More NXFFS logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3538 42af7a65-404d-4744-a932-0658087f49c3

fs/nxffs/Make.defs

@@ -35,9 +35,9 @@
 
 ifeq ($(CONFIG_FS_NXFFS),y)
 ASRCS +=
-CSRCS += nxffs_block.c nxffs_blockstats.c nxffs_cache.c \
+CSRCS += nxffs_block.c nxffs_blockstats.c nxffs_cache.c nxffs_dirent.c \
-		 nxffs_initialize.c nxffs_inode.c nxffs_open.c nxffs_reformat.c \
+		 nxffs_initialize.c nxffs_inode.c nxffs_ioctl.c nxffs_open.c \
-		 nxffs_stat.c nxffs_unlink.c nxffs_util.c
+		 nxffs_reformat.c nxffs_stat.c nxffs_unlink.c nxffs_util.c
 
 # Argument for dependency checking
 

fs/nxffs/README.txt

@@ -0,0 +1,94 @@
+General NXFFS organization
+==========================
+
+The following example assumes 4 logical blocks per FLASH erase block.  The
+actual relationship is determined by the FLASH geometry reported by the MTD
+driver.
+
+ERASE LOGICAL                   Inodes begin with a inode header.  inode may
+BLOCK BLOCK       CONTENTS      be marked as "deleted," pending clean-up.
+  n   4*n     --+--------------+
+                |BBBBBBBBBBBBBB| Logic block header
+                |IIIIIIIIIIIIII| Inodes begin with a inode header
+                |DDDDDDDDDDDDDD| Data block containing inode data block
+                | (Inode Data) |
+      4*n+1   --+--------------+
+                |BBBBBBBBBBBBBB| Logic block header
+                |DDDDDDDDDDDDDD| Inodes may consist of multiple data blocks
+                | (Inode Data) |
+                |IIIIIIIIIIIIII| Next inode header
+                |              | Possibly a few unused bytes at the end of a block
+      4*n+2   --+--------------+
+                |BBBBBBBBBBBBBB| Logic block header
+                |DDDDDDDDDDDDDD|
+                | (Inode Data) |
+      4*n+3   --+--------------+
+                |BBBBBBBBBBBBBB| Logic block header
+                |IIIIIIIIIIIIII| Next inode header
+                |DDDDDDDDDDDDDD|
+                | (Inode Data) |
+ n+1  4*(n+1) --+--------------+
+                |BBBBBBBBBBBBBB| Logic block header
+                |              | All FLASH is unused after the end of the final
+                |              | inode.
+              --+--------------+
+
+General operation
+=================
+
+  Inodes are written starting at the beginning of FLASH.  As inodes are
+  deleted, they are marked as deleted but not removed.  As new inodes are
+  written, allocations  proceed to toward the end of the FLASH -- thus,
+  supporting wear leveling by using all FLASH blocks equally.
+
+  When the FLASH becomes full (no more space at the end of the FLASH), a
+  clean-up operation must be performed:  All inodes marked deleted are
+  finally removed and the remaining inodes are packed at the beginning of
+  the FLASH.  Allocations then continue at the freed FLASH memory at the
+  end of the FLASH.
+
+Headers
+=======
+  BLOCK HEADER:
+    The block header is used to determine if the block has every been
+    formatted and also indicates bad blocks which should never be used.
+
+  INODE HEADER:
+    Each inode begins with an inode header that contains, among other things,
+    the name of the inode, the offset to the first data block, and the
+    length of the inode data.
+
+    At present, the only kind of inode support is a file.  So for now, the
+    term file and inode are interchangeable.
+
+  INODE DATA HEADER:
+    Inode data is enclosed in a data header.  For a given inode, there
+    is at most one inode data block per logical block.  If the inode data
+    spans more than one logical block, then the inode data may be enclosed
+    in multiple data blocks, one per logical block.
+
+NXFFS Limitations
+=================
+
+This implementation is very simple as, as a result, has several limitations
+that you should be aware before opting to use NXFFS:
+
+1. Since the files are contiguous in FLASH and since allocations always
+   proceed toward the end of the FLASH, there can only be one file opened
+   for writing at a time.  Multiple files may be opened for reading.
+
+2. Files may not be increased in size after they have been closed.  The
+   O_APPEND open flag is not supported.
+
+3. Files are always written sequential.  Seeking within a file opened for
+   writing will not work.
+
+4. There are no directories, however, '/' may be used within a file name
+   string providing some illusion of directories.
+
+5. Files may be opened for reading or for writing, but not both: The O_RDWR
+   open flag is not supported.
+
+6. The clean-up process occurs only during a write when the free FLASH
+   memory at the end of the FLASH is exhausted.  Thus, occasionally, file
+   writing may take a long time.

