Messages in this thread | | | Date | Wed, 4 Mar 2020 11:39:22 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH 1/2] kernfs: Add option to enable user xattrs |
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Hello,
On Tue, Mar 03, 2020 at 11:37:28AM -0800, Daniel Xu wrote: > It looks like in fs/xattr.c:setxattr, there is already: > > ... > if (size) { > if (size > XATTR_SIZE_MAX) > return -E2BIG; > ... > > where XATTR_SIZE_MAX is defined as 64k. Do you want it even smaller?
Oh, I missed that. Order 5 allocations can still be on the big side tho. Ideally, something like the following?
* Total number of bytes limit as the primary limit so that we can say that for a given cgroup user xattrs don't consume more than X bytes. We can pick an arbitrary number which is large enough for most use cases but not too big. e.g. 128k or whatever.
* Total number of xattrs limit. Again, some arbitrary not too low, not too high limit.
* Switch to kvmalloc() for attr allocation so that we don't have to worry about high order allocations.
Thanks.
-- tejun
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