btrfs: fix string and comment grammatical issues and typos

Signed-off-by: Nicholas D Steeves <nsteeves@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 263823f..aacc707 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -384,7 +384,7 @@
 	/*
 	 * Things reading via commit roots that don't have normal protection,
 	 * like send, can have a really old block in cache that may point at a
-	 * block that has been free'd and re-allocated.  So don't clear uptodate
+	 * block that has been freed and re-allocated.  So don't clear uptodate
 	 * if we find an eb that is under IO (dirty/writeback) because we could
 	 * end up reading in the stale data and then writing it back out and
 	 * making everybody very sad.
@@ -418,7 +418,7 @@
 		/*
 		 * The super_block structure does not span the whole
 		 * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
-		 * is filled with zeros and is included in the checkum.
+		 * is filled with zeros and is included in the checksum.
 		 */
 		crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
 				crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
@@ -600,7 +600,7 @@
 
 		/*
 		 * Check to make sure that we don't point outside of the leaf,
-		 * just incase all the items are consistent to eachother, but
+		 * just in case all the items are consistent to each other, but
 		 * all point outside of the leaf.
 		 */
 		if (btrfs_item_end_nr(leaf, slot) >
@@ -3017,7 +3017,7 @@
 	}
 
 	/*
-	 * Mount does not set all options immediatelly, we can do it now and do
+	 * Mount does not set all options immediately, we can do it now and do
 	 * not have to wait for transaction commit
 	 */
 	btrfs_apply_pending_changes(fs_info);
@@ -3245,7 +3245,7 @@
 		btrfs_warn_rl_in_rcu(device->dev_root->fs_info,
 				"lost page write due to IO error on %s",
 					  rcu_str_deref(device->name));
-		/* note, we dont' set_buffer_write_io_error because we have
+		/* note, we don't set_buffer_write_io_error because we have
 		 * our own ways of dealing with the IO errors
 		 */
 		clear_buffer_uptodate(bh);