2 files changed, 93 insertions, 25 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index dc5a19ed07f3..e8a26a3aac3e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -224,7 +224,8 @@ static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 
 static noinline int create_subvol(struct btrfs_root *root,
                                   struct dentry *dentry,
-                                  char *name, int namelen)
+                                  char *name, int namelen,
+                                  u64 *async_transid)
 {
         struct btrfs_trans_handle *trans;
         struct btrfs_key key;
@@ -338,13 +339,19 @@ static noinline int create_subvol(struct btrfs_root *root,
 
         d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 fail:
-        err = btrfs_commit_transaction(trans, root);
+        if (async_transid) {
+                *async_transid = trans->transid;
+                err = btrfs_commit_transaction_async(trans, root, 1);
+        } else {
+                err = btrfs_commit_transaction(trans, root);
+        }
         if (err && !ret)
                 ret = err;
         return ret;
 }
 
-static int create_snapshot(struct btrfs_root *root, struct dentry *dentry)
+static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
+                           char *name, int namelen, u64 *async_transid)
 {
         struct inode *inode;
         struct btrfs_pending_snapshot *pending_snapshot;
@@ -373,7 +380,14 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry)
 
         list_add(&pending_snapshot->list,
                  &trans->transaction->pending_snapshots);
-        ret = btrfs_commit_transaction(trans, root->fs_info->extent_root);
+        if (async_transid) {
+                *async_transid = trans->transid;
+                ret = btrfs_commit_transaction_async(trans,
+                                     root->fs_info->extent_root, 1);
+        } else {
+                ret = btrfs_commit_transaction(trans,
+                                               root->fs_info->extent_root);
+        }
         BUG_ON(ret);
 
         ret = pending_snapshot->error;
@@ -412,7 +426,8 @@ static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
  */
 static noinline int btrfs_mksubvol(struct path *parent,
                                    char *name, int namelen,
-                                   struct btrfs_root *snap_src)
+                                   struct btrfs_root *snap_src,
+                                   u64 *async_transid)
 {
         struct inode *dir  = parent->dentry->d_inode;
         struct dentry *dentry;
@@ -443,10 +458,11 @@ static noinline int btrfs_mksubvol(struct path *parent,
                 goto out_up_read;
 
         if (snap_src) {
-                error = create_snapshot(snap_src, dentry);
+                error = create_snapshot(snap_src, dentry,
+                                        name, namelen, async_transid);
         } else {
                 error = create_subvol(BTRFS_I(dir)->root, dentry,
-                                      name, namelen);
+                                      name, namelen, async_transid);
         }
         if (!error)
                 fsnotify_mkdir(dir, dentry);
@@ -799,11 +815,13 @@ out_unlock:
         return ret;
 }
 
-static noinline int btrfs_ioctl_snap_create(struct file *file,
-                                            void __user *arg, int subvol)
+static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
+                                                    char *name,
+                                                    unsigned long fd,
+                                                    int subvol,
+                                                    u64 *transid)
 {
         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
-        struct btrfs_ioctl_vol_args *vol_args;
         struct file *src_file;
         int namelen;
         int ret = 0;
@@ -811,23 +829,18 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
         if (root->fs_info->sb->s_flags & MS_RDONLY)
                 return -EROFS;
 
-        vol_args = memdup_user(arg, sizeof(*vol_args));
-        if (IS_ERR(vol_args))
-                return PTR_ERR(vol_args);
-
-        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
-        namelen = strlen(vol_args->name);
-        if (strchr(vol_args->name, '/')) {
+        namelen = strlen(name);
+        if (strchr(name, '/')) {
                 ret = -EINVAL;
                 goto out;
         }
 
