Call the BLKDISCARD ioctl to mark the whole disk as unused before creating
a new filesystem. This will allow SSDs, Arrays with thin provisioning support
and virtual machines to make smarter allocation decisions.
Add a new -K option to prevent mkfs from discarding blocks to aid
trouble-shooting or specialized requirements.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: xfsprogs-dev/mkfs/xfs_mkfs.c
===================================================================
--- xfsprogs-dev.orig/mkfs/xfs_mkfs.c 2009-10-07 21:47:31.000000000 +0000
+++ xfsprogs-dev/mkfs/xfs_mkfs.c 2009-10-07 22:25:29.000000000 +0000
@@ -605,6 +605,20 @@ done:
free(buf);
}
+static void
+discard_blocks(dev_t dev, __uint64_t nsectors)
+{
+ int fd;
+
+ /*
+ * We intentionally ignore errors from the discard ioctl. It is
+ * not necessary for the mkfs functionality but just an optimization.
+ */
+ fd = libxfs_device_to_fd(dev);
+ if (fd > 0)
+ platform_discard_blocks(fd, 0, nsectors << 9);
+}
+
int
main(
int argc,
@@ -681,6 +695,7 @@ main(
int nvflag;
int nci;
int Nflag;
+ int discard;
char *p;
char *protofile;
char *protostring;
@@ -741,7 +756,7 @@ main(
xi.isdirect = LIBXFS_DIRECT;
xi.isreadonly = LIBXFS_EXCLUSIVELY;
- while ((c = getopt(argc, argv, "b:d:i:l:L:n:Np:qr:s:CfV")) != EOF) {
+ while ((c = getopt(argc, argv, "b:d:i:l:L:n:KNp:qr:s:CfV")) != EOF) {
switch (c) {
case 'C':
case 'f':
@@ -1257,6 +1272,9 @@ main(
case 'N':
Nflag = 1;
break;
+ case 'K':
+ discard = 0;
+ break;
case 'p':
if (protofile)
respec('p', NULL, 0);
@@ -1645,6 +1663,14 @@ main(
}
}
+ if (discard) {
+ discard_blocks(xi.ddev, xi.dsize);
+ if (xi.rtdev)
+ discard_blocks(xi.rtdev, xi.rtsize);
+ if (xi.logdev && xi.logdev != xi.ddev)
+ discard_blocks(xi.logdev, xi.logBBsize);
+ }
+
if (!liflag && !ldflag)
loginternal = xi.logdev == 0;
if (xi.logname)
Index: xfsprogs-dev/include/linux.h
===================================================================
--- xfsprogs-dev.orig/include/linux.h 2009-10-07 21:47:31.000000000 +0000
+++ xfsprogs-dev/include/linux.h 2009-10-07 22:15:32.000000000 +0000
@@ -93,6 +93,20 @@ static __inline__ void platform_uuid_cop
uuid_copy(*dst, *src);
}
+#ifndef BLKDISCARD
+#define BLKDISCARD _IO(0x12,119)
+#endif
+
+static __inline__ int
+platform_discard_blocks(int fd, off64_t start, off64_t end)
+{
+ __uint64_t range[2] = { start, end };
+
+ if (ioctl(fd, BLKDISCARD, &range) < 0)
+ return errno;
+ return 0;
+}
+
#if (__GLIBC__ < 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ <= 1))
# define constpp const char * const *
#else
Index: xfsprogs-dev/include/darwin.h
===================================================================
--- xfsprogs-dev.orig/include/darwin.h 2009-10-07 21:47:31.000000000 +0000
+++ xfsprogs-dev/include/darwin.h 2009-10-07 22:15:32.000000000 +0000
@@ -154,4 +154,10 @@ typedef unsigned char uchar_t;
#define HAVE_FID 1
+static __inline__ int
+platform_discard_blocks(int fd, off64_t start, off64_t end)
+{
+ return 0;
+}
+
#endif /* __XFS_DARWIN_H__ */
Index: xfsprogs-dev/include/freebsd.h
===================================================================
--- xfsprogs-dev.orig/include/freebsd.h 2009-10-07 21:47:31.000000000 +0000
+++ xfsprogs-dev/include/freebsd.h 2009-10-07 22:15:32.000000000 +0000
@@ -139,4 +139,10 @@ static __inline__ void platform_uuid_cop
memcpy(dst, src, sizeof(uuid_t));
}
+static __inline__ int
+platform_discard_blocks(int fd, off64_t start, off64_t end)
+{
+ return 0;
+}
+
#endif /* __XFS_FREEBSD_H__ */
Index: xfsprogs-dev/include/irix.h
===================================================================
--- xfsprogs-dev.orig/include/irix.h 2009-10-07 21:47:31.000000000 +0000
+++ xfsprogs-dev/include/irix.h 2009-10-07 22:15:32.000000000 +0000
@@ -337,6 +337,12 @@ static __inline__ void platform_uuid_cop
memcpy(dst, src, sizeof(uuid_t));
}
+static __inline__ int
+platform_discard_blocks(int fd, off64_t start, off64_t end)
+{
+ return 0;
+}
+
static __inline__ char * strsep(char **s, const char *ct)
{
char *sbegin = *s, *end;
Index: xfsprogs-dev/man/man8/mkfs.xfs.8
===================================================================
--- xfsprogs-dev.orig/man/man8/mkfs.xfs.8 2009-10-07 22:19:23.000000000
+0000
+++ xfsprogs-dev/man/man8/mkfs.xfs.8 2009-10-07 22:22:26.000000000 +0000
@@ -36,6 +36,8 @@ mkfs.xfs \- construct an XFS filesystem
.I label
] [
.B \-N
+] [
+.B \-K
]
.I device
.SH DESCRIPTION
@@ -714,6 +716,9 @@ manual entries for additional informatio
.B \-N
Causes the file system parameters to be printed out without really
creating the file system.
+.TP
+.B \-K
+Do not attempt to discard blocks at mkfs time.
.SH SEE ALSO
.BR xfs (5),
.BR mkfs (8),
|