btrfs: cleanup for open-coded alignment

Though most of the btrfs codes are using ALIGN macro for page alignment,
there are still some codes using open-coded alignment like the
following:
------
        u64 mask = ((u64)root->stripesize - 1);
        u64 ret = (val + mask) & ~mask;
------
Or even hidden one:
------
        num_bytes = (end - start + blocksize) & ~(blocksize - 1);
------

Sometimes these open-coded alignment is not so easy to understand for
newbie like me.

This commit changes the open-coded alignment to the ALIGN macro for a
better readability.

Also there is a previous patch from David Sterba with similar changes,
but the patch is for 3.2 kernel and seems not merged.
http://www.spinics.net/lists/linux-btrfs/msg12747.html

Cc: David Sterba <dave@jikos.cz>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 3 insertions, 6 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8520354f086e..5681a91ed400 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3431,7 +3431,7 @@ int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
         int ret = 0, committed = 0, alloc_chunk = 1;
 
         /* make sure bytes are sectorsize aligned */
-        bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
+        bytes = ALIGN(bytes, root->sectorsize);
 
         if (root == root->fs_info->tree_root ||
             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
@@ -3526,7 +3526,7 @@ void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
         struct btrfs_space_info *data_sinfo;
 
         /* make sure bytes are sectorsize aligned */
-        bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
+        bytes = ALIGN(bytes, root->sectorsize);
 
         data_sinfo = root->fs_info->data_sinfo;
         spin_lock(&data_sinfo->lock);
@@ -5607,10 +5607,7 @@ static u64 stripe_align(struct btrfs_root *root,
                         struct btrfs_block_group_cache *cache,
                         u64 val, u64 num_bytes)
 {
-        u64 mask;
-        u64 ret;
-        mask = ((u64)root->stripesize - 1);
-        ret = (val + mask) & ~mask;
+        u64 ret = ALIGN(val, root->stripesize);
         return ret;
 }