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| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-01-11 01:17:19 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-01-15 09:36:06 +0300 |
| commit | c64cd6e34ea340adbb2a0a2f99cc884b96dcdca5 (patch) | |
| tree | 87786ffcaf8408cacc0784ea2bd280f93b26c7e2 /include | |
| parent | 1edc8eb2e93130e36ac74ac9c80913815a57d413 (diff) | |
| download | linux-c64cd6e34ea340adbb2a0a2f99cc884b96dcdca5.tar.xz | |
reimplement path_mountpoint() with less magic
... and get rid of a bunch of bugs in it. Background:
the reason for path_mountpoint() is that umount() really doesn't
want attempts to revalidate the root of what it's trying to umount.
The thing we want to avoid actually happen from complete_walk();
solution was to do something parallel to normal path_lookupat()
and it both went overboard and got the boilerplate subtly
(and not so subtly) wrong.
A better solution is to do pretty much what the normal path_lookupat()
does, but instead of complete_walk() do unlazy_walk(). All it takes
to avoid that ->d_weak_revalidate() call... mountpoint_last() goes
away, along with everything it got wrong, and so does the magic around
LOOKUP_NO_REVAL.
Another source of bugs is that when we traverse mounts at the final
location (and we need to do that - umount . expects to get whatever's
overmounting ., if any, out of the lookup) we really ought to take
care of ->d_manage() - as it is, manual umount of autofs automount
in progress can lead to unpleasant surprises for the daemon. Easily
solved by using handle_lookup_down() instead of follow_mount().
Tested-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/namei.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/include/linux/namei.h b/include/linux/namei.h index 7fe7b87a3ded..07bfb0874033 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -34,7 +34,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; /* internal use only */ #define LOOKUP_PARENT 0x0010 -#define LOOKUP_NO_REVAL 0x0080 #define LOOKUP_JUMPED 0x1000 #define LOOKUP_ROOT 0x2000 #define LOOKUP_ROOT_GRABBED 0x0008 |