On Sat, Jan 23, 2021 at 03:37:20PM +0000, Sidong Yang wrote:
> This patch make output of filesystem-resize command more readable and
> give detail information for users. This patch provides more information
> about filesystem like below.
>
> Before:
> Resize '/mnt' of '1:-1G'
>
> After:
> Resize device id 1 (/dev/vdb) from 4.00GiB to 3.00GiB
>
> Signed-off-by: Sidong Yang <[email protected]>
> ---
> v2:
> - print more detailed error
> - covers all the possibilities format provides
> ---
> cmds/filesystem.c | 112 +++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 111 insertions(+), 1 deletion(-)
>
> diff --git a/cmds/filesystem.c b/cmds/filesystem.c
> index ba2e5928..cec3f380 100644
> --- a/cmds/filesystem.c
> +++ b/cmds/filesystem.c
> @@ -28,6 +28,7 @@
> #include <linux/limits.h>
> #include <linux/version.h>
> #include <getopt.h>
> +#include <limits.h>
>
> #include <btrfsutil.h>
>
> @@ -1074,6 +1075,109 @@ static const char * const
> cmd_filesystem_resize_usage[] = {
> NULL
> };
>
> +static int check_resize_args(const char *amount, const char *path) {
> + struct btrfs_ioctl_fs_info_args fi_args;
> + struct btrfs_ioctl_dev_info_args *di_args = NULL;
> + int ret, i, devid = 0, dev_idx = -1;
devid should be u64
> + const char *res_str = NULL;
> + char *devstr = NULL, *sizestr = NULL;
> + u64 new_size = 0, old_size = 0;
> + int mod = 0;
> + char amount_dup[BTRFS_VOL_NAME_MAX];
Bffer of a fixed size ...
> +
> + ret = get_fs_info(path, &fi_args, &di_args);
> +
> + if (ret) {
> + error("unable to retrieve fs info");
> + return 1;
> + }
> +
> + if (!fi_args.num_devices) {
> + error("no devices found");
> + free(di_args);
> + return 1;
> + }
> +
> + strcpy(amount_dup, amount);
... and strcpy from a user specified buffer, this is from chapter 1 of
how buffer overflows in C work. Please use safe string copy.
> + devstr = strchr(amount_dup, ':');
> + if (devstr) {
> + sizestr = devstr + 1;
> + *devstr = '\0';
> + devstr = amount_dup;
> +
> + errno = 0;
> + devid = strtoull(devstr, NULL, 10);
> +
> + if (errno) {
> + error("failed to parse devid %s", devstr);
> + free(di_args);
> + return 1;
> + }
> + }
> +
> + dev_idx = -1;
> + for(i = 0; i < fi_args.num_devices; i++) {
> + if (di_args[i].devid == devid) {
> + dev_idx = i;
> + break;
> + }
> + }
> +
> + if (dev_idx < 0) {
> + error("cannot find devid : %d", devid);
> + free(di_args);
> + return 1;
> + }
> +
> + if (!strcmp(sizestr, "max")) {
> + res_str = "max";
> + }
> + else {
> + if (sizestr[0] == '-') {
> + mod = -1;
> + sizestr++;
> + } else if (sizestr[0] == '+') {
> + mod = 1;
> + sizestr++;
> + }
> + new_size = parse_size(sizestr);
> + if (!new_size) {
> + error("failed to parse size %s", sizestr);
> + free(di_args);
> + return 1;
> + }
> + old_size = di_args[dev_idx].total_bytes;
> +
> + if (mod < 0) {
> + if (new_size > old_size) {
> + error("current size is %s which is smaller than
> %s",
> + pretty_size_mode(old_size, UNITS_DEFAULT),
> + pretty_size_mode(new_size,
> UNITS_DEFAULT));
> + free(di_args);
> + return 1;
> + }
> + new_size = old_size - new_size;
> + } else if (mod > 0) {
> + if (new_size > ULLONG_MAX - old_size) {
> + error("increasing %s is out of range",
> + pretty_size_mode(new_size,
> UNITS_DEFAULT));
> + free(di_args);
> + return 1;
> + }
> + new_size = old_size + new_size;
This all got me confused, old_size and new_size sound like absolute
numbers for the size but new_size is in fact used as the delta, or the
relative change.
Otherwise looks good.
> + }
> + new_size = round_down(new_size, fi_args.sectorsize);
> + res_str = pretty_size_mode(new_size, UNITS_DEFAULT);
> + }
> +
> + printf("Resize device id %d (%s) from %s to %s\n", devid,
> di_args[dev_idx].path,
> + pretty_size_mode(di_args[dev_idx].total_bytes, UNITS_DEFAULT),
> + res_str);
> +
> + free(di_args);
> + return 0;
> +}
> +
> static int cmd_filesystem_resize(const struct cmd_struct *cmd,
> int argc, char **argv)
> {
> @@ -1139,7 +1243,13 @@ static int cmd_filesystem_resize(const struct
> cmd_struct *cmd,
> return 1;
> }
>
> - printf("Resize '%s' of '%s'\n", path, amount);
> + ret = check_resize_args(path, amount);
> + if (ret != 0) {
> + close_file_or_dir(fd, dirstream);
> + return 1;
> + }
> +
> +
> memset(&args, 0, sizeof(args));
> strncpy_null(args.name, amount);
> res = ioctl(fd, BTRFS_IOC_RESIZE, &args);
> --
> 2.25.1
