On Tue, Feb 13, 2018 at 05:50:43PM +0800, Anand Jain wrote:
> As -o subvolid mount option is an u64 manage it as %u for
> token verifications, instead of %s.
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> ---
> fs/btrfs/super.c | 23 ++++++++++-------------
> 1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 8112619cac95..bf629c8a6a47 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -336,7 +336,7 @@ enum {
> static const match_table_t tokens = {
> {Opt_degraded, "degraded"},
> {Opt_subvol, "subvol=%s"},
> - {Opt_subvolid, "subvolid=%s"},
> + {Opt_subvolid, "subvolid=%u"},
This gets implemented as simple_strtoul, deep in the perser it uses an
unsigned long long and then casts to usigned long. Long and long-long
are same only on subset of architectures, so we'd need to either extend
teh parser capabilities to really do u64 or we'd have to use the %s and
match_u64.
Though a subvolid larger than full 32bit number is unlikely, for sake of
correctness I think we should stick to the constraints of the subvolid
that allows u64.
> {Opt_device, "device=%s"},
> {Opt_nodatasum, "nodatasum"},
> {Opt_datasum, "datasum"},
> @@ -964,8 +964,8 @@ static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
> {
> substring_t args[MAX_OPT_ARGS];
> char *opts, *orig, *p;
> - char *num = NULL;
> int error = 0;
> + u64 subvolid;
>
> if (!options)
> return 0;
> @@ -995,18 +995,15 @@ static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
> }
> break;
> case Opt_subvolid:
> - num = match_strdup(&args[0]);
> - if (num) {
> - *subvol_objectid = memparse(num, NULL);
> - kfree(num);
> - /* we want the original fs_tree */
> - if (!*subvol_objectid)
> - *subvol_objectid =
> - BTRFS_FS_TREE_OBJECTID;
> - } else {
> - error = -EINVAL;
> + error = match_u64(&args[0], &subvolid);
So this is the right way (with the %s), as memparse accepts the size
suffixes (K/M/G/...), that we don't want for a subvolume id.
> + if (error)
> goto out;
> - }
> +
> + /* we want the original fs_tree */
> + if (subvolid == 0)
> + subvolid = BTRFS_FS_TREE_OBJECTID;
> +
> + *subvol_objectid = subvolid;
> break;
> case Opt_subvolrootid:
> pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
> --
> 2.7.0
>
> --
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