Index: uspace/srv/fs/fat/fat_fat.c
===================================================================
--- uspace/srv/fs/fat/fat_fat.c	(revision 0ec862da203b9b0c3934013365d787a9b0f09bf5)
+++ uspace/srv/fs/fat/fat_fat.c	(revision 9f95a80687173cd8fd33f38d2dcde0d847a6d708)
@@ -54,4 +54,14 @@
 static futex_t fat_alloc_lock = FUTEX_INITIALIZER;
 
+/** Read block from file located on a FAT file system.
+ *
+ * @param bs		Buffer holding the boot sector of the file system.
+ * @param dev_handle	Device handle of the file system.
+ * @param firstc	First cluster used by the file. Can be zero if the file
+ *			is empty.
+ * @param offset	Offset in blocks.
+ *
+ * @return		Block structure holding the requested block.
+ */
 block_t *
 _fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
@@ -209,4 +219,12 @@
 }
 
+/** Mark cluster in one instance of FAT.
+ *
+ * @param bs		Buffer holding the boot sector for the file system.
+ * @param dev_handle	Device handle for the file system.
+ * @param fatno		Number of the FAT instance where to make the change.
+ * @param clst		Cluster which is to be marked.
+ * @param value		Value mark the cluster with.
+ */
 void
 fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
@@ -232,4 +250,11 @@
 }
 
+/** Replay the allocatoin of clusters in all shadow instances of FAT.
+ *
+ * @param bs		Buffer holding the boot sector of the file system.
+ * @param dev_handle	Device handle of the file system.
+ * @param lifo		Chain of allocated clusters.
+ * @param nclsts	Number of clusters in the lifo chain.
+ */
 void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,
     fat_cluster_t *lifo, unsigned nclsts)
@@ -246,4 +271,21 @@
 }
 
+/** Allocate clusters in FAT1.
+ *
+ * This function will attempt to allocate the requested number of clusters in
+ * the first FAT instance.  The FAT will be altered so that the allocated
+ * clusters form an independent chain (i.e. a chain which does not belong to any
+ * file yet).
+ *
+ * @param bs		Buffer holding the boot sector of the file system.
+ * @param dev_handle	Device handle of the file system.
+ * @param nclsts	Number of clusters to allocate.
+ * @param mcl		Output parameter where the first cluster in the chain
+ *			will be returned.
+ * @param lcl		Output parameter where the last cluster in the chain
+ *			will be returned.
+ *
+ * @return		EOK on success, a negative error code otherwise.
+ */
 int
 fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,
@@ -315,4 +357,10 @@
 }
 
+/** Append a cluster chain to the last file cluster in all FATs.
+ *
+ * @param bs		Buffer holding boot sector of the file system.
+ * @param nodep		Node representing the file.
+ * @param mcl		First cluster of the cluster chain to append.
+ */
 void fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl)
 {