btrfs: start transaction in btrfs_ioctl_setflags()

Inode attribute can be set through the FS_IOC_SETFLAGS ioctl.  This
flags also includes compression attribute for which we would set/reset
the compression extended attribute. While doing this there is a bit of
duplicate code, the following things happens twice:

- start/end_transaction
- inode_inc_iversion()
- current_time update to inode->i_ctime
- and btrfs_update_inode()

These are updated both at btrfs_ioctl_setflags() and btrfs_set_props()
as well.  This patch merges these two duplicate codes at
btrfs_ioctl_setflags().
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -192,6 +192,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	u64 old_flags;
 	unsigned int old_i_flags;
 	umode_t mode;
+	const char *comp = NULL;
 
 	if (!inode_owner_or_capable(inode))
 		return -EPERM;
@@ -283,14 +284,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	if (fsflags & FS_NOCOMP_FL) {
 		binode->flags &= ~BTRFS_INODE_COMPRESS;
 		binode->flags |= BTRFS_INODE_NOCOMPRESS;
-
-		/* set no-compression no need to validate prop here */
-		ret = btrfs_set_prop_trans(inode, "btrfs.compression", NULL,
-					   0, 0);
-		if (ret && ret != -ENODATA)
-			goto out_drop;
 	} else if (fsflags & FS_COMPR_FL) {
-		const char *comp;
 
 		if (IS_SWAPFILE(inode)) {
 			ret = -ETXTBSY;
@@ -300,36 +294,47 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 		binode->flags |= BTRFS_INODE_COMPRESS;
 		binode->flags &= ~BTRFS_INODE_NOCOMPRESS;
 
-		/* compress_type is already validated during mount options */
 		comp = btrfs_compress_type2str(fs_info->compress_type);
 		if (!comp || comp[0] == 0)
 			comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
-
-		ret = btrfs_set_prop_trans(inode, "btrfs.compression", comp,
-					   strlen(comp), 0);
-		if (ret)
-			goto out_drop;
-
 	} else {
-		/* reset prop, no need of validate prop here */
-		ret = btrfs_set_prop_trans(inode, "btrfs.compression", NULL,
-					   0, 0);
-		if (ret && ret != -ENODATA)
-			goto out_drop;
 		binode->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 	}
 
-	trans = btrfs_start_transaction(root, 1);
+	/*
+	 * 1 for inode item
+	 * 2 for properties
+	 */
+	trans = btrfs_start_transaction(root, 3);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
 		goto out_drop;
 	}
 
+	if (comp) {
+		ret = btrfs_set_prop(trans, inode, "btrfs.compression", comp,
+				     strlen(comp), 0);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_end_trans;
+		}
+		set_bit(BTRFS_INODE_COPY_EVERYTHING,
+			&BTRFS_I(inode)->runtime_flags);
+	} else {
+		ret = btrfs_set_prop(trans, inode, "btrfs.compression", NULL,
+				     0, 0);
+		if (ret && ret != -ENODATA) {
+			btrfs_abort_transaction(trans, ret);
+			goto out_end_trans;
+		}
+	}
+
 	btrfs_sync_inode_flags_to_i_flags(inode);
 	inode_inc_iversion(inode);
 	inode->i_ctime = current_time(inode);
 	ret = btrfs_update_inode(trans, root, inode);
 
+ out_end_trans:
 	btrfs_end_transaction(trans);
  out_drop:
 	if (ret) {