On Sat, 31 Mar 2012 14:24:22 +1100
ronnie sahlberg <ronniesahlberg@xxxxxxxxx> wrote:
> From fc6859e6ab9dea7bbf71a8f411519dbf5f02f0ef Mon Sep 17 00:00:00 2001
> From: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> Date: Fri, 30 Mar 2012 16:46:38 +1100
> Subject: [PATCH 1/2] TGTIMG: Add support for thin-provisioning
>
> A new flag --ting-provisioning is added to the tgtimg command.
> When used this flag will create a sparse file without any
> allocation guarantee.
> It will also verify that FALLOC_FL_PUNCH_HOLE works.
>
> If such files are created, a future patch to tgtd will add
> support for the UNMAP command that is used by initiators to
> release blocks that are no longer in use.
>
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> ---
> doc/tgtimg.8.xml | 22 ++++++++++++++++++++++
> usr/tgtimg.c | 45 ++++++++++++++++++++++++++++++++++++---------
> 2 files changed, 58 insertions(+), 9 deletions(-)
>
> diff --git a/doc/tgtimg.8.xml b/doc/tgtimg.8.xml
> index 5a787af..e067db0 100644
> --- a/doc/tgtimg.8.xml
> +++ b/doc/tgtimg.8.xml
> @@ -21,6 +21,7 @@
> <arg choice="opt">-s --size <size></arg>
> <arg choice="opt">-t --type <media-type></arg>
> <arg choice="opt">-f --file <path></arg>
> + <arg choice="opt">-T --thin-provisioning</arg>
> </cmdsynopsis>
> <cmdsynopsis>
> <command>tgtimg --help</command>
> @@ -126,6 +127,27 @@ Supported media types for tape devices are :
> </listitem>
> </varlistentry>
>
> + <varlistentry><term><option>-T, --thin-provisioning</option></term>
> + <listitem>
> + <para>
> + This argument makes the allocation of the image format use
> + thin-provisioning. This means that the file created will be a
> + sparse file that will allocate blocks from the filesystem on demand.
> + </para>
> + <para>
> + Be careful when using thin-provisioning. If the filesystem
> + fills up a iSCSI write to a thin-provisioned LUN
> + can fail. Initiators generally do not handle "out of space" errors
> + gracefully.
> + </para>
> + <para>
> + Thin-provisioning uses FALLOC_FL_PUNCH_HOLE which is only available
> + on some linux filesystems. Thin-provisioning can only be used for
> + DISK images.
> + </para>
> + </listitem>
> + </varlistentry>
> +
> </variablelist>
> </refsect1>
>
> diff --git a/usr/tgtimg.c b/usr/tgtimg.c
> index f4388d9..bb417fe 100644
> --- a/usr/tgtimg.c
> +++ b/usr/tgtimg.c
> @@ -1,5 +1,5 @@
> /*
> - * Create blank media files for bs_tape backing store
> + * Create media files for TGTD devices
> *
> * Copyright (C) 2008 Mark Harvey markh794@xxxxxxxxx
> *
> @@ -22,6 +22,7 @@
> #define _XOPEN_SOURCE 600
> #include <errno.h>
> #include <fcntl.h>
> +#include <linux/falloc.h>
> #include <getopt.h>
> #include <inttypes.h>
> #include <stdio.h>
> @@ -59,6 +60,7 @@ struct option const long_options[] = {
> {"size", required_argument, NULL, 's'},
> {"type", required_argument, NULL, 't'},
> {"file", required_argument, NULL, 'f'},
> + {"thin-provisioning", no_argument, NULL, 'T'},
> {NULL, 0, NULL, 0},
> };
>
> @@ -71,7 +73,7 @@ static void usage(int status)
> printf("\
> Linux SCSI Target Framework Image File Utility, version %s\n\
> \n\
> - --op new --device-type tape --barcode=[code] --size=[size] --type=[type] --file=[path]\n\
> + --op new --device-type tape --barcode=[code] --size=[size] --type=[type] --file=[path] [--thin-provisioning]\n\
> create a new tape image file.\n\
> [code] is a string of chars.\n\
> [size] is media size(in megabytes).\n\
> @@ -83,6 +85,7 @@ Linux SCSI Target Framework Image File Utility, version %s\n\
> --op show --device-type tape --file=[path]\n\
> dump the tape image file contents.\n\
> [path] is the tape image file\n\
> + --thin-provisioning create a sparse file for the media\n\
> --help display this help and exit\n\
> \n\
> Report bugs to <stgt@xxxxxxxxxxxxxxx>.\n", TGT_VERSION);
> @@ -414,7 +417,7 @@ static int mmc_ops(int op, char *path, char *media_type)
> return 0;
> }
>
> -static int sbc_new(int op, char *path, char *capacity, char *media_type)
> +static int sbc_new(int op, char *path, char *capacity, char *media_type, int thin)
> {
> int fd;
>
> @@ -438,9 +441,29 @@ static int sbc_new(int op, char *path, char *capacity, char *media_type)
> perror("Failed creating file");
> exit(2);
> }
> - if (posix_fallocate(fd, 0, size*1024*1024LL) == -1) {
> - perror("posix_fallocate failed.");
> - exit(3);
> + if (thin) {
> +#ifdef FALLOC_FL_PUNCH_HOLE
> + if (ftruncate(fd, size*1024*1024LL) != 0) {
> + perror("Failed to set file size");
> + exit(6);
> + }
> + if (fallocate(fd,
> + FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
> + 0, size*1024*1024LL) != 0) {
> + perror("Thin provisioning not available on"
> + " this file");
> + exit(5);
> + }
> +#else
> + perror("This version of tgtimg is not compiled "
> + "with thin-provisioning support.");
> + exit(6);
> +#endif
Great, I tried to find the time to implement this feature.
We avoid using ifdef in *.c. Can you create a helper function for
discard stuff in util.h? I guess the function can be used in both
patches.
--
To unsubscribe from this list: send the line "unsubscribe stgt" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
