 
 /*
@@ -3707,7 +3697,7 @@ retry:
 		/* add placeholder for the export tagert */
 		int flag = (cap == ci->i_auth_cap) ? CEPH_CAP_FLAG_AUTH : 0;
 		tcap = new_cap;
-		ceph_add_cap(inode, tsession, t_cap_id, -1, issued, 0,
+		ceph_add_cap(inode, tsession, t_cap_id, issued, 0,
 			     t_seq - 1, t_mseq, (u64)-1, flag, &new_cap);
 
 		if (!list_empty(&ci->i_cap_flush_list) &&
@@ -3812,7 +3802,7 @@ retry:
 	__ceph_caps_issued(ci, &issued);
 	issued |= __ceph_caps_dirty(ci);
 
-	ceph_add_cap(inode, session, cap_id, -1, caps, wanted, seq, mseq,
+	ceph_add_cap(inode, session, cap_id, caps, wanted, seq, mseq,
 		     realmino, CEPH_CAP_FLAG_AUTH, &new_cap);
 
 	ocap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL;
@@ -4165,16 +4155,6 @@ void ceph_get_fmode(struct ceph_inode_info *ci, int fmode, int count)
 	spin_unlock(&ci->i_ceph_lock);
 }
 
-void __ceph_get_fmode(struct ceph_inode_info *ci, int fmode)
-{
-	int i;
-	int bits = (fmode << 1) | 1;
-	for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
-		if (bits & (1 << i))
-			ci->i_nr_by_mode[i]++;
-	}
-}
-
 /*
  * Drop open file reference.  If we were the last open file,
  * we may need to release capabilities to the MDS (or schedule

fs/ceph/file.c

@@ -212,10 +212,8 @@ static int ceph_init_file_info(struct inode *inode, struct file *file,
 	if (isdir) {
 		struct ceph_dir_file_info *dfi =
 			kmem_cache_zalloc(ceph_dir_file_cachep, GFP_KERNEL);
-		if (!dfi) {
+		if (!dfi)
-			ceph_put_fmode(ci, fmode, 1); /* clean up */
 			return -ENOMEM;
-		}
 
 		file->private_data = dfi;
 		fi = &dfi->file_info;
@@ -223,15 +221,15 @@ static int ceph_init_file_info(struct inode *inode, struct file *file,
 		dfi->readdir_cache_idx = -1;
 	} else {
 		fi = kmem_cache_zalloc(ceph_file_cachep, GFP_KERNEL);
-		if (!fi) {
+		if (!fi)
-			ceph_put_fmode(ci, fmode, 1); /* clean up */
 			return -ENOMEM;
-		}
 
 		file->private_data = fi;
 	}
 
+	ceph_get_fmode(ci, fmode, 1);
 	fi->fmode = fmode;
+
 	spin_lock_init(&fi->rw_contexts_lock);
 	INIT_LIST_HEAD(&fi->rw_contexts);
 	fi->meta_err = errseq_sample(&ci->i_meta_err);
@@ -263,7 +261,6 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 	case S_IFLNK:
 		dout("init_file %p %p 0%o (symlink)\n", inode, file,
 		     inode->i_mode);
-		ceph_put_fmode(ceph_inode(inode), fmode, 1); /* clean up */
 		break;
 
 	default:
@@ -273,7 +270,6 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 		 * we need to drop the open ref now, since we don't
 		 * have .release set to ceph_release.
 		 */
-		ceph_put_fmode(ceph_inode(inode), fmode, 1); /* clean up */
 		BUG_ON(inode->i_fop->release == ceph_release);
 
 		/* call the proper open fop */
@@ -327,7 +323,6 @@ int ceph_renew_caps(struct inode *inode, int fmode)
 	req->r_inode = inode;
 	ihold(inode);
 	req->r_num_caps = 1;
-	req->r_fmode = -1;
 
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
 	ceph_mdsc_put_request(req);
@@ -373,9 +368,6 @@ int ceph_open(struct inode *inode, struct file *file)
 
