fs: fat: export fat_next_cluster()

Rename function next_cluster() to fat_next_cluster() and export it.

When creating a new directory entries we should reuse deleted entries.
This requires re-scanning the directory.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

fs/fat/fat.c

@@ -621,7 +621,7 @@ static int get_fs_info(fsdata *mydata)
 		/*
 		 * The root directory is not cluster-aligned and may be on a
 		 * "negative" cluster, this will be handled specially in
-		 * next_cluster().
+		 * fat_next_cluster().
 		 */
 		mydata->root_cluster = 0;
 	}
@@ -647,44 +647,76 @@ static int get_fs_info(fsdata *mydata)
 	return 0;
 }
 
-
-/*
- * Directory iterator, to simplify filesystem traversal
+/**
+ * struct fat_itr - directory iterator, to simplify filesystem traversal
  *
  * Implements an iterator pattern to traverse directory tables,
  * transparently handling directory tables split across multiple
  * clusters, and the difference between FAT12/FAT16 root directory
  * (contiguous) and subdirectories + FAT32 root (chained).
  *
- * Rough usage:
+ * Rough usage
  *
- *   for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
- *      // to traverse down to a subdirectory pointed to by
- *      // current iterator position:
- *      fat_itr_child(&itr, &itr);
- *   }
+ * .. code-block:: c
  *
- * For more complete example, see fat_itr_resolve()
+ *     for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
+ *         // to traverse down to a subdirectory pointed to by
+ *         // current iterator position:
+ *         fat_itr_child(&itr, &itr);
+ *     }
+ *
+ * For a more complete example, see fat_itr_resolve().
  */
-
-typedef struct {
-	fsdata    *fsdata;        /* filesystem parameters */
-	unsigned   start_clust;   /* first cluster */
-	unsigned   clust;         /* current cluster */
-	unsigned   next_clust;    /* next cluster if remaining == 0 */
-	int        last_cluster;  /* set once we've read last cluster */
-	int        is_root;       /* is iterator at root directory */
-	int        remaining;     /* remaining dent's in current cluster */
-
-	/* current iterator position values: */
-	dir_entry *dent;          /* current directory entry */
-	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
-	char       s_name[14];    /* short 8.3 name */
-	char      *name;          /* l_name if there is one, else s_name */
-
-	/* storage for current cluster in memory: */
-	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
-} fat_itr;
+struct fat_itr {
+	/**
+	 * @fsdata:		filesystem parameters
+	 */
+	fsdata *fsdata;
+	/**
+	 * @start_clust:	first cluster
+	 */
+	unsigned int start_clust;
+	/**
+	 * @clust:		current cluster
+	 */
+	unsigned int clust;
+	/**
+	 * @next_clust:		next cluster if remaining == 0
+	 */
+	unsigned int next_clust;
+	/**
+	 * @last_cluster:	set if last cluster of directory reached
+	 */
+	int last_cluster;
+	/**
+	 * @is_root:		is iterator at root directory
+	 */
+	int is_root;
+	/**
+	 * @remaining:		remaining directory entries in current cluster
+	 */
+	int remaining;
+	/**
+	 * @dent:		current directory entry
+	 */
+	dir_entry *dent;
+	/**
+	 * @l_name:		long name of current directory entry
+	 */
+	char l_name[VFAT_MAXLEN_BYTES];
+	/**
+	 * @s_name:		short 8.3 name of current directory entry
+	 */
+	char s_name[14];
+	/**
+	 * @name:		l_name if there is one, else s_name
+	 */
+	char *name;
+	/**
+	 * @block:		buffer for current cluster
+	 */
+	u8 block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+};
 
 static int fat_itr_isdir(fat_itr *itr);
 
@@ -753,7 +785,17 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 	itr->last_cluster = 0;
 }
 
-static void *next_cluster(fat_itr *itr, unsigned *nbytes)
+/**
+ * fat_next_cluster() - load next FAT cluster
+ *
+ * The function is used when iterating through directories. It loads the
+ * next cluster with directory entries
+ *
+ * @itr:	directory iterator
+ * @nbytes:	number of bytes read, 0 on error
+ * Return:	first directory entry, NULL on error
+ */
+void *fat_next_cluster(fat_itr *itr, unsigned int *nbytes)
 {
 	fsdata *mydata = itr->fsdata;  /* for silly macros */
 	int ret;
@@ -825,7 +867,7 @@ static dir_entry *next_dent(fat_itr *itr)
 {
 	if (itr->remaining == 0) {
 		unsigned nbytes;
-		struct dir_entry *dent = next_cluster(itr, &nbytes);
+		struct dir_entry *dent = fat_next_cluster(itr, &nbytes);
 
 		/* have we reached the last cluster? */
 		if (!dent) {

include/fat.h

@@ -9,8 +9,9 @@
 #ifndef _FAT_H_
 #define _FAT_H_
 
-#include <asm/byteorder.h>
 #include <fs.h>
+#include <asm/byteorder.h>
+#include <asm/cache.h>
 
 struct disk_partition;
 
@@ -179,6 +180,9 @@ typedef struct {
 	int	fats;		/* Number of FATs */
 } fsdata;
 
+struct fat_itr;
+typedef struct fat_itr fat_itr;
+
 static inline u32 clust_to_sect(fsdata *fsdata, u32 clust)
 {
 	return fsdata->data_begin + clust * fsdata->clust_size;
@@ -208,4 +212,5 @@ void fat_closedir(struct fs_dir_stream *dirs);
 int fat_unlink(const char *filename);
 int fat_mkdir(const char *dirname);
 void fat_close(void);
+void *fat_next_cluster(fat_itr *itr, unsigned int *nbytes);
 #endif /* _FAT_H_ */