fs/nxffs/nxffs.h

@@ -73,14 +73,14 @@
  *   n   4*n     --+--------------+
  *                 |BBBBBBBBBBBBBB| Logic block header
  *                 |IIIIIIIIIIIIII| Inodes begin with a inode header
- *                 |DDDDDDDDDDDDD| Data block containing inode data block
+ *                 |DDDDDDDDDDDDDD| Data block containing inode data block
  *                 | (Inode Data) |
  *       4*n+1   --+--------------+
  *                 |BBBBBBBBBBBBBB| Logic block header
  *                 |DDDDDDDDDDDDDD| Inodes may consist of multiple data blocks
  *                 | (Inode Data) |
  *                 |IIIIIIIIIIIIII| Next inode header
- *                 |             | Possibly a few unused bytes at the end of a block
+ *                 |              | Possibly a few unused bytes at the end of a block
  *       4*n+2   --+--------------+
  *                 |BBBBBBBBBBBBBB| Logic block header
  *                 |DDDDDDDDDDDDDD|
@@ -141,7 +141,6 @@
  * 6. The clean-up process occurs only during a write when the free FLASH
  *    memory at the end of the FLASH is exhausted.  Thus, occasionally, file
  *    writing may take a long time.
- *
  */
 
 /* Values for logical block state.  Basically, there are only two, perhaps
@@ -703,7 +702,7 @@ extern int nxffs_rminode(FAR struct nxffs_volume_s *volume, FAR const char *name
  * - nxffs_open() and nxffs_close() are defined in nxffs_open.c
  * - nxffs_ioctl() is defined in nxffs_ioctl.c
  * - nxffs_opendir(), nxffs_readdir(), and nxffs_rewindir() are defined in
- *   nxffs_dir.c
+ *   nxffs_dirent.c
  * - nxffs_stat() and nxffs_statfs() are defined in nxffs_stat.c
  * - nxffs_unlink() is defined nxffs_unlink.c
  *

fs/nxffs/nxffs_dirent.c

@@ -0,0 +1,222 @@
+/****************************************************************************
+ * fs/nxffs/nxffs_dirent.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * References: Linux/Documentation/filesystems/romfs.txt
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <string.h>
+#include <dirent.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/fs.h>
+#include <nuttx/mtd.h>
+#include <nuttx/dirent.h>
+
+#include "nxffs.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxffs_opendir
+ *
+ * Description:
+ *   Open a directory for read access
+ *
+ ****************************************************************************/
+
+int nxffs_opendir(FAR struct inode *mountpt, FAR const char *relpath,
+                  FAR struct fs_dirent_s *dir)
+{
+  struct nxffs_volume_s *volume;
+  int ret;
+
+  fvdbg("relpath: \"%s\"\n", relpath ? relpath : "NULL");
+
+  /* Sanity checks */
+
+  DEBUGASSERT(mountpt != NULL && mountpt->i_private != NULL);
+
+  /* Recover the file system state from the NuttX inode instance */
+
+  volume = mountpt->i_private;
+  ret = sem_wait(&volume->exclsem);
+  if (ret != OK)
+    {
+      goto errout;
+    }
+
+  /* The requested directory must be the volume-relative "root" directory */
+
+  if (relpath && relpath[0] != '\0')
+    {
+      ret = -ENOENT;
+      goto errout_with_semaphore;
+    }
+
+  /* Set the offset to the offset to the first valid inode */
+
+  dir->u.nxffs.nx_offset = volume->inoffset;
+  ret = OK;
+
+errout_with_semaphore:
+  sem_post(&volume->exclsem);
+errout:
+  return ret;
+}
+
+/****************************************************************************
+ * Name: nxffs_readdir
+ *
+ * Description: Read the next directory entry
+ *
+ ****************************************************************************/
+
+int nxffs_readdir(FAR struct inode *mountpt, FAR struct fs_dirent_s *dir)
+{
+  FAR struct nxffs_volume_s *volume;
+  FAR struct nxffs_entry_s entry;
+  off_t offset;
+  int ret;
+
+  /* Sanity checks */
+
+  DEBUGASSERT(mountpt != NULL && mountpt->i_private != NULL);
+
+  /* Recover the file system state from the NuttX inode instance */
+
+  volume = mountpt->i_private;
+  ret = sem_wait(&volume->exclsem);
+  if (ret != OK)
+    {
+      goto errout;
+    }
+
+  /* Read the next inode header from the offset */
+
+  offset = dir->u.nxffs.nx_offset;
+  ret = nxffs_nextentry(volume, offset, &entry);
+
+  /* If the read was successful, then handle the reported inode.  Note
+   * that when the last inode has been reported, the value -ENOENT will
+   * be returned.. which is correct for the readdir() method.
+   */
+
+  if (ret == OK)
+    {
+      /* Return the filename and file type */
+
+      fvdbg("Offset %d: \"%s\"\n", entry.hoffset, entry.name);
+      dir->fd_dir.d_type = DTYPE_FILE;
+      strncpy(dir->fd_dir.d_name, entry.name, NAME_MAX+1);
+
+      /* Discard this entry and set the next offset using the rw data
+       * length as the offset increment.  This is, of course, not accurate
+       * because it does not account for the data headers that enclose the
+       * data.  But it is guaranteed to be less than or equal to the
+       * correct offset and, hence, better then searching byte-for-byte.
+       */
+
+      dir->u.nxffs.nx_offset = entry.doffset + entry.datlen;
+      nxffs_freeentry(&entry);
+      ret = OK;
+    }
+
+  sem_post(&volume->exclsem);
+errout:
+  return ret;
+}
+
+/****************************************************************************
+ * Name: nxffs_rewindir
+ *
+ * Description:
+ *   Reset directory read to the first entry
+ *
+ ****************************************************************************/
+
+int nxffs_rewinddir(FAR struct inode *mountpt, FAR struct fs_dirent_s *dir)
+{
+  FAR struct nxffs_volume_s *volume;
+  int ret;
+
+  fvdbg("Entry\n");
+
+  /* Sanity checks */
+
+  DEBUGASSERT(mountpt != NULL && mountpt->i_private != NULL);
+
+  /* Recover the file system state from the NuttX inode instance */
+
+  volume = mountpt->i_private;
+  ret = sem_wait(&volume->exclsem);
+  if (ret != OK)
+    {
+      goto errout;
+    }
+
+  /* Reset the offset to the FLASH offset to the first valid inode */
+
+  dir->u.nxffs.nx_offset = volume->inoffset;
+  ret = OK;
+
+  sem_post(&volume->exclsem);
+errout:
+  return ret;
+}

