Messages in this thread | | | Subject | Re: [patch 00/13] vfs: add helpers to check r/o bind mounts | From | Dave Hansen <> | Date | Thu, 24 Apr 2008 10:55:17 -0700 |
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On Thu, 2008-04-24 at 17:37 +0200, Miklos Szeredi wrote: > Why are those so important? Yes, if we have multiple vfs_() calls, > surround them with an extra want/drop pair. We do already do multiple > overlapping want/drop pairs with O_TRUNC and O_CREAT (AFAIR).
The one that I remember is the pair that we take for O_CREAT and the nameidata_to_filp() in do_filp_open() that we do on it after the creation and hold while the file is open.
The only reason for this one is that we want to shut down a potential race that would allow the file to be created, then still return a -EROFS because someone did a r/w->r/o transition between the create an the nameidata_to_filp().
We could pass some information into nameidata_to_filp()->__dentry_open() telling it that we already have a write and it doesn't need to take one, but I think having the two nested writes is cleaner.
Is that the case you're thinking of?
-- Dave
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