Implement file lastblock caching in flash

This change stores the last written block for each file in the metadata
stored in flash. It facilitates restoring and mounting the filesystem
during initialization by removing the requirement to search every block in
flash to find the last block of each file.

This change requires the previous commit changing the on-flash data structures
which include a reference to the lastblock. This change is not backwards
compatible with previous on-flash version of NFFS, and there is a check
to make sure that the current version is used. Users upgrading to this version
of NFFS will need to reformat their flash devices - currently there is no
facility for in-place upgrades of existing filesystems.

One side-effect of this change is that inode updates are written to flash
each time a new block is added to the file. Other changes include additional
state flags with checking to provide additional resilience with minimal
space and compute overhead. There is also additional debugging tools in
nffs_test.c.

1 files changed, 34 insertions, 36 deletions

diff --git a/fs/nffs/src/nffs_priv.h b/fs/nffs/src/nffs_priv.h
index 76c78276..b654b85b 100644
--- a/fs/nffs/src/nffs_priv.h
+++ b/fs/nffs/src/nffs_priv.h
@@ -39,6 +39,7 @@
 
 #define NFFS_ID_ROOT_DIR             0
 #define NFFS_ID_NONE                 0xffffffff
+#define NFFS_HASH_ENTRY_NONE         0xffffffff
 
 #define NFFS_AREA_MAGIC0             0xb98a31e2
 #define NFFS_AREA_MAGIC1             0x7fb0428c
@@ -48,7 +49,7 @@
 #define NFFS_INODE_MAGIC             0x925f8bc0
 
 #define NFFS_AREA_ID_NONE            0xff
-#define NFFS_AREA_VER_0				 0
+#define NFFS_AREA_VER_0                 0
 #define NFFS_AREA_VER_1              1
 #define NFFS_AREA_VER                NFFS_AREA_VER_1
 #define NFFS_AREA_OFFSET_ID          23
@@ -68,44 +69,14 @@ struct nffs_disk_area {
 };
 
 /** On-disk representation of an inode (file or directory). */
-struct nffs_disk_inodeV0 {
-    uint32_t ndi_magic;         /* NFFS_INODE_MAGIC */
-    uint32_t ndi_id;            /* Unique object ID. */
-    uint32_t ndi_seq;           /* Sequence number; greater supersedes
-                                   lesser. */
-    uint32_t ndi_parent_id;     /* Object ID of parent directory inode. */
-    uint8_t reserved8;
-    uint8_t ndi_filename_len;   /* Length of filename, in bytes. */
-    uint16_t ndi_crc16;         /* Covers rest of header and filename. */
-    /* Followed by filename. */
-};
-
-#define NFFS_DISK_INODEV0_OFFSET_CRC  18
-
-/** On-disk representation of a data block. */
-struct nffs_disk_blockV0 {
-    uint32_t ndb_magic;     /* NFFS_BLOCK_MAGIC */
-    uint32_t ndb_id;        /* Unique object ID. */
-    uint32_t ndb_seq;       /* Sequence number; greater supersedes lesser. */
-    uint32_t ndb_inode_id;  /* Object ID of owning inode. */
-    uint32_t ndb_prev_id;   /* Object ID of previous block in file;
-                               NFFS_ID_NONE if this is the first block. */
-    uint16_t ndb_data_len;  /* Length of data contents, in bytes. */
-    uint16_t ndb_crc16;     /* Covers rest of header and data. */
-    /* Followed by 'ndb_data_len' bytes of data. */
-};
-
-#define NFFS_DISK_BLOCKV0_OFFSET_CRC  22
-
-/** On-disk representation of an inode (file or directory). */
 struct nffs_disk_inode {
     uint32_t ndi_id;            /* Unique object ID. */
     uint32_t ndi_parent_id;     /* Object ID of parent directory inode. */
     uint32_t ndi_lastblock_id;     /* Object ID of parent directory inode. */
     uint16_t ndi_seq;           /* Sequence number; greater supersedes
                                    lesser. */
-	uint16_t reserved16;
-    uint8_t reserved8;
+    uint16_t reserved16;
+    uint8_t ndi_flags;            /* flags */
     uint8_t ndi_filename_len;   /* Length of filename, in bytes. */
     uint16_t ndi_crc16;         /* Covers rest of header and filename. */
     /* Followed by filename. */
@@ -149,10 +120,26 @@ struct nffs_inode_entry {
     union {
         struct nffs_inode_list nie_child_list;           /* If directory */
         struct nffs_hash_entry *nie_last_block_entry;    /* If file */
+        uint32_t nie_lastblock_id;
     };
     uint8_t nie_refcnt;
+    uint8_t nie_flags;
+    uint16_t reserved16;
 };
 
