From ce53f79c2692147164fe4e6ede856c2f26b3028f Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Sun, 1 Apr 2012 07:09:10 +1000 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 --- doc/tgtimg.8.xml | 22 ++++++++++++++++++++++ usr/tgtimg.c | 37 ++++++++++++++++++++++++++++--------- usr/util.h | 16 ++++++++++++++++ 3 files changed, 66 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 @@ -s --size <size> -t --type <media-type> -f --file <path> + -T --thin-provisioning tgtimg --help @@ -126,6 +127,27 @@ Supported media types for tape devices are : + + + + 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. + + + 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. + + + Thin-provisioning uses FALLOC_FL_PUNCH_HOLE which is only available + on some linux filesystems. Thin-provisioning can only be used for + DISK images. + + + + diff --git a/usr/tgtimg.c b/usr/tgtimg.c index f4388d9..286e333 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@gmail.com * @@ -38,6 +38,7 @@ #include "ssc.h" #include "libssc.h" #include "scsi.h" +#include "util.h" #define NO_LOGGING #include "log.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 .\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 +441,21 @@ 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) { + if (ftruncate(fd, size*1024*1024LL) != 0) { + perror("Failed to set file size"); + exit(6); + } + if (unmap_file_region(fd, 0, size*1024*1024LL) != 0) { + perror("Thin provisioning not available on" + " this file"); + exit(5); + } + } else { + if (posix_fallocate(fd, 0, size*1024*1024LL) == -1) { + perror("posix_fallocate failed."); + exit(3); + } } free(buf); @@ -456,7 +471,7 @@ static int sbc_new(int op, char *path, char *capacity, char *media_type) return 0; } -static int sbc_ops(int op, char *path, char *capacity, char *media_type) +static int sbc_ops(int op, char *path, char *capacity, char *media_type, int thin) { if (op == OP_NEW) { if (!media_type) { @@ -471,7 +486,7 @@ static int sbc_ops(int op, char *path, char *capacity, char *media_type) eprintf("Missing the capacity param\n"); usage(1); } - return sbc_new(op, path, capacity, media_type); + return sbc_new(op, path, capacity, media_type, thin); } else { eprintf("unknown the operation type\n"); usage(1); @@ -489,6 +504,7 @@ int main(int argc, char **argv) int dev_type = TYPE_TAPE; int op = -1; char *path = NULL; + int thin = 0; while ((ch = getopt_long(argc, argv, short_options, long_options, &longindex)) >= 0) { @@ -514,6 +530,9 @@ int main(int argc, char **argv) case 'h': usage(0); break; + case 'T': + thin = 1; + break; default: eprintf("unrecognized option '%s'\n", optarg); usage(1); @@ -543,7 +562,7 @@ int main(int argc, char **argv) mmc_ops(op, path, media_type); break; case TYPE_DISK: - sbc_ops(op, path, media_capacity, media_type); + sbc_ops(op, path, media_capacity, media_type, thin); break; default: eprintf("unsupported the device type operation\n"); diff --git a/usr/util.h b/usr/util.h index e75b23a..4bf157d 100644 --- a/usr/util.h +++ b/usr/util.h @@ -5,6 +5,7 @@ #include #include #include +#include #include #include #include @@ -159,4 +160,19 @@ int concat_buf_finish(struct concat_buf *b); int concat_write(struct concat_buf *b, int fd, int offset); void concat_buf_release(struct concat_buf *b); + +/* If we have recent enough glibc to support PUNCH HOLE we try to unmap + * the region. + */ +static inline int unmap_file_region(int fd, off_t offset, off_t length) +{ +#ifdef FALLOC_FL_PUNCH_HOLE + if (fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + offset, length) == 0) + return 0; +#endif + return -1; +} + + #endif -- 1.7.3.1