add filemap

we can use filemap to dump file real extents info. Ex,

0:      0000000000000000 0000000193480000 0000000000001000 0000
1:      0000000000002000 0000000193482000 0000000000001000 0000
2:      0000000000004000 0000000193484000 0000000000001000 0000
3:      0000000000006000 0000000193486000 0000000000001000 0000
4:      0000000000008000 0000000193488000 0000000000001000 0000
5:      000000000000a000 000000019348a000 0000000000001000 0000
6:      000000000000c000 000000019348c000 0000000000001000 0000
7:      000000000000e000 000000019348e000 0000000000001000 0000
8:      0000000000010000 0000000193490000 0000000000001000 0000
9:      0000000000012000 0000000193492000 0000000000001000 0000
10:     0000000000014000 0000000193494000 0000000000001000 0000
11:     0000000000016000 0000000193496000 0000000000001000 0000
12:     0000000000018000 0000000193498000 0000000000001000 0000

Signed-off-by: zhenwei pi <p_ace@126.com>

Makefile

@@ -5,10 +5,11 @@ GETTIMEOFDAY=gettimeofday
 GETALLCHANGELOG=get-all-changelog.py
 OBJDUMPFUNCTION=objdump-function.sh
 SPARSEFILE=sparse-file
+FILEMAP=filemap
 
-.PHONY : $(DTOH) $(HTOD) $(CTIME) $(GETTIMEOFDAY) $(SPARSEFILE)
+.PHONY : $(DTOH) $(HTOD) $(CTIME) $(GETTIMEOFDAY) $(SPARSEFILE) $(FILEMAP)
 
-all : $(DTOH) $(HTOD) $(CTIME) $(GETTIMEOFDAY) $(SPARSEFILE)
+all : $(DTOH) $(HTOD) $(CTIME) $(GETTIMEOFDAY) $(SPARSEFILE) $(FILEMAP)
 
 $(DTOH) :
 	gcc $(DTOH).c -O2 -o $(DTOH)
@@ -25,6 +26,9 @@ $(GETTIMEOFDAY) :
 $(SPARSEFILE) :
 	gcc $(SPARSEFILE).c -O2 -o $(SPARSEFILE)
 
+$(FILEMAP) :
+	gcc $(FILEMAP).c -O2 -o $(FILEMAP)
+
 install :
 	@sudo cp $(DTOH) /usr/bin
 	@sudo cp $(HTOD) /usr/bin
@@ -33,6 +37,7 @@ install :
 	@sudo cp $(GETALLCHANGELOG) /usr/bin
 	@sudo cp $(OBJDUMPFUNCTION) /usr/bin
 	@sudo cp $(SPARSEFILE) /usr/bin
+	@sudo cp $(FILEMAP) /usr/bin
 
 clean :
 	@rm -rf $(DTOH)
@@ -42,3 +47,4 @@ clean :
 	@rm -rf $(GETALLCHANGELOG)
 	@rm -rf $(OBJDUMPFUNCTION)
 	@rm -rf $(SPARSEFILE)
+	@rm -rf $(FILEMAP)

README.md

@@ -26,3 +26,6 @@ RUN
 >
 >sparse-file : generate sparse file
 >       Ex, sparse-file -s 4096 -t 409600000
+>
+>filemap : dump file extents, logical address, physical address mapping info.
+>       Ex, filemap test.file

filemap.c

@@ -0,0 +1,114 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <linux/fiemap.h>
+#include <linux/fs.h>
+
+#ifndef FS_IOC_FIEMAP
+#define FS_IOC_FIEMAP	_IOWR('f', 11, struct fiemap)
+#endif
+
+void usage(char **argv)
+{
+	fprintf(stderr, "%s [filename] ...\n", argv[0]);
+}
+
+struct fiemap *read_fiemap(int fd)
+{
+	struct fiemap *fiemap;
+	int extents_size;
+
+	if ((fiemap = (struct fiemap*)malloc(sizeof(struct fiemap))) == NULL) {
+		fprintf(stderr, "malloc\n");	
+		return NULL;
+	}
+
+	memset(fiemap, 0, sizeof(struct fiemap));
+
+	fiemap->fm_start = 0;
+	fiemap->fm_length = ~0;
+	fiemap->fm_flags = 0;
+	fiemap->fm_extent_count = 0;
+	fiemap->fm_mapped_extents = 0;
+
+	/* count how many extents there are */
+	if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) {
+		fprintf(stderr, "fiemap ioctl() failed\n");
+		return NULL;
+	}
+
+	/* read in the extents */
+	extents_size = sizeof(struct fiemap_extent) * 
+		(fiemap->fm_mapped_extents);
+
+	/* resize fiemaps for all extents */
+	if ((fiemap = (struct fiemap*)realloc(fiemap,sizeof(struct fiemap) + 
+					extents_size)) == NULL) {
+		fprintf(stderr, "realloc fiemap\n");	
+		return NULL;
+	}
+
+	memset(fiemap->fm_extents, 0, extents_size);
+	fiemap->fm_extent_count = fiemap->fm_mapped_extents;
+	fiemap->fm_mapped_extents = 0;
+
+	if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) {
+		fprintf(stderr, "ioctl() FS_IOC_FIEMAP failed\n");
+		return NULL;
+	}
+
+	return fiemap;
+}
+
+void show_fiemap(struct fiemap *fiemap, char *filename)
+{
+	int i = 0;
+
+	printf("File %s has %d extents :\n", filename, fiemap->fm_mapped_extents);
+	printf("#\tLogical          Physical         Length           Flag\n");
+	for (i = 0; i < fiemap->fm_mapped_extents; i++) {
+		printf("%d:\t%-16.16llx %-16.16llx %-16.16llx %-4.4x\n", i,
+				fiemap->fm_extents[i].fe_logical,
+				fiemap->fm_extents[i].fe_physical,
+				fiemap->fm_extents[i].fe_length,
+				fiemap->fm_extents[i].fe_flags);
+	}
+
+	printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+	int i = 0;
+
+	if (argc < 2) {
+		usage(argv);
+		return 0;
+	}
+
+	for (i = 1; i < argc; i++) {
+		int fd = 0;
+
+		if ((fd = open(argv[i], O_RDONLY)) < 0) {
+			perror("open file %s failed\n");
+			perror(argv[i]);
+			break;
+		} else {
+			struct fiemap *fiemap = NULL;
+
+			if ((fiemap = read_fiemap(fd)) != NULL) {
+				show_fiemap(fiemap, argv[i]);
+				free(fiemap);
+			}
+			close(fd);
+		}
+	}
+
+	return 0;
+}
+