From bb451d202b8bdb7e220e8acb953a44fd4818803e Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@newdream.net>
Date: Thu, 8 Apr 2010 10:34:50 -0700
Subject: [PATCH] filestore: use SNAP_DESTROY_ASYNC ioctl if available

---
 src/os/FileStore.cc  | 18 ++++++++++++++----
 src/os/FileStore.h   |  2 ++
 src/os/btrfs_ioctl.h |  2 ++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/os/FileStore.cc b/src/os/FileStore.cc
index 8ece0697d56e8..901d2a298e631 100644
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -558,9 +558,17 @@ int FileStore::_detect_fs()
       
 	// clean up
 	volargs.fd = 0;
-	r = ::ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &volargs);
-	if (r != 0) {
-	  dout(0) << "mount btrfs SNAP_DESTROY failed: " << strerror_r(-r, buf, sizeof(buf)) << dendl;
+	r = ::ioctl(fd, BTRFS_IOC_SNAP_DESTROY_ASYNC, &volargs);
+	if (r == 0) {
+	  dout(0) << "mount btrfs SNAP_DESTROY_ASYNC is supported" << dendl;
+	  btrfs_snap_destroy_async = true;
+	} else {
+	  dout(0) << "mount btrfs SNAP_DESTROY_ASYNC is NOT supported: "
+		  << strerror_r(-r, buf, sizeof(buf)) << dendl;
+	  r = ::ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &volargs);
+	  if (r != 0) {
+	    dout(0) << "mount btrfs SNAP_DESTROY failed: " << strerror_r(-r, buf, sizeof(buf)) << dendl;
+	  }
 	}
       } else {
 	dout(0) << "mount btrfs SNAP_CREATE_ASYNC is NOT supported: "
@@ -690,7 +698,9 @@ int FileStore::mount()
       // drop current
       snapargs.fd = 0;
       strcpy(snapargs.name, "current");
-      int r = ::ioctl(basedir_fd, BTRFS_IOC_SNAP_DESTROY, &snapargs);
+      int r = ::ioctl(basedir_fd,
+		      btrfs_snap_destroy_async ? BTRFS_IOC_SNAP_DESTROY_ASYNC:BTRFS_IOC_SNAP_DESTROY,
+		      &snapargs);
       if (r) {
 	char buf[80];
 	dout(0) << "error removing old current subvol: " << strerror_r(errno, buf, sizeof(buf)) << dendl;
diff --git a/src/os/FileStore.h b/src/os/FileStore.h
index dc26e15a34ba3..a8ddcbf78182c 100644
--- a/src/os/FileStore.h
+++ b/src/os/FileStore.h
@@ -49,6 +49,7 @@ class FileStore : public JournalingObjectStore {
   bool btrfs_snap_create;
   bool btrfs_snap_destroy;
   bool btrfs_snap_create_async;
+  bool btrfs_snap_destroy_async;
   bool btrfs_wait_sync;
   int fsid_fd, op_fd;
 
@@ -178,6 +179,7 @@ class FileStore : public JournalingObjectStore {
     btrfs_snap_create(false),
     btrfs_snap_destroy(false),
     btrfs_snap_create_async(false),
+    btrfs_snap_destroy_async(false),
     btrfs_wait_sync(false),
     fsid_fd(-1), op_fd(-1),
     attrs(this), fake_attrs(false), 
diff --git a/src/os/btrfs_ioctl.h b/src/os/btrfs_ioctl.h
index 21ff3c1d35377..0c33ab730d65b 100644
--- a/src/os/btrfs_ioctl.h
+++ b/src/os/btrfs_ioctl.h
@@ -184,4 +184,6 @@ struct btrfs_ioctl_space_args {
 #define BTRFS_IOC_WAIT_SYNC  _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
 #define BTRFS_IOC_SNAP_CREATE_ASYNC _IOW(BTRFS_IOCTL_MAGIC, 23, \
 				   struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_SNAP_DESTROY_ASYNC _IOW(BTRFS_IOCTL_MAGIC, 24, \
+				   struct btrfs_ioctl_vol_args)
 #endif
-- 
2.39.5