fs/nxffs/nxffs_ioctl.c

@@ -0,0 +1,100 @@
+/****************************************************************************
+ * fs/nxffs/nxffs_ioctl.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * References: Linux/Documentation/filesystems/romfs.txt
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/fs.h>
+#include <nuttx/mtd.h>
+
+#include "nxffs.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxffs_ioctl
+ *
+ * Description:
+ *   Standard mountpoint ioctl method.
+ *
+ ****************************************************************************/
+
+int nxffs_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
+{
+  FAR struct nxffs_volume_s *volume;
+
+  fvdbg("cmd: %d arg: %08lx\n", cmd, arg);
+
+  /* Sanity checks */
+
+  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);
+
+  /* Recover the file system state from the open file */
+
+  volume = filep->f_inode->i_private;
+  DEBUGASSERT(volume != NULL);
+
+  /* No ioctl commands yet supported */
+
+  return -ENOTTY;
+}

fs/nxffs/nxffs_open.c

@@ -289,6 +289,10 @@ static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
 
 /****************************************************************************
  * Name: nxffs_freeofile
+ *
+ * Description:
+ *   Free resources held by an open file.
+ *
  ****************************************************************************/
 
 static inline void nxffs_freeofile(FAR struct nxffs_ofile_s *ofile)

include/nuttx/dirent.h

@@ -105,6 +105,17 @@ struct fs_binfsdir_s
   unsigned int fb_index;               /* Index to the next named entry point */
 };
 #endif
+
+#ifdef CONFIG_FS_NXFFS
+/* NXFFS is the tiny NuttX wear-leveling FLASH file system.  The state value is
+ * the offset in FLASH memory to the next inode entry.
+ */
+
+struct fs_nxffsdir_s
+{
+  off_t nx_offset;                     /* Offset to the next inode */
+};
+#endif
 #endif /* CONFIG_DISABLE_MOUNTPOINT */
 
 struct fs_dirent_s
@@ -153,7 +164,10 @@ struct fs_dirent_s
 #ifdef CONFIG_APPS_BINDIR
       struct fs_binfsdir_s  binfs;
 #endif
+#ifdef CONFIG_FS_NXFFS
+      struct fs_nxffsdir_s  nxffs;
 #endif
+#endif /* !CONFIG_DISABLE_MOUNTPOINT */
    } u;
 
   /* In any event, this the actual struct dirent that is returned by readdir */