         if (subvol) {
-                ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
-                                     NULL);
+                ret = btrfs_mksubvol(&file->f_path, name, namelen,
+                                     NULL, transid);
         } else {
                 struct inode *src_inode;
-                src_file = fget(vol_args->fd);
+                src_file = fget(fd);
                 if (!src_file) {
                         ret = -EINVAL;
                         goto out;
@@ -841,12 +854,56 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
                         fput(src_file);
                         goto out;
                 }
-                ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
-                                     BTRFS_I(src_inode)->root);
+                ret = btrfs_mksubvol(&file->f_path, name, namelen,
+                                     BTRFS_I(src_inode)->root,
+                                     transid);
                 fput(src_file);
         }
 out:
+        return ret;
+}
+
+static noinline int btrfs_ioctl_snap_create(struct file *file,
+                                            void __user *arg, int subvol,
+                                            int async)
+{
+        struct btrfs_ioctl_vol_args *vol_args = NULL;
+        struct btrfs_ioctl_async_vol_args *async_vol_args = NULL;
+        char *name;
+        u64 fd;
+        u64 transid = 0;
+        int ret;
+
+        if (async) {
+                async_vol_args = memdup_user(arg, sizeof(*async_vol_args));
+                if (IS_ERR(async_vol_args))
+                        return PTR_ERR(async_vol_args);
+
+                name = async_vol_args->name;
+                fd = async_vol_args->fd;
+                async_vol_args->name[BTRFS_SNAPSHOT_NAME_MAX] = '\0';
+        } else {
+                vol_args = memdup_user(arg, sizeof(*vol_args));
+                if (IS_ERR(vol_args))
+                        return PTR_ERR(vol_args);
+                name = vol_args->name;
+                fd = vol_args->fd;
+                vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
+        }
+
+        ret = btrfs_ioctl_snap_create_transid(file, name, fd,
+                                              subvol, &transid);
+
+        if (!ret && async) {
+                if (copy_to_user(arg +
+                                offsetof(struct btrfs_ioctl_async_vol_args,
+                                transid), &transid, sizeof(transid)))
+                        return -EFAULT;
+        }
+
         kfree(vol_args);
+        kfree(async_vol_args);
+
         return ret;
 }
 
@@ -2072,9 +2129,11 @@ long btrfs_ioctl(struct file *file, unsigned int
         case FS_IOC_GETVERSION:
                 return btrfs_ioctl_getversion(file, argp);
         case BTRFS_IOC_SNAP_CREATE:
-                return btrfs_ioctl_snap_create(file, argp, 0);
+                return btrfs_ioctl_snap_create(file, argp, 0, 0);
+        case BTRFS_IOC_SNAP_CREATE_ASYNC:
+                return btrfs_ioctl_snap_create(file, argp, 0, 1);
         case BTRFS_IOC_SUBVOL_CREATE:
-                return btrfs_ioctl_snap_create(file, argp, 1);
+                return btrfs_ioctl_snap_create(file, argp, 1, 0);
         case BTRFS_IOC_SNAP_DESTROY:
                 return btrfs_ioctl_snap_destroy(file, argp);
         case BTRFS_IOC_DEFAULT_SUBVOL:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 16e1442523b7..17c99ebdf960 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -22,14 +22,21 @@
 
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_VOL_NAME_MAX 255
-#define BTRFS_PATH_NAME_MAX 4087
 
 /* this should be 4k */
+#define BTRFS_PATH_NAME_MAX 4087
 struct btrfs_ioctl_vol_args {
         __s64 fd;
         char name[BTRFS_PATH_NAME_MAX + 1];
 };
 
+#define BTRFS_SNAPSHOT_NAME_MAX 4079
+struct btrfs_ioctl_async_vol_args {
+        __s64 fd;
+        __u64 transid;
+        char name[BTRFS_SNAPSHOT_NAME_MAX + 1];
+};
+
 #define BTRFS_INO_LOOKUP_PATH_MAX 4080
 struct btrfs_ioctl_ino_lookup_args {
         __u64 treeid;
@@ -180,4 +187,6 @@ struct btrfs_ioctl_space_args {
                                     struct btrfs_ioctl_space_args)
 #define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64)
 #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_async_vol_args)
 #endif