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Groups > linux.kernel > #1741863
| From | Linus Torvalds <torvalds@linux-foundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively |
| Date | 2017-09-29 01:40 +0200 |
| Message-ID | <uuQzo-6Ul-15@gated-at.bofh.it> (permalink) |
| References | <uuGql-C7-5@gated-at.bofh.it> <uuGqm-C7-31@gated-at.bofh.it> <uuPah-6b6-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Sep 28, 2017 at 3:02 PM, Dave Chinner <david@fromorbit.com> wrote:
> On Thu, Sep 28, 2017 at 08:39:33AM -0400, Mimi Zohar wrote:
>> Don't attempt to take the i_rwsem, if it has already been taken
>> exclusively.
>>
>> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
>
> That's bloody awful.
>
> The locking in filesystem IO paths is already complex enough without
> adding a new IO path semantic that says "caller has already locked
> the i_rwsem in some order and some dependencies that we have no idea
> about".
I do have to admit that I never got a satisfactory answer on why IMA
doesn't just use its own private per-inode lock for this all.
It isn't using the i_rwsem for file consistency reasons anyway, so it
seems to be purely about serializing the actual signature generation
with the xattr writing, but since IMA does those both, why isn't IMA
just using its own lock (not the filesystem lock) to do that?
Linus
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[RFC PATCH 0/3] define new read_iter file operation rwf flag Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 14:50 +0200
[RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 14:50 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Dave Chinner <david@fromorbit.com> - 2017-09-29 00:10 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-29 01:40 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-29 02:20 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-29 02:40 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-29 04:00 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-29 05:30 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively ebiederm@xmission.com (Eric W. Biederman) - 2017-10-01 03:40 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-01 14:10 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-10-01 20:50 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Dave Chinner <david@fromorbit.com> - 2017-10-02 00:40 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-10-02 01:20 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Dave Chinner <david@fromorbit.com> - 2017-10-02 06:00 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 01:50 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively ebiederm@xmission.com (Eric W. Biederman) - 2017-10-02 05:30 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 14:30 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Dave Chinner <david@fromorbit.com> - 2017-10-02 06:40 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 14:20 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Jeff Layton <jlayton@redhat.com> - 2017-10-02 14:50 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively ebiederm@xmission.com (Eric W. Biederman) - 2017-10-02 00:10 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-10-02 00:30 +0200
Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 02:00 +0200
[RFC PATCH 1/3] fs: define new read_iter rwf flag Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 14:50 +0200
Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Matthew Wilcox <willy@infradead.org> - 2017-09-28 16:00 +0200
Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 16:40 +0200
Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-28 18:00 +0200
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