Btrfs: add SNAP_CREATE_ASYNC ioctl

[net-next-2.6.git] / fs / btrfs / ioctl.c

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index dc5a19ed07f3aa3391bc9b822e536ee4ca456908..e8a26a3aac3e9449ffa25f0b316dd6815dcb61f0 100644 (file)
--- 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: