Index: uspace/lib/ext4/include/ext4/balloc.h
===================================================================
--- uspace/lib/ext4/include/ext4/balloc.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/balloc.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -37,10 +37,10 @@
 #include "types.h"
 
-extern int ext4_balloc_free_block(ext4_inode_ref_t *, uint32_t);
-extern int ext4_balloc_free_blocks(ext4_inode_ref_t *, uint32_t, uint32_t);
+extern errno_t ext4_balloc_free_block(ext4_inode_ref_t *, uint32_t);
+extern errno_t ext4_balloc_free_blocks(ext4_inode_ref_t *, uint32_t, uint32_t);
 extern uint32_t ext4_balloc_get_first_data_block_in_group(ext4_superblock_t *,
     ext4_block_group_ref_t *);
-extern int ext4_balloc_alloc_block(ext4_inode_ref_t *, uint32_t *);
-extern int ext4_balloc_try_alloc_block(ext4_inode_ref_t *, uint32_t, bool *);
+extern errno_t ext4_balloc_alloc_block(ext4_inode_ref_t *, uint32_t *);
+extern errno_t ext4_balloc_try_alloc_block(ext4_inode_ref_t *, uint32_t, bool *);
 
 #endif
Index: uspace/lib/ext4/include/ext4/bitmap.h
===================================================================
--- uspace/lib/ext4/include/ext4/bitmap.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/bitmap.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -40,7 +40,7 @@
 extern void ext4_bitmap_set_bit(uint8_t *, uint32_t);
 extern bool ext4_bitmap_is_free_bit(uint8_t *, uint32_t);
-extern int ext4_bitmap_find_free_byte_and_set_bit(uint8_t *, uint32_t,
+extern errno_t ext4_bitmap_find_free_byte_and_set_bit(uint8_t *, uint32_t,
     uint32_t *, uint32_t);
-extern int ext4_bitmap_find_free_bit_and_set(uint8_t *, uint32_t, uint32_t *,
+extern errno_t ext4_bitmap_find_free_bit_and_set(uint8_t *, uint32_t, uint32_t *,
     uint32_t);
 
Index: uspace/lib/ext4/include/ext4/directory.h
===================================================================
--- uspace/lib/ext4/include/ext4/directory.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/directory.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -53,25 +53,25 @@
     ext4_directory_entry_ll_t *, uint8_t);
 
-extern int ext4_directory_iterator_init(ext4_directory_iterator_t *,
+extern errno_t ext4_directory_iterator_init(ext4_directory_iterator_t *,
     ext4_inode_ref_t *, aoff64_t);
-extern int ext4_directory_iterator_next(ext4_directory_iterator_t *);
-extern int ext4_directory_iterator_fini(ext4_directory_iterator_t *);
+extern errno_t ext4_directory_iterator_next(ext4_directory_iterator_t *);
+extern errno_t ext4_directory_iterator_fini(ext4_directory_iterator_t *);
 
 extern void ext4_directory_write_entry(ext4_superblock_t *,
     ext4_directory_entry_ll_t *, uint16_t, ext4_inode_ref_t *,
     const char *, size_t);
-extern int ext4_directory_add_entry(ext4_inode_ref_t *, const char *,
+extern errno_t ext4_directory_add_entry(ext4_inode_ref_t *, const char *,
     ext4_inode_ref_t *);
-extern int ext4_directory_find_entry(ext4_directory_search_result_t *,
+extern errno_t ext4_directory_find_entry(ext4_directory_search_result_t *,
     ext4_inode_ref_t *, const char *);
-extern int ext4_directory_remove_entry(ext4_inode_ref_t *, const char *);
+extern errno_t ext4_directory_remove_entry(ext4_inode_ref_t *, const char *);
 
-extern int ext4_directory_try_insert_entry(ext4_superblock_t *, block_t *,
+extern errno_t ext4_directory_try_insert_entry(ext4_superblock_t *, block_t *,
     ext4_inode_ref_t *, const char *, uint32_t);
 
-extern int ext4_directory_find_in_block(block_t *, ext4_superblock_t *, size_t,
+extern errno_t ext4_directory_find_in_block(block_t *, ext4_superblock_t *, size_t,
     const char *, ext4_directory_entry_ll_t **);
 
-extern int ext4_directory_destroy_result(ext4_directory_search_result_t *);
+extern errno_t ext4_directory_destroy_result(ext4_directory_search_result_t *);
 
