Messages in this thread |  | | Date | Tue, 4 Feb 2020 19:21:10 -0800 | From | Matthew Wilcox <> | Subject | Re: [PATCH v5] Add a "nosymfollow" mount option. |
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On Tue, Feb 04, 2020 at 04:49:48PM -0700, Ross Zwisler wrote: > On Tue, Feb 4, 2020 at 3:11 PM Ross Zwisler <zwisler@chromium.org> wrote: > > On Tue, Feb 4, 2020 at 2:53 PM Raul Rangel <rrangel@google.com> wrote: > > > > --- a/include/uapi/linux/mount.h > > > > +++ b/include/uapi/linux/mount.h > > > > @@ -34,6 +34,7 @@ > > > > #define MS_I_VERSION (1<<23) /* Update inode I_version field */ > > > > #define MS_STRICTATIME (1<<24) /* Always perform atime updates */ > > > > #define MS_LAZYTIME (1<<25) /* Update the on-disk [acm]times lazily */ > > > > +#define MS_NOSYMFOLLOW (1<<26) /* Do not follow symlinks */ > > > Doesn't this conflict with MS_SUBMOUNT below? > > > > > > > > /* These sb flags are internal to the kernel */ > > > > #define MS_SUBMOUNT (1<<26) > > > > Yep. Thanks for the catch, v6 on it's way. > > It actually looks like most of the flags which are internal to the > kernel are actually unused (MS_SUBMOUNT, MS_NOREMOTELOCK, MS_NOSEC, > MS_BORN and MS_ACTIVE). Several are unused completely, and the rest > are just part of the AA_MS_IGNORE_MASK which masks them off in the > apparmor LSM, but I'm pretty sure they couldn't have been set anyway. > > I'll just take over (1<<26) for MS_NOSYMFOLLOW, and remove the rest in > a second patch. > > If someone thinks these flags are actually used by something and I'm > just missing it, please let me know.
Afraid you did miss it ...
/* * sb->s_flags. Note that these mirror the equivalent MS_* flags where * represented in both. */ ... #define SB_SUBMOUNT (1<<26)
It's not entirely clear to me why they need to be the same, but I haven't been paying close attention to the separation of superblock and mount flags, so someone else can probably explain the why of it.
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