btrfs-progs: add discard support to mkfs

Discard the whole device before starting to create the filesystem structures.
Modelled after similar support in mkfs.xfs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Christoph Hellwig 2011-04-21 16:24:07 -04:00 committed by Chris Mason
parent b4d668ee6b
commit 43a06f07c7
2 changed files with 38 additions and 4 deletions

View File

@ -732,13 +732,26 @@ int do_add_volume(int nargs, char **args)
return 12;
}
for(i=1 ; i < (nargs-1) ; i++ ){
for (i = 1; i < (nargs-1); i++ ){
struct btrfs_ioctl_vol_args ioctl_args;
int devfd, res;
u64 dev_block_count = 0;
struct stat st;
int mixed = 0;
res = check_mounted(args[i]);
if (res < 0) {
fprintf(stderr, "error checking %s mount status\n",
args[i]);
ret++;
continue;
}
if (res == 1) {
fprintf(stderr, "%s is mounted\n", args[i]);
ret++;
continue;
}
devfd = open(args[i], O_RDWR);
if (!devfd) {
fprintf(stderr, "ERROR: Unable to open device '%s'\n", args[i]);
@ -746,8 +759,8 @@ int do_add_volume(int nargs, char **args)
ret++;
continue;
}
ret = fstat(devfd, &st);
if (ret) {
res = fstat(devfd, &st);
if (res) {
fprintf(stderr, "ERROR: Unable to stat '%s'\n", args[i]);
close(devfd);
ret++;
@ -781,7 +794,7 @@ int do_add_volume(int nargs, char **args)
}
close(fdmnt);
if( ret)
if (ret)
return ret+20;
else
return 0;

21
utils.c
View File

@ -50,6 +50,20 @@
static inline int ioctl(int fd, int define, u64 *size) { return 0; }
#endif
#ifndef BLKDISCARD
#define BLKDISCARD _IO(0x12,119)
#endif
static int
discard_blocks(int fd, u64 start, u64 len)
{
u64 range[2] = { start, len };
if (ioctl(fd, BLKDISCARD, &range) < 0)
return errno;
return 0;
}
static u64 reference_root_table[] = {
[1] = BTRFS_ROOT_TREE_OBJECTID,
[2] = BTRFS_EXTENT_TREE_OBJECTID,
@ -537,6 +551,13 @@ int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
printf("SMALL VOLUME: forcing mixed metadata/data groups\n");
*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);
ret = zero_dev_start(fd);
if (ret) {
fprintf(stderr, "failed to zero device start %d\n", ret);