[PATCH] ext4: minor defrag code improvements

[Eric Whitney <enwlinux@gmail.com>]

Modify two error paths returning EBUSY for bad argument file types to
return EOPNOTSUPP instead.  Move an extent tree search whose results are
only occasionally required to the site always requiring them for
improved efficiency.  Address a few typos.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
---
 fs/ext4/move_extent.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 701f1d6a217f..4e4b0452106e 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -472,19 +472,17 @@ mext_check_arguments(struct inode *orig_inode,
 	if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
 		return -EPERM;
 
-	/* Ext4 move extent does not support swapfile */
+	/* Ext4 move extent does not support swap files */
 	if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
-		ext4_debug("ext4 move extent: The argument files should "
-			"not be swapfile [ino:orig %lu, donor %lu]\n",
+		ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n",
 			orig_inode->i_ino, donor_inode->i_ino);
-		return -EBUSY;
+		return -EOPNOTSUPP;
 	}
 
 	if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) {
-		ext4_debug("ext4 move extent: The argument files should "
-			"not be quota files [ino:orig %lu, donor %lu]\n",
+		ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n",
 			orig_inode->i_ino, donor_inode->i_ino);
-		return -EBUSY;
+		return -EOPNOTSUPP;
 	}
 
 	/* Ext4 move extent supports only extent based file */
@@ -631,11 +629,11 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
 		if (ret)
 			goto out;
 		ex = path[path->p_depth].p_ext;
-		next_blk = ext4_ext_next_allocated_block(path);
 		cur_blk = le32_to_cpu(ex->ee_block);
 		cur_len = ext4_ext_get_actual_len(ex);
 		/* Check hole before the start pos */
 		if (cur_blk + cur_len - 1 < o_start) {
+			next_blk = ext4_ext_next_allocated_block(path);
 			if (next_blk == EXT_MAX_BLOCKS) {
 				ret = -ENODATA;
 				goto out;
@@ -663,7 +661,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
 		donor_page_index = d_start >> (PAGE_SHIFT -
 					       donor_inode->i_blkbits);
 		offset_in_page = o_start % blocks_per_page;
-		if (cur_len > blocks_per_page- offset_in_page)
+		if (cur_len > blocks_per_page - offset_in_page)
 			cur_len = blocks_per_page - offset_in_page;
 		/*
 		 * Up semaphore to avoid following problems:
-- 
2.30.2