1 Upstream-Status: Inappropriate [Backport]
2 From e6bd18d8938986c997c45f0ea95b221d4edec095 Mon Sep 17 00:00:00 2001
3 From: Christoph Hellwig <hch@lst.de>
4 Date: Thu, 21 Apr 2011 16:24:07 -0400
5 Subject: [PATCH 15/15] btrfs-progs: add discard support to mkfs
7 Discard the whole device before starting to create the filesystem structures.
8 Modelled after similar support in mkfs.xfs.
10 Signed-off-by: Christoph Hellwig <hch@lst.de>
11 Signed-off-by: Chris Mason <chris.mason@oracle.com>
13 btrfs_cmds.c | 21 +++++++++++++++++----
14 utils.c | 21 +++++++++++++++++++++
15 2 files changed, 38 insertions(+), 4 deletions(-)
17 diff --git a/btrfs_cmds.c b/btrfs_cmds.c
18 index 6de73f4..32f6b25 100644
21 @@ -732,13 +732,26 @@ int do_add_volume(int nargs, char **args)
25 - for(i=1 ; i < (nargs-1) ; i++ ){
26 + for (i = 1; i < (nargs-1); i++ ){
27 struct btrfs_ioctl_vol_args ioctl_args;
29 u64 dev_block_count = 0;
33 + res = check_mounted(args[i]);
35 + fprintf(stderr, "error checking %s mount status\n",
41 + fprintf(stderr, "%s is mounted\n", args[i]);
46 devfd = open(args[i], O_RDWR);
48 fprintf(stderr, "ERROR: Unable to open device '%s'\n", args[i]);
49 @@ -746,8 +759,8 @@ int do_add_volume(int nargs, char **args)
53 - ret = fstat(devfd, &st);
55 + res = fstat(devfd, &st);
57 fprintf(stderr, "ERROR: Unable to stat '%s'\n", args[i]);
60 @@ -781,7 +794,7 @@ int do_add_volume(int nargs, char **args)
69 diff --git a/utils.c b/utils.c
70 index 13373c9..17e5afe 100644
74 static inline int ioctl(int fd, int define, u64 *size) { return 0; }
78 +#define BLKDISCARD _IO(0x12,119)
82 +discard_blocks(int fd, u64 start, u64 len)
84 + u64 range[2] = { start, len };
86 + if (ioctl(fd, BLKDISCARD, &range) < 0)
91 static u64 reference_root_table[] = {
92 [1] = BTRFS_ROOT_TREE_OBJECTID,
93 [2] = BTRFS_EXTENT_TREE_OBJECTID,
94 @@ -537,6 +551,13 @@ int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
95 printf("SMALL VOLUME: forcing mixed metadata/data groups\n");
100 + * We intentionally ignore errors from the discard ioctl. It is
101 + * not necessary for the mkfs functionality but just an optimization.
103 + discard_blocks(fd, 0, block_count);
105 ret = zero_dev_start(fd);
107 fprintf(stderr, "failed to zero device start %d\n", ret);