On 2019/8/14 上午9:04, Jeff Mahoney wrote:
> If a user attempts to resize a file system to a size under 256MiB,
> it will be rejected with EINVAL and get then unhelpful error message
> "ERROR: unable to resize '/path': Invalid argument."
>
> This commit performs that check before issuing the ioctl to report
> a more sensible error message. We also do overflow/underflow
> checking when -/+ size is used and report those errors as well.
>
> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
> ---
> cmds/filesystem.c | 41 +++++++++++++++++++++++++++++++++++++++++
> common/utils.c | 2 +-
> common/utils.h | 2 +-
> 3 files changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/cmds/filesystem.c b/cmds/filesystem.c
> index 4f22089a..e3415126 100644
> --- a/cmds/filesystem.c
> +++ b/cmds/filesystem.c
> @@ -34,10 +34,12 @@
> #include "kerncompat.h"
> #include "ctree.h"
> #include "common/utils.h"
> +#include "common/device-utils.h"
> #include "volumes.h"
> #include "cmds/commands.h"
> #include "cmds/filesystem-usage.h"
> #include "kernel-lib/list_sort.h"
> +#include "kernel-lib/overflow.h"
> #include "disk-io.h"
> #include "common/help.h"
> #include "common/fsfeatures.h"
> @@ -1062,6 +1064,41 @@ next:
> }
> static DEFINE_SIMPLE_COMMAND(filesystem_defrag, "defragment");
>
> +static int check_resize_size(const char *path, const char *amount)
> +{
> + int mod = 0;
> + u64 oldsize = 0, size, newsize;
> +
> + if (*amount == '-')
> + mod = -1;
> + else if (*amount == '+')
> + mod = 1;
> +
> + if (mod) {
> + amount++;
> + oldsize = disk_size(path);
> + if (oldsize == 0)
> + return -1;
> + }
> +
> + size = parse_size(amount);
> +
> + if (mod == -1 && check_sub_overflow(oldsize, size, &newsize)) {
> + error("can't resize to negative size");
> + return -1;
> + } else if (mod == 1 && check_add_overflow(oldsize, size, &newsize)) {
> + error("can't resize to larger than 16EiB");
> + return -1;
> + } else
> + newsize = size;
> +
> + if (newsize < SZ_256M) {
> + error("can't resize to size smaller than 256MiB");
> + return -1;
> + }
> + return 0;
> +}
> +
> static const char * const cmd_filesystem_resize_usage[] = {
> "btrfs filesystem resize [devid:][+/-]<newsize>[kKmMgGtTpPeE]|[devid:]max <path>",
> "Resize a filesystem",
> @@ -1110,6 +1147,10 @@ static int cmd_filesystem_resize(const struct cmd_struct *cmd,
> if (fd < 0)
> return 1;
>
> + res = check_resize_size(path, amount);
> + if (res < 0)
> + return 1;
> +
> printf("Resize '%s' of '%s'\n", path, amount);
> memset(&args, 0, sizeof(args));
> strncpy_null(args.name, amount);
> diff --git a/common/utils.c b/common/utils.c
> index ad938409..f2a10ccc 100644
> --- a/common/utils.c
> +++ b/common/utils.c
> @@ -638,7 +638,7 @@ static int fls64(u64 x)
> return 64 - i;
> }
>
> -u64 parse_size(char *s)
> +u64 parse_size(const char *s)
Although a good change, not sure if David will ask for an explict patch
for that.
Despite that, looks good.
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Thanks,
Qu
> {
> char c;
> char *endptr;
> diff --git a/common/utils.h b/common/utils.h
> index 7867fb0a..0ef1d6e8 100644
> --- a/common/utils.h
> +++ b/common/utils.h
> @@ -65,7 +65,7 @@ int pretty_size_snprintf(u64 size, char *str, size_t str_bytes, unsigned unit_mo
> #define pretty_size(size) pretty_size_mode(size, UNITS_DEFAULT)
> const char *pretty_size_mode(u64 size, unsigned mode);
>
> -u64 parse_size(char *s);
> +u64 parse_size(const char *s);
> u64 parse_qgroupid(const char *p);
> u64 arg_strtou64(const char *str);
> int open_file_or_dir(const char *fname, DIR **dirstream);
>
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