From: NeilBrown <neilb@suse.de>
Date: Wed, 2 Mar 2011 23:39:26 +0000 (+1100)
Subject: mkfs: allow creation of a filesystem on a regular file.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=254c17e5d95a2b8d2ef9706a6024e772bd6bafdd;p=lafs-utils.git

mkfs: allow creation of a filesystem on a regular file.

Primarily for ease of testing.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/lib/lafs_add_device.c b/lib/lafs_add_device.c
index 6e8a683..3f5e702 100644
--- a/lib/lafs_add_device.c
+++ b/lib/lafs_add_device.c
@@ -1,3 +1,5 @@
+#define _GNU_SOURCE
+#define _FILE_OFFSET_BITS 64
 
 #include <unistd.h>
 #include <lafs/lafs.h>
@@ -28,6 +30,8 @@ static int get_logical_block_size(int fd)
 	char path[60];
 	char buf[20];
 	fstat(fd, &stb);
+	if ((stb.st_mode & S_IFMT) != S_IFBLK)
+		return 512;
 	sprintf(path, "/sys/dev/block/%d:%d/queue/logical_block_size",
 		major(stb.st_rdev), minor(stb.st_rdev));
 	sfd = open(path, O_RDONLY);
@@ -89,7 +93,8 @@ struct lafs_device *lafs_add_device(struct lafs *fs, char *devname, int fd,
 	 * Device block needs 1K and goes once at start and once at end.
 	 * Start location is 1K in unless basic block size is larger
 	 */
-	ioctl(fd, BLKGETSIZE64, &size);
+	if (ioctl(fd, BLKGETSIZE64, &size) < 0)
+		size = lseek64(fd, 0, SEEK_END);
 	devblk = get_logical_block_size(fd);
 	if (devblk < LAFS_DEVBLK_SIZE)
 		devblk = LAFS_DEVBLK_SIZE;
diff --git a/tools/mkfs.lafs.c b/tools/mkfs.lafs.c
index 40565f0..d24ee44 100644
--- a/tools/mkfs.lafs.c
+++ b/tools/mkfs.lafs.c
@@ -62,6 +62,7 @@ enum {
 	opt_width,
 	opt_stride,
 	opt_noatime,
+	opt_regular,
 };
 
 char short_options[] = "-b:Vvh";
@@ -74,6 +75,7 @@ struct option long_options[] = {
 	{"verbose",      0, 0, 'v'},
 	{"help",         0, 0, 'h'},
 	{"no-atime-file",0, 0, opt_noatime},
+	{"regular-file", 0, 0, opt_regular},
 	{0, 0, 0, 0}
 };
 
@@ -255,27 +257,39 @@ void validate_parameters(long *block_bytes, long *segment_bytes, long *stride_by
 	}
 }
 
-int open_device(char *devname, long long *device_bytes)
+int open_device(char *devname, long long *device_bytes, int regular_file)
 {
 	/* must be able to get an exclusive open on the device and its size
 	 * must be non-trivial
-	 *
+	 * If 'regular_file', then expect a regular file to be used instead.
 	 */
 	int fd;
 	struct stat stb;
-	unsigned long long size;
+	unsigned long long size = 0;
 
 	fd = open(devname, O_RDWR|O_EXCL);
-	if (fd < 0)
+	if (fd < 0 || fstat(fd, &stb) < 0) {
 		fprintf(stderr, "mkfs.lafs: cannot open device %s: %s\n",
 			devname, strerror(errno));
-	else if (fstat(fd, &stb) < 0 ||
-		 (stb.st_mode & S_IFMT) != S_IFBLK)
-		fprintf(stderr, "mkfs.lafs: %s is not a block device\n",
-			devname);
-	else if (ioctl(fd, BLKGETSIZE64, &size) != 0)
-		fprintf(stderr, "mkfs.lafs: Cannot get size of %s\n",
-			devname);
+		exit(2);
+	}
+
+	if (regular_file) {
+		if ((stb.st_mode & S_IFMT) != S_IFREG)
+			fprintf(stderr, "mkfs.lafs: %s is not a regular file\n",
+				devname);
+		else
+			size = stb.st_size;
+	} else {
+		if ((stb.st_mode & S_IFMT) != S_IFBLK)
+			fprintf(stderr, "mkfs.lafs: %s is not a block device\n",
+				devname);
+		else if (ioctl(fd, BLKGETSIZE64, &size) != 0)
+			fprintf(stderr, "mkfs.lafs: Cannot get size of %s\n",
+				devname);
+	}
+	if (size == 0)
+		;
 	else if (size < 64*1024)
 		fprintf(stderr, "mkfs.lafs: %s is too small for a LAFS filesystem\n",
 			devname);
@@ -296,6 +310,7 @@ int main(int argc, char *argv[])
 	long long device_bytes;
 	char *devname = NULL;
 	int create_atime = 1;
+	int regular_file = 0;
 	int opt;
 	int dev_fd;
 	struct lafs *lafs;
@@ -332,6 +347,9 @@ int main(int argc, char *argv[])
 		case opt_noatime:
 			create_atime = 0;
 			break;
+		case opt_regular:
+			regular_file = 1;
+			break;
 
 		case 1:
 			if (devname == NULL) {
@@ -356,7 +374,7 @@ int main(int argc, char *argv[])
 	}
 
 	/* Validate device */
-	dev_fd = open_device(devname, &device_bytes);
+	dev_fd = open_device(devname, &device_bytes, regular_file);
 
 	/* Validate parameters */
 	validate_parameters(&block_bytes, &segment_bytes, &stride_bytes, &width,