+#define    NFFS_INODE_FLAG_FREE        0x00
+#define    NFFS_INODE_FLAG_DUMMY       0x01    /* inode is a dummy */
+#define    NFFS_INODE_FLAG_DUMMYPARENT 0x02    /* parent not in cache */
+#define    NFFS_INODE_FLAG_DUMMYLSTBLK 0x04    /* lastblock not in cache */
+#define    NFFS_INODE_FLAG_DUMMYINOBLK 0x08    /* dummy inode for blk */
+#define    NFFS_INODE_FLAG_OBSOLETE    0x10    /* always replace if same ID */
+#define    NFFS_INODE_FLAG_INTREE      0x20    /* in directory structure */
+#define    NFFS_INODE_FLAG_INHASH      0x40    /* in hash table */
+#define    NFFS_INODE_FLAG_DELETED     0x80    /* inode deleted */
+
+#define nie_id            nie_hash_entry.nhe_id
+#define nie_flash_loc    nie_hash_entry.nhe_flash_loc
+
 /** Full inode representation; not stored permanently RAM. */
 struct nffs_inode {
     struct nffs_inode_entry *ni_inode_entry; /* Points to real inode entry. */
@@ -199,8 +186,8 @@ struct nffs_disk_object {
     } ndo_un_obj;
 };
 
-#define ndo_disk_inode	ndo_un_obj.ndo_disk_inode
-#define ndo_disk_block	ndo_un_obj.ndo_disk_block
+#define ndo_disk_inode    ndo_un_obj.ndo_disk_inode
+#define ndo_disk_block    ndo_un_obj.ndo_disk_block
 
 struct nffs_seek_info {
     struct nffs_block nsi_last_block;
@@ -269,6 +256,7 @@ extern uint8_t nffs_num_areas;
 extern uint8_t nffs_scratch_area_idx;
 extern uint16_t nffs_block_max_data_sz;
 extern unsigned int nffs_gc_count;
+extern struct nffs_area_desc *nffs_current_area_descs;
 
 #define NFFS_FLASH_BUF_SZ        256
 extern uint8_t nffs_flash_buf[NFFS_FLASH_BUF_SZ];
@@ -313,6 +301,7 @@ int nffs_block_from_hash_entry(struct nffs_block *out_block,
                                struct nffs_hash_entry *entry);
 int nffs_block_read_data(const struct nffs_block *block, uint16_t offset,
                          uint16_t length, void *dst);
+int nffs_block_is_dummy(struct nffs_hash_entry *entry);
 
 /* @cache */
 void nffs_cache_inode_delete(const struct nffs_inode_entry *inode_entry);
@@ -390,6 +379,8 @@ struct nffs_hash_entry *nffs_hash_find_block(uint32_t id);
 void nffs_hash_insert(struct nffs_hash_entry *entry);
 void nffs_hash_remove(struct nffs_hash_entry *entry);
 int nffs_hash_init(void);
+int nffs_hash_entry_is_dummy(struct nffs_hash_entry *he);
+int nffs_hash_id_is_dummy(uint32_t id);
 
 /* @inode */
 struct nffs_inode_entry *nffs_inode_entry_alloc(void);
@@ -407,6 +398,7 @@ int nffs_inode_entry_from_disk(struct nffs_inode_entry *out_inode,
 int nffs_inode_rename(struct nffs_inode_entry *inode_entry,
                       struct nffs_inode_entry *new_parent,
                       const char *new_filename);
+int nffs_inode_update(struct nffs_inode_entry *inode_entry);
 void nffs_inode_insert_block(struct nffs_inode *inode,
                              struct nffs_block *block);
 int nffs_inode_read_disk(uint8_t area_idx, uint32_t offset,
@@ -414,6 +406,7 @@ int nffs_inode_read_disk(uint8_t area_idx, uint32_t offset,
 int nffs_inode_write_disk(const struct nffs_disk_inode *disk_inode,
                           const char *filename, uint8_t area_idx,
                           uint32_t offset);
+int nffs_inode_inc_refcnt(struct nffs_inode_entry *inode_entry);
 int nffs_inode_dec_refcnt(struct nffs_inode_entry *inode_entry);
 int nffs_inode_add_child(struct nffs_inode_entry *parent,
                          struct nffs_inode_entry *child);
@@ -439,6 +432,11 @@ int nffs_inode_unlink_from_ram(struct nffs_inode *inode,
 int nffs_inode_unlink_from_ram_corrupt_ok(struct nffs_inode *inode,
                                           struct nffs_hash_entry **out_next);
 int nffs_inode_unlink(struct nffs_inode *inode);
+int nffs_inode_is_dummy(struct nffs_inode_entry *inode_entry);
+int nffs_inode_is_deleted(struct nffs_inode_entry *inode_entry);
+int nffs_inode_setflags(struct nffs_inode_entry *entry, uint8_t flag);
+int nffs_inode_unsetflags(struct nffs_inode_entry *entry, uint8_t flag);
+int nffs_inode_getflags(struct nffs_inode_entry *entry, uint8_t flag);
 
 /* @misc */
 int nffs_misc_gc_if_oom(void *resource, int *out_rc);
@@ -483,7 +481,7 @@ int nffs_write_to_file(struct nffs_file *file, const void *data, int len);
 #ifdef NFFS_DEBUG
 #include <stdio.h>
 #define NFFS_LOG(lvl, ...) \
-  	printf(__VA_ARGS__)
+      printf(__VA_ARGS__)
 #else
 #define NFFS_LOG(lvl, ...) \
     LOG_ ## lvl(&nffs_log, LOG_MODULE_NFFS, __VA_ARGS__)