Commit 695a0d0d authored by Josef Bacik's avatar Josef Bacik

Btrfs: add a comment explaining what btrfs_cont_expand does

Everytime I have to deal with btrfs_cont_expand I stare at it for 20 minutes
trying to remember what exactly it does and why the hell we need it.  So add a
comment to save future-Josef some time.  Thanks,
Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
parent 930f028a
......@@ -3557,6 +3557,12 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
return ret;
}
/*
* This function puts in dummy file extents for the area we're creating a hole
* for. So if we are truncating this file to a larger size we need to insert
* these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
* the range between oldsize and size
*/
int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
{
struct btrfs_trans_handle *trans;
......
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