 #endif
Index: uspace/lib/ext4/include/ext4/directory_index.h
===================================================================
--- uspace/lib/ext4/include/ext4/directory_index.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/directory_index.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -65,8 +65,8 @@
     uint32_t);
 
-extern int ext4_directory_dx_init(ext4_inode_ref_t *);
-extern int ext4_directory_dx_find_entry(ext4_directory_search_result_t *,
+extern errno_t ext4_directory_dx_init(ext4_inode_ref_t *);
+extern errno_t ext4_directory_dx_find_entry(ext4_directory_search_result_t *,
     ext4_inode_ref_t *, size_t, const char *);
-extern int ext4_directory_dx_add_entry(ext4_inode_ref_t *, ext4_inode_ref_t *,
+extern errno_t ext4_directory_dx_add_entry(ext4_inode_ref_t *, ext4_inode_ref_t *,
     const char *);
 
Index: uspace/lib/ext4/include/ext4/extent.h
===================================================================
--- uspace/lib/ext4/include/ext4/extent.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/extent.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -61,8 +61,8 @@
 extern void ext4_extent_header_set_generation(ext4_extent_header_t *, uint32_t);
 
-extern int ext4_extent_find_block(ext4_inode_ref_t *, uint32_t, uint32_t *);
-extern int ext4_extent_release_blocks_from(ext4_inode_ref_t *, uint32_t);
+extern errno_t ext4_extent_find_block(ext4_inode_ref_t *, uint32_t, uint32_t *);
+extern errno_t ext4_extent_release_blocks_from(ext4_inode_ref_t *, uint32_t);
 
-extern int ext4_extent_append_block(ext4_inode_ref_t *, uint32_t *, uint32_t *,
+extern errno_t ext4_extent_append_block(ext4_inode_ref_t *, uint32_t *, uint32_t *,
     bool);
 
Index: uspace/lib/ext4/include/ext4/filesystem.h
===================================================================
--- uspace/lib/ext4/include/ext4/filesystem.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/filesystem.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -39,8 +39,8 @@
 #include "ext4/types.h"
 
-extern int ext4_filesystem_probe(service_id_t);
-extern int ext4_filesystem_open(ext4_instance_t *, service_id_t,
+extern errno_t ext4_filesystem_probe(service_id_t);
+extern errno_t ext4_filesystem_open(ext4_instance_t *, service_id_t,
     enum cache_mode, aoff64_t *, ext4_filesystem_t **);
-extern int ext4_filesystem_close(ext4_filesystem_t *);
+extern errno_t ext4_filesystem_close(ext4_filesystem_t *);
 extern uint32_t ext4_filesystem_blockaddr2_index_in_group(ext4_superblock_t *,
     uint32_t);
@@ -48,20 +48,20 @@
     uint32_t, uint32_t);
 extern uint32_t ext4_filesystem_blockaddr2group(ext4_superblock_t *, uint64_t);
-extern int ext4_filesystem_get_block_group_ref(ext4_filesystem_t *, uint32_t,
+extern errno_t ext4_filesystem_get_block_group_ref(ext4_filesystem_t *, uint32_t,
     ext4_block_group_ref_t **);
-extern int ext4_filesystem_put_block_group_ref(ext4_block_group_ref_t *);
-extern int ext4_filesystem_get_inode_ref(ext4_filesystem_t *, uint32_t,
+extern errno_t ext4_filesystem_put_block_group_ref(ext4_block_group_ref_t *);
+extern errno_t ext4_filesystem_get_inode_ref(ext4_filesystem_t *, uint32_t,
     ext4_inode_ref_t **);
-extern int ext4_filesystem_put_inode_ref(ext4_inode_ref_t *);
-extern int ext4_filesystem_alloc_inode(ext4_filesystem_t *, ext4_inode_ref_t **,
+extern errno_t ext4_filesystem_put_inode_ref(ext4_inode_ref_t *);
+extern errno_t ext4_filesystem_alloc_inode(ext4_filesystem_t *, ext4_inode_ref_t **,
     int);
-extern int ext4_filesystem_free_inode(ext4_inode_ref_t *);
-extern int ext4_filesystem_truncate_inode(ext4_inode_ref_t *, aoff64_t);
-extern int ext4_filesystem_get_inode_data_block_index(ext4_inode_ref_t *,
+extern errno_t ext4_filesystem_free_inode(ext4_inode_ref_t *);
+extern errno_t ext4_filesystem_truncate_inode(ext4_inode_ref_t *, aoff64_t);
+extern errno_t ext4_filesystem_get_inode_data_block_index(ext4_inode_ref_t *,
     aoff64_t iblock, uint32_t *);
-extern int ext4_filesystem_set_inode_data_block_index(ext4_inode_ref_t *,
+extern errno_t ext4_filesystem_set_inode_data_block_index(ext4_inode_ref_t *,
     aoff64_t, uint32_t);
-extern int ext4_filesystem_release_inode_block(ext4_inode_ref_t *, uint32_t);
-extern int ext4_filesystem_append_inode_block(ext4_inode_ref_t *, uint32_t *,
+extern errno_t ext4_filesystem_release_inode_block(ext4_inode_ref_t *, uint32_t);
+extern errno_t ext4_filesystem_append_inode_block(ext4_inode_ref_t *, uint32_t *,
     uint32_t *);
 uint32_t ext4_filesystem_bg_get_backup_blocks(ext4_block_group_ref_t *bg);
Index: uspace/lib/ext4/include/ext4/hash.h
===================================================================
--- uspace/lib/ext4/include/ext4/hash.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/hash.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -36,5 +36,5 @@
 #include "ext4/types.h"
 
