linux-kernel - [PATCH 1/2] btrfs: ioctl: Move the subvolume deleter code into a new function

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Date:   Sat, 11 Jan 2020 01:39:41 -0300
From:   Marcos Paulo de Souza <marcos.souza.org@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     dsterba@...e.com, linux-btrfs@...r.kernel.org,
        Marcos Paulo de Souza <mpdesouza@...e.com>, wqu@...e.com,
        Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>
Subject: [PATCH 1/2] btrfs: ioctl: Move the subvolume deleter code into a new function

From: Marcos Paulo de Souza <mpdesouza@...e.com>

This new function will be used by the next patch.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@...e.com>
---
 fs/btrfs/ioctl.c | 66 ++++++++++++++++++++++++++++--------------------
 1 file changed, 39 insertions(+), 27 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0fa1c386d020..dcceae4c5d28 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2835,44 +2835,27 @@ static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
 	return ret;
 }
 
-static noinline int btrfs_ioctl_snap_destroy(struct file *file,
-					     void __user *arg)
+static noinline int btrfs_subvolume_deleter(struct file *file,
+				struct dentry *parent, const char *subvol_name,
+				size_t namelen)
 {
-	struct dentry *parent = file->f_path.dentry;
-	struct btrfs_fs_info *fs_info = btrfs_sb(parent->d_sb);
 	struct dentry *dentry;
-	struct inode *dir = d_inode(parent);
+	struct btrfs_root *dest;
 	struct inode *inode;
+	struct inode *dir = d_inode(parent);
 	struct btrfs_root *root = BTRFS_I(dir)->root;
-	struct btrfs_root *dest = NULL;
-	struct btrfs_ioctl_vol_args *vol_args;
-	int namelen;
+	struct btrfs_fs_info *fs_info = root->fs_info;
 	int err = 0;
 
-	if (!S_ISDIR(dir->i_mode))
-		return -ENOTDIR;
-
-	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, '/') ||
-	    strncmp(vol_args->name, "..", namelen) == 0) {
-		err = -EINVAL;
-		goto out;
-	}
-
 	err = mnt_want_write_file(file);
 	if (err)
-		goto out;
-
+		return err;
 
 	err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
 	if (err == -EINTR)
 		goto out_drop_write;
-	dentry = lookup_one_len(vol_args->name, parent, namelen);
+
+	dentry = lookup_one_len(subvol_name, parent, namelen);
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
 		goto out_unlock_dir;
@@ -2880,7 +2863,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 
 	if (d_really_is_negative(dentry)) {
 		err = -ENOENT;
-		goto out_dput;
+		goto out_unlock_dir;
 	}
 
 	inode = d_inode(dentry);
@@ -2943,6 +2926,35 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 	inode_unlock(dir);
 out_drop_write:
 	mnt_drop_write_file(file);
+
+	return err;
+}
+
+static noinline int btrfs_ioctl_snap_destroy(struct file *file,
+					     void __user *arg)
+{
+	struct dentry *parent = file->f_path.dentry;
+	struct inode *dir = d_inode(parent);
+	struct btrfs_ioctl_vol_args *vol_args;
+	int namelen;
+	int err = 0;
+
+	if (!S_ISDIR(dir->i_mode))
+		return -ENOTDIR;
+
+	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, '/') ||
+	    strncmp(vol_args->name, "..", namelen) == 0) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = btrfs_subvolume_deleter(file, parent, vol_args->name, namelen);
 out:
 	kfree(vol_args);
 	return err;
-- 
2.24.0