 	/* trivially open snapdir */
 	if (ceph_snap(inode) == CEPH_SNAPDIR) {
-		spin_lock(&ci->i_ceph_lock);
-		__ceph_get_fmode(ci, fmode);
-		spin_unlock(&ci->i_ceph_lock);
 		return ceph_init_file(inode, file, fmode);
 	}
 
@@ -393,7 +385,7 @@ int ceph_open(struct inode *inode, struct file *file)
 		dout("open %p fmode %d want %s issued %s using existing\n",
 		     inode, fmode, ceph_cap_string(wanted),
 		     ceph_cap_string(issued));
-		__ceph_get_fmode(ci, fmode);
+		__ceph_touch_fmode(ci, mdsc, fmode);
 		spin_unlock(&ci->i_ceph_lock);
 
 		/* adjust wanted? */
@@ -405,7 +397,6 @@ int ceph_open(struct inode *inode, struct file *file)
 		return ceph_init_file(inode, file, fmode);
 	} else if (ceph_snap(inode) != CEPH_NOSNAP &&
 		   (ci->i_snap_caps & wanted) == wanted) {
-		__ceph_get_fmode(ci, fmode);
 		__ceph_touch_fmode(ci, mdsc, fmode);
 		spin_unlock(&ci->i_ceph_lock);
 		return ceph_init_file(inode, file, fmode);
@@ -782,8 +773,6 @@ retry:
 		err = finish_open(file, dentry, ceph_open);
 	}
 out_req:
-	if (!req->r_err && req->r_target_inode)
-		ceph_put_fmode(ceph_inode(req->r_target_inode), req->r_fmode, 1);
 	ceph_mdsc_put_request(req);
 out_ctx:
 	ceph_release_acl_sec_ctx(&as_ctx);

fs/ceph/inode.c

@@ -970,7 +970,7 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
 		if (ceph_snap(inode) == CEPH_NOSNAP) {
 			ceph_add_cap(inode, session,
 				     le64_to_cpu(info->cap.cap_id),
-				     cap_fmode, info_caps,
+				     info_caps,
 				     le32_to_cpu(info->cap.wanted),
 				     le32_to_cpu(info->cap.seq),
 				     le32_to_cpu(info->cap.mseq),
@@ -995,13 +995,7 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
 			dout(" %p got snap_caps %s\n", inode,
 			     ceph_cap_string(info_caps));
 			ci->i_snap_caps |= info_caps;
-			if (cap_fmode >= 0)
-				__ceph_get_fmode(ci, cap_fmode);
 		}
-	} else if (cap_fmode >= 0) {
-		pr_warn("mds issued no caps on %llx.%llx\n",
-			   ceph_vinop(inode));
-		__ceph_get_fmode(ci, cap_fmode);
 	}
 
 	if (iinfo->inline_version > 0 &&

fs/ceph/super.h

@@ -1050,7 +1050,7 @@ extern struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
 				     struct ceph_cap_reservation *ctx);
 extern void ceph_add_cap(struct inode *inode,
 			 struct ceph_mds_session *session, u64 cap_id,
-			 int fmode, unsigned issued, unsigned wanted,
+			 unsigned issued, unsigned wanted,
 			 unsigned cap, unsigned seq, u64 realmino, int flags,
 			 struct ceph_cap **new_cap);
 extern void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release);
@@ -1096,7 +1096,6 @@ extern int ceph_try_get_caps(struct inode *inode,
 			     int need, int want, bool nonblock, int *got);
 
 /* for counting open files by mode */
-extern void __ceph_get_fmode(struct ceph_inode_info *ci, int mode);
 extern void ceph_get_fmode(struct ceph_inode_info *ci, int mode, int count);
 extern void ceph_put_fmode(struct ceph_inode_info *ci, int mode, int count);
 extern void __ceph_touch_fmode(struct ceph_inode_info *ci,