btrfs-progs: mkfs: add option to skip trim

Signed-off-by: Chris Mason <chris.mason@fusionio.com>

man/mkfs.btrfs.8.in

@@ -63,6 +63,9 @@ Specify the sectorsize, the minimum block allocation.
 \fB\-r\fR, \fB\-\-rootdir \fIrootdir\fR
 Specify a directory to copy into the newly created fs.
 .TP
+\fB\-T\fR, \fB\-\-nodiscard \fR
+Do not perform whole device TRIM operation by default.
+.TP
 \fB\-V\fR, \fB\-\-version\fR
 Print the \fBmkfs.btrfs\fP version and exit.
 .SH AVAILABILITY

mkfs.c

@@ -348,6 +348,7 @@ static void print_usage(void)
 	fprintf(stderr, "\t -n --nodesize size of btree nodes\n");
 	fprintf(stderr, "\t -s --sectorsize min block allocation\n");
 	fprintf(stderr, "\t -r --rootdir the source directory\n");
+	fprintf(stderr, "\t -T --nodiscard do not perform whole device TRIM\n");
 	fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
 	exit(1);
 }
@@ -409,6 +410,7 @@ static struct option long_options[] = {
 	{ "data", 1, NULL, 'd' },
 	{ "version", 0, NULL, 'V' },
 	{ "rootdir", 1, NULL, 'r' },
+	{ "nodiscard", 0, NULL, 'T' },
 	{ 0, 0, 0, 0}
 };
 
@@ -1224,6 +1226,7 @@ int main(int ac, char **av)
 	int mixed = 0;
 	int data_profile_opt = 0;
 	int metadata_profile_opt = 0;
+	int nodiscard = 0;
 
 	char *source_dir = NULL;
 	int source_dir_set = 0;
@@ -1234,7 +1237,7 @@ int main(int ac, char **av)
 
 	while(1) {
 		int c;
-		c = getopt_long(ac, av, "A:b:l:n:s:m:d:L:r:VM", long_options,
+		c = getopt_long(ac, av, "A:b:l:n:s:m:d:L:r:VMT", long_options,
 				&option_index);
 		if (c < 0)
 			break;
@@ -1280,6 +1283,9 @@ int main(int ac, char **av)
 				source_dir = optarg;
 				source_dir_set = 1;
 				break;
+			case 'T':
+				nodiscard=1;
+				break;
 			default:
 				print_usage();
 		}
@@ -1318,7 +1324,8 @@ int main(int ac, char **av)
 			exit(1);
 		}
 		first_file = file;
-		ret = btrfs_prepare_device(fd, file, zero_end, &dev_block_count, &mixed);
+		ret = __btrfs_prepare_device(fd, file, zero_end,
+				&dev_block_count, &mixed, nodiscard);
 		if (block_count == 0)
 			block_count = dev_block_count;
 		else if (block_count > dev_block_count) {
@@ -1416,8 +1423,8 @@ int main(int ac, char **av)
 			continue;
 		}
 		dev_block_count = block_count;
-		ret = btrfs_prepare_device(fd, file, zero_end,
-					   &dev_block_count, &mixed);
+		ret = __btrfs_prepare_device(fd, file, zero_end,
+					   &dev_block_count, &mixed, nodiscard);
 		mixed = old_mixed;
 		BUG_ON(ret);
 

utils.c

@@ -538,6 +538,12 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 
 int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
 			 int *mixed)
+{
+	/* discard by default when called from 'device add' */
+	return __btrfs_prepare_device(fd, file, zero_end, block_count_ret, mixed, 0);
+}
+int __btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
+			 int *mixed, int nodiscard)
 {
 	u64 block_count;
 	u64 bytenr;
@@ -564,11 +570,13 @@ int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
 		*mixed = 1;
 	}
 
-	/*
-	 * We intentionally ignore errors from the discard ioctl.  It is
-	 * not necessary for the mkfs functionality but just an optimization.
-	 */
-	discard_blocks(fd, 0, block_count);
+	if (!nodiscard) {
+		/*
+		 * We intentionally ignore errors from the discard ioctl.  It is
+		 * not necessary for the mkfs functionality but just an optimization.
+		 */
+		discard_blocks(fd, 0, block_count);
+	}
 
 	ret = zero_dev_start(fd);
 	if (ret) {

utils.h

@@ -28,6 +28,8 @@ int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, u64 objectid);
 int btrfs_prepare_device(int fd, char *file, int zero_end,
 			 u64 *block_count_ret, int *mixed);
+int __btrfs_prepare_device(int fd, char *file, int zero_end,
+			 u64 *block_count_ret, int *mixed, int nodiscard);
 int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root, int fd, char *path,
 		      u64 block_count, u32 io_width, u32 io_align,