-extern int ext4_hash_string(ext4_hash_info_t *, int, const char *);
+extern errno_t ext4_hash_string(ext4_hash_info_t *, int, const char *);
 
 #endif
Index: uspace/lib/ext4/include/ext4/ialloc.h
===================================================================
--- uspace/lib/ext4/include/ext4/ialloc.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/ialloc.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -36,6 +36,6 @@
 #include "ext4/types.h"
 
-extern int ext4_ialloc_free_inode(ext4_filesystem_t *, uint32_t, bool);
-extern int ext4_ialloc_alloc_inode(ext4_filesystem_t *, uint32_t *, bool);
+extern errno_t ext4_ialloc_free_inode(ext4_filesystem_t *, uint32_t, bool);
+extern errno_t ext4_ialloc_alloc_inode(ext4_filesystem_t *, uint32_t *, bool);
 
 #endif
Index: uspace/lib/ext4/include/ext4/inode.h
===================================================================
--- uspace/lib/ext4/include/ext4/inode.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/inode.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -59,5 +59,5 @@
 extern uint64_t ext4_inode_get_blocks_count(ext4_superblock_t *,
     ext4_inode_t *);
-extern int ext4_inode_set_blocks_count(ext4_superblock_t *, ext4_inode_t *,
+extern errno_t ext4_inode_set_blocks_count(ext4_superblock_t *, ext4_inode_t *,
     uint64_t);
 extern uint32_t ext4_inode_get_flags(ext4_inode_t *);
Index: uspace/lib/ext4/include/ext4/ops.h
===================================================================
--- uspace/lib/ext4/include/ext4/ops.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/ops.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -40,9 +40,9 @@
 extern libfs_ops_t ext4_libfs_ops;
 
-extern int ext4_global_init(void);
-extern int ext4_global_fini(void);
+extern errno_t ext4_global_init(void);
+extern errno_t ext4_global_fini(void);
 
-extern int ext4_node_get_core(fs_node_t **, ext4_instance_t *, fs_index_t);
-extern int ext4_node_put(fs_node_t *);
+extern errno_t ext4_node_get_core(fs_node_t **, ext4_instance_t *, fs_index_t);
+extern errno_t ext4_node_put(fs_node_t *);
 
 
Index: uspace/lib/ext4/include/ext4/superblock.h
===================================================================
--- uspace/lib/ext4/include/ext4/superblock.h	(revision 10de84286f36c6e4f3f92d59c073639668ffe9a1)
+++ uspace/lib/ext4/include/ext4/superblock.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
@@ -152,8 +152,8 @@
 extern bool ext4_superblock_has_feature_read_only(ext4_superblock_t *,
     uint32_t);
-extern int ext4_superblock_read_direct(service_id_t, ext4_superblock_t **);
-extern int ext4_superblock_write_direct(service_id_t, ext4_superblock_t *);
+extern errno_t ext4_superblock_read_direct(service_id_t, ext4_superblock_t **);
+extern errno_t ext4_superblock_write_direct(service_id_t, ext4_superblock_t *);
 extern void ext4_superblock_release(ext4_superblock_t *);
-extern int ext4_superblock_check_sanity(ext4_superblock_t *);
+extern errno_t ext4_superblock_check_sanity(ext4_superblock_t *);
 
 extern uint32_t ext4_superblock_get_block_group_count(ext4_superblock_t *);